Lifting Assembly

Abstract

Lifting Assembly A container lifting assembly for raising and / or lowering containers stacked in a lattice storage structure, the lifting assembly comprising a gripping device configured to releasably grip a container, and a lifting mechanism configured to raise and lower the gripping device, the lifting mechanism comprising a gear mechanism configured to wind and / or unwind at least one tether, and a motor configured to actuate the gear mechanism to wind and / or unwind the at least one tether, wherein the at least one tether is connected to the gripping device such that winding and unwinding of the at least one tether is configured to raise and lower the gripping device.

Description

[Technical field]

[0001] The present invention relates to the field of lifting assemblies, and in particular to lifting assemblies for load handling devices for lifting and moving storage containers. [Background technology]

[0002] Several commercial and industrial activities require systems that allow the storage and retrieval of a large number of different products. WO2015 / 185628A describes a storage and fulfillment system in which a stack of storage containers is arranged within a lattice framework structure. The containers are accessed from above by a load handling device that operates on rails or tracks located at the top of the lattice storage structure.

[0003] A given load handling device lifts a target container from the top of a stack, which typically contains an inventory item needed to fulfill a customer order. The load handling device also lowers the target container back to the top of the stack, to the top of another stack, or to another location, as needed. The load handling device typically includes a lifting assembly for lifting the container from a first location and lowering the container to a second location. The load handling device must reliably raise and lower each container from its required location.

[0004] It is against this background that the present invention was conceived. Summary of the Invention

[0005] In a first aspect, there is provided a container lifting assembly for raising and / or lowering containers stacked in a grid storage structure, the lifting assembly comprising: a gripping device configured to releasably grip the container; a lifting mechanism for lifting and lowering the gripping device, The lifting mechanism is a gear mechanism configured to reel in and / or unreel at least one tether; a motor configured to operate a gear mechanism to reel in and / or unreel at least one tether; At least one tether is connected to the gripping device such that winding and unwinding of the at least one tether is configured to raise and lower the gripping device.

[0006] The gear mechanism may comprise a spool (e.g., at least one spool, e.g., a spool for each tether). The tether (e.g., at least one tether) may extend from the spool before extending to and connecting to the gripping device. The gear mechanism may be configured to wind and / or unwind the tether around the spool. The lifting and lowering mechanism may comprise a pair of tethers (e.g., at least one pair of tethers, e.g., two pairs of tethers) and a spool for each pair of tethers. The gear mechanism may be configured to wind and / or unwind the pair of tethers around the spool. The lifting mechanism may comprise at least one pulley (e.g., at least one pulley for each tether). The tether may extend from the spool to the pulley before extending to and connecting to the gripping device. If the raising and lowering mechanism includes a spool for each pair of tethers, each tether of the pair of tethers may extend in opposite directions from the spool to a pulley before extending and connecting to the gripping device. The raising and lowering mechanism may include a pulley for each tether.

[0007] The raising and lowering mechanism may comprise at least one tether (e.g., one, two, three, four, etc. tethers). The or each tether may extend from the gear mechanism to a corner of the gripping device.

[0008] The lifting mechanism may include a horizontally extending lifting shaft. The lifting mechanism may include two spools, e.g., a first spool at a first end of the lifting shaft and / or a second spool at a second end of the lifting shaft, the second end being opposite the first end. The lifting mechanism may include two tethers at the first end of the lifting shaft configured to be wound onto and / or unwound from the first spool. The lifting mechanism may include two tethers at the second end of the lifting shaft configured to be wound onto and / or unwound from the second spool.

[0009] The lifting mechanism may include four spools, e.g., two spools at the first end of the lifting shaft and / or two spools at the second end of the lifting shaft. The lifting mechanism may include two tethers at the first end of the lifting shaft, each tether configured to be wound onto and unwound from a respective spool at the first end of the lifting shaft (i.e., each tether at the first end of the lifting shaft extends from its own spool). The lifting mechanism may include two tethers at the second end of the lifting shaft, each tether configured to be wound onto and unwound from a respective spool at the second end of the lifting shaft (i.e., each tether at the second end of the lifting shaft extends from its own spool).

[0010] At least one spool of the lifting mechanism may include a slip clutch (i.e., the spool may be attached to the lifting shaft via a slip clutch). Each spool of the lifting mechanism may be attached to the lifting shaft via a respective slip clutch. At least one pulley may include a hard stop (e.g., a mechanical stop) against which the gripping device abuts when the gripping device reaches its fully lifted position (i.e., when the gripping device is fully lifted by the lifting mechanism). Each pulley of the lifting mechanism may include a hard stop (e.g., a mechanical stop) against which each corner of the gripping device abuts when it reaches its fully lifted position as each tether is wound to raise the gripping device. The motor may be configured to rotate the lifting shaft to wind or unwind the tether, thereby raising or lowering the gripping device. During the raising and / or lowering of the gripping device, the gripping device may be uneven, i.e., one side of the gripping device may be higher than the other side or one or more corners of the gripping device may be higher than the remaining corners of the gripping device. When the gripping device is raised to its fully raised position, the higher gripping device sides or higher corners may reach their fully raised position and abut the hard stop before the uneven lower side or corners of the gripping device reach the hard stop.

[0011] To level an uneven gripping device, the motor may over-rotate the lifting shaft to lift any uneven lower side or lower corner of the gripping device. During this over-driving or over-rotating of the motor, the slip clutches of the sides or corners that are already in a fully lifted position can slip and prevent further rotation of those spools, thereby keeping the sides or corners that are already in a fully lifted position against the hard stop. The motor may over-lift the gripping device against the hard stop each time the gripping device is raised. The slip clutches can allow the motor to over-rotate the lifting shaft and lift any uneven lower side or corner of the gripping device while still maintaining any side or corner of the gripping device already in a fully lifted position against the hard stop. In this way, the lifting assembly can calibrate and level the gripping device each time the gripping device is raised.

[0012] The slip clutch includes a shaft or hollow bore located in the center of the spool and attached to the lifting shaft, thereby mounting the spool to the lifting shaft. The slip clutch may be a spring clutch or an electromagnetic clutch (e.g., a permanent magnet clutch or a hysteresis / magnetic particle clutch). The slip clutch may be a fixed torque or an adjustable torque clutch.

[0013] A gear mechanism may be provided on the gripping device. When the gear mechanism winds up the tether (e.g., at least one tether), the gripping device can rise towards the top of the lifting assembly, i.e., as opposed to being pulled to the top of the lifting assembly (e.g., in embodiments where a gear mechanism is not provided on the gripping device, e.g., above the gripping device, and / or in the load handling device). A motor may be provided on the gripping device. Thus, the gripping device may be self-powered, i.e., the gripping device may use power from a motor on the gripping device (i.e., may not require power from the load handling device).

[0014] The gear mechanism may comprise a planetary gear set or a worm gear, or any other gear mechanism suitable for winding and / or unwinding the tether.

[0015] The tether may be in the form of a cable, rope, tape, or any other form of tether having the necessary physical properties to lift a container. The tether may be formed from or include a polyester material (e.g., a woven polyester material). In particular, the tether may include a woven polyester tape or belt, such as a seat belt (i.e., a seat belt may be used as a tether). The tether may include a Dyneema tape. The tether may include a polyester material (e.g., a woven polyester) combined with a Dyneema tape. The tether may include a cotton material. The tether may include a webbing material, such as webbed polyester, nylon, cotton. The tether may include a conductive material, for example, the tether may include a woven material or a woven polyester material having conductive elements or wiring (e.g., copper) woven into the weave or fabric of the tether. The tether may include a woven belt (e.g., a seat belt) having conductive elements or wiring woven into the belt. The tether may comprise conductive elements or wiring (e.g. copper) woven into the weave or fabric of the tether to provide power and / or communication (i.e. electrical communication) to the gripping device. In another aspect, there is provided a container lifting assembly according to the first aspect, wherein the lifting mechanism comprises: a horizontally extending lifting shaft, a first spool, a second spool, a third spool, and a fourth spool, wherein the first and second spools are disposed at or near a first end of the horizontally extending lifting shaft, and the third and fourth spools are disposed at or near a second end opposite the first end of the horizontally extending lifting shaft; The tether includes a first tether, a second tether, a third tether, and a fourth tether configured to be wound and unwound from first, second, third, and fourth spools, respectively, where the first and second spools are configured to rotate in opposite directions to the third and fourth spools to wind and unwind the first, second, third, and fourth tethers.

[0016] The first and second spools may be on a first shaft and the third and fourth spools may be on a second shaft, where the gear mechanism may include first and second pulleys on the first and second shafts, respectively, the first and second pulleys being driven in opposite directions via a timing belt.

[0017] The gear mechanism may further include third and fourth pulleys disposed about either the first or second pulley to effect opposite rotation of the first and second pulleys via the timing belt.

[0018] Any one of the first, second, third and fourth pulleys may be directly driven by the motor.

[0019] The gear mechanism may include first and second worm gears on a shaft driven by the motor, where the worm gears are configured to effect rotation of the first and second spools in opposite directions to the third and fourth spools.

[0020] The first and second spools may be on a first shaft and the third and fourth spools may be on a second shaft, wherein the gear mechanism may further comprise first and second gears on the first and second shafts, respectively, the first and second gears being driven via first and second worm gears, respectively.

[0021] In another aspect there is provided a container lifting assembly according to the first aspect, the lifting mechanism comprising: a horizontally extending lifting shaft; a first spool, a second spool, a third spool, and a fourth spool, wherein the first and second spools are disposed adjacent to a first side or proximate a central axis of the horizontally extending lifting shaft, and the third and fourth spools are disposed adjacent to a second side or proximate a central axis, wherein the first side is opposite the second side; The tether includes a first tether, a second tether, a third tether, and a fourth tether configured to be wound and unwound from first, second, third, and fourth spools, respectively, where the first and second spools are configured to rotate in opposite directions to the third and fourth spools to wind and unwind the first, second, third, and fourth tethers.

[0022] The first and second spools may be on a first shaft and the third and fourth spools may be on a second shaft, the first and second shafts being parallel to the central axis.

[0023] The gear mechanism may comprise a first gear and a second gear on the first shaft and the second shaft, respectively, where the first gear and the second gear mesh such that a motor driving either the first shaft or the second shaft rotates the other of the first shaft or the second shaft.

[0024] Each tether may be coupled to a respective pulley located at or near a respective corner of the lifting assembly.

[0025] In any of the above embodiments, the first, second, third, and fourth tethers are configured such that the point at which each tether is wound onto or unwound from a respective spool or pulley is at or near a respective corner of the lifting mechanism.

[0026] Each tether can be connected to the gripping device at or near a respective corner of the gripping device.

[0027] In any of the above embodiments, at least one spool includes at least one groove along its circumference into which the wire tether is configured to wind.

[0028] In another aspect, a load handling device is provided for lifting and moving containers stacked in a stack of a grid storage structure comprising a plurality of tracks arranged in a grid pattern above the stack of containers, the load handling device comprising: a body housing a drive mechanism operatively arranged to move the load handling device over the grid; and a container lifting assembly as described above configured to raise and lower the gripping device relative to the body for raising and lowering the containers stacked in the stack.

[0029] The lifting assembly may be positioned within the body of the load handling device. The lifting assembly is capable of lifting the container into the body (e.g., into a cavity of the load handling device).

[0030] The tether may include conductive elements or wiring (e.g., copper) woven into the weave or fabric of the tether to provide power and / or communication (i.e., electrical communication) between the load handling device (e.g., a power source or communication source provided on the body of the load handling device) and the gripping device.

[0031] In another aspect, a load handling device is provided for lifting and moving containers stacked in a grid storage structure, the load handling device comprising: a first set of parallel tracks and a second set of parallel tracks extending substantially perpendicular to the first set of tracks in a substantially horizontal plane to form a grid pattern comprising a plurality of grid spaces, wherein the grid is supported by the set of uprights to form a plurality of vertical storage locations beneath the grid such that containers are stacked between and guided by the uprights vertically through the plurality of grid spaces; a body mounted on a first set of wheels arranged to engage a first set of parallel tracks and a second set of wheels arranged to engage a second set of parallel tracks; the body housing a drive mechanism configured to drive a load handling device on the grid; and a container lifting assembly as described above configured to raise and lower the gripping device relative to the body for raising and lowering the containers stacked in the stack.

[0032] In another aspect, there is provided a method of raising and / or lowering a container from a stack of containers, the method comprising a load handling device as described above, the method comprising: activating a gear mechanism to rewind at least one tether and lower the gripping device relative to the body; activating a gripping device to grip the container; and operating a gear mechanism to wind the tether and raise the gripping device relative to the body.

[0033] The method may comprise the step of raising the gripping device relative to the body and lifting the container into a cavity of the load handling device.

[0034] In one embodiment, A load handling device as defined above; a storage structure for receiving containers stacked in a stack, the storage structure including a first set of tracks extending in a first direction and a second set of tracks extending in a second direction transverse to the first direction, a load handling device configured to travel on the first and second sets of tracks; and a control utility configured to control the load handling devices to lift containers from the stack below the grate and / or lower containers into the grate.

[0035] Aspects and embodiments of the present invention will now be described with reference to the accompanying drawings. [Brief description of the drawings]

[0036] [Figure 1] FIG. 1 is a schematic perspective view of a lattice storage structure and a container. [Diagram 2] FIG. 2 is a schematic top view of the upper track of the storage structure of FIG. [Diagram 3] FIG. 3 shows a load handling device on top of the storage structure of FIG. [Figure 4] FIG. 4 is a schematic perspective view of a load handling device having a lifting assembly in a lowered configuration. [Diagram 5] FIG. 5 shows a schematic cut-away view of the load handling device of FIG. 4 with the lifting assembly in a raised and lowered configuration. [Figure 6A] FIG. 6A is a perspective view of a load handling device having an embodiment of a lifting assembly being lowered onto a container. [Figure 6B] FIG. 6B is a perspective view of a load handling device having an embodiment of a lifting assembly being lowered onto a container. [Figure 6C] FIG. 6C is a perspective view of a load handling device having an embodiment of a lifting assembly being lowered onto a container. [Figure 7] FIG. 7 is a front view of an embodiment of a lifting assembly. [Figure 8] FIG. 8 is a top view of the lifting assembly of FIG. [Figure 9] FIG. 9 is a top view of the lifting assembly of FIG. [Figure 10] FIG. 10 is a perspective view of another embodiment of a lifting assembly. [Figure 11A] 11A is a perspective view of one of the spools of the lifting assembly of FIG. 10. FIG. [Figure 11B] 11B is a side view of one of the spools of the lifting assembly of FIG. [Figure 11C]11C is a front view of one of the spools of the lifting assembly of FIG. 10. FIG. [Figure 12] FIG. 12 is a perspective view of another embodiment of a lifting assembly. [Figure 13] FIG. 13 is a perspective view of a lifting and lowering mechanism of another embodiment of the lifting assembly. [Figure 14A] FIG. 14A is a perspective view of another embodiment of a lifting assembly. [Figure 14B] FIG. 14B is a perspective view of another embodiment of a lifting assembly. [Figure 15] FIG. 15 is a perspective view of another embodiment of a lifting assembly. [Figure 16] FIG. 16 is a perspective view of another embodiment of a lifting assembly. [Figure 17] FIG. 17 is a perspective view of another embodiment of a lifting assembly. [Figure 18] FIG. 18 is a perspective view of another embodiment of a lifting assembly. [Figure 19] FIG. 19 is a perspective view of another embodiment of a lifting assembly. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] 1 illustrates a storage structure 1 comprising upright members 3 and horizontal members 5, 7 supported by upright members 3. The horizontal members 5 extend parallel to each other and to an illustrated x-axis. The horizontal members 7 extend parallel to each other and to an illustrated y-axis and transverse to the horizontal members 5. The upright members 3 extend parallel to each other and to an illustrated z-axis and transverse to the horizontal members 5, 7. The horizontal members 5, 7 form a grid pattern defining a plurality of grid cells. In the illustrated example, the storage containers 9 are arranged in stacks 11 below the grid cells defined by the grid pattern, one stack 11 of containers 9 per grid cell.

[0038] FIG. 2 shows an enlarged plan view of a section of a track structure 13 forming part of the storage structure 1 illustrated in FIG. 1 and located on top of the horizontal members 5, 7 of the storage structure 1 illustrated in FIG. The track structure 13 may be provided by the horizontal members 5, 7 themselves (e.g. formed in or on a surface of the horizontal members 5, 7) or by one or more additional components attached to the top of the horizontal members 5, 7. The track structure 13 shown comprises x-direction tracks 17 and y-direction tracks 19, i.e. a first set 17 of tracks extending in the x-direction and a second set 19 of tracks extending in the y-direction transverse to the tracks 17 in the first set 17 of tracks. The tracks 17, 19 define openings 15 in the center of the lattice cells. The openings 15 are sized to allow containers 9 located below the lattice cells to be lifted and lowered through the openings 15. The x-direction tracks 17 are provided in pairs separated by a channel 21 and the y-direction tracks 19 are provided in pairs separated by a channel 23. Other configurations of the track structure are possible.

[0039] Figure 3 shows multiple load handling devices 31 moving on top of the storage structure 1 illustrated in Figure 1. The load handling devices 31, which may also be referred to as robots 31 or bots 31, are provided with a set of wheels for engaging with corresponding x-direction tracks 17 or y-direction tracks 19 to enable the bots 31 to move across the track structure 13 and reach a particular grid cell. The illustrated pair of tracks 17, 19 separated by channels 21, 23 allows the bots 31 to occupy adjacent grid cells (or pass each other) without colliding with each other.

[0040] 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 throughout 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.

[0041] The illustrated bot 31 includes a first set of wheels 35 and a second set of wheels 37 that are attached to the body 33 of the bot 31 and allow the bot 31 to move along the tracks 17 and 19 in the x and y directions, respectively. In particular, two wheels 35 are provided on the short side of the bot 31 visible in FIG. 4 and two more wheels 35 are provided on the opposite short side of the bot 31 (not visible in FIG. 4). The wheels 35 engage with the tracks 17 and are rotatably attached to the body 33 of the bot 31 to allow the bot 31 to move along the tracks 17. Similarly, two wheels 37 are provided on the long side of the bot 31 visible in FIG. 4 and two more wheels 37 are provided on the opposite long side of the bot 31 (not visible in FIG. 4). The wheels 37 engage with the tracks 19 and are rotatably attached to the body 33 of the bot 31 to allow the bot 31 to move along the tracks 19.

[0042] The bot 31 also includes a lifting assembly 102 comprising a lifting mechanism 39 configured to raise and lower the container 9. The illustrated lifting mechanism 39 comprises four tethers 41 connected at their lower ends to a gripping device 100. The tethers 41 may be in the form of cables, ropes, tapes, or any other form of tethers having the necessary physical properties to lift the container 9. The gripping device 100 includes at least one gripper configured to engage features of the container 9. For example, the containers 9 may be provided with one or more apertures on their upper side with which the gripper can engage. Alternatively or additionally, the gripping means may be configured to hook under a rim or lip of the container 9 and / or clamp or grip the container 9. The tethers 41 may be wound up or unwound to raise or lower the gripping device 100 as required. One or more motors or other means may be provided to effect or control the winding up or unwinding of the tethers 41.

[0043] As can be seen in FIG. 5, the body 33 of the illustrated bot 31 has an upper portion 45 and a lower portion 47. 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. The lifting assembly 102 is on top of the lower portion. However, in other embodiments, it may be on the upper portion 45. The lower portion 47 comprises a container receiving space or cavity for receiving at least a portion of the container 9 raised by the lifting assembly 102 comprising the lifting mechanism 39. The container receiving space is sized such that the container 9 can fit sufficiently inside the cavity to allow the bot 31 to move across the track structure 13 on top of the storage structure 1 without the underside of the container 9 getting caught on the track structure 13 or another part of the storage structure 1. When the bot 31 reaches its intended destination, the lifting assembly 102 controls the tether 41 to lower the gripping device 100 and the corresponding container 9 out of the cavity and to the 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.

[0044] The container accommodation space of the bot 31 may not be within the body 33 of the bot 31. For example, the container accommodation space may instead be adjacent to the body 33 of the bot 31, for example in a cantilever configuration with the weight of the body 33 of the bot 31 counterbalancing the weight of the container to be lifted. In such an embodiment, the frame or arm of the lifting mechanism 39 may project horizontally from the body 33 of the bot 31, and the tether 41 may be disposed at respective positions on the projecting frame / arm and configured to be raised and lowered from those positions to lift and lower the container into the container accommodation space adjacent the body 33. The height at which the frame / arm is attached to and projects from the body 33 of the bot 31 may be selected to provide a desired effect. For example, it may be preferred that the frame / arm projects at a high level above the body 33 of the bot 31 to allow a larger container (or multiple containers) to be lifted into the container accommodation space below the frame / arm. Alternatively, the frame / arms may be positioned to protrude lower below the body 33 (but high enough to accommodate at least one container between the frame / arms and the track structure 13) to keep the center of mass of the bot 31 lower when the bot 31 is loaded with containers.

[0045] 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 a first direction or a second direction across the tracks 17, 19 of the storage structure 1.

[0046] 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.

[0047] 6A, 6B, and 6C show perspective views of a load handling device 31 with one embodiment of a gripping device 100 suspended therefrom, and in particular from the load handling device body 33. Although not shown in these figures, the load handling device 31 includes features previously described with respect to the load handling device or bot 31, including first and second sets of wheels 35, 37 attached to the body of the load handling device 31, a cavity for receiving at least a portion of a container, and a reeled tether 41 connected at a lower end to the gripping device 100 for connecting and suspending the gripping device 100 from the load handling device 31. The load handling device 31 includes a lifting assembly 102 that reels in or unreels the reeled tether 41, which is reeled in and unreeled to raise and lower the gripping device 100, respectively, as shown in FIGS. 6A, 6B, and 6C. The gripping device 100 is lowered onto the container to be lifted until it contacts the upper edge of the container 9. Once the gripping device 100 is in position above the container 9 as shown in Figure 6A, the gripping device 100 engages and grips the container.

[0048] 7 and 8 show an embodiment of a lifting assembly 102, with FIG. 7 showing a front view of the lifting assembly 102 and FIG. 8 showing a top view of the lifting assembly 102. In this embodiment, the lifting assembly 102 includes a rectangular support plate 104, a centrally located motor 106, a gear mechanism 108, and a lifting mechanism 39 comprising four pulleys 110a, 110b, 110c, 110d fixed to or connected to the underside of the support plate 104. In this embodiment, the gear mechanism 108 is a planetary gear set (e.g., an epicyclic gear set) having a vertically extending lifting shaft 112 that rotates to reel in or unreel the tether. Each pulley 110a, 110b, 110c, 110d is disposed at or toward a corner of the lifting assembly 102, specifically at each corner of the support plate 104, and the tether extends from the planetary gear set to the four pulleys 110a, 110b, 110c, 110d and then extends downward so that the lower end of each pulley 110a, 110b, 110c, 110d connects to the gripping device 100. The motor 106 is configured to rotate the lifting shaft 112 to wind or unwind the tether around the lifting shaft, thereby raising or lowering the gripping device 110. By winding and unwinding the tether around the lifting shaft 112, the lifting shaft 112 effectively provides a spool for the tether. As the motor 106 rotates the lifting shaft 112 in a first direction, the tether is simultaneously wound around the lifting shaft 112 to lift the gripping device 100. The motor 106 rotates the lifting shaft in a second direction (opposite the first direction), simultaneously unwinding the tether from the lifting shaft 112 and lowering the gripping device 100. The motor 106 rotates the lifting shaft 112 such that the tether is wound and unwound at the same rate. In this embodiment, the motor 106 is located above the support plate 104. By locating the motor 106 in the center of the support plate 104 (as shown in FIG. 8), the weight of the motor 106 is evenly distributed across the lifting assembly 102.Additionally, by providing the motor 106 on the support plate 104 , the additional weight of the motor 106 on the lifting assembly 102 can advantageously ensure a more stable lifting and lowering of the gripping device 100 .

[0049] Figure 9 shows a top view of the lifting assembly 102 of Figures 7 and 8, showing the tethers 114a, 114b, 114c, 114d extending from the planetary gear set 108 to the four pulleys 110a, 110b, 110c, 110d. As shown in Figure 9, each pulley 110a, 110b, 110c, 110d is angled toward the planetary gear set (i.e., toward the center of the lifting assembly 102 or the center of the support plate 104). By angling the pulleys 110a, 110b, 110c, 110d toward the center, the tethers 114a, 114b, 114c, 114d extend in a straight line from the center of the lifting assembly 102 (or from the gear mechanism 108) to the pulleys. This enables the lifting assembly 102 to more uniformly and more reliably wind or unwind the tethers 114a, 114b, 114c, 114d (and thus raise or lower the gripping device 100) without the risk of the tethers 114a, 114b, 114c, 114d becoming entangled or intertwined with one another as the tethers 114a, 114b, 114c, 114d are wound or unwound by the gear mechanism 108.

[0050] 10 shows another embodiment of the lifting assembly 102. In this embodiment, the lifting mechanism 39 includes a central horizontally extending lifting shaft 116 and two spools, a first spool 118a at a first end of the lifting shaft and a second spool 118b at a second end of the lifting shaft 116. Four pulleys 110a, 110b, 110c, 110d are provided at each corner of the lifting assembly 102, in particular at each corner of the support plate 104, in this embodiment located above the support plate 104. At each end of the lifting shaft 116, two tethers extend in opposite directions from each spool through respective pulleys 110a, 110b, 110c, 110d and then extend downward to connect the lower end of each tether 114a, 114b, 114c, 114d to the gripping device 100. As shown in FIG. 10, by providing pulleys 110a, 110b, 110c, 110d at or toward each corner of the support plate 104, tethers 114a, 114b, 114c, 114d can extend downwardly such that the lower end of each tether 114a, 114b, 114c, 114d connects to a corner of the gripping device 100, thereby providing a more stable raising and lowering of the gripping device 100.

[0051] The lifting shaft 116 is configured to rotate to wind or unwind the tethers 114a, 114b, 114c, 114d around each spool 118a, 118b. When the lifting shaft 116 rotates in a first direction, the two tethers 114a, 114b at a first end of the lifting shaft are wound around the first spool 118a, and simultaneously the two tethers 114c, 114d at a second end of the lifting shaft are wound around the second spool 118b, thereby lifting the gripping device 100 (and the container when gripped by the gripping device). The lifting shaft 116 is rotated in a second direction (opposite the first direction) to simultaneously unwind the two tethers 114a, 114b from the first spool 118a and the two tethers 114c, 114d from the second spool 118b, thereby lowering the gripping device 100 (and the container when gripped by the gripping device). By providing two spools 118a, 118b, one at each end of the lifting shaft 116, each spool takes up or unwinds two tethers, thereby reducing the risk of the tethers becoming tangled. Each spool 118a, 118b can include grooves to keep the two tethers wound on the spools separate, thereby further reducing the risk of the tethers becoming tangled.

[0052] 11A-11C show views of one of the spools 118a, 118b from the embodiment of FIG. 10. FIG. 11C shows a cross-sectional view through section AA of FIG. 11B. The arrows shown in FIG. 11C illustrate the direction of the two tethers 114a, 114b, 114c, 114d extending from each spool 118a, 118b. As shown in FIG. 11C, the tethers 114a, 114b, 114c, 114d extend in opposite directions such that each tether 114a, 114b, 114c, 114d is simultaneously unwound or wound from the spool.

[0053] 12 shows another embodiment of the lifting assembly 102. In this embodiment, the lifting mechanism includes a central horizontally extending lifting shaft and four spools 118a, 118b, 118c, 118d, two spools at each end of the lifting shaft, i.e., two spools 118a, 118b at a first end of the lifting shaft 116 and two spools 118c, 118d at a second end of the lifting shaft 116. As in the embodiment of FIG. 10, four pulleys 110a, 110b, 110c, 110d are provided at each corner of the support plate 104. In this embodiment, each tether 114a, 114b, 114c, 114d extends from its own respective spool 118a, 118b, 118c, 118d through a respective pulley 110a, 110b, 110c, 110d and then extends downward where the bottom end of each tether connects to a corner of the gripping device. Each of the four tethers is connected to its own spool and extends through its own pulley before connecting to the gripping device 100. By providing four spools (i.e., one for each tether), each spool has a single tether wound or unwound thereon, thereby further reducing the risk of the tethers becoming entangled. Additionally, by providing a spool for each tether, the wound tether, when fully wound on the spool (i.e., when the tether is fully wound on the spool), takes up less space compared to an embodiment in which two or more tethers are wound on a single spool. For example, by providing a spool for each tether, the wound tethers will occupy half the amount of space compared to an embodiment in which two tethers are wound on a single spool. This advantageously results in the lifting assembly 102 requiring less space within the body 33 of the load handling device 31, e.g., the lower portion 47 of the load handling device 31 comprising a container receiving space for receiving the lifting assembly 102 and at least a portion of a container. In other words, by providing a spool for each tether, the lifting assembly 102 advantageously allows for a space gain within the container receiving space.

[0054] When the lifting shaft is rotated in a first direction to wind up the tethers, each tether is simultaneously wound up around its respective spool to lift the gripping device (and the container when gripped by the gripping device), and the lifting shaft is rotated in a second direction (opposite the first direction) to simultaneously unwind each tether from its respective spool, thereby lowering the gripping device (and the container when gripped by the gripping device).

[0055] 10 and 12, the tethers connect to the gripping device 100 via four additional pulleys, one at each corner of the gripping device. However, in other embodiments, the bottom end of each tether may connect to the gripping device without the need for additional pulleys (e.g., the bottom ends of the tethers may connect directly to the gripping device 100).

[0056] Although not shown in the embodiments of Figures 10 and 12, a motor 106 is provided for rotating the lifting shaft in first and second directions. In each of the embodiments of Figures 7 through 12, the motor 106 is configured to rotate the lifting shaft such that all of the tethers are wound or unwound simultaneously and at the same speed to raise and lower the gripping device evenly and steadily.

[0057] In some embodiments, each spool is attached to a lifting shaft via a respective slip clutch. When the lifting shaft is rotated in a first direction by the motor, the tether is wound to lift the gripping device. When the gripping device 100 reaches its top or fully lifted position (i.e., when the gripping device 100 is fully lifted by the lifting mechanism 39, e.g., into the body 33 of the bot 31), the motor can be overdriven beyond the torque of the slip clutch, so that the slip clutch slips and the spool no longer rotates. Each pulley is provided with a hard stop (e.g., a mechanical stop) that the gripping device abuts against when the gripping device reaches its fully lifted position.

[0058] By providing a slip clutch on each spool, the lifting assembly 102 can level the gripping device 100 if it becomes uneven (e.g., during lowering and / or lifting of the gripping device or due to stretching or slippage of one or more of the tethers). For example, in the embodiment of FIG. 10, the gripping device may become uneven during lowering and / or lifting of the gripping device such that a first end of the gripping device (i.e., the end lifted by the first spool at the first end of the lifting shaft) reaches its fully lifted position and abuts the pulley's hard stop, while a second end of the gripping device (i.e., the end lifted by the second spool at the second end of the lifting shaft) has not yet reached its fully lifted position. The motor continues to rotate (i.e., over-rotates) the lifting shaft such that the second end of the gripping device is lifted to its fully lifted position and abuts the pulley's hard stop. During this over-rotation of the motor to rotate the lifting shaft to lift the second end of the gripping device, the slip clutch of the first spool slips, preventing further rotation of the first spool, thereby maintaining the first end of the lifting shaft in its fully lifted position.

[0059] In the embodiment of FIG. 10, each spool is provided with a slip clutch that allows the lifting assembly 102 to smooth out any irregularities between the first and second ends of the gripping device.

[0060] In some embodiments of FIG. 12, a slip clutch is provided on each spool and each pulley is provided with a hard stop (e.g., a mechanical stop) that the gripping device abuts against when the gripping device reaches its fully raised position. As described above, by providing a slip clutch on each spool, the lifting assembly 102 can level the gripping device if it becomes uneven during descent and / or ascent. When a side or corner of the gripping device becomes uneven, the motor continues to rotate the lifting shaft until the uneven side or corner is lifted to its fully raised position and abuts against the hard stop of the pulley. In the embodiment of FIG. 12, a spool is provided on each tether. Thus, a slip clutch can be provided on each spool to control the level of each individual tether. This advantageously allows the lifting assembly 102 to control and level each corner of the gripping device if it becomes uneven.

[0061] The motor over-rotates against the hard stop each time the gripping device is lifted. This allows any uneven sides or corners of the gripping device to be lifted up to the hard stop. A slip clutch on each spool allows the motor to over-rotate and lift any uneven sides or corners of the gripping device while still maintaining any sides or corners of the gripping device in a fully lifted position already against the hard stop. This advantageously allows the lifting assembly to calibrate and level the gripping device each time it is lifted.

[0062] In embodiments including a slip clutch, the slip clutch is located at the center of the spool (see FIG. 11C) and includes a shaft or hollow bore that is attached to the lifting shaft, thereby attaching the spool to the lifting shaft. The slip clutch is preferably an electromagnetic clutch (e.g., a hysteresis / magnetic particle clutch). These clutches operate by electrical actuation, especially where actuation of the clutch does not require contact of the clutch's internal elements, thereby reducing clutch wear over time. By providing an electromagnetic clutch, they advantageously provide a reliable and durable method for leveling the gripping device. The slip clutch is a fixed torque clutch that slips at a predetermined torque.

[0063] In the embodiment of Figures 7-10 and 12, the lifting assembly 102 includes a support plate 104 for supporting the spool. The support plate 104 may also be provided to support the motor 106, as shown in the embodiment of Figures 7-9. However, in other embodiments, the support plate 104 may not be required. The spool and / or motor 106 may be supported by alternative support means including, for example, one or more vertical shafts.

[0064] 13 illustrates a lifting and lowering mechanism 139 of another embodiment of the lifting assembly 102. In this embodiment, the lifting mechanism 139 includes a central horizontally extending lifting shaft 120 and four spools: two spools 122a, 122b at a first end of the lifting shaft 120 and two spools 122c, 122d at a second end of the lifting shaft 120. The lifting assembly 102 comprises four pulleys 124a, 124b, 124c, 124d, one at each corner of the lifting assembly 102, and four tethers 114a, 114b, 114c, 114d, each tether extending from a respective spool 122a, 122b, 122c, 122d to a respective pulley 124a, 124b, 124c, 124d and then extending downwardly where the lower end of each tether 114a, 114b, 114c, 114d connects to the gripping device 100, e.g., to a corner of the gripping device (not shown in FIG. 13). The two tethers 114a, 114b at the first end of the lifting shaft extend in opposite directions from the two spools 122a, 122b at the first end of the lifting shaft 102, and the two tethers 114c, 114d at the second end of the lifting shaft 120 extend in opposite directions from the two spools 122c, 122d at the second end of the lifting shaft, so that each tether can pass through a pulley at the corner of the lifting assembly 120. In this embodiment, each of the four tethers is connected to its own spool so that a single tether is wound or unwound on each spool. This advantageously ensures that the wound tethers on each spool occupy less space compared to an embodiment in which two or more tethers are wound on a single spool, for example as described in connection with the embodiment of FIG. 10. Providing a spool for each tether also advantageously reduces the risk of the tethers becoming tangled as they are wound or unwound to raise or lower the gripping device.

[0065] In some embodiments, the lifting mechanism 139 of Figure 13 includes a slip clutch on each spool, i.e., each spool is attached to the lifting shaft via a respective slip clutch, as described in connection with the embodiment of Figure 12. As discussed above, this allows the lifting assembly 102 of the embodiment of Figure 13 to level corners of the gripping device 100 if the corners become uneven during lifting and / or lowering.

[0066] In other embodiments, the lifting assembly 102 may include two spools, one on each end of the lifting shaft, and the spools may include one or more grooves to separate the two tethers on each spool.

[0067] The lifting shafts are configured to rotate to wind or unwind the tether around each spool. When the lifting shafts are rotated in a first direction to wind up the tether, each tether is simultaneously wound around its respective spool to lift the gripping device (and the container when gripped by the gripping device). The lifting shafts are rotated in a second direction (opposite the first direction) to simultaneously unwind each tether from its respective spool, thereby lowering the gripping device (and the container when gripped by the gripping device). The tethers are wound or unwound simultaneously and at the same rate to raise or lower the gripping device evenly and steadily.

[0068] The lifting assembly 102 includes a motor 106 configured to rotate a lifting shaft 120 in a first and second direction to wind or unwind the tethers around their spools. The motor 106 is coupled to a central, horizontally extending lifting shaft 120 and rotates the lifting shaft in a first and second direction.

[0069] The motor 106 is encased or partially surrounded by a block that protects the motor 106 and helps hold the motor 106 in place. The four pulleys 124a, 124b, 124c, 124d are also held within a block that is suspended or connected to the load handling device by vertical rods (not shown), thereby connecting the lifting assembly 102 to the load handling device.

[0070] The blocks are also connected by rods 128 that assemble each pulley 124a, 124b, 124c, 124d to a corner of the rectangular lifting assembly 102. Each block that holds a pulley 124a, 124b, 124c, 124d includes a cutout to allow a tether 114a, 114b, 114c, 114d to extend from a spool to a pulley within the block.

[0071] 14A and 14B show another embodiment of the lifting assembly 102. In this embodiment, the lifting assembly 102 includes a lifting mechanism 239 with a gear mechanism 130 mounted on the gripping device. The gear mechanism 130 winds and unwinds four tethers 114a, 114b, 114c, 114d. These tethers are connected to the gear mechanism 130 via four pulleys 132a, 132b, 132c, 132d located at the corners of the gripping device 100. The tethers 114a, 114b, 114c, 114d extend upward from the pulleys of the gripping device 100 to four pulleys 110a, 110b, 110c, 110d located within the body 33 of the load handling device 31. As the gear mechanism 130 winds up the tethers 114a, 114b, 114c, 114d, the gripping device 100 rises upward toward the load handling device 31. With the gear mechanism 130 on the gripping device 100, it can be described as the gripping device 100 "rising" as the gear mechanism 130 winds up the tether, rather than the gripping device 100 lifting up as the tethers 114a, 114b, 114c, 114d are wound up, for example, if the gear mechanism were provided above the gripping device (e.g., in the load handling device body 33). In other words, the lifting force comes from the gripping device 100, not from a gear mechanism provided in the body 33 of the load handling device 31. As the gear mechanism 130 unwinds the tethers 114a, 114b, 114c, 114d, the gripping device 100 descends.

[0072] Providing the gear mechanism 130 on the gripping device 100 adds weight to the gripping device 100. This advantageously helps the gripping device 100 to be lifted and lowered in a smoother, level, and stable manner (e.g., as compared to a lighter weight gripping device).

[0073] 14B, the lifting mechanism 239 includes a motor 106 configured to drive or rotate a gear mechanism 130 to reel in or unreel the tether. The motor 106 is provided on the gripping device 100. This advantageously provides additional weight to the gripping device 100, helping the gripping device 100 to be lifted and lowered in a smooth and level manner. By providing the gear mechanism 130 and / or the motor 106 on the gripping device 100, the lifting assembly 102 achieves a redistribution of its mass, which advantageously results in a smoother, level, and stable lifting and lowering of the gripping device 100.

[0074] Additionally, by providing the gripping device 100 with a motor 106, the gripping device 100 itself is powered without the need for a power cable extending from the powered load handling device 31 to the gripping device 100. By providing the gripping device 100 with a motor 106, the gripping device 100 can function as an autonomous element that may be tasked with a mission (e.g. pick a container at a particular location in the storage structure and 11 containers deep). The gripping device 100 can use its own power source and sensors (if provided) to perform the task. The gripping device 100 can use its own power from the motor 106 to drive other elements on the gripping device 100 (e.g. sensors, grippers, LEDs, etc.).

[0075] The motor 106 and gear mechanism 130 are located in the center of the gripping device 100. This helps ensure that the gripping device 100 remains level as it rises and falls. In this embodiment, the gear mechanism 130 is a planetary gear set (e.g., an epicyclic gear set) that has a vertically extending lift shaft 134 that acts as a spindle for the tethers 114a, 114b, 114c, 114d as the gear set 130 rotates to wind or unwind the tethers.

[0076] In other embodiments, the motor 106 may be provided within the load handling device.

[0077] In some embodiments, the lifting mechanism 239 can include a weight on the gripping device 100 to add weight to the gripping device instead of or in addition to providing a gear mechanism 130 and / or a motor 106 on the gripping device 100.

[0078] FIG. 15 illustrates another embodiment of the lifting assembly 102. In this embodiment, the lifting mechanism 339 includes a gear mechanism, in this embodiment in the form of a worm gear 136 attached to a horizontally extending central shaft 138 disposed within the load handling device body 33. Although not shown, the lifting assembly 102 includes a motor 106 (e.g., within the load handling device body 33) that rotates or drives the worm gear 136 to wind or unwind the four tethers 114a, 114b, 114c, 114d that wrap around the worm gear 136. The worm gear 136 includes four circumferential grooves or tracks along the outside of the worm gear (i.e., the drum of the worm gear) into which the tethers are wound or unwound. By providing four separate circumferential grooves, each tether can wind and unwind from the worm gear within its own groove, thereby reducing or eliminating the risk of tangling between the tethers as the worm gear rotates.

[0079] As the worm gear rotates to wind the tether and raise the gripping device 100, the worm gear 136 moves or slides along the shaft 138 in a first axial direction (e.g., toward the right). As the worm gear rotates to unwind the tether and lower the gripping device 100, the worm gear 136 moves or slides back along the shaft 138 in the opposite direction (i.e., opposite the first axial direction, e.g., toward the left). Allowing the worm gear to move back and forth (to the right or left) along the shaft 138 ensures smoother and more uniform winding and unwinding of the tether from the worm gear 136 as the tether is wound or unwound from the worm gear 136. The worm gear 136 can move along the shaft 138 due to the force of the tether as the tether is wound onto or unwound from the worm gear 136. In other embodiments, the gear mechanism includes a spring that can urge a worm gear back and forth along shaft 138 as the tether is wound or unwound.

[0080] In some embodiments, the drum of the worm gear 136 may be attached to the shaft 138 via an ultra-low friction rail. This allows the rotational force of the worm gear 136 alone to be sufficient to wind the tether around and unwind it from the worm gear, causing the worm gear to move back and forth on the shaft 138. In other words, the worm gear can "self-feed" the tether. Examples of ultra-low friction materials that may be used include PTFE. Those skilled in the art will know many other materials suitable for ultra-low friction rails.

[0081] The tethers 114a, 114b, 114c, 114d extend downward from the worm gear 136 to the four pulleys 142a, 142b, 142c, 142d of the gripping device 100 and are positioned approximately in the center of the gripping device 100, retaining the tethers 114a, 114b, 114c, 114d toward the center of the lifting assembly 102. This results in a more space efficient lifting assembly 102 that requires less space within the load handling device 31. Retaining the tethers 114a, 114b, 114c, 114d toward the center in this manner also results in easier winding of the tethers 114a, 114b, 114c, 114d around the worm gear 136. From the centrally located pulleys 142a, 142b, 142c, 142d, the tether extends along the gripping device to four pulleys 144a, 144b, 144c, 144d at the corners of the gripping device 100. This ensures a more stable and level ascent and descent of the gripping device as the tethers 114a, 114b, 114c, 114d are wound and unwound by the worm gear 136.

[0082] In the embodiment of FIG. 15, a single, substantially centrally located worm gear is provided for winding and unwinding the tether. In other embodiments, the lifting assembly includes a gear mechanism in the form of two worm gears, each configured to wind and unwind two tethers. By providing two worm gears instead of one, the weight of the gear mechanism may be more evenly distributed across the lifting assembly 102, resulting in a more balanced lifting assembly 102. Additionally, by providing two worm gears, each supporting two tethers, winding and unwinding the tether may be simplified and the risk of the tether becoming tangled as it is wound onto and unwound from the worm gears may be reduced or eliminated.

[0083] In the above embodiment, all of the cables are wound and unwound using a single motor 106. However, in other embodiments, more than one motor 106 may be used, if desired. In the embodiment of FIG. 16, the lifting assembly 102 has four spools 201, 202, 203, and 204 for winding and unwinding the respective tethers. Spools 201 and 202 are on drive shaft 205, and spools 203 and 204 are on drive shaft 206. Drive shafts 205 and 206 are configured to rotate in opposite directions when driven by a motor. By rotating drive shafts 205 and 206 in opposite directions, each tether 114a-d can be located at or near a corner of the lifting assembly, similar to the above embodiment. In particular, as shown in FIG. 16, the point at which each tether is wound or unwound onto or from the spool is at or near a respective corner of the lifting assembly. This allows the tether to connect to the gripping assembly 100 at each corner of the gripping assembly, providing increased stability when raising and lowering the gripping assembly. FIG. 16 shows one example of how the drive shafts 205 and 206 may be rotated in opposite directions. The drive shafts 205 and 206 are connected to pulleys 210 and 211, respectively. A motor applies torque to pulley 207. A timing belt 208 transmits torque to pulleys 209, 210, and 211 to ensure that spools 201 and 202, and spools 203 and 204 rotate in opposite directions. In particular, pulleys 207 and 209 are disposed around pulley 211 to rotate in opposite directions to pulley 210. It will be appreciated that this is just one exemplary way that the drive shafts 205 and 206 may be rotated in opposite directions when driven by a motor.

[0084] It will be appreciated that, without limitation, spools 201, 202, 203, and 204 are particularly suited for woven polyester tape or woven belts (e.g., seat belts) having conductive elements or wiring woven into the belts described above. If a wire tether is used, each spool 201, 202, 203, and 204 may be threaded to form a groove that receives / releases the wire tether as it is wound / unwound. Such a spool 500 is shown in FIG. 17, which may be used with any of the embodiments described above. The depth of groove 510, and the overall configuration of the groove, may be selected depending on the characteristics of wire 515, such as diameter and length.

[0085] Additionally, a slip clutch may be included with each spool, i.e., each spool 201, 202, 203, and 204 is attached to the lifting shaft via a respective slip clutch, as described in connection with the embodiment of Figures 12 and 13. As discussed above, this allows the lifting assembly 102 to level the corners of the gripping device 100 if they become uneven during lifting and / or lowering.

[0086] In the embodiment of FIG. 18, lifting assembly 102 has four spools 301, 302, 303, and 304 for winding and unwinding respective tethers 114a-d. Spools 301 and 302 are on drive shaft 305, and spools 303 and 304 are on drive shaft 306. Drive shafts 305 and 306 are configured to rotate in opposite directions when driven by a motor. The drive shafts are operatively coupled by meshing gears 307 and 308. Drive shaft 305 (and thus gear 307, spools 301 and 302) and drive shaft 306 (and thus gear 308, spools 303 and 304) are on either side of a central axis 310 of the lifting assembly, adjacent to central axis 212. Central axis 310 extends in a longitudinal direction parallel to the longitudinal axes of drive shafts 305 and 306. The tether from each spool extends to a respective pulley 311, 312, 313, and 314 located at or near a corner of the lifting assembly, similar to the above embodiment. In particular, as shown in FIG. 18, the point at which each tether winds on or off of the pulleys 311, 312, 313, and 314 is at or near a respective corner of the lifting assembly. This allows the tether to connect to the gripping assembly 100 at each corner of the gripping assembly, improving stability when raising and lowering the gripping assembly. When either of the drive shafts 305, 306 is driven by the motor to rotate in a first direction, the other drive shaft rotates in a second direction opposite the first direction through the meshing of gears 307 and 308. That is, gear 307 (and thus spools 301 and 302) and gear 308 (and thus spools 303 and 304) rotate in opposite directions to wind and unwind the respective tethers. It will be appreciated that this is just one exemplary way in which drive shafts 305 and 306 may be caused to rotate in opposite directions when driven by a motor.

[0087] It will be appreciated that, without limitation, spools 301, 302, 303, and 304 are particularly suited for woven polyester tape or woven belts (e.g., seat belts) having conductive elements or wiring woven into the belts described above. If a wire tether is used, each spool 301, 302, 303, and 304 may be threaded to form a groove that receives / releases the wire tether as it is wound / unwound. Such a spool 500 is shown in FIG. 17 and may be used with any of the embodiments described above. The depth of groove 510, and the overall configuration of the groove, may be selected depending on the characteristics of wire 515, such as diameter and length.

[0088] Additionally, a slip clutch may be included with each spool, i.e., each spool 301, 302, 303, and 304 is attached to the lifting shaft via a respective slip clutch, as described in connection with the embodiment of Figures 12 and 13. As discussed above, this allows the lifting assembly 102 to level the corners of the gripping device 100 if they become uneven during lifting and / or lowering.

[0089] In the embodiment of FIG. 19, the lifting assembly 102 has four spools 401, 402, 403, and 404 for winding and unwinding the respective tethers. Spools 401 and 402 are on drive shaft 405, and spools 403 and 404 are on drive shaft 406. Drive shafts 405 and 406 are configured to rotate in opposite directions when driven by a motor. By rotating drive shafts 405 and 406 in opposite directions, the tethers can be located at or near the corners of the lifting assembly, similar to the above embodiments. In particular, as shown in FIG. 19, the points at which each tether is wound onto or unwound from the spool are at or near the respective corners of the lifting assembly. This allows the tethers to connect to the gripping assembly at the respective corners of the gripping assembly 100, providing increased stability when raising and lowering the gripping assembly. FIG. 19 shows one example of how drive shafts 405 and 406 may be rotated in opposite directions. The motor applies a torque to shaft 411, which includes first worm gear 407 and second worm gear 408. First and second worm gears 407, 408 are configured (or threaded) to rotate respective gears 409 and 410 in opposite directions. Thus, gear 409 rotates drive shaft 405 in a first direction, and gear 410 rotates drive shaft 406 in a second direction opposite the first direction. That is, gear 409 (and thus spools 401 and 402) and gear 410 (and thus spools 403 and 404) rotate in opposite directions to wind and unwind the respective tethers.

[0090] It will be appreciated that, without limitation, spools 401, 402, 403, and 404 are particularly suited for woven polyester tape or woven belts (e.g., seat belts) having conductive elements or wiring woven into the belt as described above. If a wire tether is used, each spool 401, 402, 403, and 404 may be threaded to form a groove that receives / releases the wire tether as it is wound / unwound. Such a spool 500 is shown in FIG. 17, and this spool may be used with any of the embodiments described above. The depth of the groove 510, and the overall configuration of the groove, may be selected depending on the characteristics of the wire 515, such as diameter and length.

[0091] Additionally, slip clutches may be included in each spool, i.e., each spool 401, 402, 403, and 404 is attached to the lifting shaft via a respective slip clutch, as described in connection with the embodiment of Figs. 12 and 13. As described above, this allows the lifting assembly 102 to level the corners of the gripping device 100 if they become uneven during lifting and / or lowering. All optional and preferred features and modifications of the described embodiments and dependent claims can be used in all aspects of the invention taught herein. Furthermore, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments, can be combined and exchanged with each other.

Claims

1. 1. A container lifting assembly for raising and / or lowering containers stacked in a grid storage structure, comprising: a gripping device configured to releasably grip the container; a lifting mechanism for lifting and lowering the gripping device, The lifting mechanism includes: a gear mechanism configured to reel in and / or unreel at least one tether; a motor configured to operate the gear mechanism to reel in and / or unreel the at least one tether; A container lifting assembly, wherein the at least one tether is connected to the gripping device such that winding and unwinding of the at least one tether is configured to raise and lower the gripping device.

2. 2. The container lifting assembly of claim 1, wherein the gear mechanism comprises at least one spool, the at least one tether extending from the at least one spool prior to extending and connecting to the gripping device, and the gear mechanism is configured to wind or unwind the at least one tether around the at least one spool.

3. 3. A container lifting assembly as described in claim 1 or 2, wherein the lifting mechanism comprises at least one pulley, and the at least one tether extends from at least one spool to the at least one pulley before extending and connecting to the gripping device.

4. 4. A container lifting assembly as described in claim 1, 2 or 3, wherein the lifting mechanism comprises at least a pair of tethers and a spool for each pair of tethers, and the gear mechanism is configured to wind or unwind the at least pair of tethers around the spools.

5. 5. The container lifting assembly of claim 4, wherein each tether of the pair of tethers extends in opposite directions from the spool to a pulley before extending and connecting to the gripping device.

6. A container lifting assembly according to any one of claims 1 to 5, wherein the gear mechanism comprises a spool for each tether.

7. A container lifting assembly according to any preceding claim, wherein the lifting mechanism comprises a pulley for each tether.

8. 8. A container lifting assembly according to claim 1, wherein the lifting mechanism comprises four tethers, each tether extending from the gear mechanism to a corner of the gripping device.

9. The lifting mechanism includes: a horizontally extending lifting shaft and two spools, a first spool at a first end of said lifting shaft and a second spool at a second end of said lifting shaft, said second end being opposite said first end; 9. A container lifting assembly as claimed in any one of claims 1 to 8, comprising two tethers at the first end of the lifting shaft configured to be wound onto and unwound from the first spool, and two tethers at the second end of the lifting shaft configured to be wound onto and unwound from the second spool.

10. The lifting mechanism includes: a horizontally extending lifting shaft and four spools, two spools at a first end of the lifting shaft and two spools at a second end of the lifting shaft, the second end being opposite the first end; 9. A container lifting assembly as described in any one of claims 1 to 8, comprising two tethers at the first end of the lifting shaft, each tether configured to be wound onto and unwound from a respective spool at the first end of the lifting shaft, and two tethers at the second end of the lifting shaft, each tether configured to be wound onto and unwound from a respective spool at the second end of the lifting shaft.

11. The lifting mechanism includes: a horizontally extending lifting shaft, a first spool, a second spool, a third spool, and a fourth spool, wherein the first and second spools are disposed at or near a first end of the horizontally extending lifting shaft, and the third and fourth spools are disposed at or near a second end of the horizontally extending lifting shaft opposite the first end; 2. The container lifting assembly of claim 1, comprising a first tether, a second tether, a third tether, and a fourth tether configured to be wound and unwound from the first, second, third, and fourth spools, respectively, wherein the first and second spools are configured to rotate in opposite directions to the third and fourth spools to wind and unwind the first, second, third, and fourth tethers.

12. 12. A container lifting assembly as described in claim 11, wherein said first and second spools are on a first shaft and said third and fourth spools are on a second shaft, and wherein said gear mechanism comprises first and second pulleys on said first and second shafts, respectively, said first and second pulleys being driven in opposite directions via a timing belt.

13. 13. The container lifting assembly of claim 12, wherein the gear mechanism further comprises a third pulley and a fourth pulley disposed about either the first pulley or the second pulley to effect opposite rotation of the first pulley and the second pulley via the timing belt.

14. 14. A container lifting assembly as claimed in claim 13, wherein any one of the first, second, third and fourth pulleys is directly driven by the motor.

15. 12. The container lifting assembly of claim 11, wherein the gear mechanism comprises first and second worm gears on a shaft driven by the motor, the worm gears configured to effect rotation of the first and second spools in an opposite direction to the third and fourth spools.

16. 16. A container lifting assembly as described in claim 15, wherein the first and second spools are on a first shaft and the third and fourth spools are on a second shaft, and wherein the gear mechanism further comprises first and second gears on the first and second shafts, respectively, and the first and second gears are driven via the first and second worm gears, respectively.

17. The lifting mechanism includes: a horizontally extending lifting shaft, a first spool, a second spool, a third spool, and a fourth spool, wherein the first and second spools are disposed adjacent to a first side or proximate a central axis of the horizontally extending lifting shaft, and the third and fourth spools are disposed adjacent to a second side or proximate a central axis of the horizontally extending lifting shaft, wherein the first side is opposite the second side; 2. The container lifting assembly of claim 1, comprising a first tether, a second tether, a third tether, and a fourth tether configured to be wound and unwound from the first, second, third, and fourth spools, respectively, wherein the first and second spools are configured to rotate in opposite directions to the third and fourth spools to wind and unwind the first, second, third, and fourth tethers.

18. 18. A container lifting assembly as described in claim 17, wherein said first and second spools are on a first shaft and said third and fourth spools are on a second shaft, said first and second shafts being parallel to said central axis.

19. 20. A container lifting assembly as described in claim 18, wherein the gear mechanism comprises first and second gears on the first and second shafts, respectively, wherein the first and second gears mesh such that the motor driving either the first or second shaft rotates the other of the first or second shaft.

20. 20. A container lifting assembly as claimed in claim 19, wherein each tether is coupled to a respective pulley located at or near a respective corner of the lifting assembly.

21. 21. A container lifting assembly as claimed in any one of claims 11 to 20, wherein the first, second, third and fourth tethers are configured such that the point at which each tether is wound onto or unwound from a respective spool or pulley is at or near a respective corner of the lifting assembly.

22. 22. A container lifting assembly as claimed in claim 21, wherein each tether connects to the gripping device at or near a respective corner of the gripping device.

23. 23. A container lifting assembly as claimed in any one of claims 2 to 22, wherein at least one spool is provided with a slip clutch.

24. 24. A container lifting assembly as claimed in any one of claims 9 to 23, wherein at least one spool is attached to the lifting shaft via a slip clutch.

25. A container lifting assembly as claimed in any one of claims 22 or 24, wherein the slip clutch is an electromagnetic clutch.

26. 26. A container lifting assembly as claimed in any one of claims 2 to 25, wherein the at least one spool is provided with at least one groove along its circumference into which a wire tether is configured to be wound.

27. 27. A container lifting assembly as claimed in any one of claims 1 to 26, wherein the gear mechanism is provided on the gripping device such that when the gear mechanism winds up the at least one tether, the gripping device rises towards the top of the lifting assembly.

28. 28. A container lifting assembly according to any one of claims 1 to 27, wherein the motor is provided on the gripping device such that the gripping device is a self-powered element.

29. 29. A container lifting assembly according to any one of claims 1 to 28, wherein the gear mechanism comprises a planetary gear set.

30. 30. A container lifting assembly as claimed in any one of the preceding claims, wherein the gear mechanism comprises a worm gear.

31. 31. A container lifting assembly as described in claim 30, wherein the worm gear includes at least one groove along its circumference into which the at least one tether is configured to be wound or unwound.

32. 32. A container lifting assembly according to any one of claims 1 to 31, wherein the at least one tether is in the form of a tape.

33. 33. A container lifting assembly according to any one of claims 1 to 32, wherein the at least one tether comprises a conductive material or element woven into the tether.

34. 34. A container lifting assembly as claimed in any one of claims 1 to 33, wherein the at least one tether comprises a woven polyester tape.

35. 1. A cargo handling device for lifting and moving containers stacked in a grid storage structure comprising a plurality of tracks arranged in a grid pattern above the stack of containers, the device comprising: a body housing a drive mechanism operatively arranged to move a load handling device on said grid; 35. A load handling device comprising: a container lifting assembly according to any one of claims 1 to 34 configured to raise and lower the gripping device relative to the body for raising and lowering containers stacked in a stack.

36. 36. The load handling device of claim 35, wherein the lifting assembly is disposed within a body of the load handling device.

37. A method of lifting and lowering a container from a stack of containers, the method comprising the load handling device of any one of claims 35 or 36, the method comprising the steps of: activating the gear mechanism to rewind the at least one tether and lower the gripping device relative to the body; actuating the gripping device to grip a container; and actuating the gear mechanism to wind the tether and raise the gripping device relative to the body.

38. 38. The method of claim 37, further comprising the step of raising the gripping device relative to the body to lift the container into a cavity of the load handling device.

39. 1. A system comprising: A load handling device according to claim 35 or 36; a storage structure for receiving containers stacked in a stack, said storage structure including a first set of tracks extending in a first direction and a second set of tracks extending in a second direction transverse to said first direction, said load handling device configured to travel on said first and second sets of tracks; and a control utility configured to control the load handling devices to lift containers from stacks below the grate and / or lower containers into the grate.

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