Cam mechanism for a redirection assembly of a load handling device and related methods and uses

Abstract

Load handling device, method and kit of parts for a load handling device. A load handling device for lifting and moving storage containers stacked on a framework structure of a grid-based storage system, comprising a first set of parallel rails or tracks and a second set of parallel rails or tracks extending substantially perpendicular to the first set of rails or tracks in a substantially horizontal plane to form a grid pattern with a plurality of grid spaces, wherein the grid is supported by the set of uprights to form a plurality of vertical storage locations below the grid such that the containers are stacked between the uprights vertically through the plurality of grid spaces and guided by the uprights, the load handling device having a top, a bottom, and an intermediate harrow between the top and bottom. a framework comprising a frame defining a volume for moving the intermediate harrow around a first set of wheels disposed on a lower portion of the framework and a second set of wheels disposed on a lower portion of the framework, the first set of wheels disposed to engage with the first set of parallel tracks and the second set of wheels disposed to engage with the second set of parallel tracks, and a diverting assembly disposed to raise or lower the first set of wheels relative to the framework and / or lower or raise the second set of wheels relative to the framework to engage and disengage the first and second sets of wheels with the parallel tracks, the diverting assembly being located between the intermediate harrow and the first set of wheels and / or the second set of wheels, wherein the diverting assembly comprises a cam mechanism.

Description

[Technical Field]

[0001] The present invention relates to an apparatus for a redirection assembly, and more particularly, but not exclusively, the present invention relates to a cam mechanism. [Background technology]

[0002] A robotic load handling device is described in UK Patent Application No. GB2520104A (Ocado Innovation Limited). Such load handling devices are controllably moved on a track system that forms a grid over a stack of bins or containers. A given load handling device lifts a target container from the top of the stack, the target container containing the inventory item needed to fulfill a customer order. The load handling device includes a first set of wheels and a second set of wheels for engaging with x-direction and y-direction tracks, respectively. To move in the x-direction, the x-direction wheels are engaged with the tracks, while the y-direction wheels are elevated. Similarly, to move in the y-direction, the y-direction wheels are engaged with the tracks and the x-direction wheels are elevated. The transition between x-direction and y-direction movement is controlled by a change-over mechanism.

[0003] A mechanism for enabling lateral movement of a load handling device in the lateral direction by selectively engaging x-direction wheels or y-direction wheels is described in WO2017153583A1 (Ocado Innovation Limited).

[0004] It is essential that the diverting mechanism be sturdy, reliable, capable of supporting the weight of the load handling device and target container, and able to withstand repeated use.

[0005] It is against this background that the present invention was conceived. Summary of the Invention

[0006] Aspects of the invention are set out in the accompanying claims.

[0007] One object is to provide a lightweight load handling device. Another object is to provide a low-cost load handling device. Another object is to provide a modular load handling device that is easy and / or inexpensive to assemble and maintain. Another object is to provide a load handling device that is made primarily from recyclable or environmentally friendly materials.

[0008] In one aspect of the present invention, a load handling device is provided for lifting and moving storage containers stacked in a grid-based storage system framework structure, the framework structure comprising a first set of parallel rails or tracks and a second set of parallel rails or tracks extending substantially perpendicular to the first set of rails or tracks in a substantially horizontal plane to form a grid pattern comprising a plurality of grid spaces, wherein the grid is supported by a set of upright members to form a plurality of vertical storage locations below the grid as containers are stacked between and guided by the upright members vertically through the plurality of grid spaces, and the load handling device is configured to lift and move storage containers at an upper, lower, and intermediate harrows between the upper and lower. a skeleton including a frame defining a volume having an intermediate harrow (halo); a first set of wheels disposed on a lower portion of the skeleton and a second set of wheels disposed on a lower portion of the skeleton, the first set of wheels disposed to engage with a first set of parallel tracks and the second set of wheels disposed to engage with a second set of parallel tracks, and a diverting assembly disposed to raise or lower the first set of wheels relative to the skeleton and / or lower or raise the second set of wheels relative to the skeleton to engage and disengage the first and second sets of wheels with the parallel tracks, the diverting assembly being located between the intermediate harrow and the first set of wheels and / or the second set of wheels, wherein the diverting assembly comprises a cam mechanism.

[0009] The storage system may be an automated or semi-automated storage and retrieval system. The grid-based storage system framework structure may be a high density cubic storage system.

[0010] The cargo handling devices, or bots, may be autonomous or semi-autonomous devices that operate on a grid.

[0011] On the load handling device, the first set of wheels and the second set of wheels may be independently drivable relative to each other. When the load handling device is driven, only one set of wheels is engaged with the grid, thereby enabling movement of the load handling device along the track to any point on the grid by driving only the set of wheels engaged with the track. A diverting assembly allows for selection of the wheels that engage the track.

[0012] It will be appreciated that engagement and disengagement of the first set of wheels or the second set of wheels with the tracks requires vertical movement of that set of wheels while the other set of wheels supports the load handling device.

[0013] The skeleton may be considered to be the body of the load handling device and may be substantially free of cladding or sides. For convenience, it may be useful to think of the skeleton in parts, where the upper portion may be used to support or house components such as batteries, communications, control systems, and motors, and the lower portion may be used primarily for the drive system or may be substantially empty space for receiving containers. An intermediate harrow may connect the lower portion and upper portion and provide additional rigidity to the skeleton.

[0014] Considering a redirection assembly, generally, a cam or linear cam is a simple mechanism for converting a linear input into a different motion. The cam profile may be formed on one or more edges or surfaces and may comprise a slot, groove, or surface shape. Thus, a cam may be arranged to convert horizontal motion into vertical motion by comprising a vertical element and a horizontal element.

[0015] The cam mechanism can allow positive engagement between a selected set of wheels and the track.

[0016] The profile of the cam mechanism may not have discontinuities, for example, the cam profile may be shaped to provide a sinusoidal acceleration profile. In this way, the transition between engagement and disengagement may be smooth or jerk-free. Furthermore, the transition may require a smooth force input.

[0017] The location of the diverting assembly between the intermediate halo and the wheel set, i.e., in the lower part of the framework, can mean that the transmission of forces from the diverting assembly to the wheels is substantially direct, i.e., there are no long linkages that are likely to result in mechanical losses due at least in part to bending moments and torques.

[0018] It will be appreciated that the cam path or profile can be directly related to the vertical movement required to engage and disengage the wheels from the track. Therefore, a diverting assembly based on a cam mechanism can be vertically compact. As a result, the directing mechanism can be positioned so that it does not extend vertically beyond the intermediate harrow and can be substantially shorter than the vertical height of the intermediate harrow. This allows for greater flexibility in positioning other components of the load handling device. For example, reducing the height of the diverting assembly can allow the intermediate harrow to be widened, thereby increasing the overall rigidity of the framework. Furthermore, reducing the height can keep the center of mass of the load handling device as low as possible, thereby improving the stability of the load handling device, especially when operating on a grid.

[0019] It will be appreciated that horizontally mirrored cam profiles may be required on the y-direction side of the load handling device compared to the x-direction side of the load handling device.

[0020] It will be appreciated that because cams are relatively simple mechanical devices, the number of parts required for a diverting assembly can be minimized. With fewer parts, the diverting assembly can advantageously have improved tolerances. It will be appreciated that, generally, as the number of parts increases, the parts will need to be manufactured more precisely to ensure that they fit together or the overall tolerances of the assembly do not become unacceptable.

[0021] The cam mechanism includes a traveler, a fixed brace, a cam, and a follower, the traveler arranged to move relative to the fixed brace under an applied horizontal force, and the follower engageable with the cam to convert movement of the traveler into vertical movement.

[0022] It will be appreciated that these may be typical components of a cam mechanism.

[0023] The follower may be attached to a fixed brace and the cam may be connected to a traveler, or the follower may be attached to a traveler and the cam may be connected to a fixed brace.

[0024] It will be appreciated that either configuration can provide equivalent transfer of horizontal to vertical motion, and that a vertically mirrored cam profile may be required depending on which arrangement is selected.

[0025] The fixed brace may comprise a wheel chassis for mounting the first set of wheels or the second set of wheels of the pair, respectively.

[0026] The wheels may be fixed directly or substantially directly to the diverting assembly, in this way no additional components are required and mechanical losses between the diverting assembly and the wheels can be minimized.

[0027] The fixed brace may be constrained to the frame by one or more fixtures so that it moves only vertically.

[0028] In this way, out-of-plane vertical movement of the cam mechanism and / or wheel chassis is prevented, ensuring that substantially all horizontal input is used to convert into vertical movement to engage and disengage the wheels.

[0029] The cam may be a linear cam, the cam may comprise a slot, or the cam may comprise a surface.

[0030] It will be appreciated that a linear type cam may be arranged to follow a single edge, such as a surface, or the follower may be constrained between two edges, such as a slot.

[0031] The slot configuration may have the advantage of ensuring that the follower continues to follow the cam profile in both the forward and reverse directions.

[0032] The follower may comprise a roller or slider supported by the cover.

[0033] In the case of a sliding cam, the follower may be a rigid protrusion with no degrees of freedom. Friction losses between the follower and the cam can be reduced by selecting low friction materials or by using lubricants.

[0034] In the case of rollers or rolling means, the follower may be provided with a bearing.

[0035] The follower may be supported on each side by a cover.

[0036] It will be appreciated that by holding the follower between two covers, a slight compressive force can be applied to the follower, which can help keep the follower vertically aligned with the cam.

[0037] The cam mechanism may comprise a single cam arrangement, or the cam mechanism may comprise a double cam arrangement.

[0038] The cam mechanism may include an engagement means between the traveler and the fixed brace. For example, the traveler may include an engagement foot that engages with a corresponding base on the fixed brace or wheel mount. Typically, the foot is positioned to engage with the base when in the drive position. The engagement between the foot and the base provides increased stiffness to the side. The increased stiffness can increase the stability and controllability of the load handling device. Such an arrangement is particularly useful in a single cam arrangement.

[0039] In a double cam configuration, the cam mechanism may include two horizontally spaced and connected cam surfaces and corresponding followers on the traveler and fixed brace. In this manner, each of a pair of wheels may have a corresponding cam. This may provide the advantage of ensuring better balance and / or support of the wheel base or chassis, as the pair of wheels is raised and lowered at two points. It will be appreciated that this may reduce rotation of the wheel base.

[0040] The cam mechanism may comprise a triple cam arrangement.

[0041] It will be appreciated that any number of cam configurations may be provided across the sides of the device.

[0042] A triple cam configuration is advantageous when the load handling device is heavier and the wheels support a greater load. It will be appreciated that the load may be distributed across each of the cams.

[0043] The cam mechanisms may be located in a single vertical plane between the intermediate harrow and each wheel pair.

[0044] It will be appreciated that the traveler, fixed brace, cam, and follower may be in the same vertical plane. In this manner, the cam mechanism can occupy only the horizontal space required for the width or depth of the component. Therefore, the required horizontal space can be minimized, thereby substantially maximizing the empty volume of the framework. Maximizing the horizontal available space for load handling devices can be important for grid-based storage systems, where the system is designed so that a load handling device substantially occupies only a single grid space, allowing other load handling devices operating on the grid to pass through adjacent grid spaces, thereby maximizing the efficiency of the system.

[0045] In this way, the cam mechanism may substantially comprise a side of the skeleton structure, it being understood that other components may also be present on the side of the skeleton, but the skeleton may remain substantially open.

[0046] Each pair of the first set of wheels and the second set of wheels may be driven by a drive belt, and the cam mechanism may be located within an area defined by a path of the drive belt.

[0047] In this manner, the cam mechanism may substantially interlock, intersect, or overlap with other systems of the load handling device, and it will be appreciated that this arrangement may reduce the required volume within the framework for components and systems.

[0048] The cam mechanism may further include spring means between the traveler and the fixed brace.

[0049] Spring means may help bias the fixation brace into a preferred vertical position. For example, a spring means can bias the traveler and fixed brace together against the influence of gravity. Such an arrangement may be particularly useful where the cam includes a single edge or surface rather than a slot. In this manner, the spring means can ensure that the follower remains substantially engaged with the cam profile.

[0050] A first limit of the cam mechanism may define a raised wheel position and a second limit of the cam mechanism may define a lowered wheel position.

[0051] It will be appreciated that the cam profile may extend between a first limit and a second limit. For example, if the cam profile is a slot, the first limit may be a first end of the slot and the second limit may be a distal end of the slot. In the case of a single-sided surface or edge, the cam profile may be limited by a protrusion or discontinuity.

[0052] In use, the follower may have freedom to move between a first limit and a second limit. When using the cam mechanism as part of a diverting assembly, the first limit may correspond to a wheels-up or wheels-up position and the second limit may correspond to a wheels-down or wheels-down position. In the up position, the wheels may be disengaged or clear of the tracks, and in the down position, the wheels may be engaged with the tracks.

[0053] The steering assembly may be configured to raise or lower the first set of wheels and synchronously lower or raise, respectively, the second set of wheels relative to the framework.

[0054] For a load handling device to move in the x or y direction on the grid, it may be necessary to have only one set of wheels engaged with the tracks, and therefore it may be advantageous to raise a first set of wheels substantially simultaneously with lowering a second set of wheels, or vice versa.

[0055] In other configurations, it may be advantageous to ensure that the load handling device is supported throughout the transition between engagement of the first set of wheels or the second set of wheels. In this way, when changing from the first set of wheels to the second set of wheels, the first set of wheels is maintained in a lowered position, while the second set of wheels is lowered. When the second set of wheels engages the tracks, the first set of wheels is raised. Thus, the center of gravity of the bot is maintained throughout the turning operation, and the turning motor does not have to work against the weight of the load being carried.

[0056] The respective cam mechanisms may be mechanically connected to move in unison between a wheels-up configuration and a wheels-down configuration.

[0057] It will be appreciated that the diverting assembly may include a respective cam mechanism for each pair of wheels located on each side of the load handling device. By mechanically linking the respective cam mechanisms, it may be possible to substantially coordinate the vertical movement of the first set of wheels and the second set of wheels. Furthermore, it may be possible to operate the vertical movement with a single actuation.

[0058] The mechanical connection or linkage may be a belt or chain. The belt may be routed substantially around the periphery of the framework and attached to the traveler of each cam mechanism. In this manner, as the belt is rotated or driven, the traveler moves with it, providing a horizontal input to the cam mechanism. The belt arrangement may be relatively inexpensive and relatively lightweight.

[0059] In another configuration, the mechanical connection may be a lead screw located on each side of the load handling device. Each screw may be connected by a 90-degree bevel gear. Such an arrangement may be used without a gearbox, as the gear can be provided by the pitch of the screw. The screws on opposite sides of the load handling device may be arranged to operate in the same direction, or the screws on opposite sides may be arranged to operate in opposite directions.

[0060] The diverting assembly may be operated by a single motor, or the diverting assembly may be operated by two or more motors.

[0061] In this way, a single motor may be used to change the direction of movement of the load handling device. It will be appreciated that the motor may be replaced with any means of activation, such as, for example, a solenoid, hydraulic means, pneumatic means, servo means, solid state actuation means, etc. Advantageously, this may reduce the overall cost and weight of the load handling device.

[0062] When two or more motors are used, the load handling device may have some redundancy so that the load handling device can continue to operate even if there is a partial failure of the load handling device, thus avoiding a complete failure of the maneuverability of the load handling device on the grid. Advantageously, a more robust turning mechanism is provided. Advantageously, this reduces downtime of individual load handling devices and the storage and retrieval system as a whole.

[0063] The load handling device may further comprise sensing means for determining engagement of the first set of wheels or the second set of wheels with the parallel track.

[0064] Thus, proper functioning of the diverter assembly can be detected.

[0065] The load handling device may further comprise sensing means for determining a malfunction or failure of the turning assembly.

[0066] In the event of a turnaround assembly failure, if a single set of wheels is engaged with the track, the load handling device can be moved to the edge of the grid for recovery and repair, and if the load handling device is unable to move, a communication for recovery and repair can be communicated to the storage system control facility.

[0067] At least a portion of the cam mechanism may be 3D printed and / or at least a portion of the cam mechanism may be substantially topologically optimized.

[0068] In this way, it may be possible to achieve shapes or complex geometries that are not possible with more traditional forms of manufacturing. Advantageously, the cam mechanism may be printed on-demand or at a 3D printing facility near where the part is needed, thereby minimizing the logistical costs of transporting parts to where they are needed. It will be understood that 3D printing as referred to herein may more generally be referred to as additive manufacturing, which involves adding material layer on layer.

[0069] It is possible to print parts that contain two or more materials. In this way, some areas may have low friction for sliding or rolling efficiency, while other areas may have materials with properties selected for stiffness and strength. Thus, a cam mechanism may be load-bearing and may comprise part of a complex part. For example, the cam mechanism and chassis and other side features may be printed as a single part.

[0070] It may be possible to print two or more parts of the cam mechanism together as a single print with multiple parts, thus minimizing tolerance imperfections between the parts.

[0071] The cam mechanism may be substantially topologically optimized. In this way, the cam mechanism may be optimized to reduce the total amount of material used, and therefore mass. Alternatively, the cam mechanism may be optimized to stay within certain stress limits to ensure that the cam mechanism operates below its fatigue limit within the operating temperature range.

[0072] The load handling device may further comprise a lifting device supported by the top of the framework for lifting the container into the volume.

[0073] Thus, the cargo handling device may be used to retrieve the storage container.

[0074] The load handling device may further comprise means for sensing its position on the grid. The load handling device may further comprise means for lifting the storage container. The load handling device may further comprise means for transporting the lifted storage container to a position on the grid. The load handling device may further comprise means for identifying multiple storage containers. The load handling device may further comprise means for identifying a single storage container. The load handling device may be autonomously mobile without continuous direction from a centralized control utility. The load handling device may be remotely piloted under control of the storage system. The load handling device may further comprise means for communicating a signal to the centralized control utility and may be mobile under control of the centralized control utility. The load handling device may further comprise means for providing power to the turning assembly. The load handling device may further comprise a drive assembly. The load handling device may have wheels driven by belts. The load handling device may further comprise identification means.

[0075] In another aspect, there is provided a method for altering engagement between a set of wheels and a track of a load handling device according to the preceding claims, wherein the load handling device operates on a grid framework (14) structure comprising the track, the method comprising the steps of applying a force to a traveler of a diverting assembly in a first direction F1 to move a cam mechanism to a first limit, or applying a force to a traveler of the diverting assembly in a second direction F2 to move the cam mechanism to a second limit.

[0076] In another aspect, a kit of parts for modular assembly of a load handling device is provided, the kit comprising: a framework, a first set of wheels, and a second set of wheels, wherein the framework is attached to the first set of wheels and the second set of wheels, and at least one diverting assembly comprises at least one cam mechanism, each cam mechanism having a traveler, a fixed brace, a follower, and a cam path.

[0077] Thus, the load handling device may be modular: systems and components of the load handling device may be substantially interchangeable.

[0078] The part fixture may further comprise at least two cam mechanisms and a transport belt.

[0079] The component fixture may include at least one direction-changing motor.

[0080] At least one part may be 3D printed.

[0081] The part fixture may further comprise at least one of a set of wheels, a drive assembly, a gripper assembly, a lifting assembly, a communication system, and / or sensor means.

[0082] Other variations and advantages will become apparent from the following description. [Brief explanation of the drawings]

[0083] These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings. [Figure 1] FIG. 1 illustrates the storage structure. [Figure 2] FIG. 2 illustrates the track structure. [Figure 3] FIG. 3 illustrates a robotic load handling device on top of the storage structure illustrated in FIG. [Figure 4] FIG. 4 illustrates a robotic load handling device or bot. [Figure 5] FIG. 5 illustrates a robotic load handling device or bot. [Figure 6]Figure 6 illustrates a load handling device and turning assembly, with the load handling device parked in Figure 6a, the x-direction wheels raised while the y-direction wheels are lowered for movement in the y-direction in Figure 6b, and the y-direction wheels raised while the x-direction wheels are lowered for movement in the x-direction in Figure 6c. [Figure 7] FIG. 7 illustrates the diverting cam mechanism. [Figure 8] Figure 8a illustrates the cam mechanism of Figure 7 in a lowered position, Figure 8b illustrates the cam mechanism of Figure 7 in a rest position, and Figure 8c illustrates the cam mechanism of Figure 7 in a raised position. [Figure 9] FIG. 9 illustrates a double cam mechanism. [Figure 10] Figure 10a illustrates the double cam mechanism of Figure 9 in a lowered position, Figure 10b illustrates the double cam mechanism of Figure 9 in a stopped position, and Figure 10c illustrates the double cam mechanism of Figure 9 in a raised position. [Figure 11] FIG. 11 illustrates the triple cam mechanism. [Figure 12] Figure 12 illustrates an inverted cam mechanism, where in Figure 12a the follower is attached to the traveler and the cam is defined on the fixed brace, and in Figure 12b the cam is defined on the traveler and the follower is attached to the fixed brace. [Figure 13] Figure 13a illustrates the edge or surface cam mechanism in a lowered position, Figure 13b illustrates the edge or surface cam mechanism in a stopped position, and Figure 13c illustrates the edge or surface cam mechanism in a raised position. [Figure 14] FIG. 14 illustrates an inverted version of the surface cam mechanism illustrated in FIG. [Figure 15] FIG. 15 illustrates a side view of the cam and wheel mount arrangement. [Figure 16] FIG. 16 illustrates a front view of the cam and wheel mount arrangement. [Figure 17]Figure 17 illustrates a cam mechanism with anti-rotation legs, Figure 17a having the cam attached to the traveler and Figure 17b having the cam attached to the fixed brace. [Figure 18] Figure 18(af) illustrates a cam mechanism with anti-rotation legs similar to that illustrated in Figure 17, with the traveler in a different position, Figure 18(ac) having the cam attached to the traveler and Figure 18(df) having the cam attached to a fixed brace. [Figure 19] Figure 19 illustrates the difference between a cam mechanism with anti-rotation legs, Figure 19(ac), and a cam mechanism without anti-rotation features, Figure 19(df), where Figures 19(a,d) illustrate when the bot is moving and under acceleration, Figures 19(b,e) illustrate when the bot is moving and not accelerating, and Figures 19(c,f) illustrate when the bot is moving and under deceleration.

[0084] In the drawings, like features are indicated by like reference numerals where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0085] The following embodiments represent preferred examples of how the present invention may be practiced, but they are not necessarily the only examples of how it may be achieved. These examples are described in sufficient detail to enable one skilled in the art to practice the present invention. Other examples may be utilized, and structural changes may be made, without departing from the scope of the present invention, as defined by the appended claims. Furthermore, directional references and any other terms having an implied direction are provided by way of example to aid the reader's understanding of the specific examples described herein. They should not be read as requirements or limitations, particularly regarding the position, orientation, or use of the present invention, unless specifically recited in the appended claims. Similarly, connection references (e.g., attached, coupled, connected, joined, fixed, etc.) should be interpreted broadly and may include intermediate members between the connection of elements and the relative movement between the elements. Thus, connection references do not necessarily imply that two elements are directly connected and in a fixed relationship to each other, unless specifically recited in the appended claims. Similarly, the phrase "movement in the n-direction," where n is one of x, y, and z (and related phrases) 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).

[0086] FIG. 1 illustrates a storage structure 1 comprising upright members 3 and horizontal members 5, 7 supported by upright members 3. Horizontal members 7 extend parallel to each other and parallel to the illustrated x-axis, and horizontal members 5 extend parallel to each other and parallel to the illustrated y-axis, transverse to horizontal members 7. Upright members 3 extend parallel to each other and parallel to the illustrated z-axis. Horizontal members 5, 7 form a grid pattern defining a plurality of grid cells. In the illustrated example, containers 9 are arranged in stacks 11 beneath the grid cells defined by the grid pattern, one stack 11 of containers 9 per grid cell.

[0087] FIG. 2 shows an enlarged plan view of a section of a track structure 13 that forms part of the storage structure 1 illustrated in FIG. 1 and is located on top of the horizontal members 5, 7 of the storage structure 1 illustrated in FIG. 1. The track structure 13 may be provided by the horizontal members 5, 7 themselves (e.g., formed in or on the surfaces of the horizontal members 5, 7) or by one or more additional components attached to the top of the horizontal members 5, 7. The illustrated track structure 13 includes x-direction tracks 17 and y-direction tracks 19. In this case, a first set of tracks 17 extends in the x-direction, and a second set of tracks 19 extends in the y-direction transverse to the first set of tracks 17. The tracks 17, 19 define apertures 15 in the centers of the grid cells. The apertures 15 are sized to allow containers 9 located below the grid cells to be lifted and lowered through the apertures 15. The first set of tracks 17 are provided in pairs separated by ridges 21, and the second set of tracks 19 are provided in pairs separated by ridges 23. Other arrangements of the track structure are possible.

[0088] Figure 3 shows multiple robotic load handling devices 31 moving across the top of the storage structure 1 illustrated in Figure 1. Each load handling device 31, which may also be referred to as a robot 31 or bot 31, is provided with a turning assembly (not shown) and a set of wheels for engaging a corresponding x-direction track 17 or y-direction track 19 to enable the bot 31 to move across the track structure 13 and reach a particular grid cell. As mentioned above, the sets of tracks 17, 19 are separated by ridges 21, 23 that allow pairs of bots 31 to occupy adjacent grid cells or pass each other without colliding.

[0089] 4, the bot 31 comprises a body 33 having one or more components therein or attached thereto that enable the bot 31 to perform its intended functions. These functions may include moving about the storage structure 1 on the track structure 13 and raising or lowering containers 9 (e.g., from or to stacks 11) so that the bot 31 can retrieve or place containers 9 at specific locations defined by a grid pattern.

[0090] To perform the foregoing functions, the bot 31 comprises a first set of wheels 35 and a second set of wheels 37, which are attached to the body 33 of the bot 31 and enable the bot 31 to move in the x and y directions along the tracks 17 and 19, respectively. In particular, two wheels 35 are provided on the short side of the bot 31 visible in FIG. 4 , and two additional wheels 35 are provided on the opposite short side of the bot 31. The wheels 35 are rotatably attached to the body 33 and configured to engage with the track 17 to enable the bot 31 to move along the track 17. Similarly, two wheels 37 are provided on the long side of the bot 31 visible in FIG. 4 , and two additional wheels 37 are provided on the opposite long side of the bot 31. The wheels 37 engage with the track 19 and are rotatably attached to the body 33 of the bot 31 to enable the bot 31 to move along the track 19.

[0091] To enable the bot 31 to move in first and second directions on different wheels 35, 37, the bot 31 includes a wheel positioning mechanism for selectively engaging the first set of wheels 35 with the first set of tracks 17 or the second set of wheels 37 with the second set of tracks 19. The wheel positioning mechanism is configured to raise and lower the first set of wheels 35 and / or the second set of wheels 37 relative to the body 33, thereby enabling the load handling device 31 to selectively move in either the first direction or the second direction across the tracks 17, 19 of the storage structure 1.

[0092] The wheel positioning mechanism may include one or more linear actuators, rotary components, or other means for raising and lowering at least one set of wheels 35, 37 relative to the body 33 of the bot 31 to move at least one set of wheels 35, 37 away from and into contact with the tracks 17, 19. In some examples, only one set of wheels is configured to raise and lower, such that the act of lowering one set of wheels can effectively lift the other set of wheels away from the corresponding tracks, while the act of raising one set of wheels can effectively lower the other set of wheels into contact with the corresponding tracks. In other examples, both sets of wheels may be raised and lowered, advantageously meaning that the body 33 of the bot 31 remains at substantially the same height, thus eliminating the need for the weight of the body 33 and components mounted thereon to be raised and lowered by the wheel positioning mechanism.

[0093] To facilitate this latter function, the bot 31 further comprises container lifting means, generally designated 39, configured to raise a container 9 from the stack 11 into a container receiving space or cavity of the bot 31 and lower a container 9 from the container receiving space onto the stack 11. The illustrated container lifting means 39 comprises four tapes or reels 41 connected at their lower ends to container gripping assemblies 43. The tapes 41 may be wound up or unwound as required to raise or lower the container engaging assemblies 43. One or more motors or other means may be provided to effect or control the winding or unwinding of the tapes 41.

[0094] As can be seen in FIG. 5 , the illustrated body 33 of the bot 31 includes an upper portion 45 and a lower portion 47 of the upper portion 45. The upper portion 45 is configured to accommodate one or more operating components (not shown). The lower portion 47 is disposed below the upper portion 45 and includes a container receiving space or cavity for receiving at least a portion of a container 9 lifted by the container lifting means 39. The container receiving space is sized so that the container 9 can fit sufficiently within the cavity to allow the bot 31 to move across the track structure 13 above the storage structure 1 without the underside of the container 9 getting caught on the track structure 13 or another portion of the storage structure 1. When the bot 31 reaches its intended destination, the container lifting means 39 controls the tape 41 to lower the container gripping assembly 43 and corresponding container 9 out of the cavity within the lower portion 47 and to its intended location. The intended location may be a stack 11 of containers 9 or an exit point of the storage structure 1 (or an entrance point of the storage structure 1 if the bot 31 moves to collect a container 9 for storage within the storage structure 1). In the illustrated example, the upper portion 45 and the lower portion 47 are separated by a physical divider, although in other embodiments the upper portion 45 and the lower portion 47 may not be physically separated by a particular component or part of the body 33 of the bot 31.

[0095] The cargo handling device is described as a single (grid) spatial bot (cargo handling device) by way of example, but it will be understood that the automated or semi-automated storage and retrieval system is not limited to systems intended to use a single spatial bot.

[0096] In some embodiments, the container storage space of the bot 31 may not be within the body 33 of the bot 31. For example, in some embodiments, the container storage space may be adjacent to the body 33 of the bot 31 (e.g., in a cantilever configuration with the weight of the body 33 of the bot 31 counterbalancing the weight of the container being lifted). In such embodiments, the frame or arm of the container lifting means 39 may protrude horizontally from the body 33 of the bot 31, and the tape / reel 41 may be disposed at respective positions on the protruding frame and configured to be raised and lowered from those positions to raise and lower the container into the container storage space adjacent the body 33. The height at which the frame is attached to and protrudes from the body 33 of the bot 31 may be selected to provide a desired effect. For example, it is preferable that the frame protrude at a high level above the body 33 of the bot 31 so that a relatively large container or multiple containers can be lifted into the container storage space below the frame. Alternatively, the frame may be arranged to protrude lower below the body 33 (but high enough to accommodate at least one container between the frame and the track structure 13) to keep the center of mass of the bot 31 lower when the bot 31 is loaded with containers.

[0097] In contrast to cantilever bots, by locating the large components of the load handling device above the container accommodating space, the footprint of the load handling device is reduced compared to the cantilever design described in NO 317366, where the large components are housed in vehicle modules located to one side of the container accommodating space. Advantageously, the load handling device of the present invention occupies space above a corresponding number of stacks in the frame as vehicle modules and containers are lifted.

[0098] In the present invention, because the container load is suspended between a pair of wheels on each side of the vehicle, the single-spaced load handling device can also provide improved stability, increased load handling capacity, and reduced weight compared to prior art load handling devices of the cantilever type.

[0099] 4 and 5, the container engaging assembly 43 includes a gripper plate 49 attached to a lower end of the tape 41 and one or more gripper assemblies (not shown) mounted thereon for latching to the container 9. For example, the gripper assemblies, which may be provided at corners of the gripper plate 49 near the tape 41, are aligned with and positioned to interact with recesses or openings in the container 9 when actuated to latch to the container 9.

[0100] Referring more particularly to aspects of the wheel positioning mechanism or diverting assembly, FIG. 6 illustrates a perspective view of the load handling device 102 having the diverting assembly 110 in three positions: park position, y-transfer position, and x-transfer position.

[0101] In Figure 6a, both the x-direction wheel chassis 116 and the y-direction wheel chassis 118 are down so that all wheels are engaged with the tracks when the load handling device is positioned on the grid structure as described above. In Figure 6b, the x-direction wheel chassis 116 is raised and the y-direction wheel chassis 118 is lowered for movement in the y direction, and in Figure 6c, the y-direction wheel chassis 118 is raised and the x-direction wheel chassis is lowered for movement in the x direction. Each of the wheel chassis 116, 118 is moved vertically by connection to the turning assembly 110, as described in more detail below. The wheel chassis 116, 118 are at the same vertical or z-direction height in the parked position.

[0102] The diverter assembly includes mechanisms on each side of the load handling device 102. In Figure 6, mechanisms are shown on the visible x-direction side, with similar mechanisms located on the opposite x-direction side (not shown). Similarly, mechanisms are shown on the visible y-direction side, with similar mechanisms located on the opposite y-direction side (not shown). Each linkage set or diverter assembly 110 is connected to a corresponding wheel chassis 116, 118 on a particular side.

[0103] Figure 7 shows a cam mechanism 120 for use in a redirection assembly of the type described in relation to Figure 6, for example. The cam mechanism 120 comprises a traveler 121, a fixed brace 122, a cam profile 123 arranged as a slot in a face surface of the traveler 121, and a follower 124 that engages the cam 123 and extends between the opposing face or cover of the fixed brace 122. It will be appreciated that the fixed brace 122 may be made from a single piece or block having a depth sufficient to have a slot that accommodates the depth of the traveler 121 and configured to hold the follower 124 in place, or the fixed brace 122 may be made from two planes of material clamped together with the follower 124 fixed therebetween.

[0104] The cam or slot profile 123 extends between a first limit 125 and a second limit 126. Between these limits, as shown, the slot extends substantially horizontally from the first limit 125, slopes upward, and then continues substantially horizontally to the second limit 126 with sufficient space to accommodate the follower 124.

[0105] In the illustrated first configuration of the cam mechanism 120, the traveler 121 is movable horizontally and fixed vertically, while the fixed brace 122 is fixed horizontally and movable vertically. Thus, as the cam 123 moves horizontally across the follower from the first limit 125 to the second limit 126, the fixed brace 122 rises an amount equal to the vertical change in the cam profile 123. Alternatively, it will be appreciated that in a second configuration, the fixed brace 122 is movable horizontally while fixed vertically, and the traveler 121 is fixed horizontally and movable vertically. The relative positions between the traveler 121 and fixed brace 122 in the first configuration are illustrated in FIG. 8, which shows the cam 120 in various positions.

[0106] Figures 8a-8c illustrate the cam mechanism of Figure 7 with the front face of the fixed brace 122 removed to make it easier to see and understand the position of the follower 124. A vertical dotted line is positioned through the follower 124 to aid in understanding the relative position of the cam mechanism 120 between the figures.

[0107] 8a, the traveler 121 is positioned horizontally to the right. A follower 124 connected to a fixed brace 122 is positioned at a first limit 125 of the cam 123.

[0108] In Figure 8b, traveler 121 is centered to the left of the position in Figure 8a. From the position shown in Figure 8a, cam 123 has moved relative to follower 124 so that follower 124 is at the first inflection point of the cam slot. Fixed brace 122 has not moved its position relative to the position in Figure 8a.

[0109] In Figure 8c, traveler 122 is positioned horizontally to the left. Cam 123 is moving relative to follower 124 so that follower 124 must move vertically up the incline to reach second limit 126. Because follower 124 is fixed to fixed brace 122, which is fixed horizontally, it necessarily moves vertically.

[0110] 8a and 8b, the fixed brace 122 is in a lowered position relative to the traveler 121, and in FIG. 8c, the fixed brace 122 is in a raised position relative to the traveler 121.

[0111] It will be appreciated that if a pair of wheels is fixedly mounted to fixed braces 122, the cam mechanism 120 may be used to raise and lower the wheels as needed by applying a horizontal force to the traveler 121. The position of cam 120 shown in Figure 8b can be used as a "parked" position, where the wheels are ready to be moved to an engaged position (Figure 8a) or a disengaged position (Figure 8c).

[0112] It will be appreciated that the cam profile may be designed to provide any desired horizontal to vertical movement profile.

[0113] 9 illustrates another cam mechanism 130 employing a double-cam configuration. A first cam 133a and a second cam 133b are arranged adjacent to each other in the horizontal direction. The first cam profile and the second cam profile 133b are substantially identical. Similarly, a pair of followers 124a and 124b are arranged to engage with the respective cams 133a and 133b.

[0114] This configuration further differs from the configuration shown in Figures 8a to 8c in that the first cam 133a and second cam 133b are disposed on fixed braces 132a, 132b and the first follower 134a and second follower 134b are attached to the traveler 131, i.e., the traveler is inverted. The fixed brace portions 132a and 132b are joined by a pair of bars.

[0115] Operation of cam mechanism 130 is similar to that of cam mechanism 120. When a horizontal force is applied to traveler 131, followers 134a and 134b move in unison along first cam path 133a and second cam path 133b between first limits 135a, 135b and second limits 136a, 136b, respectively. Assuming fixed braces 132a, 132b are constrained to move only vertically, horizontal movement of traveler 131 raises and lowers fixed braces 132a, 132b, similar to the function of cam mechanism 120. Figures 10a-10c illustrate inverted double cam mechanism 130 in positions corresponding to the positions of single cam mechanism 120 shown in Figures 8a-8c, respectively.

[0116] FIG. 11 illustrates another inverted cam mechanism 140 employing a triple cam configuration. A first cam 143a and a first follower 144a, a second cam 143b and a second follower 144b, and a third cam 143c and a third follower 144c are horizontally adjacent to each other. Fixed brace portions 142a, 142b, and 142c are joined. Otherwise, the configuration of the triple cam mechanism 140 is similar to that of the double cam mechanism 130. Operation of the triple cam mechanism 140 is similar to that of the cam mechanisms 120 and 130.

[0117] As noted above, a cam profile may be defined on a traveler with a follower attached to a fixed brace (FIGS. 7 and 8), or a follower may be attached to a traveler with a cam profile defined on a fixed brace (FIGS. 9-11). Such an inverted or "mirrored" arrangement is shown in FIGS. 12a and 12b, where FIG. 12a is similar to FIGS. 9-11 and FIG. 12b is similar to FIGS. 7 and 8. For simplicity, a single cam mechanism is shown, and it will be understood that this inversion or mirroring can apply to cam mechanisms having any number of similar cams (double, triple, etc.).

[0118] In Figure 12, cam mechanisms 150a, 150b are configured with travelers 151a, 151b, fixed braces 152a, 152b, cams 153a, 153b, and followers 154a, 154b, respectively. In Figure 12a, follower 154a is attached to traveler 151a and cam 153a is defined on fixed brace 152a, while in Figure 12b, the opposite is true. It will be appreciated that cam path 153a is a mirror reflection around an imaginary horizontal line compared to cam path 153b to achieve the same vertical movement of fixed braces 152a, 152b for a given horizontal input on the respective travelers 151a, 151b.

[0119] An alternative cam mechanism 160 arrangement is shown in Figures 13a-13c. Unlike the previously described cam mechanisms 120, 130, 140, and 150, the cam profile is defined by the lower edge 163 of a traveler 161 rather than by a slot. The traveler 161 can move horizontally between the corner blocks. The follower 164 is fixed in place on a fixed brace frame 162, which is slidably mounted on a vertical corner pole and constrained to vertical movement only. Otherwise, the cam mechanism 160 operates similarly to the previously described configurations.

[0120] 13, it will be appreciated that when follower 164 is in a position such that fixed brace 162 is raised relative to traveler 161, fixed brace 162 will tend to drop due to gravity, thereby disengaging the follower from cam surface or lower edge 163. This tendency is counteracted by spring 167 which is biased to pull fixed brace 162 toward traveler 161.

[0121] It will be appreciated that a spring may be used in any of the above configurations to bias the cam mechanism to a particular configuration.

[0122] Again, as with the examples discussed above, particularly in relation to Figures 12a and 12b, it will be appreciated that the surface or edge cam configuration may be configured in a mirror image or inverted fashion relative to the configuration shown in Figure 13, as shown in Figure 14, with the cam mechanism 170 comprising a traveler 171, a fixed brace 172, a cam surface 173 and a follower 174, and further comprising a spring 177.

[0123] It will be understood that the cam mechanism described herein may be used as part of a redirection assembly for any of the load handling devices described in connection with Figures 1 to 6, or any load handling device intended to operate with movement in two directions on a Cartesian coordinate system.

[0124] The cam mechanisms described herein may be suitable for placement on each face of a load handling device as part of a diverter assembly. In some load handling devices, it may be necessary to have a diverter assembly on only one pair of opposing faces, i.e., the x-direction face or the y-direction face.

[0125] As discussed above in connection with FIG. 6, in some load handling devices, the turning assembly includes mechanisms on each side of the load handling device for raising and lowering pairs of wheels for x-direction movement, and similarly (sometimes simultaneously) for lowering and raising pairs of wheels for y-direction movement, respectively.

[0126] The cam mechanisms on each face of the load handling device may be linked by belts, chains, or other mechanical means to coordinate the movement of the wheel pairs. It will be appreciated that vertically mirrored or horizontally mirrored cam profiles may be required on each individual face to ensure precise coordinated movement of the wheel pairs.

[0127] 17a-b illustrate cam mechanisms 190a, 190b with anti-rotation legs, where FIG. 17a has the cam attached to the traveler and FIG. 17b is an inverted version of the mechanism illustrated in FIG. 17a with the cam attached to the fixed brace.

[0128] In each of Figures 17a and 17b, the cam mechanism includes an engagement means between the traveler and the fixed brace. As shown, the traveler has a protruding anti-rotation leg 191, and the fixed brace has a corresponding protruding base 192. As shown in Figures 17a and 17b, the cam mechanism 190a, 190b is in an engaged or driven position, in which the wheel is in contact with the surface. The leg 191 and base 192 are in contact, such that the base 192 supports the anti-rotation leg 191.

[0129] Figures 18a-18f illustrate the cam mechanism 190a, 190b of Figure 17 in the raised position (Figures 18a, 18d), the parked position (Figures 18b, 18e), and the drive position (Figures 18c, 18f). As can be seen, the legs 191 only engage the base 192 when in the drive position.

[0130] Figures 15 and 16 illustrate possible wheel mount arrangements incorporating cam mechanism redirection assembly components as described herein. The wheel mount arrangements are suitable for any of the disclosed cam mechanisms. Figures 15a and 15b illustrate a side view of the cam and wheel mount arrangement, and Figure 16 illustrates a front view of the cam and wheel mount arrangement. It can be seen from Figures 15 and 16 that the cam mechanism occupies substantially a single vertical plane and is compact.

[0131] For each side of the load handling device, a double cam mechanism 180 is mounted between the middle harrow of the load handling device and the wheel chassis. The cam mechanism 180 may be any of the cam mechanisms described herein and is not necessarily limited to the double cam mechanism as shown.

[0132] The traveler 181 of each cam mechanism 180 is attached to a rod 182 that defines the intermediate harrow of the load handling device. It will be understood that the traveler 181 is mounted so as to freely slide or glide on the intermediate harrow between the corner blocks. Substantially vertically below the traveler 181 is a block 183 having a slot that defines the cam profile. The block 183 is assembled into two halves between which a roller (or follower) 184 can be clamped. The block 183 is directly connected to a wheel mount block 185.

[0133] Figure 15a shows a side profile of the x-direction wheel mount and Figure 15b shows a side profile of the y-direction wheel mount. It will be appreciated that the wheel mount blocks may interlock around the vertical rods 186 of the framework of the load handling device.

[0134] Figures 19a through 19f illustrate the load handling device being driven in the direction of the arrow, to the right as shown. The cam mechanism 190a illustrated in Figures 19a through 19c is similar to the cam mechanism shown in Figures 17a and 18a through 18c. The cam mechanism illustrated in Figures d through f lacks the feet and corresponding bases. In each figure, the cam mechanism is in a driven position with the wheels engaging a surface.

[0135] As shown in Figure 19d, the load handling device is moving to the right and accelerating, which would tend to tilt backwards or to the left, making the load handling device unstable.

[0136] As shown in Figure 19e, the load handling device is moving to the right at a constant speed. After moving at a constant speed, there should be no tilt, even without the legs. However, because the load handling device tends to tilt backward when accelerated, as the load handling device returns to a constant speed, there may be a sway or oscillation between a slight backward and a slight forward tilt before the load handling device stabilizes.

[0137] As shown in Figure 19f, the load handling device is moving to the right and is being decelerated, in which case the load handling device will tend to tip forward, making the load handling device unstable.

[0138] In contrast, when a load handling device having a cam mechanism such as 190a is actuated under the same conditions, legs 191 engage base 192. The support provided to legs 191 by base 192 helps to stabilize the load handling device by making the mechanism more rigid and reducing the amount of tilt.

[0139] As shown in Figure 19a, the load handling device is moving to the right and accelerating, as shown in Figure 19b, the load handling device is moving to the right at a constant speed, and as shown in Figure 19c, the load handling device is moving to the right and decelerating, in each case the load handling device remains substantially horizontal as the engagement of the legs with the base makes the structure more rigid.

[0140] It will be appreciated that where the load handling device is carrying a variety of loads, it is advantageous for the load handling device to remain substantially horizontal during movement in order to increase the accuracy of control.

[0141] It will be appreciated that if the cams are located on the wheel mounts, the symmetry may be selected to be symmetrical when the wheels are fully down to provide the best stability when the load handling device is being driven. As a result, lifting may not be perfectly symmetrical for lifting the front and rear wheels. It will be appreciated that the symmetry point may be selected to optimize other aspects of the assembly.

[0142] It will be appreciated that the wheel mount subassembly will tilt when lifted (with a single cam), causing one wheel to lift before the other, potentially causing errors, potentially causing uneven wear on other components (e.g., the plain bearings between the traveler and intermediate harrow, or the plain bearings between the vertical mounting rods and corner blocks), and potentially causing increased forces on certain areas of the load handling device during turning operations. Thus, some of the benefits of a single cam mechanism may be realized by the support or engagement means.

[0143] If the cam is located on the traveler, the wheel may be lifted symmetrically because the roller is stationary relative to the driven wheel, regardless of whether the device has a single cam or dual cams. However, dual cams on the traveler may not be feasible due to space constraints and other component considerations.

[0144] Although a load handling device is described herein that operates on a grid-based multi-level storage system having a grid disposed above the storage stacks, it will be understood that the diverting assembly and / or cam mechanism may be applied to other autonomous or semi-autonomous devices. For example, the diverting assembly or cam mechanism may be applied to a Kiva (RTM) or similar autonomous mobile robot (AMR) type bot, which has a lower overall height, to position itself beneath a stack of containers or totes and enable the stack to be lifted from below. It will be understood that the assembly described herein is suitable for this type of bot due to the relatively small vertical space required for assembly.

[0145] Although the foregoing specification has attempted to draw attention to those features of the invention which are believed to be particularly important, it is to be understood that applicants claim protection for any patentable feature or combination of features referred to in this specification and / or shown in the drawings, whether or not specifically emphasized.

[0146] It should be appreciated that a cam mechanism can be designed for a particular application using various combinations of the devices and configurations described above. It should be appreciated that all of the features described above may be used together in a single system. In other embodiments of the invention, some of the features may be omitted. The features may be used in any compatible configuration. Many variations and modifications not expressly described above are possible without departing from the scope of the invention as defined in the appended claims. The inventions described in the original claims of this application are set forth below. [1] A cargo handling device for lifting and moving storage containers stacked on a framework structure of a grid-based storage system, comprising: a first set of parallel rails or tracks; and a second set of parallel rails or tracks extending substantially perpendicular to the first set of rails or tracks in a substantially horizontal plane to form a grid pattern having a plurality of grid spaces, wherein the grid is supported by the set of upright members such that the containers are stacked vertically between the upright members through the plurality of grid spaces and guided by the upright members to form a plurality of vertical storage locations below the grid; the load handling device comprises a framework including a frame defining a volume having an upper portion, a lower portion, and an intermediate harrow between the upper portion and the lower portion; a first set of wheels disposed on the lower portion of the framework and a second set of wheels disposed on the lower portion of the framework, the first set of wheels positioned to engage the first set of parallel tracks and the second set of wheels positioned to engage the second set of parallel tracks; a diverting assembly positioned to raise or lower the first set of wheels relative to the framework and / or raise or lower the second set of wheels relative to the framework to engage and disengage the first and second sets of wheels with the parallel tracks, the diverting assembly being located between the intermediate harrow and the first set of wheels and / or the second set of wheels, wherein the diverting assembly comprises a cam mechanism. [2] The load handling device according to [1], wherein the cam mechanism is fixed directly to a wheel chassis for mounting the first set of wheels or the second set of wheels, respectively. [3] A load handling device as described in [1] or [2], wherein the fixed brace is constrained by one or more attachments on the framework to move only vertically. [4] A load handling device as described in any one of [1] to [3], wherein the turning assembly is configured to raise or lower the first set of wheels relative to the framework and simultaneously raise or lower the second set of wheels relative to the framework. [5] A load handling device as described in any one of [1] to [4], wherein the cam mechanism comprises an engagement means between a traveler and a fixed brace. [6] A load handling device as described in any one of [1] to [5], wherein the cam mechanism has a single cam configuration, or the cam mechanism has a double cam configuration, or the cam mechanism has a triple cam configuration. [7] A load handling device as described in any one of [1] to [6], wherein the cam mechanism is arranged in a single vertical plane between the intermediate harrow and each pair of wheels. [8] A load handling device as described in any one of [1] to [7], wherein the diverting assembly is operated by a single motor, or the diverting assembly is operated by two or more motors. [9] A load handling device as described in any one of [1] to [8], wherein each pair of the first set of wheels and the second set of wheels is driven by a drive belt, and the cam mechanism is positioned within an area defined by the path of the drive belt.

[10] A load handling device as described in any one of [1] to [9], further comprising sensing means for determining engagement of the first set of wheels and the second set of wheels with parallel tracks.

[11] A load handling device as described in any one of [1] to

[10] , further comprising sensing means for determining a malfunction or failure of the turning assembly.

[12] A load handling device as described in any one of [1] to

[11] , wherein at least a portion of the cam mechanism is 3D printed and / or at least a portion of the cam mechanism is substantially topologically optimized.

[13] A load handling device as described in any one of [1] to

[12] , further comprising a lifting device supported by the upper portion of the framework for lifting a container into the volume.

[14] A method of modifying engagement of a set of wheels with a track of a load handling device according to any one of [1] to

[13] , the load handling device operating on a grid framework (14) structure comprising a track, the method comprising: applying a force to a traveler of the diverting assembly in a first direction F1 to move a cam mechanism to a first limit; or applying a force to the traveler of the redirection assembly in a second direction F2 to move the cam mechanism to a second limit.

[15] A kit of parts for modular assembly of a load handling device according to any one of [1] to

[13] , said kit comprising: a framework, a first set of wheels, and a second set of wheels, wherein the framework may be attached to the first set of wheels and the second set of wheels; and at least one redirection assembly comprising at least one cam mechanism, each cam mechanism having a traveler, a fixed brace, a follower, and a cam path.

[16] The kit of parts according to

[15] , further comprising at least two cam mechanisms and a transport belt.

[17] The kit of parts according to

[15] or

[16] , further comprising at least one direction-changing motor.

[18] A kit of parts according to any one of

[15] to

[17] , wherein at least one part is 3D printed.

[19] The kit of parts of any one of

[15] to

[18] , further comprising at least one of a set of wheels, a drive assembly, a gripper assembly, a lifting assembly, a communication system, and / or sensor means.

Claims

1. A load handling device for lifting and moving storage containers stacked on a framework structure of a grid-based storage system, comprising: a first set of parallel rails or tracks; and a second set of parallel rails or tracks extending substantially perpendicular to the first set of rails or tracks in a substantially horizontal plane to form a grid pattern having a plurality of grid spaces, wherein the grid is supported by the set of upright members such that the containers are stacked vertically between and guided by the upright members through the plurality of grid spaces to form a plurality of vertical storage locations below the grid; the load handling device comprises a framework including a frame defining a volume having an upper portion, a lower portion, and an intermediate harrow between the upper portion and the lower portion; a first set of wheels disposed on the lower portion of the framework and a second set of wheels disposed on the lower portion of the framework, the first set of wheels positioned to engage the first set of parallel tracks and the second set of wheels positioned to engage the second set of parallel tracks; a diverting assembly arranged to raise or lower the first set of wheels relative to the framework and / or raise or lower the second set of wheels relative to the framework to engage and disengage the first and second sets of wheels with the parallel tracks, the diverting assembly being located between the intermediate harrow and the first set of wheels and / or the second set of wheels, wherein the diverting assembly comprises a cam mechanism.

2. 2. The load handling device of claim 1, wherein the cam mechanism is fixed directly to a wheel chassis for mounting the first set of wheels or the second set of wheels, respectively.

3. 10. The load handling device of claim 1, wherein the fixed brace is constrained by one or more fixtures on the framework to move only vertically.

4. 2. The load handling device of claim 1, wherein the diverting assembly is configured to raise or lower the first set of wheels relative to the framework and simultaneously raise or lower the second set of wheels relative to the framework.

5. 2. The load handling device of claim 1, wherein the cam mechanism comprises an engagement means between a traveler and a fixed brace.

6. 10. The load handling device of claim 1, wherein the cam mechanism comprises a single cam configuration, or the cam mechanism comprises a double cam configuration, or the cam mechanism comprises a triple cam configuration.

7. 2. The load handling device of claim 1, wherein the cam mechanisms are disposed in a single vertical plane between the intermediate harrow and each pair of wheels.

8. 10. The load handling device of claim 1, wherein the diverting assembly is operated by a single motor, or the diverting assembly is operated by two or more motors.

9. 2. The load handling device of claim 1, wherein each pair of the first set of wheels and the second set of wheels is driven by a drive belt, and the cam mechanism is positioned within an area defined by a path of the drive belt.

10. 2. The load handling device of claim 1, further comprising sensing means for determining engagement of said first set of wheels and said second set of wheels with parallel tracks.

11. 10. A load handling device according to claim 1, further comprising sensing means for determining a malfunction or failure of the turning assembly.

12. 10. The load handling device of claim 1, wherein at least a portion of the cam mechanism is 3D printed and / or at least a portion of the cam mechanism is substantially topologically optimized.

13. 10. The load handling device of claim 1, further comprising a lift device supported by the upper portion of the framework for lifting containers into the volume.

14. 14. A method of altering engagement of a set of wheels with a track of a load handling device according to any one of claims 1 to 13, said load handling device operating on a grid framework (14) structure comprising a track, said method comprising: applying a force to a traveler of the diverting assembly in a first direction F1 to move a cam mechanism to a first limit; or applying a force to the traveler of the redirection assembly in a second direction F2 to move the cam mechanism to a second limit.

15. 14. A kit of parts for modular assembly of a load handling device according to any one of claims 1 to 13, said kit comprising: a framework, a first set of wheels, and a second set of wheels, wherein the framework may be attached to the first set of wheels and the second set of wheels; and at least one redirection assembly comprising at least one cam mechanism, each cam mechanism having a traveler, a fixed brace, a follower, and a cam path.

16. The kit of parts of claim 15 further comprising at least two cam mechanisms and a transport belt.

17. The kit of parts of claim 15 further comprising at least one direction-changing motor.

18. 16. The kit of parts of claim 15, wherein at least one part is 3D printed.

19. 16. The kit of parts of claim 15, further comprising at least one of a set of wheels, a drive assembly, a gripper assembly, a lifting assembly, a communication system, and / or sensor means.

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