Automated container loader

Abstract

To provide an automatic container loader for loading a small storage container into a larger storage container.SOLUTION: The loader includes a container support for receiving a larger storage container, and a container loading assembly configured to receive a smaller storage container above the larger storage container and release the smaller storage container to allow the smaller storage container to lower under gravity into the larger storage container. The container loading assembly also includes a plurality of engagement surfaces configured to engage the smaller storage container during at least a portion of a descent of the smaller storage container to control a rate of descent of the smaller storage container under gravity.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION The present invention relates to an automated device for loading smaller storage containers into larger storage containers in a storage and retrieval system. [Background technology]

[0002] Some commercial and industrial activities require a system that allows for the storage and retrieval of a large number of different products. WO2015019055A1 describes a storage and retrieval system in which a stack of storage containers is arranged in a grid storage structure. The storage containers are accessed from above by a load handling device operable on rails or tracks located on the top of the grid storage structure.

[0003] Prior to entering the grid storage structure, the storage containers are loaded with items for storage. For some products (especially perishable and chilled products), the items may be delivered by the supplier in crates, e.g., reusable plastic crates / containers (RPCs) such as those manufactured and supplied by IFCO Systems GmbH. To avoid the time and space costs of transferring items from the RPC to a storage container and storing the empty RPC until it can be returned to the supplier, the RPC and its items can be loaded directly into the storage container. The combined RPC and storage container can then be stored in the storage structure.

[0004] RPCs are typically loaded into storage containers by hand. To improve efficiency, it is desirable to automate the loading process. However, there are several challenges that must be overcome to enable the loading process to be automated reliably and efficiently.

[0005] These challenges include: The RPC must be loaded into the storage container without damaging the items inside the RPC. The size, weight, and center of gravity of each RPC can vary depending on the items in the RPC and the distribution of items within the RPC. An automated system would ideally accommodate different variations in these variables so that each RPC is loaded in a stable and reliable manner. The dimensions of the RPC and the storage container may be similar, with only a small gap (e.g., a few millimeters) between the side walls of the RPC and the side walls of the storage container, which limits the space available for the container handling mechanism. The size of the opening or cavity of a storage container may not be consistent, even among storage containers originally manufactured to be the same size. This is because the side walls of a storage container may warp (e.g., bend inward) over time. The warped side walls may reduce the size of the opening or cavity of the storage container sufficiently that the side walls prevent the insertion of RPCs into the storage container. External features of RPCs (e.g., protrusions, recesses, openings, etc.) vary depending on the manufacturer and product line. An automated system would ideally handle RPCs with different external features in a reliable and repeatable manner.

[0006] Therefore, there is a need for an apparatus that can automate the efficient, reliable, and repeatable loading of smaller containers (such as RPCs) into larger storage containers while minimizing the risk of damaging items within the smaller containers. Summary of the Invention

[0007] The invention is defined in the appended claims.

[0008] Automatic Container Loader An automated container loader is provided for loading smaller storage containers into larger storage containers. The automated container loader comprises: a container support for receiving a larger storage container; a container stowage assembly configured to receive a smaller storage container above a larger storage container and release the smaller storage container to allow the smaller storage container to descend under gravity into the larger storage container; and the container stowage assembly comprises a plurality of engagement surfaces configured to engage the smaller storage container during at least a portion of the descent of the smaller storage container to control the rate of descent of the smaller storage container under gravity.

[0009] By providing an engagement surface that engages the smaller storage container during its descent into the larger storage container, the rate of descent of the smaller storage container can be reduced, thereby reducing the impact force between the smaller and larger storage containers at the end of the descent of the smaller storage container. This is particularly useful in situations where the smaller storage container holds fragile goods that could be damaged if the impact force between the smaller and larger storage containers is too high.

[0010] The container stowage assembly may include a trapdoor comprising at least two door panels. Each door panel may define one of a plurality of engagement surfaces. Each door panel may be pivotally mounted for rotation about a respective horizontal pivot axis. The door panels may be pivotally rotatable downward from a substantially horizontal initial position for receiving a smaller storage container above a larger storage container to a final position for allowing the smaller storage container to be lowered between the pivot axes under gravity into the larger storage container. The container stowage assembly may further include a control system comprising a controller configured to control the pivotal rotation of the door panels between the initial and final positions such that the door panels frictionally engage the smaller storage container during at least a portion of the smaller storage container's descent under gravity to control the rate of descent of the smaller storage container under gravity.

[0011] The trapdoor may have two door panels with their respective pivot axes parallel to one another and in the same horizontal plane. The pivot axes may be spaced apart so that the door panels can rotate past one another without colliding. Each pivot axis may be defined by the longitudinal axis of a rotatable shaft. Each door panel may be rigidly mounted to its respective rotatable shaft.

[0012] The controller may be configured to control the pivotal rotation of the door panel such that the door panel frictionally engages (via sliding contact) with a respective side wall of the smaller storage container during a portion of the descent of the smaller storage container.

[0013] The door panel may be stoppable at at least one intermediate angular position between the initial position and the final position. The door panel may be stoppable at any one of a plurality of intermediate angular positions between the initial position and the final position. The door panel may be pivotally rotatable upward from one of the plurality of intermediate angular positions to another of the plurality of intermediate angular positions. In this manner, the angular position of the door panel can be fine-tuned during descent of the smaller storage container to increase or decrease frictional engagement between the door panel and the smaller storage container, which will respectively decrease or increase the descent speed of the smaller storage container.

[0014] The controller may use closed-loop control during a portion of the descent of the smaller storage container. The control system may further include at least one displacement sensor configured to measure vertical displacement of the smaller storage container during a portion of the descent of the smaller storage container. The displacement sensor may be located above the trapdoor. The controller may be configured to control the angular position of the door panel based on displacement measurements from the at least one displacement sensor.

[0015] For example, the controller may be configured to determine a descent speed and / or acceleration of the smaller storage container based on measurements from at least one displacement sensor. The controller may be configured to control the angular position of the door panel to keep the descent speed and / or acceleration of the smaller storage container below a maximum speed and / or acceleration threshold. The maximum descent acceleration threshold may be approximately 9.8 m / s 2 may be the gravitational acceleration.

[0016] The controller may be configured to pivotally rotate the door panel upward when the descent speed of the smaller storage container exceeds a predetermined maximum speed and / or acceleration threshold. Rotating the door panel upward may increase frictional engagement between the door panel and the smaller storage container, thereby reducing the descent speed and / or acceleration below the maximum speed and / or acceleration threshold.

[0017] The controller may be further configured to pivotally rotate the door panel downward when the descent speed and / or acceleration of the smaller storage container is below a minimum speed and / or acceleration threshold. Rotating the door panel downward may reduce frictional engagement between the door panel and the smaller storage container, thereby increasing the descent speed and / or acceleration above the minimum speed and / or acceleration threshold.

[0018] The control system may include a plurality of displacement sensors configured to measure vertical displacement of different portions of the smaller storage container during descent of the smaller storage container. The plurality of displacement sensors may be located above the trap door. For example, the plurality of displacement sensors may be positioned above the trap door to measure vertical displacement of each corner of the smaller storage container. The controller may be configured to determine an orientation of the smaller storage container relative to a horizontal plane based on measurements from the plurality of displacement sensors. The controller may be configured to interrupt pivotal rotation of the door panel when the controller determines that the smaller storage container is tilted away from a horizontal plane by a predetermined degree.

[0019] The control system may include a plurality of displacement sensors configured to measure vertical displacement of different portions of the smaller storage container during descent of the smaller storage container. The plurality of displacement sensors may be located above the trap door. The plurality of displacement sensors may be positioned above the trap door, for example, to measure vertical displacement of each corner of the smaller storage container. The controller may be configured to determine an orientation of the smaller storage container relative to a horizontal plane based on measurements from the plurality of displacement sensors. The controller may be configured to control the angular position of each door panel to maintain a substantially horizontal orientation of the smaller storage container during descent of the smaller storage container.

[0020] The controller may use open-loop control during a portion of the descent of the smaller storage container. The controller may be configured to pivotally rotate the door panel between an initial position and a final position according to a predetermined motion profile. The predetermined motion profile may be selected such that the door panel is rotated downward at a rate such that the door panel frictionally engages the smaller storage container during a portion of the descent of the smaller storage container.

[0021] The controller may be configured to control the pivotal rotation of the door panel to stop the descent of the smaller storage container at an intermediate lowered position above the final lowered position. The container stowage assembly may further include a pushing device configured to push the smaller storage container downwardly from the intermediate lowered position to the final lowered position at a predetermined speed.

[0022] The door panels may be elastically flexible. In other words, the door panels may flex when under load from the smaller storage container (particularly when the door panels are in frictional engagement with the side walls of the smaller storage container) and return to their pre-deflected state when the load is removed. This may increase the surface area contact between the door panel and the smaller storage container, which may result in a more reliable frictional engagement between the door panel and the smaller storage container and may also spread wear on the door panel over a larger surface area.

[0023] Each door panel may be divided along a direction perpendicular to the horizontal pivot axis to define a first door panel portion and a second door panel portion. The first and second door panel portions may be pivotally rotatable together about their respective door panel pivot axes. The first and second door panel portions may be independently resiliently flexible. Such a divided door panel configuration may be used to load first and second smaller storage containers having different sizes and / or weights side-by-side into a larger storage container. The controller may be configured to control the angular position of the door panel according to the smaller storage container descending fastest. Alternatively, each door panel portion may be independently pivotally rotatable about its respective door panel pivot axis to independently control the descent speed of the first and second smaller storage containers.

[0024] Each door panel may include a mounting end to which the door panel is pivotally mounted and a free end opposite the mounting end. Each free end may have a castellation configuration. The door panels may be arranged so that the castellations at the free ends interlock with each other when the door panels are in a horizontal initial position. In this manner, the width of each door panel (the distance between the mounting end and the free end) may be extended further than would be possible without the interlocking castellations, which allows each door panel to remain in frictional engagement with the smaller storage container over a greater distance during descent of the smaller storage container.

[0025] The door panels may be configured to pivotally rotate in unison. The container stowage assembly may include a single actuator configured to pivotally rotate the door panels in unison. The actuator may be controlled by a controller to control the angular position of the door panels. For example, the door panels may be mechanically coupled to a common guided carriage arranged to move up and down along vertical guides. The guided carriage may be driven by the actuator along the vertical guides such that the door panels are pivotally rotated upward or downward in unison.

[0026] The door panels may be pivotally rotatable independently of one another, and the controller may be configured to control the angular positions of the door panels independently of one another, for example, each door panel may be pivotally rotated by a separate actuator.

[0027] The container stowage assembly may further include guide members above the trapdoor. The guide members may be configured to engage with side walls of each of the smaller storage containers to guide the smaller storage containers into symmetrical positions on the door panel. Alternatively or additionally, the guide members may engage with side walls of each of the smaller storage containers to help maintain a vertical orientation of the smaller storage containers during at least a portion of their descent into the larger storage container.

[0028] The container support and trapdoor may be vertically movable relative to one another so that pivotal rotation of the door panel from an initial position to a final position allows the larger storage container and door panel to be moved into relative positions that rotate the door panel into the larger storage container. The container support may be vertically movable relative to the trapdoor, or the trapdoor may be vertically movable relative to the container support. This minimizes or eliminates the amount of time the smaller storage container free-falls before reaching the base of the larger storage container, which helps reduce impact forces between the smaller and larger storage containers. Furthermore, if any of the side walls of the larger storage container bow inward (due to wear, etc.), the pivotal rotational movement of the door panel relative to the side walls of the larger storage container can be used to push the bowed sidewall outward, thereby allowing the smaller storage container to descend more easily.

[0029] method A method for automated loading of a smaller storage container into a larger storage container is provided, the method comprising: receiving a smaller storage container on a trapdoor above the larger storage container, the trapdoor having at least two pivotally mounted door panels in a horizontal initial position for receiving the smaller storage container; Pivotally rotating the door panel downward to allow the smaller storage container to descend between the door panels under gravity into the larger storage container; and controlling the pivotal rotation of the door panel during the descent of the smaller storage container such that the door panel frictionally engages the smaller storage container during at least a portion of the descent.

[0030] The pivoting of the door panel may be controlled so that the door panel frictionally engages the side walls of each of the smaller storage containers during a portion of the descent.

[0031] The pivotal rotation of the door panel can be controlled so that the door panel contacts the smaller storage container throughout its descent into the larger storage container.

[0032] The method comprises: measuring vertical displacement of the smaller storage container during lowering of the smaller storage container into the larger storage container; calculating a descent rate and / or acceleration of the smaller storage container based on the vertical displacement measurements; and controlling the angular position of the door panel during descent of the smaller storage container to keep the descent speed and / or acceleration of the smaller storage container below a maximum speed threshold.

[0033] The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which like reference numerals are used to refer to like features, and in which: [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is a perspective view of an automated container loader showing a smaller storage container and a larger storage container approaching a container stowage assembly and a container support, respectively. [Figure 2] FIG. 2 is a perspective view of the container stowage assembly shown in FIG. 1. [Figure 3] 2 is a perspective view of the automated container loader of FIG. 1 showing a smaller storage container on the container loading device and a larger storage container on the container support. FIG. [Figure 4] 4 is a perspective view of the automated container loader in a state subsequent to FIG. 3, in which the container support has lifted the larger storage container toward the container stowage assembly. [Figure 5] 5 is a perspective view of the automated container loader in a state subsequent to FIG. 4, in which the container loading assembly has dropped a smaller storage container into a larger storage container. [Figure 6]6 is a perspective view of the automated container loader in a state subsequent to FIG. 5, in which the container support has lowered the loaded larger storage container away from the container stowage assembly. [Figure 7] 7 is a perspective view of the automatic container loader in a state subsequent to FIG. 6, in which the loaded larger storage container is leaving the automatic container loader. [Figure 8A] 2 is a series of cross-sectional side views of the automated container loader of FIG. 1 illustrating the lowering of a smaller storage container into a larger storage container using a container stowage assembly. [Figure 8B] 2 is a series of cross-sectional side views of the automated container loader of FIG. 1 illustrating the lowering of a smaller storage container into a larger storage container using a container stowage assembly. [Figure 8C] 2 is a series of cross-sectional side views of the automated container loader of FIG. 1 illustrating the lowering of a smaller storage container into a larger storage container using a container stowage assembly. [Figure 8D] 2 is a series of cross-sectional side views of the automated container loader of FIG. 1 illustrating the lowering of a smaller storage container into a larger storage container using a container stowage assembly. [Figure 8E] 2 is a series of cross-sectional side views of the automated container loader of FIG. 1 illustrating the lowering of a smaller storage container into a larger storage container using a container stowage assembly. [Figure 9A] 10 is a graph showing the angular position of a door panel of a container stowage assembly versus time as a smaller storage container is stowed into a larger storage container. [Figure 9B] 10 is a graph showing vertical displacement of a smaller storage container versus time as the smaller storage container is being stowed into a larger storage container using a container stowage assembly. [Figure 10] FIG. 1 is a schematic block diagram of a control system for controlling the door panels of a container stowage assembly. [Figure 11]FIG. 1 is a perspective view of a container stowage assembly with a pushing device. [Figure 12] FIG. 1 is a perspective view of a container stowage assembly receiving two smaller storage containers positioned side by side. [Figure 13] FIG. 1 is a perspective view of a trapdoor in which each of the door panels of the trapdoor is divided into two parts. [Figure 14] 1 shows a top view comparing a trapdoor with castellations that allow the door panels of the trapdoor to interlock with each other and a trapdoor without castellations. [Figure 15] 15A and 15B show side cross-sectional views comparing the castellated trapdoor of FIG. 14 with the non-castellated trapdoor when in a vertical position extending into a storage container. [Figure 16] FIG. 1 is a perspective view of a grid storage structure. DETAILED DESCRIPTION OF THE INVENTION

[0035] 1 shows an automated container loader 100 for loading smaller storage containers 80 into larger storage containers 90. The automated container loader 100 may be part of a storage and retrieval system in which the larger storage containers 90 are used to store items for later retrieval. As described in the Background section above, the smaller storage containers 80 loaded by the automated container loader 100 may be in the form of reusable plastic containers (RPCs), such as those manufactured and supplied by IFCO Systems GmbH. The purpose of the automated container loader 100 is to load one or more smaller storage containers 80 directly into the larger storage container 90 before the larger storage container 90 is transported to a storage area of ​​the storage and retrieval system.

[0036] Both the smaller storage container 80 and the larger storage container 90 have a rectangular base with four side walls 82, 92 extending from the base and defining an opening at the top. The smaller storage container 80 has a smaller horizontal dimension than the larger storage container 90 so that the smaller storage container 80 can be placed and stored in the larger storage container 90 through the top opening of the larger storage container 90. Either or both of the smaller and larger storage containers 80, 90 may be foldable, e.g., one or more side walls 82, 92 may be foldable relative to the base.

[0037] The automated container loader 100 includes a container stowage assembly 110 configured to receive smaller storage containers 80. The smaller storage containers 80 reach the container stowage assembly 110 via a conveyor unit 101, but may also reach the container stowage assembly 110 via other automated or manual transport means. The container stowage assembly 110 and conveyor unit 101 may be mounted on a frame (not shown for clarity).

[0038] The container stowage assembly is shown in isolation in Figure 2. The container stowage assembly 110 includes a trapdoor 111. The trapdoor 111 includes two rectangular door panels 112, each having a mounting end 113 and a free end 114 opposite the mounting end 113. The mounting end 113 of each door panel 112 is rigidly mounted to a respective horizontal shaft 120 that is rotatable about its longitudinal axis 121. Thus, each door panel 112 is rotatable about a horizontal pivot axis 121 that corresponds to the longitudinal axis 121 of its respective shaft 120. The shafts 120 are disposed parallel to each other and lie in the same horizontal plane. The shafts 120 are also spaced apart to allow the free ends 114 of the door panels to rotate past each other without collision.

[0039] 1 and 2 show the trapdoor 111 in a closed configuration, with the door panels in a horizontal initial position and the free ends 114 pointing toward each other. Together, the door panels form a substantially horizontal, upward-facing surface for receiving a smaller storage container 80. FIG. 3 shows the smaller storage container 80 received on the upward-facing surface of the trapdoor 111. The upward-facing surfaces need not be touching, as a gap may exist between the free ends 114 of the door panels when the trapdoor 111 is in the closed configuration. The widths of the door panels 112 (defined as the distance between the mounting end 113 and the free end 114) are substantially the same, such that the door panels are symmetrically disposed about a centerline running parallel between the two pivot axes 121.

[0040] To open the trapdoor 111, the door panel is pivotally rotated downward from a horizontal position to a vertical final position, creating a gradually wider opening below the smaller storage container 80 that allows the smaller storage container 80 to descend through the trapdoor 111 between the shafts 120.

[0041] Both door panels are mechanically coupled via linkage arms 124 and joints 125 to a common guided carriage 123 that is centered about pivot axis 121 at one end of trapdoor 111. Guided carriages 123 are arranged to move up and down along vertical guides 122. Linkage arms 124 and joints 125 are configured such that when guided carriages 123 move up vertical guides 122, the door panels pivotally rotate upward in unison, and when guided carriages 123 move down vertical guides 122, the door panels pivotally rotate downward in unison. The vertical position of guided carriages 123 along vertical guides 122 is controlled by an electric linear actuator 126, such as a slide screw actuator. The linear actuator 126 enables the guided carriage 123 to move and stop at any one of a plurality of positions along the vertical guide 122, so that the door panel can pivotally rotate to and stop at any one of a plurality of intermediate angular positions between the initial position and the final position.

[0042] The container stowage assembly 110 further includes side guides 119 located above the door panel. The side guides 119 are in the form of two vertical panels horizontally opposed to each other and aligned parallel to the direction in which the smaller storage container 80 moves onto the trap door 111. One purpose of the side guides 119 is to help center the smaller storage container 80 on the closed trap door 111 so that the smaller storage container 80 is symmetrically disposed on the door panel. Another purpose of the side guides 119 is to help maintain a vertical orientation of the smaller storage container 80 as it is lowered into the larger storage container 90 (i.e., the side guides 119 help prevent the smaller storage container 80 from tipping to one side during descent). In one example, the side guides 119 may be configured to move toward each other when a smaller storage container 80 is received onto the trapdoor 111, such that the position of the smaller storage container 80 is adjusted by the side guides 119 toward a central position on the trapdoor 111. This would also allow the container stowage assembly 110 to be used for smaller storage containers 80 of different widths. In another example, the side guides 119 may be fixed symmetrically about the centerline of the trapdoor 111, and each side guide 119 may include a tapered portion to form a tapered opening for guiding the smaller storage container 80 into the correct position between the side guides 119 as the smaller storage container 80 is moved onto the trapdoor 111.

[0043] The smaller storage containers 80 may be transferred from the conveyor unit 101 to the trap door 111 using any suitable transfer mechanism. For example, the automated container loader 100 may include a pusher member that pushes the smaller storage containers 80 horizontally from the conveyor unit 101 onto the trap door 111, or a gripping device that grips the smaller storage containers 80 on the conveyor unit 101, moves the smaller storage containers 80 horizontally onto the trap door 111, and then releases them.

[0044] The automated container loader 100 further includes a container support 130 for receiving the larger storage container 90 directly below the trapdoor 111 of the container drop assembly, as shown in FIG. 3 . The larger storage container 90 arrives at the container support 130 via a conveyor unit 102 or other transport means. The container support 130 includes a platform 132 for receiving the larger storage container 90. Similar to the container stowage assembly 110, the container support 130 may include side guides or other positioning means for positioning the larger storage container at a specific location on the platform 132. The platform 132 may be in the form of a separate conveyor unit to facilitate movement of the larger storage container 90 onto and off the platform 132, or a transport mechanism similar to that described above (with respect to the conveyor unit 101 and trapdoor 111) may be provided for transporting the larger storage container 90 onto and off the platform 132. 4, the container support 130 further includes a lifting mechanism 134 configured to raise and lower the platform 132 to vertically move the larger storage container 90 toward and away from the trapdoor 111, respectively. In particular, the lifting mechanism 134 is configured to vertically move the larger storage container 90 between a lowered release position (the position shown in FIG. 3) and a raised stowage position (the position shown in FIG. 4).

[0045] 5 shows the larger storage container 90 in the raised stowage position with the trap door 111 open. In the raised stowage position, the larger storage container 90 is positioned vertically relative to the trap door 111 so that the trap door 111 opens into the larger storage container 90, i.e., so that at least a portion of each door panel 112 enters the cavity (defined by the base and side wall 92) of the larger storage container 90 when the door panels are pivotally rotated downward from a horizontal position. The stowage position is used when a smaller storage container 80 is being stowed into the larger storage container 90. This has the following advantages: First, the descent of the smaller storage container 80 can be controlled by the door panel while the smaller storage container 80 is within the larger storage container 90. This minimizes or eliminates the amount of time the smaller storage container 80 free-falls before reaching the base of the larger storage container 90, which helps reduce impact forces between the smaller storage container 80 and the larger storage container 90. Second, while the side walls 92 of the larger storage container 90 are generally substantially vertical when initially manufactured, through continued use, one or more side walls may bow inward due to wear. The inwardly bowed side walls may reduce the interior dimensions of the larger storage container 90, thereby preventing a smaller storage container 80 from fully entering the larger storage container 90 unless a downward force is applied to the smaller storage container 80. By opening the trapdoor 111 into the larger storage container 90, the door panel may push any inwardly bowed side walls outward, thereby allowing the smaller storage container 80 to enter the larger storage container 90 under gravity without having to be pushed.

[0046] When the larger storage container 90 is in the loading position with the trapdoor 111 open and the smaller storage container 80 is fully loaded into the larger storage container 90, the door panel is located in the space between the sidewall 82 of the smaller storage container 80 and the sidewall 92 of the larger storage container 90. This arrangement prevents the loaded larger storage container 90 from moving horizontally away from the automatic container loader 100 and prevents the trapdoor 111 from closing to receive the next smaller storage container 80. Thus, after the larger storage container 90 is loaded with the smaller storage container 80, the larger storage container 90 is lowered to the release position.

[0047] Figure 6 shows the loaded larger storage container 90 in the lowered, released position with the trap door 111 open. In the lowered, released position, the larger storage container 90 is vertically clear of the door panel, which allows the loaded larger storage container 90 to be transported away from the container support 130 and away from the automated container loader 100 via the conveyor unit 103 or other transport means without obstruction from the door panel. Figure 7 shows the loaded larger storage container 90 on the conveyor unit 103 after it has left the container support 130. The released position also allows the door panel to rotate back to a horizontal position to repeat the loading process with a new set of smaller and larger storage containers 80, 90.

[0048] 3, it can be seen that the container supports 130 are in the release position when receiving an empty larger storage container 90 from the conveyor unit 102. However, either the loading position or the release position may be used to receive an empty larger storage container 90 (with appropriate adjustments to the position of the conveyor unit 102), with the container supports 130 moving to other positions as needed during operation.

[0049] 8A-8E are a series of cross-sectional views of automated container loader 100 taken along a plane extending vertically through pivot axis 121 of door panel 112 and toward vertical guide 122. Figures 8A-8E show the relative positions of smaller storage container 80, door panel, and larger storage container 90 at various stages during the process of loading smaller storage container 80 into larger storage container 90.

[0050] 8A shows the trapdoor 111 closed with the door panel 112 in a horizontal position. The smaller storage container 80 is positioned symmetrically on top of the door panel so that it straddles the centerline between the two pivot axes 121 and is supported from below by both door panels 112. The larger storage container 90 sits on the container support platform 132 and is in a stowed position directly below the trapdoor 111.

[0051] 8B, the door panel 112 has begun to pivotally rotate downwards such that the trapdoor 111 is partially open. At this point, the vertical displacement of the smaller storage container 80 is negligible because the bottom edge of the smaller storage container 80 is still supported by the portion of the door panel 112 near the pivot axis 121.

[0052] In Figure 8C, the door panel 112 has been rotated further downward from the position in Figure 8B. At this point, the opening between the door panels 112 is wide enough that the smaller storage container 80 is no longer supported from below by the door panel 112. However, the opening between the door panels 112 is still slightly narrower than the width of the smaller storage container 80 so that the "upward" facing surfaces of the door panels 112 (which previously received the smaller storage container 80 when the door panel 112 was in a horizontal position) frictionally engage (i.e., slide against) the outer surfaces of the side walls 82 on each side of the smaller storage container 80. The frictional forces between the door panels and the side walls 82 of the smaller storage container 80 counteract the force of gravity acting on the smaller storage container 80, slowing the descent of the smaller storage container 80 under gravity into the larger storage container 90.

[0053] 8D, the smaller storage container 80 has completed its descent by contacting the base of the larger storage container 90. The smaller storage container 80 is now loaded into the larger storage container 90. At this point, the door panel 112 is still in contact with the smaller storage container 80.

[0054] 8E, the door panel 112 has been rotated to a vertical position (90 degrees downward from horizontal), in which the door panel 112 disengages from the side wall 82 of the smaller storage container 80, allowing the loaded larger storage container 90 to be lowered to the release position without the possibility of the door panel 112 pulling the smaller storage container away from the larger storage container.

[0055] FIG. 9A is a graph showing an example of how the angular position (θ) of one of the door panels 112 changes over time (t). In this example, the door panels 112 rotate in unison, so a graph of the angular position of the other door panel 112 over time would look similar. The graph shows the door panel 112 starting in a horizontal position (θ=0 at t=0) and ending in a vertical position (θ=−90° at t=T). FIG. 9B is a graph showing how the vertical displacement (x) of the smaller storage container 80 changes over the same time period as the graph of FIG. 9A, starting from a position at the top of the closed trapdoor 111 (x=0 at t=0) and ending with the smaller storage container 80 at the bottom of the larger storage container 90 (x=−D at t=T).

[0056] 10 shows a block diagram of an illustrative control system for controlling the angular position of door panel 112 during at least a portion of the sequence described above. The control system includes a controller 127 and a displacement sensor 128 located above trapdoor 111 for measuring the vertical displacement of smaller storage container 80 as it is lowered into larger storage container 90. Displacement sensor 128 can be any suitable type of displacement sensor, for example, an optical, ultrasonic, or laser displacement sensor. Controller 127 controls linear actuator 126 in response to measurements from displacement sensor 128 to control the angular position of door panel 112.

[0057] 9A and 9B, the controller 127 controls the linear actuator 126 according to three control regimes C1, C2, and C3 that operate at different time periods. The first control regime C1 (hereinafter referred to as the "support" control regime) operates during the time period up to time T1 when the bottom of the smaller storage container 80 is still supported from below by the door panel 112 (e.g., as shown in FIG. 8B). The second control regime C2 (hereinafter referred to as the "friction" control regime) operates during the time period between T1 and T2 when the door panel 112 no longer supports the smaller storage container 80 from below and is now in frictional engagement with the sidewall 82 of the smaller storage container 80 (e.g., as shown in FIG. 8C). A third control regime C3 (hereinafter referred to as the "release" control regime) operates during the time period between T2 and T3 to disengage the door panel 112 from the smaller storage container 80 after the smaller storage container 80 is fully received into the larger storage container 90 (e.g., as shown in FIG. 8E).

[0058] During the support control regime C1, the vertical displacement of the smaller storage container 80 will generally be small or negligible, especially if the distance between the pivot axes 121 of the door panels 112 is similar to the width of the smaller storage container 80. This is because the portion of the door panel 112 that supports the bottom edge of the smaller storage container 80 is close to the pivot axis 121 and therefore does not experience a large vertical displacement as the door panel 112 rotates downward from a horizontal position. The support control regime may be open loop, as the door panel 112 is allowed to rotate downward at a predetermined rate until the friction control regime begins.

[0059] During friction control regime C2, smaller storage container 80 slides vertically between door panels 112 under gravity, and therefore the rate at which smaller storage container 80 descends depends on the weight of smaller storage container 80 and the opposing frictional forces between door panels 112 and side walls 82 of smaller storage container 80. In friction control regime C2, controller 127 and displacement sensor 128 form part of a closed-loop control system. In particular, controller 127 calculates the downward velocity and / or acceleration of smaller storage container 80 each time displacement sensor 128 measures the displacement of smaller storage container 80 (which may be several times per second, depending on the sampling rate of displacement sensor 128). Controller 127 then adjusts the angular position of door panels 112 about their respective pivot axes 121 to keep the velocity and / or acceleration of smaller storage container 80 below predetermined maximum velocity and / or acceleration thresholds. In particular, if the velocity and / or acceleration of the smaller storage container 80 at a particular time is greater than a predetermined maximum velocity and / or acceleration threshold, the controller 127 pivotally rotates the door panel 112 upward to increase the frictional force between the door panel 112 and the smaller storage container 80 until the velocity and / or acceleration of the smaller storage container 80 falls below the maximum velocity and / or acceleration threshold. An illustrative maximum downward acceleration threshold is approximately 9.8 m / s 2 The controller 127 may also pivotally rotate the door panel downward to reduce frictional forces and allow the velocity and / or acceleration of the smaller storage container 80 to increase if the velocity and / or acceleration of the smaller storage container 80 decreases below a predetermined minimum velocity and / or acceleration threshold.

[0060] At the transition point between the support regime C1 and the friction regime C2, the smaller storage container 80 may suddenly begin to slip. The controller 127 may therefore determine the C1-C2 transition point by detecting when the velocity and / or acceleration of the smaller storage container 80 exceeds a predetermined transition velocity and / or acceleration threshold. Alternatively, a suitable C1-C2 transition point may be determined by trial and error experiments performed before the automated container loader 100 is produced.

[0061] After the smaller storage container 80 reaches the bottom of the larger storage container 90, the controller 127 in the release control regime C3 pivotally rotates the door panel 112 downward from their position at the end of the friction control regime C2 to a substantially vertical position so that the door panel 112 is no longer in contact with the smaller storage container 80. The release control regime can be open loop because there is no movement of the smaller storage container 80 and the door panel 112 only needs to move to a predetermined angular position (in this case, a vertical position).

[0062] The controller 127 can determine the transition point between the friction regime C2 and the release regime C3 by detecting, via measurements from the displacement sensor, when the smaller storage container 80 drops a known vertical distance corresponding to the vertical distance between the base of the smaller storage container 80 when it is on the closed trapdoor 111 and the base of the larger storage container 90 when it is in the stowed position. Alternatively, if the weight of the smaller storage container 80 is known, the C2-C3 transition point can be determined by including a weight scale in the container support 130 and detecting when the weight of the larger storage container 90 increases by the weight of the smaller storage container 80. Alternatively, a sensor located at or near the base of the larger storage container 90 can be used, although if the sensor is external to the larger storage container 90, this may require an aperture to be provided through the sidewall 92 of the larger storage container 90 so that the sensor can detect the presence of the smaller storage container 80 inside the larger storage container 90.

[0063] To reduce the cycle time of the loading operation, the time spent in each control regime can be optimized. For example, the time spent in the support control regime can be relatively short compared to the time spent in the friction regime (by rotating the door panel 112 downward relatively quickly) because there is no risk of the smaller storage container free falling during the support control regime. Similarly, the time spent in the release regime can also be relatively short compared to the time spent in the friction regime because the smaller storage container 80 is already fully loaded into the larger storage container 90 at the end of the friction regime C2.

[0064] The closed-loop friction control regime described above is advantageous because it allows the container loading assembly 110 to accommodate smaller storage containers 80 of different sizes and weights without prior knowledge of the size and weight of the smaller storage containers 80. Furthermore, the cycle time of the automated container loading can be optimized to a greater extent compared to an open-loop control system. However, if the automated container loader 100 is designed to load smaller storage containers 80 of a particular size and / or weight (or within a particular size and / or weight range), or if the automated container loader 100 is configured to determine the size and / or weight of the smaller storage container 80 before it is received on the trapdoor 111, the controller 127 may alternatively use an open-loop friction control regime. For example, the controller 127 may be configured to pivotally rotate the door panel 112 downward from a horizontal position to a vertical position using a predetermined motion profile. The predetermined motion profile may be a single motion profile designed to be used with smaller storage containers 80 of a particular size and / or weight, so that they do not exceed a predetermined maximum speed and / or acceleration threshold during descent. Alternatively, the predetermined motion profile may be one of multiple predetermined motion profiles selected depending on the size and / or weight of the smaller storage container 80. The predetermined motion profile may be developed based on previous testing conducted with smaller storage containers 80 of different sizes and weights. The size and / or weight of the smaller storage containers 80 may be determined before the smaller storage containers 80 are received on the trapdoor 111, for example, using appropriate sensors / machine vision and scales, or the size and weight of each smaller storage container 80 may be associated with a unique identifier (e.g., a QR code or RFID tag) on ​​the smaller storage container 80 that is read at the automated container loader 100 by an appropriate reader in communication with the controller 127.

[0065] 8A-8D show the door panel 112 remaining rigid throughout the process, the door panel 112 may be flexible such that the free end elastically flexes against the fixed end under load from the smaller storage container 80, particularly during the friction regime. This may result in an increased contact area between the door panel 112 and the sidewall 82 of the smaller storage container 80 during the friction control regime, which may help spread wear on the door panel 112 over a larger area. The return force applied to the smaller storage container 80 due to the elastic deformation of the door panel 112 may also help resist gravity acting on the smaller storage container 80.

[0066] Considering the high loads that may be experienced by the door panel 112 when engaged with the smaller storage container 80, and the frequent sliding contact between the door panel 112 and the smaller storage container 80 during use, the door panel 112 is preferably made from any suitable material having high yield strength and wear resistance, such as a metal (e.g., stainless steel) or a composite material (e.g., carbon fiber).

[0067] 11 shows an example of a container stowage assembly 110 that further includes a pushing device 140 mounted above the trap door 111. The pushing device 140 includes a horizontally oriented pushing plate 142 that is wide enough to engage the top of the smaller storage container 80 and a linear actuator 144 for vertically moving the pushing plate 142 relative to the trap door 111. In this example, the smaller storage container 80 does not reach the bottom of the larger storage container 90 under the influence of gravity alone. Instead, the door panel 112 is rotated downward to an angular position above the base of the larger storage container 90 such that the smaller storage container 80 is held substantially stationary by the door panel 112. The pushing device 140 then moves the pushing plate 142 downward to push the smaller storage container 80 the rest of the way into the larger storage container 90 until it reaches the bottom of the larger storage container 90. The door panel 112 remains in the same angular position while the pushing device 140 is actuated so that the smaller storage container 80 is pushed past the door panel 112. This example is therefore particularly suitable for door panels 112 that can resiliently deflect under load, as already explained above. The pushing device 140 can be configured to push down on the smaller storage container 80 at a predetermined speed such that the smaller storage container 80 does not exceed a predetermined maximum velocity and / or acceleration threshold in order to minimize the impact force between the smaller storage container 80 and the larger storage container 90 when they come into contact.

[0068] The automated container loader 100 can also be used to load multiple smaller storage containers 80 into a single larger storage container 90. As shown in FIG. 12 , two smaller storage containers 80 can be received side-by-side onto the trapdoor 111 such that they are each supported from below by both door panels 112. The smaller storage containers 80 shown in FIG. 12 are approximately half the size of the smaller storage containers 80 shown in FIG. 1. Notably, the shortest horizontal edges of the smaller storage containers 80 in FIG. 1 are approximately the same length as the longest horizontal edges of each of the smaller storage containers 80 in FIG. 12. In use, the smaller storage containers 80 in FIG. 1 can be loaded onto the trapdoor 111 with their shortest horizontal edges leading, and the smaller storage containers 80 in FIG. 12 can be loaded onto the trapdoor 111 with their longest horizontal edges leading. In this manner, both sizes of smaller storage containers 80 can be fed onto the trapdoor 111 using a conveyor of the same width. When the trapdoor 111 is opened, the multiple smaller storage containers 80 are lowered into the larger storage container 90 in a manner similar to that described above for the single smaller storage container 80.

[0069] If one of the smaller storage containers 80 is smaller than the other in a direction perpendicular to the pivot axis 121, or if the smaller storage containers 80 have different weights, it may be beneficial to use elastically deflectable door panels 112 that are each split along an axis perpendicular to the pivot axis 121 so that each door panel 112 comprises two portions 112a, 112b, as shown in FIG. 13. If more than two smaller storage containers 80 are loaded side by side, the number of portions may increase accordingly. Although the portions 112a, 112b of each door panel 112 are illustrated as separate portions in FIG. 13, they may also be joined at the mounting end of the door panel 112. Both portions of each door panel 112 are connected to the same shaft 120 so that both portions 112a, 112b pivotally rotate together but each portion 112a, 112b can deflect independently. In this example, the container stowage assembly 110 includes a displacement sensor 128 above each smaller storage container 80 to measure its vertical displacement during descent, and the controller 127 uses a closed-loop control system during the friction control regime to control the angular position of the door panel 112 based on which smaller storage container 80 is descending or accelerating the fastest. In other words, the angular position of the door panel 112 is controlled to keep the fastest descending smaller storage container 80 below a predetermined maximum velocity and / or acceleration threshold. In this way, it can be ensured that both smaller storage containers 80 descend without exceeding the maximum velocity and / or acceleration threshold. Alternatively, each door panel portion 112 a, 112 b can be rigidly fixed to an independently rotatable shaft 120 so that the angular position of each door panel portion 112 a, 112 b can be individually controlled. Alternatively, the pusher device 140 described above can be used to push down the smaller storage container 80 at the same specified speed in the manner described above in connection with FIG.

[0070] As an alternative to loading multiple smaller storage containers 80 side-by-side into a single larger storage container 90, multiple smaller storage containers 80 may be loaded into the larger storage container 90 such that they are stacked vertically within the single larger storage container 90. To do this, a first smaller storage container 80 may be loaded into the larger storage container 90 in a first stowage position in the manner already described above. The loaded larger storage container 90 may then be lowered so that the trap door 111 can be closed by rotating the door panel 112 back to a horizontal position. A second smaller storage container 80 may then be loaded into the larger storage container 90 in the same manner, but with the larger storage container 90 in a second stowage position that is lower than the first stowage position so that the door panel 112 does not hit the first smaller storage container 80 when it is pivotally rotated downward.

[0071] The above two methods for loading multiple smaller storage containers 80 into a larger storage container 90 can also be combined so that the smaller storage containers are loaded in a side-by-side vertically stacked arrangement, for example, a 2x2 arrangement with two side-by-side smaller storage containers 80 in a first layer and another two side-by-side smaller storage containers 80 in a second layer above the first layer.

[0072] 14 shows a top view of an alternative door panel 212 for use with the trapdoor 111, as well as a top view of a previous door panel 112 for comparison. In contrast to the door panels 112 in which the free end 114 of each door panel 112 was straight, the free end 214 of each door panel 212 has a castellation shape, i.e., a series of alternating protrusions 215 and recesses 216 that extend in the plane of the door panel 212. Furthermore, the castellations are arranged so that the castellations of one door panel 212 interdigitate with the castellations of the other door panel 212, i.e., the protrusions 215 of one of the door panels 212 fit into the recesses 216 of the other door panel 212, and vice versa, when the door panels 212 are in a horizontal position. As illustrated in Figure 14, this configuration effectively extends the maximum width of each door panel 212 a distance X beyond the midpoint between the two door panels 212 so that the two door panels 212 do not obstruct each other. This allows the door panels 212 to remain in contact with the smaller storage container 80 over a greater portion of the smaller storage container's descent compared to the door panels 112 of the trapdoor 111, whose maximum width is limited to half the distance between the two pivot axes 121. This is illustrated by the side cross-sectional view shown in Figure 15, in which the castellated door panel 212 shown on the left extends further into the larger storage container 90 by the distance X compared to the door panel 112 shown on the right.

[0073] The above-described embodiment of the automated container loader 100 thus uses frictional engagement to load smaller storage containers 80 into larger storage containers 90 in an automated and controlled manner, avoiding large drop impacts that could damage items (such as grocery items or fragile items) contained within the smaller storage containers 80. However, the automated container loader 100 is not limited to loading one storage container into another. In general, the automated container loader 100 may be used to drop other objects under gravity in a controlled manner that attempts to minimize damage to the objects. For example, instead of loading a smaller storage container containing an item into a larger storage container, the automated container loader 100 may be used to load the item directly into the storage container or onto another surface.

[0074] The present invention is not limited to the exact form described above, and various modifications and variations are possible without departing from the scope of the invention as defined in the appended claims. A non-exhaustive list of some illustrative modifications and variations is set forth below.

[0075] Instead of the trapdoor 111 having two door panels 112, the trapdoor may include more than two door panels. For example, the trapdoor may include three, four, five, six, or more door panels. The door panels and their respective pivot axes may be symmetrically positioned about a center point. The door panels may be triangular in shape and point inward toward the center point.

[0076] 1 and 3 show the smaller storage container 80 moving onto the trapdoor 111 in a direction parallel to the pivot axis 121 of the door panel 112, the smaller storage container 80 can also move onto the trapdoor in a direction perpendicular to the pivot axis 121. In this case, the side guides 119 can also be oriented perpendicular to the pivot axis 121. Similarly, the larger storage container 90 can move onto and off the container support 130 in a direction perpendicular to the pivot axis 121.

[0077] Instead of using an electric linear actuator 126 to drive the rotation of the door panel 112, other actuators, such as pneumatic or hydraulic actuators, may be used instead. Actuators that can only move between two extreme positions (and are not capable of stopping at positions in between) may also be used in the automated container loader 100. In this case, an open-loop control system may be used in which the door panel 112 is pivotally rotated according to a predetermined motion profile so that the smaller storage containers 80 do not exceed a predetermined maximum acceleration threshold. Such a system may be suitable for situations in which smaller storage containers 80 of a predetermined size and weight (or within a predetermined size and weight range) are loaded.

[0078] Instead of the door panels 112 being mechanically coupled to a carriage 123 that is vertically guided by a linkage arm 124 and a joint 125, a different mechanism can be used to pivotally rotate the door panels 112 in unison. For example, the rotation of the door panels 112 can be driven by a gear arrangement or a pulley arrangement. For example, a rack and pinion gear arrangement can be used, where a common rack gear drives a pinion gear on each door panel 112.

[0079] Instead of the door panels 112 being configured to rotate in unison, the door panels 112 may be independently rotatable about their respective pivot axes 121, for example, by using separately controlled rotational actuators for each door panel 112. In this case, the controller 127 may still be configured to rotate the door panels 112 in unison (by controlling the actuators in unison), or the controller 127 may adjust the angular position of one door panel 112 independently of the other door panel during lowering of the smaller storage container 80.

[0080] The control system may include multiple displacement sensors 128 configured to measure the vertical displacement of different portions of the smaller storage container 80 as it is lowered into the larger storage container 90. For example, a displacement sensor 128 may be positioned to measure the vertical displacement of each corner of the smaller storage container 80. The controller 127 may calculate and use an average of measurements from the multiple displacement sensors 128. The controller 127 may also use measurements from each displacement sensor 128 to detect when the smaller storage container 80 is tilted to one side relative to a horizontal plane. In this case, if the door panels are configured to be independently rotatable, the controller 127 may be configured to adjust the angular position of each door panel to return the smaller storage container 80 to a substantially horizontal position. Alternatively, the controller 127 may be configured to halt further pivotal movement of the door panels so that the smaller storage container 80 can be manually removed from the trapdoor.

[0081] In the release control regime C3 described above, the door panel 112 is not limited to moving to a vertical position to disengage from the smaller storage container 80. The door panel 112 can disengage before the vertical position or can rotate past the vertical position to disengage, depending on the size of the smaller storage container 80. Furthermore, the release control regime can be omitted entirely from the control system because, at the end of the friction regime, the door panel 112 is still in an angular position that allows the smaller storage container 80 to slide past it under gravity. Thus, provided the larger storage container 80 is lowered away from the trapdoor 111 at a sufficiently slow rate, the smaller storage container 80 will descend with the larger storage container 90 until the smaller storage container 80 vertically clears the door panel 112. However, the release control regime C3 can be advantageous because it reduces wear on the door panel 112 (caused by sliding contact) over time.

[0082] The controller 127 is not limited to controlling the door panel 112 according to the three control regimes C1-C3 described above. Any number of control regimes may be used to provide the effect of reducing the impact force between the smaller storage container 80 and the larger storage container 90 when the smaller storage container 80 is loaded into the larger storage container 90. As already described above, the release control regime C3 may be omitted. In another example, the friction control regime in which the door panel contacts the sidewall 82 of the smaller storage container 80 may be divided into two control regimes: an open-loop control regime in which the door panel is moved to a predetermined angular position using a predetermined motion profile, as already described above, followed by a closed-loop control regime in which the angular position of the door panel 112 is adjusted based on feedback from the displacement sensor 128. Dividing the friction control regime C2 in this manner may help reduce cycle time because the descent of the smaller storage container 80 does not necessarily need to be finely controlled at the start of the friction control regime C2.

[0083] The door panel 112 does not necessarily need to remain in contact with the smaller storage container 80 throughout the entire descent of the smaller storage container 80 into the larger storage container 90. For example, if the door panel 112 is not wide enough, the friction control regime may end (i.e., the door panel may disengage from the smaller storage container 80) before the smaller storage container 80 reaches the base of the larger storage container 90. This may be acceptable, provided that when the smaller storage container 80 reaches the base of the larger storage container 90, the free fall distance is short enough so that any items inside the smaller storage container 80 are not damaged.

[0084] Instead of the container support 130 including a lifting mechanism 134 for vertically moving the larger storage container 90 relative to the trapdoor 111 between the stowed and released positions described above, the trapdoor 111 may include a lifting mechanism for vertically moving the trapdoor 111 relative to the larger storage container 90 to achieve the same effect, i.e., to position the trapdoor 111 and the larger storage container 90 vertically relative to each other in a stowed configuration in which at least a portion of each door panel 112 enters the larger storage container when the door panels are pivotally rotated toward their final positions, and in a released configuration in which the smaller storage container 80 is vertically separated from the door panel 112 when the door panels are in their final positions.

[0085] The container stowage assembly 110 does not necessarily have to be used to stow the smaller storage containers 80 in a downward direction under gravity. Generally, the door panels 112 of the trap door 111 can be pivotally rotated to an angular position that frictionally engages / resists movement of the smaller storage containers 80 between the door panels 112 to control the speed of the smaller storage containers 80 as they pass between the door panels 112. The orientation of the trap door 111 can be changed to stow the smaller storage containers 80 into the larger storage container 90 in any particular direction, for example, horizontally or upward. Such an example would need to be used with a pushing device, such as the pushing device 140 described above, to push the smaller storage containers 80 through the trap door 111 in the desired direction.

[0086] The automated container loader 100 can be part of a storage and retrieval system in which stacks of larger storage containers 90 are arranged in a 3D grid storage structure. An illustrative grid storage structure 1 is shown in FIG. 16 . The grid storage structure 1 includes upright members 3 supporting a first set 5 and a second set 7 of horizontal members. The first set 5 and second set 7 of horizontal members extend perpendicular to one another to form a grid pattern defining a plurality of grid cells 14. The larger storage containers 90 are arranged in stacks 11 directly below the grid cells 14, with one stack of larger storage containers per grid cell. The larger storage containers 90 are accessed from above by a load handling device 31 operable on a track structure 13 located at the top of the grid storage structure. The track structure 13 can include tracks mounted on top of the horizontal members 5, 7, or the tracks can be provided by the horizontal members 5, 7 themselves (e.g., formed in or on the surface of the horizontal members 5, 7). The automated container loader 100 may be located in an input area of ​​the storage and retrieval system where smaller storage containers 80 containing items (e.g., grocery items) are received and loaded into empty larger storage containers 90 using the automated container loader 100. The loaded larger storage containers may then be transported to the grid storage structure 1 for storage in stacks 11 within the grid storage structure 1.

Claims

1. 1. An automated container loader for loading smaller storage containers into larger storage containers, comprising: a container support for receiving a larger storage container; a container stowage assembly configured to receive a smaller storage container above the larger storage container and release the smaller storage container to allow the smaller storage container to descend under gravity into the larger storage container; wherein the container stowage assembly comprises a plurality of engagement surfaces configured to engage the smaller storage container during at least a portion of a descent of the smaller storage container to control a rate of descent of the smaller storage container under gravity.

2. The container stowage assembly includes: a trapdoor comprising at least two door panels, each door panel defining one of said plurality of engagement surfaces, each door panel pivotally mounted for rotation about a respective horizontal pivot axis, wherein said door panels are pivotally rotatable downward from a substantially horizontal initial position for receiving said smaller storage container above said larger storage container to a final position for allowing said smaller storage container to descend under gravity between said horizontal pivot axes into said larger storage container; a control system including a controller configured to control pivotal rotation of the door panel between the initial position and the final position such that the door panel frictionally engages the smaller storage container during at least a portion of the descent of the smaller storage container under gravity; and 10. The automated container loader of claim 1, comprising:

3. 3. The automated container loader of claim 2, wherein the controller is configured to control pivotal rotation of the door panels such that the door panels frictionally engage side walls of the respective smaller storage containers during at least a portion of a descent of the smaller storage containers.

4. 4. The automatic container loader according to claim 2, wherein the door panel is stoppable at at least one intermediate angular position between the initial position and the final position.

5. 5. The automated container loader of claim 2, wherein the control system further comprises at least one displacement sensor configured to measure vertical displacement of the smaller storage container during the portion of its descent, and wherein the controller is configured to control the intermediate angular position of the door panel based on displacement measurements from the at least one displacement sensor.

6. 6. The automated container loader of claim 5, wherein the controller is configured to determine a descent speed and / or acceleration of the smaller storage container based on measurements from at least one of the displacement sensors, and wherein the controller is configured to control the intermediate angular position of the door panel to keep the descent speed and / or acceleration of the smaller storage container below a maximum speed and / or acceleration threshold.

7. 7. The automated container loader of claim 6, wherein the controller is configured to pivotally rotate the door panel upward when a descent speed and / or acceleration of the smaller storage container exceeds the maximum speed and / or acceleration threshold.

8. 8. The automated container loader of claim 7, wherein the controller is further configured to pivotally rotate the door panel downward when a descent speed and / or acceleration of the smaller storage container falls below a minimum speed and / or acceleration threshold.

9. 9. The automated container loader of claim 2, wherein the control system comprises a plurality of displacement sensors configured to measure vertical displacement of different portions of the smaller storage container during descent of the smaller storage container, the controller configured to determine an orientation of the smaller storage container relative to a horizontal plane based on measurements from the plurality of displacement sensors, and the controller configured to interrupt pivotal rotation of the door panel if the controller determines that the smaller storage container is tilted away from the horizontal plane by a predetermined degree.

10. 9. The automated container loader of claim 2, wherein the control system comprises a plurality of displacement sensors configured to measure vertical displacement of different portions of the smaller storage container during descent of the smaller storage container, the controller configured to determine an orientation of the smaller storage container relative to a horizontal plane based on measurements from the plurality of displacement sensors, and the controller configured to control the intermediate angular position of each door panel to maintain an orientation of the smaller storage container substantially horizontal during descent of the smaller storage container.

11. The automated container loader of any one of claims 2 to 4, wherein the controller is configured to pivotally rotate the door panel between the initial position and the final position according to a predetermined motion profile.

12. 12. The automated container loader of claim 2, wherein the controller is configured to control the pivotal rotation of the door panel to stop the descent of the smaller storage container at an intermediate lowered position above a final lowered position, and the container loading assembly further comprises a pushing device configured to push the smaller storage container downwardly from the intermediate lowered position to the final lowered position at a predetermined speed.

13. An automatic container loader according to any one of claims 2 to 12, wherein the door panel is resiliently flexible.

14. An automated container loader according to any one of claims 2 to 13, wherein each door panel is divided along a direction perpendicular to the horizontal pivot axis to define a first door panel portion and a second door panel portion.

15. 15. An automatic container loader as described in any one of claims 2 to 14, wherein each door panel has a mounting end to which the door panel is pivotally mounted and a free end opposite the mounting end, each free end having a castellation shape, and the door panels are arranged such that the castellations at the free ends interlock with each other when the door panels are in the horizontal initial position.

16. An automated container loader according to any one of claims 2 to 15, wherein the door panels are configured to pivotally rotate in unison.

17. 16. An automated container loader according to any one of claims 2 to 15, wherein the door panels are pivotably rotatable independently of one another, and the controller is configured to control the intermediate angular positions of the door panels independently of one another.

18. 18. The automated container loader of claim 2, wherein the container stowage assembly further comprises guide members above the trapdoor, the guide members configured to engage with side walls of each of the smaller storage containers to help guide the smaller storage containers into a symmetrical position on the door panel and / or maintain a vertical orientation of the smaller storage containers during at least a portion of their descent into the larger storage container.

19. 19. An automated container loader as described in any one of claims 2 to 18, wherein the container support and the trap door are vertically movable relative to one another to allow the larger storage container and the door panel to be moved into relative positions where pivotal rotation of the door panel from the initial position to the final position rotates the door panel into the larger storage container.

20. 1. A method for automated loading of a smaller storage container into a larger storage container, the method comprising: receiving a smaller storage container on a trapdoor above a larger storage container, said trapdoor having at least two pivotally mounted door panels in a horizontal initial position for receiving said smaller storage container; pivotally rotating the door panel downward to allow the smaller storage container to descend under gravity into the larger storage container between the door panels; controlling pivotal rotation of the door panel during descent of the smaller storage container such that the door panel frictionally engages the smaller storage container during at least a portion of the descent; A method comprising:

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