Load handling apparatus

Abstract

A load handling apparatus is provided for lifting and moving containers stacked in stacks in a storage system.SOLUTION: A load handling apparatus (100) includes a body (102), a wheel assembly arranged to support the body, a container lifting mechanism configured to lift a container (10) to or from the body, and a wheel positioning mechanism comprising wheel engagement means for selectively engaging a first set of wheels (116) of the wheel assembly with a first set of rails or tracks of a storage system, or a second set of wheels (118) of the wheel assembly with a second set of rails or tracks of the storage system. The wheel engagement means may comprise at least one non-vertical linear actuator and / or at least one eccentric rotation-based wheel engagement means.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a load handling device, and in particular to a robotic load handling device suitable for moving one or more loads between different locations. [Background technology]

[0002] Robotic load handling devices (“robots” or “bots”) are used to move loads from one location to another. They may be used, for example, to move totes, boxes, or other containers within and / or out of a storage system, such as the storage grid 1 illustrated in FIG. 1 . The illustrated storage grid 1 includes a frame structure 14 having a plurality of upright members 16 supporting horizontal members 18, 20. A first set of parallel horizontal members 18 is disposed perpendicular to a second set of parallel horizontal members 20 to form a plurality of horizontal grid structures supported by the upright members 16. The members 16, 18, 20 are typically fabricated from metal. Because the containers 10 are stacked between the members 16, 18, 20 of the frame structure 14, the frame structure 14 guards against horizontal movement of the stack 12 of containers 10 and guides or limits vertical movement of the containers 10.

[0003] The illustrated storage grid 1 also includes a plurality of rails or tracks 22 arranged in a grid pattern above the stacks 12 of containers 10, the grid pattern including a plurality of grid spaces, with each stack 12 of containers 10 positioned within the footprint of only a single grid space. The bots are configured to move laterally on the rails or tracks 22 above the stacks and move totes relative to the grid using respective container lifting mechanisms that enable lifting at least one tote into the container receiving space of the bot.

[0004] The claimed load handling apparatus, method and computer program are intended to provide improvements over known load handling apparatus. Summary of the Invention

[0005] According to one embodiment, there is provided a load handling apparatus as set forth in claim 1. According to a further embodiment, there is provided a method as set forth in claim 10. According to another embodiment, there is provided a computer program as set forth in claim 12. According to a different embodiment, there is provided a load handling apparatus as set forth in claim 14. According to another embodiment, there is provided a method as set forth in claim 21. According to yet another embodiment, there is provided a computer program as set forth in claim 23.According to yet another embodiment, there is provided a load handling apparatus for lifting and moving containers stacked in a stack in a storage system, the storage system including a plurality of rails or tracks arranged in a grid pattern above the stack of containers, the load handling apparatus configured to move on the rails or tracks above the stack, the load handling apparatus comprising a body having an upper portion and a lower portion, the upper portion configured to accommodate one or more operating components and the lower portion disposed below the upper portion, the lower portion comprising a container receiving space for fitting at least one container, a wheel assembly arranged to support the body, the wheel assembly comprising: a first set of wheels for engaging the first set of rails or tracks to guide movement of the apparatus in a first direction; and a second set of wheels for engaging the second set of rails or tracks to guide movement of the apparatus in a second direction, and a container lifting mechanism, the container lifting mechanism comprising: container engaging means configured to engage a container; and lifting means configured to raise and lower the container engaging means relative to the container accommodating space; and a wheel positioning mechanism, the wheel positioning mechanism comprising wheel engaging means for selectively engaging a first set of wheels with the first set of rails or tracks or a second set of wheels with the second set of rails or tracks, the wheel engaging means being configured to raise or lower the first set of wheels or the second set of wheels relative to the body, thereby enabling the load handling apparatus to selectively move in either the first direction or the second direction across the tracks of the storage system, wherein the wheel engaging means comprises fluid-based wheel engaging means.

[0006] Such a load handling apparatus, method or computer program may provide one or more advantages with respect to the usability of the load handling apparatus, the mechanical advantage of the wheel positioning mechanism, the volume of space available within the load handling apparatus, and other factors, as will be explained in more detail in the detailed description below. Optional features are set out in the dependent claims. The tote handling system will now be described in detail with reference to an example. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 illustrates a schematic representation of a storage grid. [Figure 2] FIG. 2 illustrates a schematic diagram of a load handling device. [Figure 3] FIG. 3 illustrates a schematic diagram of a load handling device. [Figure 4] FIG. 4 illustrates a schematic diagram of a load handling device. [Figure 5] FIG. 5 illustrates schematically a wheel positioning mechanism for a load handling device. [Figure 6] FIG. 6 illustrates schematically a wheel positioning mechanism for a load handling device. [Figure 7] FIG. 7 illustrates schematically a wheel positioning mechanism for a load handling device. [Figure 8] FIG. 8 illustrates schematically a wheel positioning mechanism for a load handling device. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present embodiment represents a preferred example of how aspects of a load handling apparatus may be implemented, but is not necessarily the only example of how such aspects may be implemented.

[0009] FIG. 1 illustrates a storage system comprising a storage grid 1. The storage grid 1 includes a plurality of rails or tracks 22 arranged in a grid pattern on a stack 12 of containers 10. Each container 10 can accommodate one or more items, which are stored in the storage grid 1 until the items are needed, for example, until an order is placed for one of the items in the container 10. Alternatively, one or more of the containers 10 in the storage grid 1 may be empty and ready to accommodate one or more items.

[0010] The grid pattern of the storage grid 1 includes multiple grid spaces, with each stack 12 of containers 10 positioned within the footprint of a single grid space. Multiple load handling devices 100 ("robots" or "bots"), such as the load handling device 100 illustrated in FIG. 2, are configured to move laterally on rails or tracks 22 above the stacks 12 to access the grid space above any given stack 12 of containers 10 and retrieve one or more containers 10 from the stack 12. In the illustrated example, each bot 100 occupies only a single grid space at the top of the storage grid 1. In other examples, a bot can occupy multiple grid spaces.

[0011] As shown in FIG. 2, the bot 100 comprises a body 102 having an upper portion 112 and a lower portion 114 .

[0012] The upper portion 112 is configured to at least partially house one or more operating components. Possible examples of operating components that may be housed in the upper portion 112 include one or more power components, such as a battery 191 configured to power one or more other components of the bot 100, one or more control components configured to control one or more other components of the bot 100, one or more drive components configured to drive the bot 100 along the track 22 of the storage grid 1, and one or more container lifting mechanisms configured to lift a container 10 from the stack 12. In the illustrated example, only the battery 191 is shown for simplicity.

[0013] The lower portion 114 is disposed below the upper portion 112. The lower portion 114 includes a container-receiving space 120 or cavity 120 that fits a container 10. The container lifting mechanism described above can be configured to lift one or more containers 10 from a stack 12 of containers 10 in the storage grid 1 into the container-receiving space 120 and to lower one or more containers 10 from the container-receiving space 120, for example, onto a different stack 12 of containers 10, onto the same stack 12 of containers 10, or to a different location, such as a picking station or exit point of the storage grid 1 (i.e., a point at which a container 10 can exit the storage grid 1) where items can be transferred to or removed from the one or more containers 10. The container lifting mechanism may include, for example, container engaging means configured to grip or otherwise engage and hold one or more containers, and one or more motors or other lifting means configured to raise and lower the container engaging means, and any containers engaged by the container engaging means, into and out of the container-receiving space 120. The container engaging means may be referred to as a container gripping means or gripper. The container lifting mechanism may be at least partially housed within the lower portion 114 of the body 102 when the container lifting mechanism is in the retracted position.

[0014] A wheel assembly configured to enable the bot 100 to engage rails or tracks 22 of the storage grid 1 illustrated in FIG. 1 is connected to the body 102 of the bot 100 at a lower portion 114 of the body 102. The rails or tracks 22 of the storage grid 1 include a first set of rails or tracks 22a extending in a first direction (along or substantially parallel to the x-axis illustrated in FIG. 1) and a second set of rails or tracks 22b extending in a second direction (along or substantially parallel to the y-axis illustrated in FIG. 1). In the illustrated example, the second direction is substantially perpendicular to the first direction (i.e., rails 22a are at approximately 90° with respect to rails 22b), although in other examples the angle between the two sets of rails may be different. The wheel assembly includes a first set of wheels 116 configured to be engageable with tracks 22a in a first set of rails or tracks 22a to guide movement of the bot 100 in a first direction, and a second set of wheels 118 configured to be engageable with tracks 22b in a second set of rails or tracks 22b to guide movement of the bot 100 in a second direction.

[0015] The illustrated first set of wheels 116 includes a total of four wheels, i.e., two wheels positioned on a first side of the bot 100 (e.g., the longer side illustrated toward the right in FIG. 2 ) and two wheels positioned on a third side of the bot 100 opposite the first side (the third side of the bot not properly visible in FIG. 2 ). Similarly, the illustrated second set of wheels 118 includes a total of four wheels, i.e., two wheels positioned on a second side of the bot 100 (e.g., the shorter side illustrated toward the left in FIG. 2 ) and two wheels positioned on a fourth side of the bot 100 opposite the second side (the fourth side of the bot not properly visible in FIG. 2 ). In other embodiments, a different number of wheels may be provided in the first set and / or second set. For example, in some embodiments, it may be advantageous to have three or four wheels on one or more sides of the bot 100.

[0016] The wheel positioning mechanism is provided on the lower portion 114 of the body 102. The wheel positioning mechanism includes wheel engagement means for selectively engaging the first set of wheels 116 with the tracks 22a of the first set of rails or tracks 22a to allow the bot 100 to move in a first direction or the second set of wheels 118 with the tracks 22b of the second set of rails or tracks 22b to allow the bot to move in a second direction. The wheel engagement means, in the embodiment illustrated in FIG. 2, includes movement means in the form of a linear actuator configured to apply an upward or downward force to each pair of wheels.

[0017] In the example illustrated in Figure 2, the first linear actuator 188 is pivotally mounted to the longer visible side (referred to as the first side) of the bot 100 and is indirectly connected to a pair of wheels 116 on that first side of the bot 100. The two wheels labeled 116 in Figure 2 constitute two of the four wheels in the first set of wheels 116.

[0018] The first linear actuator 188 raises or lowers the illustrated pair of wheels 116 relative to the body 102 of the bot 100, lifting the pair of wheels 116 away from or lowering the pair of wheels 116 toward the tracks 22a of the first set of tracks 22a. A corresponding third linear actuator (not fully visible in FIG. 2 ) is pivotally mounted on the opposite long side (referred to as the third side) of the bot 100 and indirectly connected to the pair of wheels on that third side of the bot 100. The two wheels on the third side of the bot 100 constitute the other two of the four wheels in the first set of wheels 116. The third linear actuator raises or lowers the corresponding pair of wheels relative to the body 102 of the bot 100, lifting the pair of wheels away from or lowering the pair of wheels toward the tracks 22a of the first set of tracks 22a.

[0019] Similarly, a second linear actuator 189 is pivotally mounted to the shorter, visible side (referred to as the second side) of the bot 100 in FIG. 2 and indirectly connected to a pair of wheels 118 on that second side of the bot 100. The two wheels 118 on the second side of the bot 100 constitute two of the four wheels in the second set of wheels 118. The second linear actuator 189 raises or lowers the illustrated pair of wheels 118 relative to the body 102 of the bot 100, lifting the pair of wheels 118 away from or lowering them toward the tracks 22b of the second set of tracks 22b. A corresponding fourth linear actuator (not fully visible in FIG. 2) is pivotally mounted to the opposite, shorter side (referred to as the fourth side) of the bot 100 and indirectly connected to a pair of wheels on that fourth side of the bot 100. The two wheels on the fourth side of the bot 100 make up the other two of the four wheels in the second set of wheels 118. A fourth linear actuator raises or lowers a corresponding pair of wheels relative to the body 102 of the bot 100, lifting the pair of wheels away from or lowering them toward the tracks 22b of the second set of tracks 22b.

[0020] The four linear actuators may be independently controllable, but generally, the first linear actuator 188 and the third linear actuator are controlled to raise or lower their respective wheels 116 substantially simultaneously with one another, and the second linear actuator 189 and the fourth linear actuator are controlled to raise or lower their respective wheels 118 substantially simultaneously with one another. This allows either all four wheels of the first set of wheels 116 to contact the tracks of the first set of tracks 22a at once, or all four wheels of the second set of wheels 118 to contact the tracks of the second set of tracks 22b at once, allowing the bot 100 to selectively move across the grid in either a first (x) direction or a second (y) direction.

[0021] Advantageously, this configuration of four linear actuators configured to raise and / or lower each pair of wheels 116, 118 relative to the body 102 of the bot 100 allows for minimal shifting of the center of gravity of the bot 100 when the bot 100 changes direction of movement (i.e., from a state configured to move along the first set of tracks 22a in a first direction to a state configured to move along the second set of tracks 22b in a second direction, or vice versa). For example, when the bot 100 is moving in a first direction along the first set of tracks 22a, the first set of wheels 116 (indirectly connected to the first and third linear actuators) is maintained in a lowered configuration, where the first set of wheels 116 contacts the tracks 22a of the first set of tracks 22a, and the second set of wheels 118 (indirectly connected to the second and fourth linear actuators) is maintained in an upper configuration, where the second set of wheels 118 does not contact the tracks 22b of the second set of tracks 22b.

[0022] When the bot 100 reaches a contact point on the grid 1 and needs to change its direction of movement, the second and fourth linear actuators can lower the second set of wheels 118 so that the second set of wheels 118 contacts the tracks 22b of the second set of tracks 22b. This involves little or no movement of the bot 100's center of gravity, because the majority of the bot 100's mass (including any containers 10 and container contents currently within the vehicle's container storage space 120) remains stationary in the z-direction, supported by the first set of wheels 116. When the second set of wheels 118 contacts the tracks 22b, the first and third linear actuators can raise the first set of wheels 116 so that the first set of wheels 116 no longer contacts the tracks 22a of the first set of tracks 22a. This also involves little or no movement of the bot's center of gravity, as the majority of the bot's mass (including any containers 10 and container contents) remains stationary and is supported by the second set of wheels 118. The bot 100 can then move in a second direction along the tracks 22b of the second set of tracks 22b. If the bot 100 needs to change direction again, the second set of wheels 118 may remain in contact with the tracks 22b while the first and third actuators lower the first set of wheels 116 into contact with the tracks 22a. When the first set of wheels 116 is in contact with the tracks 22a, the second and fourth actuators lift the second set of wheels 118 off the tracks 22b, so that the weight of the bot 100 is supported only by the first set of wheels 116 and the bot 100 can move in a first direction along the tracks 22a. Throughout the process of raising and lowering the sets of wheels 116, 118 using the first, second, third, and fourth actuators, movement of the center of gravity of the bot 100 is minimized.

[0023] Minimizing the movement of the center of gravity of the bot 100 can have numerous advantages, including minimizing wear on the tracks 22a, 22b and other components of the lattice 1 since the change in force on the lattice 1 due to an increase in the bot's mass is minimized; minimizing vibration and corresponding noise and collapse of the lattice 1 when the bot 100 changes direction; minimizing wear on the components of the bot 100 since the forces applied to the components are minimized when the bot 100 changes direction; minimizing the force requirements for the linear actuators for arrangements in which only one set of wheels 116 or 118 is configured to raise or lower relative to the body of the bot 100 (in such embodiments, the entire weight of the bot 100 needs to be lifted when one set of wheels is lowered, whereas in the configurations herein, only the weight of the wheels and the components to which they are mounted need to be lifted), which allows for the use of lighter, faster, and / or less costly wheel engagement means (in the illustrated example, a linear actuator) than in alternative arrangements.

[0024] Minimizing shifts in the vehicle's center of gravity can also result in a substantially constant height of the bot 100 during use. This may advantageously mean that any connectors or other components attached to the bot 100 that need to connect or interact with corresponding connectors or other components mounted externally to the bot 100, such as above or at the edge of the storage grid 1, can more reliably connect or interact with the corresponding connectors / components without adjusting the bot 100 and / or the external connectors or other components. This allows routine operations, such as charging the bot 100 at a charging station positioned around the periphery of the storage grid 1, to be performed more efficiently and with fewer external inputs than in bot embodiments in which the bot's center of gravity shifts significantly up and down, allowing the bot to change direction (in which case the charging equipment and / or the bot would need to be raised or lowered so that the bot could engage the charging equipment).

[0025] In some examples, one set of wheels 116, 118 may be lowered substantially simultaneously as the other set is raised, which may result in a greater shift in the center of gravity of the bot 100, but may advantageously reduce the time required to change the direction of movement of the bot 100.

[0026] Components of two of the four linear actuators and components connecting these two linear actuators to their respective pairs of wheels 116, 118 are labeled in FIG. 3 . The same reference numbers are used to indicate common features of the two illustrated linear actuators and connecting components. In the illustrated example, the two labeled linear actuators are identical to each other and to linear actuators, not fully illustrated, on the other two sides of the bot 100. Therefore, the following description applies equally to all four linear actuators. In other examples, the linear actuators may be different from each other. In some examples, one or more of the four linear actuators on the four sides of the bot may be replaced by a different type of movement means and / or wheel engagement means, such as a rotary motor, a pneumatic or hydraulic piston, or an alternative configuration. In other embodiments, only two engagement and movement means (e.g., linear actuators) may be provided, for example, on the first and third or second and fourth sides of the bot. In such cases, the weight of the bot may be raised or lowered when one set of wheels is removed from contact with the respective tracks and the other set of wheels is brought into contact with the respective tracks.

[0027] Each linear actuator includes a housing 318 pivotally mounted to the body 102 of the robot 100 at a respective first pivot point P1 (see FIG. 4). The linear actuator's telescopic member 316 is movably connected to the housing 318. The extension / retraction member 316 can be further moved into or out of the housing 318, for example, by a corresponding motor or other movement means that may be positioned within the housing 318. The extension / retraction member 316 is pivotally connected to a first end of a linkage 312 via a pivot connector 314. The linkages 312 are pivotally mounted to the body 102 of the robot 100 at a respective second pivot point P2 (see FIG. 4). The roller 310 is rotatably connected to a second end of the linkage 312. The frame 320 is attached to a panel 324 to which the two wheels 116 or 118 are rotatably mounted. The frame 320 includes an opening or recess 322 within which the roller 310 can roll. The two pivot points P1 and P2 and the frame 320 limit the range of movement that the housing 318, the extension / retraction member 316, the pivot connector 314, the linkage 312, and the roller 310 can undergo.

[0028] The movement of one linear actuator and its associated components from a fully retracted (wheels down) configuration to a fully extended (wheels up) configuration will now be described with reference to the illustrated example. When the linear actuator is in the fully retracted configuration, the extension / retraction member 316 is in its most retracted position within the housing 318 (see the extension / retraction member 316 of the linear actuator on the long side of the robot toward the left in FIG. 3 ; a portion of the extension / retraction member 316 may still be outside the housing 318 in the fully retracted configuration). Thus, the pivot connector 314 is closest to the housing 318. The linkage 312 pivots about the second pivot P2 so that the first end of the linkage 312 is to the right of the second pivot P2 (as viewed in the figure). The second end of the linkage is to the left of the second pivot P2. Thus, the roller 310 is also to the left of the second pivot P2 and exerts a downward pressure on the underside of the opening 322 in the frame 320. This downward pushing force is applied by the frame 320 to the panel 324 on which the wheels are mounted. Thus, the wheels are held in their lowered configuration when the linear actuator is in its fully retracted configuration. The bot 100 may include one or more brakes, latches, or stops to limit movement of the extension / retraction member 316 away from the fully retracted or fully extended position. For example, brakes and / or end stops may be provided within the housing 318 to help limit movement of the extension / retraction member 316 beyond its intended fully retracted position and / or toward the extended configuration when the extension / retraction member 316 is in the retracted configuration. This can help prevent damage to the housing 318, the extension / retraction member 316, components connected to the linear actuator, and / or to other components of the bot 100 or the lattice 1. This can help reduce the risk of the support wheels of the bot 100 unexpectedly moving from a lowered configuration to an elevated configuration, thus reducing the risk of the bot 100 suddenly collapsing onto the lattice 1.

[0029] To move the wheel from the lowered configuration to the raised configuration, the linear actuator drives the extension / retraction member 316 further out of the housing 318 toward a position where the extension / retraction member 316 is on the shorter visible side of the wheel in FIG. 3 (shown toward the right in the figure). The movement of the pivot connector 314 is limited by its connection to the linkage 312 and the restriction of the linkage 312 to movement about the second pivot P2. Thus, the pivot connector 314 moves through an arc about the second pivot P2, ending in a position to the left of and lower than its initial position. To accommodate this arc of the pivoting connector 314 (to which the extension / retraction member 316 is connected or is part of the extension / retraction member 316), the housing 318 pivots about a first pivot P1, first clockwise as the pivoting connector 314 moves on the upward curve of the arc, and then counterclockwise as the pivoting connector 314 moves on the downward curve of the arc. The first end of the linkage 312 (to which the pivoting connector 314 is attached) moves through a corresponding arc, limited by pivot point P2. The second end of the linkage 312 moves correspondingly about pivot point P2, terminating in a position to the right of and higher than its initial position. The roller 310 moves correspondingly, terminating in a position to the right of and higher than its initial position. This movement of roller 310 to the right and upward causes roller 310 to apply a lifting force to the top surface of opening 322, which raises frame 320 relative to body 102 of bot 100. Frame 320, connected to the panel on which wheels 116, 118 are mounted, raises the panel and wheels 116, 118 relative to body 102 of bot 100. This allows wheels 116, 118 corresponding to a particular linear actuator to lift from their respective tracks 22a, 22b. When wheels 116, 118 are lifted from their respective tracks 22a, 22b, the other wheels 118, 116 may remain in contact with their respective tracks 22b, 22a, allowing bot 100 to move in a different direction than before.The linear actuators can extend the extension / retraction members 316 from the housing 318 until the corresponding wheels are lifted a predetermined distance relative to the body 102 of the bot 100, until a predetermined clearance is achieved between the corresponding wheels 116, 118 and the corresponding tracks 22a, 22b, or until another criterion or threshold is met. The minimum height of the wheels 116, 118 above the respective tracks 22a, 22b may be determined depending on, for example, the expected deformation of the height of the bot 100 as it moves along the tracks 22a, 22b, e.g., due to flexing of the wheel assemblies as the bot 100 moves and / or due to imperfections in the tracks 22a, 22b, or due to other factors.

[0030] The angle of the linkage 312 shown when the linear actuator is in a fully retracted position is exaggerated for illustrative purposes. The angle of the linkage 312 clockwise past vertical (as viewed from outside the robot, as shown) when the linear actuator is in a fully retracted position is very small or zero. For example, the angle of the linkage 312 clockwise past vertical may be between 0° and 5°, or more preferably between 0° and 1°. An angle greater than zero may be advantageous because it allows for an "over-center" locking function to be provided for the linkage 312 and connected components. In particular, allowing the roller 310 and linkage 312 to move past vertical may mean that the roller 310 and linkage 312 must be moved beyond an unstable "equilibrium point" from which they move independently (thus allowing the corresponding wheel to move unexpectedly up or down) before they can be moved to a stable over-center position (e.g., by the linear actuator's drive means). This can help, for example, to minimize the risk of the wheels moving unexpectedly from the lowered position, which can help to prevent the body 102 of the bot 100 from collapsing on the grid 1. It can also help to minimize the force required by the linear actuators to hold the wheels in the lowered configuration.

[0031] In an alternative example, it may be advantageous for the angle of linkage 312 to be zero with respect to the vertical when the linear actuator and associated components are in the "wheels down" configuration, which may allow for a faster and / or lower energy transition between the "wheels down" and "wheels up" configurations because the "wheels down" configuration may correspond to an arrangement with an unstable "equilibrium point" as described above, and it is easier to move each component away from it than to move the component away from a stable "over-center" position.

[0032] The process for moving the wheels from the raised position (illustrated toward the right side of FIG. 3 ) to the lowered position (illustrated toward the left side of FIG. 3 ) is substantially similar, but reversed. The linear actuator retracts the extension / retraction member 316 into the housing 318. The pivot connector 314 moves in the opposite direction along the aforementioned arc. The linkage 312 moves correspondingly about the pivot point P2, moving the roller 310 down and to the left. The roller 310 contacts the underside of the opening 322 in the frame 320 and exerts a downward force on the frame 320, thereby lowering the panel 324 and the wheels mounted thereon relative to the body 102 of the robot 100. This allows the wheels to contact the tracks of the storage grid 1.

[0033] Thus, having four such linear actuators provides a means of facilitating the transition of the bot between an "x" configuration (i.e., a configuration in which the bot can move along or parallel to the x-axis illustrated in FIG. 1) and a "y" configuration (i.e., a configuration in which the bot can move along or parallel to the y-axis illustrated in FIG. 1) by allowing different pairs of wheels to engage with corresponding tracks as needed.

[0034] In the illustrated embodiment, each linear actuator is pivotally mounted toward the right end of one side of the bot, but in other embodiments, the illustrated linear actuators and connecting components may be mounted elsewhere. For example, they may be mounted in the opposite direction from the illustrated linear actuators and components, i.e., mirrored about the centerline of each side of the bot, so that the linear actuators are instead pivotally mounted or otherwise positioned toward the left side.

[0035] As described above, the raising of one set of wheels 116, 118 may occur immediately after or during the lowering of the other set of wheels 118, 116, allowing the bot 100 to move in different directions along corresponding tracks 22a, 22b.

[0036] Advantageously, the illustrated configuration, including rollers 310 that can roll between contact with the underside of openings 322 in frame 320 and contact with the upper side of openings 322, provides a smooth application of force for raising and lowering the wheels. This can help minimize the change in force experienced by wheels 116, 118 and / or tracks 22a, 22b of storage grid 1 when wheels 116, 118 are brought into contact with tracks 22a, 22b. This configuration can advantageously extend the period of time that the weight of bot 1 on grid 1 is applied to the wheels, minimizing impact to grid 1 and / or bot 100. This can help reduce noise and vibration generated by changing from one set of wheels 116, 118 to another set of wheels 118, 116, as well as minimize damage to components of bot 100 and grid 1.

[0037] In the illustrated example, the opening 322 in the frame 320 is substantially rectangular in outline. In other examples, the opening 322 may have a different shape. For example, the opening 322 may be shaped to achieve a particular lifting trajectory or lifting speed of the frame 320, panel 324, and corresponding wheels. For example, it may be desirable for a small angle of rotation of the linkage 312 to correspond to a greater degree of lifting of the frame 320 and connected components as the linkage 312 is initially moved away from vertical, with a slower rate of lifting as the linkage 312 is moved further away from vertical. In other examples, the opposite may be preferred, i.e., when the linkage 312 is initially moved away from vertical, a small angle of rotation of the linkage 312 corresponds to a slight lifting of the frame 320 and connected components, with an increased rate of lifting as the linkage 312 is moved further away from vertical. The openings may be shaped to provide one or more "over-center" positions, as described above, where the linkage 312 and rollers 310 are less likely to move apart unintentionally, i.e., requiring a positive force to be applied by the drive means of the linear actuator to move the rollers 310 apart, rather than an "equilibrium point" where the rollers 310 can rotate apart unless restrained.

[0038] As discussed above, one or more end stops, brakes, or latches can be provided to help limit movement of the extension / retraction member 316 and / or other components beyond or away from a certain position. For example, in embodiments in which the linkage 312 is intended to not exceed 0° relative to vertical (or only slightly beyond 0° relative to vertical) in the “wheels down” configuration, one or more end stops can be provided to limit movement of the linkage 312 to or slightly beyond the 0° angle. The end stops can be provided in any of a variety of locations. For example, end stops can be provided on the frame 320 to stop movement of the roller 310 past a position corresponding to a substantially vertical orientation of the linkage 312 (i.e., a 0° angle). In some embodiments, the upright end section of the frame 320 may define an end stop, i.e., the frame 320 and / or other components connected to the linkage 312 may be sized and positioned such that the roller 310 reaches the upright end section of the frame 320 and thus cannot rotate past a position corresponding to a substantially vertical orientation of the linkage 312. Alternatively or additionally, an end stop may be provided on or within the housing 318 of the linear actuator to retract the extension / retraction member 316 sufficiently far into the housing 318 to prevent the linkage 312 from approaching beyond a substantially vertical orientation. The extension / retraction member 316 may have a feature sized and positioned to engage a corresponding feature or surface of the housing 318 to limit retraction of the extension / retraction member 316 into the housing 318. Alternatively or additionally, an end stop in the form of a rotation stop may be provided, for example, on a component of the bot 100 to which the linear actuator is mounted, to stop the linkage 312 from rotating beyond a substantially vertical orientation. The rotation stop may be located adjacent to the linkage 312 and may be positioned such that the linkage 312 contacts the rotation stop when the linkage 312 is rotated to its intended farthest position.Alternatively or additionally, a rotation stop may be positioned adjacent to the extension / retraction member 316, the pivot connector 314, and / or the housing 318 such that the extension / retraction member 316, the pivot connector 314, and / or the housing 318 contact the rotation stop when the extension / retraction member 316, the pivot connector 314, and / or the housing 318 are rotated to their intended furthest positions. Alternatively or additionally, a rotation stop may be positioned on the linkage 312, the pivot connector 314, and / or the extension / retraction member 316 to limit the range of relative angles that the linkage 312 and the extension / retraction member 316 can occupy. In some embodiments, at least two rotation stops may be provided. One rotation stop may, for example, limit movement of the component beyond an intended “wheels down” configuration, and another rotation stop may, for example, limit movement of the component beyond an intended “wheels up” configuration.

[0039] While the above description provides an example of restricting linkage 312 from exceeding a substantially vertical orientation when moving to a "wheels down" configuration, the end stops may be positioned to provide any desired limit on the movement of the linear actuator and / or its connected components. For example, the end stops may alternatively or additionally restrict linkage 312 from rotating beyond an orientation corresponding to a "wheels up" configuration, i.e., an angle corresponding to the intended lift range of the corresponding wheel. This can advantageously help minimize the work done by the linear actuator in lifting the wheel by helping to ensure that the wheel is not lifted more than necessary to allow bot 100 to move laterally.

[0040] Advantageously, such one or more end stops can help minimize the force that needs to be borne by a particular component of the wheel positioning mechanism, such as the drive means of the linear actuator, due to, for example, the weight of the bot 100 or the weight of the panel 324 and wheels 116, 118 to which the linkage 312 in question is connected. The force, or a component thereof, may instead be at least partially borne by the end stop or a corresponding combination of end stops (e.g., on opposite sides of the bot 100). This can help extend the expected life of the linear actuator, as the force is at least partially borne by the end stop feature, rather than solely by the drive means of the linear actuator on the bot 100.

[0041] Instead of or in addition to the end stops described above, damping means can be provided, for example, on or within the linear actuator. The damping means can serve similar purposes as the end stops described above. For example, the damping means can help minimize the force that needs to be supported by the drive means of the linear actuator. The damping means can take the form of clamping means configured to clamp the extension / retraction member 316 to limit the extension / retraction member 316's retraction into or extension from the housing 318, thereby holding the extension / retraction member 316 in a predetermined position relative to the housing. The damping means may, for example, clamp the extension / retraction member 316 so that the linkage 312 remains in a substantially vertical configuration (i.e., 0° relative to the vertical). This can help ensure that the corresponding wheel does not unexpectedly move from a lowered configuration to an elevated configuration, or vice versa. The damping means may form part of the linear actuator and be a powered electromechanical component controllable as part of the linear actuator, or it may be a separate component controllable separately from the linear actuator.

[0042] Thus, the end stops and / or braking means can help support at least a portion of the weight of the bot 100 when the corresponding linear actuator is in a retracted (wheels down) configuration, i.e., a configuration in which the wheels corresponding to a given linear actuator are lowered and in contact with the tracks 22 a, 22 b on the storage grid 1, and / or at least a portion of the weight of the wheels 116, 118 and corresponding panel 324 when the corresponding linear actuator is in an extended (wheels up) configuration, i.e., a configuration in which the wheels corresponding to a given linear actuator are raised and not in contact with the tracks 22 a, 22 b on the storage grid 1. Preferably, each of the linear actuators includes similar or identical end stop and / or braking means features, and each of the end stop and / or braking means features of the four linear actuators is configured to support at least a portion of the weight of the bot 100 when the corresponding linear actuator is in a retracted (wheels down) configuration and / or at least a portion of the weight of the respective panel 324 and wheel when the corresponding linear actuator is in an extended (wheels up) configuration. Thus, the end stops and / or braking features can help hold the weight of the wheel when the drive means of the linear actuator is not engaged to apply a driving force to the extension / retraction member 316, and / or can help hold the weight of the wheel and the panel to which the wheel is mounted when the drive means of the linear actuator applies a driving force to the extension / retraction member 316 to extend the extension / retraction member 316 from its corresponding housing 318.

[0043] Latching means may be provided in addition to or as an alternative to the braking means and / or end stops described above. The latching means may serve to limit the movement of the wheels, particularly to or from a predetermined position. As a first example, the latching means may be provided in the form of a magnetic latch mechanism comprising two magnets, e.g., one mounted on the linkage 312 or roller 320 and the other mounted on the frame 324, which are attracted to each other and serve to hold each other and their respective components substantially together until a predetermined separation force is reached. As a second example, latching means may be provided in the form of a mechanical roller latch, such as a plunger ball roller (i.e., a ball mounted in a recess with a retractable feature that allows the ball to be pushed into the recess and out of the way of a component such as the roller 310) or another suitable feature or mechanism. The latching means provides resistance to movement of the roller 310 or another component connecting the linear actuator and the corresponding wheel 116, 118. For example, a roller latch may be provided in opening 322 of frame 320 such that when roller 310 moves into the "wheels up" configuration, its corresponding linear actuator moves roller 310 on the roller latch (pushing the roller latch down into its recess) and is restricted from moving back on the roller latch unless a force sufficient to overcome the roller latch and allow roller 310 to move to the "wheels down" configuration is applied to roller 310 (i.e., by the linear actuator). Thus, the latch can help hold the wheels in the "wheels up" configuration. Alternate or additional roller latches can be provided in appropriate locations such that when roller 310 moves into the "wheels down" configuration, its corresponding linear actuator moves roller 310 on the alternate or additional roller latch and is restricted from moving back on the alternate or additional roller latch unless a force sufficient to overcome the alternate or additional roller latch and allow roller 310 to move to the "wheels up" configuration is applied to roller 310 (i.e., by the linear actuator).Overcoming the roller latch may involve, for example, displacing a spring-loaded or biased component of the roller latch out of the way of the intended direction of movement of the roller 310. The spring or bias level of the roller latch may be selected to provide a resistance corresponding to forces the roller 310 may experience as a result of the weight of the panels and wheels involved in raising and lowering the roller 310, the weight of the bot 100, and / or forces that corresponding linear actuators may exert on the roller 310.

[0044] As noted above, the illustrated configuration of linear actuators configured to raise and lower each wheel 116, 118 relative to the body 102 of the bot 100 advantageously requires less power than, for example, a configuration in which substantially the entire weight of the bot 100 is lifted and supported to facilitate a change in the direction of movement of the bot 100 (e.g., by moving the second set of wheels downward relative to the body of the bot, bringing the second set of wheels into contact with the surface and moving the first set of wheels out of contact with the surface, the bot can move in one direction on the stationary first set of wheels when the body of the bot is in the relatively lowered configuration, and in another direction on the movable second set of wheels when the body of the bot is in the relatively raised configuration). In particular, in a configuration in which the illustrated linkage 312 is moved substantially vertically when the wheels 116, 118 are moved to the lowered configuration, the corresponding linear actuator may not need to support or lift more than the weight of the wheels 116, 118 and the components to which the wheels 116, 118 are mounted. The linear actuator may not be required to specifically lift the weight of the bot 100. This arrangement of components may advantageously reduce the performance requirements of the linear actuator, thereby reducing the cost of manufacturing and / or operating the bot (because the linear actuator may consume less power during its upstroke and downstroke than the linear actuator required to lift the entire weight of the bot). In embodiments in which linear actuators on adjacent sides of the bot 100 are configured to raise and lower their respective wheels substantially simultaneously (e.g., first and second linear actuators 188, 189 are configured to raise and lower their respective wheels 116, 118 substantially simultaneously, and / or vice versa), the linear actuator may be required to lift the weight of the bot 100, but may not need to lift the weight through as much distance as in embodiments with only a single set of moving wheels.

[0045] Advantageously, the illustrated configuration of the wheel positioning mechanism, which includes linear actuators and connected components located substantially external to and on the bottom 114 of the bot 100, may be relatively easy to install and remove, for example, during bot construction, service, or disassembly. The illustrated wheel positioning mechanism may provide a relatively “quick-release” wheel positioning mechanism that can be quickly removed from the bot 100 and / or a relatively “modular” wheel positioning mechanism that can be replaced with a replacement module as needed. This may be particularly true compared to bots that have wheel positioning mechanisms at least partially located on the top of the bot and therefore include longer components that extend through more of the bot to reach the wheels. Such a configuration may require a larger portion of the bot to be removed before the wheel positioning mechanism is sufficiently exposed for component removal or replacement. Additionally, the illustrated wheel positioning mechanism can facilitate access to other components housed within the body 102 of the bot 100, for example, by positioning the wheel positioning mechanism on the lower portion 114 of the bot 100, thereby allowing unobstructed access to other components housed within the body 102 of the bot 100.

[0046] The illustrated configuration can also advantageously consume relatively little space in the bot 100. The configuration can have, for example, a depth (e.g., a dimension into the bot in the y-direction for the first linear actuator 188 or the x-direction for the second linear actuator 189) of less than 50 mm. The configuration can more specifically have a depth of 40 mm to 45 mm, and in certain embodiments, a depth of 44 mm. The configuration can also have a relatively narrow width (e.g., a dimension along each side of the bot in the x-direction for the first linear actuator 188 or the y-direction for the second linear actuator 189) and / or a relatively low height (a dimension along each side of the bot in the z-direction for either of the linear actuators). Thus, the illustrated wheel positioning mechanism may be a relatively compact example of a wheel positioning mechanism for raising and lowering the wheels 116, 118 relative to the body 102 of the bot 100. This can advantageously mean that there is more space within the body 102 of the bot 100 in the upper portion 112 for the container accommodation space 120 and / or other components of the bot 100, such as larger power components 191 and / or larger versions of other types of components that may be housed within the body 102 of the bot 100, such as control components, drive components, and / or container lifting components. This may enable the bot to perform other aspects of its operations (such as raising or lowering the container 10 or moving along the tracks 22a, 22b) more quickly than a bot with less space for the corresponding components. Furthermore, maintenance of the bot 100 can be simplified because a wheel positioning mechanism with a relatively shallow depth, narrow width, and / or low height interferes less with other components of the bot 100 than alternative wheel positioning mechanisms.

[0047] In the illustrated configuration, the linear actuators and other components of the wheel positioning mechanism are visible, but one or more cover panels may be provided on the exterior of the bot to obscure and protect the components from view. The cover panels may be positioned to be easily removed and replaced, for example, to allow for maintenance or replacement of components within the bot 100. In other embodiments, the linear actuators and / or other components may be mounted on an exterior panel of the bot 100. In such embodiments, the linear actuators and / or other components are visible during normal use of the bot 100. The linear actuators and other components of the wheel positioning mechanism do not necessarily need to be provided inside the body 102 of the bot 100 (i.e., within the space defined by the body 102). They may instead be provided outside the body 102 of the bot 100, for example, mounted on the exterior surface of the body 102 but protected by cladding or other protective layers.

[0048] The upper and lower portions 112, 114 of the body 102 of the bot 100 are not necessarily bounded by the body 102 of the bot 100; they may, for example, include space around the outside of the body 102, such that components connected to the outside of the body 102 (such as a wheel assembly or wheel positioning mechanism) can be considered to be within the upper or lower portions 112, 114.

[0049] The body 102 of the bot 100 can include four shafts extending substantially in the z-direction, one near each corner of the body 102, to which the panels 324 can be slidably attached. For example, each panel 324 can include two sliding bearing openings or holes, one at each end of the panel 324, sized and positioned to receive the corresponding corner shaft. In such a configuration, two of the four panels 324 of the bot 100 are attached to each shaft. Each panel 324 can slide up and down the shaft as the linear actuators 188, 189 raise or lower the panel 324 (i.e., move it in the z-direction). The bearing openings or holes that accommodate the shafts can be located on complementary shaped portions of the panels 324. For example, each panel 324 can include a first reduced z-dimension portion at a lower-left position at one end of the panel 324 and a second reduced z-dimension portion at an upper-right position at the other end of the panel 324, with each reduced z-dimension (or "reduced height") portion including a respective bearing opening or hole for that end of the panel 324. The two reduced z-dimension portions can enable corresponding reduced z-dimension portions of adjacent panels 324 to accommodate the same shaft and be slidable up and down. This advantageously allows for only a single shaft to be present at each corner of the bot 100 to guide the panel 324 up and down relative to the rest of the body 102 of the bot 100, and the weight of the panel 324 can be reduced by the reduced z-dimension portions at the ends of the panel 324, thereby reducing the space and weight required for the wheel positioning mechanism and related components.

[0050] Alternatively or additionally, the body 102 of the bot 100 may include linear guides arranged to interact with corresponding linear guides mounted to or forming part of each panel 324 to allow the panels 324 to slide up and down. The linear guides may include, for example, dovetail features (e.g., a protrusion on the panel linear guide and a recess on the body linear guide, or vice versa) to allow the panels 324 to slide up and down while being guided by the linear guides.

[0051] The wheels 116, 118 are rotatably mounted to their respective panels 324 such that the wheels 116, 118 can rotate about their respective axes of rotation. This allows the bot 100 to move along the tracks 22a, 22b. Rather than raising and lowering the wheels relative to the panels, the panels are raised and lowered relative to the body 102 of the bot 100. In other words, the wheel assembly includes a chassis with panels on which the wheels can rotate but are otherwise fixedly mounted. Each panel of the wheel chassis is configured to move relative to the body 102 of the bot 100, causing the wheels 116, 118 to move relative to the body 102. The illustrated configuration, including such a chassis, can advantageously mean that the wheels 116, 118 are less likely to splay, pivot, or otherwise move out of their intended positioning or alignment to support the weight of the bot 100 and enable movement of the bot 100 along the tracks 22a, 22b than alternative configurations of wheel assemblies in which the wheels are arranged to move up and down relative to a panel or other structure to which they are mounted, resulting in the wheels' raising and lowering on the tracks 22a, 22b. This can mean that the wheels in the illustrated configuration are sturdier and / or more rigidly mounted, providing greater rigidity to the bot 100. This can help make the bot 100 more stable as it rests on and moves along the tracks 22a, 22b and / or transitions from a state configured to move in a first direction to a state configured to move in a second direction.

[0052] Advantageously, the linear actuators and other components of the wheel positioning mechanism for raising and lowering the wheels 116, 118 relative to the body 102 of the bot 100 may be positioned on the lower portion 114 of the bot 100, as illustrated in FIG. 3. This can advantageously help lower the center of gravity of the bot 100 and improve the stability of the bot. The wheel positioning mechanism may advantageously be positioned adjacent to the container accommodating space 120, substantially or completely below the top of the container accommodating space 120. Such a positioning can particularly advantageously help lower the center of gravity of the bot 100 when the container accommodating space 120 is empty or contains an empty or lightly loaded container 10. This positioning of the wheel positioning mechanism on the lower portion 114 of the bot 100 without significantly interfering with, colliding with, or obstructing the container accommodating space 120 or any containers 10 moving in or out of the container accommodating space 120 is made possible by selected components and selected orientations of the components, which allow the wheel positioning mechanism to have one or more relatively narrow dimensions, as described above. In other embodiments, one or more components of the wheel positioning mechanism may be positioned on the upper portion 112 of the bot 100.

[0053] Advantageously, each of the four linear actuators can be actuated independently of one another to independently control the positioning of the pairs of wheels 116, 118. This can enable a variety of advantageous functionality, such as raising and lowering individual pairs of wheels during movement of the bot 100 to conform to imperfections in the surfaces of the tracks 22a, 22b and / or to conform to intentional curvatures in the tracks 22a, 22b. The independent actuation of the linear actuators can, for example, facilitate or make easier movement on curved and / or inclined tracks, as well as on substantially straight, orthogonally arranged tracks, such as those illustrated on the storage grid 1 illustrated in FIG. 1. The wheel positioning mechanism can further include means for pivoting the wheels relative to their respective panels and / or relative to the body 102 of the bot 100 to help conform to the curved tracks 22a, 22b. This may include, for example, steering means for rotating the wheels to change the direction they face, and / or tilting means configured to allow the wheels to pivot about respective axes running substantially along or parallel to the direction of movement of the bot 100. These respective axes may, for example, run through the centers of the pair of wheels.

[0054] The extension and retraction of the linear actuators or alternative wheel engagement means may be controlled electrically, mechanically, pneumatically or otherwise to control the raising and lowering of the panel to which the respective wheel is mounted.

[0055] In some examples, the length of the linkage 312 on either side of the second pivot point P2 may be chosen to optimize lever action or rotational moment. For example, the distance between the pivot connector 314 (i.e., the point on the linkage 312 where the linear actuator force is applied) and the second pivot point P2 may be maximized to achieve a greater rotational moment from the same force provided by the linear actuator. Alternatively or additionally, the distance between the roller 310 and the second pivot point P2 may be minimized to reduce the rotational moment from the weight of the frame 320, panel 324, and wheel. In other words, the length of the linkage 312 on either side of the second pivot point P2 may be chosen to amplify the effect of the force provided by the linear actuator.

[0056] In the illustrated embodiment, the linkage 312 is straight. In other embodiments, the linkage need not be straight. For example, it may be angled (which in this context means having at least two differently oriented (i.e., mutually angled) sections, e.g., one on each side of the second pivot point P2, one or more of which may be straight) or curved. When the linkage is angled, the portion of the linkage below the second pivot point P2 may be restricted so that it cannot travel beyond the vertical or can only travel a small angle beyond the vertical (e.g., less than 5°, or preferably less than 1°), as described above in the context of the non-angled linkage 312. As described above, the linkage may be held in or near the vertical position by one or more end stops, braking means, or latching means. Advantageously, having an angled or curved linkage can allow further optimization of the rotational moment provided by the linear actuator. For example, properly angling the linkage allows the wheel positioning mechanism to be positioned so that, while the linear actuator applies a force to the linkage (e.g., when the linear actuator initially applies a force to the linkage to move it from a configuration in which the portion of the linkage below the second pivot point P2 is substantially vertical and / or when the linkage is approaching its farthest extent of rotation so that the corresponding wheel reaches its most elevated position), the linear actuator applies the force to the linkage at or near 90° for a greater or more significant time during the linkage's movement, thus maximizing the rotational moment or torque generated by the linear actuator's force, or optimizing the time during which the linear actuator can provide maximum rotational moment or torque (to apply maximum rotational moment at a relatively more significant time). This can help improve energy efficiency, shorten the time it takes the linear actuator to lift each wheel, and / or reduce the power requirements of the linear actuator.

[0057] Angled or curved linkages can further provide advantages with respect to an over-center locking configuration of the linkage and its connected components. Angled or curved linkages can also reduce the space occupied by the wheel positioning mechanism (e.g., in the x-direction in the case of the first linear actuator 188 or the third linear actuator, in the y-direction in the case of the second linear actuator 189 or the fourth linear actuator, and / or in the z-direction in the case of any of the linear actuators), thereby allowing more space for other components housed within the body 102 of the bot 100 or for the container accommodation space 120. Increasing the size of the container accommodation space 120 can advantageously mean that the bot 100 can fit a larger container 10, which can increase the number and / or volume of items that can be stored within the container 10 and manipulated by the bot 100.

[0058] Further optimization of the rotational moment provided by the linear actuator may be achieved through the relative positioning of pivot points P1 and P2. For example, proper relative positioning of pivot points P1 and P2 can mean that while the linear actuator applies a force to the linkage, the linear actuator applies the force to the linkage at or near 90° more of the time or more significantly the time (e.g., when the linear actuator first applies a force to the linkage to move the linkage from a configuration in which at least the portion of the linkage below second pivot point P2 moves away from vertical, and / or when the linkage is approaching the farthest extent of its rotation such that the corresponding wheel reaches its most elevated position), thus maximizing the rotational moment or torque generated by the linear actuator force.

[0059] 2-4 may be an integral part of or include the extension / retraction member 316, and may include additional components. For example, the pivot connector 314 may include a pair of apertured forks positioned at the end of the extension / retraction member 316 and a pin that passes through the apertures in the forks and corresponding apertures in the linkage 312. In such an embodiment, the upper ends of the pivot connector 314 and the linkage 312 may be constrained to translate together by the pin.

[0060] In the illustrated embodiment, a fully retracted configuration of the linear actuator and its associated components corresponds to a "wheels down" configuration, and a fully extended configuration of the linear actuator and its associated components corresponds to a "wheels up" configuration. This may be particularly advantageous when the linear actuator is capable of generating an extension force greater than a retraction force. However, in other embodiments, these configurations may be reversed; i.e., a fully retracted configuration of the linear actuator and its associated components may correspond to a "wheels up" configuration, and a fully extended configuration of the linear actuator and its associated components may correspond to a "wheels down" configuration. In one example of such a configuration, when the linear actuator is in the fully retracted configuration, the linkage may be in a pivoted position such that the second (lower) end of the linkage (to which the roller is rotatably mounted) is to the left of the second pivot point P2 and relatively high in the z-direction.

[0061] As the linear actuator extends the extension / retraction member from the housing toward the extended configuration, the roller moves in an arc about pivot point P2 downward and to the right as the linkage rotates about pivot point P2. The linkage can stop rotating (e.g., by a braking means or one or more end stops, as described above) when at least a lower portion of the linkage (below pivot point P2) reaches or just passes a substantially vertical orientation, at which point the roller can be at the lowest point of its arc. The corresponding frame, panel, and wheel can thus be in their lowered configuration. To move the wheels from the lowered configuration to their raised configuration, the linear actuator can retract the extension / retraction member, moving the linkage away from the configuration in which at least a lower portion of the linkage is in a vertical position. The roller therefore moves upward and to the left as the linkage rotates about pivot point P2, exerting an upward force on the frame, panel, and wheel, moving the wheel to the raised configuration.

[0062] As described above, the extension / retraction member 316 may still be at least partially within the housing 318 when the linear actuator and other components are in a "fully extended" configuration. Similarly, at least a portion of the extension / retraction member 316 may still protrude from the housing 318 when the linear actuator and other components are in a "fully retracted" configuration. The completeness of extension and retraction may be defined based on the intended maximum elevation or depression of the corresponding wheel 116, 118. The fully extended and fully retracted configurations may be separated by one or more end stops, as described above or otherwise.

[0063] A further embodiment of a wheel positioning mechanism is illustrated in FIG. 5. The example of FIG. 5 includes linear actuators 401 configured to be mounted on each side of the bot 100. Unlike the examples of FIGS. 2-4, the linear actuators 401 are configured to be fixedly (non-pivotally) mounted on each side of the bot 100. The linear actuators 401 are configured to apply extension and contraction forces to a first wedge 405 via extension and contraction members 403, driving the first wedge 405 in a direction substantially along or parallel to the x-axis illustrated in FIG. 5. A first linear guide 407 including a generally T-shaped protrusion is mounted on an inclined surface 411 of the first wedge 405. A second wedge 413 is mounted on a panel 415, which is substantially similar in function to the panel 324 described in FIGS. 2-4. A second linear guide 417 including a generally T-shaped recess is mounted on an inclined surface 421 of the second wedge 413. The generally T-shaped recess of the second linear guide 417 is sized, shaped, and configured to slidably receive the generally T-shaped protrusion of the first linear guide 407. In other words, the T-shaped protrusion and the T-shaped recess dovetail-engage with one another in a manner such that the T-shaped protrusion can slide along the T-shaped recess at least partially within the T-shaped recess in either direction. In some embodiments, one or more "end stop" features may be provided (e.g., at the longitudinal ends of the T-shaped recess) to limit the distance the T-shaped protrusion can slide.

[0064] Panel 415 is slidably mounted on body 102 of bot 100 such that panel 415 can slide up and down (i.e., in the z-direction) but cannot move in any other direction (i.e., cannot move in the x- or y-directions). Panel 415 may, for example, be slidably mounted on a shaft in a manner similar to how panel 324 is mounted, as described above, or may be mounted in a different manner but achieve a similar effect of allowing panel 415 to move only in the z-direction. Panel 415 may additionally or alternatively include one or more linear guides or other features arranged to interact with one or more corresponding linear guides mounted on body 102 of bot 100.

[0065] When the linear actuator 401 applies an extension force to the first wedge 405 via the extension and contraction member 403, the movement of the first wedge 405 is further restricted by a block 419 fixedly (immovably) mounted to the body 102 of the bot 100. The block 419 restricts the first wedge 405 from substantially moving in the z-direction because the block 419 is fixedly attached to the body 102 of the bot 100 directly above the first wedge 405. In other words, the block 419 prevents the first wedge 405 from moving in the z-direction. The block 419 can also contribute to restricting the first wedge 405 from substantially moving in the y-direction. In the illustrated embodiment, this is accomplished through interaction between a third linear guide 423 mounted on the underside of the block 419 and a fourth linear guide 425 mounted on the upper surface of the first wedge 405. The third and fourth linear guides 423, 425 are substantially similar to the first and second linear guides 407, 417, with one including a T-shaped protrusion extending longitudinally along its respective mounting component and the other including a T-shaped recess extending longitudinally along its respective mounting component. As described above with respect to the first and second linear guides, the T-shaped protrusion of the third or fourth linear guide 423, 425 can be positioned to slide at least partially within the T-shaped recess of the fourth or third linear guide 425, 423. Since the block 419 (fixedly mounted to the body 102 of the bot 100) cannot move in the y direction and the y-direction movement of the first wedge 405 relative to the block 419 is limited by the engagement between the T-shaped protrusion and the T-shaped recess, the longitudinal engagement between the T-shaped protrusion and the T-shaped recess can help ensure that the first wedge 405 cannot move substantially in the y direction.

[0066] Thus, when the linear actuator 401 applies an extension force to the first wedge 405 via the extension / contraction member 403, the first wedge 405 moves substantially only along or parallel to the x-direction. The first wedge 405 applies a corresponding force to the second wedge 413 via the first and second linear guides 407, 417. The force applied by the first wedge 405 to the second wedge 413 has components in the x- and z-directions (due to the angles of the inclined surfaces 411 and 421 on which the first and second linear guides 407, 417 are mounted). Because second wedge 413 is mounted to panel 415, which is mounted to body 102 of bot 100 such that panel 415 can slide only in the z-direction, the x-direction component of the force applied to second wedge 413 is attenuated by the shaft, linear slider, and / or other mounting means by which panel 415 is attached to body 102 of bot 100. The z-direction component of the force applied to second wedge 413 causes second wedge 413 and panel 415 to move downward relative to body 102 of bot 100. This causes the wheel (mounted to panel 415, as described above in the context of FIGS. 2-4) to move downward, for example, into contact with track 22a or 22b. The T-shaped protrusion of the first linear guide 407 slides within the T-shaped recess of the second linear slider 417 as the first wedge 405 slides in the x-direction (left side in Figure 5) and the second wedge 413 slides in the z-direction (bottom side in Figure 5).

[0067] When the linear actuator 401 applies a contraction force to the first wedge 405 via the extension / contraction member 403, the first wedge 405 moves along or approximately parallel to the x-axis, but in the opposite direction (to the right in FIG. 5 ). The first wedge 405 applies a corresponding force to the second wedge 413 via the first and second linear guides 407, 417. Specifically, the rightward movement of the first wedge 405 causes the T-shaped protrusion of the first linear guide 407 to apply a force to the T-shaped recess of the second linear guide 417, which is mounted to the second wedge 413. The force applied by the first wedge 405 to the second wedge 413 has components in the x-direction (to the right) and the z-direction (upward) depending on the angle of the inclined surfaces 411 and 421 on which the first and second linear guides 407, 417 are mounted. Because second wedge 413 is mounted to panel 415, which is mounted to body 102 of bot 100 in a manner that allows panel 415 to slide only in the z-direction, the x-direction component of the force applied to second wedge 413 is attenuated by a shaft, linear slider, or other mounting means that mounts panel 415 to body 102 of bot 100. The z-direction component of the force applied to second wedge 413 causes second wedge 413 and panel 415 to move upward relative to body 102 of bot 100. This causes the wheel (mounted to panel 415 as described above in the context of Figures 2-4) to move upward and out of contact with, for example, track 22a or 22b. When the first wedge 405 slides in the x-direction (to the right in FIG. 5) and the second wedge 413 slides in the z-direction (to the top in FIG. 5), the T-shaped protrusion of the first linear guide 407 slides within the T-shaped recess of the second linear slider 417.

[0068] While the above example shows a T-shaped protrusion on the first linear guide 407 and a T-shaped recess on the second linear guide 417, in other examples, the T-shaped protrusion may be on the second linear guide 417 and the T-shaped recess may be on the first linear guide 407. Additionally, in some examples, different shapes or cross-sectional profiles of the protrusion and / or recess may be used, provided that the arrangement of the protrusion and recess still allows the first wedge 405 to lift the second wedge 413 when the first wedge 405 is retracted by the linear actuator 401. For example, the cross-section of the protrusion may have a spool or shaft that results in a circular, oval, square, or other shaped portion, the shaped portion being positioned to engage a corresponding shaped recess in the other guide. The third and fourth linear guides 423, 425 may similarly have one or more dovetail features, which may be arranged in any manner that allows them to limit the movement of the corresponding first wedge 405 as described above.

[0069] Advantageously, in the example illustrated in FIGS. 2 through 5, the linear actuators of the wheel positioning mechanism are oriented non-vertically. In this context, the term "oriented" and its derivatives refer to the direction of actuation (i.e., extension and contraction) of the linear actuator and / or the direction of pointing the longitudinal axis of the linear actuator. More specifically, the linear actuators in the embodiment illustrated in FIG. 5 are oriented substantially horizontally. The linear actuators illustrated in FIGS. 2 through 4 may also be oriented substantially horizontally, but as noted above, are pivotally mounted so that each linear actuator can occupy a range of orientations. More specifically, the linear actuators of FIGS. 2 through 4 can occupy a range of orientations between approaching horizontal and vertical, or more specifically between horizontal and 45° from horizontal. This non-vertical orientation of the linear actuators advantageously means that vertical space consumed by the linear actuators is minimized, allowing more space within the upper section 112 for other components. A non-vertical orientation of a linear actuator can advantageously mean that the housing and extension / retraction members of a given linear actuator can fit substantially within the lower portion 114 of the body 102 of the bot 100 in a fully extended configuration, allowing more space for operating components (e.g., a larger battery 191) in the upper portion 112 of the body 102 of the bot 100. Additionally, as described above, a non-vertical orientation of a linear actuator can allow mechanical advantage to be utilized, for example, using a pivot lever (such as linkage 312) and / or another rotational component that allows a larger rotational moment to be provided using the linear actuator, or using gearing means that magnify the input from the linear actuator to the output to lift a wheel relative to the body of the bot.

[0070] Although in the above paragraphs the third and fourth linear guides 423, 425 are described and illustrated as restricting the movement of the first wedge 405 so that it cannot move in the y-direction, one or more further, not shown, components (such as side panels of the bot 100) can be provided in addition to or as an alternative to the linear guides to help constrain the movement of the first wedge 405.

[0071] One or more of the linear guides may be made of or may include a layer of low friction material to help facilitate sliding of the respective linear guides relative to one another.

[0072] Although a new reference number (401) is used to identify the linear actuator illustrated in Figure 5, the linear actuator 401 may be substantially the same as either or both of the linear actuators 188, 189 illustrated in the examples of Figures 2-4. Instead of a pivot connector 314, the linear actuator 401 illustrated in Figure 5 has a first wedge 405 attached to the distal end of the extension / retraction member 403.

[0073] Further embodiments of bot 100 are described having wheel positioning mechanisms with non-vertically mounted linear actuators. In further embodiments, one or more of the wheels in the wheel assembly (i.e., one or more of the wheels 116 in the first set of wheels 116 and / or one or more of the wheels 118 in the second set of wheels 118) are pivotally mounted on body 102 of bot 100 at a pivot point offset in the plane of the wheel from the axis of the wheel about which the wheel rotates as bot 100 moves along track 22a or 22b. The pivot point can be described as eccentric, i.e., away from the center of the wheel. A linear actuator (such as linear actuator 318, 401 illustrated in FIGS. 2-5, or a different form of linear actuator) is pivotally mounted on body 102 of bot 100, with the distal end of the linear actuator's extension / retraction member connected to a pivotally mounted wheel 116 or 118, such that extension or retraction of the extension / retraction member causes wheel 116, 118 to pivot about an eccentric pivot point. This pivoting causes wheel 116, 118 to rotate eccentrically (i.e., about the eccentric pivot point), lowering or raising the lowest point of wheel 116, 118 as wheel 116, 118 traces an arc about the eccentric pivot point. As the linear actuators are extended or retracted, the lowering or raising of the lowest points of the wheels 116, 118 allows the wheels to contact or clear the corresponding tracks 22a, 22b, facilitating a change in the direction of movement of the bot 100 along the tracks 22a, 22b of the storage grid 1. The other wheels 116, 118 on the same side of the bot 100 as the previously described wheels 116, 118 may also be pivotally mounted to the body 102 of the bot 100 about an eccentric pivot point and may include respective linear actuators that are also pivotally mounted to the body 102 of the bot 100 and connected at the distal ends of their extension / retraction members to the pivotally mounted wheels 116, 118. The two linear actuators may be controlled to extend or retract substantially simultaneously to lower or raise the two wheels 116, 118 substantially simultaneously.The wheels 116, 118 on one or more of the other sides of the bot 100 may similarly be pivotally mounted with respective pivotally mounted linear actuators, or may use one of the other types of wheel positioning mechanisms described herein, or may instead be immovably fixed to the body 102 of the bot 100, relying on raising or lowering a wheel on an adjacent side to cause the body 102 of the bot 100 to lower or raise. Thus, this embodiment includes a wheel positioning mechanism and wheel engagement means that may be described as an eccentrically rotating base. Eccentric rotation of one or more components of the wheel positioning mechanism causes the wheels 116, 118 to raise and / or lower.

[0074] In a further variation of the embodiment described in the previous paragraph, both of a pair of wheels 116, 118 on one side of the body 102 of the bot 100 may be eccentrically mounted on the body 102 of the bot 100 (i.e., about respective points offset from the center of the wheels in the plane of the wheels), and a single linear actuator may be connected between the two wheels, e.g., to a point opposite the center of the wheels from the eccentric mounting point. Thus, extension or contraction of the single linear actuator can eccentrically rotate both of the wheels 116, 118 about their respective eccentric mounting points, causing the lowest points of the wheels 116, 118 to lower or raise. This can move the wheels 116, 118 into or out of contact with the tracks 22a, 22b, facilitating changes in the direction of travel of the bot 100. Other pairs of wheels on the bot 100 may be similarly eccentrically mounted and each may have a respective single linear actuator connected to both wheels of each pair, or may have one or more of the other wheel positioning mechanisms described herein. In a further variation, two linear actuators may be rigidly connected to one another between the wheels 116, 118. This can advantageously provide greater extension and / or retraction than a single linear actuator. Therefore, this variation also includes a wheel positioning mechanism and wheel engagement means, which may be described as an eccentrically rotating base. Eccentric rotation of one or more components of the wheel positioning mechanism causes the wheels 116, 118 to raise and / or lower.

[0075] FIG. 6 illustrates a further example of a wheel positioning mechanism configured to raise and lower a wheel relative to the body 102 of the bot 100. In the illustrated example, a rotational motor 601 configured for mounting on and / or within the body 102 of the bot 100 is provided. A rotational output shaft 603 of the motor 601 is configured to be inserted into an opening 605 of a bearing 606. The bearing 606 is rotatably mounted within the connector 607 toward a first end 608 of the connector 607. The output shaft 603 and opening 605 may be configured to allow rotation to be transmitted between the output shaft 603 and the bearing 606 through the opening 605. For example, the output shaft 603 and opening 605 may have a high-friction surface, such as a knurled, stippled, or otherwise textured surface, to provide sufficient friction between the two surfaces to allow rotational force to be transmitted from the output shaft 603 to the opening 605 and, therefore, to the bearing 606. In some embodiments, the surfaces of output shaft 603 and opening 605 may be keyed and / or grooved to allow rotational forces to be transmitted. In some embodiments, a high friction coating may be applied to the surfaces of output shaft 603 and opening 605. In some embodiments, the fit between output shaft 603 and opening 605 may be sufficient to allow rotational forces to be transmitted.

[0076] When the output shaft 603 engages the opening 605, the motor 601 rotates the output shaft 603 about its longitudinal axis. The rotation of the output shaft 603 rotates the bearing 606 about the longitudinal axis of the output shaft 603 and the center of the opening 605. As shown in FIG. 6 , the center of the opening 605 is eccentric (i.e., offset from the center of the bearing 606), so rotating the bearing 606 about the center of the opening 605 causes the center of the bearing 606 to rise or fall, i.e., eccentric rotation of the bearing 606. As the bearing rotates within the connector 607, the center of the bearing 606 rises or falls, causing the connector 607 to correspondingly rise or fall. In the illustrated embodiment, an additional bearing (not visible behind the frame 613) is rotatably mounted within the connector 607 from the bearing 606 toward the second, opposite end 609 of the connector 607. The further bearing is connected to a frame 613 mounted on panel 617 at one or more connection points 611 (portions of frame 613 are cut away to show connectors 611 in the further bearing). Connection points 611 may be, for example, openings in frame 613 through which bolts, pins, or other fastening means may be driven to secure frame 613 and the further bearing together and restrict the frame 613 and the further bearing from translational movement together. Panel 617 may be substantially similar in function to panels 324, 415 described and illustrated in the context of Figures 2-4 and 5.

[0077] Rotation of the output shaft 603 about its longitudinal axis causes the bearing 606 to rotate eccentrically about the center of the opening 605, and therefore the connector 607 moves up and down and side to side at its first (upper) end 608 to accommodate the eccentric rotation of the bearing 606, and additional bearings rotate within the connector 607 to accommodate the side to side movement of the top end of the connector 607, and move up and down (with the connector 607 and frame 613) to accommodate the up and down movement of the connector 607. Upward or downward movement of the additional bearings causes the frame 613 and panel 617 to move up or down. A wheel is rotatable but otherwise fixedly mounted to the panel 617, and the wheel moves up and down with the frame 613 and panel 617. Rotation of the output shaft 603 of the motor 601 therefore causes the wheel mounted on the panel 617 to raise or lower, moving the wheel out of contact with or into contact with the tracks 22 a, 22 b of the storage grid 1.

[0078] The wheel positioning mechanism and wheel engagement means illustrated in FIG. 6 may therefore be referred to as an eccentric rotation based wheel positioning mechanism / wheel engagement means, because the rotation bearing 606 rotates about an eccentric axis to raise or lower the rotatably mounted connector 607, which in turn raises or lowers the indirectly connected wheel.

[0079] In the modified embodiment of the wheel positioning mechanism illustrated in FIG. 6 , the motor 601 can have an output shaft that rotates about an axis offset from the center of the output shaft. As the motor rotates, the motor's output shaft describes an arc. The motor's output shaft may be rotatably inserted into an opening in the first (top) end of the connector 607. As the motor's output shaft is rotated by the motor, the output shaft moves the opening in the connector 607 through the arc of the circle that the output shaft moves. This raises and lowers the first (top) end of the connector 607, causing a corresponding rise and lowering of the frame 613 and panel 617, similar to the rise and lowering of the connector 607 that occurred in the embodiment illustrated in FIG. 6 . Therefore, this modified embodiment can also be referred to as an eccentric rotation-based wheel positioning mechanism / wheel engagement means. This can be considered similar to a crank and cam action.

[0080] Bot 100 may be provided with four such eccentric cam-based wheel positioning mechanisms to cause the raising and lowering of pairs of wheels on each of the four sides of bot 100. Alternatively, bot 100 may be provided with one or more eccentric cam-based wheel positioning mechanisms as illustrated in FIG. 6 and one or more alternative wheel positioning mechanisms, such as the wheel positioning mechanisms illustrated in FIGS. 2 through 5.

[0081] While the example of an eccentric rotation-based wheel positioning mechanism illustrated in FIG. 6 includes a motor 601 configured to rotate an output shaft 603 and a bearing 606 engaged with the output shaft 603 about its longitudinal axis, other examples may include different rotation means for providing eccentric rotation of one or more components that effect the raising and lowering of the bot's wheels. For example, in some embodiments, a non-vertically mounted linear actuator (such as linear actuators 188 and 189 illustrated in FIGS. 2-4) may be pivotally mounted on the body 102 of the bot 100 and connected to the rotatable bearing 606 at the distal end of the linear actuator's extension / retraction member using a pin that protrudes through one of the openings in the bearing 606. An additional pin mounted on the body 102 of the bot 100 may protrude through one of the openings in the bearing 606. The extension and / or contraction of the linear actuator then causes bearing 606 to eccentrically rotate about a pin mounted to body 102, causing the connector 607 to raise or lower and move side to side as bearing 606 rotates. The raising or lowering of connector 607 due to the eccentric rotation of bearing 606 causes a corresponding raising or lowering of panel 617 to which the wheel is mounted, thereby raising or lowering the wheel so that it is out of contact with or can contact tracks 22 a, 22 b. Thus, this embodiment may also be referred to as having an eccentric rotation-based wheel positioning mechanism / wheel engagement means.

[0082] In another embodiment, a motor or other rotation generating means may be mounted to the body 102 of the bot 100 and connected via a shaft through an eccentrically mounted wheel (e.g., at a point on the opposite side of the wheel from the eccentric mounting point). Rotation of the rotation generating means may cause the shaft to apply a force to the wheel, causing the wheel to rotate eccentrically about its eccentric mounting point, raising or lowering the wheel's lowest point. In some embodiments, the rotation generating means may be connected via a shaft to two wheels on one side of the bot 100. Rotation of the rotation generating means may cause eccentric rotation of both wheels, simultaneously raising or lowering the lowest points of the two wheels and allowing the wheels to contact or not contact the tracks 22a, 22b. Because the wheels rotate about an eccentric mounting point, this embodiment may also be referred to as having an eccentric rotation-based wheel positioning mechanism / wheel engagement means.

[0083] A variation of a rotation-based wheel positioning mechanism is illustrated in FIG. 7. The illustrated mechanism incorporates a motor 701 or other rotation generating means similar to that shown in FIG. 6. The output 703 of motor 701 is positioned in a hole 705 in cam 707. Cam 707 is adjacent to a cylinder 709 mounted on a shaft 711. Shaft 711 is connected to a wheel mounting frame 713. A spring 715 biases shaft 711, cylinder 709, and wheel mounting frame 713 upward. Cam 707 controls the extent to which spring 715 can continue to lift wheel mounting frame 713 under the action of motor 701 and motor output 703. In FIG. 7, cam 707 is illustrated in its "extended" configuration. In other words, the long axis of cam 707 is oriented substantially vertically, so that cylinder 709, shaft 711, and wheel mounting frame 713 are lowered as fully as possible. This may be the configuration required, for example, for a wheel mounted to wheel mounting frame 713 to contact track 22 of storage system 1. Spring 715 is held at its minimum extension and maximum potential energy. When cam 707 rotates away from this substantially vertical orientation, cylinder 709, shaft 711, and wheel mounting assembly 713 rise under the influence of spring 715, converting potential energy into extension. Advantageously, the illustrated configuration can allow for relatively rapid raising and lowering of the corresponding wheel, since, depending on the specific dimensions and other physical characteristics of cam 707 and cylinder 709, a small change in the angle of the long axis of cam 707 relative to the vertical can result in a relatively large change in the vertical displacement of wheel mounting frame 713. Furthermore, because the raising occurs under the influence of spring 715 and the lowering occurs under the rotational action of motor 701, this may be a relatively low-energy method of raising and lowering the corresponding wheel, which can be in line with the overall benefits of the system. Depending on the desired configuration, the cylinder 709 may be rotatably mounted such that as the angle of the long axis of the cam 707 changes, the cylinder rotates along the outer surface of the cam 707 .In other embodiments, the mating surfaces of the cam 707 and cylinder 709 may be configured to slide against one another. In such instances, the surfaces may be smooth to allow for easy sliding, or may be provided with a desired level of friction to provide more controlled relative movement of the cam 707 and cylinder 709. The wheel mounting frame 713 may be mounted on the body 102 of the load handling apparatus 100 within guides that prevent diagonal (sideways) movement of the frame 713 but allow vertical movement of the frame 713.

[0084] A further example of a wheel positioning mechanism is illustrated in FIG. 8. In the illustrated example, a pump system 801 provides pressurized fluid (such as mineral oil or other fluid) to a chamber system 803. The pressure of the fluid in the chamber system 803 controls the force applied to a plunger 805. The plunger 805 is connected to a wheel mounting frame 807, similar to the wheel mounting frame 713 illustrated in FIG. 7. The force applied to the plunger 805 by the fluid 803 in the chamber system 803 controls the extent to which the wheel mounting frame 807 is lowered. The plunger 805 can act like a piston, defining a boundary between an upper and lower chamber in the chamber system 803, and the pressure and / or flow of the fluid in each of the upper and lower chambers of the chamber system 803 is controlled under the action of the pump system 801 to control the extent to which the wheel mounting frame 807 is depressed, lowering the wheel toward the track 22 of the storage system 1. In some embodiments, the vertical position of wheel mounting frame 807 may be controlled solely by pump system 801, chamber system 803, and plunger 805. In other embodiments, other components or systems may contribute to controlling the vertical position of wheel mounting frame 807. For example, in some embodiments, a spring, such as spring 715 illustrated in FIG. 7, may be provided to bias wheel mounting frame 807 in a predetermined direction. In such cases, springs and systems 801, 803, and 805 may oppose each other or act in the same direction, depending on specific design choices and requirements. The configuration illustrated in FIG. 8 may be considered a fluid-based wheel positioning mechanism comprising a fluid-based wheel engagement means. The fluid properties (such as volume and / or compressibility) may be chosen to optimize the speed of action (i.e., raising and lowering of wheel mounting frame 807 and associated wheels), the efficiency of action (i.e., the input energy to pump system 801), and / or other factors.

[0085] Some embodiments of the load handling apparatus may include two or more of the above types of wheel positioning mechanisms for raising and lowering different pairs of wheels. For example, the load handling apparatus may include a wheel positioning mechanism, such as that shown in FIGS. 2-4, on a first side of the load handling apparatus for raising and lowering a pair of wheels on the first side, a wheel positioning mechanism, such as that shown in FIG. 5, on a third side of the load handling apparatus for raising and lowering a pair of wheels on the third side, a wheel positioning mechanism, such as that shown in FIG. 6, on a second side of the load handling apparatus for raising and lowering a pair of wheels on the second side, and a wheel positioning mechanism, such as that shown in FIG. 7, on a fourth side of the load handling apparatus for raising and lowering a pair of wheels on the fourth side. Some embodiments may include two different types of wheel positioning mechanisms, for example, a first type of wheel positioning mechanism on sides 1 and 2 of the load handling apparatus and another type of wheel positioning mechanism on sides 3 and 4 of the load handling apparatus, such that the same type of wheel positioning mechanism is configured to raise and lower all of the wheels in the first set of wheels 116 and the same type of wheel positioning mechanism is configured to raise and lower all of the wheels in the second set of wheels 118. Some embodiments may include only one type of wheel positioning mechanism, for example, the wheel positioning mechanisms illustrated in Figures 2 through 4 may be present on both sides of the load handling apparatus.

[0086] As used herein, the term "n-way movement" (and related expressions) (where n is, for example, one of x, y, and z) is intended to mean movement substantially along or parallel to the n-axis in either direction (i.e., toward the positive end of the n-axis or toward the negative end of the n-axis).

[0087] As used herein, the term "connected" and its derivatives are intended to encompass the possibilities of direct and indirect connections. For example, "x is connected to y" is intended to encompass the possibilities of x being directly connected to y with no intervening components, and the possibilities of x being indirectly connected to y with one or more intervening components. When a direct connection is intended, the terms "directly connected," "directly connected," or similar are used.

[0088] As used herein, the term "comprise" and its derivatives are intended to have an inclusive rather than exclusive meaning. For example, "x comprises y" is intended to include the possibility that x contains only y, multiple y, or one or more y and one or more other elements. When an exclusive meaning is intended, the phrase "x consists of y" is used, meaning that x contains only y and nothing else.

Claims

1. 1. A load handling apparatus (100) for lifting and moving containers (10) stacked in stacks (12) in a storage system (1), said storage system (1) including a plurality of rails or tracks (22) arranged in a grid pattern above said stacks (12) of containers (10), said load handling apparatus (100) configured to move on said rails or tracks (22) above said stacks (12), said load handling apparatus (100) comprising: a body (102) having an upper portion (112) and a lower portion (114), the upper portion (112) configured to accommodate one or more operating components, the lower portion (114) disposed below the upper portion (112), the lower portion (114) comprising a container accommodating space (120) for accommodating at least one container (10); a wheel assembly arranged to support the body (102), the wheel assembly comprising: a first set of wheels (116) for engaging a first set of rails or tracks (22a) to guide movement of the device (100) in a first direction; and a second set of wheels (118) for engaging a second set of rails or tracks (22b) to guide movement of the device (100) in a second direction, wherein the second direction is transverse to the first direction; a container lifting mechanism, the container lifting mechanism comprising: a container engaging means configured to engage a container (10); and a lifting means configured to raise and lower the container engaging means relative to the container accommodating space (120); a wheel positioning mechanism, the wheel positioning mechanism comprising wheel engagement means for selectively engaging the first set of wheels (116) with the first set of rails or tracks (22 a) or the second set of wheels (118) with the second set of rails or tracks (22 b), the wheel engagement means configured to raise or lower the first set of wheels (116) or the second set of wheels (118) relative to the body (102), thereby enabling the load handling apparatus (100) to selectively move in either the first direction or the second direction across the tracks (22 a, 22 b) of the storage system (1); A load handling apparatus (100) wherein said wheel engaging means comprises at least one non-vertical linear actuator.

2. The load handling apparatus (100) of claim 1, wherein the wheel positioning mechanism is located on the lower portion (114) of the body (102).

3. 3. The load handling apparatus (100) of claim 1 or 2, wherein the wheel positioning mechanism is located on or near an exterior surface of the body (102).

4. 4. The load handling apparatus (100) of claim 1, 2 or 3, wherein the wheel engaging means comprises a linkage, a pivot connector, and a roller configured to move under the action of the at least one non-vertical linear actuator to raise or lower the first set of wheels (116) or the second set of wheels (118) relative to the body (102).

5. 5. The load handling apparatus (100) of claim 4, wherein the linkage is angled.

6. 4. The load handling apparatus (100) of claim 1, 2 or 3, wherein the wheel engaging means comprises one or more wedges configured to move under the action of the at least one non-vertical linear actuator to raise or lower the first set of wheels (116) or the second set of wheels (118) relative to the body (102).

7. 4. The load handling apparatus (100) of claim 1, 2 or 3, wherein the at least one non-vertical linear actuator is connected between two wheels (116, 118) on a side of the load handling apparatus (100).

8. 8. The load handling device (100) of claim 1, wherein the body (102) includes one or more substantially vertically oriented shafts, and wherein at least two panels (324) are slidably mounted on each of the one or more substantially vertically oriented shafts.

9. 9. The load handling apparatus (100) of claim 1, wherein the wheel positioning mechanism includes one or more brake, latch and / or stop means configured to limit movement of the first set of wheels (116) and / or the second set of wheels (118) to or from a raised or lowered configuration.

10. A method for enabling a load handling device (100) comprising a body (102) and a wheel assembly including a first set of wheels (116) and a second set of wheels (118) to move across a lateral set of tracks (22a, 22b) of a storage grid (1), wherein the first set of wheels (116) are movable relative to the body (102) by a wheel positioning mechanism comprising wheel engagement means, the method comprising: providing wheel engagement means below the body (102) including at least a first non-vertical linear actuator configured to raise and lower the wheels of the first set of wheels (116) out of contact with and into contact with the tracks of the first set of tracks (22a); and controlling the first non-vertical linear actuator to lower a wheel of the first set of wheels (116) into contact with a track of the first set of tracks (22a).

11. The second set of wheels (118) is movable relative to the body (102) of the load handling apparatus (100) by the wheel positioning mechanism, and the method comprises: providing at least a second non-vertical linear actuator below the body (102) configured to raise and lower the wheels of the second set of wheels (118) out of contact with and into contact with the tracks of the second set of tracks (22b); and controlling the second non-vertical linear actuator to raise the wheels of the second set of wheels (118) out of contact with the tracks of the second set of tracks (22b) to enable the load handling apparatus (100) to move on the first set of wheels (116) along the tracks of the first set of tracks (22a).

12. 1. A computer program for enabling movement of a load handling apparatus (100) comprising a body (102) and a wheel assembly including a first set of wheels (116) and a second set of wheels (118) across a lateral set of tracks (22a, 22b) of a storage grid (1), the first set of wheels (116) being movable relative to the body (102) by a wheel positioning mechanism comprising wheel engagement means, the wheel engagement means including at least a first non-vertical linear actuator configured to raise and lower wheels of the first set of wheels (116) out of contact with and into contact with the tracks of the first set of tracks (22a), the computer program comprising instructions that, when executed by a computer, cause the computer to: a computer program product causing the computer to execute the step of controlling at least the first non-vertical linear actuator to lower a wheel of the first set of wheels (116) into contact with a track of the first set of tracks (22a).

13. the second set of wheels (118) are movable relative to the body (102) of the load handling apparatus (100) by the wheel positioning mechanism comprising wheel engagement means, the wheel engagement means further comprising at least a second non-vertical linear actuator configured to raise and lower the wheels of the second set of wheels (118) out of contact with and into contact with the tracks of the second set of tracks (22b), and the computer program includes instructions that, when executed by a computer, cause the computer to:

13. The computer program of claim 12, further comprising the step of controlling at least the second non-vertical linear actuator to raise wheels of the second set of wheels (118) out of contact with the tracks of the second set of tracks (22b) to enable the load handling apparatus (100) to move on the first set of wheels (116) along the tracks of the first set of tracks (22a).

14. 1. A load handling apparatus (100) for lifting and moving containers (10) stacked in stacks (12) in a storage system (1), said storage system (1) including a plurality of rails or tracks (22) arranged in a grid pattern above said stacks (12) of containers (10), said load handling apparatus (100) configured to move on said rails or tracks (22) above said stacks (12), said load handling apparatus (100) comprising: a body (102) having an upper portion (112) and a lower portion (114), the upper portion (112) configured to accommodate one or more operating components, the lower portion (114) disposed below the upper portion (112), the lower portion (114) comprising a container accommodating space (120) for accommodating at least one container (10); a wheel assembly arranged to support the body (102), the wheel assembly comprising: a first set of wheels (116) for engaging a first set of rails or tracks (22a) to guide movement of the device (100) in a first direction; and a second set of wheels (118) for engaging a second set of rails or tracks (22b) to guide movement of the device (100) in a second direction, wherein the second direction is transverse to the first direction; a container lifting mechanism, the container lifting mechanism comprising: a container engaging means configured to engage a container (10); and a lifting means configured to raise and lower the container engaging means relative to the container accommodating space (120); a wheel positioning mechanism, the wheel positioning mechanism comprising wheel engagement means for selectively engaging the first set of wheels (116) with the first set of rails or tracks (22 a) or the second set of wheels (118) with the second set of rails or tracks (22 b), the wheel engagement means comprising movement means configured to raise or lower the first set of wheels (116) or the second set of wheels (118) relative to the body (102), thereby enabling the load handling apparatus (100) to selectively move in either the first direction or the second direction across the tracks (22 a, 22 b) of the storage system (1); A load handling apparatus (100) wherein said wheel engagement means comprises eccentric rotation based wheel engagement means.

15. The eccentric rotation base wheel engagement means comprises: A rotating means (601); a connector (607) connected to a wheel of said first set of wheels (116) or said second set of wheels (118); a bearing (606) rotatably mounted in or on said connector (607); 15. The load handling apparatus (100) of claim 14, wherein the rotating means (601) is configured to cause eccentric rotation of the rotatable bearing (606), the eccentric rotation of the rotatable bearing (606) causing a raising or lowering of the connector (607), corresponding to a raising or lowering of a wheel of the first set of wheels (116) or the second set of wheels (118).

16. 16. The load handling apparatus (100) of claim 15, wherein the eccentric rotation based wheel engagement means further comprises a further bearing (615) fixedly connected to the first or second set of wheels (116, 118), the further bearing (615) being rotatably mounted in or on the connector (607) to accommodate movement of the connector (607).

17. 17. The load handling apparatus (100) of claim 14, 15 or 16, wherein the wheel positioning mechanism is located on the lower portion (114) of the body (102).

18. 18. A load handling apparatus (100) according to any one of claims 14 to 17, wherein the wheel positioning mechanism is located on or near an exterior surface of the body (102).

19. 19. A cargo handling device (100) according to any one of claims 14 to 18, wherein the body (102) includes one or more substantially vertically oriented shafts, and wherein at least two panels (617) are slidably mounted on each of the one or more substantially vertically oriented shafts.

20. 20. A load handling apparatus (100) according to any one of claims 14 to 19, wherein the wheel positioning mechanism includes one or more brake, latch and / or stop means configured to limit movement of the first set of wheels (116) and / or the second set of wheels (118) to or from a raised or lowered configuration.

21. A method for enabling a load handling device (100) comprising a body (102) and a wheel assembly including a first set of wheels (116) and a second set of wheels (118) to move across a lateral set of tracks (22a, 22b) of a storage grid (1), wherein the first and second sets of wheels (116, 118) are movable relative to the body (102) by a wheel positioning mechanism comprising wheel engagement means, the method comprising: providing wheel engagement means on a lower portion of said body (102) including at least a first eccentrically rotating based wheel engagement means configured to raise and lower the wheels of said first set of wheels (116) out of contact with and into contact with the tracks of said first set of tracks (22a); and controlling said first eccentric rotating based wheel engaging means to lower wheels of said first set of wheels (116) into contact with tracks of said first set of tracks (22a).

22. The second set of wheels is movable relative to the body (102) of the load handling apparatus (100) by the wheel positioning mechanism, and the method includes: providing at least a second eccentrically rotating based wheel engagement means on a lower portion of said body (102) configured to raise and lower the wheels of said second set of wheels (118) out of contact with and into contact with the tracks of said second set of tracks (22b); 22. The method of claim 21, further comprising controlling the second eccentrically rotating based wheel engaging means to lift the wheels of the second set of wheels (118) out of contact with the tracks of the second set of tracks (22b) to enable the load handling apparatus (100) to move on the first set of wheels (116) along the tracks of the first set of tracks (22a).

23. 1. A computer program for enabling movement of a load handling apparatus (100) comprising a body (102) and a wheel assembly including a first set of wheels (116) and a second set of wheels (118) across a lateral set of tracks (22a, 22b) of a storage grid (1), said first set of wheels (116) being movable relative to said body (102) by a wheel positioning mechanism comprising wheel engagement means, said wheel engagement means including at least a first eccentrically rotating based wheel engagement means configured to raise out of contact with and lower into contact with tracks of said first set of tracks (22a), said computer program comprising instructions that, when executed by a computer, cause said computer to: a computer program causing the computer to execute the step of controlling at least a first eccentric cam based wheel engaging means to lower a wheel of said first set of wheels (116) into contact with a track of said first set of tracks (22a).

24. the second set of wheels (118) being movable relative to the body (102) of the load handling apparatus (100) by the wheel positioning mechanism comprising wheel engagement means, the wheel engagement means further comprising at least a second eccentrically rotating based wheel engagement means configured to raise and lower the wheels of the second set of wheels (118) out of contact with and into contact with the tracks of the second set of tracks (22b), the computer program comprising instructions that, when executed by a computer, cause the computer to:

24. The computer program of claim 23, further comprising the step of controlling at least the second eccentrically rotating based wheel engagement means to lift the wheels of the second set of wheels (118) out of contact with the tracks of the second set of tracks (22b) to allow the load handling apparatus (100) to move on the first set of wheels (116) along the tracks of the first set of tracks (22b).

Images