Grid framework structure

Abstract

The present invention relates to a grid framework structure (14) for supporting a load handling device (30) operated to move one or more containers, wherein the grid framework structure comprises a plurality of upright members (16) arranged to form a plurality of vertical positions for guiding one or more containers in a vertical direction by upright members, wherein the plurality of upright members (16) are interconnected to define nodes at normal ends by a plurality of grid members (18, 20) arranged in a grid pattern including a first set of grid members extending in a first direction and a second set of grid members extending in a second direction, wherein the second set of grid members is transverse to the first set of grid members in a substantially horizontal plane to form a grid structure (14b) comprising a plurality of grid cells, and the grid structure (14b) comprises a track system positioned on the plurality of grid members, wherein the track system comprises a plurality of tracks arranged in a grid pattern, and the plurality of upright members comprises a first upright member and a second upright member, and the upright members are a At least one of a plurality of grid members extending between a first upright member and a second upright member is interconnected, and the first upright member is interconnected by at least one of the plurality of grid members by a connecting portion (130, 158) including a pivotable joint at its normal end, so that when one of the first or second upright members moves relative to the other of the first or second upright members, at least one of the plurality of grid members can rotate in a horizontal plane about a vertical axis extending through the pivotable joint.

Description

Technology Field

[0001] The present invention relates to a remotely operated load handling device on a track located on a grid framework structure for handling storage containers or boxes stacked on a grid framework structure, and more specifically, to a grid framework structure for supporting a remotely operated load handling device. Background Technology

[0002] A storage system (1) comprising a three-dimensional storage grid structure in which storage containers / boxes are stacked on top of each other is well known. PCT publication number WO2015 / 185628A (Ocado) describes a known storage and transfer system in which a stack of boxes or containers is placed within a grid framework structure. The boxes or containers are accessed by a remotely operated load handling device on a track located at the top of the grid framework structure. This type of system is schematically illustrated in FIGS. 1 to 3 of the attached drawings.

[0003] As shown in FIGS. 1 and 2, stackable containers (known as boxes or containers (10)) are stacked vertically on top of each other to form a stack (12). This stack (12) is placed inside a grid framework structure (14) in a warehouse or manufacturing environment. The grid framework consists of a plurality of storage columns or grid columns. Each grid within the grid framework structure has at least one grid column for storing the container stack. FIG. 1 is a schematic perspective view of the grid framework structure (14), and FIG. 2 is a plan view of the stack (12) of boxes (10) placed inside the grid framework structure (14). Each box (10) generally contains a plurality of products (not shown), and the products inside the box (10) may be the same or different types of products depending on the use.

[0004] The grid framework structure (14) includes a plurality of upright members or upright columns (16) that support horizontal members (18, 20). Each of the plurality of upright members has a cross-sectional profile including a hollow center section and four corner sections, and each of the four corner sections includes two vertical guide plates extending along the longitudinal length of the upright member to cooperate with the corners of the storage container when the storage container is guided along the upright member.

[0005] A plurality of upright columns are interconnected at their top ends by a first set of parallel grid members (18) extending in a first direction and a second set of grid members (120) extending in a second direction. The first set of parallel horizontal grid members (18) are positioned perpendicularly to the second set of parallel horizontal grid members (20) to form a grid structure or grid (14b) that is placed on a horizontal plane containing a plurality of grid cells (15) and supported by upright members (16). For the purpose of describing the invention, the intersections where grid members cross or intersect each other in the grid structure constitute nodes of the grid structure. Generally, a connecting plate is used to connect or join grid members to upright members at the intersections. For example, the connecting plate is cross-shaped with four connecting parts for connecting to the ends of adjacent grid members in the grid structure. However, there are other means of connecting a plurality of grid members to a plurality of upright members within the grid structure in addition to using a cap plate. WO2018146304 (Autostore Tech AS) teaches a rail device for a wheeled vehicle in a storage system comprising a first set of parallel rails and a second set of parallel rails. The first and second sets of parallel rails form a grid in which the second set is positioned perpendicular to the first set and intersects the first set to form a grid of parallel rails. The rail comprises a plurality of elongated elements having an outer ridge and a center ridge defining a double track, and the elongated elements further comprise a middle ridge-free section, and the intersecting elements in the X and Y directions are positioned to overlap in their respective ridge sections to define a ridge intersection.

[0006] The upright members (16) and grid members (18, 20) are typically made of metal and are typically welded or bolted together, or a combination of both. The box (10) is stacked between the members (16, 18, 20) of the grid framework structure (14), so that the grid framework structure (14) inhibits the horizontal movement of the stack (12) of the box (10) and guides the vertical movement of the box (10).

[0007] The top level of the grid framework structure (14) includes a track system comprising rails or tracks (22) arranged in a grid pattern across the top of the stack (12). The rails or tracks may be integrated into the grid members, or alternatively, the track system may be formed as a part separate from the plurality of grid members, in which case the grid members function to support the track system. Referring further to FIG. 3, the rails (22) support a plurality of load handling devices (30) to form a storage and retrieval system (1). A parallel rail (22) of the first set (22a) guides the movement of the robotic load handling device (30) in a first direction (e.g., X-direction) across the top of the grid framework structure (14), and a parallel rail (22) of the second set (22b), which is positioned perpendicular to the first set (22a), guides the movement of the load handling device (30) in a second direction (e.g., Y-direction) perpendicular to the first direction. In this way, the robotic load handling device (30) can move laterally in two dimensions by means of the rail (22) in the horizontal XY plane, so that the load handling device (30) can move to a position on any stack (12).

[0008] A rail or track generally comprises an elongated element profiled to guide a load handling device on a grid structure, and is typically profiled to provide a single track surface to allow a single load handling device to move on the track, or to provide a double track surface to allow two load handling devices to pass each other on the same track. If the elongated element is profiled to provide a single track, the track includes opposing lips along the length of the track (one lip on one side of the track and another lip on the other side of the track) to guide each wheel on the track or to restrain the wheel from lateral movement. If the profile of the elongated element is a double track, the track includes two pairs of lips along the length of the track to allow the wheels of adjacent load handling devices to pass each other in both directions on the same track. To provide two pairs of lips, the track generally includes a center ridge or lip and lips on both sides of the center ridge. In all cases, when traversing on a grid structure, the wheels of the load handling device are constrained on both sides or faces of the load handling device wheels. To prevent the wheels of the load handling device from derailing, the allowable tolerances between adjacent track elements in the grid structure are very strict. To accommodate track movement caused by temperature differences that induce expansion and contraction of the track, which can lead to rail buckling or tension, one or more thermal expansion joints are integrated within the track system to connect areas of the track system, providing slight relief as a result of the movement of the track areas.

[0009] WO20200774257 (Autostore Technology AS) relates to an expansion joint for connecting areas of a rail-based grid storage system, wherein the expansion joint comprises a first rail element and a second rail element, the rail elements are elongated and configured to slide longitudinally relative to each other in an overlapping joint area, the expansion joint has a profiled upper surface defining one or more tracks for supporting a container handling device, the track extends from the first rail element through the joint area to the second rail element, in the joint area, each rail element provides a portion of the track of the profiled upper surface, so that there is a transition extending along the expansion joint from the first rail element to the second rail element for each track.

[0010] The known load handling device (30) shown in FIGS. 4 and 5, including a vehicle body (32), is described in PCT patent publication WO2015 / 019055 (Ocado), which is incorporated herein by reference, and each load handling device (30) covers only one grid space of the grid framework structure (14). Here, the load handling device (30) comprises a first set of wheels (34) consisting of a pair of wheels at the front of the vehicle body (32) and a pair of wheels (34) at the rear of the vehicle body (32), which are coupled to a first set of rails or tracks to guide the movement of the load handling device in a first direction, and a second set of wheels (36) consisting of a pair of wheels (36) at each side of the vehicle (32), which are coupled to a second set of rails or tracks to guide the movement of the load handling device in a second direction. Each wheel of the set is driven to allow the vehicle to move along the rails in the X and Y directions, respectively. One or both sets of wheels can be moved vertically to lift each set of wheels off their respective rails, allowing the vehicle to move in the desired direction.

[0011] The load handling device (30) is equipped with a lifting device or crane mechanism to lift a storage container from above. The crane mechanism includes a winch tether or cable (38) wound on a spool or reel (not shown) and a grabber device (39). The lifting device includes a set of lifting tethers (38) that extend vertically and are connected to or near the four corners of the lifting frame (39) (also called the grabber device) for a releaseable connection to the storage container (10) (there is one tether near each of the four corners of the grabber device). The grabber device (39) is configured to releaseably grasp the top of the storage container (10) to lift the storage container from a stack of containers in a storage system of the type shown in FIGS. 1 and 2.

[0012] Wheels (34, 36) are positioned around the periphery of a cavity or recess (known as a container receiving space (40)) in the lower portion. As shown in FIG. 5 (a and b), the recess is sized to accommodate the container (10) when the container is lifted by a crane mechanism. When in the recess, the container is lifted away from the rail below, so that the vehicle can move to another location sideways. When a target location, such as another stack, an access point within the storage system, or a conveyor belt, is reached, the box or container can be lowered from the container receiving portion and released from the grabber device. The container receiving space is not limited to a container receiving space (40) located within the vehicle body (32). The container receiving space may be located under a cantilever, such as when the vehicle body of the load handling device has a cantilever structure as described in WO2019 / 238702 (Autostore Technology AS). For the purposes of the present invention, the term “vehicle body” is interpreted to optionally encompass a cantilever that allows a grabber device to be positioned below the cantilever.

[0013] To access the contents of the storage container, most of the grid columns are storage containers, that is, grid columns in which storage containers are stored in a stack. However, the grid structure generally has at least one grid column that is not used to store the storage container, and this grid column includes a location or grid cell (15), in which a load handling device can lower and / or lift the storage container, so that the storage container can be transported to a second location (not shown in the drawings of the prior art), in which the storage container can be accessed from the outside of the grid or transferred out of or into the grid. In the art, such a location or grid cell is generally referred to as a "port," and the grid column in which the port is located may be referred to as a "transfer column." The storage grid includes two transfer columns. The first transfer column may include a dedicated drop-off port through which a container handling vehicle can unload a storage container to be transported to an access station or a transfer station, for example, and the second transfer column may include a dedicated pickup port through which a container handling vehicle can pick up a storage container transported through the transfer column from an access or transfer station. The storage container is supplied into the access station and exits the access station through the first transfer column and the second transfer column, respectively.

[0014] When a customer order is received, a load handling device operating to move on a track is instructed to pick up a storage box containing the ordered item from a stack of grid framework structures and transport the storage box to a pick station via a transfer column so that the item can be retrieved from the storage box. Typically, the load handling device transports the storage box or container to a box lift device integrated into the grid framework structure. The mechanism of the box lift device lowers the storage box or container to the pick station, where the item is retrieved from the storage box. Picking can be performed manually by hand or by a robot as taught in GB2524383 (Ocado Innovation Limited). After retrieval from the storage box, the storage box is transported to a second box lift device, where it is lifted to a pick port at the grid level, retrieved by the load handling device, and transported back to a position within the grid framework structure.

[0015] A separate area accommodating an access station is provided adjacent to the storage column so that a load handling device can lower a storage container to a pick station or pick it up from there. Typically, the separate area is provided by integrating a mezzanine supported by vertical beams between adjacent grid framework structures. The mezzanine provides a separate space capable of accommodating one or more pick stations. Typically, the separate area is a tunnel with grid framework structures on both sides of the tunnel. A grid structure from the adjacent grid framework structure extends across the top of the mezzanine and connects to the grid structures on both sides of the mezzanine, so that the grid structure lies in a substantially horizontal plane. One or more transfer and / or pick-up ports are assigned to one or more grid cells of the grid structure extending across the mezzanine, so that a load handling device operating on the grid structure can lower a storage container or pick up a storage container from a pick station below. As a result of the grid structure extending across the mezzanine, the grid structure at the top of the mezzanine tends to be shallower than the grid framework structures on either side of the mezzanine, meaning it can accommodate only one or two layers of containers in the stack. The mezzanine is supported by separate vertical beams. The vertical beams supporting the mezzanine are in contact with the grid framework structures on either side of the mezzanine. In addition to one or more fix stations, the separate area created by the mezzanine can accommodate various other stations, including (but not limited to) a charging station for charging rechargeable batteries that power the load handling device and a service station for performing routine maintenance on the load handling device. As such stations require manual labor, one or more employees will tend to be located under the mezzanine.This includes, but is not limited to, pickers at pick stations, service staff at work stations, etc.

[0016] Grid framework structures are subjected to various external and internal forces. These forces include, but are not limited to, ground movement that may occur due to the composition of the ground or soil type, forces caused by the movement of load handling devices (which may have a weight exceeding 100 kg) on ​​the grid framework structure, movement caused by nearby construction, moving vehicles such as trains, or even movement during earthquakes or storms. To ensure the stability of the grid framework structure, conventional storage and retrieval systems rely primarily on various supports and bracing members placed within the grid or at least partially along the periphery of the grid. However, using various supports and bracing members (movement-restraining bracing members) to stabilize the grid framework structure against internal and external forces is disadvantageous for several reasons. The grid framework structure occupies space or area that can be utilized by the grid for storing containers, in that it hinders the optimal use of available space or area for container storage. Because auxiliary grid support structures often require connections to surrounding structures, such as the interior walls of a building, and because the support structure is not cost-effective, the need for support structures can limit the available lines of support for positioning grid framework structures.

[0017] WO2019 / 101367 (Autostore Technology AS) teaches a grid support structure for integration into a storage grid structure of an deployed automated storage system. This grid support structure consists of four storage columns connected to one another by a plurality of vertically inclined support struts. The storage column profile has a cross-section including a hollow center section and four corner sections, each corner section including two vertical box guide plates to accommodate the corners of storage boxes. The support struts have a width that allows the support struts to be sandwiched between two parallel guide plates so as not to impair the storage column's ability to accommodate stacks of containers or storage boxes.

[0018] While some movement within the grid framework structure is considered acceptable to provide relief to the track system as a result of thermal expansion, excessive movement of the grid framework structure will not be considered acceptable, as it may damage the structural fasteners holding the grid framework structure together.

[0019] The majority of the world's population lies along seismic fault lines or in the paths of powerful storms such as hurricanes and tornadoes. Placing grid framework structures in these regions poses a risk of structural damage from earthquakes and storms, as current grid frame structures may fail to hold the grid structure together. The occurrence of powerful earthquakes and storms can cause a failure of their structural integrity; for example, as a result, structural fasteners may become unable to keep the grid firmly attached to the upright members. Earthquakes can be classified into four types—Type A, Type B, Type C, and Type D—based on their intensity, with Type A being the weakest and Type D being the strongest. Types A through D can be graded according to spectral acceleration, which is the maximum acceleration (measured in g) experienced by objects on the ground during an earthquake. Type D is considered to represent the most powerful earthquake occurrences and generally has spectral accelerations measured in the 0.5g to 1.83g range (see Short-term Spectral Response Acceleration SDS, https: / / www.fegstructural.com / seismic-design-category-101 / ), causing failure of most buildings. When a powerful earthquake acts on a structure, three dynamic forces damage the structural fasteners that hold the grid framework structure together, causing the fasteners to loosen or come out of the members in which they are embedded, or, if they remain in place, the fasteners can tear through the structural elements.

[0020] While the ground moves due to an earthquake, grid framework structures tend to vibrate. The vibration of grid framework structures can be described by transverse and longitudinal waves. Longitudinal waves are waves in which the displacement of the grid framework structure is in the same direction as the movement of the ground, while transverse vibrations are perpendicular to the movement of the ground. In both cases, the amplitude of the vibration of the grid framework structure depends significantly on the degree of ground movement, and that ground movement depends on the category of the earthquake. In the case of a Category D earthquake, the amplitude of the vibration is much larger than that of a Category A earthquake. Since the upright members of the grid framework structure are interconnected at their upper ends by multiple grid members extending in the first and second directions, bending moments can occur as a result of the movement of the grid framework structure concentrating at the joints where the grid members cross or intersect the vertical upright members. Thermal expansion joints provide some degree of mitigation of movement in the track system to prevent derailment of the load handling device, but this may not be the case if the movement of the track system is excessive, causing the structural fasteners of the interconnects to loosen or, in the worst case, fail during an earthquake. The structural fasteners interconnecting the grid members are subjected to bending moments due to ground movement, and the supporting members supporting the structural fasteners and / or upright members are subjected to excessive forces. The forces experienced at the interconnects are exacerbated for higher grid framework structures as a result of the amplitude of vibrations in the grid framework structures.

[0021] Individual containers can be stacked in vertical layers, and their position within the grid framework structure or "hive" can be indicated using three-dimensional coordinates to represent the location of the load handling device or container and the container depth (e.g., container with (XY, Z) and depth (W)). Likewise, the position within the grid framework structure can be indicated in two dimensions to represent the location of the load handling device or container and the container depth (e.g., container with depth (e.g., (X, Y) and depth (Z))). For instance, Z=1 represents the top layer of the grid, that is, the layer immediately below the rail system, Z=2 represents the second layer below the rail system, and so on, up to the bottom layer of the grid. Considering that the depth (Z) can be as high as 21 levels and the height of a typical storage container can be 30 to 40 cm, the amplitude of vibration in the grid framework structure can be significantly large during an earthquake.

[0022] As a rough example of the vibration of a grid framework structure fixed to the ground equivalent to the oscillation of a pendulum, the displacement(s) of the grid framework structure from the vertical during ground movement can be given by the following equation:

[0023] s = L × θ (1)

[0024] Here, L is the effective height of the grid framework structure and θ is the angle the grid framework structure makes with the vertical. When θ is expressed in radians, s is taken as the vibration amplitude of the grid framework structure. Thus, according to Equation (1), the greater the height of the grid framework structure, the greater the vibration amplitude of the grid framework structure during ground movement. Due to excessive vibration of the grid framework structure caused by an earthquake, structural fasteners holding the grid members and / or upright members together may weaken, and in the worst case, the grid framework structure may collapse. Considering that people are working beneath the grid structure, particularly at the mezzanine level, as described above, the lives of people below the mezzanine level could be endangered if the grid framework structure collapses. In addition to the area of ​​the grid framework structure breaking, the vibration of the grid framework structure makes it easy for storage containers and / or their contents stacked between the upright members to be thrown around. To mitigate the risk of injury to people in the event that the grid framework structure breaks or, in the worst case, collapses, a grid framework structure is required that isolates the area of ​​the grid framework structure where people are present.

[0025] A thermal expansion joint configured to allow the expansion and contraction of a grid member in a grid framework structure relies on the sliding arrangement of track elements in only one direction to avoid the wheels of a robotic load handling device derailing from the track. Therefore, to accommodate the thermal expansion of the grid member in the X and Y directions, a separate thermal expansion joint connecting the grid member in the X and Y directions is required. The present invention alleviates the need for a separate thermal expansion joint relying on the sliding arrangement of track elements in both X and Y directions by making at least one connection of the grid member to an upright member rotatable so that the grid member can rotate about a vertical axis in the horizontal plane when the grid member moves in a direction substantially perpendicular to the longitudinal axis along the grid member. More specifically, the present invention provides a grid framework structure for supporting a load handling device operated to move one or more containers, wherein the grid framework structure comprises

[0026] It includes a plurality of upright members arranged to form a plurality of vertical positions for being guided by an upright member in a vertical direction, and

[0027] A plurality of upright members are interconnected to define nodes at normal ends by a plurality of grid members arranged in a grid pattern comprising a first set of grid members extending in a first direction and a second set of grid members extending in a second direction, wherein the second set of grid members is transverse to the first set of grid members in a substantially horizontal plane to form a grid structure comprising a plurality of grid cells,

[0028] The grid structure includes a track system positioned on a plurality of grid members, and the track system includes a plurality of tracks arranged in a grid pattern.

[0029] A plurality of upright members includes a first upright member and a second upright member, and these upright members are interconnected by at least one of a plurality of grid members extending between the first upright member and the second upright member, and the first upright member is interconnected by at least one of the plurality of grid members by a connecting portion including a pivotable joint at its normal end, so that when one of the first or second upright members moves relative to the other of the first or second upright member, at least one of the plurality of grid members can rotate in a horizontal plane about a vertical axis extending through the pivotable joint.

[0030] In the present invention, a plurality of upright members comprises a first upright member and a second upright member, and these upright members are interconnected by at least one of a plurality of grid members extending between the first upright member and the second upright member, and the first upright member is interconnected by at least one of the plurality of grid members by a connecting portion including a pivotable joint at its normal end, so that when one of the first or second upright member moves relative to the other of the first or second upright member, at least one of the plurality of grid members can rotate in a horizontal plane about a vertical axis extending through the pivotable joint. By means of the pivotable connecting portion between at least one grid member and the upright member, at least one grid member can move in a horizontal plane in a direction substantially perpendicular to the longitudinal direction of at least one grid member. In other words, by means of a pivotable joint that interconnects at least one of the plurality of grid members to an upright member, when one of the first or second upright members moves relative to the other of the first or second upright members, the grid member can rotate in a horizontal plane around a vertical line extending through the pivotable joint.

[0031] Due to ambient temperatures or temperature differences within the building or area where the grid structure is placed, the grid members expand and contract, causing them to move. This can potentially lead to buckling or distortion of the track, and consequently, there is a risk that the wheels of the robotic load handling device may derail from the track. A known thermal expansion joint, as taught in WO2020074257 (Autostore Technology AS), compensates for movement parallel to the longitudinal direction of the grid member, i.e., in the X or Y direction, but it does not compensate for movement in both the X and Y directions, i.e., substantially perpendicular to the longitudinal direction of the grid member, because the thermal expansion joint may only be suitable for movement in one direction, namely along the longitudinal direction of the grid member. Preferably, at least one of the grid members interconnecting the first and second upright members comprises an expansion joint, the expansion joint further comprises a first track element and a second track element, and a bridging joint member extends across the ends of the first and second track elements to provide a continuous track surface extending longitudinally in a first or second direction across the ends of the first and second track elements, and the bridging member has a first end attached to the first track element and a second end movable longitudinally with respect to the second track element. At least one grid member may rotate about a vertical axis extending through one of its interconnecting parts, and at least one grid member may be extended longitudinally by the bridging member. The pivotable joint, together with the expansion joint, defines an improved expansion joint that allows movement of the grid member in both X and Y directions in a horizontal plane. Thus, the expansion joint, together with the pivotable joint of the present invention, can accommodate movement in both X and Y directions in a horizontal plane.For example, a pivotable joint allows one of the first or second upright members to move relative to the other of the first and second upright members through the Y direction, and a bridging member allows one of the first or second upright members to move longitudinally along the X direction relative to the other of the first and second upright members.

[0032] To control the rotational movement of at least one grid member interconnected between a first upright member and a second upright member, preferably, the connection further comprises at least one arched slot through which a stop member passes, the arched slot having a radius of curvature centered on a pivotable joint, so that at least one of the plurality of grid members can rotate about the pivotable joint at a predetermined angle defined by the arc of the arched slot. If the movement of the grid framework structure is affected by an external force, such as in an earthquake, optionally, the stop member comprises a mechanical fuse positioned to break if a load applied in a first direction or a second direction exceeds or equals a predetermined load. The curvature of the arc defines a predetermined angle of rotation of at least one of the plurality of grid members. The arched slot allows rotational movement of at least one of the plurality of grid members. The predetermined angle may be in the range of 1° to 20°, preferably in the range of 5° to 20°. Optionally, the mechanical fuse comprises a shear pin. A shear pin allows at least one grid member to rotate beyond a predetermined angle determined by the curvature of the arched slot when the force rotating at least one grid member exceeds or is equal to a predetermined load for breaking a mechanical fuse. The shear pin may be called a fuse bolt or a separation bolt.

[0033] To control the longitudinal linear movement of the track element of the expansion joint, the second end of the bridge member is configured to be received in a correspondingly formed receiving recess in the second track element. Optionally, the second end of the bridge member is positioned to overlap with the second track element. Preferably, the bridge member further comprises a guide member constrained to slide along a groove of the second track element. Separation of the first and second track elements creates a gap between the ends of the first and second track elements, and this gap is filled by the bridge member. However, there is now a risk that at least a portion of the bridge member will bend due to the weight of a robotic load handling device moving across the bridge member in the joint area where the ends of the first and second track elements are separated. Preferably, the thermal expansion joint assembly further comprises a support member positioned to support the bridge member in the joint area between the ends of the first track element and the second track element.

[0034] To interconnect upright members to a grid member, preferably, the connecting member comprises a bracket, the bracket having a first end fixedly connected to the top end of a first upright member and a second end pivotally connected to at least one of a plurality of upright members by a pivotable joint. Optionally, the first end of the bracket comprises a spigot positioned to be fixed to the top end of the first upright member, and the second end comprises at least three connecting portions that are substantially perpendicular to each other, each of the at least three connecting portions being connected to an individual grid member of the grid structure, and at least one of the individual grid members being connected to at least one of the at least three connecting portions by a pivotable joint, so that at least one of the individual grid members is rotatable in a horizontal plane about a vertical axis defined by the pivotable joint. Optionally, at least one of the plurality of grid members extending between the first upright member and the second upright member is connected to the second upright member by a bracket of the second type, and the bracket defines the bracket of the first type, and the bracket of the second type is different from the bracket of the first type. Various bracket types may be used to connect the grid member to the upright member so that the grid member can rotate about a vertical axis. The type of bracket used to connect the grid member to the first upright member may differ from the bracket used to connect the grid member to the second upright member, and mainly depends on the type of grid member connected to both sides of the first and second upright members. For example, different types of grid members may be used for different areas of the grid structure that provide different functional characteristics. Different functional characteristics may be different structural characteristics of different areas of the grid structure, such as seismic resilience levels.Due to different types of grid members used in different areas, different bracket types may be required to combine or connect different areas of the grid structure. Optionally, the plurality of grid members comprises a plurality of first type grid members arranged in a grid pattern to define a first area of ​​the grid structure and a plurality of second type grid members arranged in a grid pattern to define a second area of ​​the grid structure, such that at least one of the plurality of first type grid members is interconnected to a first upright member in the first area of ​​the grid structure and at least one of the plurality of second type grid members is interconnected to a second upright member in the second area of ​​the grid structure, and the plurality of first type grid members are different from the plurality of second type grid members. Optionally, the cross-sectional profile of each of the first type grid members is substantially I-shaped, and each of the second type grid members includes a hollow portion. A first region of the grid structure may extend above a mezzanine level, where a service station such as a pick station is located below that mezzanine level, and a second region of the grid structure is positioned above a plurality of vertical storage columns where one or more stacks of storage containers are stored. Typically, one or more of the grid cells in the first region of the grid structure are dedicated as one or more pick-up ports and / or transfer ports. These ports are used to store storage containers. Consequently, the grid members constituting the first region of the grid structure do not need to have the same level of structural stiffness as the grid members constituting the second region of the grid structure. For example, the first type of grid member constituting the first region of the grid structure may be formed as a butt-to-butt C-section having a substantially I-shaped cross-sectional profile, and the second type of grid member constituting the second region of the grid structure may be based on a tubular beam having a hollow section.Compared to beams of other shapes, using a tubular beam to form a grid member provides greater resistance to bending because the walls of the tubular beam can resist bending in all directions. In one example, a first end of the bracket includes a spigot positioned to be fixed to the top end of a first upright member, and a second end includes at least three connecting parts that are substantially perpendicular to each other, each of which is connected to an individual grid member of the grid structure, and at least one of the individual grid members is connected to at least one of the at least three connecting parts by a pivotable joint, so that at least one of the individual grid members can rotate in a horizontal plane about a vertical axis defined by the pivotable joint. Here, the grid member can be rotatably connected to at least one of the three connecting parts by a pivotable joint. For example, the bracket may be cross-shaped having four vertical connecting parts defining a cap plate. When the grid structure is composed of different types of grid members, namely first and second types of grid members defining the first and second regions of the grid structure, respectively, preferably, at least one of a plurality of grid members extending between the first upright member and the second upright member is connected to the second upright member by a second type bracket, the bracket defines the first type bracket, and the second type bracket is different from the first type bracket. Due to the difference in size of the cross-sectional profiles of the first and second types of grid members, the second type bracket ensures that the grid structure is maintained substantially horizontal when transitioning from the first region of the grid structure to the second region of the grid structure.

[0035] A bracket of the second type has a first end having an upper connecting portion for connecting to at least one grid member so that at least one of the plurality of grid members can rotate, a second end having a lower connecting portion for connecting to a second upright member, and a vertical column extending between the upper connecting portion and the lower connecting portion. The vertical separation between the upper connecting portion and the lower connecting portion ensures that at least one grid member is maintained substantially horizontally or at the same height during a transition between a first area of ​​the grid structure and a second area of ​​the grid structure.

[0036] The present invention further provides a storage and retrieval system, wherein the system is,

[0037] i) A grid framework structure as defined in the present invention;

[0038] ii) A plurality of stacks of containers placed in storage columns located below the grid - each storage column is positioned vertically below the grid cell -; and

[0039] iii) Includes a plurality of load handling devices for lifting and moving containers stacked in a stack, and

[0040] Multiple load handling devices are operated remotely and move laterally on the grid above the storage column to access the container through the grid cell, and each of the multiple load handling devices is,

[0041] a) A wheel assembly for guiding a load handling device on a grid;

[0042] b) a container receiving space located above the grid; and

[0043] c) Includes a lifting device positioned to lift a single container from a stack into a container receiving space. Brief explanation of the drawing

[0044] Further features and aspects of the present invention will become apparent from the following detailed description of exemplary embodiments made with reference to the drawings. Figure 1 is a schematic diagram of a grid framework structure according to a known system. FIG. 2 is a schematic plan view showing a stack of boxes placed within the framework structure of FIG. 1. FIG. 3 is a schematic diagram of a system of a known load handling device operating on a grid framework structure. FIG. 4 is a schematic perspective view of a load handling device showing a lifting device holding a container from above. FIGS. 5A and FIGS. 5B are schematic cutaway perspective views of the load handling device of FIG. 4, showing (a) a container accommodated within the container receiving space of the load handling device and (b) the container receiving space of the load handling device. Figure 6 is a plan view of one section of a grid structure showing adjacent grid cells. FIG. 7 is a perspective view showing the arrangement of upright members forming a vertical storage column for stacking containers between upright members. FIG. 8a is a perspective view of the arrangement of upright members in a grid pattern forming a plurality of adjacent vertical storage columns. FIG. 8b is a side view of a plurality of storage containers stacked on a vertical storage column. FIG. 9 is a perspective view showing the arrangement of grid members formed by tracks interconnected at nodes or intersections by cap plates and track supports. Fig. 10 is a perspective view of the track support section. FIG. 11 is a perspective view of a cap plate for interconnecting vertical upright members to grid members at a node. FIG. 12 is a perspective view of a cap plate installed on an upright column to connect adjacent grid members together at an intersection where grid members intersect, according to one embodiment of the present invention. FIG. 13 is a perspective cross-sectional view of the interconnection of vertical upright members to grid members by cap plates at the nodes. FIG. 14 is a perspective view of a track or rail. FIG. 15 is a schematic diagram of a known implementation center showing a mezzanine between adjacent grid framework structures. FIG. 16 is a perspective view of a part of a grid framework structure in a joint area where a grid structure interconnecting vertical storage columns meets a grid structure extending above a mezzanine level, according to one embodiment of the present invention. FIG. 17 is a perspective plan view of the grid structure shown in FIG. 16, showing the connection of different regions of the grid structure by the cross-linked joint assembly according to the present invention. FIG. 18 is a perspective view of a cross-linked joint assembly according to the present invention. FIG. 19 is a perspective view showing a bridge joint assembly as one or more connecting parts between different regions of a grid structure according to the present invention. FIG. 20 is a cross-sectional view of a grid member joined by the cross-linked joint assembly of the present invention. FIG. 21 is a perspective view showing the breakage of a mechanical fuse separating the ends of a grid member according to the present invention. FIG. 22 (a to c) is a perspective view showing different steps of (a) a closed configuration; (b) a partially open configuration; and (c) separation of a grid member from an open configuration according to the present invention. FIG. 23 (a and b) is a perspective view of an expansion joint showing a slide connection of a track element, wherein (a) is a plan view of the expansion joint according to the present invention; and (b) is a side view of the expansion joint. FIG. 24 is a perspective view of a slide connection portion of a track element showing the fixation of a track element along a runner of a grid member according to the present invention. FIG. 25 is a perspective view of another example of a slide connection portion of a track element according to the present invention. FIG. 26 is a perspective view of an expansion joint including a slide connection portion of a track element illustrated in FIG. 25 for connecting the ends of a grid member according to the present invention. FIG. 27 is a schematic diagram of a wheel of a robotic load handling device constrained by a track of a sliding connection part according to the present invention. FIG. 28 is a perspective cross-sectional view of a seismic grid structure showing a cross-sectional profile of a grid member according to one embodiment of the present invention. FIG. 29 is a schematic plan view of a partial frame of a grid of a seismic grid frame structure according to an embodiment of the present invention. FIG. 30 is a schematic bottom view of a partial frame of a grid of a seismic grid framework structure according to an embodiment of the present invention. FIG. 31 is a cross-sectional view showing the connection of a track to a track support portion of a grid element of a seismic grid structure according to an embodiment of the present invention. FIG. 32 is a perspective view of a part of a grid framework structure in a joint area between a seismic grid structure and a grid structure extending above a mezzanine level according to an embodiment of the present invention. FIG. 33 is a perspective view of different brackets used to connect a cross-linked joint assembly to different types of grid members of a grid structure according to the present invention. FIG. 34 is a perspective plan view of the pivot connection of a grid member to a cap plate for interconnecting upright members according to the present invention. FIG. 35 is a perspective side view of the pivot connection of a grid member to a cap plate according to the present invention. FIG. 36 is a perspective view of a section of a misaligned track resulting from the rotation of a grid member according to the present invention. FIG. 37 is an enlarged view of the misaligned track shown in FIG. 36 according to the present invention. FIG. 38 is a perspective view of a cap plate showing at least one connecting portion including an arched slot for receiving a stop member according to the present invention. FIG. 39 is a perspective view of another example of a second bracket for pivotally connecting a grid member according to the present invention to an upright member. FIG. 40 is a perspective view of a rotated grid member between adjacent upright members joined together by the cross-linked joint assembly of the present invention. FIG. 41 is a front view of a pivotable connection portion of a grid member for a second bracket shown in FIG. 39 according to the present invention. FIG. 42(a and b) is a perspective view of a stop member functioning as a mechanical fuse to control the rotation of a grid member relative to a connecting upright member, and shows a stop member in (a) an intact configuration and (b) a broken configuration according to the present invention. FIG. 43 is a perspective view showing a cross-section of a pivotable connection portion including a pivotable joint and a stop member between a grid member and a second bracket according to the present invention. FIG. 44 is a perspective view of the pivotable connection of FIG. 43 showing the breakage of the stop member allowing rotation of the grid member relative to the upright member according to the present invention. FIG. 45 is a perspective view showing the rotation of a track element relative to another track element that intersects at an angle greater than a predetermined angle through the breakage of a stop member according to the present invention. FIG. 46 is a plan view showing the interface portion of the first and second track elements according to another embodiment of the present invention. FIGS. 47 (a to c) is a plan view of the first and second track elements of FIG. 46 in (a) a closed configuration and (b) a partially open configuration. FIGS. 48(a and b) is a plan view of an expansion joint according to an embodiment of FIG. 46 having (a) a closed configuration and (b) an open configuration. FIG. 49 is a perspective view of an expansion joint according to an embodiment of FIG. 46, showing a wheel of a load handling device constrained by a guide surface. FIG. 50 is a perspective view of an expansion joint according to an embodiment of FIG. 46, showing a track element supported by a sliding connection of a back-butt C-section track support. FIG. 51 is a perspective view of an expansion joint according to an embodiment of FIG. 46, showing a track element as a box section supported by a sliding connection. Specific details for implementing the invention

[0045] Grid framework structure

[0046] The present invention is conceived with respect to known features of storage systems and load handling devices, such as the grid framework structure described above with reference to FIGS. 1-5. FIG. 6 shows a plan view of one section or part of a traditional grid structure (50) comprising four adjacent grid cells (42), and FIG. 7 shows a side perspective view of a single grid cell (42) supported by four vertical upright members (16) to form a single vertical storage column (44) for storing one or more containers (10) in a stack. FIGS. 8 (a and b) shows a perspective view of upright members arranged to form a vertical storage column (44) for containers (10) to be stored within the vertical storage column (44). FIG. 8b shows a vertical stack of containers (10) between the upright columns (16).

[0047] Each vertical upright member (16) is generally tubular. In the cross-section in the horizontal plane of the storage column (44) shown in FIG. 2, each vertical upright member (16) includes a hollow center section (46) (typically a box section), and one or more guides (48) extending along the longitudinal length of the vertical upright member (16) are mounted or formed at the corners of the hollow center section (46) to guide the movement of containers along the vertical storage column (44). One or more guides (48) include two vertical container guide plates. The two vertical container guide plates are positioned to accommodate the corners of the containers or the corners of the container stack. In other words, each corner of the hollow center section (46) defines two sides of a substantially triangular area capable of accommodating the corners of the containers or storage boxes. The corners are evenly distributed around the hollow center section (46), so that a number of vertical uprights (16) can provide a number of adjacent storage columns, and each vertical upright (16) can be common or shared for up to four individual storage columns. Also, as shown in FIG. 7, each vertical upright (16) is mounted on an adjustable grid leveling mechanism (19) at the foot of the vertical upright, which includes a screw shaft and a base that can be extended or retracted to compensate for an uneven floor.

[0048] As seen in the cross-section of the storage column (44) in the horizontal plane of FIG. 2, the individual storage column (44) consists of four vertical uprights (16) positioned at the corners of the container or storage box (10). The storage column (44) corresponds to a single grid cell. The cross-section of the vertical uprights (16) is constant over the entire length of the vertical uprights. In the horizontal plane of FIG. 2, the periphery of the container or storage box shows the container or storage box having four corners and the arrangement of the four vertical uprights (16) at the corners of the container or storage box within the vertical storage column (44). One from each of the four vertical uprights, the corner portion of each of the four vertical uprights ensures that the container or storage box stored in the storage column (44) is guided to the correct position relative to the stack of containers or storage boxes stored within the storage column and the periphery of the storage column. A robotic load handling device (not shown) operating on a grid structure (50) can lift a container or storage box as the container or storage box is guided along a vertical upright member (16) through a grid cell (42). Thus, the vertical upright member (16) has a dual purpose of (a) structurally supporting the grid structure (50) and (b) guiding the container or storage box (10) to an accurate position through each grid cell (42).

[0049] A plan view of one section of the grid structure (50) shown in FIG. 6 shows a series of horizontal intersecting beams or grid members (18, 20) arranged to form a plurality of rectangular frames constituting a grid cell (42). More specifically, a first set of grid members (18) extends in a first direction (X) and a second set of grid members (20) extends in a second direction (Y), and the second set of grid members (20) are lateral to the first set of grid members (18) in a substantially horizontal plane, i.e., the grid structure is represented in Cartesian coordinates in the X and Y directions. The terms "vertical uprights(s)," "upright members(s)," and "upright columns(s)" are used interchangeably in the description to mean the same thing or feature. For the description of the invention, points or joints where grid members intersect or cross (shown as squares in FIG. 6) may be defined as nodes or intersections (52). As is evident from the layout of at least a part or section of the known grid structure (50) constituting four adjacent grid cells (42) shown in FIG. 6, each intersection or node (52) of the grid structure (50) is supported by vertical uprights (16), that is, both of them coincide. From the section or at least part of the grid structure (50) shown in FIG. 6, the four adjacent grid cells are supported by nine vertical uprights (16), that is, three sets of vertical uprights (16) supporting the grid structure in three columns, and each column includes three nodes (52).

[0050] Each grid member of the present invention may include a track support (18, 20) and / or a track or rail (22a, 22b) (see FIG. 9), so that the track or rail (22a, 22b) is mounted on the track support (18, 20). A load handling device operates to move along the track or rail (22a, 22b) of the present invention. Alternatively, the track (22a, 22b) may be incorporated into the track support (18, 20) as a single unit, for example by extrusion. In a specific embodiment of the present invention, the grid member includes a track support (18, 20) and the track or rail (22a, 22b) is mounted on the track support (18, 20). At least one grid member of a set, such as a single grid member, may be subdivided or divided into individual grid elements that can be joined or connected together to form a grid member (18, 20) extending in a first direction or a second direction (see FIG. 9 and 14). If the grid member includes a track support, the track support may be subdivided into individual track support elements connected together to form a track support (see FIG. 10 and 13). Individual track support elements constituting a track support extending in a first axial direction and a second axial direction are shown in FIG. 9. Individual track support elements (56) used to constitu the track support (18, 20) are shown in FIG. 10. In cross-section, the track support (18, 20) may be a solid support of a C-shaped, U-shaped, or I-shaped cross section, or even a double C-shaped or double U-shaped support. In a specific embodiment of the present invention, the track support element (56) includes double butt C sections that are bolted together.

[0051] A connecting plate or cap plate (58) as shown in FIGS. 9 and 11 may be used to connect or combine individual track support elements (56) together in both first and second directions at joints where multiple track support elements intersect at nodes (52) in the grid structure (50), namely, the cap plate (58) is used to connect the track support elements (56) together to the vertical upright (16). Consequently, the vertical upright (16) is interconnected by the cap plate (58) at its upper end at joints where multiple track support elements intersect in the grid structure (50), namely, the cap plate is located at nodes (50) of the grid structure (50). As shown in FIG. 11, the cap plate (58) is cross-shaped, having four connecting parts (60) to be connected at the ends of the track support elements (56) at the intersection (52) or at any point along their length. The track support element being interconnected to the vertical upright by a cap plate (58) at the node is shown in the cross-sectional profile of the node (52) shown in FIG. 13. The cap plate (58) includes a spigot or protrusion (62) sized to be seated in a tight fit in the hollow center section (46) of the vertical upright (16) to interconnect the plurality of vertical uprights (16) to the track support element as shown in FIG. 11 and 12. To prevent the cap plate from rotating about the vertical upright (16) around a vertical axis along the longitudinal axis of the vertical upright, the spigot (62) is received in a correspondingly formed opening in the vertical upright or upright member (16) in a snap-fit ​​arrangement. The spigot (62) includes downwardly extending elastic members that cooperate to be snap-fitted into the opening defined by the hollow center opening section (46) of the vertical upright.Also shown in FIG. 13 are track support elements (56a, 56b) extending in two vertical directions corresponding to a first direction (x-direction) and a second direction (y-direction). A connecting portion (60) is perpendicular to each other to connect the track support elements (56a, 56b) extending in the first and second directions. A cap plate (58) is configured to be bolted to the ends of the track support elements (56a, 56b) or along the length of the track support elements. Each track support element (56a, 56b) is arranged to interlock with each other at a node to form a grid structure (50) according to the present invention. To achieve this, the distal or mutually opposite ends of each track support element (56a, 56b) include a locking feature (64) for interconnecting with a corresponding locking feature (64) of an adjacent track support element. In a specific embodiment of the present invention, the mutually opposing or distal ends of one or more track support elements comprise at least one hook or tongue (64) that is received in an opening or slot (66) in the middle of an adjacent track support element (56) at a joint where the track support element intersects in the grid structure (50). Referring again to FIG. 10 in conjunction with FIG. 13, the hook (64) at the end of the track support element (56) is shown to be received in an opening (66) of an adjacent track support element that extends across a vertical upright (16) at a joint where the track support element (56) intersects. Here, the hook (64) is provided up to an opening (66) on both sides of the track support element (56b). In a specific embodiment of the present invention, the opening (66) is midway along the length of the track support element (56), so that when assembled together, adjacent parallel track support elements (56) in the first direction and the second direction are offset by at least one grid cell. This is shown in FIG. 9.

[0052] To complete the grid structure (50), once the track support elements (56) are interlocked to form a grid pattern including a track support member (18) extending in a first direction and a track support member (20) extending in a second direction, tracks (22a, 22b) are mounted on the track support elements (56). The tracks (22a, 22b) are snap-fitted and / or fitted onto the track support members (18, 20) in a slide-fit arrangement (see FIG. 9). Similar to the track support members of the present invention, the tracks include a first set of tracks (22a) extending in a first direction and a second set of tracks (22b) extending in a second direction, where the first direction is perpendicular to the second direction. A first set of tracks (22a) is divided into a number of track elements or elongated track elements (68) in a first direction, so that when assembled together, adjacent parallel track elements in the first direction are offset by at least one grid cell. Similarly, a second set of tracks (22b) is divided into a number of track elements (68) in a second direction, so that when assembled together, adjacent parallel track elements in the second direction are offset by at least one grid cell. This is shown in FIG. 9. An example of a single track element or elongated track element (68) is shown in FIG. 14, and this track element includes an elongated element profiled to guide a load handling device on a grid structure and also generally to provide a single track surface that allows a single load handling device to move on the track or a double track that allows two load handling devices to pass each other on the same track. A track surface is defined as a surface on which the wheels of the load handling device roll.When an elongated element is profiled to provide a single track, the track includes mutually opposing ribs or ridges along the longitudinal edges of the track to guide each wheel on the track or to restrain each wheel from lateral movement (one rib on one side of the track and another rib on the other side of the track). For the purposes of the present invention, the ribs or ridges along each longitudinal edge of the track are defined as guide surfaces for restraining the wheels of a load handling device on the track. When the profile of the elongated element is a double track as illustrated in the track element shown in FIG. 14, the track includes two ribs (69a, 69b) along the longitudinal edges of the track and a center rib or ridge (69c) parallel to those ribs along the edge of the track, i.e., the track includes three parallel ridges. As two ribs or ridges (69a, 69b) extend longitudinally along the edge of the track element, the two ribs (69a, 69b) at the edge of the track element are defined as the first edge guide surface and the second edge guide surface, respectively. A center rib or ridge (69c) is at an equal distance from each of the ribs or ridges at the edge of the track, so that the area between the center rib and the ribs at the edge of the track provides two track surfaces that allow the wheels of adjacent load handling devices to pass each other in both directions on the same track. In a specific embodiment shown in FIG. 14, the two ribs or ridges (69c) are shown to extend longitudinally along the center portion of the track in cooperation with the ribs (69a, 69b) at the edge of the track to provide track surfaces on both sides of the center ridge (69c). In all cases, when traversing on a grid structure, the wheels of the load handling device are restrained on both sides or faces of the load handling device wheels.Similar to track support elements, a plurality of elongated track elements in a first direction and a second direction are arranged together to form a track in both directions. The fit of the track element (68) to the track support (18, 20) comprises an inverted U-shaped cross-sectional profile formed to support or overlap the top of the track support (18, 20). One or more lugs extending from each branch of the U-shaped profile engage with the ends of the track support (18, 20) in a snap-fit ​​arrangement. The track element (68) includes a cutout or recess (70) that accommodates the track support element (56) in the upright column discussed above. Since the track element (68) is sized to extend or span across a single upright in the grid structure, the cutout (70) is formed at the center of each track element (68) or in the middle of the track element. In the present invention, it is also possible for the track (22a, 22b) to be integrated into the track support (18, 20) rather than being a separate component.

[0053] The grid framework structure (14) can be considered as a straight assembly of upright columns (16) supporting a grid structure (50) formed by intersecting horizontal grid members (18, 20), i.e., a four-walled framework. When a customer order is received, a load handling device operating to move on a track is instructed to pick up a storage box containing the ordered item from a stack in the grid framework structure and to transport the storage box to a pick station, whereby the item can be retrieved from the storage box and transferred to one or more delivery containers. Typically, the pick station includes a container transport assembly for transporting one or more containers to an access station where the contents of the containers can be accessed. The container transport assembly is typically a conveyor system comprising a plurality of adjacent conveyor units.

[0054] In a known fulfillment center as illustrated in FIG. 15, the goods and inventory required to fulfill a customer order are located in a container or storage box (10), and the container or storage box may be arranged along a passageway. On the opposite side of the passageway from the container or storage box, there is a conveyor system, which transports the customer delivery box or container. The conveyor system is arranged to transport a portion of the delivery box or container moving on a backline conveyor passing through a pick station, via a station container through which the goods ordered by the customer are transferred from the storage box or container to the customer delivery box or container by a worker. When the customer delivery container is located at the picking station (74) of the conveyor system, the customer delivery container stops, and a worker selects the required goods from the storage box or container and places them inside the customer delivery box or container. At the known robotic picking station, the storage box or container is lifted from a stack containing the inventory goods required to fulfill the customer order by a load handling device (30). Once lifted by the load handling device (30), the storage box or container is transferred by the load handling device to the output port (42b) above or adjacent to the pick station (74). At the pick station (74), the required stock item(s) can be removed manually or robotically from the storage box or container and placed in a delivery container, which forms part of the customer order and is filled to be delivered in a timely manner.

[0055] The disclosed fulfillment center also includes various other stations, including (but not limited to) charging stations for charging rechargeable batteries that power load handling devices and service stations for performing routine maintenance on load handling devices.

[0056] To accommodate any one or a combination of stations, a separate area (72) is provided adjacent to the grid framework structure (14). Typically, the separate area (72) is provided by incorporating a mezzanine (76) supported by vertical beams (78) between adjacent grid framework structures (14), and is generally a standalone structure. The mezzanine (76) provides a tunnel to accommodate, for example, one or more fix stations and / or any of the stations described above. The area below the mezzanine level is typically served by people working at one or more stations. A grid structure from the adjacent grid framework structure (14) extends across the top of the mezzanine (76) to connect to the grid on both sides of the mezzanine level (76).

[0057] To deliver storage containers to and / or pick up from one or more pick stations below the mezzanine level, a grid structure extending across the mezzanine level includes one or more ports (42b). As taught in the introduction of this patent specification, a port represents a location or grid cell where a load handling device can drop off a storage container and / or pick up a storage container from a pick station below the mezzanine level so that the storage container can be accessed from outside the grid or delivered out of or into the grid framework structure. The grid column where the port is located may be referred to as a “delivery column.” The storage grid includes two delivery columns. The first delivery column may include a dedicated drop-off port where, for example, a container handling vehicle can drop off a storage container to be transported to an access station or delivery station through the delivery column, and the second delivery column may include a dedicated pickup port where a container handling vehicle can pick up a storage container transported through the delivery column from an access or delivery station. The storage containers are supplied into the access station and exit the fix station through the first transfer column and the second transfer column, respectively.

[0058] As is evident from FIG. 15, a portion of the grid framework structure (14) at the top of the mezzanine (76) is shallower than the grid framework structures on either side of the mezzanine (76), that is, it can accommodate only one or two layers of containers in the stack. The grid structure (14b) extending across the mezzanine is supported by vertical upright members (16) mounted on the mezzanine and is shorter than the vertical columns on either side of the mezzanine. The shorter vertical upright members (16) are sized to accommodate only a small number of containers in the stack, for example, the depth of one or more containers, so that the grid structure lies in a substantially horizontal plane when extending across the mezzanine, i.e., the grid level is maintained across the mezzanine level. The mezzanine level (76) is supported by a separate vertical beam (78). The vertical beam (78) supporting the mezzanine (76) is butted against the grid framework structures (14) on either side of the mezzanine (76). A plurality of stacks of storage containers are stored in vertical storage columns on both sides of the mezzanine. A robotic load handling device operating on the grid structure can retrieve storage containers from one or more vertical storage columns and transport the storage containers up to the mezzanine level, where the load handling device can deliver the storage containers to a pick station below the mezzanine level. Consequently, the grid structure can be divided into different areas. To distinguish between the grid structure extending above the mezzanine level and the grid structure extending above the multiple storage columns, the grid structure extending above the mezzanine level may be referred to as the first area of ​​the grid structure, and the grid structure extending above the multiple vertical storage columns on both sides of the mezzanine level may be referred to as the second area of ​​the grid structure.Similarly, to distinguish between a plurality of upright members supporting a first area of ​​a grid structure above a mezzanine level and a plurality of upright members supporting a second area of ​​a grid structure, the plurality of upright members supporting the first area of ​​a grid structure are referred to as a first set of upright members, and the plurality of upright members supporting the second area of ​​a grid structure are referred to as a second set of upright members. Since storage containers are stored in a plurality of stacks under the grid structure of the second area, the second set of upright members constituting the vertical storage column is longer than the first set of upright members supporting the first area of ​​a grid structure above a mezzanine level.

[0059] An exploded view of one section of a grid framework structure in the joint area (84) between the mezzanine level and the vertical storage column is shown in FIG. 16, and a plan view of the grid structure highlighting the first and second areas of the grid structure is shown in FIG. 17. The joint area (84) shows the difference in length between the upright members (16, 16b) supporting the first area (80) and the second area (82) of the grid structure (14). The shorter upright members (16b) (referred to as the first set of upright members) are positioned to extend over the mezzanine level (not shown), and the second set of upright members are positioned to form a plurality of vertical storage columns (44) for storing storage containers in a stack. Due to the length of the upright members (16) constituting the vertical storage column (44) compared to the length of the upright members (16b) extending above the mezzanine level, the longer second set of upright members (16) is more sensitive to movement than the shorter first set of upright members. During ground movement, particularly during an earthquake, the longer second set of upright members (16b) will vibrate with a greater amplitude than the shorter first set of upright members (16a). The vibration of the grid framework structure containing the vertical storage column (44) is aggravated by the stack of storage containers stored in the vertical storage column. The bending moment generated in the second region (82) of the grid structure as a result of the vibration of the longer second set of upright members (16b) is transmitted to the first region (80) of the grid structure extending above the mezzanine area. The greater the amplitude of the vibration of the second set of upright members, the greater the risk of damage to the interconnection of the grid members where the grid members intersect at the node of the first region (80) of the grid structure (14b).Since the upright member is connected to the grid member by a connecting plate or cap plate at the node of the grid structure by one or more fasteners as described above, the connection between the grid member and the node becomes loose and, in the worst case, breaks, there is a risk that the components of the grid structure, particularly in the first area (80) above the mezzanine area, will detach and fall into the service area. Because people work in that service area, there is a risk that a person working in the service area below will be injured due to the breakage of the connection connecting the grid member to the upright member of the first area (the first set of upright members).

[0060] mechanical fuse

[0061] The present invention alleviates the above problem by creating a weak point in the grid structure that breaks preferentially to separate different regions of the grid structure and prevent the bending moment of one region of the grid structure from being transmitted to another region of the grid structure. In a specific embodiment shown in FIG. 16 and in the plan view of FIG. 17, the weak point (86) is preferentially located in the joint region (84) where different regions of the grid structure meet, that is, between the first region (80) and the second region (82). The weak point (86) is configured to break preferentially when the tensile force acting on the weak point in a predetermined direction exceeds or equals a predetermined load, but other connections of the grid member in the grid structure, such as the connection (52) between the upright member and the grid member through the cap plate (58), are not necessarily broken. In other words, the weak point is configured to break under the applied load, but the connection between the upright member and the grid member is not necessarily broken. The predetermined direction is parallel to the longitudinal direction of the grid member (18, 20) in the joint area (84) between the first area (80) and the second area (82) of the grid structure (14b), which is illustrated by an arrow in FIG. 17. This may follow the X direction or the Y direction depending on the orientation of the grid member in the grid structure. In order to preferentially create a weak point in the grid structure, the predetermined load required to break that weak point must be smaller than that of other connections of the grid member in the grid structure. Other connections are, namely, the connection (52) between the upright member and the grid member as discussed above through the cap plate (158).

[0062] In a specific embodiment of the invention illustrated in FIG. 18, a weak point of the grid structure is provided by a bridging joint assembly (88) comprising a mechanical fuse (90) configured to break when the applied load exceeds or equals a predetermined load. The bridging joint assembly (88) is positioned as one or more connections between a first area of ​​the grid structure and a second area of ​​the grid structure (see FIG. 19). Since the wheel assembly of the robotic load handling device includes a pair of wheels at the front and rear of the vehicle body and a pair of wheels on both sides of the vehicle body (see FIG. 4), the bridging joint assembly (88) is positioned as one or more pairs of connections between the first area and the second area of ​​the grid structure, that is, between a first set of grid members and a second set of grid members. An example of a bridging joint assembly (88) according to the invention is illustrated in FIG. 18. The bridging joint assembly (88) of the example illustrated in FIG. 18 includes a bracket (92) configured to connect the free ends of adjacent grid members (18, 20). The other end of each adjacent grid member is connected to each cap plate (158) by one or more bolts as illustrated in FIG. 18 for connection to an adjacent upright member of the grid structure. The adjacent grid members connected together by the bridging joint assembly (88) function as a single elongated grid element extending between adjacent upright members in the grid structure.

[0063] Tracks (22a, 22b) are positioned on each of adjacent grid members such that when the ends of adjacent grid members are connected together by the bridging joint assembly of the present invention, a continuous track surface extends across the ends of adjacent grid members (see FIG. 19). This is to enable the wheel assembly of a robotic load handling device to move across the bridging joint assembly of the present invention. In a specific embodiment of the present invention illustrated in FIG. 18, the grid member functions as a track support, and a separate track element is mounted to the track support, for example, by a snap-fit ​​arrangement.

[0064] A bracket (92) connecting the ends of adjacent grid members is in the form of a plate that overlaps the ends of adjacent grid members. In a specific example shown in the cross-sectional view of the cross-linked joint assembly illustrated in FIG. 20, two brackets are shown on both sides of the ends of the grid members to clamp the ends of adjacent grid members together. The mutually opposing or free ends of the brackets are connected to the ends of adjacent grid members in a joint area by one or more fasteners, such as bolts, screws, or pins, which are received in an opening in the ends of the grid members, and in the joint area, the ends of the brackets overlap with the ends of the adjacent grid members. One or more fasteners are positioned to break when the applied load exceeds or equals a predetermined load, thereby separating the ends of the adjacent grid members and thus preferentially separating different regions of the grid structure (see FIG. 21). In a specific example illustrated in FIG. 20, the mechanical fuse (90) comprises a shear pin (94) having a breaking region (96), the breaking region comprising a cross-sectional reduction region or neck portion of the pin arranged to be sheared when a load applied to the breaking region exceeds or equals a predetermined load. In a specific example illustrated in FIG. 20, the mechanical fuse comprises two shear pins (94) connected together by a link (98), so that when the pins break, the link holds the shear pins together.

[0065] To prevent other connections of the grid structure, such as the interconnection between the upright member and the grid member, from loosening under a predetermined load, the predetermined load that breaks the mechanical fuse is set to be less than the load of the interconnection between the multiple upright members and the grid member in the grid framework structure. When the grid framework structure vibrates as a result of ground movement, a tensile force is generated in the bridge joint assembly connecting different regions of the grid structure together. If the tensile force exceeds or is equal to the predetermined load and applies a load to the bridge joint assembly that breaks the shear pin, at least one end of the bracket (92) is separated from the connecting end of the grid member, that is, the tensile force is less than the load that holds the grid member together with the upright member in the grid structure. This is illustrated in the schematic diagram in FIG. 21 showing the separation of the ends of the grid members (18, 20). The mechanical fuse (90) may include one or more shear pins for connecting the bracket (92) to the end of the grid member. In a specific embodiment illustrated in FIG. 18, at least two fasteners at each end of the bracket are used to connect the bracket to the end of the grid member. Thus, to separate the end of the grid member, at least two of the fasteners are sheared under a predetermined load to separate the bracket from at least one end of the grid member.

[0066] A mechanical fuse (90) comprising one or more shear pins is positioned to connect a bracket to the end of an adjacent grid member, but other means providing a preferential weak point including a mechanical fuse in the grid structure are equally applicable in the present invention. For example, one or more fasteners used to connect an upright member to a grid member via a connecting plate or a cap plate may function as mechanical fuses. For example, a fracture zone may be created in one or more bolts connecting the grid member to the connecting portion (60) of the cap plate (158), and the fracture zone is positioned so that when a predetermined load is exceeded or such a load is applied, it shears, causing the grid member to be separated from the connecting portion and thus the cap plate (see FIG. 9). In a specific example of the present invention illustrated in FIG. 18, at least two fasteners (100) are used to connect the end of the grid member to the cap plate. These two fasteners may be made as mechanical fuses positioned to shear when the load exceeds or equals a predetermined load. Other means of incorporating a weak point containing a mechanical fuse into a grid structure may include creating a grid member having a fracture zone, e.g., a cross-sectional reduction zone, so that when the tensile force exceeds or equals a predetermined load, a portion of the grid member will fracture. Likewise, the bracket itself connecting the ends of adjacent grid members may include a fracture zone configured to fracture when a predetermined load is exceeded or such a load is applied. In all other examples, the weak point containing the mechanical fuse is configured to preferentially separate different regions of the grid structure during ground movement, e.g., during an earthquake.

[0067] Although mechanical fuses are configured to preferentially isolate different regions of the grid structure, movement of the grid structure is inevitable during operation of the grid framework structure at the implementation center. For example, temperature changes in the environment where the grid framework structure is located can cause different parts of the grid framework structure to expand and contract as a result of thermal expansion. Without precautions for thermal expansion, as the length of one or more grid members expands or contracts, regions of the grid structure may become distorted or buckled, increasing the risk that one or more robotic load handling devices operating on the grid structure may derail.

[0068] In a specific example illustrated in FIG. 22(a to c), the mutually opposing ends of the bracket (92) of the cross-link joint assembly (88) are connected to the ends of adjacent grid members (18, 20) by a sliding connection. The sliding connection between the bracket (92) and the ends of the grid members comprises one or more sliding members, including bolts or pins, positioned to slide along a slot (102) formed in the ends of the adjacent grid members so that the gap between the ends of the grid members can vary in the longitudinal direction, i.e., in the X or Y direction. The cooperation between the slot (102) and the sliding bolt is clearly shown in FIG. 21. The travel length of the ends of the grid members is determined by the length of the slot (102), and the mutually opposing ends of each slot (102) function as stops to prevent further separation of the ends of the grid members. When one or more bolts extending through the slot reach the end of the travel determined by the length of the slot, further movement of the ends of the grid members is prevented. Each of the one or more bolts extending through the slot includes a slide bearing (104) (see FIG. 21) or alternatively a roller bearing to assist the sliding of the bolt along the slot. The sliding connection of a specific embodiment shown in FIG. 22 (a to c) shows a slot formed at the end of a grid member, but the opposite case is also possible where a slot is formed in a bracket connecting the ends of the grid members together and a bolt that fastens the bracket to the end of the grid member is positioned to slide along the slot within the bracket.

[0069] Different stages of end separation of grid members (18, 20) are shown in FIGS. 22(a to c). FIGS. 22a shows the end of a grid member in a closed configuration, and FIGS. 22b–22c show different stages of end separation of a grid member as an adjacent grid member moves longitudinally to a maximum limit determined by the length of the slot (102). One or more bolts extending through the slot (102) can function as mechanical fuses (94) configured to break when the tensile force acting on the bridge joint assembly to separate different regions of the grid structure exceeds or equals a predetermined load. The length of the slot and the spacing of the adjacent grid member ends accordingly are calculated based on the degree of movement of the grid member due to expansion and contraction of the grid member. Typically, during normal operation, the length of the slot allows the grid member to move in the X or Y direction in a range of about 10 mm to about 180 mm as a result of thermal expansion. If the movement of the grid structure generates a pulling force causing the grid member to move beyond a predetermined length, the end of the slot prevents this additional movement of the grid member. However, if the pulling force on the bridge joint assembly exceeds a predetermined load or is similar, the bolt is configured to break upon reaching the end of each slot (102), so that the end of the grid member breaks and separates different regions of the grid structure. In a specific embodiment of the invention illustrated in FIGS. 21 and 22, the grid member connected by the bracket (92) is an I-beam. The slot (102) is formed at the end of the I-beam in cooperation with a mechanical fuse (94) that fastens the bracket (92) to the end of the grid member.

[0070] To provide a continuous track surface on the grid members (18, 20) as the ends of the grid members are separated, the bridge joint assembly (88) further comprises an expansion joint including a first track element (106) and a second track element (108), and a bridge member (110) extending across the ends of the first and second track elements (106, 108). The first track element (106) is positioned at one end of an adjacent grid member, and the second track element (108) is positioned to overlap with the other end of an adjacent grid member. The bridge member (110) extends across the ends of the first and second track elements (106, 108). Each of the first and second track elements and the bridge member (110) represents at least a portion of a single elongated track element. Accordingly, the first and second track elements and the bridging member each have an interface portion profiled to be joined to form a single elongated track element that provides a continuous track surface.

[0071] The upper surface of the bridge member (110) is profiled so that there is a transition from the first track element to the second track element along the expansion joint. In the specific example illustrated in FIG. 23 (a and b), the profiles of the first and second track elements provide a double track comprising a center ridge and tracks on both sides of the center ridge. The upper profile of the bridge member (110) is represented by two tracks or rolling surfaces (110a, 110b) extending longitudinally across the distal end of the grid member. The track surfaces of the bridge member (110) are positioned to provide rolling surfaces for the wheels of the robotic load handling device. The rolling surfaces of the track surfaces extend across the width of the wheels of the robotic load handling device. The bridge member (110) has a first end (112) fixed to a first track element (106) and a second end (114) that can travel along a groove (116) formed in a second track element (108). For example, the second end (114) of the bridge member (110) includes a sliding anchor (118) that is constrained to move along a guide (116) that includes a groove formed in the second track element, as shown in FIG. 24. FIG. 24 also shows a sliding anchor (118) that extends through a groove in an end grid member (18, 20) that supports the second track element. As the ends of adjacent grid members are separated, the bridge member (110) crosses the gap created between the ends of adjacent grid members. In a specific example illustrated in FIG. 23b, the second end (114) of the bridge member (110) is positioned to overlap with the second track element (108).

[0072] However, other means of connecting the gaps across the first and second track elements are applicable in the present invention as the ends of adjacent grid members are separated to provide a continuous track surface. In the example illustrated in FIG. 25 and the example integrated into the grid structure of FIG. 26, the bridging member (110) may be formed as a protruding male portion (110c) of the first track element that is received in a correspondingly formed recess (108b) in the second track element (108). FIG. 25 shows the bridging member (110) formed integrally with the first track element (106) as a protruding male portion, and the second track element includes a receiving female portion (108b). Compared to the bridge member (110) shown in FIG. 23 (a and b), where the track surface (110a, b) of the bridge member (110) extends across the width of the wheel, in the example shown in FIG. 25, the track surface of the bridge member formed by the protruding male portion (110c) contacts only at least half of the width of the wheel when the wheel traverses the bridge member (110). The remaining half of the width of the wheel does not contact the track surface of the protruding male portion (110c). In a robotic load handling device, derailment is prevented by restraining a pair of wheels on both sides of the vehicle body. This can be demonstrated by the schematic diagram shown in FIG. 27, which shows two robotic load handling devices (30a, 30b) side by side on a track provided by a set of parallel bridge members (110) of the present invention, each bridge member (110) having a center lip or ridge (110d) that restrains only one side of each wheel (34). Since each robotic load handling device includes a pair of wheels (34) located at the front and rear of the vehicle body, restraining only one side of the wheel prevents lateral movement of the robotic load handling device, thereby preventing derailment of the robotic load handling device.In a specific example illustrated in FIG. 27, the outer edge of the wheel of the load handling device is constrained by being butted against the center ridge (110d) of the bridge member (110) as the end of the adjacent grid member is separated.

[0073] Typically, the bridge member (110) is a relatively thin metal strip configured to cross the ends of the first and second track elements (106, 108) as the ends of adjacent grid members are separated to provide a continuous track surface across the ends of the first and second track elements. Given that the weight of a robotic load handling device operating on the track may exceed 100 kg, there is a risk that the bridge member (110) will bend due to the weight of the robotic load handling device moving across the bridge member (110). To prevent the bridge member from bending due to the weight of the robotic load handling device operating on the track, the bridge joint assembly further includes a support member (120) in the middle of the ends of the first and second track elements (106, 108) (see FIG. 25 and 26). The upper portion of the support member (120) is profiled to support the bridge member (110) as the ends of adjacent grid members are separated (see FIG. 25 and 26). In a specific embodiment shown in FIG. 25, the support member (120) is secured to a bracket (92) by one or more bolts connecting the ends of adjacent grid members together. The support member (120) is shown to be secured to the bracket (92) in the middle of the ends of the first and second track elements (106, 108), so that when the ends of the grid members are brought together as shown in FIG. 22a, the ends of adjacent grid members are butted against the support member (120), and this support member functions as a spacer between the ends of adjacent grid members.

[0074] In the specific example illustrated in FIGS. 16 and 17, the same type of grid members constitute the grid structure, and consequently, the interconnection between the uprights and the grid members is provided by the same type of cap plates. That is, the bridge joint assembly of the present invention used to connect different regions of the grid structure comprises the same type of grid members. In this specific example illustrated in FIG. 16, the grid members comprise buttock C-sections having substantially an I-shaped cross-sectional profile. When interconnecting the upright members constituting the vertical storage columns using this type of grid member, it is ensured that the grid framework structure can cope with small changes in ground movement characteristic of Type A or Type B earthquakes, but not with large changes in ground movement characteristic of Type D earthquakes. To accommodate large deflection of the grid framework structure characteristic of Type D earthquakes, the grid members constituting the grid structure need to be more substantial in terms of flexural stiffness.

[0075] In a specific example of the invention illustrated in FIG. 28, the grid members (18, 20) constituting a portion of the grid structure comprise tubular beams (122) having a cross section that primarily includes a hollow center section. Compared to beams of other shapes, using tubular beams (122) to construct the grid members provides greater resistance to bending because the walls of the tubular beams (122) can resist bending in all directions. The tubular cross-sectional profile of the grid members provides resistance to bending moments in multiple directions. To further improve the structural rigidity of the grid members against bending, the wall thickness of the grid members constructed as tubular beams is much greater than the wall thickness of the grid members of the Type A or Type B grid structures described above. Additionally, compared to bolting the grid members at the intersections (which are prone to loosening due to strong earthquakes), the grid members are preferably welded at the intersections (52). The welded joint at the intersection (52) provides a stronger and more rigid joint at the intersection where the grid members intersect. As bending moments are transmitted at the intersection, welding the grid members at the intersection (152) means that the joint can better resist the load at the intersection.

[0076] The grid structure is subdivided into a plurality of partial frames as illustrated in FIGS. 29 and 30, and accordingly, one or more of the partial frames (124) include at least one grid cell (42). The plurality of partial frames (124) are assembled together on-site to construct the grid structure. Ideally, to comply with building codes, individual partial frames are bolted together when assembled on-site. The ends of the grid elements constituting the partial frames include connecting parts (125) arranged to be paired with corresponding connecting parts of adjacent partial frames. These connecting parts (125) include one or more holes for receiving bolts.

[0077] To provide a track or rail for a load handling device to move on the grid, separate track support elements (126a, 126b) are mounted directly to the grid element (122) (see FIG. 31). The track support elements (126a,b) enable the track or rail (128a,b) to be installed on the grid element (122). A plurality of track support elements (126a,b) are distributed on the grid element (122) of a partial frame (124) having a profile formed to accommodate the track. Thus, compared to the grid element of the aforementioned grid framework structure where the track support elements are integrated into the grid element of the grid (the buttock C section has a profile for accommodating the track in a snap-fit ​​arrangement), the track support elements (126a,b) of the seismic grid framework structure are separate from the grid element (122). FIG. 29 shows a plan view of a partial frame (124) according to one embodiment of the present invention, showing that track support elements (126a, 126b) extending in the X and Y directions are directly mounted to a tubular grid element (122), and FIG. 31 shows a cross-sectional view of the partial frame showing that a track (128a, b) is coupled to a grid element (18, 20) by a track support element (126a, 126b) according to one embodiment of the present invention. Similar to the track mounted to the grid element of the grid framework structure discussed above, the track (128a, b) is installed to the grid element (122) of the seismic grid framework structure through the track support elements (126a, b) by a snap fit and / or slide fit arrangement.

[0078] Since the grid elements are welded together at the intersections, the seismic grid framework structure of the present invention eliminates the cap plate for joining the grid elements together. To interconnect vertical upright members to the seismic grid framework structure of the present invention, a spigot (162) for connection to an upright column (16) is mounted directly to the lower side of the partial frame (124) at the joint where the grid members intersect (see FIG. 30). In a specific embodiment of the present invention, the spigot (162) is welded to the lower side of the partial frame at the joint where the grid members (18, 20) intersect, i.e., at the node of the grid structure. As shown in FIG. 30, it can be seen that four spigots (162) are mounted directly to the lower side of the partial frame (124) at the intersection where the grid members (18, 20) intersect. However, to increase the structural rigidity of the grid structure, other beams having structural bending resistance may be used. Such beams include, but are not limited to, I-beams.

[0079] A D-shaped grid structure is more suitable when the grid members of the grid structure are subjected to increased bending moments and stresses due to ground movement. Since the grid members above the vertical storage columns are sensitive to increased bending moments due to the height or length of the vertical upright members for storing multiple storage containers in the vertical stack, the grid members constituting the grid structure above the vertical storage columns tend to be composed of beams with greater bending resistance, such as tubular beams as described above. However, other areas of the grid structure, namely the area above the mezzanine level, do not necessarily require the same level of structural rigidity as the grid structure above the vertical storage columns and may be based on beams with less bending resistance, such as buttock C sections as described above. This is exemplified in one section of the grid framework structure shown in FIG. 32, where different areas (80, 82) of the grid structure are composed of different types of grid members (18, 20). However, the problem when different regions (80, 82) of a grid structure have different levels of structural stiffness is that a structurally stiff grid structure may collapse a weaker grid structure or at least cause substantial damage to that weaker grid structure during a strong earthquake, which is characteristic of a D-type earthquake. The bridge joint assembly of the present invention can also connect different regions of a grid structure, and each region of the grid structure includes different types of grid members. In a specific example illustrated in FIG. 32, the bridge joint assembly of the present invention is used to connect a region (82) of a grid structure containing a tubular beam (122) with a region (80) of a grid structure containing a buttock C section. However, the bridge joint assembly (88) of the present invention is not limited to the type of grid member illustrated in FIG. 32 and can be used to connect any type of grid member of different regions of a grid structure together.

[0080] For ease of explanation, a grid structure containing weaker grid members may be named the first region (80) of the grid structure (14b), and a grid structure containing structurally stronger grid members may be named the second region (82) of the grid structure (14b). The grid members constituting the first region (80) of the grid structure may be referred to as first-type grid members and may correspond to the grid members shown in FIG. 10. Likewise, the grid members constituting the second region (82) of the grid structure may be referred to as second-type grid members and may correspond to the grid members shown in FIG. 28. Because the grid members constituting the first and second regions (80, 82) of the grid structure (14b) differ from each other in shape and dimensions, different brackets (158, 130) are required to connect the first and second regions (80, 82) of the grid structure (14b) together, incorporating the cross-linking joint assembly (88) of the present invention. Different brackets (158, 130) connecting the different regions (80, 82) of the grid structure (14b) together are required to ensure that the grid level is maintained horizontally across the different regions of the grid structure. The cross-linking joint assembly (88) is positioned to connect the ends of adjacent grid members extending between the first and second regions of the grid structure, as shown in FIG. 33. The other respective ends of adjacent grid members are connected to their upright members by a first type bracket (158) and a second type bracket (130) to compensate for the height difference between the grid members constituting the first region (80) and the second region (82) of the grid structure. For ease of explanation, adjacent grid members connected together by the cross-linked joint assembly of the present invention to form an elongated grid element may be referred to as the first and second parts of the grid members connecting the first and second regions of the grid structure.Accordingly, a first part of the grid member is connected to an upright member by a first type bracket (158), and a second part of the grid member is connected to an adjacent upright member by a second type bracket (130). In the specific example shown in FIG. 33, since the grid member in the first area of ​​the grid structure is generally a buttock C section, i.e., a first type grid member, the first type bracket is a cap plate (158). However, since the grid member in the second area of ​​the grid structure needs to be structurally more resilient to ground movement, the second type bracket (130) includes a pillar or spacer (132), which has an uppermost end (134) connected to the end of the second part of the grid member and a lowermost end (136) connected to an upright member, thus accommodating the height difference of the grid member in the first area of ​​the grid structure and also ensuring that the track is kept horizontal throughout the grid structure. Pillars or spacers (132) compensate for the height difference between the grid structure of the first region and the grid structure of the second region. The grid member in the second region of the grid structure is generally tubular with a hollow cross-sectional profile as shown in FIG. 28, i.e., a grid member of the second type. In all cases, the bridge joint assembly (88) behaves similarly as described above and is configured such that the mechanical fuse is preferentially broken when the pulling force acting on the mechanical fuse exceeds or equals a predetermined load, thereby separating the first region of the grid structure from the second region of the grid structure.

[0081] Bidirectional expansion joint

[0082] An expansion joint comprising a first track element (106), a second track element (108), and a bridge member (110) extending across the ends of the first and second track elements can compensate for movement of the grid member in the longitudinal direction (indicated by an arrow in FIG. 34) and thus can cover movement only in the X or Y direction. To compensate for movement of the grid member in both the X and Y directions, a separate expansion joint would be required to connect the ends of adjacent grid members extending in the X and Y directions to cover movement in both longitudinal directions. In the present invention, to compensate for movement of the grid member in both the X and Y directions, at least one of the upright members is connected to the grid member by a connection part including a pivotable joint, so that the grid member can rotate in the horizontal plane about a vertical axis extending through the pivotable joint. Since the grid member is connected to the upright member by a bracket (in this case, a cap plate (158)), a pivotable connection part exists between the cap plate and the end of the grid member as shown in FIG. 34. As described above, the cap plate (158) is restricted from rotational movement by a spigot (62) that extends downward from the cap plate and is received in a correspondingly formed hollow center section (46) of a vertical upright or upright member (16). A pivotable connection is provided by a bolt or bearing member that extends through an opening (238) in the connection portion of the cap plate (158) as shown in FIG. 38.

[0083] When the grid member moves as a result of expansion and / or contraction of the grid member, the pivotable connection can absorb the movement of the grid member in the X or Y direction. Movement in the longitudinal direction is absorbed by the sliding relationship of the track elements (106, 108) described above. To integrate two movements in the X and Y directions, at least one end of the grid member of the grid structure connected or joined together by the cross-linked joint assembly of the present invention is pivotally connected to its respective upright member.

[0084] To better illustrate the concept of a pivotable joint along with the sliding relationship of a track element covering movement in both X and Y directions, the relationship between the pivotable connection of a grid member and the sliding connection of a track element located on the grid member is best illustrated by reference to a first upright member (16a) and a second upright member (16b) (Fig. 32) interconnected by a grid member extending between two upright members shown in Fig. 34 and 35. In the specific example shown in Fig. 34, the ends of adjacent grid members extending between the first and second upright members are connected together by a cross-joint assembly (88) of the present invention to allow movement of the grid members in the longitudinal direction. The first upright member is connected to the grid member by a connection including a pivotable joint at its normal end, so that when one of the first or second upright members moves relative to the other of the first or second upright members, the grid member can rotate in the horizontal plane about a vertical axis extending through the pivotable joint. In the specific example illustrated in FIG. 34, the end of an adjacent grid member (18, 20) extending between the first and second upright members is pivotally connected to each upright member so that one of the first or second upright members can move relative to the other of the first or second upright members. Rotation of the grid member causes corresponding rotational movement of the track elements (106, 108) located on the grid member, as shown in the schematic diagram of a portion of the grid structure illustrated in FIG. 36 and 37. Thus, when subjected to a force in the X or Y direction, the track (22a, b) can move laterally. In the specific example illustrated in FIG. 36, the track is allowed to move laterally in the horizontal plane in the X direction.

[0085] To accommodate longitudinal movement, a joint between the ends of adjacent grid members, comprising first and second track elements (106, 108) and a bridge member (110) extending across the first and second track elements, allows one end of the bridge member to slide in the longitudinal direction (see FIG. 36) (in this case, the Y direction). Thus, rotational movement of the connected grid members by the pivotable joint allows movement of a portion of the grid structure in the X direction, and the bridge joint assembly connecting the ends of the grid members together allows longitudinal movement in the Y direction, that is, both X and Y direction movements can be covered by a single thermal expansion extending between adjacent vertical or upright members.

[0086] As a result of the pivotable joint connecting the grid member to the upright member, if one of the first or second upright member moves relative to the other of the first or second upright member, the track element is displaced relative to an adjacent track element in the area where the track element intersects at the node (52) of the grid structure. As shown in FIG. 37, due to this displacement, the upper track profile is misaligned, particularly at the node. If the rotation of the grid member, and thus the rotation of the corresponding track, is too excessive and interferes with the continuous track surface in the joint area where the track element meets at the node of the grid structure, the wheel of the robotic load handling device is at risk of derailing when crossing the intersection of the track elements. To prevent excessive misalignment of the track element resulting from the grid member rotating around the pivotable connection with the upright member, the pivot joint is limited to rotate by a predetermined angle from its center or nominal position, and the predetermined angle is sufficiently small to allow the wheel of the robotic load handling device to traverse the misaligned track element. A pivotable joint is restricted to rotate at a predetermined angle by providing a stop member positioned to rotate in an arched slot having a radius of curvature centered on the pivotable joint. In addition to the opening (238) in the connecting portion of the cap plate (158) that accommodates the pivotable joint between the end of the grid member and the cap plate as shown in FIG. 38, the connecting portion of the cap plate (158) further comprises at least one arched slot (140), and a stop member (142) (see FIG. 35) extends through the arched slot so that the grid member connected to the cap plate (158) by the pivotable joint can rotate at a predetermined angle defined by the arc of the arched slot (140). In a specific embodiment shown in FIG. 42 (a and b), the stop member (142) comprises a shear pin (146) having a fracture area (96).The predetermined angle may be in the range of 1° to 20°, preferably in the range of 5° to 20°. During operation, the stop member (142) received within the arched slot (140) is positioned to be guided by the arched slot (140) to a limit determined by the end of the arched slot (140). When the stop member (142) is brought into contact with the mutually opposite ends of the arched slot (140), further rotation of the grid member is prevented. In a specific embodiment illustrated in FIG. 38, two arched slots (140) appear in the connecting portion of the cap plate / bracket positioned on both sides of the pivotable joint, that is, as mutually opposite arched slots (140). Each arched slot (140) has a radius of curvature centered on the pivotable joint and defines an arc in which the stop member (142) is received.

[0087] A pivotable connection between a grid member and an upright member is not limited to a first type bracket including a cap plate (158) as shown in FIG. 38, but may also be provided between a connection of a second type bracket (130) and the D-shaped grid member (i.e., second type grid member) discussed above (see FIG. 33 and 39). Here, the uppermost connection (134) of the second type bracket (130) includes an opening (338) for receiving a pivotable joint and an arched slot (240) having a radius of curvature centered on the pivotable joint. The lowermost connection (136) of the second type bracket (130) is fixed to an upright member. Using the terminology discussed with reference to FIG. 34 and 35, the lowermost connection (136) of the second type bracket (130) is fixed to a second upright member (16b). In a specific example of the invention illustrated in FIG. 32, the first upright member (16a) is shorter than the second upright member (16b). Consequently, ground movement, for example during an earthquake, tends to cause the longer second upright member (16b) to vibrate with a greater amplitude than the shorter first upright member (16a). As previously mentioned, to compensate for the difference in vibration amplitude between the first upright member (16a) and the second upright member (16b), a D-shaped grid member or a second type of grid member interconnecting the second upright member (16b) in a second region of the grid structure is configured to provide greater structural integrity or stiffness than the first type of grid member during ground movement. Consequently, the cross-sectional profile of the second type of grid member is of a different size than the cross-sectional profile of the first type of grid member, for example, being larger.The second type bracket (130) compensates for the size difference between the first type grid member and the second type grid member, so that when the first area of ​​the grid structure containing the first type grid member is connected to or joined to the second area of ​​the grid structure containing the second type grid member, the grid structure is maintained substantially horizontal.

[0088] By adjusting the type of bracket used to connect the upright member to the grid member in the grid framework structure, the first upright member can be laterally displaced relative to the second upright member by a pivotable connection between the grid member and its respective upright member, regardless of the type of bracket used to connect the grid member to the upright member (see FIG. 40 and 41). Thus, expansion and contraction of the grid member in the longitudinal direction are provided by the movement of the first track element (106) relative to the second track element (108). The bracket (92) maintains the connection between the ends of the grid member supporting the first and second track elements (106, 108). Movement perpendicular to the longitudinal direction is provided by the rotation of the grid member (18, 20) relative to the connected upright member through the second type of bracket (130).

[0089] When the force rotating the grid member exceeds a predetermined load characteristic of an earthquake, the stop member (142) may function as a mechanical fuse, which is positioned to break when a load applied in a first direction or a second direction generates a rotational force exceeding the breaking point of the mechanical fuse. An example of a stop member (142) including a breaking area (96) is shown in FIG. 42(a and b), where FIG. 42a shows a stop member (142) in an intact state and FIG. 42b shows a stop member (142) in a broken state, allowing the grid member to rotate over an arc defined by an arched slot. FIG. 42(a and b) also shows optional links (144) of the stop member on both sides of a pivotable joint so that shear pins (146) can move together in each arched slot (240) (see FIG. 39). A cross-section along line XX of FIG. 40 of a pivotable connection between a grid member and an upright member, comprising a stop member (142) accommodated within each arched slot (240) on both sides of the pivotable joint, is shown in FIG. 43 and 44. When the rotation angle of the grid member exceeds a predetermined angle determined by the arc of the arched slot (240) as a result of a force applied substantially perpendicular to the longitudinal direction of the grid member, the mechanical fuse (94) of the stop member (142) breaks, allowing the grid member to rotate further to compensate for the movement of the grid member. This is demonstrated in the cross-section of the pivotable connection between the upright member and the grid member (18, 20) shown in FIG. 44. To compensate for the effects of external forces that distort the grid structure and cause damage to the grid member and the track, the mechanical fuse (94) connecting the grid member to the upright member breaks first, allowing the grid member to rotate.That is, the mechanical fuse (94) provides a sacrificial element to the grid structure that is preferentially broken to prevent or mitigate significant distortion of the grid structure. If one or more interconnections of the upright members to the grid members include pivotable joints, the mechanical fuse allows the first region of the grid structure to move relative to the second region of the grid structure around one or more pivotable connections. The effect of rotation of adjacent grid members between the first and second regions of the grid structure due to the breaking of the mechanical fuse is shown in the schematic diagram in FIG. 45. Here, the track elements (106, 108) of the bridge joint assembly (88) are forced to rotate beyond a predetermined angle, resulting in a large misalignment of the upper profile of the track elements and the adjacent track at the nodes of the grid structure. In the example shown in FIG. 45, misalignment of the track elements (106, 108) relative to the tracks (22a, 22b) at the nodes of the grid structure occurs due to the rotational movement of the track elements as a result of the pivotable joints. When a mechanical fuse is broken as a result of ground movement characteristic of an earthquake, different areas of the grid structure are preserved from further damage, thereby preventing the area of ​​the grid structure from being injured as debris falls on people below the grid structure, especially those below the mezzanine level.

[0090] Each track element of the expansion joint has an interface or joining portion that allows the track elements to be connected to each other to form the single elongated track element discussed above, but the expansion joint relies on having a differently formed component for the first track element and the second track element to be joined together. In other words, the interface portion of each track element of the expansion joint has a differently formed joining profile, so that when the differently formed joining profiles are joined at their respective interface portions, a single elongated track element is formed. For example, in an embodiment of the thermal expansion joint shown in FIG. 25, where a bridge member (110) is formed as a protruding male portion (110b) of the first track element that is received in a correspondingly formed recess (108b) in the second track element (108), the first and second track elements need to be differently formed to be connected together to form a single elongated track element.

[0091] In another embodiment of the invention illustrated in FIG. 46, the interface portions (210a, b) of the first and second track elements (206, 208) are formed such that the interface portion (210b) of the second track element (208) is rotated 180° around the vertical axis of the interface portion (210a) of the first track element (206). In other words, the interface portion (210a) of the first track element (206) is a replica of the second track element (210), but is rotated 180° around the vertical axis so that the interface portions (210a, b) of the first and second track elements can be fitted together to complete the double track surface (110a, 110b) as illustrated in FIG. 47 (a to c), that is, to form a single elongated track element extending in the first or second direction. Thus, only a single molded track element is required for both the first and second track elements, and accordingly, the advantage of reduced tooling costs during the fabrication of the thermal expansion joint is obtained. Since the first track element (206) and the second track element (208) correspond to at least a portion of a single elongated track element, the first track element can be defined as a first track element portion and the second track element can be defined as a second track element portion. Accordingly, FIG. 46 shows a first track element portion (206) and a second track element portion (208) connected together at their respective interface portions to form a single elongated track element. In a specific embodiment of the invention illustrated in FIG. 46, the first and second track element portions are substantially identical but are merely rotated 180° around a vertical axis. FIG. 47 (a to c) illustrates the step of combining a first track element portion (206) and a second track element portion (208) to form a single long track element extending in a first direction or a second direction.

[0092] For the purposes of the present invention, a 180° rotation is interpreted as encompassing substantially 180° and depends entirely on the profile of the interface portion of the first and second track elements having a tolerance that allows the first and second track elements to be connected to each other to form a single elongated track element extending in a first direction or a second direction. A track surface is defined as a surface on which the wheels of a load handling device roll. A dual track includes guide surfaces (69a, 69b, 69c) for restraining the wheels of a load handling device on their respective track surfaces. In a specific embodiment of the present invention, the guide surfaces of the dual track include mutually opposing ribs or ridges (69a, 69b) along the longitudinal edge of the track (one rib on one side of the track and another rib on the other side of the track) to guide each wheel on the track or restrain the wheel from lateral movement, and a center rib or ridge (69c) along the edge of the track parallel to the ribs. The center lip or ridge (69c) is at an equal distance from each of the lip or ridge (69a, 69b) at the edge of the track, so that the area between the center lip (69c) and the lip (69a, 69b) at the edge of the track provides two track surfaces (110a, 110b), allowing the wheels of adjacent load handling devices to pass each other in both directions on the same track.

[0093] In a specific embodiment of the present invention, the interface portions (210a, 210b) of each of the first and second track elements (206, 208) include three stepped portions (212a, 212b, 212c) that are connected together when the first and second track elements (206, 208) are joined together, so that the guide surfaces (69a, 69b) and the center guide surface (69c) at the outer edges of each track element are butted against each other and are connected continuously along the first and second track elements (206, 208) as shown in FIG. 47a. A wheel assembly of a load handling device, comprising a pair of wheels at the front and rear portions of the load handling device, can roll over the track surface across the first and second track elements (206, 208). Movement of the track elements due to thermal expansion provided by the sliding connection between the first and second track elements is shown in FIG. 47(b and c). As the first and second track elements are separated, gaps (214a, 214b, 216) are created on the track surface between the first and second track elements (206, 208). The shape of the interface portion of the first and second track elements is such that two gaps (214a, 214b) (a first gap (214a) on the first track surface (110a) and a second gap (214b) on the second track surface (110b)) are staggered along the length of at least a portion of the track, and the first gap (214a) is offset from the second gap (214b) along the length of the track. In addition to the first and second gaps (214a, 214b) on the first and second track surfaces (110a, 110b), the center ridge (69c) is also separated to create a center gap or a third gap (216). As shown in FIGS. 47b and 47c, the sizes of the first gap (214a), the second gap (214b), and the third gap (216) change as the first and second track elements (206, 208) are separated.The interface portions (210a, 210b) of the first and second track elements (206, 208) are configured so that there is no continuous gap extending laterally across the track when the first and second track elements are pulled and separated. This prevents the wheels of the load handling device from falling into the gap as the first and second track elements are separated.

[0094] The staggered arrangement of the first and second gaps (214a, 214b) ensures that a continuous track surface remains where the wheels of the load handling device can move across the expansion joint when the first and second track elements are separated. In other words, the interface portions (210a, 210b) of the first and second track elements (206, 208) remain overlapping in a direction perpendicular to the longitudinal direction of the first and second track elements when the first and second track elements are separated. Thus, the advantage is obtained that the wheels of the load handling device can still move on their respective track surfaces when the first and second track elements are separated. This is illustrated in FIGS. 48 and 49, which show a set of parallel tracks in the form of a single elongated track element, each track of the set of parallel tracks includes the expansion joint of the present invention, allowing pairs of wheels at the front and rear of the load handling device to move on the track. FIG. 49 shows that when the first and second track elements are separated, the wheel is constrained to the track surface by a guide surface as a result of the staggered arrangement of the gap. When the wheel (36) moves on the track surface of the first track element (206), the wheel (36) is constrained by a guide surface (69a) located at the edge of the first track element (206). Additionally, as the first and second track elements are separated, the width of the track surface at the joint area where they interface is reduced—that is, reduced by half—so that only half of the wheel width is supported on the reduced portion of the track surface. When the wheel reaches the end of the track surface of the first track element (206) and approaches the gap (214a) of the track surface, the constraining of the wheel on the track surface changes from being constrained by a guide surface (69a) located at the edge of the track element to being constrained by a center guide surface (69c) as shown in FIG. 49.Similarly, when the first and second track elements are separated, the wheel being constrained by the center guide surface (69c) is switched to being constrained by one of the outer guide surfaces (69a,b).

[0095] In this way, even when the first and second track elements are separated, the wheel is always constrained on the track surface when moving across the first and second track elements (206, 208). Again, the width of the track surface decreases as the wheel of the load handling device moves on the track surface of the second track element, so that when the wheel moves across the gap (214a), only half the width of the wheel is supported by the track surface. When the wheel of the load handling device crosses the gap in the joint area between the first and second track elements, the wheel of the load handling device is supported by the full width of the track surface.

[0096] A similar arrangement for restraining the wheels of a load handling device to their respective track surfaces when the first and second track elements are separated is also shown in FIGS. 24 through 27, wherein the first track element includes a protruding male portion that can be received in the receiving female portion of the second track element. This may not be the case for the embodiment of the track element shown in FIG. 23, in which the bridging member includes a separate bridging member that provides two track surfaces (110a, 110b). As the first and second track elements are separated, the bridging member (110) restrains the wheels to their respective track surfaces very little, thereby increasing the risk that the wheels may derail from the track surfaces when the first and second track elements are separated.

[0097] However, in contrast to the arrangement of the first and second track elements in the embodiments shown in FIGS. 24 through 27, the spacing (214a, 214b) of the track surface is staggered in the longitudinal direction, so that when the first and second expansion joints are arranged parallel, the spacing of the first expansion joint (218a) is always opposite to the entire track surface in the second expansion joint (218b), and the second expansion joint (218b) is parallel to the first expansion joint (218a). The wheel of the load handling device moving across the parallel first and second expansion joints (218a, 218b) will encounter only one spacing at any given time, rather than encountering multiple spacings multiple times as in the embodiments shown in FIGS. 23 and 26. This reduces the amount of the wheel getting caught or bumping against the spacing, and accordingly, reduces the loudness of the thumping sound of the load handling device on the track. When comparing this configuration with the configuration of the expansion joints shown in FIGS. 23 and 26, the front wheel meets two gaps in the first and second expansion joints simultaneously, and the rear wheel meets two gaps simultaneously; consequently, the level of the wheels of the load handling device getting caught or bumped increases, and accordingly, the thumping sound of the load handling device on the track increases. The only case in the embodiment shown in FIG. 48 (a and b) where the front and rear wheels meet multiple gaps simultaneously is the gap (216) created at the center of the track surface of the first and second track elements when each center guide surface (69c) is separated. The most significant advantage of the embodiment shown in FIG. 46 is that a single type of track element can be used for the first and second track elements, thereby reducing the number of different parts required to assemble the grid structure.

[0098] Both track elements are supported at a sliding connection so that the first track element can slide relative to the second track element. There are many examples of sliding connections according to the present invention. In the first example shown in FIG. 50, the sliding connection (220) is similar to the track support element (56) described above with reference to FIG. 10, but includes back-to-back C sections (222, 224) arranged to slide relative to each other in the joint area where the track elements overlap. The sliding connection in the joint area where the track elements overlap is provided by a slot (226) and a slide bearing (228) device, wherein one end of the C section includes a slot that works in cooperation with the slide bearing connecting the C sections together. In another example shown in FIG. 51, the sliding connection supporting the first and second track elements (206, 208) includes a plate or bar (230). Both the first and second track elements (206, 208) have an opening or recess (232) for receiving an end of the plate (230) at the sliding connection. In a specific embodiment shown in FIG. 51, the first and second track elements (206, 208) are box sections for receiving an end of the plate (230). One end of the plate is secured to the first track element as shown in FIG. 51 using a suitable fastener (234) (e.g., bolt, screw, pin), and the second end of the plate can be received in the recess or opening (232) of the second track element (208). When received in the respective recesses in the first and second track elements, the surface of the plate prevents the upper track profile of the first and second track elements from buckling under the weight of the load handling device moving on the track elements.

[0099] As with other embodiments discussed above, the expansion joint in the embodiment discussed with reference to FIGS. 46 through 51 may form part of a bridge joint assembly for connecting different regions of the grid structure as discussed above. A cap plate (158) for interconnecting adjacent upright members by a track support element supporting the first and second track elements is shown in FIG. 50. Here, the end of the track support element is connected to each cap plate used for fixing to the upright member. Additionally, the track support can be connected to the upright member through the cap plate using a mechanical fuse. If the track support element is a butt C section as shown in FIG. 50, the mechanical fuse may be integrated into a slide bearing in the joint area where the butt C sections overlap. Alternatively, the mechanical fuse may be integrated into a fastener used to connect one of the track support elements to its respective cap plate.

[0100] Various variations of exemplary embodiments apparent to those skilled in the art within the scope of the invention as defined in the claims are considered to be within the scope of the invention. For example, a combination of mechanical fuses may be used to connect at least one of a plurality of upright members to a grid member through a cap plate, together with a mechanical fuse used to connect the ends of adjacent grid members through a cross-linked joint assembly.

Claims

Claim 1 A grid framework structure for supporting a load handling device operated to move one or more containers, wherein the grid framework structure comprises a plurality of upright members arranged to form a plurality of vertical positions for one or more containers to be guided by upright members in a vertical direction, wherein the plurality of upright members are interconnected to define a node at a normal end by a plurality of grid members arranged in a grid pattern comprising a first set of grid members extending in a first direction and a second set of grid members extending in a second direction, wherein the second set of grid members is transverse to the first set of grid members in a substantially horizontal plane to form a grid structure comprising a plurality of grid cells, wherein the grid structure comprises a track system positioned on the plurality of grid members, wherein the track system comprises a plurality of tracks arranged in the grid pattern, wherein the plurality of upright members comprises a first upright member and a second upright member, and these upright members are interconnected by at least one of a plurality of grid members extending between the first upright member and the second upright member, and the first upright A member is interconnected by at least one of the plurality of grid members by a connecting portion comprising a pivotable joint at its normal end, so that when one of the first or second upright members moves relative to the other of the first or second upright members, at least one of the plurality of grid members is rotatable in a horizontal plane about a vertical axis extending through the pivotable joint, and the connecting portion further comprises at least one arched slot through which a stationary member passes and extends, and the arched slot has a radius of curvature centered on the pivotable joint.Therefore, a grid framework structure in which at least one of the plurality of grid members is rotatable about the pivotable joint at a predetermined angle defined by the arc of the arched slot. Claim 2 A grid framework structure according to claim 1, wherein the stopping member comprises a mechanical fuse arranged to break when a load applied in a first direction or a second direction exceeds or equals a predetermined load. Claim 3 In claim 2, the mechanical fuse is a grid framework structure comprising a shear pin. Claim 4 A grid framework structure according to claim 1, wherein the connecting member includes a bracket, the bracket having a first end fixedly connected to the normal end of the first upright member and a second end pivotally connected to at least one of the plurality of upright members by the pivotable joint. Claim 5 In claim 4, the first end of the bracket comprises a spigot positioned to be fixed to the top end of the first upright member, and the second end comprises at least three connecting portions substantially perpendicular to each other, each of the at least three connecting portions being connected to an individual grid member of the grid structure, at least one of the individual grid members being connected to at least one of the at least three connecting portions by the pivotable joint, so that at least one of the individual grid members is rotatable in the horizontal plane about a vertical axis defined by the pivotable joint, a grid framework structure. Claim 6 In claim 5, at least one of the plurality of grid members extending between the first upright member and the second upright member is connected to the second upright member by a second type bracket, the bracket defines a first type bracket, and the second type bracket is different from the first type bracket, a grid framework structure. Claim 7 In claim 6, the plurality of grid members comprises a plurality of first-type grid members arranged in the grid pattern to define a first area of ​​the grid structure and a plurality of second-type grid members arranged in the grid pattern to define a second area of ​​the grid structure, such that at least one of the plurality of first-type grid members is interconnected to a first upright member in the first area of ​​the grid structure and at least one of the plurality of second-type grid members is interconnected to a second upright member in the second area of ​​the grid structure, and the plurality of first-type grid members are different from the plurality of second-type grid members, a grid framework structure. Claim 8 In claim 7, the cross-sectional profile of each of the first type grid members is substantially I-shaped, and each of the second type grid members includes a hollow portion, forming a grid framework structure. Claim 9 A grid framework structure according to claim 1, wherein at least one of the plurality of grid members interconnecting the first and second upright members comprises an expansion joint, the expansion joint further comprises a first track element and a second track element, and a bridge member extends across the ends of the first and second track elements to provide a continuous track surface extending longitudinally in a first or second direction across the ends of the first and second track elements, wherein the bridge member has a first end attached to the first track element and a second end movable longitudinally with respect to the second track element. Claim 10 In claim 9, a grid framework structure wherein the second end of the cross-linking member is configured to be received in a correspondingly formed receiving recess in the second track element. Claim 11 In claim 9, a grid framework structure wherein the second end of the bridge member is positioned to overlap with the second track element. Claim 12 In claim 9, the grid framework structure further comprises a guide member constrained to slide along a groove in the second track element. Claim 13 In claim 9, the grid framework structure further comprises an expansion joint that includes a support member disposed to support the bridge member in a joint area between the end of a first track element and the end of a second track element. Claim 14 A storage and retrieval system comprising: i) a grid framework structure according to any one of claims 1 to 13; ii) a plurality of stacks of containers arranged in storage columns located below the grid, each storage column being located vertically below the grid cell; and iii) a plurality of load handling devices for lifting and moving containers stacked in the stacks, wherein the plurality of load handling devices are operated remotely to move laterally on the grid above the storage columns to access the containers through the grid cells, and each of the plurality of load handling devices comprises: a) a wheel assembly for guiding the load handling device on the grid; b) a container receiving space located above the grid; and c) a lifting device arranged to lift a single container from the stack into the container receiving space. Claim 15 delete

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