GB2632099A

GB2632099A - Load handling devices and storage and retrieval systems

Info

Publication number: GB2632099A
Application number: GB2310969.7A
Authority: GB
Inventors: Fredrik Jonathan Nilsson Måns; Sverker Ture Lindbo Lars
Original assignee: Ocado Innovation Ltd
Current assignee: Ocado Innovation Ltd
Priority date: 2023-07-18
Filing date: 2023-07-18
Publication date: 2025-01-29
Also published as: GB202310969D0; WO2025016978A1

Abstract

A load handling device (120, Fig 7) associated with storage containers (101) arranged in stacks 102 comprising a body 121 mounted on movement means in the form of wheels (122a, 122b Fig 7). Container displacement device (123-126) mounted on body 121 capable of moving at least one of the stacked containers 102 vertically (lift or lower) by lifting device 126, and horizontally (forward or rearward) relative to body 121 by support assembly 125. Body 121 comprises opening 127 through which an outgoing container 101a may pass after being moved from the support of a lower container 101 container. An associated storage and retrieval system, and method of operation, are also disclosed.

Description

LOAD HANDLING DEVICES AND STORAGE AND RETRIEVAL SYSTEMS Field of the invention The disclosure herein relates to load handling devices for use in storage and retrieval systems and storage and retrieval systems comprising such load handling devices. In particular, the disclosure relates to storage systems comprising a plurality of freestanding stacks of storage containers and load handling devices for depositing storage containers in and retrieving storage containers from the stacks.

Background

Some commercial and industrial activities require systems that enable the storage and retrieval of a large number of different products. One known type of system for the storage and retrieval of items in multiple product lines involves arranging storage bins or containers in stacks on top of one another, the stacks being arranged in rows. The storage bins or containers are accessed from above, removing the need for aisles between the rows and allowing more containers to be stored in a given space.

Methods of handling containers stacked in rows have been well known for decades. In some such systems, for example as described in US2701065A, freestanding stacks of containers are arranged in rows in order to reduce the storage volume associated with storing such containers while still providing access to a specific container if required. Access to a given container is made possible by providing relatively complicated hoisting mechanisms which can be used to stack containers and to remove given containers from stacks. The cost of such systems are, however, impractical in many situations and they have mainly been commercialised for the storage and handling of large shipping containers.

The concept of using freestanding stacks of containers and providing a mechanism to retrieve and store specific containers has been developed further, for example as described in EP0767113B. EP0767113B discloses a mechanism for removing a plurality of stacked containers using a robotic load handler in the form of a rectangular tube which is lowered around the stack of containers, and which is configured to be able to grip a container at any level in the stack. In this way, several containers can be lifted at once from a stack. The movable tube can be used to move several containers from the top of one stack to the top of another stack, or to move containers from a stack to an external location and vice versa.

In the system described in EP0767113B, the robot requires a large amount of space above the stacks, at least one stack high in order to be able to move over the stacks. This can be disadvantageous in some implementations where vertical space is limited. Raising a heavy gripper and heavy contained load into the space above the stored stacks and moving them quickly through this space requires a substantial robot together with substantial supporting structure. Such a robot and support structure is expensive to manufacture, install and commission.

Summary of the invention

According to a first aspect, there is provided a load handling device for lifting and moving storage containers arranged in stacks in a storage system. The load handling device comprises a body mounted on movement means, a container displacement device mounted to the body, wherein the container displacement device is arranged to move one or more stacked storage containers supported thereon vertically and horizontally relative to the body, and a container lifting device mounted to the body, wherein the container lifting device is arranged to move a storage container supported thereon vertically relative to the body.

The container displacement device may be arranged to move one or more stacked storage containers supported thereon vertically and horizontally relative to the body in order to extract and insert one or more stacked storage containers into a stack. The container lifting device may then be arranged to move one or more stacked storage containers supported thereon vertically relative to the body in order to raise and lower one or more stacked storage containers. Coordinating the operation of the container displacement device and the container lifting device therefore enables the load handling device to laterally insert storage containers in to and extract storage containers from a stack. The one or more stacked storage containers comprises either a single storage container or a plurality of storage containers that are stacked.

The container displacement device may be arranged to move one or more stacked storage containers supported thereon horizontally relative to the body between a forward position and a rearward position. The load handling device may be arranged such that, when one or more stacked storage containers supported on the container displacement device are in the forward position, the one or more stacked storage containers supported on the container displacement device are located in front of the body.

The load handling device may be arranged such that, when one or more stacked storage containers supported on the container displacement device are in the forward position, the one or more stacked storage containers supported on the container displacement device are horizontally aligned with one or more stacked storage containers supported on the container lifting device. The load handling device may be arranged such that, when one or more stacked storage containers supported on the container displacement device are in the rearward position, the one or more stacked storage containers supported on the first container lifting device are horizontally offset relative to one or more stacked storage containers supported on the container lifting device.

The load handling device may be configured to operate as an automated or autonomous vehicle. The stacks of storage containers are supported on a surface, and the movement means may be arranged to allow the load handling device to move across the surface.

The load handling device may be arranged such that the container lifting device can move one or more stacked storage containers supported on the container lifting device vertically past one or more stacked storage containers supported on the container displacement device.

The container displacement device may comprise a first container support assembly arranged to support one or more stacked storage containers, a first lifting mechanism arranged to move the first container support assembly vertically relative to the body, and a transfer mechanism arranged to move the one or more stacked storage containers supported on the first container support assembly horizontally relative to the body between a forward position and a rearward position.

The container lifting device may then comprise a second container support assembly arranged to support one or more stacked storage containers, and a second lifting mechanism arranged to move the second container support assembly vertically relative to the body. The second container support assembly may be arranged to engage a storage container and lift the engaged storage container when raised by the second lifting mechanism, and thereby also lift any storage containers stacked on top of the engaged storage container.

The first container support assembly may be arranged to engage a storage container and lift the engaged storage container when raised by the first lifting mechanism, and thereby also lift any storage containers stacked on top of the engaged storage container. The first container support assembly may be arranged to extend forward from the body of the load handling device such that the first container support assembly can be located under at least a portion of a storage container that is immediately forward of the body and engage the storage container when raised by the first lifting mechanism. The first container support assembly may be arranged to extend forward from the body of the load handling device when in the forward position.

The second container support assembly may be arranged to engage storage container and lift the engaged storage container when raised by the second lifting mechanism, and thereby also lift any storage containers stacked on top of the engaged storage container. The second container support assembly may be arranged to extend forward from the body of the load handling device such that the second container support assembly can be located under at least a portion of a storage container that is immediately forward of the body and engage the storage container when raised by the second lifting mechanism.

The body may comprise an opening arranged to allow one or more stacked storage containers supported on the first container support assembly to move at least partially into the body of the load handling device when moving between the forward position and the rearward position The first container support assembly may be movably mounted to a first vertical track provided on the body and the second container support assembly movably mounted to a separate, second vertical track provided on the body. The first vertical track may be spaced rearward relative to the second vertical track.

The transfer mechanism may be arranged to move the first container support assembly horizontally relative to the body between a forward position and a rearward position. The load handling device may be arranged such that, when the first container support assembly is in the rearward position, the first container support assembly does not horizontally overlap with the second container support assembly. The load handling device may be arranged such that, when the first container support assembly is in the forward position, the first container support assembly is horizontally aligned with the second container support assembly.

The transfer mechanism may comprise a conveyor mounted on the first container support assembly and that is arranged to convey one or more stacked storage containers supported on the first container support assembly between the forward position and the rearward position. When in the forward position, the one or more stacked storage containers may be located towards a forward end of the first container support assembly and, when in the rearward position, in the one or more stacked storage containers may be located towards a rearward end of the first container support assembly.

The load handling device may further comprise a robotic arm arranged to pick items from a container supported by the load handling device. The load handling device may then further comprise a receptacle support arranged to support a receptacle for receiving and holding items, wherein the robotic arm is arranged to deposit items picked from a storage container supported by the load handling device into a receptacle located on the receptacle support. The load handling device may comprise a plurality of receptacle supports, each arranged to support a receptacle for receiving and holding items. The robotic arm may be mounted to the body. The robotic arm may be movably mounted to the body and be arranged to move vertically relative to the body. The robotic arm may be supported on the first container support assembly.

According to a second aspect there is provided a storage and retrieval system comprising a plurality of freestanding stacks of storage containers stored in a workspace, and at least one load handling device according to the first aspect.

The storage and retrieval system may further comprise a central control facility for controlling and coordinating the movement and operation of the load handling devices. The stacks of storage containers may be arranged in rows that are grouped together to form separate blocks of stacks, with each block of stacks being at least partially bounded by intersecting aisles.

According to a third aspect there is provided a method of operating a load handling device to insert one or more ingoing storage containers into a destination stack of storage containers. The method comprises (i) using a container displacement device of the load handling device to lift the one or more ingoing storage containers and to support the one or more ingoing storage containers in a rearward position, (ii) using a movement means of the load handling device to position the load handling device with the destination stack immediately in front of the load handling device, (iii) using a container lifting device of the load handling to lift at least a portion of the storage containers of the destination stack, (iv) using the container displacement device to move the one or more ingoing storage containers horizontally from the rearward position to a forward position in which the one or more ingoing storage containers are aligned beneath the lifted portion of the destination stack and to lower the one or more ingoing storage containers, and (v) using the container lifting device to lower the lifted portion of the destination stack on to the one or more ingoing storage containers.

The method may further comprises, prior to positioning the load handling device with the destination stack immediately in front of the load handling device, using the container displacement device to move the one or more ingoing storage containers horizontally from the forward position to the rearward position According to a fourth aspect there is provided a method of operating a load handling device to extract one or more outgoing storage containers from a source stack of storage containers. The method comprises (i) using a movement means of the load handling device to position the load handling device with the source stack immediately in front of the load handling device, (ii) using a container lifting device of the load handling to lift at least a portion of the storage containers of the source stack, (iii) using a container displacement device of the load handling device to lift the one or more outgoing storage containers and to move the one or more outgoing storage containers from a forward position to a rearward position in which the one or more ingoing storage containers do not horizontally overlap with the lifted portion of the source stack, and (iv) using the container lifting device to lower the lifted portion of the source stack on to the one or more ingoing storage containers.

Other variations and advantages will become apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the invention will now be described, by way of example only, and with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an example of a storage system comprising a plurality of freestanding stacks of storage containers; Figure 2 is a schematic illustration of an example of a load handling device suitable for use in the system of Figure 1; Figures 3a to 3g are a sequence showing the load handling device of Figure 1 operating to extract an outgoing container from a stack of storage containers; Figure 4 is perspective view of the load handling device of Figure 2 collecting storage containers from a pick-up point; Figure 5 is perspective view of the load handling device of Figure 2 collecting storage containers from a transport vehicle; Figure 6 is a perspective view of a further example of a storage system comprising a plurality of freestanding stacks of storage containers; Figure 7 is a schematic illustration of a further example of a load handling device suitable for use in the systems of Figures 1 and 6; Figures 8a to 8b are a sequence showing the load handling device of Figure 7 operating to extract an outgoing container from a stack of storage containers; Figures 9a to 9c are a sequence showing the load handling device of Figure 7 operating to extract an outgoing stack of storage containers from a larger stack of storage containers; Figures 103 to 10b are a sequence showing the load handling device of Figure 7 operating to change the order of the storage containers in a stack; Figures lla to 11g are a sequence showing the load handling device of Figure 7 operating to unstack a stack of storage containers at a drop-off point; Figures 12, 13 and 14 are schematic illustrations of yet further examples of load handling devices suitable for use in the systems of Figures 1 and 6; Figure 15 is a perspective view of a specific example of load handling device suitable for use in the systems of Figures 1 and 6; and Figures 16 and 17 a perspective views of a yet example of a storage system comprising a plurality of freestanding stacks of storage containers.

Detailed description

The following embodiments represent preferred examples of how the invention may be practiced, but they are not necessarily the only examples of how this could be achieved. These examples are described in sufficient detail to enable those skilled in the art to practice the invention. Other examples may be utilised and structural changes may be made without departing from the scope of the invention as defined in the appended claims. Moreover, direction references and any other terms having an implied orientation are given by way of example to aid the reader's understanding of the particular examples described herein. They should not be read to be requirements or limitations, particularly as to the position, orientation, or use of the invention unless specifically set forth in the appended claims. Similarly, connection references (e.g., attached, coupled, connected, joined, secured, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other, unless specifically set forth in the appended claims. Similarly, wording such as "movement in the n-direction" and any comparable wording, where n is one of x, y or z, is intended to mean movement substantially along or parallel to the n-axis, in either direction (i.e., towards the positive end of the n-axis or towards the negative end of the n-axis).

Figure 1 illustrates an example of a storage system 100, the storage system comprising a plurality of freestanding stacks 102 of storage containers 101 stored in a workspace. Each storage container 101 typically holds a plurality of product items (not shown), and the product items within a storage container 101 may be identical, or may be of different product types depending on the application. The stackable storage containers 101, known as bins, are stacked on top of one another to form the stacks 102 that are freestanding on a floor or surface 103 of the workspace. It may be preferable for the storage containers 101 to be arranged to interlock or at partially nest with one another to ensure that the storage containers 101 are stable when stacked.

The storage system 100 then further comprises load handling devices 110 for lifting and moving the storage containers 101 in order to deposit storage containers in and retrieve storage containers from the stacks 102. In particular, the load handling devices 110 are arranged to be able to laterally insert storage containers 101 into a stack 102 and laterally extract storage containers 101 from a stack 102, rather than merely adding storage containers 101 to or removing storage containers 101 from the top of the stack 102. The load handling devices 110 are therefore arranged to move along the floor 103 around the stacks 102 from where the load handling devices 110 can access the side of any exposed stack 102.

As shown in Figure 1, the stacks 102 are arranged in rows, with multiple rows being grouped together to form separate blocks or sections 104 of stacks 102 and with each block 104 of stacks 102 being at least partially bounded by intersecting aisles 105. The aisles 105 between the blocks 104 are therefore defined by the separation between adjacent blocks 104 of stacks 102 with the separation being sufficient to allow the load handling devices 110 to move along the aisles 105 between the blocks 104 in order to access the outermost stacks 102 of the block 104.

Figure 2 is a schematic illustration of an example of a load handling device 110 suitable for lifting and moving storage containers 101 stacked in a storage system 100 such as that shown in Figure 1. In the example of Figure 2, the load handling device 110 comprises a body 111 mounted on movement means 112a, 112b that are arranged to allow the load handling device 110 to move around a surface beneath the load handling device 110. The load handling device 110 then further comprises a container displacement device 113 mounted to the body 111 and a separate, container lifting device 114 that is also mounted to the body 111. The container displacement device 113 is arranged to move a storage container 101 supported on the container displacement device 113 vertically and horizontally relative to the body 111, whilst the container lifting device 114 is arranged to move one or more stacked storage containers 101 supported thereon vertically relative to the body 111.

The container displacement device 113 is arranged to move a storage container 101 supported on the container displacement device 113 vertically and horizontally relative to the body 111 in order to laterally extract a storage container 101 from a stack 102 and to laterally insert a storage container 101 into a stack 102. The container lifting device 114 is then arranged to move one or more stacked storage containers 101 supported thereon vertically relative to the body 111 in order to raise and lower the one or more stacked storage containers 101. Coordinating the operation of the container displacement device 113 and the container lifting device 114 therefore enables the load handling device 110 to laterally insert storage containers 101 in to and extract storage containers 101 from a stack 102.

The load handling device 110 is configured to operate as an automated or autonomous vehicle, e.g. an automated guided vehicle (AGV) which is capable of following fixed routes, or an autonomous mobile robot (AMR) which is capable of planning its own routes. The load handling device 110 may therefore comprise any components necessary in order to allow the load handling device 110 to function as an automated or autonomous vehicle, such as motors, batteries, sensors, memory, processors, transceivers etc. In particular, the load handling device 110 may be arranged to communicate with a central controller of the storage system 100 in order to receive and respond to instructions to deposit storage containers in and retrieve storage containers from the stacks 102.

In the example of Figure 2, the movement means 112a, 112b comprises a set of forward wheels 112a and a set of rear wheels 112b. In particular, the load handling device 110 comprises two separate arms 118a, 118b at each side of the body 111 that extend forward (F) away from the body 111, with a forward wheel 112a mounted at the distal end of each of the arms 118a, 118b. Consequently, the forward wheels 112a are indirectly mounted to the body 111, and are disposed in front of the body 111. The rear wheels 112b are then directly mounted at opposite sides at the rear (R) of the load handling device 110. Such an arrangement assists in stabilizing the load handling device 110 when carrying storage containers 101. In this example, the forward wheels 112a are caster wheels or any other form of multidirectional wheel, whilst the second wheels 112b are differentially driven wheels. In an alternative arrangement, the movement means 112a, 112b could equally comprise any other movement means such as continuous tracks or rollers.

The container displacement device 113 comprises a first container support assembly 115 arranged to support a storage container 101, a first lifting mechanism (not shown) arranged to move the first container support assembly 115 vertically relative to the body 111 of the load handling device 110, and a transfer mechanism (not shown) arranged to move the storage containers supported on the first container support assembly 115 horizontally relative to the body 111 of the load handling device 110. The first lifting mechanism moves the first container support assembly 115, and any storage container 101 supported thereon, vertically between a first upper position U1 and a first lower position L1. The transfer mechanism then moves a storage container 101 supported on the first container support assembly 115 horizontally between a first, forward position and a second, rearward position.

In the example of Figure 2, the transfer mechanism is arranged to move the first container support assembly 115, and any storage container 101 supported thereon, horizontally between the forward position and the rearward position. The first lifting mechanism and the transfer mechanism may then be separate mechanisms or may be a single combined mechanism that is capable of moving the first container support assembly 115 both vertically and horizontally.

The container lifting device 114 then comprises a second container support assembly 116 and a second lifting mechanism (not shown) that is arranged to move the second container support assembly 116 vertically relative to the body 111 of the load handling device 110. The second lifting mechanism moves the second container support assembly 116, and any storage containers 101 supported thereon, vertically between a second upper position U2 and a second lower position L2.

In the example illustrated in Figure 2, the second upper position U2 is higher than the first upper position U1. This allows the container lifting device 114 to raise a storage container 101 supported thereon away from another storage container 101 that is to be inserted in to or extracted from the stack 102 by the container displacement device 113. The lower positions Ul, U2 of both the container displacement device 113 and the container lifting device 114 may then be approximately the same, such that both the container displacement device 113 and the container lifting device 114 can lift storage containers from and lower storage containers to a floor or surface beneath the load handling device 110.

In the example of Figure 2, the second container support assembly 116 can move vertically past the first container support assembly 115. In particular, the second container support assembly 116 can move vertically past the first container support assembly 115 when the first container support assembly 115 is in the rearward position in order to allow the second container support assembly 116 to lower any storage containers 101 supported thereon to the floor without colliding with the first container support assembly 115. To do so, the first container support assembly 115 and the second container support assembly 116 are independently mounted to the body 111 of the load handling device 110. In a preferred arrangement, the first container support assembly 115 is movably mounted to a first vertical track (not shown) provided on the body 111 and the second container support assembly 116 is movably mounted to a separate, second vertical track (not shown) provided on the body 111, with the first vertical track and the second vertical track being horizontally spaced (i.e. separated in the horizontal direction) from one another. In particular, the first vertical track is spaced rearward relative to the second vertical track (i.e. is closer to the rear (R) of the body 111 than the second vertical track).

The load handling device 110 is arranged such that a storage container 101 supported on the first container support assembly 115 does not horizontally overlap with any storage containers 101 supported on the second container support assembly 116 when the first container support assembly 115 is in the rearward position. This ensures that any storage containers 101 supported on the second container support assembly 116 do not collide with any storage containers 101 supported on the first container support assembly 115 when the second container support assembly 116 moves vertically past the first container support assembly 115. In a preferred arrangement, the load handling device is arranged such that any storage containers 101 supported on the second container support assembly 116 are horizontally aligned with a storage container 101 supported on the first container support assembly 115 when the first container support assembly 115 is in the forward position. Such an arrangement provides that the second container lifting device 114 can raise one or more storage containers 101 supported on the second container support assembly 116 away from a storage container 101 supported on the first container support assembly 115 and, conversely, lower one or more storage containers 101 supported on the second container support assembly 116 on to a storage container 101 supported on the first container support assembly 115.

The container displacement device 113 is arranged to engage a storage container 101, lift the engaged storage container 101, and thereby also lift any storage containers 110 supported by (i.e. stacked on top of) the engaged storage container 101. The container displacement device 113 is then also arranged to lower and disengage the storage container 101. To do so, the first container support assembly 115 of the container displacement device 113 may be arranged to extend forward (F) from the body 111 and under at least a portion of a storage container 101 that is immediately forward (F) of the body 111. Moving the first container support assembly 115 vertically upwards then causes the first container support assembly 115 to engage an underside of the storage container 101 in order to lift the storage container 101. Conversely, the first container support assembly 113 can then disengage the underside of the storage container 101 when moved vertically downward.

The container displacement device 113 is also arranged to move a storage container 101 supported thereon horizontally relative to the body 111 between a forward position and a rearward position. To do so, the first container support assembly 115 may be arranged to move horizontally between a forward position in which the first container support assembly 115 extends forward (F) from the body 111 and a rearward position in which the first container support assembly 115 extends at least partially rearward (R) from the body 111. Any storage container 101 supported on the first container support assembly 115 then moves with the first container support assembly 115. To do so, the transfer mechanism of the first container lifting device 113 may comprise a linear actuator arranged to move the first container support assembly 115 between the forward position and the rearward position. For example, the transfer mechanism may comprise a rack and pinion mechanism that connects the first container support assembly 115 to the first lifting mechanism.

In the example of Figure 2, the first container support assembly 115 comprises a pair of first support members or forks 115a, 115b that extend forward from the body 111 of the load handling device 110 such that they can each be located underneath a cooperating feature of a storage container 101.

Raising the first support members 115a, 115b using the first lifting mechanism then causes the first support members 115a, 115b to engage the respective cooperating feature such that the storage container 101 is supported on the first support members 115a, 115b. Further vertical movement of the first support members 115a, 115b then causes the storage container to be lifted by the first container lifting device 113. In particular, in the example of Figure 1, each storage container 101 is provided with the cooperating features that comprise a pair of flanges that project out from opposing sides of the storage container 101. Each of the first support members 115a, 115b can therefore be located on opposing sides of the storage container 101, beneath a corresponding flange, and raised up such that the first support member 115a, 115b contacts the underside of the corresponding flange.

Once a storage container 101 has been lifted by the first lifting mechanism, the transfer mechanism then moves the first support members 115a, 115b, and the storage container 101 supported thereon, horizontally between a forward position and a rearward position. In the example of Figure 2, the body 111 of the load handling device 110 further comprises an opening 117 arranged to allow at least a portion of a storage container 101 supported on the first container support assembly 115 to pass at least partially through the body 111 when moving between the forward position, in which the first container support assembly 115 extends forward (F) from the body 111, and the rearward position, in which the first container support assembly 115 extends at least partially rearward (R) from the body 111.

The container lifting device 114 is arranged to engage a storage container 101, lift the engaged storage container 101, and thereby also lift any storage containers 101 supported by (i.e. stacked on top of the) engaged storage container 101. The container lifting device 114 is then also arranged to lower and disengage the storage container 101. To do so, the second container support assembly 116 may be arranged to extend forward from the body 111 and under at least a portion of a storage container that is immediately forward of the body 111. Moving the second container support assembly 116 vertically upwards then causes the second container support assembly 116 to engage an underside of the storage container 101 in order to lift the storage container 101. Conversely, the second container support assembly 116 can then disengage the underside of the storage container 101 when moved vertically downward.

In the example of Figure 2, the second container support assembly 116 comprises a pair of second support members or forks 116a, 116b that extend forward from the body 111 of the load handling device 110 such that they can each be located underneath a cooperating feature of a storage container 101. Raising the second support members 116a, 116b using the second lifting mechanism then causes the second support members 116a, 116b to engage the respective cooperating feature such that the storage container 101 is supported on the second support members 116a, 116b. Further vertical movement of the second support members 116a, 116b then causes the storage container 101 to be lifted by the container lifting device 114. As described above, in the example of Figure 1, each storage container 101 is provided with the cooperating features that comprise a pair of flanges that project out from opposing sides of the storage container 101. Each of the second support members 116a, 116b can therefore be located on opposing sides of the storage container 101, beneath a corresponding flange, and raised up such that the second support member 116a, 116b contacts the underside of the corresponding flange.

Figures 3a to 3g then illustrate a sequence showing the load handling device 110 of Figure 2 implementing an insertion operation in which an ingoing storage container 101a is inserted laterally into a destination stack 102. Figure 3a shows the load handling device 110 transporting an ingoing storage container 1013 and approaching a destination stack 102 to which the load handling device 110 has been instructed to insert the ingoing storage container 101a In this regard, the load handling device 110 would typically be under the control of a central control facility (not shown) of the storage system 100, with the central control facility being responsible for controlling and coordinating the movement and operation of the load handling devices 110 of the system 100. The central control facility may therefore provide the instructions to the load handling device 100, with these instructions identifying the destination stack 102. For example, the central control facility may store the coordinates of every storage container 101 in the system 100, and details of the contents of each storage container 101, and may therefore be able to determine the optimal storage location for an ingoing storage container. Expanding upon this example, the central control facility may store the coordinates of each storage container using the horizontal X, Y position of the relevant stack in the workspace and the vertical position of the storage container within the stack In Figure 3a, the ingoing storage container 1013 is supported on the container displacement device 113 of the load handling device 110, with the first container support assembly 115 in the forward position. The first container support assembly 115 is also raised above the first lower position Ll such that the ingoing storage container 101a is supported on the first container support assembly 115 and is vertically separated from the floor on which the load handling device 110 is moving.

Prior to this, the load handling device 110 will have obtained the ingoing storage container 101a from another location. For example, the load handling device 110 may have obtained the ingoing storage container 101a from another stack in the system or from an inventory handling station, such as a pick or decant station, by lifting the ingoing storage container 101a from a pick-up point using the first container lifting device 113. By way of example, Figure 4 illustrates load handling devices 110 collecting storage containers 101 from a pick-up point 107 at an inventory handling station 106 of the storage system 100. In this example, the load handling devices 110 use the container displacement device 113 to laterally extract a storage container 101 from a pick-up point 107. By way of further example, Figure 5 illustrates a load handling device 110 collecting a storage container 101 from a transport vehicle (T) that has transported stacks 102 of storage containers 101. In this example, the load handling device 110 laterally extracts storage containers 101 from the stacks 102 that are supported on the floor of the transport vehicle (T).

Whilst travelling to the destination stack 102, the load handling device 110 holds the ingoing storage container 101a in the forward position in order to minimise the space taken up by the load handling device 110. Then, upon arriving in the vicinity of the destination stack 102, the load handling device 110 uses the transfer mechanism of the container displacement device 113 to move the ingoing storage container 1013 from the forward position to the rearward position, through the opening 117 in the body 111, in order to clear the space immediately in front of the body 111 of the load handling device 110, as shown in Figure 3b.

The load handling device 110 then uses the container lifting device 114 to lower the second container support assembly 116 until the second support members 116a, 116b are lower than the cooperating features of the bottom storage container 101b of the destination stack 102. The second container support assembly 116 may then be in the second lower position L2. The load handling device 110 then moves forward until the destination stack 102 is immediately in front of the body 111 of the load handling device 110 and the second support members 116a, 116b are located underneath the cooperating features of the bottom storage container 101b, as shown in Figure 3c. In this position, the arms 118a, 118b on which the forward wheels 112a are mounted are disposed on either side of the destination stack 102.

The load handling device 110 then uses the second container lifting mechanism to raise the second container support assembly 116 such that the second support members 116a, 116b engage the cooperating features of the bottom storage container 101b of the destination stack 102 and lift the bottom storage container 101b upwards away from the floor on which the destination stack 102 has been resting. In doing so, the container lifting device 114 lifts the entirety of the destination stack 102 away from the floor. The container lifting device 114 then continues to lift the supported storage containers (i.e. the bottom storage container 101b and the storage containers that are stacked on the bottom storage container 101b) to a height that is sufficient for another storage container to be inserted underneath, as shown in Figure 3d.

The load handling device 110 then uses the transfer mechanism of the container displacement device 113 to move the ingoing storage container 101a from the rearward position to the forward position, through the opening 117 in the body 111. At this stage, the ingoing storage container 101a is supported on the first container support members 115a, 115b and is horizontally aligned beneath the storage containers that have been lifted by the container lifting device 114 and are therefore supported on the second container support members 116a, 116b (i.e. the bottom storage container 101b of the destination stack 102 and the storage containers that are stacked on the bottom storage container 101b), as shown in Figure 3e.

The load handling device 110 then uses the container displacement device 113 to lower the ingoing storage container 101a until the ingoing storage container 1013 is resting upon the floor and the first container support members 115a, 115b have disengaged and are lower than the cooperating features of the ingoing storage container 101a. The first container support assembly 115 may then be in the first lower position L1. The load handling device 110 then uses the container lifting device 114 to lower the storage containers that are supported on the second container support members 116a, 116b until the bottom storage container 101b of the supported storage containers is resting upon the ingoing storage container 101a, and the second container support members 116a, 116b have disengaged and are lower than the cooperating features of the bottom storage container 101b of the supported storage containers.

At this stage, the storage containers that initially made up the destination stack 102 are supported on the ingoing storage container 101a such that the ingoing storage container 1013 has been added to the destination stack 102 thereby increasing the final size of the destination stack 102, as shown in Figure 3f. The load handling device 110 then moves backward until the load handling device 110 is clear of the destination stack 102, as shown in Figure 3g. From this position, the load handling device 110 can then move away from the destination stack 102 and proceed to implement a new operation.

To implement an extraction operation in which an outgoing storage container is extracted laterally from a source stack 102 the load handling device 110 essentially reverses the above described insertion operation. Consequently, an exemplary extraction operation will be described with reference to Figures 3a to 3g. In order to extract an outgoing storage container 101a from a source stack 102 from which the load handling device 110 has been instructed to extract the outgoing storage container 101a, the load handling device 110 travels to the source stack 102 with the first container support assembly 115 in the forward (F) position in order to minimise the space taken up by the load handling device 110.

Prior to arriving at the source stack 102, the load handling device 110 uses the container displacement device 113 to ensure that the first support members 115a, 115b of the first container support assembly 115 are lower than the cooperating features of the outgoing storage container 101b, i.e. the bottom storage container 101b of the source stack 102. The first container support assembly 115 may then be in the first lower position L1. The load handling device 110 also uses the container lifting device 114 to ensure that the second support members 116a, 116b of the second container support assembly 116 are above the cooperating features of the bottom storage container 101a of the source stack 102 and below the cooperating features of the second from bottom storage container 101b (i.e. the storage container 101b immediately above the bottom storage container 1013), as shown in Figure 3g. The load handling device 110 may be configured to maintain the first container support assembly 115 and the second container support assembly 116 in these positions whenever they are not supporting any storage containers, i.e. as default positions. Alternatively, the load handling device 110 may be configured to only move the first container support assembly 115 and the second container support assembly 116 to these positions when required, i.e. in preparation for or during the implementation of an operation.

The load handling device 110 then moves forward until the source stack 102 is immediately in front of the body 111 of the load handling device 110, with the first support members 115 located directly underneath the cooperating features of the bottom, outgoing storage container 101a and with the second support members 116 located directly underneath the cooperating features of the second from bottom storage container 101b, as shown in Figure 3f. In this position, the arms 118a, 118b on which the forward wheels 112a are mounted are disposed on either side of the destination stack 102.

The load handling device 110 then uses the second container lifting mechanism of the container lifting device 114 to raise the second container support assembly 116 such that the second support members 116a, 116b engage the cooperating features of the second from bottom storage container 101b of the source stack 102 and lift the second from bottom storage container 1016 upwards away from the outgoing storage container 101a on which the second from bottom storage container 101b has been resting. In doing so, the container lifting device 114 lifts the rest of the source stack 102 away from the outgoing storage container 101a, as shown in Figure 3e. The container lifting device 114 then continues to lift the supported storage containers (i.e. the second from bottom storage container 101b and the storage containers stacked thereon) to a height that is sufficient for the outgoing storage container 101a to be raised up and extracted from beneath. The second container support assembly 116 of the container lifting device 114 may then be in the second upper position U2.

The load handling device 110 then uses the first container lifting mechanism of the container displacement device 113 to raise the first container support assembly 115 such that the first support members 115a, 115b engage the cooperating features of the outgoing storage container 101a and lift the outgoing storage container 101a upwards away from the floor on which the outgoing storage container 101a has been resting, as shown in Figure 3e.

The load handling device 110 then uses the transfer mechanism of the container displacement device 113 to move the outgoing storage container 101a from the forward position to the rearward position, through the opening 117 in the body 111. At this stage, the outgoing storage container 101a is supported on the first container support members 115a, 115b and is horizontally offset relative to the storage containers that are supported on the second container support members 116a, 116b, as shown in Figure 3d.

The load handling device 110 then uses second container lifting mechanism of the container lifting device 114 to lower the supported storage containers until the bottom storage container 101b of the supported storage containers is resting upon the floor and the second container support members 116a, 116b have disengaged and are lower than the cooperating features of the bottom storage container 101b of the supported storage containers, as shown in Figure 3c. The second container support assembly 116 may then be in the second lower position L2. At this stage, the outgoing storage container 101a has been removed from the source stack 102, thereby decreasing the final size of the source stack 102, and the remaining storage containers of the source stack 102 are supported on the floor (i.e. with the storage container 101b that was initially second from bottom now being at the bottom of the final source stack 102).

The load handling device 110 then moves backward until the load handling device 110 is clear of the source stack 102, as shown in Figure 3b. The load handling device 110 then uses the transfer mechanism of the container displacement device 113 to move the outgoing storage container 1103 from the rearward position to the forward position, through the opening 117 in the body 110, as shown in Figure 3a. From this position, the load handling device 110 can then move away from the source stack 102, with the outgoing storage container 101a, in order to implement a further operation.

For example, such a further operation may involve delivering the outgoing storage container 101a to another stack in the system or to a drop-off point at an inventory handling station, such as a pick or decant station. By way of example, the load handling device 110 could deliver an outgoing storage container 101a to a drop-off point 108 at an inventory handling station 106 of the storage system 100, as illustrated in Figure 4. By way of further example, the load handling device 110 could deliver an outgoing storage container 110 to a transport vehicle (T) that is being used to transport stacks 102 of storage containers 101, in a manner equivalent to that described above in relation to Figure 5. In this case, the load handling device 110 laterally inserts storage containers 110 into stacks 102 that are supported on the floor of the transport vehicle (T).

Figure 6 illustrates a further example a storage system 100 comprising a plurality of freestanding stacks 102 of storage containers 101 stored in a workspace and load handling devices 120 for lifting and moving the storage containers 101 in order to deposit storage containers in and retrieve storage containers from the stacks 102. The load handling devices 120 are arranged to move along the floor around the stacks 102 and to be able to insert and extract storage containers 101 laterally from a stack 102.

As with the example of Figure 1, the system of Figure 6 comprises stacks 102 arranged in rows, with multiple rows being grouped together to form separate blocks or sections 104 of stacks 102 and with each block 104 of stacks 102 being at least partially bounded by intersecting aisles 105. The aisles 105 between the blocks 104 are defined by the separation between adjacent blocks 104 of stacks 102 with the separation being sufficient to allow the load handling devices 120 to move along the aisles 105 between the blocks 104 in order to access the outermost stacks 102 of each block 104.

As described above, Figure 1 illustrates an arrangement in which each block 104 of stacks 102 consists of just two rows of stacks 102. Such an arrangement provides that all stacks 102 in a block 104 can be immediately accessed by a load handling device from one of the bounding aisles 105. In contrast, Figure 6 illustrates an alternative arrangement comprising blocks 104 of various formations. Specifically, the stacks 102 located on the right-hand side of the workspace are arranged in blocks 104a that each consists of two rows of stacks 102, thereby providing immediate access to the stacks 102 in these blocks 104a. The stacks 102 located on the left-hand side of the workspace are then arranged in a single large block 104b consisting of thirty five rows of stacks 102. Whilst a block 104 of stacks 102 consisting of more than two rows will require stacks 102 to be moved in order to reach those stacks 102 that are not at the edge of the block 104, reducing the overall accessibility, such a formation has a higher storage density. The block 104b on the left-hand side would therefore be ideal for storing items that do not need to be accessed quickly and/or with high frequency, such as additional stock, slow moving items etc. The stacks 102 located in the centre of the workspace are then arranged in blocks 104c that consist of four rows of stacks 102. Such a formation provides a higher storage density than a block 104c with fewer rows whilst still providing that the stacks 102 that are not at the edge of the block 104c can be accessed relatively quickly.

Figure 7 is a schematic illustration of a further example of a load handling device 120 suitable for lifting and moving storage containers 101 stacked in a storage system 100 such as those shown in Figures 1 and 6. The load handling device 120 of Figure 7 is similar to the load handling device 110 of Figure 2, and corresponding reference numerals have therefore been used for like or corresponding parts or features. In particular, the general arrangement and functionality of the load handling device 120 of Figure 7 is largely the same as the load handling device 110 of Figure 2. However, whilst the load handling device 110 of Figure 2 is arranged to be able to extract and insert a single storage container 101 at the bottom of a stack 102 of storage containers 101, the load handling device 120 of Figure 7 is arranged to be able to extract and insert one or more storage containers 101 at any position within a stack 102 of storage containers 101.

Consequently, whilst the body 111 of the load handling device 110 of Figure 2 is tall enough to allow the bottom and second from bottom storage containers 101 of a stack 102 to be lifted up by the load handling device 110, and the opening 117 in the body 111 is tall enough to allow a single storage container 101 to pass through the opening 117, the body 121 of the load handling device 120 of Figure 7 is tall enough to allow any of the storage containers 101 in a stack 102 to be lifted up by the load handling device 110, and the opening 127 in the body 121 is tall enough to allow all of the storage containers 101 in a stack 102 to pass through the opening 127.

As a further consequence, the container displacement device 123 and the container lifting device 124 of the load handling device 120 of Figure 7 are arranged to move storage containers 101 vertically to any height within the height of a stack 102. To do so, the first lifting mechanism (not shown) of the container displacement device 123 is arranged to move the first container support assembly 125, and any storage containers 101 supported thereon, vertically between a first upper position Ul and a first lower position Ll, wherein the first upper position U1 is adjacent to the top of the opening 127.

Correspondingly, the second lifting mechanism (not shown) of the container lifting device 124 is arranged to move the second container support assembly 126, and any storage containers 101 supported thereon, vertically between a second upper position U2 and a second lower position L2, wherein the second upper position U2 is also adjacent to the top of the opening 127. The lower positions U1, U2 of both the container displacement device 123 and the container lifting device 124 may also be approximately the same, such that both the container displacement device 123 and the container lifting device 124 can lift storage containers from and lower storage containers to the floor.

Figures 8a and 8b then illustrate a sequence showing the load handling device 120 of Figure 7 implementing an extraction operation in which an outgoing storage container 101a is extracted laterally from a source stack 102. In order to extract an outgoing storage container 101a from a source stack 102 from which the load handling device 120 has been instructed to extract the outgoing storage container 101a, the load handling device 120 travels to the source stack 102 with the first container support assembly 125 in the forward position in order to minimise the space taken up by the load handling device 120.

Prior to arriving at the source stack 102, the load handling device 120 uses the first container lifting mechanism to ensure that the first support members 125a, 125b of the first container support assembly 125 are lower than the cooperating features of the outgoing storage container 101a of the source stack 102. In the example shown in Figures 8a and 8b, the load handling device 120 has been instructed to extract a storage container 101 from the middle of the source stack 102. Consequently, the first support members 125a, 125b are below the cooperating features of the outgoing storage container 1013 and above the cooperating features of the storage container 101c that is immediately below the outgoing storage container 1013 in the source stack 102. The first container support assembly 125 is therefore between the first lower position Ll and the first upper position Ul.

The load handling device 120 also uses the second container lifting mechanism of the second container lifting device 126 to ensure that the second support members 126a, 126b of the second container support assembly 126 are above the cooperating features of the outgoing storage container 1013 and below the cooperating features of the storage container 101b that is immediately above the outgoing storage container 101a in the source stack 102 (i.e. the storage container stacked/borne directly upon the outgoing storage container 101a). Consequently, the second container support assembly 126 is located between the second lower position L2 and the second upper position U2, and above the first container support assembly 125.

The load handling device 120 then moves forward until the source stack 102 is immediately in front of the body 121 of the load handling device 120, with the first support members 125 located directly underneath the cooperating features of the outgoing storage container 101a and with the second support members 126 located directly underneath the cooperating features of the storage container 101b stacked upon the outgoing storage container 101a.

The load handling device 120 then uses the second container lifting mechanism of the container lifting device 124 to raise the second container support assembly 126 such that the second support members 126a, 126b engage the cooperating features of the storage container 101b stacked upon the outgoing storage container 1013 in the source stack 102 and lift the storage container 101b upwards away from the outgoing storage container 101a. In doing so, the second container lifting device 124 lifts the rest of the source stack 102 away from the outgoing storage container 101a. The second container lifting device 124 then continues to lift the supported storage containers (i.e. storage container 101b and the storage containers stacked thereon) to a height that is sufficient for the outgoing storage container 101a to be raised up and extracted from beneath.

The load handling device 120 then uses the first container lifting mechanism of the container displacement device 123 to raise the first container support assembly 125 such that the first support members 125a, 125b engage the cooperating features of the outgoing storage container 101a and lift the outgoing storage container 101a upwards away from the storage container 101c on which the outgoing storage container 101a has been resting, as shown in Figure 8a. The storage containers 101 of the stack 102 that are below the outgoing storage container 101a remain resting on the surface beneath the stack 102.

The load handling device 120 then uses the transfer mechanism of the container displacement device 123 to move the outgoing storage container 101a from the forward position to the rearward position, through the opening 127 in the body 121. The outgoing storage container 101a is then supported on the first container support members 125a, 125b and horizontally offset relative to the storage containers 101 that are supported on the second container support members 126a, 126b, as shown in Figure 8b.

The load handling device 120 then uses second container lifting mechanism of the container lifting device 124 to lower the lifted portion of the stack (i.e. the storage containers supported thereon) until the bottom storage container 101b of the supported storage containers is resting upon the top storage container 101c of those storage containers 101 that are resting on the floor and the second container support members 126a, 126b have disengaged and are lower than the cooperating features of the bottom storage container 101b of the supported storage containers. At this stage, the remaining storage containers of the source stack 102 are supported on the floor, with the outgoing storage container 101a having been removed from the source stack 102, thereby decreasing the size of the final source stack 102.

The load handling device 120 then moves backward until the load handling device 120 is clear of the source stack 102. The load handling device 120 then uses the transfer mechanism of the container displacement device 123 to move the outgoing storage container 1013 from the rearward position to the forward position, through the opening 127 in the body 121. From this position, the load handling device 120 can then move away from the source stack 102, with the outgoing storage container 101a, in order to implement a further operation. For example, such a further operation may involve delivering the outgoing storage container 101a to another stack in the system or to a drop-off point at an inventory handling station, such as a pick or decant station.

The load handling device 120 can also reverse the above described extraction operation in order to implement an insertion operation in which an ingoing storage container 101a is inserted laterally into a destination stack 102.

In addition to extracting and inserting a single storage container 101, the load handling device 120 of Figure 7 can also be used to extract and insert a plurality of stacked storage containers 101 in a single operation. In other words, the load handling device 120 can be used to extract an outgoing stack 102a comprising a plurality of stacked storage containers 101 laterally from within a source stack 102 and to insert an ingoing stack 102a comprising a plurality of stacked storage containers 101 laterally into a destination stack 102.

For an operation involving the extraction of a plurality of stacked storage containers 101 from within a source stack 102, the outgoing stack 102a comprises a portion of the initial source stack 102. In particular, after completion of the extraction operation, the final source stack 102 then comprises those storage containers 101 that made up the initial source stack 102 less those storage containers 101 that made up the outgoing stack 102a. The outgoing stack 102a can comprise plurality of storage containers 101 from the bottom of the source stack 102, a plurality of the storage containers 101 from the top of the source stack 102, or a plurality of storage containers 101 from the middle of the source stack 102 (i.e. that does not include either the bottom storage container or the top storage container of the source stack 102).

For an operation involving the insertion of a plurality of stacked storage containers 101 into a destination stack 102, the ingoing stack 102a becomes a portion of the final destination stack 102. In particular, after completion of the insertion operation, the final destination stack 102 then comprises both those storage containers 101 that made up the initial destination stack 102 and those storage containers 101 that made up the ingoing stack 102a. The ingoing stack 102a can be inserted at the bottom of the destination stack 102 (i.e. below the bottom storage container of the initial destination stack 102), at the top of the destination stack 102 (i.e. above the top storage container of the initial destination stack 102), or in the middle of the destination stack 102 (i.e. anywhere between the bottom storage container and the top storage container of the destination stack 102).

Figures 9a to 9c then illustrate a sequence showing the load handling device 120 of Figure 7 implementing an extraction operation in which an outgoing stack 102a, comprising a plurality of stacked storage containers 101, is extracted laterally from within a source stack 102. In order to extract an outgoing stack 102a from a source stack 102 from which the load handling device 120 has been instructed to extract the outgoing stack 102a, the load handling device 120 travels to the source stack 102 with the first container support assembly 125 in the forward position in order to minimise the space taken up by the load handling device 120.

Prior to arriving at the source stack 102, the load handling device 120 uses the first container lifting mechanism of the container displacement device 123 to ensure that the first support members 125a, 125b of the first container support assembly 125 are lower than the cooperating features of the bottom storage container 101a of the outgoing stack 102a. In the example shown in Figures 9a to 9c, the load handling device 120 has been instructed to extract an outgoing stack 102a from the middle of the source stack 102. Consequently, the first support members 125a, 125b are below the cooperating features of the bottom storage container 101a of the outgoing stack 102a and above the cooperating features of the storage container 101c that is immediately below the outgoing stack 102a in the source stack 102. The first container support assembly 125 is therefore between the first lower position Ll and the first upper position Ul.

The load handling device 120 also uses the second container lifting mechanism of the container lifting device 124 to ensure that the second support members 126a, 126b of the second container support assembly 126 are above the cooperating features of the top storage container of the outgoing stack 102a and below the cooperating features of the storage container 101b that is immediately above the outgoing stack 102a in the source stack 102. Consequently, the second container support assembly 126 is located between the second lower position L2 and the second upper position U2, and above the first container support assembly 125.

The load handling device 120 then moves forward until the source stack 102 is immediately in front of the body 121 of the load handling device 120, with the first support members 125a, 125b located directly underneath the cooperating features of the bottom storage container 102a of outgoing stack 102a and with the second support members 126a, 126b located directly underneath the cooperating features of the storage container 101b stacked upon the outgoing stack 102a.

The load handling device 120 then uses the second container lifting mechanism of the container lifting device 124 to raise the second container support assembly 126 such that the second support members 126a, 126b engage the cooperating features of the storage container 101b stacked upon the outgoing stack 102a in the source stack 102 and lift the storage container 101b upwards away from the outgoing stack 102a. In doing so, the container lifting device 124 lifts the portion of the source stack 102 that is above the outgoing stack 1023 away from the outgoing stack 102a. The second container lifting device 124 then continues to lift the lifted the portion of the source stack 102 (i.e. storage container 101b and the storage containers stacked thereon) to a height that is sufficient for the outgoing stack 102a to be raised up and extracted from beneath.

The load handling device 120 then uses the first container lifting mechanism of the container displacement device 123 to raise the first container support assembly 125 such that the first support members 125a, 125b engage the cooperating features of the bottom storage container 101a of the outgoing stack 102a and lift the outgoing stack 102a upwards away from the storage container 101c on which the bottom storage container 101a of the outgoing stack 102 has been resting, as shown in Figure 9a. The portion of the source stack 102 that is below the outgoing stack 102a remains resting on the surface beneath the stack 102.

The load handling device 120 then uses the transfer mechanism of the container displacement device 123 to move the outgoing stack 102a from the forward position to the rearward position, through the opening 127 in the body 121. At this stage, the outgoing stack 102a is supported on the first container support members 125a, 125b and is horizontally offset relative to both the storage containers that are supported on the second container support members 126a, 126b and the storage containers that are resting on the floor, as shown in Figure 9b.

The load handling device 120 then uses second container lifting mechanism of the container lifting device 124 to lower the lifted portion of the source stack 102 until the bottom storage container 101b of the lifted portion of the source stack 102 is resting upon the top storage container 101c of those storage containers 101 that are resting on the floor and the second container support members 126a, 126b have disengaged and are lower than the cooperating features of the bottom storage container 101b of the lifted portion of the source stack 102, as shown in Figure 9c. At this stage, the remaining storage containers of the source stack 102 are supported on the floor, with the outgoing stack 102a having been removed from the source stack 102 thereby decreasing the final size of the source stack 102.

The load handling device 120 then moves backward until the load handling device 120 is clear of the source stack 102. The load handling device 120 then uses the transfer mechanism of the container displacement device 123 to move the outgoing stack 102a from the rearward position to the forward position, through the opening 127 in the body 121. From this position, the load handling device 120 can then move away from the source stack 102, with the outgoing stack 102a, in order to implement a further operation. For example, such a further operation may involve delivering the outgoing stack 102a to another stack in the system or to a drop-off point at an inventory handling station, such as a pick or decant station.

The load handling device 120 can also reverse the above described extraction operation in order to implement an insertion operation in which an ingoing stack 102a, comprising a plurality of stacked storage containers 101, is inserted laterally into a destination stack 102.

In addition to extracting and inserting a plurality of stacked storage containers 101, the load handling device 120 of Figure 7 can be used to change the order of the storage containers 101 in a stack 102. In particular, the load handling device 104 can be used to extract a portion 102a of the stack 102 (i.e. one or more storage containers in the stack) from a first position in the stack 102 (i.e. either the top, middle or bottom of the stack), and to reinsert the extracted portion 102a of the stack 102 in a different, second position.

By way of example, the load handling device 120 can implement an extraction operation to extract a portion 102a of a stack 102 that comprises a plurality of stacked storage containers 101, as described above in relation to Figures 9a to 9c. However, rather than moving away from the source stack 102 with the extracted portion 102a of the stack 102, the load handling device 120 then reinserts the extracted storage containers, as illustrated in Figures 10a and 10b. To do so, the load handling device uses the first container lifting mechanism of the container displacement device 123 to raise the first container support assembly 125 such that the extracted portion 102a of the stack 102 is above the remaining portion of the stack 102 that is resting on the floor. In the example of Figures 10a and 10b, the remaining portion of the stack 102 comprises those storage containers 101 that were below the extracted portion 102a in the initial stack 102 and those storage containers 101 that were above the extracted portion 102a in the initial stack 102.

The load handling device 120 then uses the transfer mechanism of the container displacement device 123 to move the extracted portion 102a from the rearward position to the forward position, through the opening 127 in the body 121. At this stage, the extracted portion 102a is supported on the first container support members 125a, 125b and is horizontally aligned relative to the remaining portion of the stack 102 that is resting on the surface beneath the stack 102, as shown in Figure 10a. The load handling device 120 then uses the first container lifting mechanism of the container displacement device 123 to lower the extracted portion 102a until the bottom storage container 101a of the extracted portion 102a is resting upon the top storage container 101 of the remaining portion of the stack 102 and the first container support members 115a, 115b have disengaged and are lower than the cooperating features of the bottom storage container 101a of the extracted portion 102a, as shown in Figure 10b. At this stage, the final stack 102 comprises the same storage containers as the initial stack but in a different order.

Figures 11a to 11g then illustrates a sequence showing the load handling device 120 of Figure 7 implementing an operation in which a stack of storage containers 101 is delivered to and unstacked at a drop-off point. In this example, the drop-off point comprises a conveyor 130 that is arranged to receive storage containers 101 and convey the received storage containers 101. In particular, the conveyor 130 comprises a receiving section 131 that is arranged to receive storage containers 101 delivered to the drop-off point by a load handling device 120, and a further section 132 that is arranged to receive storage containers 101 from the receiving section 131 and to convey the storage containers 101 away from the receiving section 131. To do so, the receiving section 131 and the further section 132 of the conveyor 130 are arranged to be independently operable.

In order to implement this operation, the load handling device 120 collects the stack 102 and travels to the drop-off point with the stack supported on the second container support assembly 126 of the second container lifting device 124. Prior to arriving at the drop-off point, the load handling device 120 uses second container lifting mechanism to ensure that the first storage container 101d of the stack 102 (i.e. the bottom storage container) is raised to a height sufficient to allow the load handling device 120 to position the stack 102 directly above the receiving section 131 of the conveyor 150.

Upon arriving at the drop-off point, the load handling device 120 uses the first lifting mechanism of the container displacement device 123 to ensure that the first support members 125a, 125b of the first container support assembly 125 have engaged the cooperating features of the second storage container 101e (i.e. the second from bottom storage container, which is immediately above the first storage container 101d) of the stack 102, such that the second storage container 101e is supported on the first container support assembly 125. The load handling device 120 then uses the second lifting mechanism to lower the second container support assembly 126 and the first storage container 101d supported thereon away from the second storage container 101e, and until the storage container 101d contacts the receiving section 131 of the conveyor 130. The load handling device 120 continues to lower the second container support assembly 126 until the second support members 126a, 126b have disengaged the cooperating features of the first storage container 101d, as shown in Figure 11a. The receiving section 131 of the conveyor 130 then conveys the first storage container 101d away on to the further section 132 of the conveyor 130 such that the receiving section 131 is unoccupied, as shown in Figure 11b.

The load handling device 120 then uses the first container lifting mechanism of the container displacement device 123 to lower the first container support assembly 125 and the second storage container 101e supported thereon until the second storage container 101e contacts the receiving section 131 of the conveyor 150. The load handling device 120 continues to lower the first container support assembly 125 until the first support members 125a, 125b have disengaged the cooperating features of the second storage container 101e, as shown in Figure 11c.

The load handling device 120 then uses the transfer mechanism of the container displacement device 123 to move the first container support assembly 125 from the forward position to the rearward position, as shown in Figure 11d. The load handling device 120 then uses the first lifting mechanism to raise the first container support assembly 125 above the second storage container 101e that is resting on the receiving section 131 of the conveyor 130 and below the cooperating features of the third storage container 101f (i.e. the third from bottom storage container, which is immediately above the second storage container 101e). The load handling device 120 then uses the transfer mechanism to move the first container support assembly 125 from the rearward position to the forward position such that the first support members 125a, 125b are directly below the cooperating features of the third storage container 101f.

The load handling device 120 then uses the first lifting mechanism to raise the first container support assembly 125 such that first support members 125a, 125b engage the cooperating features of the third storage container 1011 and lift the third storage container 101f upwards away from the second storage container 101e that is resting on the receiving section 131 of the conveyor 130, as shown in Figure lie. At this stage, the second storage container 101c1 is resting on the receiving section 131 of the conveyor 130 and is separated from the storage containers 101 that remain stacked on the load handling device 120 (i.e. the third storage container 101f and any storage containers supported thereon). The receiving section 131 of the conveyor 130 then conveys the second storage container 101c1 away on to the further section 132 of the conveyor 130 such that the receiving section 131 is unoccupied, as shown in Figure llf. Prior to, or concurrently with, the conveying of the second storage container 101e away from the receiving section 131, the further section 132 may convey the first storage container 101d onwards so as to make space for the second storage container 101e.

The load handling device 120 then uses the first lifting mechanism to lower the first container support assembly 125 and the third storage container 101f supported thereon until the third storage container 101f contacts the receiving section 131 of the conveyor 130, as shown in Figure 11g. The operation can continue until all of the storage containers 101 that made up the initial stack 102 have been unstacked onto the conveyor.

Figures 12, 13 and 14 are schematic illustrations of yet further examples of load handling devices 140, 150, 160 suitable for lifting and moving storage containers 101 stacked in a storage system 100 such as those shown in Figures 1 and 6. Each of the load handling devices 140, 150, 160 illustrated in Figures 12, 13 and 14 are essentially the same as the load handling device 120 described above with reference to Figure 7. However, in each of Figures 12, 13 and 14 the load handling devices 140, 150, 160 further comprises a robotic arm 142, 152, 162 that is arranged to pick items from a storage container 101 supported by the load handling device 140, 150, 160. Each of the load handling devices 140, 150, 160 then also comprises one or more receptacle supports 145, 155, 165 that are each arranged to support a receptacle 160 for receiving items deposited therein by the robotic arm 142, 152, 162.

In the example of Figure 12, the robotic arm 142 is movably mounted to the body 141 of the load handling device 140 such that it moves vertically with the container displacement device 143. In particular, the robotic arm 142 is mounted to a platform 146 that is arranged to be moved vertically by the first lifting mechanism. The load handling device 140 is then provided with multiple receptacle supports 145 that are vertically distributed along at least one of the outer side surfaces of the body 141 of the load handling device 140. In this example, each receptacle support 145 comprises a box within which a receptacle 170 in the form of a bag can be supported. The robotic arm 142 can then pick from a storage container 101 supported on the first container support assembly of the container displacement device 143 and deposit items picked from the storage container 101 into receptacles supported by any of the vertically distributed receptacle supports 145.

In the example of Figure 12, the platform 146 and the robotic arm 142 are mounted to the rear (R) of the body 141 of the load handling device 140 such that the robotic arm 142 is arranged to pick from a storage container 101 supported on the first container support assembly when in the rearward position. Such an arrangement provides that the operation of the container displacement device 143 and the container lifting device 144 can be coordinated to extract a target storage container 101 from a stack 102 so as to allow the robotic arm 142 to pick one or more items from the target storage container 101, and then return the target storage container 101 directly back into the stack 102.

In the example of Figure 13, the robotic arm 152 is fixedly mounted to the body 151 of the load handling device 150. In particular, the robotic arm 152 is mounted to an upper surface of the body 151 of the load handling device 150. The load handling device 150 is then provided with a receptacle support 155 on each of the outer side surfaces of the body 151 of the load handling device 150 adjacent to the upper surface of the body 151. In this example, each receptacle support 155 comprises a hook to which a receptacle 170 in the form of a bag can be attached. The robotic arm 152 can then pick from a storage container 101 that is supported on the first container support assembly and that has been lifted to be within range of the robotic arm 152, and deposit items picked from the storage container 101 into receptacles 170 supported by either of the receptacle supports 155.

In the example of Figure 14, the robotic arm 162 is fixedly mounted to the body 161 of the load handling device 160. In particular, the robotic arm 162 is mounted to a platform 166 that is attached to an outer side surface of the body 161 of the load handling device 160. The load handling device 160 is then provided with a receptacle support 165 that is mounted to the body 161 of the load handling device 160, directly below the robotic arm 162. In this example, the receptacle support 165 comprises a shelf on which a receptacle 170 in the form of a storage container can be supported. The robotic arm 162 can then pick from a storage container 101 that is supported on the first container support assembly and that has been lifted to be within range of the robotic arm 162, and deposit items picked from the storage container 101 into a receptacle 170 supported by on the receptacle support 165.

In the example of Figure 14, the robotic arm 162 and receptacle support 165 are arranged such that they face to the rear (R) of the body 161 of the load handling device 160 such that the robotic arm 162 is arranged to pick from a storage container 101 supported on the first container support assembly when in the rearward position. Such an arrangement provides that the operation of the container displacement device 163 and the container lifting device 164 can be coordinated to extract a target storage container 101 from a stack 102 so as to allow the robotic arm 162 to pick one or more items from the target storage container 101, and then return the target storage container 101 directly back into the stack 102.

Figure 15 then illustrates a specific example of load handling device 180 that is suitable for lifting and moving storage containers 101 stacked in a storage system 100 such as those shown in Figures 1 and 6. The general arrangement and functionality of the load handling device 180 of Figure 15 is essentially the same as that of the load handling device 120 of Figure 7, and corresponding reference numerals have therefore been used for like or corresponding parts or features.

In the example of Figure 15, the body 181 comprises a framework to which the remaining components of the load handling device 180 are mounted. The framework that defines the body 181 of the load handling device 180 further comprises an opening 187 arranged to allow one or more storage containers 101 supported on the first container support assembly 185 to at least partially pass through the body 181 when moving between the forward position, in which the first container support assembly 185 extends forward from the body 181, and the rearward position, in which the first container support assembly 185 extends at least partially rearward (R) from the body 181.

The load handling device 180 then further comprises two separate arms 188a, 188b that extend forward from opposite sides at the front of the body 181. The movement means 182a, 182b then comprises a pair of forward wheels 182a, with each forward wheel 182a being mounted at the distal end of each of the arms 188a, 188b, and a pair of rear wheels 182b that are directly mounted, on opposite sides, to the rear (R) of the body 181 of the load handling device 180. In this example, the forward wheels 182a are caster wheels or any other form of multidirectional wheel, whilst the rear wheels 182b are differentially driven wheels.

The first container support assembly 185 of the container displacement device 183 comprises a pair of first support members or forks 185a, 185b that extend forward (F) from the body 181 of the load handling device 180, when in the forward position, such that they can each be located underneath a cooperating feature of a storage container 101. The first container support assembly 185 is movably mounted to a first vertical track 192, provided on a rear section of the body 181, and is attached to a first lifting mechanism 189 that is arranged to move the first container support assembly 185 along the first vertical track 192. In the example of Figure 15, the first lifting mechanism 189 of the container displacement device 183 comprises a motorised chain drive that extends between the top and bottom of the body 201. The transfer mechanism 190 of the container displacement device 183 then comprises a motorised rack and pinion mechanism that connects the first container support assembly 185 to the first lifting mechanism 189. In the example of Figure 15, the rack is provided on the first container support assembly 185, whilst a motor driven pinion is provided on carriage that is attached to the chain of the chain drive that provides the first lifting mechanism 189.

The second container support assembly 186 of the container lifting device 184 also comprises a pair of second support members or forks 186a, 186b that extend forward (F) from the body 181 of the load handling device 180 such that they can each be located underneath a cooperating feature of a storage container 101. The second container support assembly 186 is movably mounted to a second vertical track 193, provided on a forward section of the body 181, and is attached to a second lifting mechanism 191 that is arranged to move the second container support assembly 186 along the second vertical track 193. In the example of Figure 15, the second lifting mechanism 191 of the container lifting device 184 comprises a motorised chain drive that extends between the top and bottom of the body 181.

The load handling device 180 then further comprises a housing 194 that is mounted to the body 181 and that supports various other components of the load handling device 18-. In the example of Figure 15, these components include motors that drive the differentially drive rear wheels 182b, batteries that provide electrical energy to power the load handling device 180, and electronics that are involved in the control of the load handling device 180 and communication between the load handling device 180 and any central controller of the storage system 100. In the example of Figure 15, the housing 194 is mounted to the bottom of the body 181 of the load handling device 180 in order to ensure that the centre of gravity of the load handling device 180 is a low as possible. Furthermore, the housing 194 is mounted at the rear (R) of body 181 in order to at least partially counterbalance the weight of any storage containers 101 supported at the front (F) of the load handling device 180.

Figures 16 and 17 illustrate a further example of a storage system 200 comprising a plurality of freestanding stacks 202 of storage containers 201 stored in a workspace. As in the example of Figure 1, the stackable storage containers 201 are stacked on top of one another to form the stacks 202 that are freestanding on a floor or surface 203 of the workspace. In contrast with the example of Figure 1, the storage system 200 of Figures 16 and 17 then further comprises a grid 206 disposed on the surface 203 on which stacks 202 are resting.

As shown in Figures 16 and 17, the grid 206 defines grid spaces 207 and each stack 202 of containers 201 is disposed within a grid space 207. The grid 206 comprises a first set of parallel horizontal rails or tracks 206a arranged perpendicularly to a second set of parallel horizontal rails or tracks 206b to form a grid pattern. The storage system 200 then further comprises load handling devices 210 for lifting and moving the storage containers 201 in order to deposit storage containers in and retrieve storage containers from the stacks 202. In particular, the load handling devices 210 are arranged to be able to laterally insert storage containers 201 into a stack 202 and laterally extract storage containers 201 from a stack 202. The load handling devices 210 are therefore arranged to move over the surface beneath the stacks 202 from where the load handling devices 210 can access the side of any exposed stack 202.

In the system illustrated in Figures 16 and 17, the grid 206 is arranged to support and guide the movement of the load handling devices 210 over the surface 203. In particular, the first set of horizontal tracks 206a guide movement of the load handling devices 210 in a first direction (X) over the surface 203, and the second set of horizontal tracks 206b, arranged perpendicular to the first set 206a, guide movement of the load handling devices 210 in a perpendicular, second direction (Y) over the surface 203. In this way, the horizontal tracks 206 allow movement of the load handling devices 210 in two dimensions in the horizontal plane so that a load handling device 210 can be moved into position adjacent to an exposed side of any of the stacks 202.

As shown in Figures 16 and 17, each load handling device 210 is arranged to travel in the X and directions on the tracks of the grid 106. To do so, the load handling device 210 comprises a body 211 mounted on movement means 212a, 212b that are arranged to allow the load handling device 110 to move across the grid 206. The movement means comprises a first set of wheels 212a arranged to engage with two adjacent tracks of the first set of tracks 206a and a second set of wheels 212b arranged to engage with two adjacent tracks of the second set of tracks 206b. Each set of wheels 212a, 212b can be lifted and lowered, so that either the first set of wheels 212a or the second set of wheels 212b is engaged with the respective set of tracks 206a, 206b at any one time. In the example shown in Figures 16 and 17, the first set of wheels 212a comprises a pair of wheels on the front of the body 211 and a pair of wheels on the back of the body 211, whilst the second set of wheels 212b comprises a pair of wheels on each side of the body 211.

When the first set of wheels 212a is engaged with the first set of tracks 206a and the second set of wheels 212b are lifted clear from the second set of tracks 206b, the wheels 212a can be driven, by way of a drive mechanism (not shown) housed in the body 211, to move the load handling device 210 in the X direction. To move the load handling device 210 in the Y direction, the first set of wheels 212a are lifted clear of the first set of tracks 206a, and the second set of wheels 212b are lowered into engagement with the second set of tracks 206b.

The load handling device 210 then further comprises a container displacement device 213 mounted to the body 211 and a separate, container lifting device 214 that is also mounted to the body 211. The container displacement device 213 is arranged to move any storage containers 201 supported on container displacement device 213 vertically and horizontally relative to the body 211, whilst the container lifting device 214 is arranged to move any storage containers 201 supported thereon vertically relative to the body 211. Coordinating the operation of the container displacement device 213 and the container lifting device 214 therefore enables the load handling device 210 to laterally insert storage containers 211 into and extract storage containers 201 from a stack 202.

The container displacement device 213 comprises a first container support assembly 215 arranged to support a storage container 201, a first lifting mechanism (not shown) arranged to move the first container support assembly 215 vertically relative to the body 211 of the load handling device 210, and a transfer mechanism 218 arranged to move a storage container supported on the first container support assembly 215 horizontally relative to the body 211 of the load handling device 210. The first container lifting mechanism moves the first container support assembly 215, and any storage container 201 supported thereon, vertically between a first upper position and a first lower position.

The second container lifting device 214 then comprises a second container support assembly 216 and a second lifting mechanism (not shown) that is arranged to move the second container support assembly 216 vertically relative to the body 211 of the load handling device 210. The second lifting mechanism moves the second container support assembly 216, and any storage container 201 supported thereon, vertically between a second upper position and a second lower position.

In contrast with the load handling device 110 of Figure 2, rather than moving the first container support assembly 215, the transfer mechanism 218 is arranged to move a storage container 201 supported on the first container support assembly 215 horizontally between a first, forward position and a second, rearward position. For example, the transfer mechanism 218 may comprise a conveyor, such as belt, chain or roller conveyor, which is mounted on the first container support assembly 215 and that is arranged to convey a storage container 201 supported on the first container support assembly 215 between the forward position, in which the supported storage container 210 is located towards a forward end of the first container support assembly 215 (i.e. in front of the body 211 of the load handling device 210), and the rearward position, in which the supported storage container 210 is located towards a rearward end of the first container support assembly 215.

The body 211 of the load handling device 210 then further comprises an opening 217 arranged to allow a storage container 201 supported on the first container support assembly 215 to move into a cavity or recess within the body 211 of the load handling device 210. The first container support assembly 215 then extends through the opening 217 into the cavity or recess such that a supported storage container located towards the rearward end of the first container support assembly 215 is at least partially disposed within the cavity of the body 211.

The load handling device 210 can then implement an extraction operation, in which an outgoing storage container 201 is extracted laterally from a source stack 202, and an insertion operation, in which an ingoing storage container 201 is inserted laterally into a destination stack 202, by performing essentially the same steps as described above with reference to Figures 3a to 3g. However, as the first container support assembly 215 does not itself move between a forward position and a rearward position, the first container support assembly 215 remains beneath the second container support assembly 216. Consequently, when moving the second container support assembly 216 down low enough to deposit a storage container to the floor or to lift a storage container from the floor, the first container support assembly 215 is moved so as to be lower than the second container support assembly 216.

It will be appreciated that the features described hereinabove may all 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 arrangement. Many variations and modifications not explicitly described above are possible without departing from the scope of the invention as defined in the appended claims.

It will be understood that the above description of is given by way of example only and that various modifications may be made by those skilled in the art. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the scope of this invention.

Claims

CLAIMS1. A load handling device for lifting and moving storage containers arranged in stacks in a storage system, the load handling device comprising: a body mounted on movement means; a container displacement device mounted to the body, wherein the container displacement device is arranged to move one or more stacked storage containers supported thereon vertically and horizontally relative to the body; and a container lifting device mounted to the body, wherein the container lifting device is arranged to move a storage container supported thereon vertically relative to the body.
2. A load handling device according to claim 1, wherein the container displacement device is arranged to move one or more stacked storage containers supported thereon horizontally relative to the body between a forward position and a rearward position.
3. A load handling device according to any of claims 1 and 2, wherein the load handling device is arranged such that, when one or more stacked storage containers supported on the container displacement device are in the forward position, the one or more stacked storage containers supported on the first container lifting device are located in front of the body.
4. A load handling device according to any of claims 1 to 3, wherein the load handling device is arranged such that, when one or more stacked storage containers supported on the container displacement device are in the forward position, the one or more stacked storage containers supported on the container displacement device are horizontally aligned with one or more stacked storage containers supported on the container lifting device.
5. A load handling device according to any of claims 1 to 4, wherein the load handling device is arranged such that, when one or more stacked storage containers supported on the container displacement device are in the rearward position, the one or more stacked storage containers supported on the first container lifting device are horizontally offset relative to one or more stacked storage containers supported on the container lifting device.
6. A load handling device according to any of claims 1 to 5, wherein the stacks of storage containers are supported on a surface, and the movement means are arranged to allow the load handling device to move across the surface.
7. A load handling device according to any of claims 1 to 6, wherein the load handling device is arranged such that the container lifting device can move one or more stacked storage containers supported on the container lifting device vertically past one or more stacked storage containers supported on the container displacement device.
8. A load handling device according to any of claims 1 to 7, wherein the container displacement device comprises a first container support assembly arranged to support one or more stacked storage containers, a first lifting mechanism arranged to move the first container support assembly vertically relative to the body, and a transfer mechanism arranged to move the one or more stacked storage containers supported on the first container support assembly horizontally relative to the body between a forward position and a rearward position
9. A load handling device according to claim 8, wherein the container lifting device comprises a second container support assembly arranged to support one or more stacked storage containers, and a second lifting mechanism arranged to move the second container support assembly vertically relative to the body
10. A load handling device according to any of claims 8 and 9, wherein the first container support assembly is arranged to extend forward from the body of the load handling device such that the first container support assembly can be located under at least a portion of a storage container that is immediately forward of the body and engage the storage container when raised by the first lifting mechanism.
11. A load handling device according to any of claims 8 to 10, wherein the second container support assembly is arranged to extend forward from the body of the load handling device such that the second container support assembly can be located under at least a portion of a storage container that is immediately forward of the body and engage the storage container when raised by the second lifting mechanism.
12. A load handling device according to any of claims 8 to 11, wherein the body comprises an opening arranged to allow one or more stacked storage containers supported on the first container support assembly to move at least partially into the body of the load handling device when moving between the forward position and the rearward position
13. A load handling device according to any of claims 8 to 12, wherein the transfer mechanism is arranged to move the first container support assembly horizontally relative to the body between a forward position and a rearward position.
14. A load handling device according to claim 13, wherein the load handling device is arranged such that, when the first container support assembly is in the rearward position, the first container support assembly does not horizontally overlap with the second container support assembly.
15. A load handling device according to any of claims 13 and 14, wherein the load handling device is arranged such that, when the first container support assembly is in the forward position, the first container support assembly is horizontally aligned with the second container support assembly.
16. A load handling device according to any of claims 8 to 12, wherein the transfer mechanism comprises a conveyor mounted on the first container support assembly and that is arranged to convey one or more stacked storage containers supported on the first container support assembly between the forward position and the rearward position.
17. A load handling device according to claim 16, wherein, when in the forward position, the one or more stacked storage containers are located towards a forward end of the first container support assembly and, when in the rearward position, in the one or more stacked storage containers are located towards a rearward end of the first container support assembly.
18. A load handling device according to any of claims 1 to 17, wherein the load handling device further comprises a robotic arm arranged to pick items from a container supported by the load handling device.
19. A load handling device according to claim 18, and further comprising a receptacle support arranged to support a receptacle for receiving and holding items, wherein the robotic arm is arranged to deposit items picked from a storage container supported by the load handling device into a receptacle located on the receptacle support.
20. A storage and retrieval system comprising: a plurality of freestanding stacks of storage containers stored in a workspace; and at least one load handling device according to any of claims 1 to 19.
21. A storage and retrieval system according to claim 20, and further comprising a central control facility for controlling and coordinating the movement and operation of the load handling devices.
22. A storage and retrieval system according to any of claims 20 or 21, wherein the stacks of storage containers are arranged in rows that are grouped together to form separate blocks of stacks, with each block of stacks being at least partially bounded by intersecting aisles.
23. A method of operating a load handling device to insert one or more ingoing storage containers into a destination stack of storage containers, the method comprising: using a container displacement device of the load handling device to lift the one or more ingoing storage containers and to support the one or more ingoing storage containers in a rearward position; using a movement means of the load handling device to position the load handling device with the destination stack immediately in front of the load handling device; using a container lifting device of the load handling to lift at least a portion of the storage containers of the destination stack; using the container displacement device to move the one or more ingoing storage containers horizontally from the rearward position to a forward position in which the one or more ingoing storage containers are aligned beneath the lifted portion of the destination stack and to lower the one or more ingoing storage containers; and using the container lifting device to lower the lifted portion of the destination stack on to the one or more ingoing storage containers.
24. A method according to claim 23, and further comprising: prior to positioning the load handling device with the destination stack immediately in front of the load handling device, using the container displacement device to move the one or more ingoing storage containers horizontally from the forward position to the rearward position
25. A method of operating a load handling device to extract one or more outgoing storage containers from a source stack of storage containers, the method comprising: using a movement means of the load handling device to position the load handling device with the source stack immediately in front of the load handling device; using a container lifting device of the load handling to lift at least a portion of the storage containers of the source stack; using a container displacement device of the load handling device to lift the one or more outgoing storage containers and to move the one or more outgoing storage containers from a forward position to a rearward position in which the one or more ingoing storage containers do not horizontally overlap with the lifted portion of the source stack; and using the container lifting device to lower the lifted portion of the source stack on to the one or more ingoing storage containers.