Storage and Retrieval System

Abstract

A storage and retrieval system comprising: A) a grid framework structure comprising: i) a plurality of storage columns for one or more storage bins to be stored in a vertical stack; ii) a track system (514) disposed on the plurality of storage columns, the track system comprising a plurality of tracks arranged in a grid pattern extending substantially in a horizontal plane, the track system comprising a plurality of grid cells or grid spaces in which the storage bins in the stack can be transported between the plurality of storage columns and a top level of the track system; and B) an inventory handling station assembly (514) comprising a first access station on a first floor and a second access station on a second floor. 04), the first floor being vertically spaced from the second floor for gaining access to the contents of the storage receptacles at first and second access stations on the first and second floors, respectively; C) upper floor port columns (506a, c) extending from the track system to a first access station on the first floor for transferring storage receptacles between the track system and the inventory handling station assembly; and D) lower floor port columns (506b, d) extending from the track system to a second access station on the second floor for transferring storage receptacles between the track system and the inventory handling station assembly.

Description

[Technical Field]

[0001] The present invention relates to the field of remotely operated load handling devices on trucks positioned on grid framework structures for handling containers or boxes stacked in the grid framework structures, and more particularly to grid framework structures for supporting remotely operated load handling devices. [Background technology]

[0002] Storage systems comprising a three-dimensional storage grid structure in which storage bins / boxes are stacked on top of each other are well known. PCT Publication No. WO2015 / 185628A (Ocado) describes a known storage and fulfillment system in which stacks of boxes or containers are arranged within a grid framework structure. The boxes or containers are accessed by remotely operable load handling equipment on a truck located on top of the grid framework structure. A system of this type is illustrated diagrammatically in Figures 1 to 3 of the accompanying drawings.

[0003] As shown in FIGS. 1 and 2 , stackable containers known as boxes or bins 10 are stacked on top of each other to form stacks 12. The stacks 12 are arranged on a grid framework structure 14 in a warehousing or manufacturing environment. The grid framework is comprised of a plurality of storage columns or grid columns. The grid framework structure 14 includes a plurality of upright members or columns 16 supporting horizontal members 18, 20. A first set of parallel horizontal grid members 18 is disposed perpendicular to a second set of parallel horizontal grid members 20 to form a grid structure comprising a plurality of grid cells extending in a horizontal plane and supported by the upright members 16. The members 16, 18, 20 are typically fabricated from metal and typically welded or bolted together, or a combination of both. The boxes 10 are stacked between the members 16, 18, 20 of the grid framework structure 14; thus, the grid framework structure 14 protects the stack 12 of boxes 10 from horizontal movement and guides the vertical movement of the boxes 10. Each grid cell in the grid framework structure has at least one grid column for housing a stack of containers. Figure 1 is a schematic perspective view of the grid framework structure 14, and Figure 2 is a top-down view showing a stack 12 of boxes 10 arranged within the framework structure 14. Each box 10 typically holds multiple product items (not shown), which may be the same or may be of different product types depending on the application.

[0004] The majority of grid columns are dedicated to storing bins (alternatively, "boxes" or "totes") in stacks and are therefore considered storage columns to distinguish them from port columns. Grid framework structures generally have at least one grid column that is not used for storing bins in stacks, but is a location where a robotic load handling device can drop off and / or pick up bins so they can be moved to an access station where the contents of the bin can be accessed from outside the grid framework structure. The grid cell locations where a robotic load handling device can drop off / pick up a bin are called "ports," and the grid columns in which the ports are located are called "port columns."

[0005] The top tier of the grid framework structure 14 includes rails 22 arranged in a grid pattern across the top of the stacks 12. With further reference to FIG. 3 , the rails 22 support a plurality of load handling apparatuses 30. A first set 22a of parallel rails 22 guides movement of the robotic load handling apparatus 30 in a first direction (e.g., the X direction) across the top of the grid framework structure 14, and a second set 22b of parallel rails 22 arranged perpendicular to the first set 22a guides movement of the load handling apparatus 30 in a second direction (e.g., the Y direction) that is perpendicular to the first direction. In this manner, the rails 22 enable movement of the robotic load handling apparatus 30 laterally in two dimensions in the horizontal XY plane, so that the load handling apparatus 30 can be moved to a position above any stack 12.

[0006] A known load handling apparatus 30 shown in FIGS. 4 and 5 comprising a vehicle body 32, where each load handling apparatus 30 covers only one grid space of a grid framework structure 14, is described in PCT Patent Publication No. WO2015 / 019055 (Ocado), incorporated herein by reference. Here, the load handling apparatus 30 comprises a wheel assembly comprising a first set of wheels 34 consisting of a pair of wheels at the front of the vehicle body 32 and a pair of wheels 34 at the rear of the vehicle 32 for engaging a first set of rails or tracks to guide movement of the apparatus in a first direction, and a second set of wheels 36 consisting of a pair of wheels 36 on each side of the vehicle 32 for engaging a second set of rails or tracks to guide movement of the apparatus in a second direction. Each of the sets of wheels is driven to enable movement of the vehicle in the X and Y directions, respectively, along the rails. One or both sets of wheels can be moved vertically to lift each set of wheels off of its respective rail, thereby enabling the vehicle to move in a desired direction.

[0007] The load handling apparatus 30 is equipped with a lifting device or crane mechanism for lifting the storage container from above. The crane mechanism includes a winch tether or cable 38 wound on a spool or reel (not shown) and a grabber device 39. The lifting device includes a set of lifting tethers 38 (one tether near each of the four corners of the grabber device) extending vertically and connected near or at the four corners of a lifting frame 39, otherwise known as grabber devices, for releasable connection to the storage container 10. The grabber devices 39 are configured to releasably grasp the top of the storage container 10 to lift it from a stack of containers in a storage system of the type shown in FIGS. 1 and 2.

[0008] The wheels 34, 36 are positioned around the periphery of a cavity or recess known as a container-receiving recess 40 in the lower portion. The recess is sized to accommodate the container 10 when it is lifted by the crane mechanism, as shown in FIGS. 5(a) and 5(b). When in the recess, the container is lifted off the rail below, allowing the vehicle to move laterally to a different location. Upon reaching a target location, e.g., another stack, an access point in a storage system, or a conveyor belt, the box or container can be lowered from the container-receiving portion and released from the grabber device.

[0009] One significant drawback of prior art systems is that they can only use a bin with one designated footprint. Additionally, the height of the bin is often constrained by the design of the robotic load handler. This generally limits the use of such systems to those items that can fit within the bin. In typical applications, this means that 1-10% of the total volume of items in the storage system require a different handling method, generally manual labor. This means added complexity in the system, lower productivity, and inefficient use of space.

[0010] WO2015 / 197709 (Ocado Innovation Limited) attempts to overcome this problem by providing a grid framework structure having different sized grid cells configured to accommodate different sized bins. Thus, larger items that cannot be stored in a smaller bin can be stored in the larger bin, and smaller items can be stored in the smaller bin. Different sized load handling devices are operable on the grid to move between the different sized bins.

[0011] Restricting a portion of the grid to accommodate larger storage bins reduces the packing density for storing smaller items, which make up the majority of fulfilled orders. Thus, if there is an increased demand for smaller items that can be stored in smaller storage bins, the storage capacity of the grid framework structure may be compromised. Therefore, a need exists for a grid framework structure that has the flexibility to store larger and smaller items, but does not compromise the storage capacity of the grid framework structure.

[0012] The access station may generally be used as a picking station, where one or more items are removed from a storage bin delivered to the picking station, or as a stock "decant" station, where one or more items are placed into a storage bin to replenish the stock. When the contents of a storage bin are required, a robotic load handling device operable on the grid is commanded to move to the grid location where the target storage bin is located and retrieve the target storage bin using the robotic load handling device's lifting device. The target storage bin is transported to a drop-off port in the grid, where it is lowered through a port column to a drop-off area. At the drop-off area, the target storage bin is transported to the access station. At the access station, one or more items are picked up from the storage bin. Once the contents of the storage bin have been removed from the bin at the access station, the storage bin is transported to a pickup station, where the storage bin is then picked up by the robotic load handling device and returned to its original storage location or a new storage location. A conveyor system comprising a conveyor is generally used to transport the storage bin from the drop-off area to the access station as it is unloaded from the port column.

[0013] The rate at which items are picked up from storage bins at an access station depends on the number of storage bins at the access station, which in turn depends on how quickly the storage bins can be transported to and from the access station. In some situations, one or more storage bins are transported to a pickup area and then held in a queue at the access station awaiting pick-up by a robotic load handling device operable on a grid. WO 2018 / 233886 (Autostore Technology AS) attempts to solve this problem by providing a container handling station with a horizontal container carousel comprising a first linear conveyor section and a second linear conveyor section interconnected by two intermediate conveyor sections. Each of the conveyor sections comprises at least one conveyor device for receiving and horizontally moving the containers. The first linear conveyor section (25) is configured directly below the multiple port columns (19, 20), so that any of the container handling vehicles (9) can transport a container (6) between the top of the grid and the first linear conveyor section (25) via any of the multiple port columns (19, 20). The second linear conveyor section (26) is positioned to allow access to the container (6) removed from the grid (4) via the first linear conveyor section (25). The container handling station is too complex and requires multiple moving parts to transport the storage container around the carousel. Furthermore, the speed-limiting step in processing a storage container at the access station depends on how fast the storage container can be transported around the carousel. In most cases, the access station operator is left waiting until the storage container is processed (i.e., the item is picked up) at the access station. Increasing the speed of the carousel moving the storage container through the access station is limited by the speed at which the processed storage container can be picked up from the pickup area. Summary of the Invention

[0014] The present invention alleviates the above problems by providing an inventory handling station assembly with multiple access stations that are vertically spaced at different levels or heights so that more bins can be presented to an operator or robotic picking device at the inventory handling station assembly. The bins are located at different heights so that an operator can easily access and pick items from bins at different levels. Having bins presented to an operator at different heights, compared to presenting bins at the same level, increases the speed at which the operator can access and pick items from bins, since more bins are presented to the operator at any one time. Accordingly, the present invention provides a storage and retrieval system, comprising: A) i) a plurality of storage columns for one or more storage containers to be stored in a vertical stack; ii) a track system disposed above the plurality of storage columns, the track system comprising a plurality of tracks arranged in a grid pattern extending substantially in a horizontal plane, the track system comprising a plurality of grid cells or grid spaces within which storage containers in the stack can be transferred between the plurality of storage columns and an uppermost stage of the track system; a grid framework structure comprising: B) an inventory handling station assembly including a first access station on a first floor and a second access station on a second floor, the first floor being vertically spaced from the second floor for gaining access to the contents of the storage containers at the first and second access stations on the first and second floors, respectively; C) an upper level port column extending from the track system to a first access station on the first level for transferring storage containers between the track system and the inventory handling station assembly; D) a port column on the lower level extending from the track system to a second access station on the second level for transferring containers between the track system and the inventory handling station assembly; A storage and retrieval system is provided.

[0015] The plurality of upright columns may be arranged to form a plurality of storage columns for one or more of the storage containers to be stored vertically in a vertical stack between the plurality of upright columns and guided by them. The upper level port column may be arranged to drop off / pick up storage containers to / from a first access station on the first level, and the lower level port column may be arranged to drop off / pick up storage containers to / from a second access station on the second level, the second level being below the first level. The upper level port column may be a vertical chute having a first opening for receiving storage containers lowered by at least one robotic load handling device operable on a track system through a grid cell and a second opening for allowing the storage container to enter the first access station on the first level. Similarly, the lower level port column, through which storage containers may be transferred between the track system and the inventory handling station assembly, may be a vertical chute for allowing a robotic load handling device operable on a track system to drop off and / or pick up storage containers to / from the second access station on the second level. Alternatively, the upper and / or lower port columns may be equipped with storage container lifting devices that allow storage containers to be automatically transferred between the track system and the first and second access stations, respectively.

[0016] To increase visibility of the contents of vertically spaced storage receptacles at the first and second access stations, optionally, the first access station is laterally offset from the second access station. To limit the footprint of the inventory handling station assembly, optionally, the first access station at least partially covers the second access station. The first and second floors of the inventory handling station assembly are divided or separated, and thus preferably, the first floor of the inventory handling station assembly includes a drop-off area and a pickup area disposed beneath a port column on the upper floor for transferring storage receptacles between the track system and the drop-off and pickup areas on the first floor, and the second floor of the inventory handling station assembly includes a drop-off area and a pickup area disposed beneath a port column on the lower floor for transferring storage receptacles between the track system and the drop-off and pickup areas on the second floor. For definition purposes, the term "drop-off area" may be referred to as a "drop-off station," and the term "pick-up area" may be referred to as a "pick-up station." Thus, the terms "drop-off station" and "drop-off area" may be used interchangeably in patent specifications to refer to the same feature. Similarly, the terms "pickup area" and "pickup station" may be used interchangeably in patent specifications to refer to the same feature. Optionally, the upper and lower port columns comprise drop-off port columns for allowing storage containers to be lowered from the track system to the drop-off area and pickup port columns for allowing storage containers to be picked up from the pickup area toward the track system. The upper and lower port columns are comprised of drop-off port columns where storage containers can be dropped off into the respective drop-off areas on the first and second floors of the inventory handling station assembly. Similarly, the upper and lower port columns are comprised of pickup port columns where storage containers can be picked up from the respective pickup areas on the first and second floors of the inventory handling station assembly.

[0017] Preferably, the drop-off area on the first floor is laterally offset from the drop-off area on the second floor so that the drop-off port columns and pickup port columns of the upper and lower floor port columns can drop off and pick up storage containers between the drop-off and pickup areas on the first and second floors, respectively. Similarly, preferably, the pickup area on the first floor is laterally offset from the pickup area on the second floor. Thus, the drop-off and pickup areas on the first and second floors are located below their respective upper and lower floor port columns. The drop-off and pickup areas on the first floor, which are laterally offset from the drop-off and pickup areas on the second floor, allow the drop-off and pickup port columns of the upper and lower floor port columns to directly drop off and pick up storage containers between their respective drop-off and pickup areas.

[0018] Preferably, the first floor comprises a first conveyor system configured to transport one or more storage containers from the drop-off area to the pickup area via the first access station, and the second floor comprises a second conveyor system configured to transport one or more storage containers from the drop-off area to the pickup area via the second access station, for transporting the storage containers from the drop-off area to the pickup area via the access station at each of the first and second floors of the inventory handling station assembly. More preferably, each of the first conveyor system and the second conveyor system comprises an entrance conveyor unit, an exit conveyor unit and at least one access conveyor unit, wherein the entrance conveyor unit is disposed in the drop-off area and arranged to transport storage containers in a first transport direction from the drop-off area to the first or second access station, the exit conveyor unit is disposed in the pick-up area and arranged to transport storage containers from the at least one access conveyor unit to the pick-up area in a second transport direction, and the at least one access conveyor unit is arranged to transport storage containers from the drop-off area to the pick-up area via the first access station or the second access station, respectively, in a third transport direction.

[0019] At least one access conveyor unit is configured to park the bin at the access station for picking up or transferring items from or to the bin before the bin is transported to the pickup area.

[0020] To conserve space, and therefore footprint, in the inventory handling station assembly, optionally the entrance and exit conveyor units are arranged such that the first conveying direction of the entrance conveyor unit is opposite and parallel to the second conveying direction of the exit conveyor unit, and the third conveying direction of the at least one access conveyor unit is perpendicular to both the first conveying direction of the entrance conveyor unit and the second conveying direction of the exit conveyor unit. In other words, the storage containers move from the drop-off area to the pickup area through the access station in a substantially "U"-shaped direction. Alternatively, the conveyor system may be arranged such that the first conveying direction of the entrance conveyor unit is substantially perpendicular to both the second conveying direction of the exit conveyor unit and the third conveying direction of the at least one access conveyor unit, such that the storage containers move from the drop-off area to the pickup area through the access station in a substantially "L"-shaped direction.

[0021] When one or more items are needed from a target storage container located deep within a stack of storage containers in a storage column, i.e., when multiple storage containers are positioned above the target storage container in a storage column, it may be necessary for a robotic load handling device operable on a track system to temporarily move one or more storage containers above the target storage container to access the target storage container. This process of accessing a target storage container in a stack in a storage column is known in the industry as "mining." The process of digging a target storage container from a stack of storage containers in a storage column may be performed by the same robotic load handling device that is subsequently used to move the target storage container to a drop-off port, or by multiple robotic load handling devices operating in conjunction with one robotic load handling device commanded to remove one or more storage containers from the target storage container and another robotic load handling device that removes the target storage container for delivery to an inventory handling station assembly via a drop-off port. Storage containers removed from the stack may be relocated in their original storage column or, alternatively, to another storage column. The process of "digging" the target container from its stack in the storage column is time consuming and requires at least one additional operation to access the target container.

[0022] The present invention alleviates the mining problem by providing a second track system disposed above the second plurality of storage columns, so that the storage bins can be spread across different areas of the grid framework structure, reducing the need to excavate the storage bins. For example, the storage bins may be distributed across the first plurality of storage columns or the second plurality of storage columns such that more frequently required storage bins are in one area of ​​the grid framework structure, while another area of ​​the grid framework structure is arranged to house less frequently required storage bins. More particularly, the grid framework structure may be i) a second plurality of storage columns for one or more storage containers to be stored in a vertical stack; ii) a second track system disposed above the second plurality of storage columns, the track system comprising a plurality of tracks arranged in a grid pattern extending substantially in a horizontal plane and comprising a plurality of grid cells or grid spaces through which storage containers in the stack may be transferred between the second plurality of storage columns and an uppermost stage of the second track system, wherein the second track system is vertically spaced from the track system such that the track system and the second track system share the same inventory handling station assembly; iii) a second upper level port column extending from the second track system to the first access station on the first level for transferring storage containers between the second track system and the inventory handling station assembly; iv) a second lower level port column extending from the second track system to a second access station on the second level for transferring storage containers between the second track system and the inventory handling station assembly; Further provided are:

[0023] For purposes of this description, the track system will be referred to as the first track system. Another benefit of separating the grid framework structure into a first area with a (first) track system and a second area with a second track system is increased throughput of storage containers to the inventory handling station assembly, since different areas of the grid framework structure with the first and second track systems, respectively, can utilize multiple access stations on different levels of the inventory handling station assembly. As with the first track system, a second upper level port column extends from the second track system to the first access station on the first level for transferring storage containers between the second track system and the inventory handling station assembly, and a second lower level port column extends from the second track system to the second access station on the second level for transferring storage containers between the second track system and the inventory handling station assembly. As explained above, the second upper level port column can be a vertical chute having a first opening for receiving a storage container lowered by at least one load handling device operable on a second track system through a grid cell and a second opening for allowing the storage container to enter the first access station on the first level. Similarly, the second lower level port column, through which storage containers can be transferred between the second track system and the inventory handling station assembly, can be a vertical chute such that a robotic load handling device operable on a track system can drop off and / or pick up the storage container at the second access station on the second level.

[0024] In one example where a track system is vertically disposed above a second track system, at least a portion of the track system (first track system) optionally projects into the second track system to accommodate the upper and lower level port columns of both track systems (first and second track systems). Accordingly, the at least a portion of the track system projecting into the second track system includes an upper level port column for transferring storage containers between the track system and a first access station of the inventory handling station assembly and / or a second lower level port column for transferring storage containers between the track system and a second access station of the inventory handling station assembly. In this manner, a robotic load handling device operable on the track system (first track system) can directly transfer storage containers to the first and / or second access stations of the inventory handling station assembly on different levels via their respective upper and lower level port columns without having to extend through one or more grid cells of the second track system below. Alternatively, upper and / or lower port columns from the track system can extend through one or more grid cells of the second track system to transfer one or more storage containers to the first and second access stations of the inventory handling station assembly via their respective upper and / or lower port columns. A robotic load handling device operable on the second track system can transfer storage containers to the first and second access stations of the inventory handling station assembly via their respective upper and / or lower port columns (second upper port column and second lower port column). In other words, both the track system and the second track system can share the same inventory handling station assembly by having at least a portion of the upper track system protrude into the second track system to enable the robotic load handling device to have access to the inventory handling station assembly below, or can have a common inventory handling station assembly.An additional benefit of first and second track systems on different floors is that they provide a neat and compact way to bring both refrigerated and ambient items to the same inventory handling station assembly. For example, different areas of the grid framework structure comprising the first and second track systems, respectively, may be arranged with separate refrigerated and ambient areas of the grid framework structure. The different areas of the grid framework structure may be augmented to include a third area comprising a freezer section. For purposes of definition, the ambient area covers a temperature range of 21°C to 50°C, the refrigerated temperatures cover a temperature range of 2°C to 8°C, and the freezer temperatures cover a temperature range of -21°C to -16°C. Furthermore, multiple tracks may be provided in the track system and / or the second track system. i) a small cell portion comprising a first set of grid cells; ii) a large cell portion comprising a second set of grid cells; and wherein at least one dimension of each grid cell of the second set of grid cells is a multiple of at least one dimension of each grid cell of the first set of grid cells.

[0025] The small cell portion comprises a first set of parallel tracks extending in a first direction and second and third sets of parallel tracks extending in a second direction, the second direction being substantially perpendicular to the first direction. The first, second, and third sets of parallel tracks are arranged in a grid pattern to define a first set of grid cells, each grid cell of the first set of grid cells having a dimension extending in the first direction and a dimension extending in the second direction to define a first type of grid cell opening. The large cell portion comprises a second set of grid cells, the second set of grid cells being defined by the first and second sets of parallel tracks, each grid cell of the second set of grid cells having a dimension extending in the first direction and a dimension extending in the second direction to define a second type of grid cell opening. In the first direction, the dimensions of the second type grid cell openings are multiples of the dimensions of the first type grid cell openings, and in the second direction, the dimensions of the first type grid cell openings are substantially equal to the dimensions of the second type grid cell openings. The multiple cell sizes of the track system and / or the second track system provide different grid cell openings through which different sized storage bins can exit or be lowered. The different sized storage bins can be used to store different sized items, thereby increasing the flexibility of expanding the storage facilities of the storage and retrieval system of the present invention for miscellaneous items. Multiple parallel sets of tracks can be arranged such that either the first track system or the second track system comprises first and second sets of grid cells, or such that both the first and second track systems comprise first and second sets of grid cells. Alternatively, the track system comprises both the first and second sets of grid cells, and the second track system comprises the first set of grid cells. To enable the robotic load handling device to move on the track system and the second track system, the storage and retrieval system: i) a first type of robotic load handling apparatus comprising a first vehicle wheel assembly comprising a first set of wheels having a first track width and a second set of wheels having a second track width; ii) a second type of robotic load handling device operable on the track system, said second type of robotic load handling device comprising a second vehicle wheel assembly comprising a first set of wheels having a first track width and a second set of wheels having a second track width; Furthermore, wherein the first track width of the first vehicle wheel assembly is substantially equal to the first track width of the second vehicle wheel assembly and the second track width of the second vehicle wheel assembly is a multiple of the second track width of the first vehicle wheel assembly, such that the first type of robotic load handling device is capable of moving in both a first direction and a second direction on the first set of grid cells and the second type of robotic load handling device is capable of moving in both the first direction and the second direction on the second set of grid cells; wherein the first type of robotic load handling device and / or the second type of robotic load handling device are operable on the track system and / or the second track system.

[0026] Further features and aspects of the present invention will become apparent from the following detailed description of illustrative embodiments that proceeds with reference to the drawings. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a schematic diagram of a grid framework structure according to known systems; [Figure 2] 2 is a schematic diagram of a top-down view showing a stack of boxes arranged within the framework structure of FIG. 1. [Figure 3] 1 is a schematic diagram of a known system of load handling equipment operating on a grid framework structure; [Figure 4] 1 is a schematic perspective view of a load handling apparatus showing a lifting device gripping a container from above. [Figure 5](a) A schematic perspective cross-sectional view of the cargo handling device of Figure 4 showing the container receiving space of the cargo handling device, and (b) a schematic perspective cross-sectional view of the cargo handling device of Figure 4 showing a container accommodated in the container receiving space of the cargo handling device. [Figure 6a] 1 is a perspective side view of a known grid framework structure with uniform grid cells; [Figure 6b] Schematic of the top-down view of the grid framework structure shown in Figure 6a. [Figure 6c] Schematic of a top-down view of the configuration of upright columns in a single grid cell. [Figure 7] 1 is a perspective view of a storage space or column within a grid framework structure according to one embodiment of the present invention. [Figure 8] 1 is a schematic diagram of a plan view of a track system according to one embodiment of the present invention; [Figure 8b] 9 is a schematic diagram of an entry point for a first "smaller" type robotic load handling device in the second portion of the track system shown in FIG. 8. [Figure 9] (a) An enlarged view of the track system shown in FIG. 8 showing a first "smaller" type robotic load handling device and a second "larger" type robotic load handling device operable on the track system, and (b) a schematic view of the smaller robotic load handling device positioning itself on a larger grid cell to position its grabber device into engagement with a smaller storage container nested within the larger storage container. [Figure 10] Schematic diagram showing the relationship between (a) a first "smaller" type robotic load handling device with a larger second type grid cell opening and (b) a second "larger" type robotic load handling device with a larger second type grid cell opening. [Figure 11] FIG. 4 is a schematic diagram of a plan view of a track system according to another embodiment of the present invention. [Figure 12] 9 is a schematic diagram of the configuration of the first type storage columns and the second type storage columns under the track system shown in FIG. 8 . [Figure 13]13A-13C are schematic diagrams of storage containers of different sizes suitable for being housed in the first and second types of storage columns in FIG. 12. [Figure 14] FIG. 1 is a cross-sectional view of a "smaller" container of a first type nested within a "larger" container of a second type. [Figure 15] 1 is a schematic diagram of a storage and retrieval system showing first and second types of storage containers being carried to an inventory handling station assembly; [Figure 16] 1 is a schematic diagram of a storage and retrieval system showing first and second types of storage bins being delivered to an inventory handling station with multiple access stations on different floors according to one embodiment of the present invention. [Figure 17] 17 is a schematic diagram of a top view of the storage and retrieval system of FIG. 16 showing the grid framework working structure adjacent to the inventory handling station assembly. [Figure 18] 1 is a schematic diagram of a storage and retrieval system showing different types of robotic load handling devices operable on a track system to transfer storage containers through upper and lower port columns, respectively, to inventory handling station assemblies. [Figure 19] 19 is a front view of the storage and retrieval system of FIG. 18 showing an inventory handling station assembly carrying storage bins from a robotic load handling device operable on a track system. [Figure 20] 20 is a side view of a section of the storage and retrieval system of FIG. 19 showing an upper and lower level port column configuration where storage containers are transferred between first and second portions of the track system to access stations on different levels. DETAILED DESCRIPTION OF THE INVENTION

[0028] FIG. 6a shows a perspective side view of a typical three-dimensional grid framework structure 114 with uniformly sized grid cells. The basic component of the grid framework structure 114 comprises a track system or grid 50 lying on a horizontal surface attached to a supporting framework structure 114b. The supporting framework structure 114b can comprise a plurality of upright columns 116 arranged in a grid pattern, with each upright column located at the intersection of a parallel set of tracks, as shown in FIG. 2 and taught in WO 2015 / 185628 A (Ocado). Alternatively, the supporting framework structure can comprise a plurality of prefabricated modular panels arranged in a grid pattern, the details of which are fully described in PCT application WO 2022034195 A1, in the name of Ocado Innovation Ltd, which is incorporated herein by reference. The structural components of the prefabricated modular panels comprise a plurality of upright columns to support the track system. The feature "upright column" is therefore broadly interpreted to cover upright columns in a three-dimensional grid framework structure as taught in WO2015 / 185628A (Ocado Innovation Ltd) as well as forming part of the prefabricated modular panels taught in WO2022034195A1 in the name of Ocado Innovation Ltd. The terms "upright member" and "upright column" are used interchangeably in the description to mean the same thing.

[0029] As shown in FIG. 6 a, the track system 50 comprises a series of horizontal cross beams or grid members 118, 120 arranged to form a plurality of rectangular frame or grid openings 54; more specifically, a first set of parallel grid members 118 extending in a first direction (X) and a second set of parallel grid members 120 extending in a second direction (Y), the second set of parallel grid members 120 extending transversely relative to the first set of parallel grid members 118 in a substantially horizontal plane. The first and second sets of parallel grid members support first and second sets of parallel tracks 56 a, 56 b, respectively, to define a track system for load handling equipment to move one or more containers over the grid framework structure. Each of the grid members 50 may be comprised of a track support and a separate track or rail attached to the track support. Alternatively, the tracks may be integrally formed with the grid member 50, for example, by extrusion molding.

[0030] Rails or tracks are generally profiled to guide load handling devices on a grid structure, typically providing a single track surface to allow a single load handling device to travel on the track, or a dual track to allow two load handling devices to pass each other on the same track. If the track is profiled to provide a single track, the track has opposing lips along its length (one lip on one side of the track and another lip on the other side of the track) to guide each wheel on the track and constrain each wheel from lateral movement. If the profile is dual track, the track has two pairs of lips along its length to allow wheels of adjacent load handling devices to pass each other in both directions on the same track. To provide two pairs of lips, the track generally has a central ridge or lip and lips on either side of the central ridge.

[0031] The first and second sets of parallel tracks arranged in a grid pattern define a set of grid cells, each with a grid opening or grid spacing through which one or more storage containers can pass. The containers are generally rectangular in shape, with a length greater than its width. Figure 6b shows a plan view of a section of the track system illustrating the arrangement of the first and second sets of parallel tracks in a grid pattern. Each grid cell is rectangular in shape, with a dimension extending in a first direction (X-direction) and a dimension extending in a second direction (Y-direction) to define a grid opening. Generally, each grid cell is rectilinear in shape; therefore, according to Figure 6b, the dimension extending in the first direction is the length of the grid cell, and the dimension extending in the second direction is the width of the grid cell. The length and width of the grid cell are indicated in Figure 6b by the reference characters "L" and "W." For the rectilinear grid cells shown in Figure 6b, the length is greater than the width.

[0032] In a typical grid framework structure, the size of each of the grid openings is uniform throughout the track system to accommodate uniformly sized storage bins. Thus, the footprint of the robotic load handling device is defined by a wheel assembly of the robotic load handling device comprising a first set of wheels and a second set of wheels engageable with a first set of parallel tracks for movement of the robotic load handling device in a first direction and a second set of parallel tracks for movement of the robotic load handling device in a second direction.

[0033] One or more stacks of storage containers are positioned under each grid opening of the track system so that a robotic load handling device operable on the track system can drop and / or pick up storage containers from the stack. The track system is elevated above the first floor by being attached to multiple upright columns 116 at intersections or nodes 58 where grid members 118, 120 intersect to form multiple vertical storage locations 60 for storage containers to be stacked between and guided vertically by the upright columns 116 through multiple substantially rectangular frames 54. For purposes of the present invention, a stack of containers can encompass multiple containers or one or more containers in the stack. The grid framework structure 114 can be considered a linear collection (i.e., a four-walled framework) of upright columns 116 supporting the track system 50 formed from the intersecting horizontal grid members 118, 120. Two or more of the upright columns can be reinforced by at least one diagonal brace member to increase the structural stability of the grid framework structure 114. For purposes of the present invention, the terms "vertical upright column," "upright column," and "upright member" are used interchangeably throughout the description. For purposes of the present description, the intersections 58 constitute nodes of the grid structure.

[0034] FIG. 6c shows a cross-sectional top view of an upright column 116 of the present invention arranged within a grid framework structure to provide storage locations 60 for containers 110 in a stack that are guided through grid cells 54 along the upright column 116. The term "storage location" may sometimes be referred to as "storage column," and such terms may be used interchangeably throughout the description to refer to the same feature. The spacing between the upright columns is sized to accommodate one or more generally rectangular containers or storage bins 110 in the stack. Each of the upright columns is generally tubular. Each of the upright columns 116 includes a hollow central portion 70 with one or more guides 72 attached to or formed on the corners of the upright column 116 that extend along the vertical length of the upright column 116 to guide the movement of the storage containers. The hollow central portions 70 of the upright columns contribute to the low weight of the grid framework structure. Generally, the hollow central portions 70 of the upright columns are box-shaped in cross section. At least one corner of the box section is attached or formed with a guide or corner 72. However, the cross-sectional shape of the hollow center section of the upright column is not limited to a box section, as cross-sections of other shapes such as circular, triangular, etc. are applicable to the present invention.

[0035] The upright columns 116 are spaced apart as shown in FIG. 7 so that guides 72 attached to the corners of different box sections cooperate with one another to provide a single storage location 58 for guiding the movement of containers vertically in a stack along the upright columns. Depending on the position of the upright columns 116 in the grid framework structure, guides 72 are attached to one or all four corners of the box section of the upright columns 116. For example, when forming part of the exterior framework of the grid framework structure, only one or two of the corners of the hollow center section may be provided with guides or corners 72 to cooperate with one or two corners of the containers in the stack. When the upright columns 116 are located inside the grid framework structure, all four corners of the box-shaped center section are provided with guides or corners 72, and each of the upright columns 116 is positioned to cooperate with a corner of four containers 110.

[0036] In a specific embodiment of the present invention, each of the guides 72 is shown as being V-shaped, having a 90-degree cross-sectional profile shaped to abut or accommodate the corner profile of a generally rectangular storage container. As shown in FIG. 6c, the guide comprises two perpendicular plates 72a, 72b (two container guide plates that are perpendicular to each other) extending longitudinally along the upright column 116. The upright column 116 of the present invention may be formed as a single unit, for example, by extrusion. Different materials may be used to fabricate the upright columns, including, but not limited to, metals such as aluminum, steel, or even composite materials that have sufficient structural rigidity to support the grid and load handling equipment moving on the grid structure.

[0037] At least a portion of the plurality of upright columns 116 are held in spatial relationship to one another in a grid framework structure by one or more spacers or struts 74 connected between adjacent upright columns 116 (see FIG. 7 ). The spacers 74 extend transversely (or perpendicularly) to the longitudinal direction of the upright columns 116 and are bolted or riveted to opposing walls of two adjacent upright columns by one or more bolts or rivets. The length of the spacers or struts 74 is sized so that adjacent upright columns 116 are spaced apart sufficiently to accommodate one or more containers in a stack between them. FIG. 7 shows a perspective view of four upright columns 116 held in spaced apart relationship to one another by one or more spacers or struts 74 to form a storage column or storage location 58 sized to accommodate one or more containers in a stack.

[0038] The spacers 74 are sized to fit between the corners of the upright columns 116 that include the guides 72 to allow the upright columns to accommodate stacks of containers between adjacent upright columns 116; i.e., the spacers do not obstruct or cross the area (or vertical storage location) occupied by the guides 72 or guide plates at the corners of the upright columns. One or more spacers / posts 74 are distributed in a spaced-apart relationship along two adjacent upright columns 116 in a grid framework structure (see FIG. 7). The storage location or storage column shown in FIG. 7 includes four adjacent upright columns 116 held in a spaced-apart relationship within the grid framework structure by one or more spacers or posts 74.

[0039] Upon receiving a command, a robotic load handling device operable to move on a track is instructed to pick up a storage container containing an item for fulfilling the command from a stack in the grid framework structure and transport the storage container to an inventory handling station assembly, where the item can then be removed from the storage container and transferred to one or more delivery containers. The term "robotic load handling device" is sometimes referred to as a "bot," and such terms are used interchangeably throughout the description to refer to the same feature. Generally, an inventory handling station assembly includes a container transport assembly for transporting one or more storage containers to an access station where the contents of the containers can be accessed. The container transport assembly is generally a conveyor system including multiple adjacent conveyor units. Further details of the inventory handling station assembly are described below.

[0040] A typical layout of a fulfillment center for the fulfillment of orders comprises two separate grid areas, known as a warm grid area and a refrigerated grid area. Each of the warm grid area and the refrigerated grid area comprises a grid framework structure, i.e., the warm grid area comprises a first grid framework structure and the refrigerated grid area comprises a second grid framework structure. The warm grid area stores food and grocery items at a warm-controlled temperature. The warm-controlled temperature covers a range between substantially 4°C and substantially 21°C, preferably between substantially 4°C and substantially 18°C. Similarly, the refrigerated grid area stores food and grocery items at a refrigerated temperature. The refrigerated temperature covers a range between substantially 0°C and substantially 4°C. The two grid areas, warm and refrigerated, are filled with containers (also known as bins, totes, or boxes) containing various grocery products. Storage bins or bins containing merchandise and groceries are transported by load handling equipment operable on a grid to picking stations or picking areas in the picking aisle, where one or more items are picked from the storage bins or bins at the picking station or picking area and transferred to one or more delivery bins.

[0041] Depending on the type of item, one or more items should each be classified with a specific SKU or stockkeeping unit. As commonly known in the art, SKUs or stockkeeping units are used by retailers to identify and track the retailer's inventory or stock. An SKU is a unique code consisting of letters and numbers that identifies characteristics about each item, such as manufacturer, brand, model, color, and size. This may be recorded with a barcode. The item's characteristics, SKU, and bin identification information are stored in an inventory database accessible by the control system or storage control and communication system. When stocking or replenishing items in a storage system, items delivered from suppliers are transported to a decanting station or supply station. Here, the items are removed from their packaging, registered with a unique stockkeeping unit or SKU depending on the item's type, and placed in a bin at the decanting station. At the decanting station, the bins are transported to a bin lifting device, after which they are lifted to a track system on the grid floor, removed by a load handling device, and transported to a location within the grid framework structure. Generally, a particular SKU is dedicated to a bin, with little or no mixing of SKUs within a single bin. Thus, one or more bins are dedicated to a particular SKU.

[0042] Because the grid framework structure provides the ability to densely pack storage bins, the size of the items stored is largely limited by the size of the storage bin. The size of a storage bin is given by its length x width x depth. A typical standard storage bin is approximately 600 mm x 400 mm x 350 mm in size. While most grocery items can be accommodated within the storage bin, this may not be the case for some non-grocery items, such as electrical appliances or clothing. For fulfillment systems that offer general merchandise, the grid framework structure may need to store items that may not be able to be stored in a standard-sized storage bin. Thus, different sized storage bins would be required to store larger items, which adds a new level of complexity to the grid framework structure and robotic load handling equipment operating on the track system. Even if the grid framework structure taught in WO 2015 / 197709 (Ocado Innovation Limited) provides larger storage bins, there is little or no flexibility to convert the larger storage bins into smaller storage bins if consumer purchasing habits change. Typically, 1-10% of total retail sales of a typical merchandise represent large items, which can vary throughout the year. One or more dedicated robotic load handling devices with a footprint larger than that of robotic load handling devices operating on smaller grid cells can access large bins below the larger grid cells. Dedicating a proportion of the grid framework structure for the storage of large items reduces the effectiveness of the grid framework structure for increasing storage capacity for storing smaller items without intermixing SKUs in a single large bin. Even if multiple different SKU items are stored in a single large bin, a robotic load handling device operating on a larger grid cell would need to pick up the entire bin containing the unwanted SKU items from its storage column and transport it to a picking station.Either way, this represents a less efficient way to store items in the grid framework structure and removes the flexibility of the grid framework structure to vary the ratio of large to small grid cells.

[0043] Furthermore, if most of the items in storage occupy a relatively small portion of the volume of a standard storage bin, the remaining volume of the storage bin will be unused. Given that storage bins are generally standard sizes, and hundreds or even thousands of storage bins are densely packed into a typical storage and retrieval system with a grid framework structure, the accumulation of this empty space from multiple storage bins in storage can represent a relatively large proportion of the storage volume of the grid framework structure.

[0044] The present invention, shown in FIG. 8 , alleviates the above problem by providing a grid framework structure with an integrated or single track system 214 that allows a robotic load handling device having wheel assemblies with different sized footprints to move different sized bins on the track system without being constrained by the specific footprint of the wheel assembly. In contrast to the track configuration shown in FIG. 6 a, the track system 214 according to the present invention, shown in FIG. 8 , includes three sets 218, 220, 222 of parallel tracks arranged in a grid pattern to provide two areas or portions 224, 226 for the movement of different sized bins. As clearly noticeable in FIG. 8 , different sized grid cells 228, 230 are provided by the first portion 224 of the track system and the second portion 226 of the track system 214. The first portion 224 of the track system includes the first set 218 of parallel tracks extending in a first direction (X-direction) and the second and third sets 220, 222 of parallel tracks extending in a second direction (Y-direction). For purposes of consistency and explanation, the first and second directions are represented by orthogonal axes in a two-dimensional horizontal plane, with the first direction along the X-axis and the second direction along the Y-axis. The first, second, and third sets 218, 220, 222 of parallel tracks are arranged in a grid pattern to define a first set 228 of grid cells, whereby each grid cell of the first set of grid cells has a dimension extending in a first direction and a dimension extending in a second direction to define a first-type grid cell opening. The third set 222 of second-direction parallel tracks is parallel to and disposed between the second set 220 of parallel tracks in the first portion 224 of the track system, such that the first-type grid cell opening 54b is smaller and therefore accommodates smaller first-type storage receptacles.

[0045] A second portion 226 of the track system comprises a combination of a first set of grid cells 228 and a second set of grid cells 230. Unlike the first set of grid cells 228, the second set of grid cells 230 is defined only by the first set 218 and second set 220 of parallel tracks, such that each grid cell 230 of the second set of grid cells has a dimension extending in a first direction and a dimension extending in a second direction to define a second-type grid cell opening 54c. A third set of parallel tracks 220 divides the second-type grid cell opening 54c to create the first set of grid cells 228. In the particular embodiment of the invention shown in FIG. 8 , the third set of parallel tracks 220 bisects the second-type grid cell opening 54c to create two first sets 228 of grid cells for each second-type grid cell opening 54c. The absence of the third set of parallel tracks 222 results in the second type grid openings 54c being a multiple of the first type grid openings 54b, and therefore is capable of accommodating larger second type storage containers.

[0046] To allow a robotic load handling device having wheel assemblies with different footprints to move across both the first type 54b and the second type 54c of grid openings, the dimensions of the first and second types of grid openings in one direction are substantially equal. More specifically, in the first direction, the dimensions of the second type grid cell openings 54c are multiples of the dimensions of the first type grid openings 54b, and in the second direction, the dimensions of the first type grid openings are substantially equal to the dimensions of the second type grid openings. The wheel assemblies of the robotic load handling device are adjusted so that the spacing of the sets of wheel pairs can engage with the first, second, and third sets of parallel tracks when moving in the first and second directions. This can be explained with reference to FIGS. 10(a) and 10(b). FIG. 10(a) shows two grid cells 228 of the first type, and FIG. 10(b) shows a single grid cell 230 of the second type. FIG. 10(a) shows a grid cell divided by a track element forming part of the third set of parallel tracks 222. The dimensions of the grid cell 54b are given by its length, indicated by "B," and its width, indicated by "C," in FIG. 10a. FIG. 10b shows a grid cell 54c of a "larger" second set of grid cells formed by the first set 218 and the second set of parallel tracks. The dimensions of the grid cell 54c are given by its length, indicated by "A," and its width, indicated by "B," in FIG. 10b. In the particular embodiment of the invention shown in FIGS. 10(a and b), a third set of parallel tracks is shown bisecting the larger second-type grid cell 54c having a length indicated by "A" to create two smaller first-type grid cells 54b, each having a width, indicated by "C," that is substantially half the length "A." For different robotic load handling devices having different wheel assembly footprints for moving across both the first set 54b and the second set 54c of grid cells, at least one dimension of the grid cell is substantially equal.In Figures 10(a and b), it is clearly evident that the dimensions indicated by the letter "B" extending in the second direction (Y direction) of grid cell types 54b, 54c are substantially equal.

[0047] The wheel assembly of a robotic load handling device can be described in terms of wheel base and track width, as shown in FIGS. 10(a) and 10(b). The wheel base is defined as the distance between the center of the front wheels and the center of the rear wheels of a vehicle. Because the wheel assembly of a robotic load handling device comprises a first set of wheels for engaging with tracks for movement in a first direction and a second set of wheels for engaging with tracks for movement in a second direction, each of the first and second sets of wheels comprises a first wheel base and a second wheel base. The first wheel base represents the distance between the center of the front wheels and the center of the rear wheels of the first set of wheels, and the second wheel base represents the distance between the center of the front wheels and the center of the rear wheels of the second set of wheels.

[0048] When wheel assemblies having different wheel bases move on tracks to straddle the openings of the first type (small) grid 54b and the second type (large) grid 54c, the track width of the wheel assembly is an important aspect of the wheel assembly. Track width refers to the distance between the centerlines of two wheels of a first set or a second set of wheels that share the same axis of rotation, e.g., on the same "imaginary" axis, as shown in FIGS. 10(a) and 10(b). For wheel assemblies comprising first and second sets of wheels, each of the first and second sets of wheels has a first track width and a second track width, respectively. The first track width allows the robotic load handling device to move in a first direction on the track system, and the second track width allows the robotic load handling device to move in a second direction on the track system. 10(a and 10(b)), two types of robotic load handling devices 30b, 30c operable on a track system are shown: a first type "small" robotic load handling device 30b and a second type "large" robotic load handling device 30c. For ease of explanation, the first robotic load handling device 30b may be referred to as the "small" robotic load handling device, and the second type robotic load handling device 30c may be referred to as the "large" robotic load handling device. In order for both the small robotic load handling device 30b and the large robotic load handling device 30c to span across the small first type grid opening 54b and the larger second type grid opening 54c, it is necessary for one of the track widths of the small robotic load handling device 30b and the large robotic load handling device 30c to be substantially equal. Because the dimensions "B" of the first and second type grid openings in the second (Y) direction are substantially equal, the first sets of wheels 134, 234 of both the small robotic load handling device 30b and the large robotic load handling device 30c are arranged to have substantially equal first track widths so that the small robotic load handling device 30b and the large robotic load handling device 30c straddle both the first type grid opening 54b and the second type grid opening 54c.In the schematic diagrams shown in Figures 10(a and b), the first set of wheels 134 of the smaller, first-type robotic load handling apparatus 30b has a track width, indicated by the letter "E" in Figure 10a, that is substantially equal to the track width of the first set of wheels 234 of the larger, second-type robotic load handling apparatus, indicated by the letter "E" in Figure 10b. However, the track width of the second set of wheels 236 of the larger, second-type robotic load handling apparatus, indicated by the letter "F" in Figure 10b, is a multiple of the track width, indicated by the letter "D" of the second set of wheels 136 of the smaller, first-type robotic load handling apparatus in Figure 10a. Thus, the second-type robotic load handling apparatus is capable of accommodating larger storage containers.

[0049] To accommodate larger (second) type storage containers in the track system, the second track width "F" of the second set of wheels 236 of the larger robotic load handling device is a multiple of the second track width "D" of the second set of wheels 136 of the smaller robotic load handling device. The dimensional difference between the first and second track widths of the wheel assemblies of the small and large robotic load handling devices is shown in FIGS. 10(a and b). In the particular embodiment shown in FIG. 10(b), the second track width "F" of the wheel assemblies of the larger second type robotic load handling device is twice as long as the second track width "D" of the wheel assemblies of the smaller first type robotic load handling device. However, the present invention is not limited to the second track width of the wheel assemblies of the larger second type robotic load handling device being twice as long as the second track width of the wheel assemblies of the smaller first type robotic load handling device, but can be any multiple of the second width in a ratio of X:1, where X can be any positive integer, for example, 4. The key to enabling a smaller, first-type robotic load handling device to move across the larger, second set of grid cells in the second portion of the track system is that the first track width "E" of the smaller robotic load handling device is substantially equal to the first track width "E" of the larger robotic load handling device. Thus, the smaller, first set of grid cells 54b in the second portion 226 of the track system 214 can be considered an entry point for the smaller, first-type robotic load handling device 30b to enter the second portion 226 of the track system and access the larger, second-type grid cell openings 54c. Because the first and second track widths of the larger, second-type robotic load handling device are capable of moving along the first and second sets of parallel tracks, the larger, second-type robotic load handling device is capable of moving in both the first and second directions on any portion of the track system.

[0050] During operation, the smaller first-type robotic load handling device 30b can enter the second portion 226 of the track system through the smaller first-type grid cell 228 in one direction (i.e., the second direction) so that its wheel assembly spans across the larger second-type grid opening 54c. In other words, the track width of its wheel assembly spans the width of the larger second-type grid cell 230. In the particular embodiment shown in FIGS. 8 and 10 , the first track width “E” of its wheel assembly spans the second-direction dimension of the larger second-type grid cell 230. The smaller first-type robotic load handling device 30b can then move across the larger second-type grid cell 230 in a direction substantially perpendicular to the direction in which the first-type robotic load handling device entered the second portion 226 of the track system. To allow the smaller, first-type robotic load handling device 30b to enter the second portion 226 of the track system, one or more of the larger, second set 230 of grid cells are adjacent in a first direction by multiple grid cells of the first-type grid cells 228 and adjacent in a second direction by a single grid cell of the first-type grid cells. This is illustrated by the enclosed track system portion 231 in FIG. 8 and the enlarged view of the enclosed portion 231 in FIG. 8b. As clearly shown in FIG. 8b, a grid cell of the “larger” second set 230 of grid cells is partially bounded or adjacent in one direction (the X direction) by two grid cells of the “smaller” first set 228 of grid cells and in the other direction (the Y direction) by one grid cell of the “smaller” first set of grid cells. A boundary 232 between the “larger” second set of grid cells and the “smaller” first set of grid cells is indicated by a dashed line 232 in FIG. 8b. Boundary 232 gives the area of ​​the track system where a "larger" second set of grid cells adjoins a "smaller" first set of grid cells.In Figure 8b, one or more of the "larger" second set of grid cells are adjacent to multiple grid cells of the first set of grid cells in a first direction (the X direction) and to a single grid cell of the first set of grid cells in a second direction (the Y direction). This allows a "smaller" first type robotic load handling device to enter the second portion of the track system in one direction (e.g., the Y direction) indicated by the arrow in Figure 8b and move across the larger grid cells of the second set of grid cells in an orthogonal direction (e.g., the X direction) indicated by the arrow in Figure 8b. One or more of the "larger" grid cells are adjacent to multiple grid cells of the first set of grid cells in the first direction due to a configuration in which a first portion of the track system comprising grid cells of the first set of grid cells is adjacent to a second portion of the track system comprising grid cells of the first and second sets of grid cells.

[0051] Now that the first type robotic load handling device has entered the second portion of the track system in the second direction, it is able to move across the larger second-type grid cell in the first direction. Movement of the first type robotic load handling device across the larger second-type grid cell 230 from the first portion 224 of the track system 214 to the second portion 226 of the track system is shown by the dashed arrows shown in Figure 8 and more clearly in Figure 9a. Distributing the wheel assemblies of the smaller first type robotic load handling device across the width of the larger second-type grid cell 230 enables the smaller first type robotic load handling device to move across the larger second-type grid cell 230.

[0052] While the particular embodiment shown in Figure 8 depicts a track system 214 comprising a first portion 224 comprising a smaller, first set of grid cells 228 and a second portion 226 comprising a mix of the smaller, first set of grid cells 228 and a larger, second set of grid cells 230, a track system 314 according to the present invention is not limited to just two portions and can comprise multiple portions, each of the multiple portions comprising grid cell openings of different sizes. In the particular embodiment shown in Figure 11, the track system 314 comprises an additional, third portion 328 comprising a larger, second set of grid cells 230 adjacent to the second portion 226 of the track system 314, such that the second portion 226 of the track system, comprising a combination of the first and second sets 228 and 230 of grid cells, forms an interface zone between the first and third portions 224 and 328 of the track system 314. The larger, second set of grid cells 230 in the third portion 328 is capable of accommodating a larger, second type of storage container. Also shown in third portion 328 is that one or more of the larger second-type grid cells 230 can accommodate a smaller first-type storage bin, where the smaller first-type storage bin is nested within the larger second-type storage bin. Further details of the nesting of smaller first-type storage bins within larger second-type storage bins are described below.

[0053] One or more stacks of different sized storage bins (e.g., first and second types) are positioned beneath their respective grid cell openings (first and second types) in the first, second, and optionally third portions of the track system so that first and second type robotic load handling devices operable on the track system can drop and / or pick up storage bins from the stacks (see FIG. 12 ). The track system is raised above the first floor by attaching to multiple upright columns 116 at intersections or nodes where grid members intersect to form multiple vertical storage locations for storage bins to be stacked between and guided vertically by the upright columns 116 through the multiple substantially rectangular grid cell openings. The storage bin stacks 112, 115 can contain multiple bins or one or more storage bins. For purposes of defining stacks of different sized storage bins, a stack of smaller first-type storage bins is referred to as a first-type stack of storage bins 112, and a stack of larger second-type storage bins is referred to as a second-type stack of storage bins 115. The first-type stack of storage bins 112 is stored in a first-type vertical storage column 212 located vertically below the first-type grid openings, such that the first-type storage bins can be lifted along the first-type vertical storage locations 212 and through the first-type grid openings. Similarly, the second-type stack of storage bins 115 is stored in a second-type vertical storage column 215 located vertically below the second-type grid openings, such that the first-type storage bins can be lifted along the second-type vertical storage locations and through the second-type grid openings. A plurality of first- and second-type vertical storage locations are located below their respective first-type and second-type grid openings in the first, second, and, optionally, third portions of the track system. This is illustrated in FIG. 12, which shows different types of storage containers 110, 111 stacked in their respective vertical storage columns 212, 215.

[0054] Two or more smaller first-type robotic load handling devices 30b may be nested within a larger second-type storage bin to allow the smaller first-type robotic load handling device 30b to lift items from the larger second-type storage bin when spanning over a second (larger) type grid cell opening 54c (see FIG. 9a). To position itself over the smaller first-type robotic load handling device 30b, one or more position sensors (not shown) may be attached to the body of the smaller first-type robotic load handling device. The position sensors may interact with the track to position the smaller first-type robotic load handling device 30b over the larger grid cell opening 54c so that its grabber device can engage the nested smaller storage bin. The position sensors may be based on optical sensors that interact with markings 113 on the track, as shown in FIG. 9b. Here, at least one track includes equally spaced markings 113 that interact with position sensors mounted on the vehicle body 32 of the smaller, first-type robotic load handling device 30b. The markings 113 enable the smaller, first-type robotic load handling device to accurately position itself over the larger grid cell opening so that its grabber device can engage the correct smaller bin nested within the larger bin. The markings 113 are primarily along the track extending in the second direction of the larger grid cell opening in the second portion of the track system, which comprises a mix of smaller, first set of grid cells 228 and larger, second set of grid cells 230. This allows the smaller first type robotic load handling device to straddle over the larger grid cells 230 in the second portion of the track system and position itself above the smaller storage bins 110a, 110b nested within the larger storage bin 111 to allow its grabber device to engage and lift the smaller storage bins 110a, 110b from the grid cells.

[0055] There are different configurations of smaller first-type storage containers that can be nested within larger second-type storage containers, as shown in Figures 13 and 14. Two or more of the smaller first-type storage containers 110a, 110b can be nested side by side in the larger second-type storage container 111. In the particular embodiment shown in Figure 14, three of the first-type storage containers 110a can be nested side by side in the larger second-type storage container 111. The depth or height of the first-type storage containers 110a, 110b can be reduced so that two or more layers of first-type storage containers 110b can be nested within the larger second-type storage container 111. For example, two layers of three sets of smaller first-type storage containers can be nested within the larger second-type storage container to provide a total of six smaller first-type storage containers nested within the larger second-type storage container. This is shown in the configuration of smaller storage bins 110a, 110b nested within a larger storage bin 111 in Figure 14. Similarly, three layers of sets of three smaller boxes 110a, 110b can be nested within the larger storage bin 111 to give a total of nine smaller storage bins nested within the larger storage bin 111. Each of the smaller storage bins 110a, 110b nested within the larger storage bin 111 can individually store items of different SKUs. For example, multiple SKUs can be stored separately within the larger storage bin by dividing them into separate smaller storage bins 110a, 110b nested within the larger storage bin.

[0056] The cross-sectional areas of the smaller and larger storage containers are sized so that they can be picked up by the first type robotic load handling device 30b and the second type robotic load handling device 30c, respectively. In order for the first type robotic load handling device 30b and the second type robotic load handling device 30c operable on a track system to pick up the smaller storage containers 110a, 110c and the larger storage container 111, the lifting mechanisms of the first type robotic load handling device 30b and the second type robotic load handling device 30c include grabber devices sized to engage the smaller storage containers 110a, 110b and the larger storage container 111, respectively. For example, the frame of the grabber device of the first type robotic load handling device 30b is sized to engage the smaller storage containers 110a, 110b. Similarly, the frame of the grabber device of the second type robotic load handling device 30c is sized to engage the larger storage container 111. In a particular embodiment of the invention shown in Figure 9a, the vehicle bodies of the first type robotic load handling apparatus 30b and the second type robotic load handling apparatus 30c house lifting devices comprising a lifting device assembly and a grabber device such that, in use, the grabber device is configured to removably grasp a smaller storage bin 110a, 110b or a larger storage bin 111, respectively, and lift the storage bin 110a, 110b, 111 from its stack in the grid framework structure into the container-receiving space. The container-receiving space of the first type robotic load handling apparatus 30b and / or the second type robotic load handling apparatus 30c may comprise a cavity or recess located in the vehicle body, for example, as described in WO 2015 / 019055 (Ocado Innovation Limited). Alternatively, the vehicle body of the first type robotic load handling device and / or the second type robotic load handling device may be equipped with a cantilever as taught in WO2019 / 238702 (Autostore Technology AS), in which case the container receiving space is located below the cantilever of the respective first or second type robotic load handling device.In this case, the grabber device is raised by the cantilever so that the grabber device can engage the storage container and lift it from the stack into the container-receiving space below the cantilever.

[0057] The ability to nest smaller storage containers 110a, 110b within larger storage containers 111 increases the flexibility with which the grid framework structure can store items of varying sizes, as the larger storage containers 111 can be used to accommodate the smaller storage containers 110a, 110b. For example, one or more of the larger storage containers 111 in the larger, second-type storage column 215 in the grid framework structure shown in FIG. 12 can be used to accommodate the smaller storage containers 110a, 110b. To gain access to the contents in the smaller storage containers 110a, 110b nested within the larger storage container 111, the larger bot 30c can move the larger storage container 111 on the second portion 226 of the track system 214, 314, which comprises a combination of smaller grid cells 228 and larger grid cells 230. Because the track width of the wheel assembly of the larger bot corresponds to the dimensions of the grid cells extending in the first and second directions, the larger bot can move across both the smaller first-type grid cell openings 54b and the larger second-type grid cell openings 54c in both the first and second directions in the second portion 226 of the track system 214, 314. Thus, the larger bot 30c can deposit the large box 111 with the nested smaller boxes 110a, 110b through the larger second-type grid openings 54c in the second portion 226 of the track system 214, 314. One or more of the large boxes 111 can be stacked in the larger second-type storage column 215 below the larger grid cells 230 in the second portion 226 of the track system 214, 314.Because the second portion 226 of the track system 214, 314 comprises a mixture of smaller grid cells 228 and larger grid cells 230, the smaller grid cells 228 provide entry points for the smaller bot 30b to enter and position itself in the second portion 226 of the track system 214, 314, and thus the track width "E" of its wheel assembly corresponds to one of the dimensions of the larger grid cells per track; i.e., the track width "E" of the wheel assembly of the smaller bot 30b spans one of the dimensions of the larger grid cells 230. For purposes of this definition, the first track width "E" of the smaller bot 30b corresponds to the dimension of the larger grid cell extending in the second direction. This then allows the smaller bot 30b to straddle the smaller grid cell opening 54b and the larger grid cell opening 54c in a direction substantially perpendicular to the entry of the smaller bot 30b. As the small bot 30b straddles the large grid opening 54c in the second portion 226 of the track system 214, 314, the small bot 30b can position itself over the large grid cell opening 54c so that its grabber device can engage and pick up the small storage bins 110a, 110b nested within the larger storage bin 111. Once lifted into the bin-receiving space of the small bot 30b, the small bot 30b can exit the large grid cell and move across the smaller grid cell 228 toward the inventory handling station assembly. The converse is also true, where small bot 30b can deposit smaller storage bins 110a, 110b into larger storage bins 111 held in a stack in larger, second-type storage columns 215 below second portion 226 of track system 214, 314 by lowering smaller storage bins 110a, 110b into larger storage bins 111 through larger grid cell openings 54c in the second portion of the track system. Larger storage bins 111 can remain in a stack in larger, second-type storage columns 215 in the second portion 226 of the track system.

[0058] Optionally, one or more of the larger storage bins 111, including nested smaller storage bins 110a, 110b, can be moved to a storage location by large bot 30c in the second type storage column 215 below the third portion 328 of the track system 314. The third portion 328 of the track system 314, including primarily large grid cells 230, allows the storage and retrieval system of the present invention to provide a separate storage area for the large storage bins 111. The large storage bin 111 below the third portion 328 of the track system 314 can be used to store larger items, or can include smaller storage bins 110a, 110b nested within the larger storage bin 111 for storage of smaller items. This increases the capacity of the storage and retrieval system of the present invention to store smaller items if there is a need to expand the storage capacity of the smaller items beyond the stack of storage bins below the first portion 224 of the track system.

[0059] A typical layout of a storage and retrieval system 401 including a grid framework structure 402 supporting a track system 414 of the present invention is shown in FIG. 15. One or more of the small bots 30b and the large bots 30c are operable on the track system 414. The smaller bot 30b is shown operable on the first section 224 of the track system 414, but can also move in the second section 226 of the track system 414 as described above to pick up the smaller storage bins 110a, 110b. The larger bot 30c is capable of moving on all sections 224, 226, 328 of the track system 414 due to the footprint of its wheel assemblies. Also shown on one side of the grid framework structure 402 is an inventory handling station assembly 404 for receiving and / or returning the small and / or large storage bins 110a, 110b, 111 from storage in the grid framework structure 402.

[0060] Most of the grid columns in the grid framework structure 402 are storage columns, i.e., grid columns, in which bins are stored in stacks. However, the grid typically has at least one grid column that is not used to store bins but that provides a location where a bot can drop off and / or pick up a bin so that the bin can be transported to a location (not shown in the prior art figures) where it can be accessed from outside the grid framework structure or transported into or out of the track system. In the art, such locations are commonly referred to as "ports," and the grid column in which the port is located is sometimes referred to as a "port column" where bins can be transported between the top of the track system and the inventory handling station assembly. The grid framework structure can have a single port column where bins are delivered (dropped off) or removed (picked up) from the inventory handling station assembly, or alternatively, it can have two port columns. The first port column may include, for example, a dedicated drop-off port through which a bot can drop off a storage container to be transported further through the first port column to an access station or transfer station of the inventory handling station assembly, and the second port column may include a dedicated pickup port through which a bot can pick up a storage container transported from the access station or transfer station through the second port column. Storage containers are delivered to the access station and exit the access station through the first and second port columns, respectively. The first and second port columns may be separate port columns for drop-off and pickup of storage containers, or may be a single port column for drop-off and pickup of storage containers. In the specific embodiment of the invention shown in FIG. 15, separate port columns 406, 408, and 410 are used for drop-off and pickup of storage containers.For ease of description of the present invention, first port column 406 will be referred to as the "drop-off" port column and second port column 408 will be referred to as the "pick-up" port column. Track system 414 of the present invention provides separate drop-off / pick-up ports for small first-type storage bins and larger second-type storage bins. The drop-off / pick-up port columns may include chutes extending between each drop-off / pick-up port of the track system to an inventory handling station assembly so that a bot can lower and pick up a storage bin through the drop-off port column or pickup port column, respectively.

[0061] Dedicated drop-off / pickup port columns 406, 408, 410 are provided in the grid framework structure 402 for smaller and larger storage containers. These may be referred to as first-type port columns 406, 408 through which smaller storage containers may be transferred between the drop-off / pickup ports of the track system and the inventory handling station assembly 404, and second-type port columns 410 through which larger storage containers 111 may be transferred between the drop-off / pickup ports of the track system and the inventory handling station assembly 404. Each of the first-type port columns 406, 408 and / or second-type port columns 410 comprises a drop-off port column through which the first-type and / or second-type storage containers are lowered to the inventory handling station assembly and a pickup port column through which the first-type and / or second-type storage containers are picked up toward the track system. These may be separate port columns or a single port column for drop-off and pickup of storage containers. 15, the first type of port column for carrying smaller storage containers comprises separate drop-off port column 406 and pickup column 408. However, the second type of port column 410 is a single port column for drop-off and pickup of larger storage containers 111.

[0062] When the contents of a storage container in the grid framework structure are to be accessed, a smaller or larger bot is commanded to retrieve the target storage container from its location in the grid framework structure, depending on the size of the stored storage container. The operation involves moving the associated bot from its position on the track system to a grid location above the storage column in which the target storage container is located, using the bot's lifting device to pick up the storage container from its storage column, and moving the storage container to a drop-off port. The associated bot depends on whether the target storage container is a smaller storage container from which a smaller bot is commanded to retrieve the target storage container, or a larger storage container from which a larger bot is commanded to retrieve the target storage container. When the storage container is to be stored in the grid framework structure, depending on the size of the storage container, the associated bot is commanded to pick up the storage container from the pickup port and move it to a grid location in the track system above the storage column where it will be lowered to be stored.

[0063] A single inventory handling station assembly 404 or separate inventory handling station assemblies may be provided to handle smaller and larger storage containers transferred from each of the drop-off / pick-up port columns of the first type port columns 406, 408 and the second type port column 410. In general, inventory handling station assemblies 404 known in the art include a port station or drop-off area 416 that cooperates with the drop-off port column 406 to receive the storage container, a pickup area 418 that cooperates with the pickup port column 408 where the storage container can be picked up toward the track system, and an access station 420 where the contents of the storage container can be accessed. As shown in FIG. 15 , the drop-off port column 406 and / or pickup port column 408 may be configured as vertical chutes, where a lifting device of a robotic load handling device operable on the track system can lower or pick up a storage container through the respective drop-off port column and / or pickup port column. Alternatively, the drop-off port column and / or pickup port column may include a box lifting device having one or more movable arms for automatically lowering or lifting the storage containers through the drop-off port column and pickup port column, respectively. For definition purposes, the term "drop-off area" may be referred to as a "drop-off station," and the term "pick-up area" may be referred to as a "pick-up station." Thus, the terms "drop-off station" and "drop-off area" may be used interchangeably in patent specifications to refer to the same feature. Similarly, the terms "pick-up area" and "pick-up station" may be used interchangeably in patent specifications to refer to the same feature.

[0064] The access stations 420 of the inventory handling station assembly 404 of the present invention can serve as a supply station or a decant station, where inventory stored in a grid framework structure is replenished with new stock. A conveyor system 422 is configured to transport storage bins from the drop-off area 416 through the access stations 420 to the pickup area 418. The conveyor system 422 is configured to allow a storage bin to pause at the access station 420 for a predetermined amount of time to allow an operator 424 or a robotic arm to enter the storage bin at the access station 420 and pick up an item therefrom. The conveyor system 422 can include an entrance conveyor unit, an exit conveyor unit, and at least one access conveyor unit, where the entrance conveyor unit is disposed in the drop-off area 416 and is disposed to transport storage bins or containers dropped off from the drop-off port column 406 to the at least one access conveyor unit in a first transport direction. The exit conveyor unit is disposed in the pickup area 418 and is arranged to transport bins or containers from the at least one access conveyor unit to the pickup area in a second transport direction, and the at least one access conveyor unit is arranged to transport containers from the drop-off area to the pickup area in a third transport direction. Each conveyor unit may comprise any suitable configuration of belts, chains, and / or rollers well known in the art of conveyor systems. Typically, at least one access conveyor unit and, optionally, one or more of the rollers of the entrance conveyor unit and / or exit conveyor unit will have an integrated drive motor (not shown), while the remaining rollers may be connected to drive rollers by belts (not shown), or they may be passive.The entrance and exit conveyor units are arranged such that the first conveying direction of the entrance conveyor unit is opposite and parallel to the second conveying direction of the exit conveyor unit, and the third conveying direction of the at least one access conveyor unit is orthogonal to both the first and second conveying directions of both the entrance and exit conveyor units, respectively, i.e., a U-shaped track (see FIG. 15). Alternatively, the conveyor system can be arranged such that the first conveying direction of the entrance conveyor unit is substantially orthogonal to both the second conveying direction of the exit conveyor unit and the third conveying direction of the at least one access conveyor unit. In this aspect of the invention, storage bins travel in an L-shaped direction from the drop-off area, travel horizontally through the access station, and then exit the access station to the pickup area. Three conveyor units provide flexibility in terms of reducing the footprint of the inventory handling station assembly for transporting one or more storage bins or containers from the drop-off area through the access station to the pickup area in multiple conveying directions.

[0065] However, the rate-limiting step in the throughput of storage bins through a storage and retrieval system is the ability to process a storage bin in terms of the number of items that can be picked up or transferred to the storage bin at the access station. Known inventory handling station assemblies in the art suffer from the problem of presenting a limited number of storage bins at the access station. Applicant has realized that an operator can pick up one or more items from a storage bin or transfer items to a storage bin much faster than the number of storage bins presented to the operator at the access station shown in FIG. 15. Thus, the access station becomes a bottleneck as storage bins wait to be processed through the inventory handling station assembly. With the increasing development of automated picking and / or decanting systems, such as robotic arms capable of picking and / or transferring items at rates faster than humans, bottlenecks at the access station have become an increasingly serious problem. Typically, the picking rate at the access station of known inventory handling station assemblies is approximately 400 items per hour, with some automated systems capable of picking in excess of 1,000 items per hour. Attempts have been made to speed up the movement of storage bins through access stations to increase throughput, in some cases using carousels to move storage bins through access stations at faster speeds as taught in technology WO 2018 / 233886 (Autostore Technology AS). Speeding up the movement of storage bins through access stations simply shifts the problem to the exit station, where one or more storage bins are either lifted towards the track system for subsequent retrieval by a robotic load handling device operable on the track system, or accumulated awaiting retrieval by a robotic load handling device operable on the track system.

[0066] The present invention alleviates this problem by providing an inventory handling station assembly 504 in which access stations 520b, 520c are formed on two vertically spaced levels: a first access station 520b on a first level and a second access station 520c on a second level, with the first level being vertically spaced from the second level (see FIGS. 16 and 17). Having multiple access stations 520b, 520c on different levels or elevations allows multiple bins 110a, 110b to be presented to the operator at any one time without having to move the bins through the access stations at a faster rate to achieve a desired picking rate. In a specific embodiment of the present invention, as shown in the plan views of FIGS. 16 and 17, the inventory handling station assembly includes a first access station 520b on a first level and a second access station 520c on a second level, with the first level being at a different elevation than the second level. Having a first access station 520b and a second access station 520c on different levels allows more storage bins to be presented to the operator at any one time, as shown in FIG. 17. For example, as shown in FIG. 19, the first access station 520b can be at chest height of the operator in the inventory handling station assembly, and the second access station 520c can be at waist height, thus allowing the operator 424 to access and pick up one or more items from storage bins on different levels. Having multiple access stations also allows storage bins to be parked at access stations 520b, 520c for longer periods of time without having to rush the storage bins through the access stations, as is the case with prior art solutions, to meet the throughput of storage bins through the inventory handling station assembly. The inventory handling station assembly of the present invention is not limited to two access stations on different levels, but can include any number of access stations on different levels sufficient to allow an operator or robotic device to access and pick up storage bins.

[0067] To allow an operator or robotic device to access storage bins on different levels, the first access station 520b is laterally displaced or offset from the second access station 520c so that the storage bins on different levels are arranged in a tiered manner. The lateral displacement of the storage bins at the first and second access stations improves the presentation of the storage bin's interior space to the operator or robotic device, allowing the operator or robotic device to access storage bins on different levels (see FIG. 17). To save space or limit the footprint of the inventory handling station assembly, the first access station 520b on the first level at least partially covers the second access station 520c on the second level in a tiered manner. The first and / or second access stations may have a slight downward slope, thus increasing the presentation of the storage bins on the first and second levels.

[0068] Also, as shown in Figure 17, on each level, the inventory handling station assembly includes drop-off areas 516a,b that cooperate with drop-off port column 506 for dropping off bins into the inventory handling station assembly, and pickup areas 518a,b that cooperate with pickup port column 508 for picking up bins from the inventory handling station assembly. In the case of an access station with only one level, a single drop-off port column may be positioned to drop off bins at the drop-off area, and a single pickup port column may be positioned to pick up bins from the pickup area. However, when access stations are located on more than one level, as shown in Figures 16 and 17, the grid framework structure includes an upper level port column for transferring bins between the track system and the drop-off / pick-up area on the first level, and a lower level port column for transferring bins between the track system and the drop-off / pick-up area on the second level. The upper and lower level port columns may each be a single column for dropping off and picking up storage containers at different drop-off and pickup areas on the first and second levels, respectively. In other words, a single upper level port column may be provided for dropping off and picking up storage containers at the drop-off and pickup areas on the first level. Similarly, a single lower level port column may be provided for dropping off and picking up storage containers at the drop-off and pickup areas on the second level. In the particular embodiment shown in FIG. 16 , the upper level port column includes separate drop-off and pickup port columns for transferring storage containers to the drop-off and pickup areas on the first level, respectively. Similarly, the lower level port column includes separate drop-off and pickup port columns for transferring storage containers to the drop-off and pickup areas on the second level, respectively. The separate drop-off and pickup port columns may be used to drop off and pick up storage containers between access stations on different levels.For example, the first drop-off port column 506a and the first pickup port column 508a are used to drop off and pick up bins, respectively, at the first floor of access station 520b. Similarly, the second drop-off port column 506b and the second pickup port column 508b are used to drop off and pick up bins, respectively, at the second floor of access station 520c. Each floor of the inventory handling station assembly includes a conveyor system 522b, c to transport bins from the drop-off area to the pickup area via the access station. The second floor access station includes a first transport system 522b on the first floor and a second transport system 522c on the second floor. As with the conveyor systems described above, each conveyor system on the first and second floors includes an entrance conveyor unit at the drop-off area 516a, b, an exit conveyor unit at the pickup area 518a, b, and at least one access conveyor unit at the access station 520b, c. The direction of travel of a bin from an entrance conveyor unit, via at least one access conveyor unit, to an exit conveyor unit is indicated by the arrows shown in Figure 17. The entrance conveyor units on different first and second floors of the inventory handling station assembly extend into the grid framework structure to cooperate with (receive) drop-off columns 506a (first and second drop-off columns) below the track system. Similarly, the exit conveyor units on different floors of the inventory handling station assembly extend into the grid framework structure to cooperate with pickup columns 508a, b (first and second pickup columns) below the track system.

[0069] To prevent the first drop-off port column 506a from colliding with the second drop-off port column 506b when unloading a storage container into the drop-off area on the first floor, the drop-off area 516a on the first floor is laterally offset, i.e., set back, from the drop-off area 516b on the second floor. In this manner, the first drop-off port column 506a can cooperate with the drop-off area 516a on the first floor, and the second drop-off port column 506b can cooperate with the drop-off area 516b on the second floor. Similarly, the pickup area 518a on the first floor is laterally offset from the pickup area 518b on the second floor. In this manner, the first pickup port column 508a can cooperate with the pickup area 518a on the first floor, and the second pickup port column 508b can cooperate with the pickup area 518b on the second floor. The first drop-off port column 506a and the second drop-off port column 506b can then deliver storage bins to the first and second access stations 516a, b on different floors at a much faster rate than if a single access station were used on one floor. Similarly, the first pickup port column 508a and the second pickup port column 508b can transfer storage bins to a grid framework structure, thus increasing the speed of storage bin movement through the first and second access stations on different floors. However, the present invention is not limited to the two access stations shown in FIG. 17; the inventory handling station assembly can include any number of access stations on different floors or heights that can be reached by an operator or robotic device operating on the inventory handling station assembly. To increase the visibility of storage bins on different floors, the access stations 520b, c can have a downward slope, for example, at an angle ranging from 10° to 45° relative to the horizontal. As shown in Figure 17, the inventory handling station assembly comprises a frame structure that supports conveyor systems 522b,c on different levels.Each conveyor unit of the conveyor system may comprise any suitable configuration of belts, chains, and / or rollers well known in the art of conveyor systems. One or more of the rollers of at least one conveyor unit may have an integrated drive motor (not shown), while the remaining rollers may be connected to a drive roller by a belt (not shown), or they may be passive.

[0070] To locate a storage container buried deep within a stack, a robotic load handling device operable on a track system must be commanded to remove one or more storage containers above the target storage container so that the target storage container is exposed for the robotic load handling device to lift the target storage container from its storage column. This operation is commonly known in the art as "digging." The operation may be performed by the same robotic load handling device operable on the grid framework structure or by a separate robotic load handling device assigned to specifically "dig" one or more storage containers from the target storage container for subsequent robotic load handling devices to retrieve the target storage container. The operation time for "digging" the target storage container from the stack can represent a significant portion of the time for processing the target storage container, which involves moving the target storage container to an inventory handling station assembly and then returning the target storage container to the grid framework structure. The target storage container may be returned to its original location in the storage column or relocated to a new location or a new storage column.

[0071] To overcome or reduce the "mining" problem, a grid framework structure according to the present invention includes a second track system 614, as shown in FIGS. 18 and 19 , which track system is the first track system 514. Like the first track system 514 described above, the second track system 614 includes a first set of parallel tracks extending in a first direction and a second set of parallel tracks extending in a second direction, the second direction being substantially perpendicular to the first direction, thus creating a grid pattern for one or more robotic load handling devices to move one or more storage bins on the second track system. The second track system 614 is supported by a plurality of upright columns or upright members to form a second plurality of storage columns 615 for stacking and guiding one or more storage bins between and by the upright columns. The plurality of storage columns below the first track system 514 described above in FIG. 12 are referred to as the first plurality of storage columns 212, 215. The storage bins may be arranged in the first and second plurality of storage columns in a grid framework structure such that frequently requested storage bins due to high demand for items therein may be located in the second plurality of storage columns 615 under the second track system. This allows the frequently requested storage bins to be retrieved by robotic load handling equipment operable on the second track system 614. It is equally relevant in the present invention for frequently requested storage bins to be stored in the first plurality of storage columns 212, 215 under the first track system, while the second plurality of storage columns 615 under the second track system 614 may be used to store less frequently requested storage bins. The first and second plurality of storage columns may comprise the first type storage columns 212 and / or the second type storage columns 215 described above with reference to FIG. 12 . One or more storage columns of the first and second plurality of storage columns may be arranged such that they share the same or a common inventory handling station assembly 504.To enable this to be accomplished, the first track system spans the second track system such that the robotic load handling devices operable on the first track system can transport storage containers to different levels of the inventory handling station assembly without affecting the ability of the robotic load handling devices operable on the second track system to transport storage containers to different levels of the same inventory handling station assembly. Further details of transporting storage containers from the first and second track systems are described below.

[0072] 18, the second track system 614 is at a different height, i.e., a different floor, relative to the first track system 514 in that it is at a different height, i.e., lower than the first track system. The storage volume below the second track system 614 has a lower storage capacity than the storage volume below the track system 514. More storage columns 615, and therefore storage bins, can be accommodated below the track system 514 than below the second track system 614.

[0073] The portions of the grid framework structure comprising the first plurality of storage columns 212, 215 and the second plurality of storage columns 615 may optionally be designated as different temperature zones, e.g., ambient, refrigerated, and / or freezer zones. For purposes of the present invention, refrigerated temperatures cover a range between substantially −25° C. and substantially 0° C., more preferably between substantially −21° C. and substantially −18° C.; refrigerated temperatures cover a range between substantially 0° C. and substantially 4° C.; and ambient-controlled temperatures cover a range between substantially 4° C. and substantially 21° C., preferably between substantially 4° C. and substantially 18° C. The first plurality of storage columns may be designated for storing items requiring a refrigerated environment, and the second plurality of storage columns may be designated for storing items requiring an ambient environment, or vice versa. This is particularly important when fulfilling generally small orders comprising up to 10 items, which are common in small convenience stores. By combining the refrigerated and ambient zones into a single grid framework structure having one portion for the refrigerated zone and one portion for the ambient zone, the grid framework structure is able to accommodate the items necessary to fulfill such small orders.

[0074] One or more robotic load handling devices 30b, c operable on the second track system 614 may be controlled by the same or a separate controller that commands the robotic load handling device on the first track system. One or more of the remotely operable robotic load handling devices on the first and second track systems may be configured to receive instructions from a master controller to retrieve a storage container from a specific storage location within the grid framework structure. Wireless communications and networks may be used to provide a communications infrastructure from the master controller via one or more base stations to the one or more robotic load handling devices operable on the first and second track systems. The controllers in the robotic load handling devices may be configured to control various drive mechanisms that control movement of the robotic load handling devices in response to receiving the instructions. For example, the robotic load handling device may be commanded to retrieve a container from a storage column at a specific location on the first and / or second track systems. The instructions may include various X and Y movements on the first and / or second track systems. Upon reaching the storage column, the lifting mechanism is then operated to grasp the storage container and lift it into a container receiving space of the robotic load handling device for subsequent transport to another location on the first and / or second track systems, commonly known as a drop-off port. The container is lowered to a suitable inventory handling station assembly to allow for removal of the item from the storage container.

[0075] Like the first track system 514, the second track system 614 includes drop-off and / or pickup ports where bots can drop off and / or pick up storage containers so that their contents can be transported to an inventory handling station assembly where they can be accessed from outside the grid framework structure. Columns extending below the drop-off and / or pickup ports toward the inventory handling equipment are referred to as drop-off and pickup port columns, respectively. In addition to upper and lower port columns for transferring storage containers between the first track system and different levels of the inventory handling station assembly, the grid framework structure further includes a second upper level port column extending between the second track system and a first access station on the first level, and a second lower level port column extending between the second track system and a second access station on the second level of the inventory handling station assembly. Like the upper level port column for transferring storage containers between the first track system 514 and the first floor drop-off / pick-up area, and the lower level port column for transferring storage containers between the first track system 514 and the second floor drop-off / pick-up area, the second upper level port column is configured to transfer storage containers between the second track system 614 and the first floor first access station drop-off / pick-up area, and the second lower level port column is configured to transfer storage containers between the second track system 614 and the second floor first access station drop-off / pick-up area. Again, the second upper and lower port columns may each be a single port column for dropping off and picking up storage containers at different drop-off and pick-up areas on the first and second floors, respectively, on the inventory handling station assembly. In other words, a single second upper level port column may be provided at which storage containers are dropped off and picked up at the drop-off and pick-up areas of the first floor first access station.Similarly, a single second lower level port column may be provided at which storage containers are dropped off and picked up at the drop-off and pickup areas of the second access station on the second level. In the particular embodiment shown in Figures 18-20, the second upper level port column comprises separate drop-off and pickup port columns at which storage containers are transferred to the respective drop-off and pickup areas on the first level. Similarly, the second lower level port column comprises separate drop-off and pickup port columns at which storage containers are transferred between the respective drop-off and pickup areas on the second level.

[0076] The conveyor systems 522b, c of the different levels of the inventory handling system assembly, i.e., the entrance conveyor units and exit conveyor units of the first and second levels, extend into the grid framework structure sufficiently to allow the port column of the second upper level and the port column of the second lower level below the second track system 614 to deposit and / or pick up storage bins onto their respective conveyor systems of the different levels. The entrance conveyor units and exit conveyor units of the first and second levels of the inventory handling station assembly extend into the grid framework structure such that the entrance conveyor units of the first level extend to the port columns of the first and second upper levels below the first track system 514 and the second track system 614. This allows one or more robotic load handling devices operable on the first track system 514 and the second track system 614 to deposit storage bins onto the entrance conveyor units of the first and second levels for transport to their respective access stations of the inventory handling station assembly. Similarly, one or more robotic load handling devices operable on the first track system 514 and the second track system 614 can pick up storage containers on the first and second floor exit conveyor units of the inventory handling station assembly.

[0077] FIG. 19 is a front view of an example configuration of a first track system 514 and a second track system 614 on different floors for transporting bots to first and second floor access stations via their respective entrance conveyor units. A first track system on the upper floor is shown transporting bots to the first and second floor entrance conveyor units. The second "lower" floor entrance conveyor unit extends into the grid framework structure to allow bots on the first track system 514 to be transported to the second "lower" floor entrance conveyor unit. Similarly, the first "upper" floor entrance conveyor unit extends into the grid framework structure to allow bots on the second track system 614 to be transported to the first "upper" floor entrance conveyor unit. The same principle applies to the first "upper" and second "lower" floor exit conveyor units, where bins waiting at the exit conveyor units are lifted onto the first track system 514 and second track system 614.

[0078] In the case of a first track system for transporting to different first- and second-floor access stations, FIG. 19 shows at least a portion of the first track system protruding above the second track system to allow one or more of the first track system's grid cells to function as drop-off and pickup ports for bots (robotic load handling devices) operable on the first track system to transfer storage containers between the first track system and the inventory handling station assembly. In this manner, both the first and second track systems can transport storage containers to access stations on different levels of the inventory handling station assembly. FIG. 20 shows a schematic side view of a storage and retrieval system according to the present invention at the edge of the drop-off area of ​​the inventory handling station assembly. The different port columns from the first and second track systems 514, 614 to the drop stations on different levels of the inventory handling station assembly are labeled 506a, 506b, 506c, and 506d in FIG. 20. First track system 514 serves first and second floor drop-off areas of the inventory handling station assembly via drop-off port columns 506a and 506b, respectively. Second track system 614 serves first and second floor drop-off areas of the inventory handling station assembly via drop-off port columns 506c and 506d, respectively. For ease of explanation and to distinguish from the first and second drop-off port columns 506a, 506b of the first track system, drop-off port columns 506c and 506d of the second track system may be referred to as the first and second drop-off port columns of the second track system.

[0079] 20 , for a robotic load handling device operable on a first track system 514 to deliver one or more storage containers to a lower inventory handling station assembly, the first (upper) drop-off port column 506 a and / or the second (lower) drop-off port column 506 b of the first track system can extend through one or more grid cells in the second track system 614. For example, the first drop-off port column 506 a can extend through a grid cell in the second track system 614 to a first access station 520 b of the lower inventory handling station assembly, and / or the second drop-off port column 506 b can extend through a separate grid cell in the second track system 614 to a second access station 520 c of the inventory handling station assembly. It is not necessary for the first drop-off port column 506a of the first track system to extend through a grid cell in the second track system to deliver a storage container to the first access station 520b on the upper level of the inventory handling station assembly. By projecting at least a portion of the first track system 514 above the second track system 614 such that the projection extends sufficiently beyond the end of the second track system, the first drop-off port column 506a can extend directly onto the first access station 520b of the inventory handling station assembly without having to extend into a grid cell of the second track system. However, the protrusion of the first track system 514 may not be long enough for the robotic load handling device on the first track system to transport the storage container directly to the second (lower) access station 520c via the second drop-off port column 506b without transporting it through the grid cells of the second track system 614 as shown in FIG. 20; i.e., the second drop-off port column 506b may need to extend through the grid cells of the second track system 614.In this case, a robotic load handling device operable on the first track system can transport the storage container to a second access station below via a second drop-off port column 506b extending through a grid cell in the second track system.

[0080] The same principles apply when transferring storage containers from the first and second floor pickup areas through their respective pickup port columns towards first track system 514 and second track system 614. In this manner, the first and second track systems and their respective first and second drop-off and pickup port columns share a common inventory handling station assembly.

[0081] Not only is the entrance conveyor unit at the second floor drop-off area 516b below the inventory handling station assembly set back from the first floor to receive storage bins from the first track system, but the entrance conveyor units at the first and second floor drop-off areas 516a,b are laterally displaced so that the portal columns on the upper floor extending from the first track system to the drop-off and / or pickup areas do not interfere with the movement of bots (robotic load handling devices) on the second track system. In this way, storage bins lowered onto the entrance conveyor units on either the first "upper" or second "lower" floors can be transported to their respective access stations on different floors, which can pause to pick up one or more items from the storage bins before being transported to their respective exit conveyor units. Similarly, the exit conveyor units at the first and second floor pick-off areas 518a,b are laterally displaced so that portal columns on the upper floor extending from the first track system to the drop-off and / or pickup area do not interfere with the movement of bots (robotic load handling devices) on the second track system. In the particular embodiment shown in FIG. 17, the length of the access conveyor units on the first floor of the inventory handling station assembly is longer than the access conveyor units on the second floor to allow for the laterally displaceable entrance and exit conveyor units. Displacement of the conveyor systems 522b, 522c on the first and second floors of the access station allows a robotic load handling device operable on the first track system to deliver one or more storage containers to the first and second access stations of the inventory handling station assembly, and allows a robotic load handling device operable on the second track system to deliver one or more storage containers to the first and second access stations of the same inventory handling station assembly.

[0082] The travel direction from the drop-off area to the pickup area via the access station on each of the first and second floors is shown to employ a substantially "U"-shaped track, with the containers being transported to and from the access station in opposite but identical first and third transport directions. The containers are transported along the access station in a second transport direction, which is substantially perpendicular to the first and third transport directions, so that the containers change direction twice as they travel from the drop-off area to the pickup area via the access station. However, other track shapes for the containers from the drop-off area to the pickup area via the access station are applicable to the present invention, in order to enable the containers to be transferred between a first track system on an upper floor and a second track system on a lower floor, which are located on different first and second floors of the access station.

[0083] Although preferred embodiments of the present invention have been described in detail above, it should be understood that various modifications of the storage bins incorporating the different features described above are applicable within the scope of the present invention as defined in the claims. For example, the size of the grid cell openings of the second track system may be similar to the configuration of grid cell openings of the track system described with reference to Figures 8 through 11, with a first portion including small, first-type grid openings and a second portion including a combination of small, first-type grid openings and larger, second-type grid openings. In this manner, the second plurality of storage columns under the second track system can accommodate smaller, first-type storage bins and larger, second-type storage bins. Thus, both small, first-type robotic load handling devices and larger, second-type robotic load handling devices can operate on the second track system. Alternatively, the size of the grid cell openings of the first and second track systems in the embodiment of the present invention shown in Figures 16 through 20 may be uniform, in the sense of accommodating a single size of storage bin. The following is a summary of the claims as originally filed: [1] A storage and retrieval system comprising: A) A grid framework structure, i) a plurality of storage columns for one or more storage containers to be stored in a vertical stack; ii) a track system disposed above the plurality of storage columns, the track system comprising a plurality of tracks arranged in a grid pattern extending substantially in a horizontal plane, the track system comprising a plurality of grid cells or grid spaces along which the storage containers in a stack can be transferred between the plurality of storage columns and an uppermost stage of the track system; a grid framework structure comprising: B) an inventory handling station assembly having a first access station on a first floor and a second access station on a second floor, said first floor being vertically spaced from said second floor for gaining access to the contents of storage containers at said first and second access stations on said first and second floors, respectively; C) an upper level port column extending from said track system to said first access station on said first level for transferring storage containers between said track system and said inventory handling station assembly; D) a lower level port column extending from said track system to said second access station on said second level for transferring containers between said track system and said inventory handling station assembly; A storage and retrieval system comprising: [2] The storage and retrieval system of [1], wherein the first access station is laterally offset from the second access station. [3] The storage and retrieval system according to [1] or [2], wherein the first access station at least partially covers the second access station. [4] the first floor of the inventory handling station assembly includes a drop-off area and a pickup area located below a port column on the upper floor for transferring storage containers between the track system and the first floor drop-off and pickup areas; The storage and retrieval system of any one of [1] to [3], wherein the second floor of the inventory handling station assembly includes a drop-off area and a pickup area located below a port column on the lower floor for transporting storage containers between the track system and the drop-off area and pickup area on the second floor. [5] The storage and retrieval system described in [4], wherein the upper and lower port columns include a drop-off port column for enabling storage containers to be lowered from the track system to the drop-off area and a pickup port column for enabling storage containers to be picked up from the pickup area toward the track system. [6] The storage and retrieval system described in [4] or [5], wherein the drop-off area and the pickup area on the first floor are laterally offset from the drop-off area and the pickup area on the second floor, respectively, such that the drop-off area and the pickup area on each of the first floor and the second floor are positioned below the port column of the upper floor and the port column of the lower floor, respectively. [7] The storage and retrieval system of any one of [4] to [6], wherein the first floor comprises a first conveyor system configured to transport one or more storage containers from the drop-off area to the pickup area via the first access station, and the second floor comprises a second conveyor system configured to transport one or more storage containers from the drop-off area to the pickup area via the second access station. [8] each of the first conveyor system and the second conveyor system comprises an entrance conveyor unit, an exit conveyor unit, and at least one access conveyor unit; the entrance conveyor unit is disposed in the drop-off area and is arranged to convey bins in a first conveyance direction from the drop-off area to the first or second access station; the exit conveyor unit is disposed in the pickup area and is arranged to convey bins from the at least one access conveyor unit to the pickup area in a second conveying direction; [7] The storage and retrieval system described in [7], wherein the at least one access conveyor unit is arranged to transport storage containers from the drop-off area to the pickup area via the first access station or the second access station, respectively, in a third transport direction. [9] The storage and retrieval system described in [8], wherein the entrance conveyor unit and the exit conveyor unit are arranged such that the first conveying direction of the entrance conveyor unit is opposite to and parallel to the second conveying direction of the exit conveyor unit, and the third conveying direction of the at least one access conveyor unit is substantially perpendicular to both the first conveying direction of the entrance conveyor unit and the second conveying direction of the exit conveyor unit.

[10] The storage and retrieval system described in [8], wherein the conveyor system is arranged such that the first conveying direction of the entrance conveyor unit is substantially perpendicular to both the second conveying direction of the exit conveyor unit and the third conveying direction of the at least one access conveyor unit.

[11] The storage and retrieval system of any one of [1] to

[10] , wherein the grid framework structure comprises a first plurality of upright columns arranged to be stacked vertically between a plurality of upright columns to form the plurality of storage columns for one or more of the storage containers to be guided thereby.

[12] The grid framework structure comprises: i) a second plurality of storage columns for one or more storage containers to be stored in a vertical stack; ii) a second track system disposed above the second plurality of storage columns, the second track system comprising a plurality of tracks arranged in a grid pattern extending substantially in a horizontal plane, the second track system comprising a plurality of grid cells or grid spaces through which the storage containers in a stack can be transferred between the second plurality of storage columns and the top stage of the second track system, the second track system being vertically spaced from the first track system such that the second track system and the second track system share the same inventory handling station assembly; iii) a second upper level port column extending from said second track system to said first access station on said first level for transferring storage containers between said second track system and said inventory handling station assembly; iv) a second lower level port column extending from said second track system to said second access station on said second level for transferring containers between said second track system and said inventory handling station assembly; The storage and retrieval system according to any one of [1] to

[11] , further comprising:

[13] The storage and retrieval system of

[12] , wherein the grid framework structure comprises a second plurality of upright columns arranged to be stacked vertically between the upright columns and form the second plurality of storage columns for one or more of the storage containers to be guided thereby.

[14] The storage and retrieval system according to

[12] or

[13] , wherein the track system is above the second track system.

[15] A storage and retrieval system as described in any one of

[12] to

[14] , wherein at least a portion of the track system protrudes into the second track system to enable a robotic load handling device operable on the protrusion to transport storage containers to the inventory handling station assembly.

[16] The storage and retrieval system described in

[15] , wherein the at least a portion of the track system projecting into the second track system comprises the upper level port column for transferring storage containers between the track system and the first access station of the inventory handling station assembly and / or the second lower level port column for transferring storage containers between the track system and the second access station of the inventory handling station assembly.

[17] The track system and / or the second track system are i) a small cell portion comprising a first set of grid cells; ii) a large cell portion comprising a second set of grid cells; and Equipped with at least one dimension of each grid cell of the second set of grid cells is a multiple of at least one dimension of each grid cell of the first set of grid cells; A storage and retrieval system according to any one of

[12] to

[16] .

[18] The storage and retrieval system of

[17] , wherein the second track system comprises the first set of grid cells.

[19] i) the first set of grid cells comprises a first set of parallel tracks extending in a first direction and second and third sets of parallel tracks extending in a second direction, the second direction being substantially perpendicular to the first direction, the first, second and third sets of parallel tracks being arranged in the grid pattern, and each grid cell of the first set of grid cells has a dimension extending in the first direction and a dimension extending in the second direction to define a first type of grid cell opening; ii) the second set of grid cells comprises the first and second sets of parallel tracks, each grid cell of the second set of grid cells having a dimension extending in the first direction and a dimension extending in the second direction to define a second type of grid cell opening;

[17] or

[18] . The storage and retrieval system of

[17] or

[18] , wherein in the first direction, a dimension of the second type grid cell opening is a multiple of the dimension of the first type grid cell opening, and in the second direction, a dimension of the first type grid cell opening is substantially equal to a dimension of the second type grid cell opening.

[20] The storage and retrieval system i) a first type of robotic load handling apparatus comprising a first vehicle wheel assembly comprising a first set of wheels having a first track width and a second set of wheels having a second track width; ii) a second type robotic load handling device operable on the track system, the second type robotic load handling device comprising a second vehicle wheel assembly comprising a first set of wheels having a first track width and a second set of wheels having a second track width; and Furthermore, the first track width of the first vehicle wheel assembly is substantially equal to the first track width of the second vehicle wheel assembly and the second track width of the second vehicle wheel assembly is a multiple of the second track width of the first vehicle wheel assembly, such that the first type of robotic load handling device is capable of moving in both the first direction and the second direction on the first set of grid cells and the second type of robotic load handling device is capable of moving in both the first direction and the second direction on the second set of grid cells; the first type robotic load handling device and / or the second type robotic load handling device are operable on the track system and / or the second track system; A storage and retrieval system according to any one of

[17] to

[19] .

Claims

1. 1. A storage and retrieval system comprising: A) A grid framework structure, comprising: i) a plurality of storage columns for one or more storage containers to be stored in a vertical stack; ii) a track system disposed above the plurality of storage columns, the track system comprising a plurality of tracks arranged in a grid pattern extending in a substantially horizontal plane, the track system comprising a plurality of grid cells or grid spaces along which the storage containers in a stack can be transferred between the plurality of storage columns and an uppermost stage of the track system; a grid framework structure comprising: B) an inventory handling station assembly comprising a first access station on a first level and a second access station on a second level, said first level being vertically spaced from said second level for gaining access to the contents of storage containers at said first and second access stations on said first and second levels, respectively; C) an upper level port column extending from said track system to said first access station on said first level for transferring storage containers between said track system and said inventory handling station assembly; D) a lower level port column extending from said track system to said second access station on said second level for transferring storage containers between said track system and said inventory handling station assembly; A storage and retrieval system comprising: the first level of the inventory handling station assembly including a drop-off area and a pickup area disposed below a port column of the upper level for transferring storage containers between the track system and both the drop-off area and the pickup area of ​​the first level; The second level of the inventory handling station assembly includes a drop-off area and a pickup area located below a port column of the lower level for transferring containers between the track system and both the drop-off area and the pickup area of ​​the second level. 、 a storage and retrieval system, wherein each of the upper level port column and the lower level port column comprises a separate drop-off port column and a separate pickup port column connecting to a respective drop-off area and a respective pickup area, and a transport system for transporting storage containers from the drop-off area to the pickup area via a respective first access station and a respective second access station.

2. 10. The storage and retrieval system of claim 1, wherein said first access station is laterally offset from said second access station.

3. 3. The storage and retrieval system of claim 1 or 2, wherein the first access station at least partially covers the second access station.

4. A storage and retrieval system as described in claim 1 or 2, wherein the first and / or second access stations are tilted downward to increase the presentation of the storage containers on the first and second floors, respectively.

5. 2. The storage and retrieval system of claim 1, wherein the drop-off area and the pickup area of ​​the first floor are laterally offset from the drop-off area and the pickup area of ​​the second floor, respectively, such that the drop-off area and the pickup area of ​​each of the first floor and the second floor are disposed below their respective upper floor port columns and lower floor port columns.

6. 3. The storage and retrieval system of claim 1 or 2, wherein the grid framework structure comprises a first plurality of upright columns arranged to be stacked vertically between and form the plurality of storage columns for one or more of the storage receptacles to be guided thereby.

7. The grid framework structure comprises: i) a second plurality of storage columns for one or more storage containers to be stored in a vertical stack; ii) a second track system disposed above the second plurality of storage columns, the second track system comprising a plurality of tracks arranged in a grid pattern extending in a substantially horizontal plane, the second track system comprising a plurality of grid cells or grid spaces through which the storage containers in a stack can be transferred between the second plurality of storage columns and the top stage of the second track system, the second track system being vertically spaced from the first track system such that the second track system and the second track system share the same inventory handling station assembly; iii) a second upper level port column extending from said second track system to said first access station on said first level for transferring storage containers between said second track system and said inventory handling station assembly; iv) a second lower level port column extending from said second track system to said second access station on said second level for transferring storage containers between said second track system and said inventory handling station assembly; 3. The storage and retrieval system of claim 1 or 2, further comprising:

8. 8. The storage and retrieval system of claim 7, wherein the grid framework structure comprises a second plurality of upright columns arranged to be stacked vertically between the upright columns to form the second plurality of storage columns for one or more of the storage receptacles to be guided thereby.

9. The storage and retrieval system of claim 7 , wherein the track system is above the second track system.

10. 8. The storage and retrieval system of claim 7, wherein at least a portion of said track system projects onto said second track system to allow a robotic load handling device operable on the projection to deliver storage containers to said inventory handling station assembly.

11. 11. The storage and retrieval system of claim 10, wherein the at least a portion of the track system that projects into the second track system comprises the second upper level port column for transferring storage containers between the track system and the first access station of the inventory handling station assembly and / or the second lower level port column for transferring storage containers between the track system and the second access station of the inventory handling station assembly.

12. The track system and / or the second track system i) a small cell portion comprising a first set of grid cells; ii) a large cell portion comprising a second set of grid cells; and Equipped with at least one dimension of each grid cell of the second set of grid cells is a multiple of at least one dimension of each grid cell of the first set of grid cells; 8. The storage and retrieval system of claim 7.

13. 13. The storage and retrieval system of claim 12, wherein said second track system comprises said first set of grid cells.

14. i) the first set of grid cells comprises a first set of parallel tracks extending in a first direction and second and third sets of parallel tracks extending in a second direction, the second direction being substantially perpendicular to the first direction, the first, second and third sets of parallel tracks being arranged in the grid pattern, each grid cell of the first set of grid cells having a dimension extending in the first direction and a dimension extending in the second direction to define a first type of grid cell opening; ii) the second set of grid cells comprises the first and second sets of parallel tracks, each grid cell of the second set of grid cells having a dimension extending in the first direction and a dimension extending in the second direction to define a second type of grid cell opening; 13. The storage and retrieval system of claim 12, wherein in the first direction, a dimension of the second type grid cell opening is a multiple of the dimension of the first type grid cell opening, and in the second direction, a dimension of the first type grid cell opening is substantially equal to a dimension of the second type grid cell opening.

15. The storage and retrieval system i) a first type of robotic load handling apparatus comprising a first vehicle wheel assembly comprising a first set of wheels having a first track width and a second set of wheels having a second track width; ii) a second type robotic load handling device operable on the track system, the second type robotic load handling device comprising a second vehicle wheel assembly comprising a first set of wheels having a first track width and a second set of wheels having a second track width; and Furthermore, the first track width of the first vehicle wheel assembly is substantially equal to the first track width of the second vehicle wheel assembly and the second track width of the second vehicle wheel assembly is a multiple of the second track width of the first vehicle wheel assembly, such that the first type of robotic load handling apparatus is capable of moving in both a first direction and a second direction on the first set of grid cells and the second type of robotic load handling apparatus is capable of moving in both the first direction and the second direction on the second set of grid cells; 13. The storage and retrieval system of claim 12, wherein the first type robotic load handling device and / or the second type robotic load handling device are operable on the track system and / or the second track system.

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