Multi-function inventory handling station assembly

Abstract

An automated inventory handling station 142 suitable for an automated storage and retrieval system, the station having first and second handling positions 48a&b that present storage containers to an o

Description

Technical Field The present disclosure relates to the field of a storage and retrieval system for handling storage containers or bins (otherwise known in the industry as “totes”) stacked in a grid framework structure, more particularly to a multi-function inventory handling station assembly for picking or supplying one or more items or goods to or from the storage and retrieval system comprising the grid framework structure. Background Warehousing and order fulfilment facilities operate on a continual cycle of goods in via decant operations and goods out via order fulfilment operations. Automated storage and retrieval systems (ASRS) are commonly utilized to automate the storage and retrieval processes within such facilities. Decant processes within such facilities commonly include an operator whom picks inbound inventory items from a pallet or unit load and places them in a storage container or tote that is positioned at a decant position of a decant workstation and the tote is subsequently transported to and stored in an ASRS. It is not uncommon for upstream processes (e.g., decant processes) to cause starvation at downstream processes (e.g. pick stations), and it is not uncommon for downstream processes to cause bottlenecking or choking at upstream processes. A typical automated storage and retrieval system comprises a three-dimensional storage grid structure, within which storage containers / bins / totes are stacked on top of each other, are well known. PCT Publication No. WO2015 / 185628A (Ocado) describes a known storage and fulfilment system in which stacks of bins or containers are arranged within a grid framework structure. The bins or containers are accessed by load handling devices remotely operative on tracks located on the top of the grid framework structure. A system of this type is illustrated schematically in Figures 1 to 3 of the accompanying drawings. As shown in Figures 1 and 2, stackable containers, known as totes or bins or containers 10, are stacked on top of one another to form stacks 12. The stacks 12 are arranged in a grid framework structure 14 in a warehousing or manufacturing environment. The grid framework structure comprises a supporting framework structure comprising a plurality of storage columns for storing the storage containers in one or more stacks of storage containers. Each grid in the grid framework structure has at least one storage column for storage of 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 bins 10 arranged within the framework structure 14. Some or all of the storage containers 10 in storage in the grid framework structure may hold a plurality of product items (not shown). The product items within a bin 10 may be identical, or may be of different product types depending on the application. The grid framework structure 14 comprises a plurality of upright members or upright columns 16 that support horizontal members 18, 20. A first set of parallel horizontal grid members 18 is arranged perpendicularly to a second set of parallel horizontal grid members 20 to form a plurality of horizontal grid structures supported by the upright members 16. The members 16, 18, 20 are typically manufactured from metal and typically welded or bolted together or a combination of both. The bins 10 are stacked between the members 16, 18, 20 of the grid framework structure 14, so that the grid framework structure 14 guards against horizontal movement of the stacks 12 of bins 10, and guides vertical movement of the bins 10. To guide the movement of the load handling devices on the grid framework structure the top level of the grid framework structure 14 comprises a track system comprising a plurality of tracks or rails 22 arranged in a grid pattern across the top of the stacks 12. Referring additionally to Figure 3, the rails 22 support a plurality of load handling devices 30. A first set 22a of parallel rails 22 guide movement of the robotic load handling devices 30 in a first direction (for example, an 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, guide movement of the load handling devices 30 in a second direction (for example, a Y-direction), perpendicular to the first direction. In this way, the rails 22 allow movement of the robotic load handling devices 30 laterally in two dimensions in the horizontal X-Y plane, so that a load handling device 30 can be moved into position above any of the stacks 12. A known load handling device 30 shown in Figure 4 and 5 comprises a vehicle body 32 is described in PCT Patent Publication No. WO2015 / 019055 (Ocado), hereby incorporated by reference, where each load handling device 30 only covers one grid space of the grid framework structure 14. Here, the load handling device 30 comprises a wheel assembly comprising a first set of wheels 34 consisting a pair of wheels on the front of the vehicle body 32 and a pair of wheels 34 on the back of the vehicle 32 for engaging with the first set of rails or tracks to guide movement of the device 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 with the second set of rails or tracks to guide movement of the device in a second direction. Each of the set wheels are driven to enable movement of the vehicle in X and Y directions respectively along the rails. One or both sets of wheels can be moved vertically to lift each set of wheels clear of the respective rails, thereby allowing the vehicle to move in the desired direction. The load handling device 30 is equipped with a lifting device or crane mechanism to lift a storage container from above. The crane mechanism comprises a winch, a tether or cable 38 wound on a spool or reel (not shown) and a grabber device 39. The lifting device or crane mechanism comprise a set of lifting tethers 38 extending in a vertical direction and connected nearby or at the four corners of a lifting frame 39, otherwise known as a grabber device (one tether near each of the four corners of the grabber device) for releasable connection to a storage container 10. The grabber device 39 is configured to releasably grip the top of a storage container 10 to lift it from a stack of containers in a storage system of the type shown in Figure 1 and 2. The wheels 34, 36 are arranged around the periphery of a cavity or recess, known as a container-receiving recess 40, in the lower part of the load handling device. The recess is sized to accommodate the container 10 when it is lifted by the crane mechanism, as shown in Figure 5 (a and b). When in the recess, the container is lifted clear of the rails beneath, so that the vehicle or load handling device can move laterally to a different location. Typically, goods or items arriving at the storage and retrieval system on one or more pallets enter the grid framework structure via an inbound area of the storage and retrieval system and leave the grid framework structure after fulfilling one or more customer orders via the outbound area of the storage and retrieval system. Inbound inventory is decanted in an upstream decanting function and the decanted items are stored as inventory in the downstream storage and retrieval system. When an order is placed, the item or items required for that order are released to a picking station at the outbound area where an operator transfers the item to a delivery container. If an item required for the order is not present in the storage inventory, the order must wait or be delayed until more of that required item is decanted and placed into the inventory storage and retrieval system. The movement of goods or items from the inbound area to the outbound area is typically a continuous process as inventory is depleted and replenished from the storage and retrieval system. Upon receipt of a customer order, a load handling device operative to move on the tracks is instructed to pick up a storage bin containing the item of an order from a stack in the grid framework structure and transport the storage bin to a pick station whereupon the item can be retrieved from the storage bin. Typically, the load handling device transports the storage bin or container to a bin lift device that is integrated into the grid framework structure. A mechanism of the bin lift device lowers the storage bin or container to a pick station. At the pick station, the item is retrieved from the storage bin. Picking can done manually by hand or by a robot as taught in GB2524383 (Ocado Innovation Limited). After retrieval from the storage bin, the storage bin is transported to a second bin lift device whereupon it is lifted to grid level to be retrieved by a load handling device and transported back into its location within the grid framework structure. A control system and a communication system keep track of the location of the storage bins and their contents within the grid framework structure. As individual containers are stacked in vertical layers, their locations in the grid framework structure or “hive” may be indicated using co-ordinates in three dimensions to represent the load handling device or a container’s position and a container depth (e.g. container at (X, Y, Z), depth W). Equally, locations in the grid framework structure may be indicated in two dimensions to represent the load handling device or a container’s position and a container depth (e.g. container depth (e.g. container at (X, Y), depth Z). For example, Z=1 identifies the uppermost layer of the grid, i.e., the layer immediately below the rail system, Z=2 is the second layer below the rail system and so on to the lowermost, bottom layer of the grid. When restocking the storage system with items or replenishing the inventory stock of the storage system, items delivered from a supplier is transported to a decant station or a supply station. Here, the items are removed from their packaging and depending on the type of item, registered with a unique stock keeping unit or SKU, and placed in storage bins at the decant station. At the decant station, the storage bins may be transported to a bin lift device whereupon it is lifted to grid level to be retrieved by a load handling device and transported to a location within the grid framework structure. Both fulfilling customer orders and replenishing stock in the storage and retrieval system can be carried in a single station or separate stations. For ease of explanation such stations, the term “inventory handling station” can be used to cover both the pick station and the decant station. In a storage grid, a majority of the grid columns are storage columns, i.e., grid columns where storage containers are stored in stacks. However, a grid framework structure normally has at least one grid column which is used not for storing storage containers, but which comprises a location where the container handling vehicles can drop off and / or pick up storage containers so that they can be transported to a second location where the storage containers can be accessed from outside of the grid or transferred out of or into the grid, e.g. an inventory handling station such as a pick station or a decant station. Within the art, such a location is normally referred to as a “port” and the grid column in which the port is located may be referred to as a “portal” or “port column”. The storage grids comprise two port columns. A first port column may for example comprise a dedicated drop-off port where the container handling vehicles or load handling vehicles can drop off storage containers to be transported through the port column and further to the inventory handling station, and a second port column may comprise a dedicated pick-up port where the container handling vehicles can pick up storage containers that have been transported through the second port column from the inventory handling station. Storage containers are fed into the pick or the decant station via the first port column and exit the inventory handling station via the second port column. A port column dedicated to deliver storage containers to the inventory handling station can be termed a “delivery column” and a port column for the pick up of storage containers from the inventory handling station can be termed a “pick-up column”. WO2017 / 211640 (Autostore Technology AS) describes a storage system for storing product items, comprising a grid structure, a number of storage bins configured to be stored in vertical compartments in the grid structure, where each storage bin is configured to contain at least one product item, where the storage system comprises a picking and / or supply station; and where the storage system comprises a conveyor system configured to convey a storage bin from a first position to a second position and further to a third position. The conveyor system comprises a first, tiltable conveyor configured to convey the storage bin from the first position to the third position via the second position. The picking and / or supply station is provided adjacent to the grid structure. The first and third positions are provided below two different vertical compartments in the grid structure. The tiltable conveyor comprises a hydraulic piston and cylinder mechanism for lowering and elevating a conveyor. The tiltable conveyor supports a storage bin in an inclined position in the second position so allowing items to be manually picked from the storage bin. Once picked, the tiltable conveyor is tilted down and the storage bin is transported to a third position allowing for the storage bin to be retrieved by a load handling device operative on the grid structure. Lowering and elevating rollers using a hydraulic piston and cylinder mechanism not only suffers from alignment issues to make sure that a storage bin is able to be transported from the first position to the third position via the second position but the use of such a tiling device adds a level of complexity to the picking station. WO2018 / 069282 (Autostore Technology AS) describes a picking / supply station assembly for a storage system comprising a grid structure. The picking / supply station assembly comprises a first bin lift device, a second bin lift device and a picking / supply station, wherein the first bin lift device is arrangeable to receive a storage bin from the at least one vehicle at the top level of the grid structure and deliver the storage bin to the picking / supply station. The picking / supply station comprises a bin transport assembly arranged to move the storage bin from the first bin lift device to the second bin lift device; and the second bin lift device is arranged to receive the storage bin from the bin transport assembly and is arrangeable to convey the storage bin to the top level of the grid structure. The bin lift device is arranged in the storage system to receive a storage bin from a vehicle or load handling device at the top level of the grid structure and to convey the bin down in a vertical direction to a supply / picking station arranged at the ground floor in the building wherein the storage system is installed, hi use, a first storage bin is initially placed on the lifting arms at the top level of the grid and lowered towards the first conveyor unit. The space between the lifting arms are wide enough to allow the first conveyor unit to pass between them. During passing, the first storage bin will remain on the first conveyor unit, while the lifting arms enters their lowermost position. The first storage bin is then transported out of the first lifting device by the first conveyor unit. After exit of the storage bin from the first bin lift device, the lifting arms may return to the top level for retrieving a second storage bin. The first and second bin lift devices are integrated into the grid framework structure and therefore, the pick station forms an integral part of the grid framework structure. Decanting into storage containers or bins typically requires that all of the storage bins to be presented to an operator at the inventory handling station. In many storage and retrieval facilities, the inventory handling stations are fed by a single access portal or port. Thus, totes for decant may be buffered either one tote at a time or in a long line of totes making it unknown how long a particular tote will remain on the conveyor and therefore, not only unavailable for order fulfilment but may result in the congestion of goods on pallets at the inbound area waiting to be decanted into totes. These and other factors may contribute to underutilized storage volume in partially filled totes, starvation at downstream processes, and potentially inefficient labour usage as the operator may be required to perform additional tasks before they can decant items into the totes. Summary The present disclosure has mitigated the above problem by providing an automated inventory handling station for an automated storage and retrieval system (ASRS) with multiple handling positions to receive and present storage containers, otherwise known in the industry as “totes” to multiple operators (e.g., human or robotic arm) at the same time from multiple portals or ports of the automated storage and retrieval system and to return the totes into the storage and retrieval system along a single path shared by all of the multiple inventory handling positions. The automated inventory handling station can be an automated decant station or an automated picking station. The station may include one or more buffers adjacent the inventory handling positions to reduce the cycle times when a tote is returned to the ASRS and replaced by another tote upstream of the inventory handling position. For example, once a tote at one of the inventory handling positions has been filled or decanted and transported to the ASRS, the buffered tote is immediately available to move to the open inventory handling position to be decanted or picked. In addition to buffering one or more totes at anyone of the inventory handling positions, the station can include one or more buffer zones adjacent the shared path to return the decanted or picked totes to the ASRS. This reduces the cycle time for a tote to be presented to an operator at one of the inventory handling positions as an operator does need to wait for the tote to be returned to the ASRS before commencing interacting with another tote from the ASRS. This is turn increases the capacity (e.g., decanting or picking) by which the station can interact with totes from the ASRS and thereby, increases the feed rate by which totes can be returned to the ASRS. Thus, having multiple operators at the station increases the rate by which totes can be decanted into or picked from and subsequently return to the ASRS. The automated inventory handling station may be utilised with various forms of automated storage and retrieval systems (ASRS). The automated inventory handling system are particularly well suited to a grid based or cubic based storage system as discussed in the introductory part of the description but can be used in autonomous mobile robot (AMR) based material handling systems. More specifically, an automated inventory handling station is provided for an automated storage and retrieval system, said automated inventory handling station comprising a conveyor system arranged to receive one or more storage containers from the automated storage and retrieval system, said conveyor system comprising: i) a first outflow conveyor comprising a first drop off zone for receiving one or more storage containers from the automated storage and retrieval system and a first inventory handling position configured to present one or more storage containers to an operator such that the operator is able to decant or pick one or more items into or from the one or more storage containers, the first outflow conveyor being arranged to convey the one or more storage containers from the first drop off zone to the first inventory handling position; ii) a second outflow conveyor comprising a second drop off zone for receiving one or more storage containers from the automated storage and retrieval system and a second inventory handling position configured to present one or more storage containers to an operator such that the operator is able to decant or pick one or more items into or from the one or more storage containers, the second outflow conveyor being arranged to convey the one or more storage containers from the second drop off zone to the second inventory handling position; and iii) an inflow conveyor arranged to convey one or more storage containers from the first and second inventory handling positions into the automated storage and retrieval system via a pickup zone; wherein the inflow conveyor is shared between the first and second inventory handling positions. The automated inventory handling station is connected to the ASRS via one or more portals or port columns so that the automated inventory handling station is able to interact with the ASRS to receive and return totes. The automated inventory handling station is not limited to having a first and second outflow conveyor for feeding one or more totes to their first and second inventory positions, the inventory handling station can include a plurality of inventory handling positions which in turn includes a plurality of outflow conveyors for interacting with the totes dropped off from the ASRS. The automated inventory handling station can be an automated decant station such that the first and second inventory handling positions are first and second decant positions respectively or an automated pick station such that the first and second inventory handling positions are first and second pick positions. The inventory handling station can be positioned alongside or below the ASRS. A dedicated conveying system or transportation system can be provided where different portions of the conveyor system provide a first outflow conveyor, a second outflow conveyor and an inflow conveyor, wherein the inflow conveyor is shared between the first and second outflow conveyors. The first and second outflow conveyors transports one or more storage containers from their respective first and second drop-off zones to their respective inventory handling positions and the inflow conveyor transports the one or more storage containers to a position where it can be picked up and returned to the ASRS. Thus, an automated inventory handling station for an automated storage and retrieval system can be provided, said automated inventory handling station comprising a conveyor system arranged to receive one or more storage containers from the automated storage and retrieval system, said conveyor system comprising: i) a first outflow conveyor comprising a first drop off zone for receiving one or more storage containers from the automated storage and retrieval system and a first inventory handling position configured to present one or more storage containers to an operator such that the operator is able to decant or pick one or more items into or from the one or more storage containers, the first outflow conveyor being arranged to convey the one or more storage containers from the first drop off zone to the first inventory handling position; ii) a second outflow conveyor comprising a second drop off zone for receiving one or more storage containers from the automated storage and retrieval system and a second inventory handling position configured to present one or more storage containers to an operator such that the operator is able to decant or pick one or more items into or from the one or more storage containers, the second outflow conveyor being arranged to convey the one or more storage containers from the second drop off zone to the second inventory handling position; and iii) an inflow conveyor arranged to convey one or more storage containers from the first and second inventory handling positions into the automated storage and retrieval system via a pickup zone; wherein the inflow conveyor is shared between the first and second inventory handling positions The conveyor system provides a transportation system for one or more storage containers between the ASRS and their corresponding inventory handling positions. In the case of a gridbased ASRS, the grid framework structure comprises at least one portal or port column for transferring one or more totes between the ASRS and the automated inventory handling station. Instead of returning a picked or decanted tote into the ASRS along the same path the tote arrived into the inventory handling station, the return path into the ASRS is shared between two or more inventory handling positions. This removes the need to having separate conveyor systems to return the picked or decanted totes back into the ASRS thereby reducing the footprint of the inventory handling station. Two or more inventory handling positions can be shared by two or more operators increasing the handling capacity of the inventory handling station. For example, two operators can interact with two totes at the same time and return the interacted totes back into the ASRS along a shared path increasing the handling capacity of the automated inventory handling station to 2:1. This is in comparison to a 1:1 decant station where the ratio of operator interacting with the tote and the return path is only 1:1. Having a first outflow conveyor and a second outflow conveyor, each of the first and second outflow conveyors comprising a drop off zone for receiving one or more storage containers from the ASRS and being arranged to convey one or more storage containers from their respective drop off zones to their first and the second inventory handling positions respectively improves the safety aspect of the inventory handling station as the interaction position with the inventory handling station can be remote from the ASRS. In other words, the first and second inventory handling positions can be located further away from their respective drop off zones from the ASRS. In the case of a grid-based ASRS, a sufficient distance can exist between the drop off zones where the inventory handling station interacts with the ASRS and the operators interacting with the inventory handling station. The first and second outflow conveyors and the inflow conveyor can extend within the grid framework structure such that their respective dropoff zones and pick-u zones are below the track system. Increasing the inventory handling capacity by increasing the density of inventory handling stations close together also places a burden on the operators working too close to another. In the case where the inventory handling station is a decant station, there may be inadequate room or floor space to accommodate one or more pallets of inbound goods if the decant station are placed too close to one another. To mitigate this problem, the first and second outflow conveyors are laterally disposed either side of the inflow conveyor. One way to achieve this is to arrange the inflow conveyor to transport one or more storage container into the ASRS in a direction substantially parallel to the transport direction of the first and / or second outflow conveyors. Preferably, the inflow conveyor is arranged to transport one or more storage container into the ASRS in a direction substantially parallel and opposite to the transport direction of the first and / or second outflow conveyors. To manage the flow of totes along the conveyor system, the automated inventory handling station comprises comprising at least one occupancy sensor for sensing the presence of at least one storage container on at least a portion of the conveyor system. Optionally, the at least one occupancy sensor comprises at least one interaction occupancy sensor for sensing the presence of one or more storage containers at the first and the second inventory handling positions. To share the inflow conveyor between the first and second inventory handling positions, optionally, the inflow conveyor comprises a merge zone arranged to receive one or more storage containers from the first inventory handling position and the second inventory handling position. One or more totes fed from the first and second inventory handling positions can enter the shared inflow conveyor via a merge zone. To prevent totes clashing at the merge zone, the at least one occupancy sensor, optionally, comprises at least one merge occupancy sensor for sensing the presence of one or more storage containers at the merge zone. For example, a tote is not allowed to be transported to the merge zone if the at least one merge occupancy sensor senses that there is a tote waiting at the merge zone. Once the merge zone is clear, a tote upstream of the merge zone is immediately available to enter the open merge zone. To reduce the waiting times for a decanted or picked tote at their respective inventory handling positions, optionally, the conveyor system further comprises a buffer zone for temporarily storing one or more storage containers prior to being transported to the merge zone, said buffer zone being adjacent the first and / or second inventory handling positions. One or more totes can be buffered upstream of the inventory handling positions towards the drop-off zones or downstream of the inventory handling positions towards the merge zone where the totes are presented to the operators. By buffering one or more totes upstream of the inventory handling positions increases the flow rate of totes being dropped-off at the drop-off zones from the ASRS. In the case of a grid based ASRS, such increased flow rate mitigates the congestion at the ports where one or more load handling devices are waiting to drop off one or more totes to the inventory handling station via their respective drop off zones. Equally, by buffering one or more totes upstream of the inventory handling position clears the space at the inventory handling position to receive a buffered tote and thereby, prevents the clash of totes at the merge zone. Ultimately, buffering one or more totes upstream and / or downstream of the first and second inventory handling positions increases the capacity by which the automated inventory handling station can handle totes from the ASRS. To buffer one or more totes adjacent the merge zone, optionally, the buffer zone is intermediate or between the first inventory handling position and the merge zone. Optionally, the at least one occupancy sensor comprises at least one buffer occupancy sensor for sensing the presence of one or more storage containers at the buffer zone. To free up the merge zone for a buffered tote to enter the merge zone, optionally, the at least one occupancy sensor comprises at least one pick-up zone occupancy sensor for sensing the presence of one or more storage containers at the pick-up zone. To manage the flow the totes along the conveyor system, optionally, the automated inventory handling station comprising a control system comprising one or more processors and memory storing instructions that when executed by the one or more processors control the conveyor system control the flow of one or more storage containers along the at least portion of the conveyor in response to one or more signals from the at least one occupancy sensor. Thus, to determine the presence of one or more totes at the first and / or second inventory handling positions and thereby, improve the flow of the one or more totes along the conveyor system, the warehouse control system is configured to instruct the conveyor system to convey one or more storage containers to the first and / or second inventory handling positions from their respective drop-off zones in response to receiving to one or more signals from the at least one interaction occupancy sensor. Optionally, the warehouse control system is configured to convey one or more storage containers from the buffer zone to the merge zone and / or from the first inventory handling position to the buffer zone and / or from the drop-off zone to the first inventory handling position in response to one or more signals from the at least one buffer occupancy sensor. Optionally, the warehouse control system is configured to convey one or more storage containers from the merge zone to the pick-up zone in response to one or more signals from the at least one pick-up zone occupancy sensor. Optionally, the conveyor system comprises one or more right angle transfers (RATs) for transporting one or more totes from their respective drop-off zones at the first and second outflow conveyors to the pick-up zone at the inflow conveyor. For example, the transition from the first and second outflow conveyors to the inflow conveyor may comprise one or more right angle transfers (RATs). The RATs can be incorporated into the conveyor system and can optionally comprises but is not limited to pop-up transfers and turn post transfers. In another aspect, the ASRS is provided in the form of a grid-based storage system and the inventory handling station is fed one or more totes lowered from the grid-based storage system. An automated storage and retrieval system is therefore provided, the automated storage and retrieval system comprising: A) an automated inventory handling station as defined herein; B) a grid framework structure comprising a track system comprising a plurality of tracks arranged in a grid pattern comprising a plurality of grid cells for guiding the movement of one or more load handling devices on the grid framework structure, and a supporting framework structure comprising a plurality of storage columns being arranged below the track system and arranged to accommodate one or more stacks of storage containers and at least one port column through which one or more storage containers can be dropped off and picked up from the conveyor system of the automated inventory handling station. Optionally, the at least one port column comprises first and second drop off columns and a pick-up column, said first and second drop off columns being arranged to drop off one or more storage containers to the drop-off zones of the first and second outflow conveyors respectively and the pick-up column being arranged to pick-up one or more storage containers from the pick-up zone. Optionally, the first and second outflow conveyors extends into the first and second drop off columns respectively such that their respective drop-off zones are within the grid framework structure, i.e., below the track system. Equally, the inflow conveyor extends in to the pick-up column such that the pick-up zone is within the grid framework structure, i.e., below the track system. As a result, the first and second outflow conveyors and the inflow conveyor extends from a position within the grid framework structure to a position outside of the grid framework structure. Optionally, the automated storage and retrieval system comprises a plurality of load handling devices operatable on the track system, each of the plurality of one load handling devices comprising: a) a driving assembly configured to move the load handling device on the track system; b) a grabber device configured to releasably hold a storage container from above; and c) a lifting assembly through which the grabber device can drop off to and pick-up storage containers from the conveyor system via the at least one port column. Optionally, the warehouse control system operable to instruct one or more of the plurality of load handling devices to deliver one or more storage containers from the grid framework structure to the automated inventory handling station. A method is provided of controlling the flow of one or more storage containers between an automated storage and retrieval system and an automated inventory handling station as defined herein, the method comprising the steps of: i) presenting a first storage container to a first operator at the first inventory handling station; ii) presenting a second storage container to a second operator at the second inventory handling station; iii) returning, by the conveyor system, the first storage container and / or the second storage container to the automated storage and retrieval system by determining the presence of one or more containers at the inflow conveyor. To increase the capacity of the automated inventory handling station for handling totes, the method further comprises the step of buffering one or more storage containers on at least a portion of the conveyor system. As the inflow conveyor is shared between the first and second outflow conveyors, the method further comprises the step of sensing the presence of one or more storage containers on at least portion of the conveyor system and in response to sensing the presence of the one or more storage containers on the at least portion of the conveyor system buffering the one or more storage containers on the at least a portion of the conveyor system. Detailed Description Further features and aspects will be apparent from the following detailed description of an illustrative embodiment made with reference to the drawings, in which: Figure lisa schematic diagram of a grid framework structure according to a known system, Figure 2 is a schematic diagram of a top down view showing a stack of bins arranged within the framework structure of Figure 1. Figure 3 is a schematic diagram of a system of a known load handling device operating on the grid framework structure. Figure 4 is a schematic perspective view of the load handling device showing the lifting device gripping a container from above. Figure 5(a) and 5(b) are schematic perspective cut away views of the load handling device of Figure 4 showing (a) the container receiving space of the load handling device and (b) a container accommodating the container receiving space of the load handling device. Figure 6 is a perspective view of an automated inventory handling station according to one example. Figure 7 is a perspective view of an automated inventory handling station showing additional buffering on the conveyor system according to a second example. Figure 8 is a perspective view of an automated inventory handling station showing additional buffering of the totes on the conveyor system according to a third example. Figure 9 is a perspective view of the automated inventory handling station shown in Figure 7 connected to a grid-based ASRS. Figure 10 is a perspective view of the automated inventory handling station shown in Figure 8 connected to a grid-based ASRS and the operators interacting with the automated inventory station being a robotic manipulator. Figure 11 is a perspective view of a series of inventory handling stations shown in Figure 8 for increasing the inventory handling capacity of an ASRS. Figure 12 is perspective view of the series of inventory handling stations shown in Figure 11 from a different perspective. Figure 13 is schematic plan view of the arrangement of a series of conveyor units forming the conveyor system of the inventory handling station of Figure 7. Figure 14 is a flowchart showing the steps of moving a storage container from the drop off zone to the pick-up zone through the automated inventory handling station. Detailed Description It is against the known features of the storage system such as the grid framework structure and the robotic load handling device described above with reference to Figures 1 to 5, the present disclosure has been devised. Figures 6 to 8 show different examples of the automated inventory handling stations 42. The different examples of the automated inventory handling stations 42, 142, 242 are configured to interact with an ASRS to receive and feed one or more totes in a continuous cycle between the ASRS and the automated inventory handling station 42, 142, 242. In the illustrative examples shown in Figure 9, the ASRS is shown as a grid-based storage and retrieval system 1 comprising one or more portals or port columns 44a, 44b, 46 for feeding and receiving one or more totes from the ASRS 1 discussed in the introductory part of the present description to the automated inventory handling station 42. It will be appreciated that while the ASRS is described as a grid-based storage and retrieval system, the automated inventory handling station can be adapted to interact with other forms of ASRSs. These include but is not limited to an aisle-based storage and retrieval systems, a rack-based storage and retrieval system operated with an automatic guided vehicle (AGVs) or autonomous mobile robot (AMR) or other material handling system known in the art. In all cases, one or more totes are fed to the automated inventory handling station via one or more portals or port columns of the ASRS. In all of the different examples of the automated inventory handling stations 42,142, 242 shown Figures 6 to 8, the automated inventory handling station comprises a plurality of presentation or interaction positions 48a, 48b for a plurality of operators 50a, 50b to interact with the automated inventory handing station 42, 142, 242. In the particular example shown in Figure 6 to 8, each of the automated inventory handling stations 42, 142, 242 comprises a first handling position 48a and a second handling position 48b. For the purpose of the present disclosure, the phrase “interaction position”, presentation position” and “inventory handling position” are used interchangeably in the description to provide the same function of an operator interacting with the automated inventory handling station. The interaction with the automated inventory handling station includes but is not limited to decanting one or more items into one or more totes from one or more pallets to replenish inventory stock in the ASRS or picking one or more items from one or more totes delivered from the ASRS into one or more delivery totes for fulfilling one or more customer orders. For ease of explanation, the automated inventory handling station will be described in the context of an automated decant station but it will be appreciated that the automated inventory handling station can be operated as an automated picking station comprising a plurality of picking positions for decanting into a plurality of delivery containers. The automated inventory handling station 42, 142, 242 comprises a transportation or conveyor system 52 (see Figure 13) for moving one or more totes between the ASRS and the inventory handling positions 50a, 50b of the inventory handling station. Typically, in the art, the conveyor system is arranged such that there is a 1:1 relationship between the ASRS and the operator interaction positions in the sense that are totes fed into the inventory handling station from the ASRS for decanting or picking by an operator is subsequently returned to the ASRS along the same or a single path. The problem with such an arrangement of the conveyor system is the inefficiencies of replenishing stock in the ASRS due to having only a single port for feeding and receiving totes between the ASRS and the inventory handling station resulting in delays in cycling one or more totes between the ASRS and the inventory handling station. Even if multiple ports are present in the ASRS to deliver totes to the inventory handling station, the ports typically require separate independent stations to deliver the totes. Multiple ports 54a, 54b, 56 of the ASRS lead to a single inventory handling station so as to enable multiple operators at multiple inventory handling positions to each receive one or more totes simultaneously (see Figure 10). For a grid-based storage and retrieval system shown in Figures 6 to 8, the automated inventory handling station can comprise one or more chutes 58a, 58b, 60 for a load handling device 30 operative on the grid framework structure 14 to lower a tote onto the conveyor system. This could be under the action of gravity where the tote is allowed to descend down the chute under the weight of the tote and / or being lowered by the lifting or winch mechanism of the load handling device. The one or more chutes can be configured to cooperate with one or more portals or port columns of the grid framework structure, more specifically, the supporting framework structure. The number of port columns is dependent on the number of inventory handling positions at the automated inventory handling station. In the particular example shown in Figure 9, the automated inventory handling station cooperates with first and second port columns for dropping off one or more totes to the automated inventory handling station. The first and second port columns can be termed first and second drop-off columns 44a, 44b. One or more totes dropped off at the automated inventory handling station are returned to the ASRS via an additional port column. To differentiate from the drop-off columns 44a, 44b, the port column for returning the one or totes to the ASRS can be termed pick-up column 46. One or more of the multiple inventory handling positions can be manned by an operator such that the operator may decant inventory items into totes at the one or more of the multiple inventory handling positions from a pallet of inbound goods 62. Similarly, the operator may pick one or more items from totes delivered at the one or more of the multiple inventory handling positions and place them into one or more delivery totes nearby. In both cases, the pallet of inbound goods or the delivery totes for outbound are easily accessible to an operator from their respective inventory handling positions. The conveyor system 52 can be supported on a frame (not shown) for accommodating the drive units and other auxiliary components of the inventory handling station such as the programmable logic controller. Cladding or panelling 64 can be mounted externally of the frame and / or above conveyor system to protect the operators from moving parts of the inventory handling station. The cladding or panelling 64 can have one or more openings 66 in the vicinity of inventory handling positions 48a, 48b so as to provide access to the interior of the totes 10 presented to the operator 48a at the inventory handling positions. Whilst the operators shown in Figures 6 to 9 are depicted as human operators 48a, it will be appreciated that the operator can be an automated operator or a robotic based operator 50a, 50b such as a robotic manipulator comprising a robotic arm. The automated inventory handling station shown in Figure 10 is an example where each of the inventory handling positions are manned a robotic arm 50a, 50b to fully automate the decanting or picking of items to or from the totes presented at each of the inventory handling positions. As will be discussed further below, the conveyor system 52 is arranged such that their inventory handling positions are sufficiently far apart for multiple operators to interact with the automated inventory handling station. The automated inventory handling stations depicted in the examples shown in Figure 6 to 9, comprises two decant positions 48a, 48b that can be interacted or manned by two operators, each of the two decant positions being configured to receive a tote 10 from the ASRS via a portal or port column 44a, 44b and present it to the operator. In the case where the automated inventory handling station comprises two inventory handling positions as shown in Figures 6 to 9, each of the two inventory handling positions receives one or more totes from the ASRS via first and second drop-off columns 44a, 44b. For ease of explanation, the two inventory handling positions at the inventory handling station can be termed first and second inventory handling positions 48a, 48b. In the case, where the automated inventory handling station is an automated decant station, the first and second inventory handling positions can be termed first and second decant positions. Likewise, where the automated inventory handling station is an automated pick station, the first and second inventory handling positions can be termed first and second pick positions. Having multiple inventory handling positions, in this case, first and second decant or pick positions, enable the automated inventory handling station to dedicate each of the inventory handling positions to separately receive differently treated totes so as to cater for different types of goods. In other words, the first inventory position 48a can be arranged to receive totes of a first type and the second inventory position 48b can be arranged to receive totes of a second type. For example, flammable goods such as. oils, batteries, alcohol, deodorants etc may need to be stored in lined totes to improve the fire safety of the ASRS. Equally, some goods such as grocery goods may need to be stored in lined totes to mitigate contamination from the totes and thus, to improve food safety. Different types of totes can be fed to the different inventory handling positions of the automated inventory handling station. For example, lined totes can be fed to the first decant position for decanting flammable items or grocery items and non-lined totes can be fed to the second decant position for decanting ordinary items that are not flammable or sensitive to contamination. Optionally, the liner can comprise a food grade plastic material and / or cellulose base material. To make the cellulose material resistant to moisture and / or oils, optionally, the cellulose can be coated or impregnated with a wax material. Optionally, the cellulose material is paper or cardboard. For fire resistance, the liner, e.g., cellulose material, can be impregnated with an intumescent material or a fire suppressant material. Once decanted at the first and second decant positions, the decanted totes at the first and second decant positions 48a, 48b are returned to the ASRS via a portal or port column 46. Totes decanted at the first and second decant positions are returned or fed into the ASRS via a single tote pick-up position 72 that is shared between the first and second decant positions. Once at the pick-up position, the decanted totes are fed or returned into the ASRS via a portal or port column. To differentiate between the separate drop-off columns for feeding totes to the inventory handling positions, the portal or port column for returning the totes back into the ASRS via the tote pick-up position can be termed a pick-up column 46. The conveyor system or transportation system is configured to transport totes from drop-off positions 70a, 70b via their respective drop-off columns 44a, 44b to their respective inventory handling positions 48a, 48b (decant positions) and subsequently to the tote pick-up position 72 to be returned to the ASRS via the pick-up column 46. In the grid based ASRS, one or more robotic load handling devices operable on the track system is instructed to lower one or more totes onto the conveyor system to be transported to their respective decant positions. The decanted totes are subsequently transported to the tote pick-up position of the conveyor system to be picked up by a robotic load handling device operable on the track system via the pick-up port column and placed in storage in the grid framework structure. The conveyor system can comprise one or more right angle transfer (RATs) 68 for moving totes between the drop-off positions to their respective decant positions and subsequently, to the tote pick-up position (see Figure 13). To transport one or more totes from the drop-off positions 70a, 70b to the tote pick-up position 72 via their respective decant positions 48a, 48b, the conveyor system 52 comprises multiple outflow conveyors for presenting a tote to an operator, each of the multiple outflow conveyors being configured to move one or more totes from their respective drop-off position 70a, 70b to their respective decant position 48a, 48b such that an operator manning the decant position can transfer one or more items from a pallet of inbound goods to a tote. The conveyor system may comprise a plurality of conveyor units C101 - Cl 13 (see Figure 13), each of the conveyor units comprising a conveyor drive unit to transport one or more totes along the conveyor system. Each conveyor unit may comprise any suitable arrangement of belt(s), chain(s) and / or rollers well known in the art of conveyor systems. Typically, for a grid-based ASRS the totes can be rectangular such that they are longer than they are wide. The totes can be transported along the conveyor system such that they are orientated with their long side or their short side being presented to the operator at the decant position. In the examples shown in Figure 6 to 8, the multiple outflow conveyors comprise a first outflow conveyor 76a and a second outflow conveyor 76b, each of the first and second outflow conveyors being configured to move one or more totes from their respective drop-off zones 70a, 70b to their respective decant positions 48a, 48b. Each of the first and second outflow conveyors 76a, 76b can comprise a conveyor drive unit for moving the one or more totes from their drop-off position to their respective first and second decant positions or optionally, a single conveyor drive unit can be configured to move the one or more totes along each of the first and second outflow conveyors. The direction of movement of the totes along the outflow conveyors 76a, 76b to their respective decant positions is shown by the arrows in Figures 6 to 9. In contrast to the inventory handling stations in the art, the route or path to return the decanted totes back into the ASRS from the first and second decant positions is shared between the first and second outflow conveyors 76a, 76b. While the illustrative example is depicted as having first and second outflow conveyors 76a, 76b for presenting totes to the first and second decant positions 48a, 48b respectively, it will be appreciated that more outflow conveyors for feeding respective decant positions may be provided at the inventory handling station without substantially affecting the advantages and functions of the inventory handling station. In addition to the multiple outflow conveyors, the conveyor system additionally comprises an inflow conveyor 78 for returning the decanted totes back into the ASRS via the tote pick-up position 72. The inflow conveyor 78 is shared between the multiple outflow conveyors 76a, 76b. In the case of the illustrative examples shown in Figures 6 to 9, the inflow conveyor 78 is shared between the first and second outflow conveyors 76a, 76b. Thus, decanted totes leaving their respective decant positions are returned back to the ASRS via a shared inflow conveyor 78. Like the outflow conveyor, the inflow conveyor can comprise a conveyor drive unit for moving one or more totes along the inflow conveyor or optionally, a single conveyor drive unit can be configured to move the one or more totes along the outflow conveyor. The movement of the totes along the outflow conveyors and the inflow conveyor are shown by the arrows in Figures 6 to 9. To manage the flow of totes through the automated inventory handling station 42, 142, 242, the automated inventory handling station comprises at least one occupancy sensor (not shown) for sensing the presence of one or more totes on at least a portion of the conveyor system 52. The at least one occupancy sensor can be an optical based sensor, e.g., a laser sensor, or a load bearing sensor that senses the weight of a tote on a part of the inflow conveyor comprising the merge zone. Separate occupancy sensors can be used to manage the flow of totes along different portions of the conveyor system. The different portions of the conveyor system can be the first, second outflow conveyors 76a, 76b and the inflow conveyor 78. If any one of the occupancy sensors senses the presence of a tote on at least portion of the conveyor system, the conveyor system can be instructed to temporarily hold a tote or pause the movement of a tote until the path is clear for the tote to move along the conveyor system. One or more decanted totes exiting one or more of the outflow conveyors, enter the inflow conveyor via a merge zone or merge position 74 of the inflow conveyor as shown in Figure 13. From the merge zone 74, the tote is moved by the inflow conveyor to the tote pick-up position whereupon the decanted tote is returned to the ASRS. Entry of the decanted totes into the merge zone 74 is very much dependent on whether the merge zone is occupied by a tote. To prevent one or more totes exiting the first and second decant positions clashing with a tote occupying the merge zone, the at least one occupancy sensor comprises at least one merge occupancy sensor to sense the presence of a tote occupying the merge zone. The automated inventory handling station comprises a control system comprising one or more processors and memory storing instructions when executed by the one or more processors is configured to control the conveyor system, in particular, the conveyor drive unit, to move one or more totes along the conveyor system, e.g., programmer logic controller (PLC). The control system can be configured to manage the movement of one or more totes along the conveyor system in response to one or more signals from the at least one occupancy sensors. Optionally, the ASRS can comprises a control system and the control system can be communicatively coupled to the control system of the automated inventory handling station via a communication network over a wireless transmitter / receiver (not shown). The communication network, for example, can be a local area network (LAN), a wide area network (WAN) or any other type of network. For example, the automated inventory handling station can comprise a control system which receives control signals from a radio communications unit of the control system of the ASRS. The one or more processors of the control system can execute instructions stored in the ROM and / or RAM to control the movement of conveyor system via one or more conveyor drive units. Alternatively, the operation of directing the decanting or picking operations between the ASRS and the automated inventory handling station can be carried out by the same control system. For ease of explanation, the control system of the automated inventory handling station and the ASRS can be termed a warehouse control system (WCS). The WCS can be operable to control the transportation of totes between the ASRS and the corresponding decant positions of the automated inventory handling station. The WCS is operable to direct the decanting operations at the automated inventory handling station to guide the operator to pick each inbound item from a pallet nearby and place it into a tote at the first or second decant positions. The WCS may comprise a graphical user interface (GUI) or other user interface 80 known in the art to interact with WCS at the inventory handling station. The WCS via the user interface 80 may guide an operator at the respective first and / or second decant positions to transfer one or more items from a nearby pallet to a tote at the first and / or second decant positions. An operator at the first and / or second decant positions retrieves an item from an inbound inventory, e.g., on a pallet, and may scan the picked item or the automated inventory handling station may include optical devices, e.g. barcode reader, to determine the item which the operator has picked. Once the tote at the first and / or second decant positions are appropriately filled with items to replenish stock in the ASRS, the operator may signify the WCS to return the tote into the ASRS. The WCS can also be operable to direct the ASRS to retrieve and transfer totes from the ASRS to the appropriate drop-off column of the inventory handling station so that partially filled or empty totes may be filled with inbound inventory for storage in the ASRS. For example, the WCS can be operable to direct the ASRS to transfer a tote to the appropriate drop-off columns depending on the type of the tote, e.g., lined or non-lined tote, to be decanted into at the first and second decant position which in turn is dependent on the type of inbound inventory goods at the first and second decant positions. In the case of a grid-based ASRS, the WCS can be configured to instruct one or more load handling devices operable on the track system to retrieve one or more storage totes to be decanted into or picked at the automated inventory handling station. For example, when fulfilling an order for multiple different items, the warehouse control system is configured to retrieve multiple storage totes for each of the multiple different items identified in the order. The WCS can be operable to monitor a pending order list of orders to be fulfilled within the warehouse facility housing the ASRS to determine whether inventory items within a tote stored in the ASRS will be required for an in-progress order or an order that will be fulfilled within a user-defined period. In this manner, the WCS may selectively call for the retrieval and transport of totes to the decant workstation. This is to ensure that required items already in the ASRS are readily retrievable when necessary to fulfil a customer order. In operation, a tote 10 decanted at the first or the second decant position 48a, 48b waits until the WCS receives a response from the at least one merge occupancy sensor indicating that the merge zone 74 is clear to receive a tote. In response to a signal from the at least one merge occupancy sensor, the WCS instructs the conveyor system via the conveyor drive unit to move a decanted tote from the first or second decant positions to the merge zone. The user interface 80 discussed above in response to the at least one merge occupancy sensor can be used to guide an operator at the first or second decant positions to move the tote to the merge zone. Preference over whether to send a decanted tote from first or the second decant positions to the merge zone could be dependent on whether an operator has filled a tote with one or more inventory items at the first or second decant positions. For example, in response to the at least one merge occupancy sensor indicating a free space at the merge zone, the first decant position takes priority over the second decant position to move the decanted tote to the merge zone if the operator at the first decant position has completed a decanting operation faster than an operator at the second decant position. The speed by which an operator can decant or pick one or more items into a tote at the inventory handling position can be very much dependent on type of items being decanted into or picked and of course, the picking speed of the operator at the first and second decant positions. For example, smaller items tend to take longer to pick than larger items to fill a tote as larger item requires fewer number of picks. The use of robotic manipulating devices such as robotic arms as operators at one of the first and second decant positions may have a different picking speed than a human operator and can very much dependent on the dexterity of the operator. Human operators tend to have greater dexterity than robotic manipulators to pick complicated or awkward shaped objects but the roles may change due to advancement of robotic arm technology, particularly, end effector technology. Alternatively, preference to move totes from the first inventory position to the merge zone over the second inventory handling position may depend on the availability of inbound inventory items at the first or second decant positions or the immediate requirement of the items for fulfilling one or more customer orders. However, to increase the flow of totes from the first and second inventory handling positions and to prevent disruption at the first and the second inventory handling positions, the totes for decanting or picking may be buffered either one tote at a time or in a long line of totes from the first or second inventory handling positions. Thus, an operator at each of the first and / or second inventory handling positions are continuously presented with at least one tote removing any downtime that an operator has to wait to be presented with a tote. In the particular example of the inventory handling station shown in Figure 7 and 8, the conveyor system comprises one or more buffer zones or positions 82 adjacent the first or second inventory positions. The buffer zones 82 can be individual conveyor units and are labelled C102, C103, C105, C108, C107, Cl 11, and Cl 12 in Figure 13. This could involve buffering one or more totes upstream and / or downstream of the first and / or second decant positions 48a, 48b. Having one or more buffer zones or positions 82 adjacent the first and / or second inventory positions mitigates inefficiencies at the first and second inventory positions for decanting or picking items and thereby, reduces cycle times when a tote is returned to the ASRS and replaced by another tote. In other words, the one or more buffer zones reduces the probability that any one of the conveyor units being left unoccupied for any length of time. For example, additional totes may be buffered downstream of the drop-off positions along the first and / or second outflow conveyors to free up the drop-off positions for a tote to be dropped off from the ASRS and thereby, prevent congestion at the ports leading to the drop-off columns. The warehouse control system discussed above can control the buffering of the one or more totes upstream and / or downstream of the first and / or second decant positions prior to being returned to the ASRS to increase the capacity by which the automated inventory handling station can handle totes. Figure 13 is a drawing showing a plan view of the arrangement of the conveyor system comprising a plurality of conveyor units shown in Figure 7 and 9 according to an exemplary embodiment. The drop-off zones of the first and second outflow conveyors are referenced in Figure 13 as C101 and Cl06 respectively. Each of the conveyor units can be configured to accommodate a single tote or one or more totes. The buffer zone 82 can be a single conveyor unit for accommodating a single tote. In operation with reference to Figures 7 and 9 and the flowchart shown in Figure 14, one or more load handing devices operable on the track system is / are instructed to drop off a tote for decanting at Drop-off Zone 1 and Drop-off Zone 2 84a, 84b. Figures 13 and 14 show the flow of totes along two streams (first and second outflow conveyors) from Drop-off Zone 1 and Drop-off Zone 2 to their respective first and second decant positions (labelled as M104-Interaction position and M109-Interaction position). Movement of the tote to the first second decant positions is dependent on whether the first and second decant positions are occupied by a tote, i.e., free to accommodate a tote. As with the merge zone, the inventory handling station can additionally comprise at least one occupancy sensor for sensing the presence of a tote at each of the first and second decant positions. To differentiate from the at least one occupancy sensor for sensing the presence of a tote at the merge zone, the at least one occupancy sensor for sensing the presence of a tote at the first and second decant positions can be termed at least one interaction occupancy sensor. In response to one or more signals from the at least one interaction occupancy sensor, the warehouse control system determines whether to instruct the conveyor system to move the tote to each of the first and / or second decant positions 86a, 86b. If a tote is occupying each of the first and / or second decant positions, then the warehouse control system will instruct the conveyance system to cause the tote to be held at its current position until the first and / or second decant positions is unoccupied otherwise the tote is moved to their respective first and second decant positions 88a, 88b. At the first and second decant positions 88a, 88b the operator at each of the first and second decant positions decants one or more inventory items into totes presented to the operator 90a, 90b. To free up space at the drop-off positions, one or more totes can also be buffered downstream of the drop-off positions. This is shown in Figures, 7, 9 and the layout of the conveyor system in Figure 13 by having one or more additional conveyor units downstream of the drop-off positions to the first and second decant positions along their respective first and second outflow conveyors. Each of the conveyor units can monitored by at least one occupancy sensor to determine the presence of a tote on their respective conveyor unit before a buffered tote is immediately available to move downstream of the conveyor system to an open conveyor unit. In the example shown in Figure 13, two conveyor units C102 and C103, C107 and C108 are shown between the drop-off positions 70a, 70b and the decant positions 48a, 484b along each of the first and second outflow conveyors 76a, 76b respectively to provide additional buffering of the totes downstream of the drop off positions 70a, 70b. Thus, once a tote at one of the first and / or second decant positions has been filled and transported to the inflow conveyor 78 to be returned to the ASRS, a buffered tote is immediately available to move the tote to the open decant position. In comparison to the arrangement of the conveyor system shown in Figure 6, to reduce the time by which a tote is held at one of the first and / or second decant positions and thereby, increase the rate by which a tote at the first and / or second decant positions can been filled, one or more totes can be buffered downstream of the first and / or second decant positions. In the particular examples of the conveyor system shown in Figures 9 and 10, the conveyor system comprises one or more buffers in the form of conveyor units, C105, downstream of the first and / or second decant positions. Figure 7 shows an example where each tote can be buffered downstream of the first decant position 48a only prior to being moved to the merge zone and Figure 9 shows an example where each tote can be buffered downstream of the first and second decant positions prior to being moved to the merge zone 74. Figure 13 show the arrangement of the conveyor units shown in Figure 7. The buffer zone 82 between the first decant position 48a and the merge zone 74 is labelled in Figure 13 as C105. Movement of a tote to the buffer zone is dependent on whether a tote is occupying the buffer zone 92, 94. As discussed above, at least one occupancy sensor senses the presence of a tote at the buffer zone 82 and in response to one or more signals from the at least one occupancy sensor, the WCS instructs a decanted tote to move into the buffer zone 82. Once a tote has been filled at the first and / or second decant positions the tote can be moved to the buffer zone so that a buffered tote is immediately available to move to the open first decant position. In addition to buffering one or more totes upstream and downstream of the first and / or second decant positions, one or more totes can, optionally, be buffered downstream to the merge zone towards the pick-up zone. This is shown in Figure 13 as two conveyor units, Cl 11, Cl 12, between the merge zone 74 and the pick-up zone 72. In all of the examples, occupancy of the buffer zone can be determined by at least one occupancy sensor discussed above. This can be termed at least one buffer occupancy sensor to differentiate from the other occupancy sensors discussed above. In addition to monitoring the occupancy of the drop-off zones, inventory handling positions (decant or picking) and the buffer zone, the occupancy of one or more totes can be monitored at the pick-up zone on the inflow conveyor by at least one occupancy sensor, termed pick-up occupancy sensor to manage the flow of totes to the pick-up zone. Thus, the WCS can control the movement of totes to the pick-up zone in response to one or more signals from the at least pick-up occupancy sensor. Sensing the occupation of one or more totes at the pick-up zone not only improves the flow of the toted along the inflow conveyor but also provides instructions to one or more load handling devices operable on the track system to pick up a tote from the automated inventory handling station and deposit it in storage in the grid framework structure. To accommodate the one or more buffer zones, the conveyor system comprises one or more right angle transfers (RATs). The one or more right angle transfers can be between the first and / or second outflow conveyors and the inflow conveyor. The conveyors shown in Figure 13 are arranged such that the transport direction of the first, second outflow conveyors 76a, 76b and the inflow conveyor 78 are substantially parallel. One or more right angle transfers links the first and / or second outflow conveyors to the inflow conveyor. In all of the different examples of the inventory handling station shown in Figures 6 to 10, the arrangement of the conveyor system is such that the first and second decant positions are sufficiently far apart such that there is sufficient floor space at each of the first and second decant positions to separately receive inbound inventory in the form of a pallet of inbound goods without causing congestion and yet be accessible to each of the operators at their respective decant positions. This has the advantage that operators such as a robotic arm has sufficient freedom of movement to pick and deposit one or more items from a nearby pallet to a tote presented at the decant position. Various automated de-palletisers known in the art can be used to depalletize a pallet at the inbound area of the storage and retrieval system and decant the picked items into a tote presented at the decant position. The illustrative example shown in Figure 10 show two operators in the form of robotic arms 50b strategically positioned at each of the first and second decant positions 48a, 484b such that the inbound inventory on the pallet and a tote presented to the operator at each of the first and second decant positions are easily accessible by a robotic arm. The ability to space apart the first and second decant positions when presenting totes to the operators also increases the ability of the operators from adjacent decant stations to decant inbound inventory from the same pallet. In the example shown in Figures 11 and 12, operators from adjacent decant stations are able to decant from the same pallet to increase the rate by which inbound inventory can be decanted into the ASRS. In the exemplary embodiment shown in Figures 11 and 12, a plurality of the automated decant stations 142 shown in Figures 6 to 10 are arranged side-by-side such that their decant positions 48a, 48b for presenting totes to the operators are laterally disposed relative to each other. Inbound inventory arriving in one or more pallets 62 at a pallet unloading station 100 can be positioned between each of the plurality of automated decant stations 142 such that inventory on the pallets and the totes presented at each of the decant positions are easily accessible by the operators interacting with the decant station. For example, the pallet unloading station 100 and the tote presented at the decant position 48a, 48b are in easy reach by an operator manning the decant position improving the efficiency by which one or more items can be decanted into the totes. An operator at each of the decant positions are able to pick from one half of the pallet and decant them into a tote that is presented to the operator at the decant position. As inventory is typically stacked in multiple layers on a pallet, to further improve the accessibility of the items on the pallet and thereby, improve the ability to decant inventory items into the totes presented at the decant positions, the pallet can be placed on a raising platform to raise the pallet each time a layer of items has been removed from the pallet and decanted into the totes. The separation of the inventory handling positions, be it the automated decant or the pick positions, also ensures that the inventory handling station is still operational should any one of the inventory positions become non-operational. For example, one of the operators at the decant positions may not be present or one of the inflow conveyors may become non-operational for reasons of a malfunctions to one of the outflow conveyors or simply fewer inbound goods. It will be appreciated that the inventory handling station can also be an automated pick station comprising a plurality of pick positions for transferring one or more items presented at each of the plurality of pick positions into one or more delivery totes for fulfilling one or more customer orders. Thus, instead of transferring one or more inventory items between a pallet and the tote at the decant position, one or more items are transferred between the tote presented at the pick position of the automated pick station and one or more delivery totes for fulfilling one or more customer orders.

Claims

1. An automated inventory handling station for an automated storage and retrieval system,said automated inventory handling station comprising:a) a first inventory handling position and a second inventory handling position, each of the first and second inventory handling positions being configured to present one or more storage containers to an operator such that the operator is able to decant or pick one or more items into or from the one or more storage containers;b) a conveyor system arranged to receive one or more storage containers from the automated storage and retrieval system, said conveyor system comprising a first outflow conveyor and a second outflow conveyor, each of the first and second outflow conveyors comprising a drop off zone for receiving one or more storage containers from the automated storage and retrieval system, the first and second outflow conveyors being arranged to convey one or more storage containers from their respective drop off zones to the first and the second inventory handling positions respectively,c) an inflow conveyor arranged to convey one or more storage containers from the first and second inventory handling stations into the automated storage and retrieval system via a pickup zone,wherein the inflow conveyor is shared between the first and second inventory handling positions.

2. The automated inventory handling station of claim 1, wherein the automated inventory handling station is an automated decant station such that the first and second inventory handling positions are first and second decant positions respectively.

3. The automated inventory handling station of claim 1 or 2, wherein the first and second outflow conveyors are laterally disposed either side of the inflow conveyor.

4. The automated inventory handling station of claim 3, wherein the inflow conveyor is arranged to transport one or more storage containers in a direction substantially parallel to a transport direction of the first and / or second outflow conveyors.

5. The automated inventory handling station of any one of the preceding claims, wherein the inflow conveyor comprises a merge zone arranged to receive one or more storage containers from the first inventory handling station and the second inventory handling station.

6. The automated inventory handling station of any one of the preceding claims, further comprising at least one occupancy sensor for sensing the presence of at least one storage container on at least a portion of the conveyor system.

7. The automated inventory handling station of claim 6, wherein the at least one occupancy sensor comprises at least one interaction occupancy sensor for sensing the presence of one or more storage containers at the first and the second inventory handling positions.

8. The automated inventory handling station of claim 6 or claim 7 when dependent on claim 5, wherein the at least one occupancy sensor comprises at least one merge occupancy sensor for sensing the presence of one or more storage containers at the merge zone.

9. The automated inventory handling system of any one of the claims 6 to 8, wherein the conveyor system further comprises at least one buffer zone adjacent the first and / or second inventory handling positions for temporarily storing one or more storage containers.

10. The automated inventory handling station of claim 9, wherein the at least one occupancy sensor comprises at least one buffer occupancy sensor for sensing the presence of one or more storage containers at the buffer zone.

11. The automated inventory handling station of any one of the claims 6 to 10, further comprising at least one pick-up zone occupancy sensor for sensing the presence of one or more storage containers at the pick-up zone.

12. The automated inventory handling station of any one of the claims 6 to 11, further comprising a control system comprising one or more processors and memory storing instructions that when executed by the one or more processors control the conveyor system to control the flow of one or more storage containers along the at least portion of the conveyor system in response to one or more signals from the at least one occupancy sensor.

13. The automated inventory handling station of any one of the preceding claims, wherein the conveyor system is housed in an enclosure, said enclosure comprising a first opening to permit access to a storage container at the first inventory handling position and a second opening to permit access to a storage container at the second inventory handling position, said first opening being spaced apart from the second opening.

14. An automated storage and retrieval system, the automated storage and retrieval system comprising:A) an automated inventory handling station as defined in any one of the claims 1 to 13;B) a grid framework structure comprisinga track system comprising a plurality of tracks arranged in a grid pattern for guiding the movement of one or more load handling devices on the grid framework structure, anda supporting framework structure comprising a plurality of storage columns being arranged below the track system and arranged to accommodate one or more stacks of storage containers; andat least one port column through which one or more storage containers can be dropped off and picked up from the conveyor system of the automated inventory handling station.

15. The automated storage and retrieval system of claim 14, wherein the at least one port column comprises first and second drop-off columns and a pick-up column, said first and second drop off columns being arranged to drop off one or more storage containers to the drop-off zones of the first and second outflow conveyors respectively, and the pick-up column being arranged to pick up one or more storage containers from the pick-up zone.

16. The automated storage and retrieval system of claim 14 or 15, further comprising a plurality of load handling devices operable on the track system, each of the plurality of load handling devices comprising:a) a driving assembly configured to move the load handling device on the track system;b) a grabber device configured to releasably hold a storage container from above; andc) a lifting assembly through which the grabber device can drop off and pick-up storage containers from the conveyor system via the at least one port column.

17. The automated storage and retrieval system of claim 16, further comprising a warehouse control system operable to instruct one or more of the plurality of load handling devices to deliver one or more storage containers from the grid framework structure to the automated inventory handling station.

18. A method of controlling the flow of one or more storage containers between an automated storage and retrieval system and an automated inventory handling station as defined in any one of the claims 1 to 13, the method comprising the steps of:i) presenting a first storage container to a first operator at the first inventory handling station;ii) presenting a second storage container to a second operator at the second inventory handling station;iii) returning, by the conveyor system, the first storage container and / or the second storage container to the automated storage and retrieval system by determining the presence of one or more containers on the inflow conveyor.

19. The method of claim 18, further comprising the step of buffering one or more storage containers on at least a portion of the conveyor system.

20. The method of claim 19, further comprising the step of sensing the presence of one or5 more storage containers on at least a portion of the conveyor system, and in response to sensing the presence of the one or more storage containers on the at least portion of the conveyor system buffering the one or more storage containers on the at least a portion of the conveyor system.

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