Grid Framework Structure

Abstract

1. An expansion joint for connecting areas of a grid structure comprising a plurality of tracks, the second set of parallel tracks extending in a first direction and a second set of parallel tracks extending in a second direction, the second set of parallel tracks passing substantially transversely to the first set of tracks in a substantially horizontal plane such that the plurality of tracks are arranged in a grid pattern comprising a plurality of grid cells, each of the plurality of tracks having an upper surface contoured to provide two parallel track surfaces defining a dual track for guiding two wheeled load handling devices, the expansion joint comprising a first track element (206) and a second track element (208), each of the first and second track elements being connected to the plurality of tracks. the first and second track elements being elongated, each of the first and second track elements having interface portions (210a, 210b) arranged to slide longitudinally relative to one another to provide a dual track with two parallel track surfaces (110a, 110b) extending from the first track element (206) to the second track element (208) suitable for guiding two wheeled load handling devices across the expansion joint, wherein the interface portion (210b) of the second track element (208) is arranged to be substantially 180° rotated about a vertical axis of the interface portion (210a) of the first track element (206).

Description

Technical Field

[0001] The present invention relates to the field of remotely operated load handling devices on tracks positioned on a grid framework structure for handling storage containers or bins stacked within the grid framework structure, and more particularly to a grid framework structure for supporting remotely operated load handling devices.

Background Art

[0002] A storage system 1 with a three-dimensional storage grid structure in which storage containers / bins are stacked on top of each other inside is well known. International Publication No. 2015 / 185628 A (Ocado) of the PCT Gazette describes a known storage and fulfillment system in which stacks of bins or containers are arranged within a grid framework structure. The bins or containers are accessed by a remotely operable load handling device on a track positioned above the grid framework structure. This type of system is schematically shown in FIGS. 1 to 3 of the attached drawings.

[0003] As shown in FIGS. 1 and 2, stackable containers known as bins or containers 10 are stacked on top of each other to form a stack 12. The stack 12 is arranged within a grid framework structure 14 in a warehouse operation environment or a manufacturing environment. The grid framework is composed of a plurality of storage columns or grid columns. Each grid within the grid framework structure has at least one grid column for storing a stack of containers. FIG. 1 is a schematic perspective view of the grid framework structure 14, and FIG. 2 is a top view showing the stack 12 of bins 10 arranged within the framework structure 14. Each bin 10 typically holds a plurality of product items (not shown), and the product items within the bin 10 may be the same or of different product types depending on the application.

[0004] The grid framework structure 14 comprises a plurality of upright members or upright columns 16 supporting horizontal members 18, 20. Each of the plurality of upright members has a cross-sectional profile comprising a hollow central section and four corner sections, each of the four corner sections comprising two vertical guide plates extending along the longitudinal length of the upright member, which cooperate with the corners of the storage containers when the storage containers are guided along the upright member. The hollow central section is preferably a box section.

[0005] Multiple upright columns are interconnected at their upper ends by a first set of parallel grid members 18 extending in a first direction and a second set of grid members 20 extending in a second direction. The first set of parallel horizontal grid members 18 is positioned perpendicular to the second set of parallel horizontal grid members 20 to form a grid structure or grid 14b located in a horizontal plane supported by the upright members 16, comprising multiple grid cells 15. For the purposes of describing the present invention, intersections where grid members meet or cross within the grid structure constitute nodes of the grid structure. Typically, connecting plates may be used to link or join grid members to upright members at intersections. For example, a connecting plate may be cruciform in shape with four connecting portions for connecting to the ends of adjacent grid members within the grid structure. However, other means exist for interconnecting multiple grid members to multiple upright members within a grid structure, other than the use of cap plates. International Publication No. 2018146304 (Autostore Tech AS) teaches a rail arrangement for wheeled vehicles 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, where the second set is positioned perpendicular to the first set and intersects with the first set, thus forming a grid of parallel rails. The rails comprise a plurality of elongated elements having outer and central ridges defining a double track, the elongated elements further comprising intermediate ridgeless sections, and intersecting elements in the X and Y directions are arranged to overlap in their respective ridgeless sections, thus defining a ridgeless intersection.

[0006] The upright members 16 and grid members 18, 20 are typically manufactured from metal and are typically welded or bolted to each other, or a combination of both. The bins 10 are stacked between the members 16, 18, 20 of the grid framework structure 14 so that the grid framework structure 14 prevents horizontal movement of the stack 12 of bins 10 and guides the vertical movement of the bins 10.

[0007] The upper 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 can be integrated within the grid members, or alternatively, the track system can be formed as separate parts for multiple grid members, in which case the grid members function to support the track system. Referring further to Figure 3, the rails 22 support multiple load handling devices 30 to form a storage and retrieval system 1. A first set 22a of parallel rails 22 guides the movement of robotic load handling devices 30 in a first direction (e.g., the X direction) across the top of the grid framework structure 14, and a second set 22b of parallel rails 22, positioned perpendicular to the first set 22a, guides the movement of load handling devices 30 in a second direction (e.g., the Y direction) which is perpendicular to the first direction. In this way, the rail 22 allows the two-dimensional lateral movement of the robotic cargo handling device 30 in the horizontal XY plane so that the cargo handling device 30 can be moved to a suitable position above any of the stacks 12.

[0008] Rails or tracks typically comprise elongated elements contoured to guide load handling devices on a grid structure, and are typically contoured to provide a single track surface to allow a single load handling device to move along the track, or a double track surface to allow two load handling devices to pass each other on the same track. When the elongated element is contoured to provide a single track, the track comprises opposing lips along the length of the track (one lip on one side of the track and the other lip on the other side of the track) to guide each wheel on the track or to restrict its lateral movement. When the contour of the elongated element is a double track, the track comprises 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 typically comprises a central ridge or lip and lips on either side of the central ridge. In all cases, the wheels of a load handling device are constrained on either side or both sides of the wheels of the load handling device when traversing the grid structure. To prevent the wheels of the cargo handling device from derailing, the tolerances between adjacent track elements in the grid structure are very small. To accommodate track movement caused by temperature differences that can cause the track to expand and contract, resulting in buckling or tension within the rail, one or more thermal expansion joints are incorporated into the track system to connect areas of the track system to provide some relief from the resulting movement of the track area.

[0009] International Publication No. 20200774257 (Autostore Technology AS) relates to an expansion joint for connecting areas of a rail-based grid storage system, the expansion joint comprising a first rail element and a second rail element, the rail elements being elongated and configured to slide longitudinally relative to one another within an overlapping joint area, the expansion joint having a contoured upper surface defining one or more tracks for supporting a container handling vehicle, the tracks extending from the first rail element through the joint area to the second rail element, within the joint area each rail element providing its track or a portion of each track on its contoured upper surface, thereby creating a transition section that extends along the expansion joint from the first rail element to the second rail element of its track or each track.

[0010] A known load handling device 30, shown in Figures 4 and 5, comprises a vehicle body 32 described in International Publication No. 2015 / 019055 (Ocado) of the PCT Patent Publications, which is incorporated herein by reference, where each load handling device 30 covers only one grid space of a grid framework structure 14. Here, the load handling device 30 comprises a wheel assembly comprising a first set of wheels 34, consisting of a pair of front wheels 34 of the vehicle body 32 and a pair of rear wheels 34 of the vehicle body 32 for engaging with a first set of rails or tracks to guide the movement of the device in a first direction, and a second set of wheels 36, consisting of a pair of wheels 36 on each side of the vehicle 32 for engaging with a second set of rails or tracks to guide the movement of the device in a second direction. Each set of wheels is driven to allow the vehicle to move along the rails in the X and Y directions, respectively. One or both sets of wheels are vertically movable to lift each set of wheels away from their respective rails, thereby allowing the vehicle to move in the desired direction.

[0011] The cargo handling device 30 is equipped with a lifting device or crane mechanism for lifting storage containers from above. The crane mechanism comprises a winch tether or cable 38 wound around a spool or reel (not shown) and a gripping device 39. The lifting device comprises a set of lifting tethers 38 that extend vertically and are connected near or there to the four corners of the lifting frame 39, which are also known in other words as a gripping device (one tether near each of the four corners of the gripping device) for a releasable connection with the storage container 10. The gripping device 39 is configured to releasably grip the top of the storage container 10 in order to lift the storage container from a stack of containers in a storage system of the type shown in Figures 1 and 2.

[0012] Wheels 34, 36 are positioned around a cavity or recess within the lower section, known as the container receiving space 40. The recess is sized to accommodate the container 10 when it is lifted by the crane mechanism, as shown in Figures 5(a and b). While in the recess, the container is lifted away from the rails below so that the vehicle can move laterally to a different location. Upon reaching the destination, e.g., another stack, an access point in a storage system, or a conveyor belt, the bin or container can be lowered from the container receiving section and released from the gripping device. The container receiving space is not limited to the container receiving space 40 located within the vehicle body 32. The container receiving space can be located below a cantilever, in which case the vehicle body of the cargo handling device has a cantilever structure as described in International Publication No. 2019 / 238702 (Autostore Technology AS). For the purposes of this invention, the term "vehicle body" is interpreted as optionally covering the cantilever such that the gripping device is positioned below the cantilever.

[0013] To access the contents of a storage container, the majority of the grid columns are storage columns, i.e., grid columns in which storage containers are stored within a stack. However, the grid structure typically has at least one grid column not used for storing storage containers, but which includes a location or grid cell 15 from which a cargo handling device can drop off and / or pick up a storage container so that the storage container can be accessed from outside the grid or transported to a second location (not shown in the prior art diagrams) in which it can be transported in or out of the grid. In the art, such a location or grid cell is typically referred to as a “port,” and the grid column in which the port is located may be referred to as a “delivery column.” The storage grid comprises two delivery columns. The first delivery column may include, for example, a dedicated drop-off port, where a container handling vehicle can drop off a storage container that is to be transported further through the delivery column to an access station or transport station, and the second delivery column may include a dedicated pickup port, where a container handling device can pick up a storage container that has been transported through the delivery column from an access or transport station. The storage containers are sent into the access station and exit the access station via the first and second delivery columns, respectively.

[0014] Upon receiving a customer order, a load handling device, capable of moving along a track, is instructed to pick up a storage bin containing the items of that order from a stack within a grid framework structure and transport the storage bin through a delivery column to a pick station, where the items can then be retrieved. Typically, the load handling device transports the storage bin or container to a bin lifting device integrated within the grid framework structure. The mechanism of the bin lifting device lowers the storage bin or container to the pick station. At the pick station, the items are retrieved from the storage bin. Picking can be performed manually or by a robot as taught in UK Patent No. 2524383 (Ocado Innovation Limited). After retrieval from the storage bin, the storage bin is transported to a second bin lifting device, where it is then lifted to a grid level leading to a pickup port for retrieval by the load handling device and transported back to its location within the grid framework structure.

[0015] A separate area is provided adjacent to the storage column to accommodate access stations for cargo handling devices to drop off storage containers to pickup stations or to pick them up from pickup stations. Typically, the separate area is provided by incorporating a mezzanine supported by vertical beams within an adjacent grid framework structure. The mezzanine provides a separate area for accommodating one or more pickup stations. Typically, the separate area is a tunnel with grid framework structures on either side of it. The grid structure from the adjacent grid framework structure extends across the top of the mezzanine to connect to the grid structure on both sides of the mezzanine so that the grid structure is positioned in a substantially horizontal plane. One or more delivery and / or pickup ports are assigned to one or more grid cells of the grid structure extending across the mezzanine so that cargo handling devices operable on the grid structure can drop off storage containers and pick them up from the pickup stations below. As a result of the grid structure extending across the mezzanine, the grid structure above the mezzanine tends to be shallower than the grid framework structures on either side of the mezzanine, meaning that only one or two layers of containers can be accommodated in the stack. The mezzanine is supported by separate vertical beams. The vertical beams supporting the mezzanine abut the grid framework structures on either side of the mezzanine. In addition to one or more picking stations, the separate area created by the mezzanine can accommodate a variety of other stations, including, but is not limited to, charging stations for charging rechargeable batteries that power the cargo handling devices on the grid, and service stations for performing routine maintenance on the cargo handling devices. Because such stations require manual labor, one or more workers tend to be located below the mezzanine. These workers include, but are not limited to, picking workers at picking stations and service workers at work stations.

[0016] Grid framework structures are subject to a variety of external and internal forces. These include, but are not limited to, ground movement that may result from the composition of the ground or soil type, forces generated by the movement of cargo handling devices on the grid framework structure that can weigh more than 100 kg, forces generated by movement resulting from nearby structures or moving vehicles such as trains, or forces that occur during earthquakes or storms. To ensure the stability of grid framework structures, conventional storage and retrieval systems rely heavily on various supports and braces positioned within the grid or at least partially along its perimeter. However, using various supports and braces (anti-movement braces) to stabilize grid framework structures from internal and external forces is disadvantageous for several reasons. This grid framework structure occupies space or area that could be used by the grid for container storage, in that it hinders the optimal use of space or area available for container storage. Any auxiliary grid support structure often requires connection to surrounding structures such as the interior walls of a building, and necessitates cost-inefficient support structure requirements, so the need for support structures can limit the available options for positioning grid framework structures.

[0017] International Publication No. 2019 / 101367 (Autostore Technology AS) teaches a grid support structure for integration into a storage grid structure of a deployed automated storage system. The grid support structure consists of four storage columns interconnected by a plurality of vertically inclined support columns. The storage column contour has a cross section comprising a hollow central section and four corner sections, each corner section comprising two vertical bin guide plates for accommodating the corners of storage bins. The support columns have a width that allows them to fit between two parallel guide plates so as not to impair the storage column's ability to accommodate stacks of containers or storage bins.

[0018] While some movement within the grid framework structure is considered acceptable to provide relief to the orbital system as a result of thermal expansion and contraction, excessive movement of the grid framework structure is not considered acceptable because it may damage the structural fasteners that hold the grid framework structure together.

[0019] A large portion of the world's population lives along earthquake fault lines or in the path of powerful storms such as hurricanes and tornadoes. Positioning grid frame structures within such areas poses a risk of structural damage from earthquakes and storm events, as existing grid framework structures may not hold the grid together. As a result of powerful earthquakes and storm events, for example, structural fasteners may fail to keep the grid securely attached to the upright members, leading to a failure in the structural integrity of the grid framework structure. Earthquakes can be labeled into four categories, A, B, C, or D, depending on their intensity, with Type A being the least powerful and Type D the most powerful. Types A through D can be graded by their spectral acceleration, which is the maximum acceleration, measured in g, experienced by an object above the Earth's surface during an earthquake. Type D is considered to represent the most powerful seismic events, typically having measured spectral accelerations in the range of 0.5g to 1.83g (short-term spectral response acceleration SDS, see https: / / www.fegstructural.com / seismic-design-category-101 / ), and is the cause of most building failures. When a powerful seismic event acts on a structure, the three-dimensional dynamic forces damage the structural fasteners that hold the grid framework structure together, thereby causing the structural fasteners to loosen or detach from the members in which they are embedded, or, if the structural fasteners remain in place, to penetrate the structural components.

[0020] During ground movement resulting from seismic events, grid framework structures tend to vibrate. 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 ground movement, while transverse wave vibrations are perpendicular to the ground movement. In both cases, the amplitude of vibration of the grid framework structure depends very heavily on the degree of ground movement, which in turn depends on the category of the earthquake. For Category D earthquakes, the amplitude of vibration is considerably larger than for Category A earthquakes. Because the upright members of a grid framework structure are interconnected at their upper ends by multiple grid members extending in first and second directions, bending moments can be generated as a result of the movement of the grid framework structure, where the grid members intersect or converge at joints in the vertical upright members. While thermal expansion joints provide some mitigation of track system movement to prevent derailment of cargo handling devices, this is not the case when the track system movement is excessive enough to loosen or, in the worst-case scenario, rupture the structural fasteners at the interconnections, i.e., during seismic events. Not only are the structural fasteners that interconnect the grid members together subjected to bending moments as a result of ground movement, but other structural fasteners that connect the grid members together and / or bracing members supporting the upright members are also subjected to excessive forces. The forces experienced at the interconnections intensify as the height of the grid framework structure increases, as a result of the amplitude of vibrations in the grid framework structure.

[0021] Individual containers may be stacked in vertical layers, and their locations within the grid framework structure or "beehive" may be represented using a three-dimensional coordinate system to indicate the position of the cargo handling device or container and the depth of the container (e.g., (X, Y, Z), container at depth W). Similarly, locations within the grid framework structure may be represented in two dimensions to indicate the position of the cargo handling device or container and the depth of the container (e.g., (X, Y), container at depth W). For example, Z=1 identifies the top layer of the grid, i.e., the layer immediately below the rail system, Z=2 is the second-lowest layer from the rail system, and so on down to the bottom layer of the grid. Given that depth Z can be the same height as 21 levels, and that a typical storage container can be 30-40 cm tall, the amplitude of vibrations in the grid framework structure can become extremely violent during an earthquake.

[0022] Considering a rough example where the vibration of a grid framework structure fixed to the ground is equivalent to the vibration 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]

number

[0024] In the equation, L is the effective height of the grid framework structure, and θ is the angle the grid framework structure makes with respect to the vertical. When θ is expressed in radians, s can be considered to be the amplitude of vibration of the grid framework structure. Therefore, according to equation (1), the higher the height of the grid framework structure, the greater the amplitude of vibration of the grid framework structure during ground movement. As a result of excessive vibration of the grid framework structure due to seismic events, the structural fasteners holding the grid members and / or upright members together may become weak, and in the worst-case scenario, this may cause the grid framework structure to collapse. Given that people work below the grid structure, particularly below the mezzanine level as discussed above, the collapse of the grid framework structure would endanger the lives of people below the mezzanine level. In addition to the division of the area of ​​the grid framework structure, vibration of the grid framework structure also makes it easier for storage containers stacked between the upright members and / or the contents of the storage containers to be thrown out. In order to mitigate the risk of injury to people in the event that the grid framework is disrupted or, in the worst-case scenario, collapses, a grid framework structure that separates areas where people are located is necessary. [Overview of the project]

[0025] A known telescopic joint for providing extension and contraction of grid members / track elements within a grid structure comprises several components of different shapes that need to be assembled together to provide a sliding connection between grid members / track elements. For example, International Publication No. 20200774257 (Autostore Technology AS) relates to a telescopic joint for connecting areas of a rail-based grid storage system, and a telescopic joint for a double rail system comprises a projecting male portion defining a first rail element, which is slidably receivable into a recess that forms a female portion defining a second rail element. The projecting male and female portions cooperate to define a dividing line extending between the first and second rail elements, passing along the center of the track, within the joint area where they overlap. The dividing line ensures that the wheels of a load handling device are constrained on the track surface when traversing across the telescopic joint. The track surface may be defined as a rolling surface on which the wheels of a load handling device travel. Not only is the construction of the telescopic joint taught in International Publication No. 20200774257 (Autostore Technology AS) required different parts, but when the first and second rail elements slide apart, the gaps on both sides of the dividing line create undesirable steps, causing the front and rear wheel pairs of the load handling device to catch on or collide with the edges of the gaps when they intersect with the telescopic joint. The telescopic joint in International Publication No. 20200774257 (Autostore Technology AS) is arranged so that there are no continuous slots or gaps extending laterally across the track when the first and second rail elements are pulled apart, but a step exists on the side, and this step on the side creates an area of ​​the track where the wheels of the load handling device may potentially collide with the edges of the step on the side.

[0026] Therefore, there is a need for a telescopic joint that reduces the possibility of the wheels catching on the edges of the gaps or slots when a part of the telescopic joint slides and separates, and does not require different shaped parts. The present invention provides a telescopic joint for connecting a region of a grid structure comprising a plurality of tracks comprising a first set of parallel tracks extending in a first direction and a second set of parallel tracks extending parallel thereto, wherein the second set of parallel tracks passes substantially transversely to the first set of tracks in a substantially horizontal plane such that the plurality of tracks are arranged in a grid pattern comprising a plurality of grid cells, each of the plurality of tracks having an upper surface contoured to provide two parallel track surfaces defining a double track for guiding two wheeled load handling devices, the telescopic joint comprising a first track element and a second track element, each of the first and second track elements providing a part of one track of the plurality of tracks, the first and second track elements being elongated, each of the first and second track elements having an interface portion arranged to slide longitudinally relative to each other to provide a double track comprising two parallel track surfaces suitable for guiding two wheeled load handling devices from the first track element to the second track element across the telescopic joint, wherein the interface portion of the second track element is arranged to be a 180° rotation about the vertical axis of the interface portion of the first track element, thereby reducing the above problems by providing a telescopic joint.

[0027] Each of the multiple orbitals comprises an elongated orbital element extending in either a first or second direction. More specifically, each of the multiple orbitals is subdivided into multiple elongated orbital elements joined or linked together to form an elongated orbital element extending in either the first or second direction. The first and second orbital elements are arranged to connect together at their respective interface portions to form a single elongated orbital element. In other words, each of the first and second orbital elements corresponds to at least a portion of a single elongated orbital element such that when the first and second orbital elements are connected together at their respective interface portions, a single elongated orbital element is formed. When each of the first and second orbital elements forms a portion of an elongated orbital element, they can be defined as the first orbital element portion and the second orbital element portion. The first and second orbital element portions are configured to connect together to form a single elongated orbital element extending in either the first or second direction.

[0028] Each of the first and second orbital elements has an interface portion contoured to face each other to form a continuous orbital surface. According to the present invention, the interface portion of the second orbital element is positioned to be rotated 180° around the vertical axis of the interface portion of the first orbital element. This makes it possible to use orbital elements molded with the same contour for both the first and second orbital elements, but only by rotating them 180° around the vertical axis.

[0029] By forming the interface portion of the second track element so as to be rotated 180° around the vertical axis of the first track element, the need for differently shaped parts to constitute the extension joint is eliminated. A single body track element can be used for both the first and second track elements by simply rotating one track element 180° around the vertical axis relative to the other track element to connect both track elements to each other, thereby simplifying the manufacturability of the extension joint. To provide the advantage of restraining the wheels of the load handling device onto the track surface, preferably, the upper surfaces of each of the first and second track elements are contoured to provide at least one guide surface of the track, the at least one guide surface being positioned to restrain the wheels of the load handling device onto each of the two parallel track surfaces. Optionally, the at least one guide surface comprises a lip or ridge extending upward from each of the two parallel track surfaces. Preferably, at least one guide surface of the first track element is positioned to abut against at least one guide surface of the second track element in a closed configuration to provide a continuous guide or track surface extending between the first and second track elements, and the first and second track elements are positioned to separate from each other in an open configuration to provide at least one gap within the two parallel track surfaces between the first and second track elements. Preferably, each interface portion of the first and second track elements is formed with three steps configured to fit together in a closed configuration to form a continuous track or guide surface and separate in an open configuration. More preferably, at least one gap comprises two gaps offset from each other in the longitudinal direction. By forming each of the first and second track elements with three steps such that two gaps offset from each other in the longitudinal direction are created when the first and second track elements are separated, the number of steps experienced by the wheels of the load handling device as they move across the telescopic joint of the present invention is reduced.Due to the specific arrangement of the first and second rail elements, when the pairs of wheels before and after the load handling device travel over a parallel set of telescopic joints, the load handling device experiences a gap when traveling over the telescopic joints of the present invention, but only one of the pairs of wheels experiences a gap. This is because the two gaps are longitudinally offset from each other, which is further a result of each interface portion of the first and second track elements being formed with three steps configured to fit together in a closed configuration and separate in an open configuration. In other words, the parallel arrangement of the telescopic joints of the present invention causes gaps to appear successively for one of the pairs of wheels before and after the load handling device and then for the other of the pairs of wheels. In contrast, in the telescopic joints taught in International Publication No. 20200774257 (Autostore Technology AS), both wheels of both pairs of wheels experience a gap at the same time, resulting in a greater impact movement when the load handling device crosses the gap.

[0030] Preferably, at least one guide surface includes a first edge guide surface and a second edge guide surface that run longitudinally along the outer edges of each of the first and second track elements, and a central guide surface that runs parallel to the first and second edge surfaces, whereby the area between the central guide surface and the first and second guide surfaces defines two parallel track surfaces, and the first edge guide surface is longer than the second edge guide surface.

[0031] To support the first and second raceway elements as they slide against each other, the telescopic joint optionally further comprises a sliding connection for supporting the first and second raceway elements to allow them to slide against each other longitudinally. In one example, the sliding connection comprises overlapping raceway support elements arranged to slide against each other. Preferably, the overlapping raceway support elements have slots and sliding bearing arrangements within the joint area where the raceway support elements overlap, so that the sliding bearings are slidably received within the slots. In another example, the sliding connection comprises a connecting element slidably received within openings in the first and second raceway elements. Preferably, the connecting element has a first end fixed within the opening in the first raceway element and an opposing second end arranged to be received within the opening in the second raceway element. Optionally, each of the first and second raceway elements comprises a box section. For example, the connecting element may be a plate or bar that can be received into a recess or opening formed in the first and second raceway elements. One end of the plate is fixed in the first raceway element, and the other end of the plate can be received into a recess in the second raceway element. In either case, the sliding connection is positioned such that the upper raceway contours of the first and second raceway elements are supported by the sliding connection.

[0032] The present invention is a grid framework structure, It comprises multiple upright members, which are arranged to form multiple vertical spaces for one or more containers to be guided vertically by the upright members. Here, a plurality of upright members are interconnected by a plurality of tracks, each comprising a first set of parallel tracks extending in a first direction and a second set of parallel tracks extending in a second direction, such that nodes are defined at their upper ends, and the second set of parallel tracks extends transversely to the first set of tracks in a substantially horizontal plane to form a grid structure comprising a plurality of grid cells for a load handling device, each having a pair of wheels at the front and rear of the load handling device, to move on the grid structure. A portion of the first and / or second set of parallel trajectories comprises first and second telescopic joints, and each of the first and second telescopic joints comprises a telescopic joint according to the present invention. The first and second thermal expansion joints further provide a grid framework structure in which, during use, pairs of front and rear wheels of the load handling device are arranged parallel to each other so as they move across the first and second thermal expansion joints, they are constrained on their respective track surfaces.

[0033] The present invention is a storage and retrieval system, i) The grid framework structure defined above, ii) Multiple stacks of containers arranged within storage columns located below the grid, where each storage column is positioned vertically below the grid cells, iii) Multiple loading / unloading devices for lifting and moving containers stacked within a stack, and the multiple loading / unloading devices are remotely operated to move laterally on a grid above the storage column to access the containers through the grid cells, and each of the multiple loading / unloading devices is a) A wheel assembly for guiding a cargo handling device on a grid, b) Container receiving space located above the grid, c) comprising a lifting device positioned to lift a single container from a stack into a container receiving space, The present invention further provides a storage and retrieval system equipped with the following features.

[0034] Further features and aspects of the present invention will become apparent from the subsequent detailed description of exemplary embodiments made with reference to the drawings. [Brief explanation of the drawing]

[0035] [Figure 1] A schematic diagram of a grid framework structure based on known systems. [Figure 2] A schematic top view showing the stack of bins arranged within the framework structure of Figure 1. [Figure 3] A schematic diagram of a known cargo handling device system operating on a grid framework structure. [Figure 4] A schematic perspective view of a cargo handling device, showing a lifting device that grips a container from above. [Figure 5(a)] A cropped schematic perspective view of the cargo handling device in Figure 4, showing a container housed in the container receiving space of the cargo handling device. [Figure 5(b)] A cropped schematic perspective view of the cargo handling device in Figure 4, showing the container receiving space of the cargo handling device. [Figure 6] A top-down plan view of a section of a grid structure showing adjacent grid cells. [Figure 7] A perspective view showing the arrangement of upright members that form vertical storage columns for stacking containers between them. [Figure 8a] A perspective view of the arrangement of upright members in a grid pattern that forms multiple adjacent vertical storage columns. [Figure 8b] Side view of multiple storage containers stacked within a vertical storage column. [Figure 9] A perspective view showing the arrangement of grid members formed by tracks and track supports, interconnected at nodes or intersections by cap plates. [Figure 10] Perspective view of the orbital support. [Figure 11]A perspective view of a cap plate for interconnecting vertical upright members to grid members at a node. [Figure 12] A perspective view of a cap plate fitted to an upright column to connect adjacent grid members together at an intersection where grid members meet, according to one embodiment of the present invention. [Figure 13] A cross-sectional perspective view of the interconnection between the vertical upright body and the grid member at the node, using a cap plate. [Figure 14] A perspective view of a track or rail. [Figure 15] A schematic diagram of a known fulfillment center showing a mezzanine level between adjacent grid framework structures. [Figure 16] A perspective view of a portion of a grid framework structure within a junction area where a grid structure interconnecting vertical storage columns merges with a grid structure extending on a mezzanine level, according to one embodiment of the present invention. [Figure 17] A top plan perspective view of the grid structure shown in Figure 16, illustrating the linkage of different regions of the grid structure by a bridging joint assembly according to the present invention. [Figure 18] A perspective view of a bridging joint assembly according to the present invention. [Figure 19] A perspective view showing a bridging joint assembly as one or more connection points between different regions of a grid structure according to the present invention. [Figure 20] Cross-sectional view of grid members joined by the bridging joint assembly of the present invention. [Figure 21] A perspective view showing the failure of a mechanical fuse that separates the end of a grid member according to the present invention. [Figure 22(a)] A perspective view showing the steps of separating the grid member from the closed configuration according to the present invention. [Figure 22(b)] A perspective view showing the steps for separating a grid member from a partially open configuration according to the present invention. [Figure 22(c)] A perspective view showing the steps of separating the grid member from the open configuration according to the present invention. [Figure 23(a)] An upper plan perspective view of an expandable joint showing a sliding connection portion of a track element according to the present invention. [Figure 23(b)] A side perspective view of an expandable joint showing a sliding connection portion of a track element according to the present invention. [Figure 24] A perspective view of the sliding connection portion of a track element, showing the anchor fixing of the track element along the runner in a grid member according to the present invention. [Figure 25] A perspective view of another example of a sliding connection for a track element according to the present invention. [Figure 26] A perspective view of an expandable joint according to the present invention, which includes a sliding connection portion for a track element shown in Figure 25 for connecting the ends of grid members. [Figure 27] A schematic diagram of a wheel of a robotic cargo handling device, which is constrained by the track of a sliding connection part, according to the present invention. [Figure 28] A cross-sectional perspective view of an earthquake grid structure showing the cross-sectional contour of a grid member according to one embodiment of the present invention. [Figure 29] A schematic top view of a grid subframe of an earthquake grid framework structure according to an embodiment of the present invention. [Figure 30] A schematic bottom view of a grid subframe of an earthquake grid framework structure according to an embodiment of the present invention. [Figure 31] A cross-sectional view showing the engagement of a grid element of an earthquake grid structure with a track support, according to one embodiment of the present invention. [Figure 32] A perspective view of a portion of the grid framework structure within the junction area between a grid structure extending above the mezzanine level and a seismic grid structure that merges with it, according to one embodiment of the present invention. [Figure 33] Perspective views of different brackets used to connect a bridging joint assembly to different types of grid members of a grid structure, according to the present invention. [Figure 34] An upper plan perspective view of the pivotal connection portion of a grid member with a cap plate for interconnecting upright members according to the present invention. [Figure 35]A side perspective view of a pivotable connection between a grid member and a cap plate according to the present invention. [Figure 36] A perspective view of a section of a trajectory that has shifted position as a result of rotation of a grid member according to the present invention. [Figure 37] An enlarged view of the misaligned trajectory shown in Figure 36, according to the present invention. [Figure 38] A perspective view of a cap plate showing at least one connecting portion having an arch-shaped slot for receiving a stop member according to the present invention. [Figure 39] A perspective view of another example of a second bracket for pivotally connecting a grid member to an upright member according to the present invention. [Figure 40] A perspective view of a rotated grid member between adjacent upright members joined together by the bridging joint assembly of the present invention. [Figure 41] Front view of a pivotable connection of a grid member with a second bracket shown in Figure 39, according to the present invention. [Figure 42(a)] A perspective view of a stop member that functions as a mechanical fuse to control the rotation of a grid member relative to a connecting upright member, showing a stop member in an intact configuration according to the present invention. [Figure 42(b)] A perspective view of a stop member that functions as a mechanical fuse to control the rotation of a grid member relative to a connecting upright member, showing a stop member in a destructive configuration according to the present invention. [Figure 43] A perspective view showing a cross-section of a pivotable joint and a pivotable connection cooperating with a stopper member between a grid member and a second bracket according to the present invention. [Figure 44] A perspective view of the pivotable connection in Figure 43, showing the destruction of a stop member that enables rotation of a grid member relative to an upright member according to the present invention. [Figure 45] A perspective view showing the rotation of a track element relative to other track elements at a point where track elements intersect, exceeding a predetermined angle due to the failure of a stopping member, according to the present invention. [Figure 46]A top view showing the interface portion of the first and second orbital elements according to another embodiment of the present invention. [Figure 47(a)] Top views of the first and second orbital elements in a closed configuration, as shown in Figure 46. [Figure 47(b)] Top views of the first and second orbital elements in a partially open configuration in Figure 46. [Figure 47(c)] Top views of the first and second orbital elements in the open configuration shown in Figure 46. [Figure 48(a)] A top view of the telescopic joint according to the embodiment shown in Figure 46, which is in a closed configuration. [Figure 48(b)] A top view of the telescopic joint according to the embodiment shown in Figure 46, which is in an open configuration. [Figure 49] A perspective view of an extension joint according to an embodiment of Figure 46, showing the wheel of a cargo handling device restrained by a guide surface. [Figure 50] A perspective view of an expandable joint according to the embodiment of Figure 46, showing a track element supported on a sliding connection of back-to-back C-section track supports. [Figure 51] A perspective view of an extension joint according to the embodiment shown in Figure 46, showing the track element as a box section supported on a sliding connection. [Modes for carrying out the invention]

[0036] Grid Framework Structure The present invention was conceived in relation to known features of storage systems, such as grid framework structures and cargo handling devices, as described above with reference to Figures 1 to 5. Figure 6 shows a top view of a section or part of a conventional grid structure 50 having four adjacent grid cells 42, and Figure 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. Figures 8(a and b) show perspective views of upright members arranged to form a vertical storage column 44 for containers 10 to be stored in the vertical storage column 44. Figure 8b shows a vertical stack of containers 10 between the upright members 16.

[0037] Each of the vertical upright members 16 is tubular overall. In the transverse section in the horizontal plane of the storage column 44 shown in Figure 2, each of the vertical upright members 16 comprises a hollow central section 46 (typically a box section), and one or more guides 48 are fitted to or formed at the corners of the hollow central section 46, which extends along the longitudinal length of the vertical upright member 16 to guide the movement of containers along the vertical storage column 44. One or more guides 48 comprises two vertical container guide planes. The two vertical container guide planes are positioned to accommodate the corners of containers or the corners of a stack of containers. In other words, each corner of the hollow central section 46 defines two sides of a substantially triangular area that can accommodate the corners of containers or storage bins. The corners are equally spaced around the hollow central section 46 so that multiple vertical upright members 16 can provide multiple adjacent storage columns, and each vertical upright member 16 may be common to or shared by up to four separate storage columns. Figure 7 also shows that each of the vertical upright units 16 is mounted on an adjustable grid level adjustment mechanism 19, which has a base and threaded shaft that can be extended or retracted to compensate for uneven floor areas at the base of the vertical upright unit.

[0038] The transverse section of the storage column 44 in the horizontal plane of Figure 2 shows that each storage column 44 consists of four vertical upright members 16 positioned at the corners of the containers or storage bins 10. The storage column 44 corresponds to a single grid cell. The cross section of the vertical upright members 16 is constant along the entire length of the vertical upright members. The periphery of the multiple containers or storage bins in the horizontal plane of Figure 2 shows the containers or storage bins having four corners and the arrangement of the four vertical upright members 16 at the corners of the containers or storage bins within the vertical storage column 44. Each corner section of the four vertical upright members, i.e., one from each of the four vertical upright members, ensures that the containers or storage bins stored within the storage column are guided to the correct position relative to any containers or storage bins stored within the storage column, or to stacks of containers or storage bins in the surrounding storage columns. A robotic loading handling device (not shown) that can operate on the grid structure 50 can lift the containers or storage bins as they are guided along the vertical upright members 16 through the grid cells 42. Therefore, the vertical upright member 16 has a dual purpose: (a) to structurally support the grid structure 50, and (b) to guide the containers or storage bins 10 to the correct position through their respective grid cells 42.

[0039] The upper plan view of a section of the grid structure 50 shown in Figure 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 extending in a first direction X, a second set of grid members 20 extending in a second direction Y, and the second set of grid members 20 passing transversely to the first set of grid members 18 in a substantially horizontal plane, i.e., the grid structure is represented by Cartesian coordinates in the X and Y directions. The terms “vertical upright,” “upright member,” and “upright column” are used interchangeably in this description to mean the same thing or feature. For the purposes of describing the present invention, points or joints where grid members intersect or cross, indicated by the squares in Figure 6, may be defined as nodes or intersections 52. It is clear from the layout of at least a portion or section of the known grid structure 50 that each intersection or node 52 of the grid structure 50 is supported by vertical uprights 16, i.e., both are in the same location. From the section or at least a portion of the grid structure 50 shown in Figure 6, the four adjacent grid cells are supported by nine vertical uprights 16, i.e., three sets of vertical uprights 16 support a three-column grid structure, in which case each column comprises three nodes 52.

[0040] Each of the grid members of the present invention may comprise track supports 18, 20 and / or tracks or rails 22a, 22b (see Figure 9), thereby mounting the tracks or rails 22a, 22b to the track supports 18, 20. A cargo handling device is operable to move along the tracks or rails 22a, 22b of the present invention. Alternatively, the tracks 22a, 22b may be integrated into the track supports 18, 20 as a single body, for example by extrusion molding. In certain embodiments of the present invention, the grid member comprises track supports 18, 20, and the tracks or rails 22a, 22b are mounted to the track supports 18, 20. At least one grid member in a set, for example a single grid member, may be subdivided or sectioned into separate grid elements that can be joined or linked together to form grid members 18, 20 extending in a first or second direction (see Figures 9 and 14). If the grid members include track supports, the track supports may also be subdivided into separate track support elements that are linked together to form the track supports (see Figures 10 and 13). Separate track support elements constituting track supports extending in the first and second axial directions are shown in Figure 9. Individual track support elements 56 used to constitute track supports 18, 20 are shown in Figure 10. In transverse sections, track supports 18, 20 may be solid supports with C-shaped, U-shaped, or I-shaped sections, or further with double C-shaped or double U-shaped supports. In certain embodiments of the present invention, the track support element 56 comprises double back-to-back C sections that are bolted together.

[0041] A connecting plate or cap plate 58, as shown in Figures 9 and 11, can be used to link or join individual track support elements 56 in both a first and second direction at a joint where multiple track support elements intersect at a node 52 in the grid structure 50; that is, the cap plate 58 is used to connect the track support elements 56 together to a vertical upright 16. As a result, the vertical upright 16 is interconnected at its upper end by the cap plate 58 at the joint where multiple track support elements intersect in the grid structure 50; that is, the cap plate is positioned at the node 52 of the grid structure 50. As shown in Figure 11, the cap plate 58 is cruciform with four connecting portions 60 for connecting to the ends of the track support elements 56 or at any point along their length at the intersection 52 of the track support elements. The interconnection of the track support elements to the vertical upright 16 at the node by the cap plate 58 is demonstrated in the cross-sectional profile of the node 52 shown in Figure 13. The cap plate 58, as shown in Figures 11 and 12, includes a plug or projection 62 sized to seat snugly within the hollow central section 46 of the vertical upright members 16 in order to interconnect the vertical upright members 16 to the track support. The plug 62 is received in a snap-fit ​​configuration within an opening of a corresponding shape in the vertical upright member or upright member 16 to prevent the cap plate from rotating relative to the vertical upright member 16 about a vertical axis along the longitudinal axis of the vertical upright member. The plug 62 includes a downward-extending elastic member that cooperates to snap into the opening defined by the hollow central opening section 46 of the vertical upright member. Also shown in Figure 13 are track support elements 56a, 56b extending in both vertical directions, corresponding to a first direction (X direction) and a second direction (Y direction). The connecting portion 60 is perpendicular to each other to connect to the track support elements 56a, 56b extending in the first and second directions. The cap plate 58 is configured to be bolted to the ends of the track support elements 56a and 56b, or along the length of the track support elements.Each of the orbital support elements 56a and 56b is arranged to interlock with each other at a node in order to form a grid structure 50 according to the present invention. To achieve this, the distal or opposing ends of each orbital of the orbital support elements 56a and 56b are provided with a locking feature 64 for interconnecting with the corresponding locking feature 64 of an adjacent orbital support element. In certain embodiments of the present invention, the opposing or distal ends of one or more orbital support elements are provided with at least one hook or tongue 64 that is receivable into an opening or slot 66 located midway through an adjacent orbital support element 56 at a joint where the orbital support elements intersect in the grid structure 50. Referring back to Figure 10 in combination with Figure 13, the hook 64 at the end of the orbital support element 56 is shown to be receivable into an opening 66 of an adjacent orbital support element that extends across a vertical upright 16 at a joint where the orbital support elements 56 intersect. Here, the hook 64 is provided on both sides of the orbital support element 56b up to the opening 66. In a particular embodiment of the present invention, the opening 66 is located halfway along the length of the track support element 56 such that, when assembled together, adjacent parallel track support elements 56 in the first and second directions are offset by at least one grid cell. This is demonstrated in Figure 9.

[0042] Tracks 22a, 22b are mounted on the track support elements 56 to complete the grid structure 50 after the track supports 56 are interlocked with each other to form a grid pattern comprising track supports 18 extending in a first direction and track supports 20 extending in a second direction. Tracks 22a, 22b are fitted onto the track supports 18, 20 in a snap-fit ​​and / or slide-fit arrangement (see Figure 9). As in the track support according to the present invention, the track comprises a first set of track 22a extending in a first direction and a second set of track 22b extending in a second direction, the first direction being perpendicular to the second direction. The first set of track 22a is subdivided into multiple track elements or elongated track elements 68 in the first direction such that when adjacent track elements parallel to the first direction are assembled together, they are offset by at least one grid cell. Similarly, a second set of track 22b is subdivided into multiple track elements 68 in a second direction such that when adjacent track elements in the second direction are assembled, they are offset by at least one grid cell. This is demonstrated in Figure 9. An example of a single track element or an elongated track element 68 is shown in Figure 14, which is contoured to guide a load handling device on a grid structure and typically comprises an elongated element contoured to provide a single track surface to allow a single load handling device to travel along the track, or a double track to allow two load handling devices to pass each other on the same track. The track surface is defined as the surface on which the wheels of the load handling device roll. When the elongated element is contoured to provide a single track, the track comprises opposing lips or ridges running along each longitudinal edge 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 restrict its lateral movement. For the purposes of the present invention, a lip or ridge running along each longitudinal edge of the track is defined as a guide surface for restraining the wheels of a load handling device onto the track.If the contour of the elongated element is a double track as shown in the track element shown in Figure 14, the track comprises two lips 69a, 69b that pass along the longitudinal edge of the track and a central lip or ridge 69c that passes parallel to the lips along the edge of the track, i.e., the track comprises three parallel ridges. When the two lips or ridges 69a, 69b extend longitudinally along the edge of the track element, the two lips 69a, 69b at the edge of the track element are defined as the first edge guide surface and the second edge guide surface, respectively. The central lip or ridge 69c is at the same distance from each of the lips or ridges at the edge of the track such that the area between the central lip and the lip at the edge of the track provides two track surfaces to allow the wheels of adjacent load handling devices to pass each other in both directions on the same track. In a particular embodiment shown in Figure 14, two lips or ridges 69c extending longitudinally along the central portion of the track are shown, cooperating with lips 69a, 69b at the edges of the track to provide track surfaces on both sides of the central ridge 69c. In all cases, when traversing the grid structure, the wheels of the load handling device are constrained on both sides or both surfaces of the wheels of the load handling device. Similar to the track support elements, multiple elongated track elements in the first and second directions are juxtaposed to form tracks in both directions. The mating portion of the track element 68 to the track supports 18, 20 has an inverted U-shaped cross-sectional contour molded to rest on or overlap the upper part of the track supports 18, 20. One or more lugs extending from each branch of the U-shaped contour engage with the ends of the track supports 18, 20 in a snap-fit ​​configuration. The track element 68 has notches or recesses 70 for accommodating the track support elements 56 in the upright columns discussed above. Since the orbital elements 68 are sized to extend or spread across a single vertical dimension within the grid structure, the notches 70 are formed either in the center or midway between each of the orbital elements 68. It also appears possible in the present invention that the orbitals 22a, 22b are not separate components but can be integrated with the orbital supports 18, 20.

[0043] The grid framework structure 14 can be conceived as a linear assembly of upright columns 16 supporting a grid structure 50 formed from intersecting horizontal grid members 18, 20, i.e., a four-walled framework. Upon receiving a customer order, a cargo handling device, operable to move along a track, is instructed to pick up a storage bin containing the ordered items from a stack within the grid framework structure and transport the storage bin to a pick station, where the items can then be removed from the storage bin and transported to one or more delivery containers. Typically, the pick station comprises 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 multiple adjacent conveyor units.

[0044] In a known fulfillment center, as shown in Figure 15, items and stock required to fulfill customer orders are located in containers or storage bins 10, which may be arranged along aisles. On the opposite side of the aisle from the containers or storage bins, a conveyor system is located, which carries customer delivery bins or containers. The conveyor system is arranged to pass through a certain percentage of delivery bins or containers moving on a backline conveyor via station containers and pick stations, and items ordered by customers are transferred by workers from storage bins or containers to customer delivery bins or containers. When a customer delivery container is located at a picking station 74 on the conveyor system, the customer delivery container is stopped, and workers select the required items from the storage bins or containers and place them into the customer delivery bins or containers. In a known robotic picking station, storage bins or containers are lifted by a loading handling device 30 from stacks containing stock items required to fulfill customer orders. Once lifted by the loading handling device 30, the storage bins or containers are delivered by the loading device to an output port 42b above or adjacent to the pick station 74. At the pick station 74, the required stock items or multiple stock items may be manually or robotically removed from the storage bins or containers and placed in a delivery container, which is filled to form part of a customer order and to be shipped in the appropriate time.

[0045] A known fillup center also includes, but is not limited to, a variety of other stations, including charging stations for charging rechargeable power supplies that power the load handling devices on the grid, and service stations for performing routine maintenance on the load handling devices. To accommodate one or a combination of these 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 level 76 supported by vertical beams 78 within the adjacent grid framework structure 14, and is an entirely independent structure. The mezzanine level 76 provides, for example, a tunnel for accommodating one or more pick stations and / or one of the stations described above. The area below the mezzanine level is typically worked in by people working at one or more service stations. Grid structures from the adjacent grid framework structure 14 extend across the top of the mezzanine level 76 to connect to the grids on both sides of the mezzanine level 76.

[0046] A grid structure extending across a mezzanine level for delivering storage containers to and / or picking them up from one or more pick stations below the mezzanine level comprises one or more ports 42b. As taught in the introduction of this specification, a port represents a location or grid cell from which a cargo handling device can drop off 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 transported in and out of the grid framework structure. The grid column in which a port is located may be referred to as a “delivery column”. The storage grid comprises two delivery columns. The first delivery column may comprise a dedicated drop-off port from which a container handling vehicle can drop off a storage container that is being transported further through the delivery column to an access station or transport station, for example, and the second delivery column may comprise a dedicated pickup port from which a container handling vehicle can pick up a storage container that has been transported through the delivery column from an access station or transport station. The storage container is sent to an access station and exits the pick station via the first and second delivery columns, respectively.

[0047] As is evident from Figure 15, the portion of the grid framework structure 14 above the mezzanine level 76 is shallower than the grid framework structures on either side of the mezzanine level 76, i.e., it can only accommodate one or two layers of containers in a stack. The grid structure 14b extending across the mezzanine level is supported by vertical upright members 16 mounted on the mezzanine level and is shorter in length than the vertical columns on either side of the mezzanine level. The shorter vertical upright members 16 are sized to accommodate only a few, for example, the depth of one or more containers in a stack, in order to ensure that the grid structure lies substantially in a horizontal plane when it extends across the mezzanine level, i.e., that 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 level 76 abuts against the grid framework structure 14 on either side of the mezzanine level 76. Multiple stacks of storage containers are stored in the vertical storage columns on either side of the mezzanine level. A robotic loading and unloading device capable of operating on a grid structure can retrieve a storage container from one or more vertical storage columns and transport this storage container to the upper mezzanine level, where the loading and unloading device can deliver the storage container to a pick station below the mezzanine level. As a result, the grid structure can be divided into different regions. To differentiate between a grid structure extending above the mezzanine level and a grid structure extending over multiple storage columns, the grid structure extending above the mezzanine level may be referred to as the first region of the grid structure, and the grid structure extending over multiple vertical storage columns on both sides of the mezzanine level may be referred to as the second region of the grid structure. Similarly, to differentiate between multiple upright members supporting the first region of the grid structure above the mezzanine level and multiple upright members supporting the second region of the grid structure, the multiple upright members supporting the first region of the grid structure may be referred to as the first set of upright members, and the multiple upright members supporting the second region of the grid structure may be referred to as the second set of upright members.Since the storage containers are stored in multiple stacks below the grid structure in the second area, the second set of upright members constituting the vertical storage columns is longer than the first set of upright members supporting the first area of ​​the grid structure at the mezzanine level.

[0048] Figure 16 shows an exploded view of a section of the grid framework structure within the junction area 84 between the mezzanine level and the vertical storage columns, and Figure 17 shows a top plan view of the grid structure highlighting the first and second regions of the grid structure. The junction area 84 shows the difference in length of the upright members 16, 16b that support the first region 80 and the second region 82 of the grid structure 14. The shorter of the upright members 16b, called the first set of upright members, is positioned to extend over the mezzanine level (not shown), and the second set of upright members is positioned to form multiple vertical storage columns 44 for storing storage containers in a stack. Due to the length of the upright members 16 that make up the vertical storage columns 44 compared to the length of the upright members 16b extending over the mezzanine level, the longer second set of upright members 16 is more mobile than the shorter first set of upright members. During ground movement, particularly during seismic events, the longer second set of upright members 16b vibrates with a greater amplitude than the shorter first set of upright members 16a. The vibration of the grid framework structure with vertical storage columns 44 is intensified by the stacking of storage containers stored within the vertical storage columns. The bending moment generated within the second region 82 of the grid structure as a result of the vibration of the longer second set of upright members 16b is transferred to the first region 80 of the grid structure extending over the mezzanine area. The larger the amplitude of the vibration of the second set of upright members, the greater the risk of damage to the interconnections of grid members where the grid members intersect at nodes within the first region 80 of the grid structure 14b. As discussed above, the upright members are interconnected to the grid members at the nodes of the grid structure by one or more fasteners via connecting plates or cap plates. Therefore, if the connections between the grid members at the nodes loosen and, in the worst-case scenario, are lost, components of the grid structure, particularly within the first area 80 above the mezzanine area, may detach and fall into the service area. Since people work in the service area, the loss of connections interconnecting the grid members to the upright members (the first set of upright members) within the first area poses a risk of injury to people working in the service area below.

[0049] Mechanical fuse The present invention mitigates the above problem by creating a weak point within the grid structure that preferentially breaks in order to separate different regions of the grid structure, thereby preventing the transfer of bending moments from one region of the grid structure to another region of the grid structure. In the particular embodiment shown in the upper plan view of Figures 16 and 17, the weak point 86 is preferentially located within a joining area 84 where different regions of the grid structure meet, i.e., within the grid structure between a first region 80 and a second region 82. The weak point 86 is configured to preferentially break when a tensile force acting on the weak point in a given direction exceeds or equals a given load, but does not necessarily break other connections of the grid members within the grid structure, i.e., the interconnection 52 between the upright members and the grid members via, for example, the cap plate 158. In other words, the weak point is configured to break under the applied load, but does not necessarily break the interconnection between the upright members and the grid members. The predetermined direction is parallel to the longitudinal direction of the grid members 18, 20 within the joining area 84 between the first region 80 and the second region 82 of the grid structure 14b, as indicated by the arrow in Figure 17. This may be along the X direction or the Y direction, depending on the orientation of the grid members within the grid structure. In order to preferentially create weak points within the grid structure, the predetermined load required to break the weak points must be smaller than that required for other connections of the grid members within the grid structure. More specifically, these other connections are those discussed above, namely the interconnections 52 between the upright members and the grid members via the cap plate 158.

[0050] In a particular embodiment of the present invention shown in Figure 18, a weak point in 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 region of the grid structure and a second region of the grid structure (see Figure 19). Since the wheel assembly of a robotic load handling device comprises a pair of wheels at the front and rear of the vehicle body and a pair of wheels on both sides of the wheel body (see Figure 4), the bridging joint assembly 88 is positioned as one or more pairs of connections between the first region and the second region of the grid structure, i.e., 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 present invention is shown in Figure 18. The bridging joint assembly 88 in the example shown in Figure 18 comprises 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 the respective cap plate 158 by one or more bolts, as shown in Figure 18, to interconnect with the adjacent upright member in the grid structure. The adjacent grid members connected together by the bridging joint assembly 88 function as a single elongated grid element extending between the adjacent upright members in the grid structure.

[0051] When the ends of adjacent grid members are joined together by the bridging joint assembly of the present invention, the tracks 22a and 22b are positioned on each of the adjacent grid members such that a continuous track surface extends across the ends of the adjacent grid members (see Figure 19). This is to allow the wheel assembly of a robotic cargo handling device to move across the bridging joint assembly of the present invention. In a particular embodiment of the present invention shown in Figure 18, the grid members function as track supports, and separate track elements are mounted on the track supports, for example, in a snap-fit ​​arrangement.

[0052] Brackets 92 that join the ends of adjacent grid members are in the form of plates that overlap the ends of the adjacent grid members. In a particular example shown in the cross-sectional view of the bridging joint assembly shown in Figure 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 opposing or free ends of the brackets are connected to the ends of the adjacent grid members by one or more fasteners, such as bolts, screws, or pins, which are received in openings within the ends of the grid members, within the joining area where they overlap the ends of the adjacent grid members. One or more fasteners are arranged to break when the applied load exceeds or equals a predetermined load, separating the ends of the adjacent grid members and thereby preferentially separating different areas of the grid structure (see Figure 21). In a particular example shown in Figure 20, the mechanical fuse 90 comprises a shear pin 94 having a break zone 96, the break zone comprising a reduced cross-sectional area or neck portion of the pin, which is arranged to shear when the applied load on the break zone exceeds or equals a predetermined load. In the specific example shown in Figure 20, the mechanical fuse comprises two shear pins 94 linked together by a linkage 98, so that when one pin breaks, the linkage keeps the shear pins together.

[0053] To prevent other connections in the grid structure, such as the interconnections between upright members and grid members, from breaking and loosening under a predetermined load, the predetermined load for breaking the mechanical fuse is set to be less than the load at the interconnections between multiple upright members and grid members in the grid framework structure. Vibrations of the grid frame structure as a result of ground movement generate tensile forces on the bridging joint assemblies that link different regions of the grid structure together. When the tensile force exceeds or equals the predetermined load that breaks the shear pins, at least one end of the bracket 92 separates from its connecting end of the grid member, i.e., this tensile force is less than the load that holds the grid members in the grid structure together at the interconnections with the upright members. This is demonstrated in the schematic diagram shown in Figure 21, which shows the separation of the ends of 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 the particular embodiment shown in Figure 18, at least two fasteners at each end of the bracket are used to connect the bracket to the end of the grid member. Therefore, in order to separate the ends of the grid members, 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.

[0054] While a mechanical fuse 90 comprising one or more shear pins is arranged to connect a bracket to the end of an adjacent grid member, other means for providing a preferred weak point with a mechanical fuse within the grid structure are equally applicable in the present invention. For example, one or more fasteners used to interconnect upright members to grid members via a connecting plate or cap plate can function as a mechanical fuse. For example, one or more bolts connecting a grid member to a connecting portion 60 of a cap plate 158 may be manufactured to have a failure zone arranged to shear under an applied load exceeding or equal to a predetermined load in order to detach the grid member from the connecting portion, and thus from the cap plate (see Figure 9). In a particular example of the present invention shown in Figure 18, at least two fasteners 100 are used to connect the ends of grid members to a cap plate. Such two fasteners may be manufactured as a mechanical fuse arranged to shear when the load exceeds or equals a predetermined load. Other means of incorporating weak points in a grid structure with mechanical fuses include fabricating a failure zone, such as a grid member having a reduced cross-sectional area, such that a portion of the grid member breaks when a tensile force exceeds or equals a predetermined load. Similarly, a bracket that connects the ends of adjacent grid members may have a failure zone configured to break under an applied load that exceeds or equals a predetermined load. In all of these different examples, the weak points with mechanical fuses are configured to preferentially isolate different regions of the grid structure during ground movement, such as during an earthquake event.

[0055] While mechanical fuses are configured to preferentially isolate different areas of the grid structure, movement of the grid structure is unavoidable during a series of operations of the grid frame structure in a fulfillment center. For example, temperature changes in the environment in which the grid frame structure is located can cause different parts of the grid frame structure to expand and contract as a result of thermal expansion and contraction. Without measures to account for thermal expansion and contraction, there is a risk that when the length of one or more grid members expands or contracts, areas of the grid structure may deform or buckle, increasing the likelihood that one or more robotic load handling devices operating on the grid structure may derail.

[0056] In the specific example shown in Figure 22(a to c), opposing ends of bracket 92 of bridging joint assembly 88 are connected to the ends of adjacent grid members 18, 20 by sliding connections. The sliding connection between bracket 92 and the ends of the grid members comprises one or more sliding members, each having a bolt or pin positioned to slide along a slot 102 formed in the end of the adjacent grid member, allowing the separation between the ends of the grid members to change longitudinally, i.e., in the X or Y direction. The cooperation of the sliding bolt and the slot 102 is clearly shown in Figure 21. The length of the advance of the end of the grid member is determined by the length of the slot 102, and each opposing end of the slot 102 acts as a stop to prevent further separation of the end of the grid member. When one or more bolts extending through the slot reach their ends of advance determined by the length of the slot, the end of the grid member is prevented from moving further. One or more bolts extending through the slots may each be provided with a sliding bearing 104 (see Figure 21), or alternatively, a roller bearing, to assist the sliding of the bolts along the slots. The sliding connection in the particular embodiment shown in Figure 22(a to c) shows a slot formed within the end of a grid member, but the reverse is also true: a slot is formed within a bracket that joins the ends of the grid members together, and bolts that fasten the bracket to the end of the grid member are arranged to slide along the slots within the bracket.

[0057] Different stages of separation of the ends of grid members 18 and 20 are shown in Figures 22(a to c). Figure 22a shows the ends of grid members in a closed configuration, and Figures 22b to 22c show different stages of separation of the ends of grid members as adjacent grid members move longitudinally to a maximum extent 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 bridging joint assembly exceeds or equals a predetermined load in order to separate different regions of the grid structure. The length of the slot, and therefore the separation of the ends of adjacent grid members, is calculated based on the level of movement of the grid members as a result of the stretching and contracting of the grid members. Typically, in normal operation, the length of the slot allows for movement of grid members in either the X or Y direction ranging from about 10 mm to about 180 mm as a result of thermal expansion and contraction. If the movement of the grid structure generates tensile forces that cause the grid members to move beyond a predetermined length, the ends of the slots prevent such further movement of the grid members. However, when the tensile force on the bridging joint assembly exceeds or equals a predetermined load, the bolts are configured to break when they reach the end of their respective slots 102, thereby separating the ends of the grid members and isolating different regions of the grid structure. In a particular embodiment of the invention shown in Figures 21 and 22, the grid members connected by the brackets 92 are I-beams. The slots 102 are formed at the ends of the I-beams, cooperating with mechanical fuses 94 that fasten the brackets 92 to the ends of the grid members.

[0058] To provide a continuous track surface on grid members 18, 20 when the ends of the grid members separate, the bridging joint assembly 88 further comprises an extension joint having a first track element 106 and a second track element 108, and a bridging 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 adjacent grid members, and the second track element 108 is positioned overlapping at the other end of adjacent grid members. The bridging member 110 extends across the ends of the first and second track elements 106, 108. Each of the first and second track elements, as well as the bridging member 110, represents at least a portion of a single elongated track element. Thus, the first and second track elements, as well as the bridging member, have respective interface portions that are contoured to interpose to form a single elongated track element that provides a continuous track surface.

[0059] The upper surface of the bridging member 110 is contoured such that there is a transition along the expansion joint from the first track element to the second track element. In the specific example shown in Figure 23(a and b), the contours of the first and second track elements provide a double track comprising a central ridge and tracks on both sides of the central ridge. The upper contour of the bridging member 110 is shown as two track or rolling surfaces 110a, 110b that extend longitudinally across the distal end of the grid member. The track surfaces of the bridging member 110 are arranged to provide rolling surfaces for the wheels of the robotic cargo handling device. The rolling surfaces of the track surfaces extend across the width of the wheels of the robotic cargo handling device. The bridging member 110 has a first end 112 fixed to the first track element 106 and a second end 114 that can ride along a groove 116 formed in the second track element 108. For example, the second end 114 of the bridging member 110 is equipped with a sliding anchor 118 that is restricted to moving along a guide 116 having a groove formed in the second raceway element, as shown in Figure 24. Also shown in Figure 24 are sliding anchors 118 extending through grooves in the end grid members 18, 20 that support the second raceway element. When the ends of adjacent grid members separate, the bridging member 110 bridges the gap created between the ends of adjacent grid members. In a particular example shown in Figure 23b, the second end 114 of the bridging member 110 is positioned to overlap the second raceway element 108.

[0060] However, in order to provide a continuous track surface, other means for bridging the gap across the first and second track elements when the ends of adjacent grid members separate are applicable in the present invention. In an example shown in Figure 25 and incorporated into a grid structure in Figure 26, the bridging member 110 may be formed as a projection male portion 110c of a first track element that is received in a correspondingly shaped recess 108b within a second track element 108. The bridging member 110 is shown in Figure 25 formed integrally with the first track element 106 as a projection male portion, and the second track element comprises a receiving female portion 108b. Compared to the bridging member 110 shown in Figures 23(a and b), where the track surfaces 110a,b of the bridging member 110 extend across the width of the wheel, in the example shown in Figure 25, the track surface of the bridging member formed as a projection male portion 110c contacts only at least half the width of the wheel when the wheel traverses across the bridging member 110. The other half of the width of the wheel does not contact the track surface of the projection male portion 110c. The robotic cargo handling device is prevented from derailing by the restraint of the pair of wheels on either side of the vehicle body. This can be demonstrated by the schematic diagram shown in Figure 27, which shows two robotic cargo handling devices 30a, 30b lying side by side on a track provided by a set of parallel bridging members 110 of the present invention, with each bridging member 110 having a central lip or ridge 110d for restraining only one side of each wheel 34. Since each robotic cargo handling device has a pair of wheels 34 at the front and rear of the vehicle body, restraint on only one side of the wheels prevents lateral movement of the robotic cargo handling device on the track, thereby preventing the robotic cargo handling device from derailing. In the particular example shown in Figure 27, the outer edges of the wheels of the cargo handling device are restrained by contacting the central ridge 110d of the bridging member 110 when the ends of adjacent grid members separate.

[0061] Typically, the bridging member 110 is a relatively thin strip of metal configured to span the ends of the first and second track elements 106, 108 when the ends of adjacent grid members separate, in order to provide a continuous track surface across the ends of the first and second track elements. Given that the weight of a robotic cargo handling device that can operate on the track can exceed 100 kg, there is a risk that the bridging member 110 will bend under the weight of the robotic cargo handling device moving across it. To prevent the bridging member from bending under the weight of a robotic cargo handling device that can operate on the track, the bridging joint assembly further includes a support 120 midway between the ends of the first and second track elements 106, 108 (see Figures 25 and 26). The upper end of the support 120 is contoured to support the bridging member 110 when the ends of adjacent grid members separate (see Figures 25 and 26). In a particular embodiment shown in Figure 25, the support 120 is fixed to the bracket 92 by one or more bolts that join the ends of adjacent grid members together. The support 120 is shown fixed to the bracket 92 midway between the ends of the first and second track elements 106, 108, so that when the ends of the grid members are joined together as shown in Figure 22a, the ends of adjacent grid members abut against the support 120 so that the support acts as a spacer between the ends of adjacent grid members.

[0062] In the specific examples shown in Figures 16 and 17, the same type of grid members constitute the grid structure, and consequently, the interconnections between the upright members and the grid members are primarily provided by the same type of cap plates. In other words, the bridging joint assemblies of the present invention used to connect different regions of the grid structure comprise the same type of grid members. In this particular example shown in Figure 16, the grid members comprise back-to-back C sections having substantially I-shaped cross-sectional contours. By interconnecting the upright members constituting the vertical storage columns using such a 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 B seismic events, but the same cannot be said for large changes in ground movement characteristic of type D seismic events. To cope with the large deflections in the grid framework structure characteristic of type D seismic events, the grid members constituting the grid structure need to be more robust with respect to bending stiffness.

[0063] In a particular example of the present invention shown in Figure 28, the grid members 18, 20 constituting the region of the grid structure comprise tubular beams 122 having a cross-section that largely comprises a hollow central section. The use of tubular beams 122 for constructing grid members compared to beams of other shapes provides greater resistance to bending because the walls of the tubular beams 122 can resist bending in all directions. The tubular cross-sectional contour 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 grid members constructed as tubular beams is much greater than that of grid members in type A or B grid structures discussed above. Furthermore, rather than bolting grid members at intersections where grid members meet, which is prone to loosening in strong seismic events, grid members are preferably welded at intersections 52. Welded joints at intersections 52 provide a more robust and rigid joint at the intersection where grid members meet. When bending moments are transferred to the intersection, welding of grid members at intersections 52 means that the joint can withstand the load at that intersection.

[0064] The grid structure is subdivided into multiple subframes as shown in Figures 29 and 30, so that one or more of the subframes 124 have at least one grid cell 42. The multiple subframes 124 are assembled together when the grid structure is built in site. To comply with building regulations, ideally the individual subframes are bolted together when they are assembled in site. The ends of the grid elements constituting the subframes have connecting portions 125 positioned to face the corresponding connecting portions of adjacent subframes. The connecting portions 125 have one or more holes for receiving bolts.

[0065] Separate track support elements 126a, 126b are directly mounted to the grid element 122 to provide a track or rail for the cargo handling device to move along the grid (see Figure 31). The track support elements 126a, b allow the track or rail 128a, b to be fitted into the grid element 122. Multiple track support elements 126a, b are distributed on the grid element 122 of a subframe 124 having a contour molded to receive the track. Thus, compared to the grid elements of the grid framework structure discussed above (back-to-back C-shaped sections with contours for receiving the track by snap-fit ​​arrangement) in which the track support elements are incorporated into the grid elements of the grid, the track support elements 126a, b of the seismic grid framework structure are separate from the grid element 122. Figure 29 shows a top view of a subframe 124 according to an embodiment of the present invention, showing track support elements 126a, b extending in the X and Y directions and directly mounted on a tubular grid element 122, and Figure 31 shows a cross-sectional view of the subframe showing the engagement of tracks 128a, b with grid members 18, 20 by track support elements 126a, b according to an embodiment of the present invention. Similar to the tracks mounted on grid elements in the grid framework structure discussed above, tracks 128a, b are fitted to grid elements 122 in the seismic grid framework structure via track support elements 126a, b by snap-fit ​​and / or sliding-fit arrangements.

[0066] When the seismic grid framework structure of the present invention does not have cap plates for joining grid elements together, so that the grid elements are welded together at intersections, plugs 162 for connecting upright columns 16 are directly attached to the underside of the subframe 124 at the intersections where the grid members intersect, in order to interconnect the vertical upright members to the grid of the seismic grid framework structure of the present invention (see Figure 30). In a particular embodiment of the present invention, the plugs 162 are welded to the underside of the subframe at the intersections where the grid members 18, 20 intersect, i.e., at the nodes of the grid structure. As shown in Figure 30, four plugs 162 can be seen directly attached to the underside of the subframe 124 at the intersections where the grid members 18, 20 intersect. However, other beams of structural bending resistance may be used to increase the structural rigidity of the grid structure. These include, but are not limited to, I-beams.

[0067] Type D grid structures are more suitable when the grid members of the grid structure are subjected to increased bending moments and stresses due to ground movement. The grid members above the vertical storage columns are susceptible to increased bending moments due to the height or length of the vertical upright members for storing multiple storage containers within the vertical stack; therefore, the grid members constituting the grid structure above the vertical storage columns tend to be constructed from beams with greater bending resistance, such as the tubular beams discussed above. However, other areas of the grid structure, namely the areas above the mezzanine level, do not necessarily need to have the same level of structural rigidity as the grid structure above the vertical storage columns and can be based on beams with less bending resistance, such as the back-to-back C sections discussed above. This is illustrated in the section of the grid framework structure shown in Figure 32, where different areas 80, 82 of the grid structure are composed of different types of grid members 18, 20. However, the problem with having different regions 80 and 82 of the grid structure having grid structures with different levels of structural rigidity is that a structurally rigid grid structure may topple a more vulnerable grid, or at least cause significant damage to that more vulnerable grid structure, during a strong seismic event characteristic of a Type D seismic event. The bridging joint assembly of the present invention can link different regions of a grid structure even when each region of the grid structure comprises different types of grid members. In the particular example shown in Figure 32, the bridging joint assembly of the present invention is used to link region 82 of the grid structure comprising tubular beams 122 with region 80 of the grid structure comprising back-to-back C sections. However, the bridging joint assembly 88 of the present invention is not limited to the grid member types shown in Figure 32 and can be used to link together any type of grid member from different regions of the grid structure.

[0068] For ease of explanation, a grid structure with more fragile grid members can be referred to as the first region 80 of the grid structure 14b, and a grid structure with more structurally robust grid members can be referred to as the second region 82 of the grid structure 14b. The grid members constituting the first region 80 of the grid structure can be referred to as the first type of grid members and can correspond to the grid members shown in Figure 10. Similarly, the grid members constituting the second region 82 of the grid structure can be referred to as the second type of grid members and can correspond to the grid members shown in Figure 28. Because the grid members constituting the first and second regions 80 and 82 of the grid structure 14b differ in shape and dimensions, different brackets 158 and 130 are required to connect the first and second regions 80 and 82 of the grid structure 14b together by incorporating the bridging joint assembly 88 of the present invention. The different brackets 158 and 130 that connect the different regions 80 and 82 of the grid structure 14b together are necessary to ensure that the grid level remains horizontal across the different regions of the grid structure. The bridging 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 Figure 33. The other end of each adjacent grid member is connected to its upright member by a first type bracket 158 ​​and a second type bracket 130 to compensate for the height difference of the grid members constituting the first and second regions 80, 82 of the grid structure. For ease of explanation, adjacent grid members connected together by the bridging 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 member linking the first and second regions of the grid structure. Thus, the first region of the grid member is connected to the upright member by the first type bracket 158, and the second part of the grid member is connected to the adjacent upright member by the second type bracket 130.In the specific example shown in Figure 33, the first type of bracket is a cap plate 158, since the grid members in the first region of the grid structure are generally back-to-back C sections, i.e., first type grid members. However, the grid members in the second region of the grid structure are different because they need to be structurally more elastic to ground movement, so the second type of bracket 130 includes a column or spacer 132 having an upper end 134 connected to the end of the second portion of the grid member and a lower end 136 connected to an upright member, in order to accommodate the height difference of the grid members in the first region of the grid structure and to ensure that the track remains horizontal within the grid structure. The column or spacer 132 compensates for the height difference between the grid structure in the first region and the grid structure in the second region. The grid members in the second region of the grid structure are generally tubular with a hollow cross-sectional contour, i.e., second type grid members, as shown in Figure 28. In all cases, the bridging joint assembly 88 behaves as discussed above, in which case the mechanical fuse 90 is configured to preferentially break when the tensile force acting on the mechanical fuse exceeds or equals a predetermined load necessary to separate the first region of the grid structure from the second region of the grid structure.

[0069] Two-way expandable joint A telescopic joint comprising a first orbital element 106 and a second orbital element 108, and a bridging member 110 extending across the ends of the first and second orbital elements, can compensate only for longitudinal movement of the grid members (indicated by the arrows in Figure 34), and thus can cover movement in either the X or Y direction only. To compensate for movement of grid members in both the X and Y directions, a separate telescopic joint is required to link the ends of adjacent grid members extending in the X and Y directions to cover movement in both longitudinal directions. To compensate for movement of grid members in both the X and Y directions in the present invention, at least one of the upright members is interconnected to a grid member by a connection with a pivotable joint, thereby allowing the grid member to rotate in a horizontal plane about a vertical axis extending through the pivotable joint. When the grid member is connected to the upright member by a bracket, in this case a cap plate 158, a pivotable connection exists between the cap plate and the end of the grid member, as demonstrated in Figure 34. As discussed above, the cap plate 158 is restricted from rotational movement by a plug 62 received in a corresponding hollow central section 46 of a vertical or upright member 16, which extends downward from the cap plate. The pivotable connection is provided by a bolt or bearing member extending through an opening 238 in the connecting portion of the cap plate 158, as shown in Figure 38.

[0070] As grid members move as a result of extension and / or contraction, pivotable connections can absorb the movement of grid members in either the X or Y direction. Longitudinal movement is absorbed by the sliding relationship of the track elements 106, 108 discussed above. To incorporate movement in both the X and Y directions, at least one end of grid members in a grid structure connected or joined together by the bridging joint assembly of the present invention is pivotably connected to its respective upright member.

[0071] To better illustrate the concept of a pivotable joint in conjunction with the sliding relationship of the orbital elements to cover movement in both the X and Y directions, the relationship between the pivotable connection of the grid member and the sliding connection of the orbital elements positioned on the grid member is best illustrated with reference to a first upright member 16a and a second upright member 16b (see Figure 32) interconnected by a grid member extending between both upright members, as shown in Figures 34 and 35. In the particular example shown in Figure 34, the ends of adjacent grid members extending between the first upright member and the second upright member are connected together by a bridging joint assembly 88 of the present invention to allow longitudinal movement of the grid member. The first upright member is interconnected to the grid member at its upper end by a connection with a pivotable joint, thereby allowing the grid member to rotate in a horizontal plane about a vertical axis extending through the pivotable joint when one of the first or second upright members moves relative to the other of the first or second upright member. In a particular example shown in Figure 34, the ends of adjacent grid members 18, 20 extending between a first upright member and a second upright member are pivotally connected to their respective upright members to allow movement of one of the first or second upright members relative to the other. The rotation of the grid members causes corresponding rotational motion of the orbital elements 106, 108 positioned on the grid members, as demonstrated in schematic diagrams of parts of the grid structure shown in Figures 36 and 37. This allows the orbitals 22a, b to move laterally when subjected to forces in the X or Y direction. In a particular example shown in Figure 36, the orbital is made capable of moving laterally in a horizontal plane in the X direction.

[0072] To accommodate longitudinal movement, a joint between the ends of adjacent grid members, each having first and second orbital elements 106, 108, and a bridging member 110 extending across the first and second orbital elements, allows one end of the bridging member to slide longitudinally (see Figure 36), in this case in the Y direction. Thus, rotational movement of the connected grid members by the pivotable joint allows for movement of a portion of the grid structure in the X direction, and the bridging joint assembly connecting the ends of the grid members together allows for longitudinal movement in the Y direction; that is, both the X and Y directions may be covered by a single thermal expansion section extending between adjacent vertical or upright members.

[0073] The movement of one of the first or second upright members relative to the other, resulting from the pivotable joint connecting the grid members to the upright members, displaces the track elements relative to adjacent track elements in the region where the track elements intersect at node 52 of the grid structure. This displacement causes misalignment of the upper track contour, particularly at the node, as demonstrated in Figure 37. If the rotation of the grid members, and therefore the corresponding rotation of the track, becomes excessive enough to interrupt the continuous track surface in the joining area where the track elements converge at the node in the grid structure, the wheels of the robotic load handling device risk derailing when they intersect the track elements. To prevent excessive misalignment of track elements as a result of the grid members rotating around their pivotal connection to the upright members, the pivotal joint is limited to rotating by a predetermined angle from its center or nominal position, in which case the predetermined angle is small enough to allow the wheels of the robotic load handling device to traverse across the misaligned track elements. The pivotable joint is limited to rotating by a predetermined angle by providing a stop member positioned to rotate within an arc-shaped slot having a radius of curvature centered on the pivotable joint. As shown in Figure 38, in addition to the opening 238 in the connection portion of the cap plate 158 for housing the pivotable joint between the end of the grid member and the cap plate, the connection portion of the cap plate 158 further comprises at least one arc-shaped slot 140 through which a stop member 142 (see Figure 35) extends, thereby allowing the grid member connected to the cap plate 158 by the pivotable joint to rotate by a predetermined angle defined by the arc of the arc-shaped slot 140. In the particular embodiment shown in Figures 42(a and b), the stop member 142 comprises a shear pin 146 having a breaking zone 96. The predetermined angle can be in the range of 1° to 20°, preferably in the range of 5° to 20°. During operation, the stop member 142, which is received within the arched slot 140, is positioned so as to be guided by the arched slot 140 to a limit determined by the end of the arched slot 140.The grid member is prevented from rotating further when the stop member 142 contacts the opposing ends of the arched slot 140. In a particular embodiment shown in Figure 38, the two arched slots 140 are shown as being located within the connection portion of a cap plate / bracket laterally positioned on either side of a pivotable joint, i.e., as opposing arched slots 140. Each of the arched slots 140 defines an arc in which the stop member 142 is received, having a radius of curvature centered on the pivotable joint.

[0074] The pivotable connection between the grid member and the upright member is not limited to the first type of bracket having a cap plate 158 as shown in Figure 38, but can also be provided between the connection between the second type of bracket 130 and the type D grid member discussed above, i.e., the second type of grid member (Figures 33 and 39). Here, the uppermost connection portion 134 of the second type of bracket 130 comprises an opening 338 for accommodating a pivotable joint and an arched slot 240 having a radius of curvature centered on the pivotable joint. The lowermost connection portion 136 of the second type of bracket 130 is fixed to the upright member. Using the terminology discussed with reference to Figures 34 and 35, the lowermost connection portion 136 of the second type of bracket 130 is fixed to the second upright member 16b. In a particular example of the invention shown in Figure 32, the first upright member 16a is shorter than the second upright member 16b. As a result, for example, ground movement 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 discussed above, in order to compensate for the difference in vibration amplitude between the first upright member 16a and the second upright member 16b, the type D grid member or second type grid member interconnecting the second upright member 16b within the second region of the grid structure is configured to provide better structural integrity or rigidity during ground movement than the first type grid member. As a result, the cross-sectional profile of the second type grid member is sized differently from, for example, the cross-sectional profile of the first type grid member, for example, 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 the grid structure remains substantially horizontal when a first region of the grid structure having the first type grid member is linked or connected to a second region of the grid structure having the second type grid member.

[0075] By adjusting the type of brackets used to interconnect the upright members to the grid members within the grid frame structure, the first upright members can be displaced laterally relative to the second upright members by the pivotable connection between the grid members and their respective upright members, regardless of the type of brackets used to connect the grid members to the upright members (see Figures 40 and 41). Thus, longitudinal extension and contraction of the grid members are brought about by the movement of the first orbital element 106 relative to the second orbital element 108. Bracket 92 maintains the connection between the ends of the grid members supporting the first and second orbital elements 106, 108. Vertical movement in the longitudinal direction is brought about by the rotation of the grid members 18, 20 relative to the upright members to which they are connected, via a second type of bracket 130.

[0076] In the event that the force required to rotate the grid member exceeds a predetermined load characteristic of an earthquake event, the stop member 142 can function as a mechanical fuse positioned to break when the applied load in the first or second direction generates a rotational force exceeding the failure point of the mechanical fuse. An example of a stop member 142 with a failure zone 96 is shown in Figures 42(a and b), where Figure 42a shows the stop member 142 in an intact state, and Figure 42b shows the stop member 142 in a broken state, allowing the grid member to rotate beyond the arc defined by the arched slots. Also shown in Figures 42(a and b) are optional linkages 144 of stop members on both sides of a pivot joint to allow a shear pin 146 to move together within its respective arched slots 240 (see Figure 39). A cross-section along line XX in Figure 40 of a pivotable connection between an upright member and a grid member, incorporating stop members 142 received in their respective arched slots 240 on both sides of the pivot joint, is shown in Figures 43 and 44. When a force substantially perpendicular to the longitudinal direction of the grid member is applied, and the rotation angle of the grid member exceeds a predetermined angle determined by the arc of the arched slot 240, 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 grid members 18, 20 and the upright member shown in Figure 44. To compensate for the effects of external forces that distort the grid structure and cause damage to the grid members and tracks, the mechanical fuse 94 connecting the grid member to the upright member preferentially breaks, allowing the grid member to rotate. In other words, the mechanical fuse 94 provides a sacrificial element within the grid structure that preferentially breaks to prevent or mitigate large distortions of the grid structure. If one or more interconnections between a grid member and an upright member are provided with a pivotable joint, the mechanical fuse allows a first region of the grid structure to move relative to a second region of the grid structure around one or more pivotable connections.The effect of the mechanical fuse failure resulting in the rotation of adjacent grid members between the first and second regions of the grid structure is demonstrated in the schematic diagram shown in Figure 45. Here, the orbital elements 106 and 108 of the bridging joint assembly 88 are rotated beyond a predetermined angle, resulting in a large displacement of the upper contour of the orbital elements relative to adjacent orbits at the nodes of the grid structure. In the example shown in Figure 45, the rotational movement of the orbital elements by the pivotable joint results in a displacement of the orbital elements 106 and 108 relative to orbits 22a and 22b at the nodes of the grid structure. The failure of the mechanical fuse as a result of ground movement characteristic of seismic events protects different regions of the grid structure from further damage, and furthermore, prevents the region of the grid structure from causing injury from fragments of the grid structure falling below the grid structure, particularly to people below the mezzanine level.

[0077] Each of the orbital elements of a thermal expansion joint has an interface or pairing portion that allows the orbital elements to connect with each other to form a single elongated orbital element as discussed above, but the expansion joint relies on having components of different shapes to pair the first and second orbital elements together. In other words, the interface portion of each orbital element of the expansion joint has a pairing contour of a different shape, so that when the pairing contours of different shapes pair with each other at their respective interface portions, a single orbital element is formed. For example, in the embodiment of a thermal expansion joint shown in Figure 25, where the bridging member 110 is formed as a projection male portion 110b of the first orbital element that is received in a corresponding recess 108 within the second orbital element 108, the first and second orbital elements need to be molded differently to connect together to form a single elongated orbital element.

[0078] In another embodiment of the present invention shown in Figure 46, the interface portions 210a, b of the first and second orbital elements 206, 208 are formed such that the interface portion 210b of the second orbital element 208 is rotated 180° around the vertical axis of the interface portion 210a of the first orbital element 206. In other words, the interface portion 210a of the first orbital element 206 is a duplicate of the second orbital element 210, but rotated 180° around the vertical axis so that the interface portions 210a, b of the first and second orbital elements can interlock to complete the double orbital surfaces 110a, 110b shown in Figure 47(a to c), i.e., to complete a single elongated orbital element extending in a first or second direction. This has the advantage that only a single shape of orbital element is required for both the first and second orbital elements, which further has the advantage of reducing equipment costs in the manufacture of the thermal expansion joint. Since the first orbital element 206 and the second orbital element 208 correspond to at least a portion of a single elongated orbital element, the first orbital element can be defined as the first orbital element portion and the second orbital element can be defined as the second orbital element portion. Accordingly, Figure 46 shows the first orbital element portion 206 and the second orbital element portion 208 connected to each other at their respective interface portions to form a single elongated orbital element. In the particular embodiment of the invention shown in Figure 46, the first and second orbital element portions are substantially identical but rotated by exactly 180° around the vertical axis. Figures 47(a to c) show the first orbital element portion 206 and the second orbital element portion 208 being joined together to form a single elongated orbital element extending in either the first or second direction.

[0079] For the purposes of the present invention, a 180° rotation is interpreted to cover substantially 180° and relies entirely on the contours of the interface portions of the first and second track elements, having tolerances to allow the first and second track elements to connect to each other to form a single elongated track element extending in either the first or second direction. The track surface is defined as the surface on which the wheels of the cargo handling device roll. A dual track comprises guide surfaces 69a, 69b, 69c to restrain the wheels of the cargo handling device onto their respective track surfaces. In particular embodiments of the present invention, the guide surface of the dual track comprises opposing lips or ridges 69a, 69b (one lip on one side of the track and the other lip on the other side of the track) that run along each longitudinal edge of the track to guide each wheel on the track or to restrict its lateral movement, and a central lip or ridge 69c that runs parallel to the lips along the edge of the track. The central lip or ridge 69c is at the same distance from each of the lips or ridges 69a, 69b at the edge of the track, thereby providing two track surfaces 110a, 110b in the area between the central lip 69c and the lips 69a, 69b at the edge of the track, allowing the wheels of adjacent load handling devices to pass each other in both directions on the same track.

[0080] In certain embodiments of the present invention, the interface portions 210a, 210b of the first and second track elements 206, 208 each comprise three steps 212a, 212b, 212c, which connect together when the first and second track elements 206, 208 are joined together, thereby causing the guide surfaces 69a, 69b and the central guide surface 69c on the outer edges of each track element to contact each other so as to pass continuously along the first and second track elements 206, 208 as shown in Figure 47(a). The wheel assembly of the load handling device, comprising a pair of wheels at the front and rear of the load handling device, can roll on the track surface across the first and second track elements 206, 208. Movement of the track elements due to thermal expansion and contraction, resulting from the sliding connection between the first and second track elements, is shown in Figures 47(b and c). When the first and second orbital elements separate, gaps 214a, 214b, and 216 are generated within the orbital surface between the first orbital element 206 and the second orbital element 208. The shape of the interface portion of the first and second orbital elements is such that the two gaps 214a and 214b, namely the first gap 214a in the first orbital surface 110a and the second gap 214b in the second orbital surface 110b, are offset from each other in the longitudinal direction of at least a portion of the orbit, with the first gap 214a being offset from the second gap 214b in the longitudinal direction of the orbit. In addition to the first and second gaps 214a and 214b in the first and second orbital surfaces 110a and 110b, the central ridge 69c also separates to generate a central gap or a third gap 216. 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 separate, as demonstrated in Figures 47(b) and 47(c). The interface portions 210a, 210b of the first and second track elements 206, 208 are such that there is no continuous gap extending laterally across the track when the first and second track elements are separated. This is to prevent the wheels of the cargo handling device from descending or falling into the gap when the first and second track elements separate.

[0081] The offset arrangement of the first and second gaps 214a, 214b ensures that a continuous track surface remains for the wheels of the cargo handling device to travel across the telescopic joint when the first and second track elements are separated. In other words, the interface portions 210a, 21b of the first and second track elements 206, 208 still overlap in a direction perpendicular to their longitudinal direction when the first and second track elements are separated. This has the advantage that when the first and second track elements are separated, the wheels of the cargo handling device can still travel across their respective track surfaces. This is demonstrated in Figures 48 and 49, which show a parallel set of tracks in the form of a single elongated track element, and each track in the set of parallel tracks is equipped with the telescopic joint of the present invention to allow a pair of wheels at the front and rear of the cargo handling device to travel along the track. As a result of the offset arrangement of the gaps when the first and second track elements are separated, the wheels are constrained to the track surface by the guide surface, as demonstrated in Figure 49. As the wheel 36 moves on the track surface of the first track element 206, the wheel 36 is constrained by the guide surface 69a at the edge of the first track element 206. In addition, when the first and second track elements separate, the width of the track surface in the joint area where they meet is reduced, i.e., reduced by half so that only half the width of the wheel is supported on the reduced portion of the track surface. When the wheel reaches the edge of the track surface of the first track element 206 and approaches the gap 214a in the track surface, the constraint of the wheel on the track surface changes from the constraint by the guide surface 69a at the edge of the track element to the constraint by the central guide surface 69c as shown in Figure 49. Similarly, a wheel constrained by the central guide surface 69c is transitioned to being constrained by one of the outer guide surfaces 69a,b when the first and second track elements separate.

[0082] In this way, the wheels remain constrained on the track surface as they travel across the first and second track elements 206, 208, even when the first and second track elements are separated. Furthermore, the width of the track surface is reduced so that when the wheels of the cargo handling device move across the track surface of the second track element, only half the width of the wheels is supported by the track surface as they travel across the gap 214a. After crossing the gap in the junction region between the first and second track elements, the wheels of the cargo handling device are supported by the full width of the track surface.

[0083] A similar arrangement for restraining the wheels of a cargo handling device to their respective track surfaces when the first and second track elements separate is also demonstrated in Figures 24 to 27, where the first track element comprises a projecting male portion that is receivable within the receiving female portion of the second track element. This is not true with respect to the embodiment of the track element shown in Figure 23, where the bridging member comprises a separate bridging element providing two track surfaces 110a, 110b. When the first and second track elements separate, the bridging member 110 provides little restraint to the wheels on their respective track surfaces, increasing the risk that the wheels may derail from the track surfaces when the first and second track elements separate.

[0084] However, in contrast to the arrangement of the first and second track elements in the embodiments shown in Figures 24 to 27, the gaps 214a and 214b within the track surface are offset from each other longitudinally, so that when the first and second telescopic joints are arranged parallel to each other, the gap in the first telescopic joint 218a is always directly opposite the full track surface in the second telescopic joint 218b, and the second telescopic joint 218b is parallel to the first telescopic joint 218a. The wheels of the load handling device moving across the parallel first and second telescopic joints 218a and 218b encounter only one gap at any given time, rather than multiple gaps multiple times as in the embodiments shown in Figures 23 and 26. This reduces the amount of time the wheels get caught on or collide with the gaps, and further reduces the magnitude of the cronk noise phenomenon of the load handling device on the track. This configuration is contrasted with the telescopic joint configuration shown in Figures 23 and 26, in which the front wheels simultaneously encounter two gaps in the first and second telescopic joints, and the rear wheels simultaneously encounter two gaps, resulting in an increased level of wheel catching or collision in the load handling device, and further increasing the cronking phenomenon of the load handling device on the track. In the embodiment shown in Figures 48(a and b), the only opportunity for the front and rear wheels to encounter multiple gaps simultaneously is the gap 216 generated within the center of the track surface of the first and second track elements when the respective central guide surfaces 69c of those elements separate. The most important advantage of the embodiment shown in Figure 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.

[0085] To enable the first raceway element to pivot relative to the second raceway element, both raceway elements are supported on a sliding connection. Numerous examples of sliding connections according to the present invention exist. In the first example shown in Figure 50, the sliding connection 220 is similar to the raceway support element 56 discussed above with reference to Figure 10, but comprises back-to-back C sections 222, 224 arranged so that the raceway elements slide against each other within an overlapping joint area. The sliding connection within the overlapping joint area of ​​the raceway elements is provided by the arrangement of a slot 226 and a sliding bearing 228, in which one end of the C section has a slot that cooperates with a sliding bearing that connects the C sections together. In another example shown in Figure 51, the sliding section supporting the first and second raceway elements 206, 208 comprises a plate or bar 230. Both the first and second raceway elements 206, 208 have openings or recesses 232 for receiving the ends of the plate 230 in the sliding connection. In the particular embodiment shown in Figure 51, the first and second raceways 206, 208 are box sections for receiving the ends of the plate 230. One end of the plate is secured to the second raceway element using appropriate fasteners 234, such as bolts, screws, or pins, as shown in Figure 51, and the second end of the plate is receivable into a recess or opening 232 of the first raceway element 206. The surface of the plate, when received into its respective recess in the first and second raceway elements, supports the upper raceway contours of the first and second raceway elements from buckling under the weight of a load handling device moving along the raceway elements.

[0086] As with other embodiments discussed above, the expansion joints in the embodiments discussed with reference to Figures 46–51 can form part of a bridging joint assembly for connecting different regions of a grid structure as discussed above. Cap plates 158 for interconnecting adjacent upright members by track support elements supporting first and second track elements are shown in Figure 50. Here, the ends of the track support elements are connected to their respective cap plates used for fastening to the upright members. In addition, mechanical fuses may be used to connect the track supports to the upright members via the cap plates. If the track support elements are back-to-back C sections as shown in Figure 50, the mechanical fuses may be incorporated into a sliding bearing within the joint area where the back-to-back C sections overlap. Alternatively, the mechanical fuses may be incorporated into a fastener used to connect one of the track support elements to its respective cap plate.

[0087] Various modifications of exemplary embodiments that are 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 interconnect at least one of a plurality of upright members to a grid member via a cap plate, together with mechanical fuses used to connect the ends of adjacent grid members via a bridging joint assembly. The invention described in the original claims of this application is listed below. [1] A telescopic joint for connecting regions of a grid structure comprising a plurality of tracks, the first set of parallel tracks extending in a first direction and the second set of parallel tracks extending in a second direction, wherein the second set of parallel tracks extends substantially transversely to the first set of tracks in a substantially horizontal plane such that the plurality of tracks are arranged in a grid pattern comprising a plurality of grid cells, and each of the plurality of tracks has an upper surface contoured to provide two parallel track surfaces defining a double track for guiding two wheeled cargo handling devices, and the telescopic joint is, The track comprises a first track element and a second track element, each of the first and second track elements providing a portion of one of the plurality of tracks, the first and second track elements being elongated, and each of the first and second track elements having interface portions arranged to slide longitudinally relative to each other to provide a double track having two parallel track surfaces extending from the first track element to the second track element, suitable for guiding two wheeled cargo handling devices across the telescopic joint, Herein, the telescopic joint is positioned such that the interface portion of the second orbital element is substantially rotated 180° around the vertical axis of the interface portion of the first orbital element. [2] The telescopic joint according to [1], wherein each of the plurality of orbitals comprises a plurality of elongated orbital elements, and the first orbital elements and the second orbital elements are arranged to connect with each other at their respective interface portions to form a single elongated orbital element extending in either the first or second direction. [3] The upper surface of each of the first and second track elements is contoured to provide at least one guide surface of the track, the at least one guide surface is positioned to restrain a wheel of a load handling device on each of the two parallel track surfaces, as described in [1] or [2]. [4] The telescopic joint according to [3], wherein the at least one guide surface comprises a lip or ridge extending upward from each of the two parallel orbital surfaces. [5] The telescopic joint according to [3] or [4], wherein the at least one guide surface of the first orbital element is arranged in a closed configuration to abut against the at least one guide surface of the second orbital element in order to provide a continuous guide surface extending between the first orbital element and the second orbital element, and the first and second orbital elements are arranged in an open configuration to separate from each other in order to provide at least one gap in the two parallel orbital surfaces between the first and second orbital elements. [6] The telescopic joint according to [5], wherein the interface portion of each of the first and second track elements is formed having three steps configured to fit together in the closed configuration and separate in the open configuration. [7] The telescopic joint according to [5] or [6], wherein the at least one gap comprises two gaps offset from each other in the longitudinal direction. [8] The telescopic joint according to any one of [3] to [7], wherein the at least one guide surface comprises a first edge guide surface and a second edge guide surface that extend longitudinally along the outer edges of each of the first and second orbital elements, and a central guide surface that extends parallel to the first and second edge guide surfaces, wherein the area between the central guide surface and the first and second guide surfaces defines the two parallel orbital surfaces, and the first edge guide surface is longer than the second edge guide surface. [9] The telescopic joint according to any one of [1] to [8], further comprising a sliding connection for supporting the first and second raceway elements to enable the first and second raceway elements to slide toward each other in the longitudinal direction.

[10] The telescopic joint according to [9], wherein the sliding connection portion comprises overlapping track support elements arranged to slide relative to one another.

[11] The telescopic joint according to

[10] , wherein the overlapping raceway support elements are provided with slots and sliding bearing arrangements within the joint area where the raceway support elements overlap.

[12] The telescopic joint according to [9], wherein the sliding connection portion comprises a connecting element that can be slidably received within the openings in the first and second raceway elements.

[13] The telescopic joint according to

[12] , wherein the connecting element has a first end fixed within the opening of the first orbital element and an opposing second end positioned to be receivable within the opening of the second orbital element.

[14] The telescopic joint according to

[12] or

[13] , wherein each of the first and second orbital elements comprises a box section.

[15] A grid framework structure, The structure comprises multiple upright members, the multiple upright members being arranged to form multiple vertical spaces for one or more containers to be guided vertically by the upright members, Herein, the plurality of upright members are interconnected by a plurality of tracks comprising a first set of parallel tracks extending in a first direction and a second set of parallel tracks extending in a second direction, such that nodes are defined at their upper ends, the second set of parallel tracks passing transversely to the first set of tracks in a substantially horizontal plane to form the grid structure comprising a plurality of grid cells for the load handling device, which has a pair of wheels at the front and rear of the load handling device, to move on the grid structure, A portion of the first and / or second set of parallel tracks comprises first and second telescopic joints, each of the first and second telescopic joints comprising a telescopic joint as described in any one of [1] to

[14] , The first and second thermal expansion joints are arranged parallel to each other in a grid framework structure such that, during use, the pairs of front and rear wheels of the cargo handling device are constrained on their respective track surfaces as they move across the first and second thermal expansion joints.

[16] A storage and retrieval system, i) The grid framework structure described in

[15] , ii) Multiple stacks of containers arranged within storage columns located below the grid, where each storage column is positioned vertically below the grid cells, iii) A plurality of loading handling devices for lifting and moving containers stacked in the stack, and the plurality of loading handling devices being remotely operated to move laterally on the grid above the storage column to access the containers through the grid cells, and each of the plurality of loading handling devices, a) A wheel assembly for guiding the cargo handling device on the grid, b) A container receiving space located above the grid, c) comprising a lifting device positioned to lift a single container from the stack into the container receiving space, A storage and retrieval system equipped with the following features.

Claims

1. A telescopic joint for connecting regions of a grid structure comprising a plurality of tracks, the first set of parallel tracks extending in a first direction and the second set of parallel tracks extending in a second direction, wherein the second set of parallel tracks extends substantially transversely to the first set of tracks in a substantially horizontal plane such that the plurality of tracks are arranged in a grid pattern comprising a plurality of grid cells, and each of the plurality of tracks has an upper surface contoured to provide two parallel track surfaces defining a double track for guiding two wheeled cargo handling devices, and includes a lip and a central ridge or lip along the length of the two pairs of tracks, Each of the plurality of orbits comprises a plurality of elongated orbital elements, and the first orbital element and the second orbital element are arranged to connect with each other at their respective interface portions to form a single elongated orbital element extending in either the first or second direction. The aforementioned telescopic joint, The track comprises a first track element and a second track element, each of the first and second track elements providing a portion of one of the plurality of tracks, the first and second track elements being elongated, and each of the first and second track elements having interface portions arranged to slide longitudinally relative to each other to provide a double track having two parallel track surfaces extending from the first track element to the second track element, suitable for guiding two wheeled cargo handling devices across the telescopic joint, The upper surface of each of the first and second track elements is contoured to provide at least one guide surface of the track, the at least one guide surface is positioned to restrain the wheel of the load handling device on each of the two parallel track surfaces. The at least one guide surface comprises a first edge guide surface and a second edge guide surface that extend longitudinally along the outer edges of the respective first and second orbital elements, and a central guide surface that extends parallel to the first and second edge guide surfaces, thereby defining the two parallel orbital surfaces in the area between the central guide surface and the first and second guide surfaces. Herein, an extendable joint is positioned such that the interface portion of the second orbital element is substantially rotated 180° around the vertical axis of the interface portion of the first orbital element.

2. The telescopic joint according to claim 1, wherein the at least one guide surface comprises a lip or ridge extending upward from each of the two parallel track surfaces.

3. The telescopic joint according to claim 1, wherein the at least one guide surface of the first orbital element is arranged in a closed configuration to abut against the at least one guide surface of the second orbital element in order to provide a continuous guide surface extending between the first orbital element and the second orbital element, and the first and second orbital elements are arranged in an open configuration to separate from each other in order to provide at least one gap within the two parallel orbital surfaces between the first and second orbital elements.

4. The telescopic joint according to claim 3, wherein each of the interface portions of the first and second track elements is formed having three steps configured to fit together in the closed configuration and separate in the open configuration.

5. The telescopic joint according to claim 3, wherein the at least one gap comprises two gaps that are offset from each other in the longitudinal direction.

6. The expandable joint according to claim 1, wherein the first edge guide surface is longer than the second edge guide surface.

7. The telescopic joint according to claim 1, further comprising sliding connections for supporting the first and second raceway elements to enable the first and second raceway elements to slide relative to each other in the longitudinal direction.

8. The telescopic joint according to claim 7, wherein the sliding connection portion comprises overlapping track support elements arranged to slide relative to one another.

9. The telescopic joint according to claim 8, wherein the overlapping track support elements are provided with slots and sliding bearing arrangements within the joint area where the track support elements overlap.

10. The telescopic joint according to claim 7, wherein the sliding connection portion comprises a connecting element that can be slidably received within the openings in the first and second raceway elements.

11. The telescopic joint according to claim 7, wherein the connecting element has a first end fixed within the opening of the first track element and an opposing second end positioned to be receivable within the opening of the second track element.

12. The telescopic joint according to claim 10, wherein each of the first and second track elements comprises a box section.

13. It is a grid framework structure, The structure comprises multiple upright members, the multiple upright members being arranged to form multiple vertical spaces for one or more containers to be guided vertically by the upright members, Herein, the plurality of upright members are interconnected by a plurality of tracks comprising a first set of parallel tracks extending in a first direction and a second set of parallel tracks extending in a second direction, such that nodes are defined at their upper ends, and the second set of parallel tracks extends transversely to the first set of tracks in a substantially horizontal plane to form the grid structure comprising a plurality of grid cells for the load handling device, which has a pair of wheels at the front and rear of the load handling device, to move on the grid structure. A portion of the first and / or second set of parallel tracks comprises first and second telescopic joints, each of the first and second telescopic joints comprising a telescopic joint according to any one of claims 1 to 12. The first and second telescopic joints are arranged parallel to each other in a grid framework structure such that, during use, the pairs of front and rear wheels of the cargo handling device are constrained on their respective track surfaces as they move across the first and second telescopic joints.

14. A storage and retrieval system, i) The grid framework structure described in claim 13, ii) Multiple stacks of containers arranged within storage columns located below the grid, where each storage column is positioned vertically below the grid cells, iii) Multiple cargo handling devices for lifting and moving containers stacked within the stack, and the multiple cargo handling devices being remotely operated to move laterally on the grid above the storage columns to access the containers through the grid cells, each of the multiple cargo handling devices, a) A wheel assembly for guiding the cargo handling device on the grid, b) A container receiving space located above the grid, c) comprising a lifting device positioned to lift a single container from a stack into the container receiving space, A storage and retrieval system equipped with the following features.

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