Storage Systems and Storage Containers

Abstract

A method for manufacturing a storage container for storage in a stack in a grid framework structure comprising a plurality of storage columns, each of the plurality of storage columns configured to store a stack of storage containers, the method comprising: A) forming a lower portion of the storage container by: i) stamping or drawing a sheet metal blank (185) in a drawing die (184) to form a tray-shaped preform (178) comprising a base (172) having a raised rim (180) and a flange (182), and ii) turning the flange (182) to define a connecting surface extending in the same direction as the raised rim (180) of the tray-shaped preform (178) to form a container having a predetermined depth; B) iii) forming an upper portion of the storage container by stamping side walls and / or end walls from one or more separate sheet metal blanks; and C) attaching the lower portion to the upper portion by attaching the side walls and end walls to the connecting surface of the container.

Description

[Technical Field]

[0001] The present invention relates to the field of storage systems comprising load handling devices operable on trucks 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 technology]

[0002] Some commercial and industrial activities require systems that allow for the storage and retrieval of a large number of different products. One known type of system for storing and retrieving items in multiple product lines involves placing storage containers (also known as bins or totes) on top of each other in stacks, with the stacks arranged in rows. The storage containers are removed from the stacks and accessed from above by a load handling device, eliminating the need for aisles between the rows and thereby allowing a large number of containers to be stored in a given space.

[0003] As shown in FIGS. 1 and 2 , storage containers 10, also known as bins or totes, are stacked on top of each other to form stacks 12. The stacks 12 are arranged in a grid framework structure 14 in a warehouse or manufacturing environment. The grid framework is made up of a plurality of storage columns or grid columns 11. Each grid in the grid framework structure has at least one storage column 11 for storing a stack of containers. FIG. 1 is a schematic perspective view of the grid framework structure 14, and FIG. 2 is a top view showing a single stack 12 of containers 10 arranged within the framework structure 14. Each container or receptacle 10 typically holds multiple product items (not shown), which may be the same or different product types depending on the application. Each container 10 may be used, for example, to store grocery items (i.e., food items). Furthermore, the receptacle 10 may be physically subdivided to accommodate multiple different inventory items.

[0004] The grid framework structure 14 comprises a plurality of upright members or columns 16 that support horizontal members 18, 20. A first set of parallel horizontal grid members 18 are arranged perpendicular to a second set of parallel horizontal grid members 20 to form a grid structure that lies in a substantially horizontal plane and is supported by the upright members 16. The members 16, 18, 20 are typically fabricated from metal and are typically welded or bolted together, or a combination of both. The storage containers 10 are stacked between the upright members 16 of the grid framework structure 14, so that the grid framework structure 14 prevents horizontal movement of the stack 12 of storage containers 10 and guides vertical movement of the storage containers 10.

[0005] The top level of the grid framework structure 14 includes a track system 15 comprising a plurality of rails or tracks 22 arranged in a grid pattern across the top of the stacks 12. Referring additionally to FIG. 3 , the rails 22 support a plurality of load handling devices or robotic load handling devices 30. A first set 22a of parallel rails 22 guides movement of the robotic load handling devices 30 in a first direction (e.g., the X direction) across the top of the grid framework structure 14, and a second set 22b of parallel rails 22 disposed perpendicular to the first set 22a guides movement of the load handling devices 30 in a second direction (e.g., the Y direction) perpendicular to the first direction. In this manner, the rails 22 enable movement of the robotic load handling devices 30 laterally in two dimensions within the horizontal XY plane, so that the load handling devices 30 can be moved to a position above any of the stacks 12. The track system 15 may be integrated into the grid structure in the sense that the first and second sets of tracks are integrated into the first and second sets of grid members, respectively. Alternatively, the track system 15 may be separate from the grid structure in the sense that the first and second sets of tracks are mounted to the first and second sets of grid members, respectively.

[0006] Each load handling device 30 comprises a car body 32 arranged to ride in the X and Y directions on the tracks or rails 22 of the grid frame structure 14 above the stack 12 (see FIG. 4). FIGS. 4 and 5 show a load handling device 30 as described in PCT Patent Publication No. WO2015 / 019055 (Ocado Innovation Limited) and International Patent Application No. WO2015 / 140216 (Ocado Innovation Limited), comprising a car body 32 fitted with a lifting mechanism 33 comprising a winch or crane mechanism 35 for lifting a storage container or receptacle 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 vertically and connected near or to the four corners of the grabber device 39 (one tether near each of the four corners of the grabber device) for releasable connection to the storage container 10. The grabber device 39 is configured to grasp the top of the storage container 10 and lift the storage container 10 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.

[0007] To grip the container 10, the grabber device 39 includes four locating or guide pins 42 near or at each corner of the grabber device 39 that fit into corresponding notches or holes 44 formed in the four corners of the storage container 10, and four gripper elements 46 located on the bottom side of the grabber device 39 for engaging a rim 48 of the storage container 10 (see FIG. 6 ). The locating pins 42 help properly align the gripper elements 46 with the corresponding holes 49 in the rim 48 of the container. In the example shown in FIG. 7 a, each of the gripper elements 46 includes a pair of foldable wings 50 that are receivable in the corresponding holes 49 in the rim 48 of the storage container, and an open, extended configuration that is larger in size than the holes 49 in the rim 48 of the storage container 10 in at least one dimension so as to lock onto the storage container 10 (see FIG. 7 b). The wings are driven to the open configuration by a drive gear (not shown). More specifically, the head of at least one of the wings includes a plurality of teeth that mesh with a drive gear, so that when the gripper element 46 is actuated, rotation of the drive gear rotates the pair of wings from a folded configuration (FIG. 7a) to an open, extended configuration (FIG. 7b).

[0008] The car body 32 comprises an upper and lower part (see Figures 5(a) and 5(b)). The lower part is fitted with two sets of wheels 34, 36, which run on rails on top of the framework structure of the storage system. The upper part of the car body 32 may house most of the bulky components of the load handling device. Typically, the upper part of the car body houses a drive mechanism for driving both the wheels and the lifting mechanism, along with an on-board rechargeable power source for powering the drive mechanism and the lifting mechanism.

[0009] The underside of the car body 32 includes wheel assemblies that are driven to allow the vehicle to move in the X and Y directions along the rails, respectively. A first set of wheels 34, consisting of a pair of wheels 34 at the front of the vehicle 32 and a pair of wheels 34 at the rear of the vehicle 32, are positioned to engage 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 positioned to engage 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 off its respective rail, thereby allowing the vehicle to move in a desired direction. With the first set of wheels 34 engaged with the first set of tracks or rails 22a and the second set of wheels 36 lifted off the tracks or rails 22, the wheels 34 can be driven by a drive mechanism (not shown) housed within 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 is lifted off the tracks or rails 22b and the second set of wheels 36 is lowered to engage the second set of tracks or rails 22b. A drive mechanism may then be used to drive the second set of wheels 36 to achieve movement in the Y direction. One or both sets of wheels may be moved vertically to lift each set of wheels off its respective rail, thereby allowing the vehicle to move in a desired direction on the track system.

[0010] The wheels are positioned around the periphery of a cavity or recess in the lower section known as a container-receiving recess 40. The recess 40 is sized to accommodate the storage container or receptacle 10 when it is lifted by a crane mechanism with a winch, as shown in Figures 5(a and 5b). When in the recess, the container is lifted off the lower rails so that the load handling device can move laterally to different locations. Although the container-receiving space 40 is shown in Figure 4 as being located within the vehicle body 32, the container-receiving space can be located below a cantilever, as described in WO2019 / 238702 (Autostore Technology AS).

[0011] Upon reaching the target location, e.g., another stack, an access point in a storage system, or a conveyor belt, the receptacle or storage container may be lowered from the container receiving space and released from the grabber device 39. In this manner, under the control of a centralized control utility (not shown), one or more robotic load handling devices 30 may move around on top of the stacks 12 on the frame structure 14, as shown in Figure 3. Each robotic load handling device 30 is provided with a lifting mechanism 33 for lifting one or more receptacles 10 from the stack 12 to access the required items stored therein.

[0012] The robotic load handling device 30 retrieves the container 10 containing inventory items (not shown) therein and transports the container 10 to a picking station (not shown) where the required inventory items 28 are removed from the container 10 and placed into the container 10 with a shipping container DT. It is important to note that the shipping container DT may fit within the container 10. The container 10 may contain inventory items or may comprise a shipping container DT. Additionally, the shipping container DT may comprise at least one bag and the inventory items are picked directly into the bag at the picking station (not shown).

[0013] A typical storage and retrieval system 1 is shown in FIG. 3 and includes multiple load handling devices 30 operating on a grid above stacks 12. FIGS. 1 and 3 illustrate containers 10 in stacks 12 within the storage system. It will be appreciated that there may be numerous storage containers or containers 10 in any given storage system, many different items may be stored in the containers 10 in the stacks 12, and each container 10 may house a different category of inventory item within a single stack 12. Typically, each container 10 must be capable of withstanding the load of multiple containers 10 in the stack. The load of a container stack is supported by the maximum load of 20 fully loaded containers. A fully loaded container weighs approximately 35 kg, of which 5 kg represents the weight of a single container. For example, a stack of 20 containers 10 would represent a load of 700 kg or 6,867 N. One or more ribs on the opposing side and end walls strengthen the side and end walls to prevent them from buckling under such loads in the stack.

[0014] Typically, the container 10 is largely made of thermoplastic material and is either injection molded or blow molded. Known thermoplastic materials commonly used to form storage containers include polyolefins, such as polypropylene or polyethylene (e.g., high-density polyethylene (HDPE)), acrylonitrile butadiene styrene (ABS), and polycarbonate (including their copolymers). However, a problem with such plastic materials is that they are flammable and emit toxic fumes. If a fire were to break out within the storage and retrieval system, the flammability and exothermic nature of the container 10 material would result in the fire spreading throughout the storage and retrieval system, posing a risk to life. Not only is the container 10 flammable, but the combustion fumes emitted from the burning thermoplastic material are highly toxic and include benzene, a known carcinogen. Inhalation of fine particles resulting from burning debris can cause respiratory irritation. As a result, extensive fire prevention methods and systems, such as sprinklers and smoke / heat detection units, are incorporated into storage and retrieval systems to prevent the rapid spread of fire. Although efforts have been made to prevent the rapid spread of fire, with the containers 10 playing a major role in the spread of fire, there is still the problem of fire spreading throughout the storage and retrieval system. Storage containers should not only be fire resistant, but also have sufficient structural rigidity to allow them to be stacked on top of each other in the storage and retrieval system. Typically, a full storage container weighs a maximum of 35 kg. 30 kg represents the weight of the stock or item, and 5 kg is the typical weight of a storage container. For a stack with 20 full storage containers, the load that the storage containers in the stack would have to withstand would be 700 kg (6,867 Newtons).

[0015] WO2022 / 161863 (Autostore Technology AS) teaches a storage container for an automated storage and retrieval system. The storage containers are configured to be stacked in a stack of storage containers, where a lower storage container supports an upper-positioned storage container(s) (106). The storage container comprises a base and four sides, each hingedly connected to an edge of the base by a live hinge. Four corner posts are configured to horizontally interconnect pairs of adjacent sides when the sides are positioned approximately 90 degrees relative to the base and each other. The base and sides of the storage container comprise sheet metal material, which is provided as a blank from which the base and four sides are formed. However, WO2022 / 161863 (Autostore Technology AS) does not address the problem of providing a leak-proof storage container, particularly where the contents of the storage container are foodstuffs or food items that are prone to spilling and may contaminate other food items in the storage container or adjacent storage containers in a stack.

[0016] This has led to a need for fire resistant storage containers that can be stacked in a storage and retrieval system and that do not suffer from leakage problems when storing food items. Summary of the Invention

[0017] The present invention alleviates the above problems by forming a storage container that includes a container or tray formed as a single, integral body to capture any leakage resulting from spillage of any of the contents of the storage container. Because the container is formed as a single, integral body, the container may be defined as a unitary container. The advantage of forming the base portion of the storage container as a single, integral body is that it provides greater assurance of leak-proofness rather than relying on the connections between the walls of the storage container being leak-proof. The unitary container forms the base portion or lower part of the storage container and provides the best protection against leakage. Side and end walls are then attached to the base portion to form the upper part of the storage container. The upper part of the storage container confines the contents of the storage container within the boundaries of the storage container and prevents the contents from spilling out of the storage container. By assembling the lower part including the container to the upper part including the side and end walls, a box-like structure having a predefined depth is formed.

[0018] Processing methods for making containers include stamping or punching a single sheet metal blank through a forming die corresponding to the container shape, or drawing the sheet metal blank into the forming die. In both forming methods, the sheet metal blank is plastically deformed by the mechanical action of the forming die, particularly in the areas around the corners of the container. The degree of plastic deformation due to the stamping or drawing process depends greatly on the sharpness of any angles formed in the container or formed with a very small radius. If the container is approximately rectangular, the plastic deformation of the sheet metal blank occurs mostly around the corners of the container. The sharper the corners of the container, in the sense of forming approximately 90° corners, the greater the plastic deformation because the sheet metal blank will experience more stretching or elongation compared to other areas of the container, such as the container wall. One of the negative consequences of plastic deformation during the forming process is wrinkling of the sheet metal, particularly in the areas around the corners. In the worst case scenario, stretching of the sheet metal at the corners of the container can excessively exceed the sheet metal's yield strength, resulting in localized thinning of the sheet metal wall to the point where the sheet metal may tear or split, i.e., reach its breaking point. Excessively exceeding the sheet metal's yield strength during the forming process is particularly problematic when cold-drawing a sheet metal blank because the ductility of the metal decreases at lower temperatures. Cold-drawing a sheet metal blank tends to be the most favorable forming operation due to the small number of operations required to process the sheet metal blank and the high production speed of storage containers. Considering that a typical grid framework structure can hold thousands of storage containers, the cost and speed of manufacturing storage containers are crucial factors in the running costs of a storage and retrieval system. As a result, a manufacturing method that limits the number of processing steps in the fabrication of storage containers is needed.

[0019] To overcome the limitations of cold-forming sheet metal blanks into predefined shapes, sheet metal blanks are typically plastically deformed at elevated temperatures to increase the sheet metal blank's plasticity, a process known in the art as superplastic forming (SPF). Superplasticity in metals is defined by high tensile elongation and the ability to undergo extreme elongation at a specific temperature and strain rate. This typically involves heating the sheet metal blank to high temperatures to increase the metal's plasticity. For this reason, superplastic forming is used to produce parts that are difficult to form using conventional cold working processes. However, creating storage containers using superplastic forming tends to require relatively long forming cycle times, which can be as long as 30 minutes. Given that storage containers must be manufactured in large quantities, such forming techniques may not be ideal for forming storage containers for use in storage and retrieval systems.

[0020] When a storage and retrieval system is used to store food items, it is essential that the container has sufficient depth to capture any spillage from the food ingredients. Spillage may be the result of juices, beverages, or other liquids seeping out of the stored food items. The recommended leak capacity or leak-proof capacity of a storage container to capture any leakage from the food items as a result of a spill is approximately 20-30 liters. Considering that a typical storage container used in a storage and retrieval system has dimensions of 648 mm in length, 448 mm in width, and 362 mm in height to capture and hold 20-30 liters of fluid, this corresponds to a container having a depth in the range of 90 mm to 95 mm. Because the depth of the container is much less than the length and width of the container, the container is formed into a shallow container.

[0021] The amount of plastic deformation experienced by the sheet metal blank increases as the depth of the container increases because greater force is required to draw the sheet metal blank to greater depths. However, it is preferable that the container walls be substantially uniform, rather than locally thinning in one or more areas of the storage container, weakening the storage container. An obvious solution to providing a container with sufficient leakage capacity would be to form the container with more rounded corners to reduce the amount of excessive plastic deformation experienced by the sheet metal during the forming process. However, one of the primary requirements for storage containers for use in storage and retrieval systems is the ability to stack the storage containers in storage columns in a grid framework structure so as to allow a robotic load handling device operable on the grid framework structure to engage with the storage container and lift it from the stack or storage container. When stacking storage containers in a grid framework structure, it is essential that the base or bottom wall of the storage container rests on the rim of the adjacent storage container below in the stack, allowing a load handling device operable on the grid framework structure to properly engage the storage container. In order for the grabber devices of the load handling device to properly engage with the storage containers in the stack, it is important that the storage containers are level. For a storage container to be level in the stack, ideally, the base or bottom of the storage container should sit squarely on the rim of the storage container below it in the stack. Because the container forms the bottom of the storage containers, forming the container with more rounded corners suffers from the problem that one or more of the corners of the storage container will not sit squarely on the rim of the adjacent storage container below it in the stack and, in the worst case scenario, will fall into the mouth of the storage container below it in the stack. Considering that a stack can hold as many as 21 storage containers, any one storage container that fails to properly sit on the rim of the adjacent storage container below it in the stack has the potential to cause several of the storage containers to become stuck together.This, in turn, would prevent a load-handling device operable on the grid framework structure from properly engaging a storage container and, when engaged, separating the storage container from adjacent storage containers in the stack. One solution would be to draw a sheet metal blank multiple times to different depths by feeding the drawn part through different drawing dies of increasing depth. However, this not only increases the number of processing steps in the fabrication of a storage container, but repeatedly feeding the drawn part through different dies is not suitable for automating the fabrication process. Furthermore, this also increases the risk of damage to the drawn part each time it is fed through another die due to the need to continuously remove the drawn part from the previous die in the fabrication process.

[0022] In order to provide a storage container formed from a container having the correct depth for the purpose of providing a leak-proof storage container, and allowing it to be stacked without suffering from the problems discussed above, the lower portion of a storage container according to the present invention is formed from at least a two-stage process. More specifically, the present invention provides a method of manufacturing a storage container for storage in a stack in a grid framework structure comprising a plurality of storage columns, each of the plurality of storage columns being configured to store a stack of storage containers, the method comprising: A) i) stamping or drawing a sheet metal blank into a drawing die to form a tray-shaped preform having a base with a raised rim and flange; ii) turning the flange to define a connecting surface extending in the same direction as the raised rim of the tray-shaped preform to form a container having a predefined depth; forming a lower portion of the storage container by B) iii) stamping the side walls and / or end walls from one or more separate sheet metal blanks; forming a top portion of the storage container by C) attaching the lower portion to the upper portion by attaching the side and end walls to the connecting surfaces of the container; The present invention provides a method comprising:

[0023] Stamping or drawing a sheet metal blank into a drawing or forming die to form a tray-shaped preform with a base or bottom wall having a raised rim and flange, followed by turning the flange to form a container having a predetermined depth, allows the container to be formed to a predetermined leakage capacity by a cold forming process. As a result, the container can be formed to a given depth without excessively exceeding the break point of the sheet metal, particularly at the corners of the container. Cold forming of the sheet metal blank to form the tray-shaped preform can be used to the extent that the break point of the sheet metal is not reached or exceeded when forming tray-shaped preforms with tight radii, particularly at the corners. Rather than re-drawing the tray-shaped preform to a greater depth, the flange can be turned to increase the depth of the tray-shaped preform to increase the leakage capacity of the tray-shaped preform. The flange can be turned at the junction between the raised rim and flange of the tray-shaped preform to increase the depth of the tray-shaped preform. The combination of the stamping / drawing process and the flange turning allows the container to be formed with sharp corners and the required leakage capacity to hold the liquid, which would not be possible if the container were completely stamped or drawn in a single operation from a single cold sheet metal blank to a predefined depth. Optionally, the corners of the tray-shaped preform are rounded with a radius in the range of 5 mm to 10 mm, more specifically in the range of 5 mm to 8 mm. Optionally, the sheet metal blank has a thickness in the range of 0.5 mm to 1.0 mm.

[0024] The drawing process relates to a process in which a sheet metal blank is drawn into a die cavity by the mechanical action of a punch. The drawing die comprises a retaining die member, an upper die member, and a lower die member, at least one of the upper and lower die members comprising a punch and the opposite die member comprising a die cavity. Optionally, the method further comprises using the retaining die member with the punch to control the amount of the sheet metal blank drawn into the die cavity.

[0025] As a result of the drawing process, the flange extends outwardly around the peripheral open edge of the raised rim. To turn the flange to define a connecting surface for connecting the side and end walls in the top of the storage container, the flange is preferably turned by turning the flange inwardly so that the flange extends in the same direction as the raised rim of the tray-shaped preform.

[0026] During the drawing process, a sheet metal blank is clamped in a holding die member, and a punch is mechanically drawn into the sheet metal, causing the sheet metal blank to assume the shape of the punch with a raised rim. One of the results of drawing the sheet metal blank is that the sheet metal stretches as the amount of sheet metal is gradually drawn into the die cavity. This stretching results in flashing extending from the raised rim around the holding die. The flash can vary in length depending on the stretching experienced by the sheet metal in the die cavity. Optionally, the method further includes trimming the flash to form a flange with a trim-cutting die comprising a trim-cutting punch and a positioning die member for supporting the tray-shaped preform, where the flash is trimmed by moving a corner-cutting punch relative to the positioning die member to form the flange. Optionally, the trim-cutting punch can be integrally formed with the drawing die, for example, as part of the die cavity. Integrating the trim-cutting punch into the die cavity allows the flash trimming to be performed using the same tool as the drawing die. From this, a punch for drawing a sheet metal blank into a tray-shaped preform can function as a holding die member for supporting the tray-shaped preform, and a trim-cutting punch integrated into the die cavity subsequently trims the flash to form a flange for turning. Optionally, the trimming of the flash can be performed in a separate tool. From this, the method can comprise feeding the tray-shaped preform to a trim-cutting die comprising a trim-cutting punch and a positioning die member for supporting the tray-shaped preform, the method further comprising trimming the flash by moving the trim-cutting punch relative to the positioning die member to form the flange.

[0027] The rate and amount of sheet metal drawn into the die cavity varies depending on the shape of the die cavity. In the case of a cube-shaped die cavity, a larger proportion of the sheet metal is drawn at the sides and ends of the tray-shaped preform compared to the corners of the tray-shaped preform. This results in uneven flashing around the peripheral open edge of the container rim, particularly at the flange corners. This is a result of more material flowing at the flange corners during the turning process. The method further comprises trimming the flashing corners with a trim corner-cutting die comprising a corner-cutting punch and a positioning die member for supporting the tray-shaped preform, where the flashing corners are trimmed by moving the corner-cutting punch relative to the positioning die member. Like the trim cut punch, the corner-cutting punch is optionally formed integrally with the drawing die. Alternatively, the flashing corner trimming can be performed in a separate tool. Therefore, optionally, the method further comprises feeding the tray-shaped preform to a trim corner-cutting die comprising a corner-cutting punch and a positioning die member for supporting the tray-shaped preform, and the method further comprises trimming the corners of the flash by moving the corner-cutting punch relative to the positioning die member.

[0028] The phrase "turned" encompasses the process of bending the sheet metal at the junction between the raised rim and the flange so that the sheet metal lies in a vertical plane, thereby increasing the depth of the tray-shaped preform. Optionally, the flange i) surrounding the tray-shaped preform with a wiping die such that the flange extends at least partially across the wiping die; ii) moving the wiping die against the tray-shaped preform to turn the flange; It can be turned by.

[0029] An example of turning a flange on an industrial scale is by using a wiping die (also known as edge bending) which comprises a positioning die member and a wiping die member. i) holding a preformed preform in a positioning die member such that a flange extends outwardly from the positioning die member; ii) moving the wiping die member relative to the positioning die member to turn the flange; Equipped with.

[0030] Optionally, the wiping die member is integrally formed with the drawing die, so that the wiping process of the flange can be performed using the same tool as the drawing process. Alternatively, the wiping process can be performed by: i) feeding a tray-shaped preform onto a wiping die member, the wiping die member comprising a positioning die member and a wiping die member, the wiping die member extending outwardly from the positioning die member; ii) moving a wiping die member relative to a positioning die member to turn the flange; This can be done in a separate wiping tool by

[0031] Depending on the shape of the storage container, the wiping die member may be constructed as separate wiping die components, each of which may be adapted to turn at least a portion of the flange of the tray-shaped preform. Considering that the flange extends around the peripheral open edge of the rim, optionally, the wiping die member may be ring-shaped to surround the tray-shaped preform, such that movement of the wiping die member relative to the positioning die member effectively turns the flange protruding from the positioning die member in one movement. The wiping die member may also be generally rectangular. In this case, the wiping die member may surround the container, especially if the container has a generally rectangular cross section.

[0032] Because the side walls and / or end walls are connected to the lower part of the storage container by connecting to the connecting surfaces formed by turning the flanges, it is important to have a maximum contact area between the connecting surfaces in the lower part of the storage container and the side walls and / or end walls of the upper part of the storage container, particularly at the corners of the storage container. One of the problems associated with turning flanges to define connecting surfaces for connecting to the side walls and / or end walls is that any deformation or wrinkling of the flanges prevents proper connection between the connecting surfaces and the side walls and / or end walls, particularly at the corners of the storage container. For example, flanges tend to wrinkling, particularly at corners, to mitigate any plastic flow of metal during flange turning. As a result, the maximum surface contact between the side walls and / or end walls and the connecting surfaces at the corners is limited by the wrinkling of the flange. To mitigate this wrinkling during the turning process, optionally, trimming the corners of the flush with a trim corner cutting die includes forming notches in the corners of the flanges. Notches of various shapes can be formed in the corners of the flanges. These include, but are not limited to, V-shaped, U-shaped, or semicircular. The depth of the notches is such that excess metal that flows at the corners during the flange turn is accommodated by the space occupied by the notches, resulting in a smoother contact surface, thereby maximizing the surface contact between the flange and the top, i.e., side and end walls, of the storage container.

[0033] Optionally, the method further comprises stamping a step into the flange. Forming the step in the flange provides a seat in the flange for supporting edges of the side and end walls of the top of the storage container when the side and end walls are brought up to the connecting surface. Moreover, the step in the flange allows the side and end walls in the top of the storage container to be angled outwardly relative to the raised rim of the container. This has the effect of forming a storage container with outwardly tapered or sloped side and end walls. After forming the container with the required leakage capacity, the storage container is formed by attaching the side and end walls to the flange via their connecting surfaces. Optionally, the side and end walls are attached to the connecting surface by welding.

[0034] Optionally, the side walls are connected by their respective edges to the end walls to form corners of the storage container. Specifically, opposite edges of each of the side walls are connected to opposite edges of the respective end walls. When one or more of the storage containers are stored in one or more stacks in the grid framework structure, it is essential that each of the storage containers has sufficient structural integrity to withstand the weight of one or more of the storage containers in a given stack. For example, a given stack stored in the grid framework structure may be as tall as 20 storage containers. Considering that each storage container can weigh up to 35 kg, this amounts to a total weight of 700 kg. Without the necessary structural integrity in the walls of a storage container, there is a risk that the walls will collapse under the weight of one or more storage containers above them in the stack. The prior art, i.e., WO 2022 / 161863 (Autostore Technology AS), alleviates this problem by providing four separate corner posts interconnecting adjacent sides of the storage container. Although the provision of corner posts provides a storage container with sufficient structural integrity to withstand the weight of one or more storage containers in a stack, the interconnections between the corner posts and sides of the storage container are not suitable for providing a leak-proof storage container. This is because, in order for the storage container taught in WO 2022 / 161863 (Autostore Technology AS) to be leak-proof, it is important that the interconnections between the corner posts and sides of the storage container be leak-proof. However, complications arise when attempting to make connections between separate components leak-proof, as this is highly dependent on the type of connection used.

[0035] To eliminate the need for separate corner posts to interconnect the sides of the storage container, optionally, each of the side walls and end walls includes a connecting flange configured to overlap at the corners of the storage container when each of the side walls is connected to its respective end wall. Overlapping portions of the side walls and end walls at the corners of the storage container reinforces the corners of the storage container without the need for separate corner posts. The double skin formed from the connecting flanges at the corners of the storage container provides the corners of the storage container with sufficient structural rigidity to provide a load-bearing structure. Having connecting flanges on opposite ends or edges of the side walls and end walls of the storage container reinforces the storage container at its four corners. The connecting flanges may be integrally formed during stamping of the side walls and end walls from one or more separate sheet metal blanks. To further increase the structural rigidity of the storage container, optionally, the top of the storage container further comprises side wall and / or end wall rim portions, each of the side wall rim portions configured to fit to a respective side wall and / or each of the end wall rim portions configured to fit to a respective end wall. To further increase the structural rigidity of the storage container, particularly at the corners of the storage container, optionally, each of the end wall rim portions comprises a downwardly extending rim flange, each of the downwardly extending rim flanges configured to overlie a connecting flange of a respective end wall when the end wall rim portion is fitted to the end wall. The downwardly extending rim flanges overlie the connecting flanges at the corners of the storage container increase the structural rigidity of the storage container by increasing the number of sheet metal "skins" at the corners of the storage container from a double skin to a triple skin.

[0036] To enable the storage container to engage a grabber device of a load handling device, optionally the storage container is adapted to be lifted by an end wall and / or a side wall of the storage container. Optionally, each of the side wall and / or end wall comprises one or more openings or recesses for engaging a grabber device of a load handling device.

[0037] Tray-shaped preforms are stamped or drawn from sheet metal blanks comprising galvanized steel to plastically deform the sheet metal blank when drawn into a forming die. Galvanized steel is more ductile and easier to work than alternative corrosion-resistant steels, such as stainless steel. Stainless steel is stronger and more corrosion-resistant than galvanized steel, but suffers from lower ductility compared to galvanized steel.

[0038] To increase food safety using galvanized steel, the storage container may be lined with a food-safe compliant liner. In this case, the storage container is formed as a liner-lined metal container body. Optionally, the storage container comprises a liner formed from a food-grade material. Optionally, the liner comprises a food-grade plastic material and / or a cellulosic material.

[0039] The present invention provides a storage container for storing one or more items in a storage and retrieval system comprising a track system having 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 rails or tracks in a substantially horizontal plane to form a grid pattern comprising a plurality of grid spaces or grid cells and a plurality of stacks of storage containers positioned below the track system, wherein each stack of the plurality of stacks of storage containers occupies a single grid space or grid cell, and the storage container comprises a metal container body formed by the method described in the present invention.

[0040] The present invention provides a storage and retrieval system, comprising: i) a grid framework structure comprising a plurality of storage columns for storing one or more stacks of storage containers and a track system comprising a plurality of tracks arranged in a grid pattern comprising a plurality of grid cells, wherein the track system is disposed above the plurality of storage columns such that each of the plurality of storage columns is disposed below a respective grid cell of the track system; ii) one or more stacks of storage containers, wherein at least one of the storage containers in the one or more stacks of storage containers is formed by a method described in the present invention; iii) a plurality of load handling devices for lifting and moving the storage containers stacked in one or more stacks; a plurality of load handling devices remotely operated to move laterally on a track system 106 above the storage columns to access storage containers through the grid cells, each of the plurality of load handling devices comprising: a) a wheel assembly for guiding a load handling device on a track system; b) a container receiving space located above the track system; c) a lifting device configured to lift the storage container from the stack into the container receiving space; There is further provided a storage and retrieval system comprising:

[0041] Further features and aspects of the present invention will become apparent from the following detailed description of illustrative embodiments which proceeds with reference to the drawings. [Brief explanation of the drawings]

[0042] [Figure 1] 1 is an illustration of an automated storage and retrieval system according to an exemplary embodiment of the present invention. [Figure 2] 2 is a schematic diagram of a top view showing a stack of containers arranged within the framework structure of FIG. 1. [Figure 3]1 is a schematic diagram of a system of known cargo handling devices operating on a grid framework structure; [Figure 4] 1 is a schematic perspective view of a load handling device showing a container receiving space within the body of the load handling device; FIG. [Figure 5] 5 is a schematic perspective cutaway view of the load handling device of FIG. 4 showing (a) a container accommodating the container receiving space of the load handling device, and (b) the container receiving space of the load handling device. [Figure 6] FIG. 1 is a schematic perspective view of a grabber device positioned above a storage container. [Figure 7] FIG. 1(a) is a schematic perspective view of a grabber device mounted on a storage container, and FIG. 1(b) is a schematic perspective view of a grabber device engaging with a storage container. [Figure 8] 1 is a schematic perspective view of a storage container including a container base drawn from a sheet metal blank, in accordance with an embodiment of the present invention; [Figure 9] FIG. 9 is an exploded view of the storage container shown in FIG. 8. [Figure 10] 9 is a schematic perspective view of a side wall of the storage container shown in FIG. 8 formed from a sheet metal blank. [Figure 11] FIG. 9 is a schematic perspective view of the end wall shown in FIG. 8 formed from a sheet metal blank. [Figure 12] FIG. 9 is a schematic perspective view of a rim portion of the storage container shown in FIG. 8. [Figure 13] FIG. 9 is a perspective close-up view of a corner of the storage container shown in FIG. 8 showing double skin reinforcement from overlapping side wall and end wall flanges. [Figure 14] 1A is a schematic perspective view of (a) a rim portion of a storage container according to another embodiment of the present invention, the rim portion including downwardly extending rim flanges at opposite ends of the rim portion, and (b) an end wall including flanges at opposite ends of the end wall configured to overlie the downwardly extending flanges when the rim portion is installed on the end wall. [Figure 15]15(a) and 15(b) are schematic perspective cross-sectional views of a corner of a storage container assembled from the rim portion and end walls shown in FIGS. 14(a) and 14(b) and reinforced with three skins of sheet metal. [Figure 16] 1A-1C are schematic perspective views of steps in a manufacturing process illustrating drawing a single sheet metal blank into a drawing die to form a leakproof container according to an example of the present invention. [Figure 17] FIG. 17 is a schematic perspective view of a tray-shaped preform formed by drawing a sheet metal blank into the drawing die shown in FIG. 16. [Figure 18] 10A-10C are schematic perspective views of steps in a manufacturing process illustrating turning a flange with a wiping die, according to an example of the present invention. [Figure 19] 19A-19C are schematic perspective views of steps in a manufacturing process illustrating a flange turned by the wiping die shown in FIG. 18, according to an example of the present invention. [Figure 20] 10A-10C are schematic perspective views of steps in a manufacturing process illustrating trimming the flash of a tray-shaped preform in a trim cutting die to form a flange. [Figure 21] 10 is a schematic perspective view of a step in a manufacturing process illustrating trimming corner portions of a flash of a tray-shaped preform in a trim corner cutting die. FIG. [Figure 22(ab)] 22A and 22B are schematic perspective views of (a) a tray-shaped preform having a flange trimmed from the step shown in Figures 20 and 21 extending outward in a direction substantially perpendicular to the raised rim, and (b) a container that has been turned so that the trimmed flange of the tray-shaped preform extends in the same direction as the raised rim. [Figure 22(c)] FIG. 1 is a close-up view of a corner of a tray-shaped preform showing the radius of curvature R of the corner. [Figure 22(de)] Schematic diagram of (d) a flange at a corner of a tray-shaped preform without notches, and (e) a flange at a corner of a tray-shaped preform with notches. [Figure 23] 10A-10C are schematic perspective views of steps in a manufacturing process illustrating turning a flange of a tray-shaped preform by a wiping die. [Figure 24] 1 is a schematic perspective view of steps in a manufacturing process illustrating the steps of drawing a single sheet metal blank into a drawing die, turning a flange, and trimming a flash in a single operation. FIG. [Figure 25] 1 is a schematic perspective view illustrating an assembly line including assembly stations for assembling storage containers according to an example of the present invention; [Figure 26] 1 is a flowchart illustrating steps in assembling a storage container, according to an example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0043] The present invention addresses known features of storage systems, such as the grid framework structure and cargo handling device described above with reference to Figures 1-7(a and b). Figures 6 and 7(a and b) are examples of typical storage containers for use in storing items or goods in a grid framework structure. The storage containers are generally cubic, although storage containers of other shapes are applicable to the present invention. The storage containers shown in certain embodiments of the present invention have a generally rectangular cross-section. However, the present invention is not limited to having a rectangular cross-sectional shape, and other cross-sectional shapes, such as a square, are also applicable to the present invention. In order to be stored in a grid framework, the storage container should have the following characteristics:

[0044] A. Have sufficient structural integrity to allow the storage container to be stacked in storage columns in a grid framework structure without any of its walls deforming or changing shape.

[0045] B. The weight of the storage container is light in the sense that ideally it should be a small percentage of the weight of the contents of the storage container. Typically, storage containers in the art weigh about 5 kg to 8 kg. This prevents the lifting mechanism, including the lifting motor, from being overwhelmed by the weight of the storage container, and also allows heavier contents to be stored in the storage container.

[0046] C. It is leak-proof to prevent fluids, as a result of spills from items stored in the storage container, particularly food items, from escaping the storage container and contaminating the contents of other nearby storage containers.

[0047] D. Have relatively sharp corners or corners with small radii so that the storage containers in the stack can be stacked on top of each other in the storage column without any two of them getting stuck. Thus, storage containers should be equipped with corners that ensure separation of the storage containers when lifted by a load handling device operable on the grid framework structure.

[0048] E. The storage container material is fire resistant in the sense that it will not combust spontaneously and / or emit toxic fumes in the event of a fire.

[0049] Typically, the physical characteristics described above in items A-D are addressed by fabricating storage containers from thermoplastic materials because such materials are lightweight and can be molded into complex shapes. Examples of fabrication methods include, but are not limited to, injection molding, blow molding, and the like. As a result, storage containers can be molded with sharp corners, thereby allowing them to be stacked without getting stuck, especially when the storage containers support a stack of up to 21 storage containers, each with a total weight of approximately 35 kg. One common problem with not having sharp corners or corners with a tight radius is the risk of one or more corners of a storage container in a stack falling into the mouth 58 of an adjacent storage container below in the stack (see FIG. 6 ). This has the detrimental effect of causing any two storage containers to get stuck in the stack, thereby preventing the storage containers from being separated when attempting to lift one of the storage containers from the stack. In the worst case scenario, a load handling device operable on the grid framework structure is either prevented from lifting a storage container from the stack due to a corner jamming the vertical upright of the grid framework structure, or is forced to lift multiple storage containers in a single lift due to the storage containers getting stuck together. The problem of any two storage containers getting stuck together is exacerbated when the load handling device's grabber device fails to lower the storage container straight onto a storage container in the stack. This may be the result of any one of the lifting tethers connected to the grabber device used to engage the storage containers being of unequal length, causing the grabber device to tilt or tip as it is lowered and / or causing the storage container to swing as it is lowered down the storage column.To mitigate the possibility of any two storage containers becoming stuck due to being improperly seated on the adjacent storage container below them in the stack, it is essential that the storage containers be formed with tight corners, ideally 90° corners, to allow the storage container to rest squarely on the rim of the adjacent storage container below it in the stack. The ability to mold complex shapes from thermoplastic materials allows storage containers to be formed with complex shapes, particularly tight corners such as those shown in Figures 6 and 7(a and b). Other advantages of using thermoplastic materials when making storage containers for use in grid framework structures are the lightness of the material due to its inherent low density and its inherent leak-proof nature. The low density of thermoplastic materials allows the walls of storage containers to be made thick enough to provide the structural integrity necessary for stacking in a grid framework structure. The inherent leak-proof properties of thermoplastic materials mean that storage containers molded from thermoplastic materials will be leak-proof.

[0050] To allow air to flow through the storage containers 10 when held in a stack, the side walls 52(a and b) and / or end walls 54(a and b) of the storage containers 10 include one or more slots, openings, or vents 56. The slots or openings 56 in the side walls 52(a and b) and / or end walls 54(a and b) allow air circulating in and through the storage and retrieval system to flow through the storage containers 10. This is particularly important when the storage containers 10 are located in a cooling zone of a storage and retrieval system, where cool air from a refrigeration or air conditioning unit is circulated through at least a portion of a grid framework structure to keep items, such as grocery items, at a cool temperature. Cooling systems such as those described in International Patent Publication No. WO 2016 / 193419 (Ocado Innovation Limited) require air to flow through the storage system and through the storage containers 10 and stacks 12 of containers 10. The system described in this International Patent Application, which is incorporated herein by reference, discloses a storage system comprising one or more heaters and / or one or more chillers 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. For example, if a portion of the storage and retrieval system needs to be cooled to a lower temperature to allow for the storage of items that require cooling, such as fruits and vegetables, it is more important that the airflow through the system cools the items to be stored. It will be appreciated that in addition to cooling the storage system, items stored in the storage system can be heated in a similar manner using the same methods described.

[0051] One of the important characteristics of a storage container when storing food items is preventing leakage of food items from escaping the storage container and contaminating other food items stored in adjacent storage containers in a stack. Because fluids tend to pool at the base of a storage container, the storage container may be divided to have a lower or base portion 60 and an upper portion 62. Ideally, the lower or base portion 60 of storage container 10 is leakproof to prevent leakage of liquid trapped in the lower portion of the storage container from escaping the storage container, while the upper portion 62 provides side and end walls for containing goods within the storage container. Accordingly, optional vent holes 56 for the passage of air in the side and end walls are formed in the upper portion of the storage container to prevent fluid trapped in the lower portion of the storage container from escaping through the vent holes. The general consensus in the industry is to create storage containers with a capacity to capture approximately 20 to 30 liters of liquid without leakage (hereinafter referred to as the leak capacity or leakproof capacity). For example, for a storage container having dimensions of 448mm x 648mm x 362mm, this corresponds to the bottom of the storage container having a depth in the range of 90mm to 95mm.

[0052] While constructing storage containers from thermoplastic materials has the significant advantages discussed above, a problem with using thermoplastic materials is the potential for the materials to thermally burn and release toxic fumes in the event of a fire. The flammability of thermoplastic materials is such that a fire in a localized area of ​​the grid framework can rapidly spread to other areas of the grid framework structure due to the flammability of the storage containers. For example, if a fire breaks out in a localized area of ​​the grid framework structure, the excessive heat could melt one or more storage containers, causing the molten plastic to drip onto other areas of the grid framework structure. Given that there are multiple stacks of storage containers in a typical grid framework structure, a fire that breaks out in one area of ​​the grid framework structure could potentially cause a chain reaction as the fire spreads to other portions of the grid framework structure. The inherent flammability of thermoplastic materials means that alternative flame-resistant materials must be used in constructing the storage containers, while still possessing the required physical properties described in sections A through D above.

[0053] The material of choice for fabricating storage containers according to the present invention is metal because of its flame-resistant properties. However, storage containers according to the present invention are not limited to being formed entirely from a metal container body; at least a portion of the storage container can comprise other materials, such as plastic materials. Storage containers comprising a metal container body are also applicable to shipping containers, in the sense that shipping containers (DTs) can also comprise the metal container body of the present invention, comprising a container bottom wall, opposing side walls, and opposing end walls. In the following description, storage container 10 will be used to refer to a storage container intended for storing inventory items, while shipping container (DT) will be used to refer to a container that has been packed or is intended to be packed according to an order placed by a customer. It will be recognized that this terminology is used for ease of reference and description within this document. However, it should be noted that storage container 10 and DT can be of the same shape, size, and / or configuration. Furthermore, DTs can be stored in storage container 10 within a storage system or any part thereof. To allow access to the shipping container when nested in the storage container, the opposing side walls and / or opposing end walls of the storage container may be provided with cutouts 59 such that when combined with the shipping container, the cutouts 59 extend below the height of the shipping container.

[0054] In the examples of different types of storage containers discussed below with reference to Figures 8 and 9, the entire body of the storage container is formed from metal, in the sense that the metal container body of the storage container is defined as the storage container. This does not distract from the fact that the storage container can be equipped with a liner. In the case of food items, the liner can be formed from a food-grade material, for example, a food-grade plastic material and / or a wax-impregnated cellulosic material (cardboard). For ease of explanation, the metal container body in the following examples may be referred to as a storage container. The metal container body of the present invention can have a shape similar to that of currently used storage containers for storing items in a grid framework structure, for example, a generally rectangular container bottom wall, opposing side walls, and end walls. The metal storage container can be used among conventional plastic storage containers in the storage and retrieval systems described above with reference to Figures 3 and 6 and 7(a and b). The flame-resistant behavior of the metal storage container can be used to form a flame-resistant barrier in the grid framework structure. For example, multiple stacks of metal storage containers can be arranged to form one or more fire-resistant barriers to at least partially surround multiple stacks of storage containers comprising plastic material, which can be used to contain any fire within the grid framework structure.

[0055] FIG. 8 is an example of a storage container 110 fabricated from one or more sheet metal blanks according to the present invention, and FIG. 9 is an exploded view of the storage container shown in FIG. 8 . Similar to storage containers 10 currently in use, storage containers 110 according to the present invention can also be disassembled to have a lower or base portion 160 and an upper portion 162. Compared to forming the entire storage container as a single, integral body having a lower portion and an upper portion, which is typical when storage containers are fabricated entirely from plastic materials, storage containers according to illustrative embodiments of the present invention are assembled from separate lower and upper portions 160, 162. In the particular embodiment shown in FIG. 9 , the walls in the upper portion of the metal container body are formed as separate pieces, for example, by stamping or drawing from multiple sheet metal blanks, and then fixedly connected together to form upper side walls 164 and upper end walls 166. For purposes of definition, the term “upper side walls” can be referred to as the “side walls” of the storage container, and the term “upper end walls” can be referred to as the “end walls.” The upper side wall 164 and / or the upper end wall 166 may include one or more cutouts as shown in FIG. 6 to allow access to a shipping container (DT) nested within the storage container.

[0056] One or more separate rim portions 168 are mounted to the upper edges of the upper sidewall 164 and upper end wall 166 to define the rim of the metal container body 110. A separate rim portion 168 is mounted to each of the upper sidewall 164 and / or upper end wall 166. As shown in Figure 12, the rim portions 168 include one or more openings or recesses 149 for engaging a grabber device of a cargo handling device.

[0057] The upper sidewall 164 and upper end wall 166 of the metal container body 110 are each formed from a sheet metal blank, optionally by stamping or drawing the sheet metal blank (see FIGS. 10 and 11 ). The rim portion 168 may similarly be formed by stamping the sheet metal blank. The upper edge of the rim portion 168 is turned inward to form a lip 148 having one or more apertures or openings 149 for engaging a grabber device of a load handling device. The rim portions 168 are configured so that they clip or snap onto the exterior of the upper sidewall 164 and / or upper end wall 166. To improve the structural integrity of the box-like structure of the metal container body and enable the upper sidewall and upper end wall to be secured together, one or more connecting flanges 150, 152 are formed on opposite ends of the upper sidewall 164 and upper end wall 166. The flanges 152 of the upper end wall 166 are configured to overlap the adjacent connecting flanges 150 of the upper side wall 164 when the upper side wall 164 and the upper end wall 166 are joined with the lower portion 160 of the metal container body 110 to form a box-like structure. For example, the connecting flanges 152 of the upper end wall 166 are configured to overlap the adjacent connecting flanges 150 from the upper side wall 164. This is clearly shown in FIG. 13 . Each of the adjacent upper side wall or end wall flanges 150, 152 extends across a corner of the metal container body 110 to reinforce the corner. Various fasteners known in the art can be used to secure the upper side wall 164 and the upper end wall 166 together at the corners of the metal container body using their respective flanges. These include, but are not limited to, welding, e.g., spot welding, riveting, and / or the use of adhesives. In certain embodiments of the present invention, the connecting flanges 150, 152 of the upper side wall 164 and upper end wall 166 are fastened or connected together by a process called mechanical clinching. Clinching is similar to riveting, but does not require separate rivets and involves plastically deforming the sheet metal through the use of a special punch and die to create a physical interlock between the sheet metal layers.To further enhance the structural integrity of the box-like structure, the rim portion 268 mounted on the upper end wall 166 may optionally include a rim flange 254 at each corner that overlies each connecting flange 152 of the upper end wall 166.

[0058] To enable the gripper elements of the grabber device to be properly aligned with the apertures or openings 149 in the rim portion of the storage container, the metal container body includes guides 144 at each corner of the box-like structure of the metal container body 110, extending vertically from the upper edge or rim of the storage container at least partially along the height of the box-like structure of the storage container for receiving guide or locating pins of the grabber device. As discussed above with reference to FIG. 6 , the guides 144 are shaped to cooperate with the guide or locating pins of the grabber device to properly align the gripper elements 46 with the openings 149 in the rim portion 168 of the storage container. The guides 144 at the corners of the metal container body are formed by elongated vertical recesses in the connecting flanges 150, 152 of the upper sidewalls and / or upper end walls 164, 166. The elongated vertical recesses 144 may be formed by one or more bends in the sheet metal of the upper sidewalls 164 and / or upper end walls 166. In a specific embodiment of the present invention, an elongated vertical recess 144 is formed in the connecting flange 152 of the upper end wall 166, as shown in FIG. 11. The elongated vertical recess 144 in the connecting flange 152 of the upper end wall 166 is configured to overlap the connecting flange 150 of the upper side wall 164 at a corner of the box-like structure of the metal container body 110 when the upper side wall 164 and upper end wall 166 are brought together, as shown in FIG. 13. The overlapping connecting flanges 150, 152 of the upper side wall 164 and upper end wall 166 provide a corner of the metal container body 110 comprising two overlapping layers. This in turn reinforces the corner of the metal container body 110 to withstand loads from one or more storage containers positioned above, particularly when the storage container comprising the metal container body is placed in a stack of storage containers. Thus, from the two-part corner structure shown in FIG. 13, rigidity exists through the corner of the metal storage container 110.

[0059] To further reinforce the corners of the storage container, a rim portion 268 mounted on the upper end wall 166 can optionally include a downwardly extending rim flange 254 at each corner that overlaps the respective connecting flange 152 of the upper end wall 166. Thus, instead of having a double skin of the metal container body at the corners of the storage container, the overlapping connecting flanges 150, 152 of the upper side wall 164 and upper end wall 166, together with the overlapping flanges 254 of the rim portion 268, provide three overlapping layers at the corners of the metal container body 110. This is best seen in Figures 14(a and b), where Figure 14(a) shows a rim portion with a downwardly extending rim portion 254 configured to cooperate with opposing flanges of the end walls in the top of the storage container to increase the number of skins at the corners of the storage container from two skins, as shown in Figure 13, to three skins. Similar to the storage containers discussed above, the opposing side walls 164 and end walls 166 of the storage container 110 may include one or more slots, openings, or holes 149 to allow engagement with the gripper elements of a grabber device. To accommodate guides for the locating pins 42 of the grabber device, the downwardly extending flange 254 and the flange 152 of the upper end wall 166 include cooperating vertical recesses 244a, 244b that overlap to form guides for the locating pins 42 when the rim portion 268 is assembled onto the end wall 166, as shown in Figures 14(a and 14(b)).

[0060] To increase the structural rigidity of a storage container, one or more walls of the storage container may be embossed with one or more ribs 112. In a specific embodiment of the invention shown in Figures 8 and 9, the bottom and top walls of the storage container are embossed with a plurality of ribs 112 to strengthen their respective walls. The orientation of the ribs depends on the direction of the load applied to the storage container walls. When the storage container walls are loaded in a substantially vertical direction while supporting one or more storage containers in a stack, the plurality of ribs 112 embossed in the side and end walls of the storage container extend in a substantially vertical direction (see Figures 8-11).

[0061] A challenge with assembling storage container walls from multiple stamped sheet metal blanks is ensuring there are no leaks at the joints or interfaces between adjacent walls of the storage container. In the present invention, the lower portion 160 is formed by drawing or stamping a single sheet metal blank to form a container (tray-shaped preform) or tray 170 comprising a container bottom wall 172 and upwardly upstanding, opposing base side walls 174 and end walls 176 (see FIG. 22 ). To distinguish them from the opposing side walls 164 and end walls 166 in the upper portion 162 of the storage container, the upwardly upstanding, opposing base side walls 174 and end walls 176 of the lower portion of the storage container may be defined as a raised rim 180. The raised rim comprises the base side wall 174 and base end wall 176 of the container. The side walls 164 and end walls 166 in the upper portion of the storage container are assembled with the lower portion to form a box-like structure according to an exemplary embodiment of the present invention. Compared to the upper portion of the storage container, it is important that the lower portion of the storage container be leak-proof when storing grocery items. To fabricate the lower portion as a leak-proof container, the lower portion is ideally formed from a single sheet metal blank that is plastically deformed to form a tray-shaped preform 178 as shown in FIG. 17. The tray-shaped preform is shown in FIG. 17 with a raised rim 180 and a flange 182 extending outwardly around the peripheral open edge of the raised rim 180. For purposes of definition, the raised rim 180 of the tray-shaped preform comprises opposing upwardly upstanding base sidewalls 174 and end walls 176 of the lower portion 160 of the storage container 110. The flange 182 is formed as a result of a stamping or drawing process, as described further below.

[0062] According to an exemplary embodiment of the present invention, the lower portion 160 of the storage container is formed by stamping or drawing a single sheet metal blank 185 in a single operation through a forming or drawing die 184, involving stretching the sheet metal blank by the mechanical action of the forming or drawing die into the sheet metal blank. As shown in FIG. 16 , the drawing die 184 includes a retaining die member 186, an upper die member 188 having a die cavity 190, and a lower die member 189 including a punch 192. The holding or clamping force of the retaining die member 186 is controlled by controlling the pressure of gas applied to the pad 186. The punch 192 can be located on a die platen or die member (not shown). However, the present invention is not limited to the upper die member 188 including the die cavity 190 and the lower die member 189 including the punch 192, but is also applicable to the case where the lower die member 189 includes the die cavity 190 and the upper die member 188 includes the punch 192, or vice versa. The operation of the drawing process involves bringing upper and lower die members 188, 189 together so that punch 192 forces sheet metal blank 185 into die cavity 190 to form tray-shaped preform 178 as shown in Figure 17. During the drawing step, punch 192 cooperates with die cavity 190 to draw the ends of the sheet metal blank inwardly in the direction of the arrows. Peripheral stresses created during the drawing process make flange 182 a critical area of ​​tray-shaped preform 178.

[0063] To prevent wrinkling of flange 182 and control the drawing process, retaining die member 186 applies pressure to flange 182 to inhibit wrinkling and control the drawing process of the sheet metal into die cavity 190. Retaining die member 186 can function independently of punch 192, so retaining die member 186 secures the periphery of blank 185 to control the amount of blank material drawn into die cavity 190. Tray-shaped preform 178 is an intermediate step in creating the lower portion of the storage container. In all of the above cases, the sheet metal blank is drawn by a single drawing process. During the drawing process, sheet metal blank 185 undergoes superplastic deformation as the sheet metal is drawn into die cavity 190. The degree of plastic deformation varies throughout tray-shaped preform 178 and is greatest at corners 194 of tray-shaped preform 178. This is illustrated by the irregular shape of the flanges 182 at the corners 194 of the tray-shaped preform 178, because these areas of the flanges 182 experience excessive stretching of the sheet metal 185 when clamped into the holding die members (or blank holders) 186. For purposes of definition herein, the areas of the sheet metal blank clamped into the holding die members during the drawing process may be referred to as flash 196, and represent the areas of the sheet metal blank extending outward around the peripheral open edge of the rim of the tray-shaped preform 178; i.e., the flash 196 extends outward in a direction substantially perpendicular to the walls of the tray-shaped preform. The flash 196 comprises excess material attached to the container 170. To convert the tray-shaped preform 178 into the container 170 (as shown in FIG. 22b) that forms the lower portion 160 of the storage container 110, the flash 196 is typically removed, for example, by trimming.

[0064] However, drawing or stamping the container 170 from a single sheet metal blank 185 to form a container 170 with the correct depth to provide the required leakage capacity relies heavily on the metal's ability to plastically deform to conform to the shape of the die cavity without fracture or localized thinning, i.e., the metal's tensile strength. This is because stamping or drawing a sheet metal blank utilizes the metal's superplasticity, or its ability to be strained beyond its breaking point at a given operating temperature. The more ductile the metal, the greater its ability to plastically deform to the shape of the die cavity. Not only must the metal be sufficiently ductile to be able to plastically deform to the shape of the die cavity, but the metal must also be sufficiently corrosion-resistant to hold food items. An example of a metal type used in the industry to hold food items is stainless steel. However, stainless steel is less easily machined than other corrosion-resistant steels, such as galvanized steel. Generally, galvanized steel is more ductile and easier to process than stainless steel because the inner core of the galvanized steel may be selected from a variety of ductile steels or irons, and the zinc coating protects the steel or iron underneath from corrosion. In a specific example of the present invention, the metal type in the formation of the lower portion 160 of the storage container comprises galvanized steel due to its ability to be easily processed. In a specific embodiment of the present invention shown in Figures 18, 19, and 22(a and b), the container in the lower portion 160 is formed as a shallow container having a depth that is less than the length and width of the container. In a specific embodiment of the present invention, the container is formed as a shallow container 170 having dimensions of 448 mm (length) x 648 mm (width) x 93 mm (height).

[0065] To increase food safety, the storage container 110 may be lined with a liner, as discussed above, that complies with food safety standards. However, the present invention is not limited to galvanized steel; other metal types that are corrosion resistant and have the necessary ductility to be plastically deformed into the lower portion of the storage container are applicable to the present invention. Optionally, the upper portion 162 of the storage container 110, e.g., the side walls and / or end walls, may be formed from a plurality of sheet metal blanks, each of which comprises galvanized steel.

[0066] Although galvanized steel has sufficient ductility to be drawn into container 170, the drawing process has limitations when cold-working a sheet metal blank because, at low temperatures, the ductility of the steel decreases to a degree that the leakage capacity, and therefore the depth, of the container formed by the drawing process cannot be achieved by simply drawing the sheet metal blank in a single process. The more complex the container shape, in this case, the narrower the angle at corner 194 of container 170, the greater the strain the sheet metal will experience as it is plastically deformed in the drawing process, to the point where it may reach a breaking point before it can be fully formed into the die cavity. This results in either localized thinning of the sheet metal, particularly around corner 194 of container 170, or tearing of the sheet metal. However, the narrower the angle at corner 194 of container 170, in the sense that the angle at the corner approaches 90°, the more likely storage containers formed from container 170 will be stackable without any two of the storage containers becoming stuck. According to the present disclosure, each of the corners of the container 170 has a radius R in the range of 5 mm to 10 mm, preferably in the range of 5 mm to 8 mm (see FIG. 22(c)). Considering that a typical grid framework structure can hold hundreds or thousands of storage containers, cold working a sheet metal blank would be the most cost-effective and efficient process for manufacturing the lower portion 160 of the storage container 110. However, the ductility limitations of the sheet metal blank when cold working it into a tray-shaped preform 178, and the preference for fewer drawing operations (preferably a single drawing operation) for drawing the sheet metal blank, mean that the leakage capacity, and hence depth, of shallow containers cannot be achieved by solely drawing a sheet metal blank into a tray-shaped preform.

[0067] According to the present invention, the leakage capacity of the container is increased by the additional process of turning the flange 182, which extends outward around the peripheral open edge of the raised rim 180, inward toward the mouth 200 of the tray-shaped preform 178, so that the inwardly turned flange 182 extends in the same direction as the container wall, i.e., forms part of the container wall. This is shown diagrammatically by the arrows in FIG. 18. This has the effect of increasing the container depth, and hence the leakage capacity, of the container 170, without having to increase the depth solely through the mechanical action of the drawing process. The container depth, and hence the leakage capacity, can be controlled by controlling the width D of the flange 182 (see FIG. 22a). The greater the width of the flange 182, the greater the container depth, and vice versa. In the particular example of the present invention shown in FIG. 22a, the flange has a width D of approximately 20 mm, and the height of the raised rim 180 is approximately 75 mm. This gives an overall height of 95 mm when the flange is turned, thereby increasing the leakage capacity.

[0068] A wiping die or wiping edge bending die 198, as known in the art, can be used to turn the flange 182 inward so that the flange 182 lies in a vertical plane, as shown schematically in FIGS. 18 and 19 . The tray-shaped preform 178 is positioned in the wiping die 198 so that the flange 182 extends across the wiping die 198. The wiping die 198 is moved relative to the tray-shaped preform 178 toward the flange 182 so that the flange extending across the wiping die is bent in an inward direction as the wiping die advances over the flange. Bending the flange inward by the wiping die is shown schematically in the drawings of FIGS. 18 and 19 , which show the wiping die 198 moving in an upward direction indicated by an arrow relative to the tray-shaped preform 178. In the particular embodiment of the invention shown in FIGS. 18 and 19 , the wiping die 198 is formed as a ring-shaped tool to surround the walls 174, 176 of the container 170. This has the resulting effect of turning the flange 182 toward the container mouth 200 in a single motion so that the flange lies in a substantially vertical plane. For purposes of the present invention, the term "turning inward" encompasses bending or erecting the flange at the joint or connection between the flange and the container wall 174, 176, i.e., at the rim of the tray-shaped preform, as indicated by the curved arrow in FIG. 18 . The use of a ring-shaped wiping die 198 allows the flange 182 to be turned with a single motion of the wiping die. The resulting container 170 has a raised flange 182 that increases the depth of the container 170, as shown in FIG. 22b. The turned flange 182 also defines a connecting surface for attaching the top of a storage container comprising the side walls 164 and end walls 166.

[0069] Cold working complex shapes, particularly narrow or small radius corners, into a single sheet metal blank can only be achieved up to a certain depth in the tray-shaped preform before the metal's break point is reached, beyond which the sheet metal will begin to fracture. The two-step operation of stamping or drawing the sheet metal blank into the tray-shaped preform 178 and subsequently erecting or inwardly turning the flanges 182 to define the container 170 with an increased height allows complex shapes, particularly narrow or small radius corners, with a predefined depth or leakage capacity to be formed in the sheet metal blank by cold working alone. As a result, the depth, and hence the leakage capacity, of the resulting shallow container can be controlled by the flange width D and shape. The resulting effect of the two-step operation on a tray-shaped preform to form a container is illustrated in Figures 22(a) and 22(b). Figure 22a is an example of a tray-shaped preform before the flanges are turned or erected inward, and Figure 22b shows the container being formed by turning or erecting the flanges so that they lie in a substantially vertical plane.

[0070] To control the depth of the container 170, the flange 182 is formed by trimming the flash 196 of the tray-shaped preform 178 to a predetermined width and / or shape. Once the stamping or drawing process is complete, the tray-shaped preform is removed from the drawing die and sent to a trim cutting die 201, shown in FIG. 20, to trim the flash and form the flange 182 with a predetermined width D. According to an example of the present invention, the stamping or drawing process produces a tray-shaped preform with a depth of approximately 70 mm. To provide a container with a depth of 93 mm, the flange has a predetermined width D of 20 mm. The depth of the tray-shaped preform is not limited to 70 mm and can be any depth within the limits of the stamping or drawing process that reach the breaking point of the sheet metal; for example, the depth can be 50 mm, 60 mm, 80 mm, 90 mm, or 100 mm. Similarly, the width of the flange is not limited to 20 mm and can be any width depending on the required depth of the final container, for example, the flange width can be 10 mm, 15 mm, 25 mm, or 30 mm. In certain embodiments of the present invention, the sheet metal blank is formed into a shallow container. However, the flange width D can be greater than the width and / or length of the preform so that when the flange is turned, the resulting container is formed as a deep container.

[0071] The trimming of the flash 196 is performed by holding the tray-shaped preform 178 between a pad 202 and a positioning die member 204, as shown in FIG. 20 , so that the flash 196 protrudes from the positioning die member 204 and the pad 202. The flash 196 is trimmed by sliding a trimming punch 206 over the face of the positioning die member 204 and the pad 202, as shown in FIG. 20 . The spacing between the trimming punch 206 and the faces of the positioning die member 204 and the pad 202 determines the width of the resulting flange 182. An optional forming operation may be included prior to the flash trimming operation discussed above with reference to FIG. 20 . As discussed above with reference to FIG. 17 , the flash 196 has an irregular shape due to excessive plastic deformation of the sheet metal in the blank holder near the corners of the tray-shaped preform 178.

[0072] In addition to trimming the flashing to a predetermined width as discussed above with reference to FIG. 20 , the flashing may be shaped by removing excess sheet metal around the corners of the flashing 196. Thus, once the stamping or drawing process is complete, the tray-shaped preform 178 may be removed from the drawing die and fed to the trim corner cutting die 208, as shown in FIG. 21 . Cutting the corners of the flashing 196 is performed by holding the tray-shaped preform between the pad 210 and the positioning die member 212 so that the flashing 196 protrudes from the positioning die member 212 and the pad 210. The corners of the flashing 196 are trimmed by sliding a trim cutting punch 214 over the face of the positioning die member 212 and the pad 210, as shown in FIG. 21 . The surface area of ​​the flange 182 provides a connecting surface 226 for attachment to side and / or end walls in the top of a storage container, as discussed further below. Maximum contact area is achieved by ensuring that there is essentially a substantially flat surface for attachment to the side and / or end walls in the upper portion of the storage container. Ideally, the height H of the connection surface 226 extending around the periphery of the container 170 is substantially equal to the width of the flange (see FIG. 22(b)). However, a problem with turning the flange 182 once trimmed is the risk that the flange will wrinkle, especially at the corners of the flange, resulting in an uneven surface, thereby limiting the maximum contact area when connecting to the side and / or end walls in the upper portion of the storage container. This is best illustrated by the schematic diagram of the corner 194 of the flange 182 shown in FIGS. 22(d) and 22(e). In FIG. 22(d), the corner 194 of the flange has a contour with an angle of approximately 90°. During the turning of the flange when increasing the depth of the container 170 in the lower portion of the storage container, the sheet metal experiences compression, as indicated by the dashed arrow in FIG. 22(d). Compression of the sheet metal at the flange corners is relieved by a combination of wrinkling of the sheet metal and plastic flow of the material. Notches 195 can be cut into the flange corners 194 to prevent wrinkling of the flange at the corners when the flange is turned or erected by the wiping die.The flow of material as a result of the compression of the metal when the flange is turned is thus accommodated by the notches 195 at the corners of the flange, as evidenced by Figure 22(e). The notches provide a space or area for the metal to flow as it is turned, thereby preventing wrinkling at the corners of the container. As the material flows outward during the turning of the flange, as shown by the dashed lines in Figure 22(e), the contour of the container at the corners can be restored such that the height H of the connection surface around the periphery of the container 170 or tray-shaped preform 178 is substantially uniform, as shown in Figures 22(b) and 22(c).

[0073] As discussed above with reference to Figures 18 and 19, a wiping or edge bending die 198 is used to turn or stand the flanges inward so that they lie in a substantially vertical plane. Once the flash 196 is trimmed to form the flanges 182 having a predetermined width, the trimmed tray-shaped preform is removed from the positioning die member of the trim cutting die 201 and sent to a wiping die 198, which includes a positioning die member 215 and a wiping die member 218, as shown in Figure 23, where the flanges 182 are bent inward to increase the depth of the tray-shaped preform. The wiping die bending is performed by supporting the sheet metal blank on the positioning die member 215 so that the flanges 182 protrude from the positioning die member 215. The turning or bending of the flanges 182 is performed by sliding the wiping die member 218 over the face of the positioning die member 215 to turn the protruding flanges inward, as shown in Figure 23. The reverse is also true, with the positioning die member 215 supporting the tray-shaped preform acting as a punch and being moved towards the wiping die member 218 to turn the flange 182 protruding from the positioning die member 215 .

[0074] Although separate dies are described above for different manufacturing steps of the container in the lower part of the storage container, one or more of the manufacturing steps of the lower part of the storage container 160 may be performed using the same tool or die. For example, one or more of the manufacturing steps of the lower part of the storage container may share the same tool or die. To share the same tool among multiple manufacturing steps of the lower part of the storage container, one or more of the dies may be integrated into the drawing die 184 but share the same positioning die member 192 to support the tray-shaped preform 178 while the stamping operation is being performed. The one or more dies may be a wiping die member 218 and / or a trim-cutting punch 206 and / or a corner-cutting die 208. In the particular embodiment of the invention shown in FIG. 24 , the wiping die member 218 and the trim-cutting punch 206 are integrated into the wiping die 184, i.e., into the wall of the upper die member 188 that comprises the die cavity 190. FIG. 24 is a schematic diagram of a section of a drawing die 184 incorporating a wiping die member 218 and a trim-off punch 206. Because the drawing die 184 is shared, the punch 192 of the drawing die 184 can function as a positioning die member to support the tray-shaped preform 178 during subsequent operations. This eliminates the need to feed the tray-shaped preform to another die when performing different stamping operations. A problem with repeatedly feeding the tray-shaped preform when performing different stamping operations is the need to repeatedly remove the tray-shaped preform from the positioning die member. Each time the tray-shaped preform is removed from the positioning die member, there is a risk of deforming the tray-shaped preform, thereby reducing the structural integrity of the tray-shaped preform, particularly the bottom wall of the tray-shaped preform. In certain embodiments of the present invention, the tray-shaped preform 178 formed from the drawing process remains on the punch 192 after the drawing operation. Once the wiping die member 218 is integrated into the drawing die 184 , the flange 182 is then turned by moving the upper die member 188 towards the punch 192 .This can be followed by trimming off any flash or excess sheet metal with a trimming punch 206 integrated into the die cavity 190. From this, the container 170 can be formed by a series of stamping operations of the punch 196 and / or upper die member 188, each stamping operation completing a different operation of the container. In either case, the tray-shaped preform 178 is held in the holding die member 186 of the drawing die 184.

[0075] In a particular embodiment of the invention, as shown in FIG. 23 , the wiping die member 218 is molded to include a step 222 in the flange in addition to turning the flange. This is clearly shown in the schematic representation of a shallow container shown in FIG. 22 b. As discussed above, the separate side wall portions 164 and end wall portions 166 of the storage container's top portion 162 are assembled with the bottom portion to form the box-like structure of the metal container body. Stamping the step 224 in conjunction with turning the flange inward provides a connecting surface 226 in the container for attaching the top portion to the bottom portion of the storage container. In addition to joining the side and end walls 164, 166 together via their respective connecting flanges 150, 152 in the storage container's top portion 162, as discussed above with reference to FIGS. 10 and 11 , the separate side and end walls 164, 166 are assembled onto the container by joining the side and end walls to the turned flanges via their respective connecting surfaces 226, as shown in FIGS. 8 and 9 . The turned flanges provide areas in the lower portion of the storage container for joining the side and end walls to the container. The side and end walls in the upper portion of the storage container may be formed with corresponding connecting or mating surfaces 228 for joining to the turned flanges in the lower portion of the storage container (see FIG. 10 ). The step 224 in the flange 182 also provides a surface for supporting the edges of the side and end walls 164 and 166 as they are brought to the lower portion of the storage container. Various fasteners may be used to join the side and end walls of the upper portion of the storage container to the inwardly turned flanges of the shallow container. These include, but are not limited to, welding, e.g., spot welding, riveting, and / or the use of adhesives. The side and end walls 164 and 166 may be angled outward relative to the raised rim 180 of the container so that the walls of the storage container taper outward.

[0076] Separately forming a container into a shallow container and then assembling side and end walls to the shallow container to form a storage container according to an exemplary embodiment of the present invention is suitable for automating the assembly of storage containers according to the present invention. FIG. 25 , in conjunction with FIG. 26 , may be used as an example of automating a manufacturing process 270 for a storage container according to the present invention. Various assembly stations may be used to assemble the different parts of the storage container discussed above. While not shown in FIG. 25 , the process begins with a drawing station for drawing or stamping the shallow container. This is shown as step 296 in the flowchart of FIG. 26 . The two-step operation of drawing a tray-shaped preform followed by the inward turning or bending of the flanges discussed above may be automated for mass production of multiple shallow containers 170 that form the bottom portion of the storage container. The formed shallow containers are fed into an assembly area 274, shown in FIG. 25 , which includes multiple assembly stations for assembling the side walls 164 and end walls 166 of the storage container to the shallow container 170. In the particular example of an automated process shown in FIG. 25 , shallow containers 170 are sequentially fed via conveyor system 276 to different assembly stations in assembly area 274. Robotic arms at the different assembly stations may be commanded to perform one or more tasks detailed in the flowchart shown in FIG. 26 when assembling a storage container in accordance with the present invention. As shown in FIG. 25 , first assembly station 278 includes a first robotic arm 280 commanded to assemble end wall 166 to shallow container 170 during a first preform stage of the storage container to form a preform storage container 282. This is shown as step 298 in FIG. 26 . At first assembly station 278, a second robotic arm 284 may be commanded to join the end wall to the shallow container, for example, by spot welding. This is shown as step 300 in FIG. 26 .Once the end wall 166 is joined to the shallow container 170, the preform storage container 282 is fed to a second assembly station 286, where a third robotic arm 288 can be instructed to assemble the side wall 164 to the end wall 166 and the shallow container 170. This is shown in FIG. 26 as step 302. The step of turning the flange 182 of the shallow container 170 to define the connecting surface 226 allows the walls (side and end walls) of the storage container to be easily assembled onto the shallow container 170. At the second assembly station 286, a fourth robotic arm 290 can be instructed to join the side wall 164 to the shallow container 170 via the connecting surface of the turned flange 182. This is shown in FIG. 25 as step 304. The first and second stations 278, 286 may share the same robotic arm for joining the end walls 166 and side walls 164, respectively, to the shallow container 170, or alternatively, the first and second stations 278, 286 may each include a separate robotic arm for joining the end walls 166 and side walls 164 to the shallow container 170. An additional third assembly station 292 including a fifth robotic arm 294 may be commanded to assemble the rim portion 168 to the side walls 164 and end walls 166 to complete the assembly of the storage container. This is shown in FIG. 26 as step 306.

[0077] Compared to plastic storage containers currently used to store goods, storage containers formed from assembling stamped or drawn sheet metal blanks not only meet the fire-resistant criteria set forth in item E above, but their leak-proof bottoms with narrow corners also meet the criteria set forth in items A through D above. The ability to form the container through a two-step process—stamping or drawing a single sheet metal blank to form a tray-shaped preform, followed by turning the flanges so that they extend in the same direction as the raised rim of the tray-shaped preform—provides the container with narrow corners for stacking in a storage column and the required leak capacity to a given depth. Having narrow corners meets the stackability criteria set forth in item D, and the increased depth of shallow containers meets the criteria set forth in item C, providing sufficient leak capacity to capture leaks without contaminating the contents of other storage containers in the stack. Another advantage of forming the bottom or base portion of a storage container separately from the top is that a different thickness of sheet metal can be used for the bottom than for the top, improving the structural integrity of the assembled storage container. For example, when forming a container (or shallow container), a thicker sheet metal blank may be used for the lower part of the storage container than for the upper part of the storage container. While the preferred metal type in fabricating the storage containers discussed above is galvanized steel, the present invention is not limited to fabricating storage containers from galvanized steel. The ability to increase the depth of the container in the lower part of the storage container by the two-step process discussed above allows other corrosion-resistant metal types, such as stainless steel, to be used in fabricating the storage container. Optionally, different corrosion-resistant metals may be used for the upper and lower parts of the storage container, for example, galvanized steel for the lower part of the storage container due to its formability and stainless steel for the upper part of the storage container.

[0078] Although preferred embodiments of the present invention have been described above in detail, it should be understood that various modifications of the storage container, including different features described above and different combinations of features described in connection with different embodiments, are applicable within the scope of the present invention as defined in the claims.

Claims

1. 1. A method of manufacturing storage containers for storage in a stack in a grid framework structure comprising a plurality of storage columns, each of the plurality of storage columns configured to store a stack of storage containers, the method comprising: A) i) stamping or drawing a sheet metal blank into a drawing die to form a tray-shaped preform having a base with a raised rim and flange; ii) turning the flange to define a connecting surface extending in the same direction as the raised rim of the tray-shaped preform to form a container having a predefined depth; forming a lower portion of the storage container by B) iii) stamping the side walls and / or end walls from one or more separate sheet metal blanks; forming a top portion of the storage container by C) attaching the lower portion to the upper portion by attaching the side and end walls to the connecting surfaces of the container; A method comprising:

2. 10. The method of claim 1, wherein the drawing die comprises a retaining die member, an upper die member, and a lower die member, at least one of the upper and lower die members comprising a punch and the opposing die member comprising a die cavity.

3. The method of claim 2 , further comprising using the retaining die member with the punch to control the amount of the sheet metal blank drawn into the die cavity.

4. The flange is turned by a wiping die having a positioning die member and a wiping die member, and the method comprises: i) holding the preform in the positioning die member so that the flange extends outwardly from the positioning die member; ii) moving the wiping die member relative to the positioning die member to turn the flange; The method of claim 2 or 3, further comprising:

5. The method of claim 4 , wherein the wiping die member is ring-shaped.

6. The method of claim 4 or 5, wherein the wiping die member is generally rectangular.

7. The method according to any one of claims 4 to 6, wherein the wiping die member is integrally formed with the drawing die.

8. 8. The method of claim 4, wherein the tray-shaped preform comprises a flash extending from a raised rim of the tray-shaped preform, the method further comprising the step of trimming the flash to form the flange by a trim-cutting die comprising a trim-cutting punch and a positioning die member for supporting the tray-shaped preform, the flash being trimmed by moving the trim-cutting punch relative to the positioning die to form the flange.

9. The method of claim 8 , wherein the trim cutting punch is integrally formed with the drawing die.

10. 10. The method according to claim 8 or 9, further comprising the step of trimming corners of the flashing with a trimming corner-cutting die comprising a corner-cutting punch and a positioning die member for supporting the tray-shaped preform, wherein the corners of the flashing are trimmed by moving the corner-cutting punch relative to the positioning die member.

11. The method of claim 10 , wherein trimming the corners of the flashing with a trim corner cutting die comprises forming notches in the corners of the flashing.

12. 12. The method of claim 10 or 11, wherein the corner cutting punch is integrally formed with the drawing die.

13. 13. A method according to any preceding claim, wherein the flange extends outwardly around a peripheral open edge of the raised rim, and the flange is turned by turning the flange inwardly so that it extends in the same direction as the raised rim of the tray-shaped preform.

14. The method of any one of claims 1 to 13, wherein the container in the lower portion of the storage container is a shallow container.

15. The method of any one of claims 1 to 14, further comprising stamping a step into the flange.

16. The method according to any one of the preceding claims, wherein the side walls and end walls are attached to the connecting surfaces by welding.

17. The method of any one of claims 1 to 16, wherein the side walls are connected by their respective edges to the end walls to form corners of the storage container.

18. 18. A method according to any preceding claim, wherein each of the side and / or end walls of the top of the storage container comprises one or more openings or recesses for engaging a grabber device of a load handling device.

19. A method according to any one of the preceding claims, wherein the tray-shaped preform is stamped or drawn from the sheet metal blank comprising galvanized steel.

20. 20. A storage container for storing one or more items in a 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 transverse to the first set of parallel rails or tracks in a substantially horizontal plane to form a grid pattern comprising a plurality of grid spaces or grid cells; and a plurality of stacks of storage containers positioned below the track system, wherein each stack of the plurality of stacks of storage containers occupies a single grid space or grid cell, and the storage container comprises a metallic container body formed by the method of any one of claims 1 to 19.

21. 21. The storage container of claim 20, wherein the storage container comprises a liner formed from a food-grade material.

22. 1. A storage and retrieval system comprising: i) a grid framework structure comprising a plurality of storage columns for storing one or more stacks of storage containers and a track system comprising a plurality of tracks arranged in a grid pattern comprising a plurality of grid cells, wherein the track system is disposed above the plurality of storage columns such that each of the plurality of storage columns is disposed below a respective grid cell of the track system; ii) one or more stacks of storage containers, wherein at least one of the storage containers in the one or more stacks of storage containers is formed by the method of any one of claims 1 to 19; iii) a plurality of cargo handling devices for lifting and moving the storage containers stacked in said one or more stacks; a plurality of the cargo handling devices are remotely operated to move laterally on the track system above the storage columns to access the storage containers through the grid cells, and each of the plurality of cargo handling devices comprises: a) a wheel assembly for guiding the load handling device on the track system; b) a container receiving space located above the track system; c) a lifting device configured to lift a storage container from the stack into said container receiving space; A storage and retrieval system comprising:

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