Storage system and storage container

Abstract

Storage and retrieval system (fig. 3) comprising track system including first and second sets of transverse tracks to define a grid, a plurality of stacks of storage containers beneath the track syste

Description

TECHNICAL FIELD The present invention relates to the field of storage systems comprising load handling devices operative on tracks located on a grid framework structure for handling storage containers stacked in the grid framework structure, and storage containers for use in such storage systems. BACKGROUND Some commercial and industrial activities require systems that enable the storage and retrieval of a large number of different products. One known type of system for the storage and retrieval of items in multiple product lines involves arranging storage containers (also known as bins or totes) in stacks on top of one another, the stacks being arranged in rows. The storage containers are removed from the stacks and accessed from above by load handling devices, removing the need for aisles between the rows and thereby allowing a large number of containers to be stored in a given space. WO2015 / 185628A describes a storage and fulfilment system in which stacks of storage containers are arranged within a grid framework structure. The containers are accessed by load handling devices operative on tracks located on the top of the grid framework structure. The storage containers in such storage systems are typically made of a thermoplastic material and may be formed by injection moulding or blow moulding, for example. Examples of thermoplastic materials include polypropylene, polyethylene (e.g. high density polyethylene (HDPE)), acrylonitrile butadiene styrene (ABS) and polycarbonate. A problem with using thermoplastic storage containers in the storage systems described above is that they can be highly flammable and emit toxic fumes, and given that the storage system may contain hundreds or thousands of storage containers, the storage containers pose a significant risk in the event of a fire. Moreover, due to the intrinsic nature of plastic material to melt and run when set alight, there is also the risk that the fire can spread to adjacent stacks of containers. SUMMARY OF THE INVENTION The present applicant has realised that one of the main reasons for the spread of fire in a storage and retrieval system comprising a plurality of stacks of storage containers, which largely comprise of a plastic material, is the heat and / or fire from one or more storage containers in one or more stacks of storage containers spreading to storage containers in one or more adjacent stacks of storage containers. The present invention has mitigated this above problem by forming the storage container with a non-combustible enclosure that acts like a fire resistant barrier to prevent the spread of fire to one or more storage containers in one or more adjacent storage containers. For the purpose of the present invention, the term “non-combustible” is a mean that does not bum or catches fire when exposed to fire or intense heat. The non-combustible enclosure provides a fire resistant barrier to reduce or even prevent the contents of the storage container from catching fire. The present invention provides a storage and retrieval system comprising: a) a track system comprising a first set of parallel rails or tracks and a second set of parallel rails or tracks running transversely to the first set of parallel tracks in a substantially horizontal plane to form a grid pattern comprising a plurality of grid spaces or grid cells, b) a plurality of stacks of storage containers located beneath the track system, each storage container of the plurality of stacks of storage containers comprises a container bottom wall and upwardly standing opposing sidewalls and end walls arranged in a box-like structure with an open end for receiving one or more items within the box-like structure, and wherein each stack of the plurality of stacks of storage containers occupies a single grid space or grid cell, characterised in that one or more of the plurality of stacks of storage containers comprises a fire resistant container body forming a non-combustible enclosure and at least a portion of the interior surface of the fire resistant body comprises a liner formed from a food grade material. There are various non-combustible materials that can be used to form the fire resistant container body according to the present invention. These include but not limited to ceramic, metal or even plastic materials comprising a flame resistant additive such as magnesium hydroxide. Preferably, the fire resistant body is a metal container body. In comparison to plastic material, the use of metal in forming the fire resistant body of the storage containers allows the storage containers to withstand much higher temperatures before disintegrating and emit very little or no toxic fumes in an event of a fire. In addition, more of the material of the storage containers is easily recyclable, making the storage containers of the present invention to be more environmentally friendly. The use of metal in forming the fire resistant body of the storage containers also provides a sturdy structure that allows the storage containers to be stacked one above the other in a storage and retrieval system. Where the contents of the storage containers are grocery items, the storage containers are subject to strict food safety requirements to prevent chemical components of the storage container migrating into the grocery items and contaminating the grocery items. Another advantage of providing a non-combustible enclosure is that that the fire resistant container body can be formed from any type of non-combustible material, e.g. low grade steel such as galvanised steel, and is not limited to being formed from special food grade material. Typically, the metal used in the fabrication of storage containers for storing grocery items is stainless steel (e.g. 304 grade stainless steel), since stainless steel is resistant to oxidization and corrosion. However, stainless steel is relatively expensive and has a higher density than other lower grade steels. As a result, when fabricating a storage container from stainless steel for use in a storage and retrieval system comprising a plurality of stacks of containers, the walls of the storage containers would be relatively thin in comparison to a plastic storage container for an equivalent weight of storage container. Considering that multiple storage containers are stacked one top of each other which can be as high as twenty one storage containers high, the lower storage containers in a stack would have to support the weight of multiple storage containers on top. As each storage container can weigh up to 35kg, the lower storage containers in a stack would have to bear significant forces which has the potential of crushing the lower storage containers if the walls of the storage containers are not sufficiently load bearing. The use of lower grade metals having a relatively lower density than stainless steel, e.g. aluminium or lower grade steels, suffer from the problem that the metal would not comply with food safety standards. By fabricating the storage container with a fire resistant container body forming a non-combustible enclosure and a liner comprising a food grade material allows alternative lower grade or lower density but non-combustible materials to be used for the fire resistant body of the storage container. These include but not limited to galvanise steels, aluminium etc. As a result, the walls of the storage container can be made thicker and therefore, is load bearing to be used for storage of product items in a storage and retrieval system. The non-combustible enclosure of the storage container allows any type of food grade material to be used for the liner of the storage container and is not restricted to being non-combustible. Optionally, the liner comprises a food grade plastic material and / or cellulose material. To make the cellulose material resistant to moisture and / or oils, optionally, the cellulose is coated or impregnated with wax. Optionally, the cellulose material is paper or cardboard. One way of providing a paper or cardboard liner is forming the liner from a folded paper or cardboard blank. As the liner comprises paper or cardboard, optionally, the liner is disposable. One way of providing at least a portion of the interior surface of the box-like structure of the storage container with a liner is the liner is a shallow base or tray. Alternatively, the liner can extend throughout the interior surface of the box-like structure. To prevent leakage of juices from food items from a storage container contaminating food items in a storage container below in a stack, preferably, the liner is leak proof container. Optionally, the leak proof container is a one piece thermoformed container, e.g. by a blow moulding or a deep drawn moulding process. Making the storage containers fire resistant and easily transportable at lower costs represents a challenge in the industry. The present invention has mitigated this problem by providing a metallic container body that has a collapsed state for storage or transport of the plurality of storage containers and an erect state for being stacked in the grid framework structure, the collapsed state of the plurality of storage containers occupying a smaller volume than in an erect state of the plurality of storage containers. For the purpose of the present invention, the term “collapsed start” represents a condition where at least a portion of the metallic container body is collapsible in the sense that when a plurality of storage containers are stack, they occupy a smaller volume than when they are in an erect state. There are numerous ways to fabricate a metallic container body to be collapsible. These include but is not limited to at least a portion of metallic container body can be flat packed, stacked, disassembled and / or separated but does not include the metallic container body being crushed. Optionally, at least one of upwardly standing opposing sidewalls and / or end walls are separable so that at least a portion of the metallic container body is collapsible. Separation of the upwardly standing opposing sidewalls and / or end walls include but is not limited to at least one edge or end of the upwardly standing opposing sidewalls and end walls being physically separated from each other. This optionally includes the upwardly standing opposing sidewalls and / or end walls being physically separated from the container bottom wall. The separable nature of the upwardly standing opposing sidewalls and / or end walls also enables different parts of the storage container to be replaceable should any one of the walls are damaged. Optionally, at least a portion of the metallic container body is formed from a deep drawn sheet metal blank in which a sheet metal blank is drawn into a forming die by the mechanical action of a punch. Brief Description of Drawings Further features and aspects of the present invention will be apparent from the following detailed description of an illustrative embodiment made with reference to the drawings, in which: Figure 1 is an illustration of an automated storage and retrieval system according to an exemplary embodiment of the present invention. 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 container receiving space within the body of the load handling device. 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 schematic perspective view of the grabber device positioned above the storage container. Figure 7(a) is a schematic perspective view of the grabber device mounted on the storage container. Figure 7(b) is a schematic perspective view of the grabber device engaging with the storage container. Figure 8 is a schematic perspective view of a storage container formed by a deep drawn process according to a first embodiment of the present invention. Figure 9 is a schematic perspective view of a storage container formed by a deep drawn process according to a second embodiment of the present invention. Figure 10 is a schematic perspective of a storage container formed by a deep drawn process and showing (a) an exploded view of the assembly components of the storage container; and (b) assembled storage container according to a third embodiment of the present invention. Figure 11 is a schematic perspective of a storage container partially formed by a deep drawn process and showing (a) an exploded view of the assembly components of the storage container; and (b) assembled storage container according to a fourth embodiment of the present invention. Figure 12 is a schematic view of a storage container partially formed by a deep drawn process according to a fifth embodiment of the present invention. Figure 13 is a schematic perspective view of a storage container partially formed by a deep drawn process and showing (a) a pre-assembled view of the storage container; and (b) the assembled storage container according to a sixth embodiment of the present invention. Figure 14 is a schematic perspective view of a storage container partially formed by a deep drawn process and showing (a) a pre-assembled view of the storage container; and (b) the assembled storage container according to a seventh embodiment of the present invention. Figure 14(c) is a schematic perspective view of an assembled storage container showing the connection of the upper wall parts by a releasable toggle latch. Figure 14(d) is a perspective view of the releasable toggle latch for connecting the upper wall parts together of the metallic container body shown in Figure 14(c). Figure 14(e) is a perspective view of the separate parts of the metallic container body shown in Figure 14(b) and Figure 14(b) in a stack. Figure 15 is a schematic perspective of a storage container partially formed by a deep drawn process and showing (a) a pre-assembled view of the storage container; and (b) the assembled storage container according to an eighth embodiment of the present invention. Figure 16 is a schematic perspective of a storage container partially formed by a deep drawn process and showing (a) a pre-assembled view of the storage container; and (b) the assembled storage container according to an ninth embodiment of the present invention. Figure 17 is a schematic view of a stack of the pre-assembled storage container of Figure 15 or Figure 16. Figure 18 is a schematic perspective view of (a) the blanks of foldable metal sheet; and (b) erected metallic container body from the blanks according to a tenth embodiment of the present invention. Figure 19 is a schematic perspective view of (a) a unitary blank of foldable metal sheet; and (b) erected metallic container body from the unitary blank according to an eleventh embodiment of the present invention. Figure 20 is a schematic perspective of a cast storage container according to a twelfth embodiment of the present invention. Figure 21 is a schematic perspective of a storage container comprising hollow walls according to a thirteenth embodiment of the present invention. Figure 22 is a schematic view of a storage container comprising a fire resistant body forming a non-combustible enclosure and a partial liner. Figure 23 is a schematic view of the partial liner of the fire resistant body shown in Figure 22. Figure 24 is a schematic view of a storage container comprising a fire resistant body forming a non-combustible enclosure and a full height liner. Figure 25 is a schematic view of the full height liner of the fire resistant body shown in Figure 24. DETAILED DESCRIPTION As shown in Figures 1 and 2, storage containers 10, also known as bins or totes, 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 is made up of a plurality of storage columns or grid columns. Each grid in the grid framework structure has at least one grid 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 containers 10 arranged within the framework structure 14. Each container 10 typically holds a plurality of product items (not shown), and the product items within a container 10 may be identical, or may be of different product types depending on the application. Each container 10 may be used to store grocery items (i.e. food items), for example. 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 containers 10 are stacked between the members 16, 18,20 ofthe grid framework structure 14, so that the grid framework structure 14 guards against horizontal movement of the stacks 12 of containers 10, and guides vertical movement of the containers 10. The top level of the grid framework structure 14 includes 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. As shown in Figures 1 and 2, stackable storage containers, known as bins 10, are stacked on top of one another to form stacks 12. The stacks 12 are arranged in a grid frame structure 14 in a warehousing or manufacturing environment. Figure 1 is a schematic perspective view of the grid frame structure 14, and Figure 2 is a top-down view showing a single stack 12 of bins 10 arranged within the grid frame structure 14. Each bin 10 typically holds a plurality of product or inventory items 28, and the inventory items within a bin 10 may be identical, or may be of different product types depending on the application. Furthermore, the bins 10 may be physically subdivided to accommodate a plurality of different inventory items. In the description below, bins 10 will be used to denote the storage containers intended for the storage of inventory items, whilst delivery containers DT will be used to denote containers fdled or intended to be fdled to fulfd customer orders placed by customers. It will be appreciated that this terminology is used for ease of reference and explanation within this document. However, it should be noted that the bins 10 and the containers DT may be of the same shape and configuration. Furthermore, delivery containers DT may be stored in bins 10 within the storage system or any part thereof. The gridframe structure 14 comprises a plurality of upright members 16 that support horizontal grid 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. The bins 10 are stacked between the upright members 16 of the frame structure 14, so that the frame structure 14 guards against horizontal movement of the stacks 12 of bins 10, and guides vertical movement of the bins 10. The top level of the grid frame structure 14 includes tracks or rails 22 arranged in a grid pattern across the top of the stacks 12 to form a track system. Referring additionally to Figure 3, the tracks or rails 22 support a plurality of robotic load handling devices 30. A first set 22a of parallel tracks or rails 22 guide movement of the load handling devices 30 in a first direction (X) across the top of the frame structure 14, and a second set 22b of parallel tracks or rails 22, arranged perpendicular to the first set 22a, guide movement of the load handling devices 30 in a second direction (Y). In this way, the track system 22 allow movement of the load handling devices 30 in two dimensions in the X-Y plane, so that a load handling device 30 can be moved into position above any of the stacks 12. Each load handling device 30 comprises a vehicle 32 which is arranged to travel in the X and Y directions on the tracks or rails 22 of the grid frame structure 14, above the stacks 12 (see Figure 4). Figures 4 and 5 shows a load handling device 30 according to an embodiment of the present invention and described in International patent application WO 2015 / 140216 (Ocado Innovation Limited), the contents of which are incorporated herein by reference. The load handling device 30 comprises a vehicle body 32 equipped with a lifting mechanism 33 (see Figure 4) comprising a winch or a crane mechanism 35 to lift a storage container or bin 10, also known as a tote, from above. The crane mechanism 35 comprises a winch cable 38 wound on a spool or reel and a grabber device 39. Typically, the lifting device comprises a set of lifting tethers 38 extending in a vertical direction and connected nearby or at the four comers of the grabber device 39 (one tether near each of the four comers of the grabber device) for releasable connection to a storage container 10. The grabber device 39 is configured to grip the top of the storage container 10 and lift it from a stack of containers in a storage system of the type shown in Figures 1 and 2. Typically, the grabber device 39 is configured as a lifting frame. Further details of the grabber device is discussed below. The vehicle body 32 comprises an upper part and a lower part (see Figure 5(a and b)). The lower part is fitted with two sets of wheels 34, 36, which mn on rails at the top of the framework structure of the storage system. The upper part of the vehicle body 32 may house a majority of the bulky components of the load handling device. Typically, the upper part of the vehicle body houses a driving mechanism 42 for driving both the wheels and the lifting mechanism together with an on-board rechargeable power source for providing the power to the driving mechanism and the lifting mechanism. The lower part of the vehicle body 32 comprises a wheel assembly that is are driven to enable movement of the vehicle in X and Y directions respectively along the rails. A first set of wheels 34, consisting of a pair of wheels 34 on the front of the vehicle 32 and a pair of wheels 34 on the back of the vehicle 32, are arranged to engage with two adjacent rails of the first set 22a of rails 22. Similarly, a second set of wheels 36, consisting of a pair of wheels 36 on each side of the vehicle 32, are arranged to engage with two adjacent rails of the second set 22b of rails 22. 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. When the first set of wheels 34 is engaged with the first set of tracks or rails 22a and the second set of wheels 36 are lifted clear from the tracks or rails 22, the wheels 34 can be driven, by way of a drive mechanism (not shown) housed in the vehicle 32, to move the load handling device 30 in the X direction. To move the load handling device 30 in the Y direction, the first set of wheels 34 are lifted clear of the tracks or rails 22, and the second set of wheels 36 are lowered into engagement with the second set of tracks or rails 22a. The drive mechanism can then be used to drive the second set of wheels 36 to achieve movement in the Y direction. 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 on the track system. The wheels are arranged around the periphery of a cavity or recess, known as a containerreceiving recess 40, in the lower part. The recess 40 is sized to accommodate the storage container or bin 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 load handling device can move laterally to a different location. On reaching the target location, for example another stack, an access point in the storage system or a conveyor belt, the bin or storage container can be lowered from the container receiving space and released from the grabber device 39. In this way, one or more robotic load handling devices 30 can move around the top surface of the stacks 12 on the frame structure 14, as shown in Figure 3 under the control of a centralised control utility (not shown). Each robotic load handling device 30 is provided with a lifting mechanism 38 for lifting one or more bins 10 from the stack 12 to access the required items stored therein. The body of the vehicle 32 can comprise the container receiving space in the form of a cavity 40 for accommodating a bin 10 (see Figure 5a). The cavity 40 being of a size capable of holding a bin or storage container 10. The lifting mechanism comprising a set of lifting tethers extending in a vertical direction are connected at the four comers of a lifting frame (not shown), otherwise known as the grabber device (one tether near each of the four comers of the grabber device) for releasable connection to a storage container. The grabber device is configured to releasably grip the top of a storage container to lift it from a stack of containers in a storage system of the type shown in Figure 1 and 3. The lifting mechanism lifts a bin 10 from the stack 12 to within the cavity 40 within the body of the vehicle 32. Whilst the container receiving space 40 for accommodating a bin 10 when it is lifted by the winch means is arranged within the vehicle body 32 shown in Figure 4, the present invention is not limited to the container receive space 40 being located within the vehicle body 32. The present invention is also applicable to the container receiving space being located below a cantilever such as in the case where the vehicle body of the load handling device has a cantilever constmction as described in WO2019 / 238702 (Autostore Technology AS). For the purpose of the invention, the term ‘vehicle body” is constmed to optionally cover a cantilever such that the grabber device is located below the cantilever. However, for ease of explanation of the present invention, the container receiving space for receiving a container is arranged within a cavity or recess within the vehicle body. The container receiving space allows multiple products can be accessed from multiple locations in the grid and stacks at any one time. The robotic load handling devices 30 remove bins 10 containing inventory items 28 (not shown) therein and transport the bins 10 to picking stations (not shown) where the required inventory items 28 are removed from the bins 10 and placed into bins 10 comprising delivery containers DT. It is important to note that a delivery container DT may fit within a bin 10. The bins 10 may comprise inventory items 28 or may comprise delivery containers DT. Furthermore, the delivery containers DT may comprise at least one bag 52, the inventory items 28 being picked directly in to a bag 52 at a pick station (not shown). The empty bins 10 or the bins comprising delivery containers DT or the bins comprising delivery containers DT and bags 52 may all be stored within the stacks 12. It will be appreciated that all the bins 10 have substantially the same external shape and configuration. Figure 3 shows a typical storage and retrieval system as described above, the system having a plurality of load handling devices 30 active on the grid above the stacks 12. Figures 1 and 3 show the bins 10 in stacks 12 within the storage system. It will be appreciated that there may be a large number of storage containers or bins 10 in any given storage system and that many different items 28 may be stored in the bins 10 in the stacks 12, each bin 10 may contain different categories of inventory items 28 within a single stack 12. In one storage and retrieval system described above and further in UK Patent Application Number GB1410441.8 - Ocado Innovation Limited, hereby incorporated by reference, the storage and retrieval system comprises a series of bins 10 that may further comprise delivery containers DT with customer orders contained therein or may further comprise bins 10 with inventory items 28 awaiting picking contained therein. These different bins 10 and combinations thereof may be contained in the storage system and be accessed by the robotic load handling devices 30 as described above. Figure 6 show a grabber device positioned above one form of bin 10 for use within the storage and retrieval system of Figures 1 to 3. The storage container orbin 10 comprises a substantially box type structure having an open top 43, a container bottom wall 44, and opposing sidewalls 46 (a and b) and end walls 48 (a and b). In the particular example shown in Figure 6, the bin 10 has a substantially rectangular shaped container bottom wall 44 such that the length of the opposing sidewalls 46 (a and b) are longer than the length of the opposing end walls 48 (a and b). The opposing sidewalls 46 (a and b) and end walls 48 (a and b) of the bin comprises one or more ribs to reinforce the sidewalls and end walls of the storage container. A plurality of the bins 10 may be stacked in a self-supporting stack 12, a plurality of stacks 12 being disposed within the grid framework structure 14 as described above. In storage facilities of the type described with reference to Figures 1 to 3, it will be appreciated that there may be a large number of bins 10, in some cases hundreds of thousands. Typically, each bin 10 must be able to bear the load of multiple bins 10 in a stack. The bin stack load is carried by the maximum load of twenty fully loaded bins. The weight of a fully loaded bin is about 35kg, of which 5kg represents the weight of the bin alone. For example, a stack of twenty bins 10 would represent a load of 700kg or 6,867N. The one or more ribs on the opposing sidewalls and end walls strengthens the sidewalls and end walls so as to prevent sidewalls and end walls buckling under such a load in a stack. To allow air to flow within the bins 10 when held in a stack, the sidewalls 46 (a and b) and / or end walls 48 (a and b) of the bins 10 comprise one or more slots or openings or vent holes 50. The slots or openings 50 in the sidewalls 46 (a and b) and / or end walls 48 (a and b) allow air circulating within and around the storage and retrieval system to flow within the bins 10. This is particularly important in the case where the bins 10 are located in a chilled zone of the storage and retrieval system where cool air from a refrigerated or air conditioning unit is circulated around at least a portion of the grid framework structure for keeping items such as grocery items at a chilled temperature. Cooling systems such as that described in UK Patent Application No GB1509661.3 (Ocado Innovation Limited) require air to flow within the storage system and through the bins 10 and stacks 12 of bins 10. The system described in this UK Patent Application is hereby incorporated by reference and discloses a storage system comprising one or more heater and / or one or more chiller for generating temperature controlled gas, one or more fans for circulating the temperature controlled gas through the storage system; and a plenum for receiving the temperature controlled gas. Should a portion of the storage and retrieval system require cooling to a lower temperature, for example to enable storage of items requiring chilling, such as fruit and vegetables, it is more important that the air flow through the system cools the items to be stored. Whilst the embodiments herein are described with reference to cooling the storage system, it will be appreciated that, using the same method described, the items stored in the storage system may be heated in a similar manner. Furthermore, whilst the description above refers to air flow, it will be appreciated that any suitable gas may be circulated to heat or cool the system as required. In addition to allowing air to circulate within the bins, the slots 50 in the bins 10 enable the same amount of storage volume to be utilised, whilst maintaining the structural integrity of the bin 10 yet reducing the weight of the bin 10. Advantageously, providing apertures 50 in the containers DT or bins 10 also reduces the cost of each container DT or bin. In a storage and retrieval system 1 comprising hundreds of thousands of containers and bins this can represent a significant saving. In the drawing of the bin 10 shown in Figure 6, two sides of the container or bin comprise openings or holes 50. One or more handles 52 are integrally formed into the end walls 48 (a and b) of the bin 10 to enable the storage container to be manually picked up by an operative. The openings or vent holes 50 in the sidewalls 46 (a and b) and / or end walls 48 (a and b) are located at a predetermined height above the bottom wall 44 of the storage container 10 so as to provide a leak proof base, and thereby prevent escape of fluid that has accidently escaped from the contents of the storage container contaminating the contents of adjacent storage containers in a stack. Also shown in Figure 6 is the grabber device 39, which forms part of the lifting mechanism 33 of the robotic load handling device, positioned above the bin 10. The lifting mechanism 33 used to lift the containers into the container receiving space can take any suitable form and comprises a winch or a crane mechanism (see Figure 4). The crane mechanism comprises a winch cable 38 wound on a spool or reel and a grabber device 39. The grabber device 39 is configured to grip the top of the container 10 to lift it from a stack of containers in a storage system of the type shown in Figures 1 and 2. Typically, the grabber device 39 is configured as a frame 54 and four lifting tethers 38 are fixed to each comer of the grabber device 39 (see Figure 5b). For maximum stability and load capacity, commonly four lifting tethers 38 are used to winch the grabber device 39, with one tether disposed nearby or at each of the comers of the grabber device 39, but a different arrangement, for example with fewer tethers, could be used if desired. One end, e.g. first end, of each of the tethers is wound on the spool in the load handling device and the other end, e.g. second end, is fixed to the grabber device 39, typically at each comer of the grabber device, by a suitable bracket (not shown). The number of tethers attached to the grabber device is dependent on the ability to maintain the grabber device horizontal during operation when picking up a container 10 and the ability to withstand the tension applied to the tethers when lifting containers, which could weigh up to 40kg, without extending or stretching, i.e. be inextensible under a predetermined applied tensile stress. To possess the necessary physically properties (Young’s Modulus), the tethers are generally in the form of a tape, but other tethers with the necessary physical properties to winch containers are permissible to winch the bin from a stack. In the particular embodiment shown in Figure 6, the frame 54 of the grabber device has four comer sections 56, a top side and a bottom side. To grab a container 10, the grabber device 39 comprises four locating pins or guide pins 58 nearby or at each comer of the grabber device 39 which mate with corresponding cut outs or holes 60 formed at four comers of the container 10 and four gripper elements 62 arranged at the bottom side of the grabber device 39 to engage with the rim 64 of the bin 10 (see Figure 7a). The locating pins 58 help to properly align the gripper elements 62 with corresponding holes 60 in the rim 64 of the container. In the particular embodiment shown in Figure 7a, each of the gripper elements 62 comprises a pair of wings 66 that are collapsible to be receivable in corresponding holes 60 in the rim 64 of the container and an open enlarged configuration having a size greater than the holes 62 in the rim 64 of the container 10 in at least one dimension so as to lock onto the container 10 (see Figure 7b). The wings are driven into the open configuration by a drive gear (not shown). More specifically, the head of at least one of the wings comprises a plurality of teeth that mesh with the drive gear such that when the gripper elements 62 are actuated, rotation of the drive gear causes the pair of wings to rotate from a collapsed configuration (Figure 7a) to an open enlarged configuration (Figure 7b). When in the collapsed or closed configuration, the gripper elements 62 are sized to be receivable in corresponding holes 60 in the rim 64 of the container 10 as shown in Figure 7a. The foot of each of the pair of wings comprises a stop 68 (see Figure 6), e.g. a boss, such that when received in a corresponding hole 60 in the rim 64 of the container 10, the stop 68 engages with an underside of the rim 64 when in an enlarged open configuration to lock onto the container when the grabber device 39 is winched upwards towards the container-receiving space of the load handling device. Figure 7b shows the configuration of the gripper elements in an enlarged configuration for lifting the bin 10 into the container receiving space of the robotic load handling device. The gripper elements 64 are received in the holes 60 in the rim 64 of the container 10 when the grabber device 39 is at a predetermined height above the rim of the container as measured by one or more depth sensors (not shown) mounted to the underside of the grabber device. At this depth, the gripper elements 64 are actuated to grab the bin 10 in response from a signal from the one or more of the depth sensors (not shown) mounted to the underside of the grabber device 39. Typically, the bins 10 are largely composed of a thermoplastic material and are either injected moulded or blow moulded. Known thermoplastic material commonly used in the moulding of the storage containers comprises a polyolefin, e.g. polypropylene or polyethylene, (e.g. high density polyethylene (HDPE)), acrylonitrile butadiene styrene (ABS) and polycarbonate including copolymers thereof. However, the problem with such plastic materials is that they are flammable and emit toxic fumes. Once a fire has started within the storage and retrieval system, the flammable and exothermic nature of the material of the bins 10 would result in the fire spreading throughout the storage and retrieval system with a danger to life. Not only are the bins 10 flammable but the combustion fumes emitted from the burning thermoplastic material are highly toxic comprising benzene, which is a known carcinogen. Inhalation of fine particles as a result of the burning debris may cause respiratory irritation. As a result, extreme fire precaution methods and systems are incorporated into the storage and retrieval system to prevent the rapid spread of fire, such as sprinklers and srnoke / heat detection units. Whilst efforts have been made to prevent the rapid spread of fire, of which the bins 10, play a major role in the spread of the fire, there is still the problem of fire spreading throughout the storage and retrieval system. The present invention has mitigated the above problem by providing a storage container comprising a metallic container body comprising a container bottom wall and opposing side walls and opposing end walls. In the examples of the different types of storage containers discussed below with reference to Figures 9 to 19, the entirety of the storage container is formed from the metallic container body in the sense that the metallic container body is the storage container. However, the storage container of the present invention is not limited to being entirely formed from a metallic container body and at least a portion of the storage container can comprise other materials, e.g. plastic material. For example, the metallic container body can form a metallic lining of the storage container. The storage container comprising the metallic container body is also applicable to delivery containers, DT, in the sense that the delivery container can also comprise a metallic container body of the present invention comprising a container bottom wall and opposing sidewalls and opposing end walls. The storage containers described below with reference to Figure 9 to 19 relate to the storage container being formed from a metallic container body. For ease of explanation, the metallic container body in the forthcoming examples can be referred to as storage containers. The metallic container body of the present invention can have a similar shape to the storage containers currently in existence for storing items in the grid framework structure, e.g. having a substantially rectangular container bottom wall and opposing side walls and end walls. The metallic storage containers can be used amongst the traditional plastic storage containers in the storage and retrieval systems described above with reference to Figure 3. The flame resistant behaviour of the metallic storage containers can be used to form a flame resistant barrier wall in the grid framework structure. For example, a plurality of stacks of metallic storage containers can be arranged to form one or more flame resistant barrier walls surrounding the plurality of stacks of plastic storage containers. One or more flame resistant barrier walls comprising the metallic storage containers can be used to contain any flames wdthin the grid framework structure. There are numerous methods to fabricate the storage containers comprising the metallic container body according to the present invention. For use in an automated storage and retrieval system, the key features of the storage containers is lightness having a weight below 8kg, preferably below 6kg, more preferably below 5kg. The storage container comprising the metallic container body should also have sufficient structural rigidity to withstand loads being applied to them when placed in a stack. The grid framework structure can hold stacks of storage containers as much as twenty storage containers high. Considering that each of the storage containers can weigh up to 35kg, this amounts to a weight of 700kg. Below are the different examples according to the present invention of the different storage containers comprising a metallic body according to the present invention. Where the storage container comprising the metallic container body is used for storage of grocery items, it is important that the storage container is leak proof to prevent leakage of food items escaping the storage container and contaminating other food items stored in adjacent storage containers in a stack. Since fluid tends to settle at the base of the storage container, the base of the metallic container body is made leak proof and any vent holes in the sidewalls and / or end walls of the metallic container body are located a predetermined height above the container bottom wall to prevent escape of fluid through the vent holes. Figure 8 is an example of a storage container 110 comprising the metallic container body 112 according to a first embodiment of the present invention where the storage container 110 is formed from a deep drawn presswork of a sheet metal blank comprising a container bottom wall 115 and opposing sidewalls 116 (a and b) and opposing end walls 118 (a and b). A sheet metal blank is mechanically drawn into a forming die which resembles the shape of the storage container by the mechanical action of a punch. The advantage of the deep drawn process over other metal forming process is the ability to create a leak proof storage container. The storage container 110 can be fabricated from stainless steel sheet metal having a thickness in the range 0.5mm to 2.0mm. However, other metals can be used in the fabrication of the metallic container body including but not limited to aluminium. To provide the necessary structural rigidity of tire walls of the storage container, preferably the thickness of the sheet metal blank is about 2mm. The storage container 110 shown in Figure 8 is an example where the storage container is formed from a full deep drawn using a single or unitary sheet metal blank. Like the storage container discussed above, the opposing sidewalls 116 (a and b) and end walls 118 (a and b) of the storage container 110 comprise one or more slots or openings or ventholes 120 to permit the flow of air within the storage container 110. Ure one or more slots 120 can be cut into the sheet metal blank prior to the deep drawn process, or alternatively the one or more slots can be cut out or stamped into tire opposing sidewalls and / or end walls of tire storage container after the deep drawn process. Similarly, one or more ribs 122 can be stamped into the sidewalls 116 (a and b) and end walls 118 (a and b) of the storage container 110 to reinforce the walls of the storage container, and thereby improve the structural integrity or sturdiness of the formed storage container. Similarly to the storage container in the art, one or more handles 124 are formed in the sidewalls and / or end walls of the storage container. To enable the grabber device of the lifting mechanism to engage with the rim of the storage container and lift the storage container into the container receiving space of the robotic load handling device, at least a portion of the rim is formed with a lip or flange 126 to enable a grabber device to engage with the rim. To create the lip or flange 126, the upper edges of the opposing sidewalls and / or opposing end walls are turned or bent inwardly and / or outwardly. In the particular example of the first embodiment of the present invention, the rim at the upper edge of the opposing end ■walls of the metallic container body are outwardly turned to form a flange or lip 126 for the grabber device, in particular the gripper elements to engage with the rim of the storage container. The lip or flange 126 can have one or more openings (not shown) to receive a gripper element within the one or more openings. To enable the storage containers of the first embodiment of the present invention to be stacked one on top of the other in the storage and retrieval system, the storage container comprises one or more stops 128 at the corners of the storage container 110. The container bottom wall of an adjacent storage container above in a stack butts up or is supported by the one or more stops of a storage container below, and thereby prevents the container bottom wall of the adjacent storage container from fouling or crushing the contents of the storage container below in a stack. In the particular embodiment of the present invention shown in Figure 8, the stops 128 are formed. by one or more indentations that extend inwardly from the comers into the interior space of the metallic container body 112. To provide further structural support to the deep drawn storage container in the first embodiment of the present invention shown in Figure 8 for bearing a load when placed in a stack, one or more comer posts 230 can be mounted either externally or internally at the comers of the storage container 220. In a second exemplary embodiment of the present invention shown in Figure 9, a comer post 230 is mounted externally at each of the comers of the storage container 220. Each of the comer posts 230 at the comers of the storage container extend along the foil height or depth of the storage container 220 such that the corner posts 230 bear the full weight of an adjacent storage container above in a stack and the metallic container body 212 simply provides the function of containment of items within the storage container. In other words, the corners posts 230 provide a resting surface for adjacent storage containers in a stack. To provide the necessary' structural rigidity, the comer posts are cast from metal, preferably die cast. Considering that the thickness of the comers posts is greater than the walls of the metallic container body, which is fabricated from a sheet metal blank, other lightweight materials can be used in the fabrication of the corner posts such as plastic material. As a result, the material of the storage container can be a combination of metal forming the metallic container body and the plastic comer posts at the comers of the metallic container body. Tire use of plastic comer posts help to keep the overall weight of the storage container low, e.g. less than 6kg, preferably less than 5kg. In a third exemplary embodiment of the present invention shown in Figure 10 (a and b), one or more of the opposing sidewalls 316 (a and b) and / or opposing end walls 318 (a and b) of the deep drawn metallic container body 312 of the storage container 310 can be reinforced by one or more inserts or wall stiffeners 332. As shown in Figure 10, the wall inserts 332 are placed against each of the opposing end walls 316 (a and b) of the metallic container body 312 and extend from the container bottom wall 315 to the rim 334 at the upper edge of the metallic container body 312. To provide a support surface to facilitate stacking of adjacent storage containers in a stack, the upper edge of the wsdl insert 332 is outwardly turned to form a lip 326 at the rim of the metallic container body, lire outwardly turned lip 326 comprises one or more openings 336 to enable a grabber device to engage with the rim of the metallic container body and lift the storage container from its stack. Ure wall stiffeners or inserts 332 can be cast into plates, preferably die cast to provide the necessary structural integrity to the walls of the storage container 310 to bear the weight of adjacent storage container in a stack. Whilst metal, e.g, steel or aluminium, is preferably used to cast the wall stiffeners 332, other structural integral materials such as plastic can be used to fabricate the wall stiffeners. The wall stiffeners 332 can optionally comprise one or more recesses 338 m close proximity to the rim or mouth of the storage container 310 to facilitate stacking of the storage containers, i.e. the one or more recesses 338 in the wall stiffeners provide one or more stops that are configured to provide a support surface that cooperates with the container bottom wall of an adjacent storage container above in a stack. The lower edge of the wall stiffener 332 can either butt up against the container bottom wall 315 of the metallic container body 312 or comprise one or more tabs 340 that are received in slots in the bottom container wall 315. The walls namely the opposing sidewalls 316(a and b) and the opposing end walls 318(a and b) of the metallic container body 312 are outwardly inclined from the container bottom wall 315 such that the metallic container body 312 is tapered. Tire tapered body pennits the metallic container body to fit inside another metallic container body such that a plurality of storage containers can be stacked neatly within each other and thereby, occupy less storage space. In use, the walls stiffeners 338 can be inserted against the one or more of the sidewalls 316(a and b) and / or end walls 318(a and b) of the metallic container body 312 so as to enable one or more storage containers to be supported on top of each other. In transit, the wall stiffeners 338 can be stored separately so as to allow a plurality of tire metallic container bodies 312 to be neatly stacked together. The metallic container body of the first, second and third embodiment of the present invention is formed from a full deep drawn sheet metal blank. In other words, the entirety of the metallic container body can be deep drawn from a unitary sheet metal blank. The formed deep drawn structure can be fettled or cut to size to form the metallic container body. Examples of fettling include but are not limited to cutting and / or filing the edges of the deep drawn structure. The foil deep drawn process suffers from the problem of being a bulky product since the storage container occupies a relatively large portion of storage space when being transported. Considering that thousands of storage containers are needed in a typical storage system, transporting and storing the bulky product is costly and uneconomical. A storage container comprising a metal container body is thus required that does not represent a bulk product when being transported or stored for use. In comparison to forming the metallic body of the storage container by a full deep drawn process as discussed with reference to Figures 8 to 10 (a and b), the metallic container body as shown in Figures 11 (a and b) to 16 can be fabricated by a two stage forming process comprising a combination of a deep drawn process in combination with erecting one or more blanks comprising foldable sidewalls. In the exemplary embodiments shown in Figures 11 (a and b) to 16, the metallic container body comprises a lower portion and an upper portion. The lower portion comprises a deep drawn base comprising the container bottom wall and opposing sidewalls and end walls forming a shallow base or tray. The deep drawn process for forming the lower portion enables the lower portion of the metallic container body to be leak proof. The upper portion of the metallic container body is collapsible in the sense that the upper portion can be erected from a folded sheet metal blank or cast into plates that are pivotally connected together, lire sheet metal blank can comprise one or more fold lines to assi st with the folding of the sheet metal blank to define the sidewall and end wall of the metallic container body. Tire advantage of forming the metallic container body by a two stage forming process is that storage of the metallic container body comprising an upper and lower portion for transport makes an efficient use of storage space. For example, multiple bases can be stacked together for transport. Similarly multiple sheet metal blanks or plates can be flat packed together and then erected at the point of use. Figure 11 (a and b) is an exemplary embodiment of a metallic container body 412 formed by tiie two stage forming process according to a fourth embodiment of the present invention. Figure 11(a) shows the metallic container 410 formed from two parts, a lower part 440 and an upper part 442, and Figure 11(b) shows the separate parts 440, 442 being brought together to form the box-like structure of the metallic container body 412 according to an exemplary' embodiment of the present invention, i.e. the lower part 440 forms a lower portion and the upper part 442 forms the upper portion of the metallic container body. The lower part 440 is formed by deep drawing or stamping a sheet metal blank to form a shallow base or tray 444 comprising the container bottom wall 415 and upwardly standing opposing sidewalls 446 (a and b) and end walls 448 (a and b). The upper part 442 is formed from two separate sheet metal blanks 450 (a and b) that are folded to form the opposing sidewalls 452 (a and b) and end walls 454 (a and b) of the metallic container body 412. A first sheet metal blank 450a is folded to form one end wall 454a of the metallic container body and a portion of the pair of opposing side walls of the metallic container body. A second sheet metal blank 450b is folded to form the other end wall 454b of the metallic container body and a portion of the pair of opposing side walls of the metallic body. The opposing sidewall portions are pivotally attached to their respective end walls 454 (a and b) of the first and second sheet metal blank 450 (a and b) by a living hinge 460 or other suitable pivotable connection. Tire first and second sheet metal blanks 450 (a and b) comprise one or more fold lines to assist with the folding of the respective sheet metal blanks to form the sidewalls and end walls of the metallic container body. As a result, the first and second sheetmetal blanks are folded to form two respective C shaped folds such that when erected and assembled or brought together as shown in Figure 11(b), each of the opposing side wall portions from the respective first 450a and second 450b sheet metal blanks lie in substantially parallel vertical planes. In other words, the C shaped folds are brought together to form a tubular like structure forming the upper portion of the metallic container body. The tubular like structure is offered up to the lower shaped part 440 where it is inserted within the shallow base 444 of the lower part 440 of the metallic container body 412 to form a box-like structure with an open end or mouth as shown in Figure 11(b). When assembled together, the opposing sidewalls 416 (a and b) of the metallic container body 412 comprise an upper sidewall part and a lower sidewall part. Similarly, the opposing end walls 418 (a and b) of the metallic container body 412 comprise an upper end wall part and a lower end wall part. The opposing sidewalls 446 (a and b) and end walls 448 (a and b) of the shallow part of the metallic container body respectively form the lower sidewall parts and lower end wall parts of the metallic container body. The opposing sidewalls and end walls of the upper portion of the metallic container body 412 form the upper sidewall parts and upper end wall parts of the metallic body. The combination of the deep drawn shallow base and the C shaped folds allows at least a portion of the metallic container body to be collapsible for ease of transport. The collapsible portion of the metallic container body comprising the sheet metal blanks can also include a plurality of vent holes 462 stamped into the sheet metal blanks to assist with the circulation of fluid, e.g. air, within the interior space of the metallic container body. The thickness of the sheet metal blank for forming the lower portion and / or upper portion can be in the range 0.55mm to 1mm thick and composed of stainless steel but other metals such as aluminium can be used in the fabrication of the metallic container body. The opposing sidewalls and end walls of the lower portion can outwardly inclined from the container bottom wall 415 such that the walls 446 (a and b), 448 (a and b) of the shallow base 444 are slightly tapered. This allows multiple shallow bases or trays 444 to be conveniently stacked together as demonstrated in Figure 17. Also shown in Figure 11 (a and b) is one or more stops 464 at the comers of the metallic container body 412 that are spaced apart and configured to allow vertically adjacent storage containers to be stacked one on top of the other. The stops 464 at the comers are spaced apart above the container bottom wall 415 so as to prevent the container bottom wall of an adjacent storage container above in a stack from crushing the contents of the storage container below. In the particular embodiment shown in Figure 11 (a and b), the one or more stops 464 are formed by stamping depressions at the comers of the metallic container body, but other means to form the stops are applicable in the present invention. The top edge of at least one of the opposing walls at the rim of the metallic container body is outwardly turned to form a lip or flange 466 for a grabber device of a load handling device to releasably engage and pick the storage container comprising the metallic container body from a stack. Instead of the upper portion of the metallic container body being supported by the shallow base of the lower portion by inserting the C-shaped folds into the shallow base as shown in Figure 1 l(a and b), in a fifth exemplary embodiment 510 of the present invention shown in Figure 12, the upper sidewall parts 570 (a and b) and end wall 572 (a and b) parts can be fixedly connected to the respective lower sidewall parts 546 (a and b) and end wall parts 548(a and b) of the shallow base to form a box like structure, e.g. by riveting or welding. Equally, the ends of the C-shaped folds are fixedly connected together to form the upper portion of the metallic container body, which in turn is fixedly connected to the lower portion of the metallic container body 512. An alternative to the embodiment of the metallic container body shown in Figures 1 l(a and b) and 12, is the embodiment 610 shown in Figure 13 (a and b) where the sidewalls 670 (a and b) and end walls 672 (a and b) in the upper portion of the metallic container body 612 are held together by one or more retainers 674, 676. As with the other embodiments shown in Figure 11 (a and b) and 12, the upper portion of the metallic container body is collapsible in the sense that the upper portion is erected from a folded sheet metal blank. Two sheet metal blanks 650 (a and b) are shown wherein each of the two sheet metal blanks 650 (a and b) is foldable to define the sidewall 670 (a and b) and end wall 672 (a and b) having a length extending along the length of the respective side wall and end wall of the metallic container body 612, In other words, each of the two sheet metal blanks 650 (a and b) is foldable to define a substantially L shaped structure. The two L shaped structures are brought together to create a tubular structure that is configured to be mounted to the shallow base of the lower portion. One or more retainers 674 are used to secure the folded sheet metal blanks 650 (a and b) together with the walls 646 (a and b), 648 (a and b) of the shallow base. In the particular embodiment shown in Figure 13(a), the one or more retainers comprises C-shaped channel tubing 676 at the opposing ends of the metallic container body for securing the folded sheet metal blanks together. During assembly of the metallic container body as shown in Figure 13(b), the folded sheet metal blanks 650 (a and b) are received within the C-shaped channel tubing 676. To provide further strength to the metallic container body 612, the one or more retainers comprises separate rim portions 674 that are configured to be mounted to the upper edge of the folded sheet metal blanks 650 (a and b) to define the rim of the metallic container body 612. The separate rim portion provides a dual purpose of securing the folded sheet metal blanks together and providing an engaging surface for a grabber device of a load handling device to engage with the rim of the metallic container body. The one or more retainers 674, 676 can be cast to increase the strength of the metallic container body. The upper portion can be cast metal plates rather than being formed from a foldable sheet metal blank that are pivotably connected together. In the embodiments shown in Figure 11 (a and b), Figure 12, and Figure 13 (a and b), the upper sidewalls parts are pivotally connected to their respective end wall parts, e.g. by a living hinge. Instead of having a sheet metal blank comprising a sidewall part pivotally connected to its respective end wall part, the opposing sidewalls 770 (a and b) and end walls 772(a and b) of the metallic container body 712 can be formed as separate parts that are assembled together. In a seventh exemplary embodiment 710 of the present invention in Figure 14 (a and b) the walls 770 (a and b), 772 (a and b) of the upper portion are formed as separate parts, e.g. by stamping, and are subsequently fixedly connected together to form the upper sidewall parts and upper end wall parts. Connection of the separate wall parts of the upper portion can be by a snap fit joint. The separate parts of the upper portion are also fixedly connected to the lower opposing sidewall parts 746 (a and b) and lower end wall parts 748 (a and b) of the lower portion. In the collapsed or dismantled state as shown in Figure 14(a), the separate parts of the upper portion can be conveniently placed in a collapsed state within the shallow base 744 of the lower portion, and therefore the storage container occupies less storage space for transport. The separate upper sidewall 770 (a and b) and end wall 772 (a and b) parts can be stamped from a sheet metal blank and typically have a thickness in the range 0.5mm to 1mm. As with the other embodiments of the present invention shown in Figures 11 (a and b) to 13, the lower portion is formed by a deep drawn process or stamped from a sheet metal blank. At the point of use, the separate side wall parts 770 (a and b) and end wall parts 772 (a and b) of the upper portion can be connected to the lower portion, e.g. by a snap fitting joint, to create a box-like structure as shown in Figure 14(b). The upper edge of the shallow base comprises engaging portions 750 that snap fit with corresponding engaging portions of the upper sidewall and end wall parts. In the particular embodiment shown in Figures 14 (a and b), the engagement portions are integrally formed within the sidewall parts and end wall parts of the lower and upper portion of the metallic container body. The upper edge of the upper portion is inwardly turned to form a lip 766 having one or more apertures at the rim of the metallic container body for engagement with a grabber device of a load handling device. In use, the separate walls comprising the sidewall parts 770 (a and b) and end wall parts 772 (a and b) can be individually fixed to the walls of the shallow base 744 such that each of the opposing sidewalls of the metallic container body comprises a lower sidewall part and an upper sidewall part. Similarly, each of the opposing end walls of the metallic container body comprises a lower end wall part and an upper end wall part. In yet a further exemplary modification of the seventh embodiment of the present invention shown in Figure 14(c), the separate upper sidewall parts 771(a and b) and upper end wall parts 773(a and b) can be releasably connected together by a releasable latch mechanism so as to enable quick assembly and disassembly of the of the metallic container body 711 from the shallow base 744. The separate parts of the upper portion are also fixedly connected to the lower opposing side wall parts 747(a and b) and lower end wall parts 749(a and b) of the lower portion 744. In the particular embodiment shown in Figure 14(c) and more clearly shown in Figure 14(d), the upper sidewall parts 771(a and b) and upper end wall parts (773(a and b) are releasably connected together by cooperation of a toggle latch 760 with a hook at the respective distal or opposing ends of the upper sidewall parts and upper end wall parts. As shown in Figure 14(c), the opposing ends of the upper sidewall parts 771(a and b) comprises one or more toggle latches 760 that are configured to cooperate with hooks at the opposing ends of the upper end wall parts 773(a and b). Two toggle latches 760 are shown spaced apart at the opposing ends of the upper sidewall parts 771(a and b). Assembly of the metallic container body involves offering up the ends of the upper sidewall and end wall parts together and fixedly connecting them together by the toggle latches. The present invention is not limited to two toggle latches at the opposing ends of the upper sidewall parts and any number of toggle latches can be incorporated at the opposing ends of the upper sidewall parts. Equally, the toggle latches does not necessarily need to be at the opposing ends of the upper sidewall parts and can be at the opposing ends of the upper end wall parts. The advantage of the releasable latch is that it allows quick assembly and disassembly of the metallic container body 711. The individual walls parts 771(a and b), 773(a and b) can be formed from a sheet metal blank, e.g. stamp, or cast as metal plates. In the different examples of the metallic container body shown in Figures 14(a to d), the separate walls parts of the metallic container body can be stacked for storage or transit. In the particular embodiment shown in Figure 14(e), the separate parts of multiple metallic container bodies can be conveniently stacked 780 so taking up less storage space in comparison to them being in an assembled state. Additionally, by having separate parts that are assembled together at the point of use allows anyone of the separate parts to be easily replaced or changed should they become damaged, i.e. allows the provision of spare parts of the metallic container body. Alternatively, the upper sidewall parts 870 (a and b) and end wall parts 872 (a and b) of the metallic container body 812 can be pivotally attached to the corresponding lower sidewall parts 846 (a and b) and end wall parts 848 (a and b) of the shallow base or tray 844 by a hinge 880, e.g. living hinge, as shown in an exemplary eighth embodiment 810 of the present invention in Figure 15 (a and b). At the point of use, the upper sidewall parts 870 (a and b) and end wall parts 872(a and b) are rotated about their respective pivotable connection 880 as shown in Figure 15(b) such that adjacent ends of the upper sidewall parts 870 (a and b) and end wall parts 872 (a and b) join with to form a box-like structure. The joint between the adjacent ends of the upper sidewall parts 870(a and b) and end wall parts 872 (a and b) can be by a snap fitting joint, welding, riveting or even the use of an adhesive. As with the other embodiments of the present invention discussed above, the upper edge of the sidewalls and end walls at the rim of the metallic container body are inwardly turned to form a lip or flange 866 for releasable engagement with a grabber device. Alternatively, opposing ends of the upper sidewall parts 970 (a and b) and end wall parts 972 (a and b) can be joined together at the comers of the metallic container body 912 by one or more comer posts 930 as shown in a ninth exemplary embodiment 910 of the present invention in Figure 16 (a and b). The comer post 930, which can be cast, offers stmctural integrity to the walls of the metallic container body 912 from buckling when stacked with other storage containers in the grid framework stmcture. In the assembled state as shown in Figures 15(b) and 16(b), the sidewalls of the metallic container body comprise lower sidewall parts 946 (a and b) and upper sidewall parts 970 (a and b). Similarly, the end walls of the metallic container body 912 comprise lower end wall parts 948 (a and b) and upper end wall parts 972 (a and b). As with the other embodiments of the present invention shown in Figures 11 (a and b) to Figures 16 (a and b), the lower sidewall parts and end wall parts of the shallow base are outwardly inclined from the container bottom wall so that multiple metallic container bodies can be stacked on top of one another for ease of transport as shown in Figure 17. Having the upper sidewall parts and upper end wall parts being pivotally attached to their respective lower sidewall parts and lower end wall parts of the shallow base in the eighth and ninth embodiments shown in Figures 15 and 16 prevents any of the parts of the metallic container body from being lost during transit and allows easy assembly of the metallic container at the point of use. In contrast to forming the metallic container body from a deep drawn base and one or more folded sheet metal blanks, the lower and upper portion of the metallic container body can be formed from one or more patterned sheet metal blanks as shown in the tenth and eleventh exemplary embodiments of the present invention shown in Figures 18 and 19. For storage of grocery items, one or more flanges can be bent or folded at the edges of the sheet metal blank so that when erected, the flanges help to retain the sidewalls and end walls together in an upright position and to seal the joints between adjacent sidewalls and end walls of the metallic container body so as to prevent fluid escaping from the metallic container body. Alternatively or in combination with providing flanges at the joints between adjacent walls (sidewall and end wall) of the metallic container body, the interior space within the metallic container body can comprise a polymeric liner or an inner container to contain any leakage escaping from the contents of the storage container. In a tenth exemplary embodiment 1010 of the present invention shown in Figure 18 (a and b), the metallic container body 1012 is formed from two sheet metal blanks 105 0 (a and b) that are erected to form the container bottom wall 1015, the sidewalls 1016 (a and b) and end walls 1018 (a and b) of the metallic container body 1012. Erecting the metallic container body 1012 from one or more sheet metal blanks 1050 (a and b) has the advantage that the metallic container body can be flat packed for ease of transport and storage. In the particular embodiment shown in Figure 18 (a), the metallic container body 1012 is formed from a main section 1050a forming the container bottom wall 1015 and the opposing side walls 1016 (a and b) of the metallic container body 1012, and separate end plates 1050b forming the end walls 1018 (a and b) of the metallic container body 1012. The main section 1050a of the sheet metal blank comprises fold lines 1052, shown as dashed lines, running perpendicular to the longitudinal direction of the main section 1050a. At the point of use, the main section 1050a of the sheet metal blank is folded along the fold lines 1052 to create the container bottom wall 1015 and the opposing sidewalls 1016 (a and b) of the metallic container body 1012 having opposing open ends, i.e. folded so that the opposing side walls are substantially at right angles to the container bottom wall. End plates 1050b are then used to cover the opposing open ends to form a box-like structure as shown in Figure 18(b). The edge or distal ends of the main section 1050a and / or the end plates 1050b can be folded to create flanges 1054 for fixing the end plates 1050b to the folded main section 1050b of the sheet metal blank, i.e. fixing the end plate 1050b to the sidewalls 1016 (a and b). In the particular embodiment of the present invention shown in Figure 18, the opposing edges of the main section of the sheet metal blank is extended to form the flange 1054. Fixing the end plates 1050b to the flange 1054 of the sheet metal blank 1050a can be by welding, the use of an adhesive or other fixing means. In the particular embodiment shown in Figure 18 (b), the end plates 1050b are fixedly attached to the flange 1054 of the sheet metal blank 1050a by riveting. As with the other embodiments of the present invention described above, the main section 1050b and / or the end plates 1050a can comprise one or more vent holes 1020 which can be stamped into their respective sheet metal blank 1050a or end plates 1050b to create vent holes 1020 and / or handles. At least one edge or end of the main section of the sheet metal blank and the end plates can be inwardly or outwardly turned to create a lip 1064 at the rim around the periphery of the assembled box-like structure as shown in Figure 18 (b). As with the other embodiments of the present invention, the lip 1064 at the rim enables a grabber device of a load handling device to engage with the metallic container body when lifting a storage container from a stack. Alternatively, the metallic container body 1112 can be formed from a single part, more specifically from a single sheet metal blank 1150 as in an eleventh exemplary 1110 embodiment shown in Figure 19 (a and b). As shown in Figure 19 (a), the sheet metal blank 1150 comprises a central section forming the container bottom wall 1115 and opposing sidewall 1116 (a and b) and end wall 1118 (a and b) sections attached to the central section 1115, e.g. by a living hinge. Erection of the container metallic body comprises folding the opposing sidewall and end wall sections 1116 (a and b) at substantially right angles to the container bottom wall section 1115 to create a box-like structure as shown in Figure 19 (b). The sheet metal blank 1150 can comprise fold lines 1152 to assist with the folding of the opposing sidewall and end wall sections. The edges of the sidewall and / or end wall and / or container bottom wall portions can be folded to create a flange for joining the walls of the metallic container body together and to provide a leak proof container body. Alternatively, the interior space within the metallic container body can comprise a polymeric liner or an inner container to contain any leakage from the storage container. One or more retainers can be used to hold the opposing sidewalls and end walls in the upright position. Equally, the upper edges or ends of the opposing sidewalls and end walls can be turned, e.g. inwardly or outwardly, to form a lip 1164 at the rim of the box-like structure. The rim comprises one or more openings 1160 to enable a grabber device to engage with the metallic container body. As with the other embodiments of the metallic container body, one or more vent holes 1120 can be cut out in the sheet metal blank, e.g. by stamping or other means, to allow air to circulate within the metallic container body. In all of the embodiments utilising a sheet metal blank to fabricate the metallic container body, e.g. by a deep drawn process or folding a sheet metal blank, described with reference to Figures 8 to 19, the sheet metal blank can be coated with a polymeric lining in a laminated construction. This is particularly important where the contents of the storage container comprises food items so as to prevent contamination of the food items from exposure to the metallic container body. Additionally, the sheet metal blank can be corrugated by forming one or more ribs in the sheet metal blank, e.g. stamping, to improve the structural integrity of the erected metallic container body. In another exemplary embodiment 1210 of the present invention, the metallic container body 1212 comprising the container bottom wall 1215, opposing sidewalls 1216 (a and b) and end walls 1218 (a and b) can be cast as a single unitary body. For example, the metallic container can be die cast or alternatively, cast by an investment casting process. In a twelfth exemplary embodiment of the present invention shown m Figure 20, the metallic container body 1212 is die cast as a single unitary’ body. Whilst not providing a collapsible storage container as with the other embodiments discussed above, casting the metallic container body as a single unitary' body offers improved strength in a single part to prevent buckling of the walls of the metallic container body when placed in a stack. The metallic container body can be cast from aluminium having a wall thickness of about 1 to 1.5mm. However, other lightweight metals can be used to cast the metallic container body. Another advantage of casting the metallic container body is the provision of a leak proof container to prevent escape of fluid from the storage container. Vent holes 1220 can be formed in-situ when casting the metal container body or alternatively, the vent holes can be machined into the walls of the metallic container body once cast. The vent holes 1220 can be located a predetermined height above the container bottom wall to provide a leak proof base for capturing any spillage. Optionally, one or more ribs 1222 can be cast into the walls (sidewalls and end walls) of the metallic container body 1212 to improve tiie structural integrity of the metallic container body to withstand a load when in a stack. In the different embodiments of the present invention described above, the walls of the metallic container body are generally solid in the sense of being composed of a solid material and can comprise a coating or be laminated to ensure that the interior surface of the metallic container body is food safe. One or more wall stiffeners and / or inserts and / or comer posts can be incorporated into the metallic container body to improve the structural integrity of the storage container. In a yet further exemplary embodiment of the present invention, the walls of the metallic container body can be made hollow for the incorporation of a secondary filler material. In thirteenth exemplar}' embodiment 1310 of the present invention shown in Figure 21, the opposing sidewalls 1316 (a and b) and end walls 1318 (a and b) and optionally, the container bottom wall 1315 are hollow. The hollow' space within the walls of the metallic container body can be filled with a filler material to improve the properties of the metallic container body 1312. For example, the filler material can be a polymeric foam that provides sound proofing acoustic properties to the storage container. Optionally, the filler material can be fireproof. Typical fireproof materials that are lightweight and fireproof include but are not limited to vermiculite. The filler material can also improve the structural properties of the storage container to withstand loads when held in a stack. Whilst not shown in Figure 21, one or more ribs can be formed into the walls of the storage container to improve the structural integrity of the storage containers. The joint between adjacent sidewalls and end walls can be fixed together by welding, use of an adhesive, or rivets, or simply a tongue and groove joint. The container bottom wall, sidewalls and end walls can be separate parts that are assembled together at the point of use for ease of transport. Where the contents of the storage containers are grocery items, it is essential that the grocery items are stored in containers that comply with food safety standards. There are limited types of metals that can be used in the fabrication of the metal container body that would comply with food safety standards. These include various stainless steel materials such as 304 stainless steel. However, fabricating the metal container body from stainless steel suffers from the problem that the metal is of a lower density than other type of metals such as low'er grade steel or aluminium and is generally expensive. As a result, the walls of the metal container body w'ould be relatively thin compared to its counterpart plastic variant of a similar weight in the industry. Ilie areas of tire storage container that are susceptible to fire are the exterior surface of the storage container. As the metal container body is fire resistant, the metal container body can function as a fire resistant body forming a non-combustible enclosure so as to prevent or limit the ingress of fire into the interior space of the storage container. Since the metal container body can function as a non-combustible enclosure and to comply with food safety standards for the storage of grocery items, the fire resistant body can comprise a liner that is formed from food grade material. Examples of food grade materials include but is not limited to various food grade plastic material, cellulose based materials such as paper or cardboard. To make the liner moisture resistant, the paper or cardboard liner can be impregnated with or coated a food safe wax. At least a portion of the interior surface of the fire resistant body comprises a liner 1420, 1422 formed from a food safe or grade material in the sense that the height of the liner 1420 partially extends the full height of the metal container body 1412 as shown in Figures 22 and 23 or the full height liner 1422 of the metal container body 1412 as shown in Figure 24 and 25. Ilie use of a liner 1420, 1422 that is compliant to storing grocery items allow s different materials to be used for the fire resistant body. Whilst in the particular embodiments described above, the first resistant body 1412 can comprise metal other fire resistant material can be used in the fabrication of the fire resistant body including various ceramic materials and various fire resistant plastic materials, e.g. plastic materials comprising a fire resistant additive. This fire resistant body can comprise lower density material but possessing the same structural integrity and load bearing capacity as the current plastic based storage containers. As a result, the walls of the fire resistant body can be made thicker so giving the walls of the storage container sufficient load bearing capacity to support the weight of multiple storage containers in a stack. In the particular embodiment 1410 of the present invention shown in Figure 22, the fire resistant body comprises a metal container body 1412 comprising a bottom wall 1415, and upwardly standing opposing sidewalls 1416a, 1416b and end walls 1418a, 1418b. The metal container body 1412 is partially lined with a liner 1420. In the particular embodiment of the present invention shown in Figure 23, the liner 1420 is a tray or a shallow base formed as an insert in the metal container body 1412. The tray 1420 is formed from a food grade material and is leak proof to prevent leakage of juices from the grocery items such as meat. There are various examples of forming a leak proof liner. These include but is not limited to blow moulding, thermoforming a signal piece liner where the liner comprises a food grade plastic material. In the case where the liner comprises a cellulose base material such as paper or cardboard, the liner can be formed from a foldable sheet blank that is impregnated or coated with a wax material. Ilie height of the liner does need to extend the full height of tire metal container body and can partially extend the full height of the metal container body. In the example shown in Figure 23, the height of the tray 1420 extends half the height of the metal container body 1412. This is considered acceptable where the grocery items stored in the storage container only contacts the bottom wall and partially along the opposing sidewalls and end walls of the storage container and / or is only required to prevent leakage of juices of the grocery items contaminating other grocery items in nearby storage containers. However, this is not to say that the liner can extend the full height of the metal container body. Figure 24 and 25 show's an example where the liner 1422 extends the full height of the metal container body 1412. Again, the liner 1422 functions as an insert that be placed inside the metal container body as shown m Figure 24. Having a liner based on paper or cardboard allows the liner to be disposable allowing different types of grocery items to be stored m the metal container body and limits the need to continually wash the interior surface of the storage container. In the case, where the storage container comprises a metal container body, particularly low' grade steel, the use of water to wash the storage container has the tendency to corrode or rust the metal container body making the metal container body unusable for storage of grocery' items. The use of a liner composed of a food grade material removes the need to wash the metal container body and thereby, prolongs the life of the metal container body. Whilst the preferred embodiments of the present invention have been described in detail above, it should be understood that various modifications of the storage container encompassing different features described above, and different combinations of features described in relation to different embodiments, are applicable within the scope of the present invention as defined in the claims. Further features of the invention may be described with reference to the following numbered clauses: Clause 1. A storage and retrieval system comprising: a) a track system comprising a first set of parallel rails or tracks and a second set of parallel rails or tracks running transversely to the first set of parallel tracks in a substantially horizontal plane to form a grid pattern comprising a plurality of grid spaces or grid cells, b) a plurality of stacks of storage containers located beneath the track system, each storage container of the plurality of stacks of storage containers comprises a container bottom wall and upwardly standing opposing sidewalls and end walls arranged in a box-like structure with an open end for receiving one or more items within the box-like structure, and wherein each stack of the plurality of stacks of storage containers occupies a single grid space or grid cell, characterised in that one or more of the plurality of stacks of storage containers comprises a fire resistant container body forming a non-combustible enclosure and at least a portion of the interior surface of the fire resistant body comprises a liner formed from a food grade material. Clause 2. The storage and retrieval system of clause 1, wherein the fire resistant body is a metal container body. Clause 3. The storage and retrieval system of clause 2, wherein at least a portion of the metallic container body is formed from a folded sheet metal blank. Clause 4. The storage and retrieval system of clause 2 or 3, wherein at least a portion of the metallic container body is formed from a deep drawn sheet metal blank. Clause 5. The storage and retrieval system of clause 2 or 3, wherein at least one of upwardly standing opposing sidewalls and / or end walls are separable. Clause 6. The storage and retrieval system of any of the preceding clauses, wherein the liner comprises a food grade plastic material and / or cellulose base material. Clause 7. The storage and retrieval system of clause 6, wherein the cellulose base material is coated or impregnated with a wax material. Clause 8. The storage and retrieval system of clause 6 or 7, wherein the cellulose based material is paper or cardboard. Clause 9. The storage and retrieval system of clause 8, wherein the liner is formed from a folded paper or cardboard blank. Clause 10. The storage and retrieval system of any of the preceding clauses, wherein the liner is disposable. 5 Clause 11. The storage and retrieval system of any of the preceding clauses, wherein the liner is a shallow base or tray. Clause 12. The storage and retrieval system of any of the preceding clauses, wherein the liner is a leak proof container. .0 Clause 13. The storage and retrieval system of clause 12, wherein the leak proof container is a one piece thermoformed container.

Claims

1. A storage and retrieval system comprising:a) a track system comprising a first set of parallel rails or tracks and a second set of parallel rails or tracks running transversely to the first set of parallel tracks in a substantially horizontal plane to form a grid pattern comprising a plurality of grid spaces or grid cells,b) a plurality of stacks of storage containers located beneath the track system, each stack of the plurality of stacks of storage containers occupies a single grid space or grid cell and wherein each storage container of the plurality of stacks of storage containers comprising a metallic container body formed from a main section comprising a container bottom wall and upwardly standing opposing sidewalls of the metallic container body and separate end plates forming the end walls of the metallic container body, said main section is formed from a sheet metal blank folded along fold lines to create the container bottom wall and the opposing sidewalls of the metallic container body having opposing open ends, said separate end plates cover the opposing open ends to form a box-like structure,c) one or more robotic load handling devices operative on the track system for moving and lifting one or more storage containers of the plurality of stacks of storage containers stacked in the stacks, each of the one or more robotic load handling devices comprisingi) a container-receiving space;ii) a drive mechanism for moving the robotic load handling device on the track system and;iii) a lifting mechanism for lifting and lowering at least one of the plurality of storage containers from at least one stack of the plurality of stacks of storage containers such that when positioned above the at least one stack of the plurality of stacks of storage containers occupying a grid cell, the lifting mechanism is configured to lift the at least one storage container from the at least one stack of the plurality of stack of storage containers into the container-receiving space, said lifting mechanism comprises a grabber device configured, in use, to releasably grip the storage container and lift the storage container from the at last one stack of the plurality of stacks of storage containers into the container-receiving space.

2. The storage and retrieval system of claim 1, wherein the grabber device comprises at least two gripper elements engageable with a rim at the mouth of the storage container.

3. The storage and retrieval system of claim 2, wherein the rim comprises one or more openings such that each of the one or more gripper elements are receivable into the one or more openings of the rim.

4. The storage and retrieval system of claim 2 or 3, wherein the rim extends around the mouth of the storage container and comprises an inwardly or outwardly turned projecting lip from the sidewalls and / or the end walls for supporting the bottom container wall of an adjacent storage container above in a stack.

5. The storage and retrieval system of any of the preceding claims, wherein the metallic container body of the storage container comprises a plurality of stops protruding inwardly into the mouth of the storage container and located at diagonal opposing comers of the storage container for supporting the bottom container wall of an adjacent storage container in a stack, said plurality of stops are spaced apart above the container bottom wall so as to prevent fouling one or more items in the storage container by the container bottom wall of an adjacent storage container above in the stack.

6. The storage and retrieval system of any of the preceding claims, wherein at least one of the upwardly standing opposing sidewalls and / or end walls comprises a plurality of vent openings.

7. The storage and retrieval system of any one of the preceding claims, wherein at least one of the upwardly standing sidewalls is fixedly connected to at least one of the upwardly standing end walls.

8. The storage container of any one of the preceding claims, wherein the edges of the main section and / or the end plates are folded to create flanges for fixing the end plates to the folded main section of the sheet metal blank.

9. The storage container of claim 8, wherein the end plates are fixed to the flange of the folded main section by welding.

10. The storage and retrieval system of any one of the preceding claims, wherein the storage container comprises one or more wall stiffeners configured to support at least one of the upwardly standing opposing sidewalls and / or at least one of the upwardly standing opposing end walls of the metallic container body.

11. The storage and retrieval system of claim 11, wherein the one or more wall stiffeners are cast.

12. The storage and retrieval system of any one of the preceding claims, wherein at least one of the container bottom wall, upwardly standing opposing sidewalls and the end walls of the metallic container body comprises a hollow portion and a fdler material disposed in the hollow portion.

13. The storage and retrieval system of claim 12, wherein the fdler material is an insulation material and / or a fire resistant material.

14. The storage and retrieval system of any one of the preceding claims, wherein the metallic container body of each of the plurality of storage containers comprises an inner surface and an outer surface, and wherein the inner surface comprises a polymeric coating.

15. The storage and retrieval system of any one of the preceding claims, wherein at least a portion of the container bottom wall and / or opposing sidewalls and / or opposing end walls is reinforced by one or more ribs.

16. A storage container constructed to be stacked in a storage and retrieval system, said storage and retrieval system comprising a track system comprising a first set of parallel rails or tracks and a second set of parallel rails or tracks running transversely to the first set of parallel tracks in a substantially horizontal plane to form a grid pattern comprising a plurality of grid spaces 5 or grid cells, the storage container comprising a metallic container body formed from a main section comprising a container bottom wall and upwardly standing opposing sidewalls of the metallic container body and separate end plates comprising the end walls of the metallic container body, and a rim comprising one or more openings for receiving one or more gripper elements of a lifting mechanism; wherein said main section is formed from a sheet metal blank 10 folded along fold lines to create the container bottom wall and the opposing sidewalls of the metallic container body having opposing open ends, said separate end plates cover the opposing open ends to form a box-like structure.

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