Patent Description:
<FIG> discloses a framework structure <NUM> of a typical prior art automated storage and retrieval system and <FIG> disclose different container handling vehicles <NUM> of such a system.

The framework structure <NUM> comprises a plurality of upright members <NUM> and a plurality of horizontal members <NUM>, which are supported by the upright members <NUM>. The members <NUM>, <NUM> may typically be made of metal, e.g. extruded aluminium profiles.

The framework structure <NUM> defines a storage grid <NUM> comprising storage columns <NUM> arranged in rows, in which storage columns <NUM> store storage containers <NUM>, also known as bins, are stacked one on top of another to form stacks <NUM>. Each storage container <NUM> may typically hold a plurality of product items (not shown), and the product items within a storage container <NUM> may be identical, or may be of different product types depending on the application. The framework structure <NUM> guards against horizontal movement of the stacks <NUM> of storage containers <NUM>, and guides vertical movement of the containers <NUM>, but does normally not otherwise support the storage containers <NUM> when stacked.

A rail system <NUM> is arranged in a grid pattern across the top of the storage columns <NUM>, on which rail system <NUM> a plurality of container handling vehicles <NUM> are operated to raise storage containers <NUM> from and lower storage containers <NUM> into the storage columns <NUM>, and also to transport the storage containers <NUM> above the storage columns <NUM>. The rail system <NUM> comprises a first set of parallel rails <NUM> arranged to guide movement of the container handling vehicles <NUM> in a first direction X across the top of the frame structure <NUM>, and a second set of parallel rails <NUM> arranged perpendicular to the first set of rails <NUM> to guide movement of the container handling vehicles <NUM> in a second direction Y, which is perpendicular to the first direction X. In this way, the rail system <NUM> defines grid columns <NUM> above which the container handling vehicles <NUM> can move laterally above the storage columns <NUM>, i.e. in a plane which is parallel to the horizontal X-Y plane.

Each container handling vehicle <NUM> comprises a vehicle body <NUM> and first and second sets of wheels <NUM>, <NUM> which enable the lateral movement of the container handling vehicle <NUM>, i.e. the movement in the X and Y directions. In <FIG> two wheels in each of the sets <NUM>, <NUM> are visible, while in <FIG> only two wheels in one of the set of wheels <NUM> are visible. The first set of wheels <NUM> is arranged to engage with two adjacent rails of the first set <NUM> of rails, and the second set of wheels <NUM> arranged to engage with two adjacent rails of the second set <NUM> of rails. Each set of wheels <NUM>, <NUM> can be lifted and lowered, so that the first set of wheels <NUM> and/or the second set of wheels <NUM> can be engaged with the respective set of rails <NUM>, <NUM> at any one time.

Each container handling vehicle <NUM> also comprises a lifting device <NUM> (see <FIG>) for vertical transportation of storage containers <NUM>, e.g. raising a storage container <NUM> from and lowering a storage container <NUM> into a storage column <NUM>. The lifting device may be arranged inside the body <NUM> (as in <FIG>) or outside the body <NUM> (as disclosed in <FIG>). The lifting device <NUM> may comprise a lifting frame <NUM> which is adapted to engage a storage container <NUM>, which lifting frame <NUM> can be lowered from the vehicle body <NUM> so that the position of the lifting frame with respect to the vehicle body <NUM> can be adjusted in a third direction Z, which is orthogonal the first direction X and the second direction Y.

Conventionally, and also for the purpose of this application, Z=<NUM> identifies the uppermost layer of the grid <NUM>, i.e. the layer immediately below the rail system <NUM>, Z=<NUM> the second layer below the rail system <NUM>, Z=<NUM> the third layer etc. In the embodiment disclosed in <FIG>, Z=<NUM> identifies the lowermost, bottom layer of the grid <NUM>. Consequently, as an example and using the Cartesian coordinate system X, Y, Z indicated in <FIG>, the storage container identified as <NUM>' in <FIG> can be said to occupy grid location or cell X=<NUM>, Y=<NUM>, Z=<NUM>. The container handling vehicles <NUM> can be said to travel in layer Z=<NUM> and each grid column can be identified by its X and Y coordinates.

Each container handling vehicle <NUM> comprises a storage compartment or space for receiving and stowing a storage container <NUM> when transporting the storage container <NUM> across the grid <NUM>. The storage space may comprise a cavity arranged centrally within the vehicle body <NUM> (<FIG>), e.g. as is described in <CIT>. Alternatively, the storage compartment or space can be arranged on the side of the body as disclosed in <FIG>, i.e. the container handling vehicles may have a cantilever construction, as is described in <CIT>.

The container handling vehicles <NUM> may have a footprint <NUM> (see <FIG>), i.e. an extension in the X and Y directions, which is generally equal to the lateral or horizontal extension of a grid column <NUM>, i.e. the extension of a grid column <NUM> in the X and Y directions, e.g. as is described in <CIT>.

Alternatively, the container handling vehicles <NUM> may have a footprint which is larger than the lateral extension of a grid column <NUM>, e.g. as is disclosed in <CIT>.

The rail system <NUM> may be a single rail system, as is shown in <FIG>. Alternatively, the rail system <NUM> may be a double rail system, as is shown in <FIG>, thus allowing a container handling vehicle <NUM> having a footprint <NUM> generally corresponding to the lateral extension of a grid column <NUM> to travel along a row of grid columns even if another container handling vehicle <NUM> is positioned above a grid column neighbouring that row.

In a storage grid, a majority of the grid columns <NUM> are storage columns <NUM>, i.e. grid columns where storage containers are stored in stacks. However, a grid normally has at least one grid column which is used not for storing storage containers, but which comprises a location where the container handling vehicles can drop off and/or pick up storage containers so that they can be transported to an access station where the storage containers can be accessed from outside of the grid or transferred out of or into the grid. Within the art, such a location is normally referred to as a "port" and the grid column in which the port is located may be referred to as a port column.

The grid <NUM> in <FIG> comprises two port columns <NUM> and <NUM>. The first port column <NUM> may for example be a dedicated drop-off port column where the container handling vehicles <NUM> can drop off storage containers to be transported to an access or a transfer station (not shown), and the second port <NUM> column may be a dedicated pick-up port column where the container handling vehicles <NUM> can pick up storage containers that have been transported to the grid <NUM> from an access or a transfer station.

The access station may typically be a picking or a stocking station where product items are removed from or positioned into the storage containers. In a picking or a stocking station, the storage containers are normally never removed from the automated storage and retrieval system, but are returned back into the grid once accessed. A port can also be used for transferring storage containers out of or into the grid, e.g. for transferring storage containers to another storage facility (e.g. to another grid or to another automated storage and retrieval system), to a transport vehicle (e.g. a train or a lorry), or to a production facility.

A conveyor system comprising conveyors is normally employed to transport the storage containers between the ports and the access station.

If the port and the access station are located at different levels, the conveyor system may comprise a lift device for transporting the storage containers vertically between the port and the access station.

The conveyor system may be arranged to transfer storage containers between different grids, e.g. as is described in <CIT>.

<CIT> discloses an example of a prior art access system having conveyor belts (<FIG> in <CIT>) and a frame mounted track (<FIG> in <CIT>) for transporting storage containers between ports and work stations where operators can access the storage containers.

When a storage container <NUM> stored in the grid <NUM> disclosed in <FIG> is to be accessed, one of the container handling vehicles <NUM> is instructed to retrieve the target storage container from its position in the grid <NUM> and transport it to the drop-off port <NUM>. This operation involves moving the container handling vehicle <NUM> to a grid location above the storage column in which the target storage container is positioned, retrieving the storage container from the storage column using the container handling vehicle's lifting device (not shown), and transporting the storage container to the drop-off port <NUM>. If the target storage container <NUM> is located deep within a stack <NUM>, i.e. with one or a plurality of other storage containers positioned above the target storage container, the operation also involves temporarily moving the above-positioned storage containers prior to lifting the target storage container from the storage column. This step, which is sometimes referred to as "digging" within the art, may be performed with the same container handling vehicle <NUM> that is subsequently used for transporting the target storage container to the drop-off port <NUM>, or with one or a plurality of other cooperating container handling vehicles <NUM>. Alternatively, or in addition, the automated storage and retrieval system may have container handling vehicles <NUM> specifically dedicated to the task of temporarily removing storage containers <NUM> from a storage column. Once the target storage container has been removed from the storage column, the temporarily removed storage containers <NUM> can be repositioned into the original storage column. However, the removed storage containers <NUM> may alternatively be relocated to other storage columns.

When a storage container <NUM> is to be stored in the grid <NUM>, one of the container handling vehicles <NUM> is instructed to pick up the storage container from the pick-up port <NUM> and transport it to a grid location above the storage column where it is to be stored. After any storage containers <NUM> positioned at or above the target position within the storage column stack have been removed, the container handling vehicle <NUM> positions the storage container <NUM> at the desired position. The removed storage containers may then be lowered back into the storage column, or relocated to other storage columns.

For monitoring and controlling the automated storage and retrieval system, e.g. monitoring and controlling the location of respective storage containers within the grid <NUM>, the content of each storage container <NUM>, and the movement of the container handling vehicles <NUM> so that a desired storage container can be delivered to the desired location at the desired time without the container handling vehicles <NUM> colliding with each other, the automated storage and retrieval system comprises a control system, which typically is computerised and comprises a database for keeping track of the storage containers.

<CIT>, which has been identified as an intermediate document according to Article <NUM>(<NUM>) EPC during the examination procedure before the EPO, discloses an automated storage and retrieval system comprising a three-dimensional grid comprising a plurality of storage columns in which storage containers are stored one on top of another in vertical stacks, and at least one port through which the storage containers can be transferred out of and/or into the grid; and a plurality of container handling vehicles which are operated laterally on the grid for retrieving storage containers from and storing storage containers in the storage columns, and for transporting the storage containers laterally across the grid. The grid comprises a plurality of transfer columns for temporarily storing storage containers when in transit between the storage columns and the at least one port, wherein the container handling vehicles are arranged to transport the storage containers between the storage columns and the transfer columns, and wherein a port access vehicle is arranged to transport the storage containers between the transfer columns and the at least one port in a plane located above the container handling vehicles.

<CIT>, which has been identified as the 'closest prior art' during the examination procedure before the EPO, discloses a system for picking items from a containerised storage system. The items are stored in storage bins in stacks within a framework comprising a grid system disposed above the stacks of bins. Robotic devices are disposed on the grid, the devices acting so as to pick containers from the stacks of bins. The storage system is provided with at least one picking device for picking items from bins and depositing them directly in delivery containers.

A problem associated with known automated storage and retrieval systems is that the area surrounding the ports may become congested with container handling vehicles instructed to drop off or pick up storage containers. This may seriously impede the operation of the automated storage and retrieval system. In small systems this situation may possibly be alleviated by adding ports to the grid, as this will allow the container handling vehicles to be distributed among a larger number of ports in order to avoid congestion. However, if ports are added, the conveyor system infrastructure must normally be increased. This requires space, which may not necessarily be available. Also, adding conveyor system infrastructure is costly.

Furthermore, the current trend within the automated storage and retrieval system industry is that there is an increasing demand for larger storage grids. Since the number of storage containers stored in a grid generally scales as the volume of the grid, but the space available for ports generally scales as the surface of the grid, increasing the number of ports will not satisfactory solve the congestion problem when the grid size increases.

In view of the above, it is desirable to provide an automated storage and retrieval system, and a method for operating such a system, that solve or at least mitigate the aforementioned problem related to congestion of container handling vehicles at the ports. Another objective of the invention is to increase the capacity in terms of moving more storage containers in less time than in the prior art solutions.

The invention is set forth in the independent claims and the dependent claims describe alternatives of the invention.

The invention relates to an automated storage and retrieval system according to claim <NUM> comprising:.

wherein the system further comprises:
a multi trolley vehicle for transporting storage containers between the storage columns and at least one deployment area, which deployment area provides direct access to an area outside the grid pattern, the multi trolley vehicle comprising:.

Thus, according to the invention, a drive vehicle connected to a trolley assembly, the setup which is also referred to as multi trolley vehicle, is capable of transporting one or a group of storage containers between the storage columns and the at least one deployment area, which deployment area provides direct access to an area outside the grid pattern. Furthermore, the rail system is preferably only the top layer of the automated storage and retrieval system, the storage columns are defined volumes below the rail system.

The system is provided with at least one drive vehicle, i.e. the first drive vehicle, on one end of the trolley assembly or partway or midway within the trolley assembly, thereby defining a multi trolley vehicle. The at least one drive vehicle can thus be seen as locomotive, towing vehicle, hauling vehicle, traction engine, tractive machine, tractive unit, tractor, i.e. any vehicle capable of being connected to the trolley assembly. Various terms are used in the following description of the system defined by at least one drive vehicle connected to a trolley assembly, including multi trolley vehicle. If the system comprises more than one drive vehicle, e.g. also a second drive vehicle, the combination of drive vehicles and trolley assembly is still referred to as a multi trolley vehicle. The drive vehicle(s) may either push or pull the trolley assembly, and can be arranged in front of, and or behind, and or partway within, said trolley assembly. Alternatively, the drive vehicle(s) may also pull or drag the trolley assembly sideways. In this latter aspect, the drive vehicles and the trolleys are preferably configured with moving devices directed in both the X direction and Y direction. The deployment area can in one aspect be a port, in another aspect be a factory area, in yet another aspect be a production facility, in yet another aspect another rail or grid system with or without a dedicated storage system. In one aspect, if the deployment area is a port or port area which has access from outside the grid pattern (rail system), the port or port area can be arranged within or outside of the grid pattern, either extending along an end row or extending into or out from the the grid pattern. Furthermore, the at least one drive vehicle and trolley assembly can move on the rail system or in a plane horizontally above or below the rail system (for example on a double rail). If driving in a plane horizontally below the rail system, the at least one drive vehicle and trolley assembly can function as a conveyor belt for the storage containers. In another aspect, if the deployment area is a factory area, a production facility or another grid or rail system, direct access to an any of the latter areas which are outside the grid pattern is achieved. The multi trolley vehicle can move on the rail system, dedicated transport rails between the rail system and deployment area, on a double rail above or below the rail system or combinations thereof. The multi trolley vehicle can further transport storage containers from the deployment area to a storage position, i.e. a column in the grid. Thus, in an aspect where the deployment area is far away from the grid or rail system, the multi trolley vehicle provides for fast transfer of storage containers between the rail system and deployment area, and the deployment area and the grid or rail system.

If the deployment area is a factory area, it can be a service area where service may be conducted on the trolleys and or any of the drive vehicles manually or by machines.

The number of trolleys in one trolley assembly can easily be varied, and can be adapted based on the number of columns in the deployment area and or in a transfer zone, i.e. any number of trolley(s) can be added or subtracted from the trolley assembly thereby changing the number of trolleys making up the trolley assembly. One trolley can provide for lifting of more than one storage container and the trolley may occupy more than one row in the width and or length direction of the multi trolley vehicle. In the latter case, one trolley may be configured with more than one lifting devices, for example the number of lifting devices in one trolley corresponds to the number of cells occupied by the one trolley. Furthermore, the area occupied by one trolley may be smaller than, or substantially equal to, the size of a single cell. However, the occupied area of one trolley may also be larger than a single cell.

In an aspect, the automated storage and retrieval system further comprises a plurality of container handling vehicles which are operated on the rail system for retrieving storage containers from and storing storage containers in the storage columns, and for transporting the storage containers horizontally across the rail system. Furthermore, the rail system may comprise at least one transfer zone with underlying transfer columns for temporarily storing storage containers when in transit between the plurality of storage columns and the at least one deployment area, wherein the container handling vehicles are arranged to transport the storage containers between the storage columns and the at least one transfer zone.

Thus, the container handling vehicles are utilised to transport the storage containers between the storage columns and the transfer columns in the transfer zone.

The transfer zone is defined as a 2D area (in the Z and Y directions) on top of the rail system, i.e. the tracks, and the storage containers can be stored below the rail system or on top of the rail system from Z=<NUM> to Z=X, where X is number of the lowermost storage position in the grid.

As compared to providing more ports to alleviate a congestion problem, it is easy to increase the number of transfer columns in the transfer zone in the rail system. Furthermore, the transfer columns in the transfer zone(s) can be located inside the rail system, e.g. at a distance within the circumference of the rail system, thus allowing the container handling vehicles access to the transfer columns from the X and Y directions. A port, on the other hand, is normally located at the circumference of the rail system and, therefore, is normally only accessible from one direction. The transfer columns are preferably standard columns, and the location of the transfer zones with transfer columns in the rail system can be computer operated, thereby the position of the transfer zone and thereby the transfer columns can be programmed to be at the most convenient location, and can be continuously changed. The transfer columns can be a row of <NUM>, <NUM>, <NUM>, <NUM>, <NUM> ,<NUM>,. , <NUM> single cells in the rail system or more. A single cell is the area defined by two pairs of opposing bars in the X and Y directions.

One transfer zone comprises a plurality of neighboring individual transfer columns. The transfer columns can further be along more than one row, e.g. <NUM>, <NUM> or more parallel rows, either neighboring rows or not. The transfer zones, i.e. the transfer columns, can thus preferably be moved in the same direction as the direction of travel of the multi trolley vehicle(s). The location of the transfer zone(s), i.e. the transfer columns, is thus preferably always temporarily. This renders possible freeing up area on the rail system dependent on the operation of the container handling vehicles and or other vehicles moving on the rail system. For example, if a target bin is below, i.e. for example at Z=<NUM>, and a temporarily transfer column is at Z=<NUM>, the transfer zone, and thereby the transfer column, can easily be relocated such that a container handling device can access the container at Z=<NUM>.

Furthermore, this temporarily location of the transfer zones, allows for flexibility and provides maximum storage capacity in the grid system.

It may be advantageous if the transfer columns form a transfer zone and the at least one port form a port zone, wherein the transfer zone is adjacent the port zone. Alternatively, the transfer zone may be arranged at a distance from the port zone.

In an aspect, all moving devices in each trolley are non-motorized. In this aspect, the at least one drive vehicle is a master vehicle and all of the trolleys in the trolley assembly are slave vehicles.

In another aspect, one or more of the trolleys comprises motorized moving devices. To provide the trolleys with motorized moving devices can be advantageous in situations where a plurality of trolleys are used because the drag/push capacity of the drive vehicle(s) can be limited, i.e. insufficient to drag/push a plurality of trolleys.

In an aspect, the moving devices comprise wheels.

In another aspect, the moving devices comprise belts.

According to an aspect, the multi trolley vehicle is arranged to transport the storage containers between the at least one transfer zone and the at least one deployment area on the rail system, or in a plane located above or below the rail system. The transporting of the containers can be along at least a double rail, e.g. two parallel rails. By transporting the storage containers between the transfer columns in the transfer zone and the deployment area in a plane, for example on a double rail, which is located above or below the container handling vehicles, i.e. above or below the plane where the container handling vehicles travel across the rail system, any interference on the transfer of the storage containers between the transfer columns and the deployment area may have on the movement of the container handling vehicles will be minimized. The double rail may be suspended from the ceiling, be fastened to the walls, be supported on dedicated support legs, be mounted on the grid structure etc..

Each drive vehicle can occupy a single cell or more than one cell. Similarly, each trolley can occupy a single cell or more than one cell. Thus, the multi trolley vehicle may occupy one row, or may extend over more than one row, e.g. <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. <NUM> rows to increase the transport capacity. This means that according to one aspect of the invention the size of the at least one trolley may occupy a single cell or, alternatively in another aspect of the invention, one trolley may occupy more than one cell both in the direction of travel and/ or in the direction perpendicular to the direction of travel (i.e. in the X and or Y directions on the rail system). According to this latter aspect, each trolley can be provided with a plurality of lifting devices, e.g. elevators, for lifting and lowering storage containers between a column in the grid and a compartment for the storage containers in the trolley, which number of elevators corresponds to the number of cells occupied by the trolley. Furthermore, the drive vehicle(s) can occupy less rows than the connected trolleys, e.g. the drive vehicle(s) can occupy one row, whereas the trolley or trolley assembly can extend over <NUM> or more rows.

In an aspect, the system may comprise a second drive vehicle with motorized driving devices allowing self-propelled movement of the second drive vehicle in at least one of the first direction and/or the second direction, which second drive vehicle is connectable to a second end of the trolley assembly.

In an aspect, the first drive vehicle is arranged to transport the trolley assembly in a first direction, and the second drive vehicle is arranged to transport the trolley assembly in a second direction, which second direction is opposite the first direction.

In an aspect, the motorized moving devices of the first drive vehicle connected to the first end of the trolley assembly are configured to allow self-propelled, one-way movement along at least one of the first direction and/or the second direction and the motorized moving devices of the second drive vehicle connected to the second end of the trolley assembly are configured to allow self-propelled, one-way movement along an opposite direction of the at least one first direction and the second direction.

The connections between each trolley in the trolley assembly and any of the first drive vehicle and second drive vehicle may in an aspect allow a certain degree of movement between two adjacent trolleys and or the first or second drive vehicle in at least one direction, i.e. the connection is configured to allow movements along the direction of coupling corresponding to at least <NUM> % of the length of the respective coupling, thereby allowing the multi-trolley vehicle to follow curves in a track or go up a slope. Such connection may be mechanical connections, such as a pivot connection allowing some vertical and horizontal movement between adjacent trolleys or drive vehicles, a hook system, magnetic connection etc. A mechanical connection may e.g. be a single bracket, or two brackets connectable to each other, wherein the bracket(s) are fixed with fastening elements to adjacent trolleys or drive vehicles and provide some flexibility in the vertical direction, i.e. in the Z direction (if the driving direction is in the X or Y direction). As such, possible challenges related to irregularities on the rail system surface, such as particles, is greatly reduced.

The fastening elements may be screws or bolts or any other suitable fastening elements, or combinations thereof. In order to provide flexibility in the capacity and size of the multi trolley vehicle, the connection between the trolleys and any drive vehicles can be disconnectable, allowing easy addition of or, removal of, trolleys from the multi trolley vehicle.

In an aspect, a drive system in the at least first drive vehicle comprises a hub motor arranged within each of the moving devices. Alternatively, the drive system in the at least first, second or any additional drive vehicle may comprise an electric drive system, a direct drive system, a master wheel driving the driving elements as described in <CIT> a motor rotor driven by a stator, an electric system etc. An example of such motor rotor driven by an internal stator is shown in <CIT>.

If using wheels or belts as the moving devices, the complete motor can be arranged inside the external boundaries defined by the wheel (e.g. wheel rim etc.).

Furthermore, if one or more of the trolleys in the trolley assembly comprises motorized moving devices, the drive system for the motorized moving devices may comprise similar solutions as described above in relation to the at least first, second or any additional drive vehicle.

In an aspect, each trolley may comprise an open bottom end and a closed top end, and wherein a lifting device, such as an elevator, can be connected to the top end for lifting and lowering storage containers between a storage column and the compartment in the trolley.

The system may further comprise a port access vehicle, which port access vehicle comprises a plurality of vehicle sections which are connected one after the other in a train-like configuration, which vehicle sections each being configured to carry at least one storage container, and a plurality of container lifting and holding devices enabling simultaneous transport of a plurality of storage containers between the rail system and the deployment area, and wherein the port access vehicle is arranged to transport the storage containers between the rail system and the at least one deployment area in a plane located above the rail system. The train-like configuration allows for the port access vehicle to be easily adapted to changing conditions in the grid or rail system. The port access vehicle may be operated on the rail system, e.g. be arranged to travel along the rail system of the grid. Alternatively, the port access vehicle may be operated on a monorail or double rail arranged in a parallel horizontal plane above the rail system.

In an aspect, each trolley may comprise a closed bottom end and an open top end for receiving storage containers from above. This is rendered possible by for example allowing the trolley assembly to cooperate with one or more stationary lifting arrangements, using e.g. a port access vehicle, or using another multi trolley vehicle operating in the same X and Y rows but in different Z locations, i.e. arranged directly above the trolleys. It may be advantageous if the port access vehicle comprises a first lifting and transfer device arranged to carry a storage container from one of the transfer columns to the trolleys.

In order to increase the capacity of the port access vehicle, it may be advantageous if the port access vehicle comprises a plurality of container lifting and holding devices enabling simultaneous transport of a plurality of storage containers between the transfer columns in the transfer zone and the at least one port.

The invention further relates, as per claim <NUM>, to the use of a multi trolley vehicle operable on an automated storage and retrieval system as defined above for moving storage containers between stacks within a grid pattern formed by horizontal first and second set of parallel tracks and a deployment area, which deployment area provides direct access to an area outside the grid pattern formed by first and second sets of parallel tracks, wherein the multi trolley vehicle is configured to move on the rail system above the storage columns and comprises a trolley assembly comprising a plurality of trolleys coupled to each other along at least one of a first direction and second direction, where.

It is further described a multi trolley vehicle comprising a trolley assembly comprising a plurality of trolleys coupled to each other along at least one of a first direction and second direction, where.

In this latter multi trolley vehicle each trolley comprises a closed bottom end and an open top end for receiving storage containers from above. This is rendered possible by for example allowing the trolley assembly to cooperate with one or more stationary lifting arrangements, using e.g. a port access vehicle, container handling vehicles or using another multi trolley vehicle operating in the same X and Y rows but in different Z locations, i.e. arranged directly above the trolleys. It may be advantageous if the port access vehicle comprises a first lifting and transfer device arranged to carry a storage container from one of the transfer columns or in port zones lifting or lowering storage containers onto and or off from the trolleys. Thus, it is clear that this multi trolley vehicle can function as a conveyor belt, for example in the port zone, rendering the use of traditional conveyor belts in this area superfluous.

In an aspect, the container volume of the trolley comprises a compartment for fully containing storage containers within a body of the trolley or on the side of the body (cantilever construction).

In an aspect, the multi trolley vehicle further comprises a second drive vehicle with motorized driving devices allowing self-propelled movement of the second drive vehicle in at least one of the first direction and the second direction, which second drive vehicle is connectable to a second end of the trolley assembly.

The invention further relates to method of operating an automated storage and retrieval system as defined in claim <NUM>, the automated storage and retrieval system comprising:
a rail system comprising a first set of parallel tracks arranged in a horizontal plane and extending in a first direction, and a second set of parallel tracks arranged in the horizontal plane and extending in a second direction which is orthogonal to the first direction, which first and second sets of tracks form a grid pattern in the horizontal plane comprising a plurality of adjacent grid cells, each comprising a grid opening defined by a pair of neighboring tracks of the first set of tracks and a pair of neighboring tracks of the second set of tracks; and a plurality of stacks of storage containers arranged in storage columns located beneath the rail system, wherein each storage column is located vertically below a grid opening; which method comprises:.

In an aspect, the method further comprises:.

In the following description, numerous specific details are introduced by way of example only to provide a thorough understanding of embodiments of the claimed system and method. One skilled in the relevant art, however, will recognize that these embodiments can be practiced without one or more of the specific details, or with other components, systems, etc. In other instances, well-known structures or operations are not shown, or are not described in detail, to avoid obscuring aspects of the disclosed embodiments.

Following drawings are appended to facilitate the understanding of the invention;.

In the drawings, like reference numerals have been used to indicate like parts, elements or features unless otherwise explicitly stated or implicitly understood from the context.

Furthermore, even if some of the features are described in relation to the system only, it is apparent that they are valid for the method and the multi trolley vehicle as well, and vice versa, i.e. any features described in relation to the method only are also valid for the system and multi trolley vehicle.

<FIG> is a top view of a cell of a grid <NUM> with a rail system <NUM> of the automated storage and retrieval system. The grid <NUM> comprises a framework structure <NUM> comprising a plurality of upright members <NUM> (see <FIG>) and a plurality of horizontal members <NUM> which are supported by the upright members. As is known in the art, the upright and horizontal members may typically be made of metal, e.g. extruded aluminium profiles. The upper surface of the grid <NUM> has a rail system <NUM>. The rail system <NUM> comprises a first set of parallel tracks <NUM> arranged in a horizontal plane P and extending in a first direction X, and a second set of parallel tracks <NUM> arranged in the horizontal plane P and extending in a second direction Y which is orthogonal to the first direction X. The first and second sets of tracks <NUM>, <NUM> form a grid pattern in the horizontal plane P comprising a plurality of adjacent grid cells, each comprising a grid opening <NUM> defined by a pair of neighboring tracks 10a, 10b of the first set of tracks <NUM> and a pair of neighboring tracks 11a, 11b of the second set of tracks <NUM>. The example grid openings <NUM> in <FIG> are part of the overall rail system <NUM> (see <FIG>).

A general description of an automated storage and retrieval system according to the invention will now be discussed in more detail with reference to <FIG>. The horizontal members <NUM> comprise a rail system <NUM> arranged in a grid pattern across the top of the storage columns, on which rail system <NUM> a plurality of container handling vehicles <NUM> are operated. The rail system <NUM> comprises a first set of parallel rails <NUM> arranged to guide movement of the container handling vehicles <NUM> in a first direction X across the top of the frame structure <NUM>, and a second set of parallel rails <NUM> arranged perpendicular to the first set <NUM> to guide movement of the container handling vehicles <NUM> in a second direction Y that is perpendicular to the first direction X. In this way, the rail system <NUM> defines grid columns <NUM> in the horizontal X-Y plane, above which grid columns <NUM> the container handling vehicles <NUM> can move horizontally in the X and Y directions. Consequently, the horizontal area of a grid column <NUM>, i.e. along the X and Y directions, may be defined by the distance between adjacent rails <NUM> and <NUM>, respectively (details in <FIG>). Consequently, the rail system <NUM> allows the container handling vehicles <NUM> to move horizontally in the X-Y plane between different grid locations, where each grid location is associated with a grid column <NUM>.

The container handling vehicles <NUM> may be of any type known in the art, e.g. any one of the automated container handling vehicles <NUM> discussed in relation to <FIG>, <FIG>. It may be advantageous if each container handling vehicle <NUM> comprises a centrally located storage space for receiving and stowing a storage container <NUM> when transporting the storage container horizontally across the rail system <NUM>, and a footprint, i.e. an extent in the X and Y directions, which is generally equal the horizontal extent of a grid column <NUM>. This will allow a container handling vehicle <NUM> to transport a storage container above a row of grid columns even if another container handling vehicle <NUM> occupies a location above a grid column neighboring the grid column row along which the first container handling vehicle is traveling. Alternatively, container handling vehicles of cantilever construction can also be used.

In the disclosed embodiment of <FIG>, the grid <NUM> or rail system <NUM> comprises a storage zone <NUM>, two port zones <NUM> and two transfer or buffer zones <NUM>. Each port zone <NUM>, which is, for example, three grid cells wide in the X direction and seven grid cells long in the Y direction, comprises ports <NUM>, <NUM> where storage containers can be transferred out of or into the grid <NUM>. Each transfer zone <NUM>, the function of which is discussed in more detail below, is three grid cells wide (rows denoted <NUM>, <NUM>, <NUM> in the X direction) and <NUM> grid cells long (in the Y direction) in the example shown. The storage zone <NUM>, which makes up the rest of the rail system <NUM>, comprises storage columns <NUM> in which storage containers or bins <NUM> can be stacked one on top of another to form stacks <NUM>.

<FIG> show example of a system according to the invention. <FIG> shows a first drive vehicle <NUM> connected to a first end of a trolley assembly <NUM> comprising six trolleys <NUM>' connected to each other and a second drive vehicle <NUM> connected to an opposite second end of the trolley assembly <NUM>. This setup is generally denoted as a 'multi trolley vehicle' with reference number <NUM>. However, the multi trolley vehicle <NUM> in the simplest form, may have only one drive vehicle and a trolley assembly <NUM> comprising one trolley <NUM>'. <FIG> is a side view of the system of <FIG>. <FIG> is an end view of the system of <FIG>, while <FIG> is a top view of <FIG>.

It is disclosed an automated storage and retrieval system comprising a three-dimensional grid <NUM> comprising a plurality of storage columns <NUM> in which storage containers are stored one on top of another in vertical stacks (see <FIG> for detailed view of storage containers <NUM> and stacks <NUM>). Each trolley <NUM>' comprises moving devices, such as a first set of wheels <NUM>, <NUM>, and are arranged to transport the storage containers <NUM>. The first and second drive vehicles <NUM>, <NUM> comprise motorized moving devices, in <FIG> shown as motorized first set of wheels <NUM>, <NUM>. Preferably, the first drive vehicle <NUM> is arranged to transport the trolley assembly <NUM> in a first direction, and the second drive vehicle <NUM> is arranged to transport the trolley assembly <NUM> in a second direction, which second direction is opposite the first direction. However, in cases with only one drive vehicle <NUM>, <NUM>, the one drive vehicle can drive in both directions (i.e. both pushing and pulling the trolley assembly <NUM>). In yet another aspect the drive vehicle(s) <NUM>, <NUM> and trolley assembly <NUM> can drive in both X and Y directions. According to this latter aspect, the drive vehicles and trolleys can be provided with two set of wheels, one set for each X and Y directions where the set of wheels not used can be temporarily lifted up from contact with the rails, as is known in the art.

The first and second drive vehicles <NUM>, <NUM> are connectable to a first end of the trolley assembly <NUM> via connections <NUM>. Alternatively, the drive vehicle(s) <NUM>, <NUM> can be connected partway or midway within the trolley assembly (<NUM>). The connection <NUM> between each trolley <NUM>' in the trolley assembly <NUM> and any of the first drive vehicle <NUM> and second drive vehicle <NUM> allows a certain degree of movement between two adjacent trolleys <NUM>' and or the first or second drive vehicle <NUM>, <NUM>, in at least one direction. In the disclosed embodiment it is shown a single bracket which is connected to respective adjacent trolleys <NUM>' and/or drive vehicle <NUM>, <NUM>. The multi trolley vehicle <NUM> is arranged to transport the storage containers <NUM> between a storage column <NUM> (exemplified as a transfer column <NUM> in a transfer zone <NUM> and at least one deployment area (see <FIG> for illustrations of different deployment areas).

The transfer columns <NUM>, <NUM> in the transfer zones <NUM> are preferably standard columns <NUM>, and the location of the transfer columns <NUM>, <NUM> in the grid or on the rail system <NUM> can be computer operated, thereby the position of the transfer zone <NUM>, and thus the transfer columns <NUM>, <NUM>, can be programmed to be at the most convenient location, and can be continuously changed. The transfer columns <NUM>, <NUM> can further be along more than one row, e.g. <NUM>, <NUM> or more parallel rows, either neighboring rows or not. The transfer zone <NUM>, and thus the transfer columns <NUM>, <NUM>, can thus preferably be moved along the same row as the direction of travel of the at least first vehicle <NUM>, <NUM> and trolley assembly <NUM>, i.e. the multi trolley vehicle <NUM>. The location of the transfer zones and transfer columns <NUM>, <NUM> are thus preferably always temporarily. This renders possible freeing up area in the grid, dependent on the operation of the container handling vehicles <NUM> and or other vehicles moving on the rail system <NUM>.

The multi trolley vehicle(s) <NUM> is arranged to travel rectilinearly on or above the rail system <NUM> along at least one row <NUM> of said grid columns. Each drive vehicle <NUM>, <NUM> can occupy a single cell or more than one cell in the direction perpendicular to the driving direction. Similarly, each trolley <NUM>' can occupy a single cell or more than one cell in the direction perpendicular to the driving direction. The drive vehicle(s) <NUM>, <NUM> can occupy more or less rows than the trolleys <NUM>'.

As is disclosed in <FIG>, the trolleys <NUM>' are shown as having equal extension in the travel direction of the multi trolley vehicle <NUM> as one single cell, i.e. the area occupied by one trolley <NUM>' is not extending outside a single cell. In this setup, neighboring trolleys <NUM>' may pick up storage containers <NUM> from neighboring storage columns <NUM>.

<FIG> is a perspective view of an embodiment of the invention where a multi trolley vehicle <NUM> having a first and second drive vehicle <NUM>, <NUM> connected at each end to a trolley assembly <NUM> moves on a double rail <NUM> above the rail system <NUM> where container handling vehicles <NUM> operates.

<FIG> is a side view of the embodiment in <FIG>.

<FIG> are examples of an embodiment of the invention where storage containers <NUM> are lowered down onto the trolleys <NUM>' in the trolley assembly <NUM> by container handling vehicles <NUM> or another, i.e. an upper multi trolley vehicle <NUM> (<FIG>), which container handling vehicles <NUM> and multi trolley vehicle <NUM> operate on a rail system <NUM> located above a double rail <NUM> where the multi trolley vehicle <NUM> operates. <FIG> is a perspective view, while the two figures on <FIG> are, respectively, in the direction of travel of the multi trolley vehicle <NUM> (to the left), and a side view of <FIG> (to the right). As is disclosed in <FIG>, each trolley <NUM>' in the lower trolley assembly <NUM> may either comprise open-top boxes (see details in <FIG>, the three boxes closest to the second drive vehicle <NUM>) which can receive storage containers <NUM> from above or, alternatively, the trolleys <NUM>' in the trolley assembly <NUM> can have a receiving surface in the form of a platform or bed possibly provided with connecting elements and/or friction elements for receiving the storage containers <NUM> (see details in <FIG>, the three trolleys <NUM>' closest to the first drive vehicle <NUM>).

Instead of transporting storage containers <NUM> away from the rail system, the multi trolley vehicle <NUM> may transport storage containers <NUM> to the rail system, where storage handling vehicles <NUM>, or other devices with lifting devices, can retrieve the storage containers <NUM> from the trolley assembly <NUM> and place them in dedicated storage columns <NUM> in the grid <NUM>.

As an alternative to receiving storage containers from the depicted storage handling vehicles <NUM> in <FIG>, other vehicles operating on the rail system <NUM>, such as another multi trolley vehicle <NUM> (<FIG>) or a port access vehicle (see for example <FIG>), may lower or retrieve the storage containers <NUM> to and from the trolleys <NUM>'.

In the embodiment of <FIG>, it is clear that the multi trolley vehicle <NUM> can function as a conveyor belt, for example in the port zone, rendering the use of traditional conveyor belts in this area superfluous. This is rendered possible by for example allowing the trolley assembly <NUM> to cooperate with one or more lifting arrangements, for example the container handling vehicles <NUM> or another multi trolley vehicle <NUM> where the trolleys comprise lifting devices, the port access vehicle <NUM>, any vehicle located in a horizontal plane above where disclosed lower multi trolley vehicle <NUM> operates. If another multi trolley vehicle <NUM> is used, this multi trolley vehicle <NUM> (i.e. the disclosed upper multi trolley vehicle <NUM> in <FIG>) preferably operates in the same X and Y rows but in different Z locations as the disclosed lower multi trolley vehicle <NUM>. e.g. operating in the same plane as the disclosed container handling vehicles and the upper multi trolley vehicle <NUM> operate (as disclosed in <FIG>). With reference to <FIG>, the multi trolley vehicle <NUM> may occupy one row, or may extend over more than one row <NUM>, e.g. <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. <NUM> rows to increase the transport capacity. Thus, the size of the at least one trolley <NUM>' may occupy a single cell or one trolley <NUM>'may occupy more than one cell both in the direction of travel and/or in the direction perpendicular to the direction of travel (i.e. in the X and/or Y directions on the rail system <NUM>). In the latter case, each trolley <NUM>' can be provided with a plurality of lifting devices, e.g. elevators (for example as disclosed in <FIG> or elevators connected to a top end of the trolley <NUM>' for lifting and lowering storage containers <NUM> between a column in the grid or rail system <NUM> and volume compartment for fully containing a storage container in the trolley <NUM>'), for lifting and lowering storage containers <NUM> between a column <NUM> in the grid <NUM> and the trolley <NUM>', which number of lifting devices correspond to the number of cells occupied by the trolley <NUM>'.

The double rail <NUM> is disclosed supported on dedicated support legs <NUM>, but may also be suspended from the ceiling, be fastened to the walls, be mounted on the grid structure etc. In general, transporting the storage containers <NUM> between the transfer columns <NUM>, <NUM> or any other storage column <NUM> and the deployment area in a substantially horizontal plane, for example on a double rail <NUM>, which is located above or below the container handling vehicles <NUM>, i.e. above or below the plane where the container handling vehicles <NUM> travel across the grid <NUM>, any interference on the transfer of the storage containers <NUM> between the transfer columns <NUM>, <NUM> and the deployment area may have on the movement of the container handling vehicles <NUM> will be minimized.

Not including the port zones <NUM>, the grid <NUM> in the example of <FIG> is <NUM> cells wide in the X direction and <NUM> cells long in the Y direction. In the Z direction (cf. <FIG>), the grid <NUM> may have a height of five cells. It is understood, however, that the grid <NUM>, in principle, can be of any size. In particular, it is understood that grid <NUM> can be considerably wider and/or longer than disclosed in <FIG> and <FIG>. For example, the grid may have a horizontal extent of more than 600x600 grid cells. Also, the grid <NUM> can be considerably deeper than disclosed in <FIG>. For example, a grid may be more than <NUM> grid cells deep (in the Z direction). In the embodiment of <FIG>, multi trolley vehicles <NUM> with drive vehicles <NUM>, <NUM> and trolley assemblies <NUM> can travel along any one or more of rows <NUM>, <NUM>, <NUM> in the transfer zone <NUM>, and the transfer zone <NUM> can be e.g. any one of rows <NUM>, <NUM> and or <NUM> (or alternatively additional rows). In the specific embodiment of <FIG>, the transfer zone <NUM> to the left in the Figure, i.e. denoted G1, discloses a multi trolley vehicle <NUM> which is three cells wide (X-direction) and seven cells long (Y-direction). Thus, the multi trolley vehicle <NUM> serves all three rows <NUM>, <NUM>, <NUM> in transfer zone <NUM>. In transfer zone <NUM> to the right in the Figure, i.e. denoted G2, there are three multi trolley vehicles <NUM> serving the transfer zone <NUM>, with one multi trolley vehicle <NUM> in each of the rows <NUM>, <NUM>, <NUM>, including: in row <NUM> a multi trolley vehicle <NUM> which is one cell wide and nine cells long, in row <NUM> a multi trolley vehicle <NUM> which is one cell wide and <NUM> cells long, and in row <NUM> a multi trolley vehicle <NUM> which is one cell wide and <NUM> cells long. It is also possible that the multi trolley vehicle <NUM> could be one cell long and <NUM> or more cells wide.

Alternatively, the multi trolley vehicles <NUM> with at least one drive vehicle <NUM>, <NUM> and trolley assembly <NUM> can travel along rows <NUM> and <NUM>, while a port access vehicle <NUM> (features of the port access vehicle <NUM> explained in greater detail below) can be arranged to travel, or be fixed at particular columns, along row <NUM> for cooperation with the multi trolley vehicles <NUM>.

Each transfer zone <NUM> comprises transfer columns <NUM>, <NUM> arranged to temporarily hold storage containers <NUM> when in transit between the storage zone <NUM> and the port zones <NUM>. The transfer columns include drop-off columns <NUM> where the container handling vehicles <NUM> can drop off storage containers retrieved from the grid <NUM>, and pick-up columns <NUM> where the container handling vehicles <NUM> can pick up storage containers <NUM> to be stored in the grid <NUM>.

The drop-off columns <NUM> are arranged in a row <NUM> extending in the Y direction from the exit ports <NUM>. The pick-up transfer columns <NUM> are arranged in a row <NUM> extending in the Y direction from the entry ports <NUM>. An intermediate column row of grid columns <NUM> is positioned between rows <NUM> and <NUM>. In other words, the drop-off columns <NUM> and the pick-up columns <NUM> are separated by the intermediate column row <NUM>.

In the disclosed embodiment, the drop-off columns <NUM> and the pick-up columns <NUM> occupy positions Y=<NUM> to Y=<NUM> in each row <NUM> and <NUM>. Consequently, the drop-off columns <NUM> and the pick-up columns <NUM> are <NUM> grid cells long, i.e. they extend <NUM> grid cells into the transfer zone <NUM>. Since the number of drop-off and pick-up columns <NUM>, <NUM> is larger than the number of ports <NUM>, <NUM>, the likelihood of a container handling vehicle <NUM> not finding a vacant drop-off column <NUM> where it can deliver a storage container is low.

<FIG> also discloses an example of a port zone <NUM> in more detail. Each port zone <NUM> comprises seven exit ports or exit port columns <NUM> through which the storage containers <NUM> can be brought out of the grid <NUM> to be accessed from outside of the grid <NUM>. Each port zone <NUM> also comprises entry ports or entry port columns <NUM> through which storage containers <NUM> can be brought into the grid <NUM> to be stored in the storage columns <NUM>. An access and transfer system <NUM> is arranged for transporting storage containers between the ports <NUM>, <NUM> and an access station <NUM>, which in the disclosed embodiment is a picking and stocking station. The access and transfer system <NUM> comprises a first conveyor <NUM> which is arranged underneath the exit ports <NUM> to transport storage containers from the exit ports <NUM> to the access station <NUM>, and a second conveyor <NUM> which is arranged underneath the entry ports <NUM> to transport storage containers from the access station <NUM> to the entry ports <NUM>. The rail system <NUM> extends into the port zones <NUM> of the grid <NUM>.

Port access vehicles are operated above the grid <NUM> for transferring storage containers <NUM> between the transfer zones <NUM> and the port zones <NUM>. As will be discussed in more detail in the following, each port access vehicle <NUM> is arranged to transfer storage containers <NUM> above the operating plane of the container handling vehicles <NUM>, i.e. in a plane above the operating space of the container handling vehicles <NUM> and any multi trolley vehicles <NUM>, thus allowing the port access vehicle <NUM> to transfer a storage container <NUM> over a drop-off or pick-up transfer column <NUM>, <NUM> even if a container handling vehicle <NUM> or multi trolley vehicle <NUM> occupies the grid location above that drop-off or pick-up transfer column <NUM>, <NUM>. Consequently, multi trolley vehicles <NUM> and container handling vehicles <NUM> can be dropping off or picking up storage containers from drop-off or pick-up transfer columns <NUM>, <NUM> while the port access vehicle <NUM> simultaneously transfers other storage containers <NUM> between the transfer zone <NUM> and the port zone <NUM> above the container handling vehicles <NUM>.

A port access vehicle <NUM> which can form part of the system will now be discussed in more detail with reference to <FIG>, <FIG>.

The port access vehicle <NUM> may operate along the grid columns in row <NUM> (cf. <FIG>), i.e. along a row of grid columns which extend into the grid from the port zone <NUM>. The port access vehicle <NUM> may comprise a plurality of vehicle sections <NUM> which are connected in a train-like configuration, i.e. one after the other (e.g. cf. Each vehicle section <NUM> comprises a vehicle body <NUM> which has a footprint which generally corresponds to the lateral extension of a grid column <NUM>, thus allowing the port access vehicle to pass between container handling vehicles <NUM> or multi trolley vehicles <NUM> which are dropping off or picking up storage containers in the transfer zone. At the lower end of the vehicle body <NUM>, a set of wheels <NUM> is mounted and configured to allow the vehicle section <NUM> to travel on the rail system <NUM> in the Y direction along row <NUM>.

In the train of vehicle sections <NUM> making up the port access vehicle <NUM>, the set of wheels <NUM> of at least one the vehicle sections <NUM> is motorized in order to propel the port access vehicle <NUM>.

The vehicle section <NUM> comprises a horizontal bar or frame <NUM> which is mounted to the top of the vehicle body <NUM> and extends horizontally from both sides of the vehicle body <NUM> orthogonal to the dedicated direction of travel of the vehicle section <NUM>, which dedicated direction of travel is defined by the set of wheels <NUM>. In other words, when in operation on the rail system <NUM> or e.g. on a monorail above the rail system <NUM>, the horizontal bar <NUM> extends in the X direction (e.g. cf. On both sides of the vehicle body <NUM>, the horizontal bar <NUM> supports a container lifting and holding device <NUM>, <NUM>. Each lifting and holding device <NUM>, <NUM> comprises a container gripping device <NUM>, <NUM>, which can be lowered from the horizontal bar <NUM> to grip and hold a storage container <NUM>. The gripping devices <NUM>, <NUM> can be individually lowered in order to pick up and drop off storage containers independently of each other.

The lifting and holding devices <NUM>, <NUM> are arranged to hold storage containers in a raised, holding position when the port access vehicle <NUM> transports the storage containers <NUM> between the transfer zone <NUM> and the port zone <NUM>. The vehicle body <NUM> of the vehicle sections <NUM> has a vertical extension which is sufficient to allow the lifting and holding devices <NUM>, <NUM> to hold the storage containers <NUM> in a holding position which is above the operating space of the container handling vehicles (e.g. cf.

With reference to <FIG>, instead of equipping the trolleys <NUM>' with lifting devices or elevators, each trolley <NUM>' may comprise a closed bottom end and an open top end (see <FIG>, <FIG>) for receiving storage containers <NUM> from above. This is rendered possible by for example allowing the trolley assembly <NUM> to cooperate with one or more lifting arrangements, for example the port access vehicle <NUM>, or using another multi trolley vehicle <NUM> located in the same X and Y rows but in different Z locations, i.e. arranged directly below or above. It is advantageous if the lifting arrangement comprises a first lifting device arranged to carry a storage container <NUM> from one of the transfer columns <NUM>, <NUM> and position it in or on the at least one trolley <NUM>' for transport to the deployment area, and a second lifting arrangement, e.g. another or the same port access vehicle <NUM> or a stationary lifting arrangement, arranged at the deployment area for picking up the storage container <NUM> from the trolley <NUM>'. Similarly, the system can be adapted to transport the storage container <NUM> from the deployment area to any one transfer columns <NUM>, <NUM> in the transfer zone <NUM>. The multi trolley vehicle <NUM> can be used for transporting the storage containers <NUM> to a deployment area, for example a port <NUM>, where the same or alternatively another port access vehicle <NUM> can lift the storage containers <NUM> from the trolleys <NUM>' and place them in respective columns or ports etc. The port access vehicle <NUM> is then either moved along row <NUM> or is stationary arranged in the deployment area or a factory area or production facility <NUM> (see <FIG>), e.g. the port zone <NUM>. When the multi trolley vehicle <NUM> arrives in the port zone <NUM>, the port access vehicle <NUM> lifts the storage containers <NUM> from above and lowers the storage container into a grid column which is directly into an exit port column <NUM> or adjacent an exit port column <NUM>. The target storage container is then lowered into exit port column <NUM> and positioned on conveyor <NUM> (see <FIG>), which transports the target storage container <NUM> to the access station <NUM>. Instead of a conveyor, it is possible, as discussed above, to use at least one multi trolley vehicle <NUM> to transport the storage containers <NUM> to the access station <NUM>. Furthermore, using a multi trolley vehicle <NUM> instead of e.g. a conveyor belt results in a significantly longer possible operating distance between the exit port column <NUM> in the grid and the access station <NUM> (i.e. the access station <NUM> does not have to be close to the exit port column <NUM> as the multi trolley vehicle render possible faster and longer possible transport distance between the exit port column <NUM> and the access station <NUM> than is possible by using a conveyor belt) as well as a possibly faster transfer of storage containers.

With reference to <FIG>, once accessed at the access station <NUM>, the target storage container is transferred back into the grid <NUM> to once again be stored in a storage column <NUM> in the storage zone <NUM>. This operation is essentially the reversal of the above-discussed operation of fetching a storage container from the grid and involves:.

The port access vehicle <NUM> may be operated on the grid, e.g. be arranged to travel along the rail system <NUM> of the grid. However, as disclosed in <FIG> and <FIG>, the port access vehicle <NUM> may be operated on a monorail <NUM> (or other form of overhead rail system) arranged in a horizontal plane above the rail system <NUM> and the multi trolley vehicle <NUM> can be operated on the rail system <NUM>.

When the container handling vehicle <NUM> has positioned the target storage container in the drop-off transfer column <NUM> and left the transfer zone <NUM>, e.g. to retrieve another storage container <NUM> from the grid <NUM>, the multi trolley vehicle <NUM> is moved along its dedicated row, i.e. row <NUM>, <NUM> or <NUM> and positioned with one of its trolleys <NUM>' located above the grid column which is at the same drop-off transfer column <NUM> in which the container handling vehicle <NUM> has positioned the target storage container. One of the trolleys <NUM>' then retrieves the target storage container <NUM> from the drop-off transfer column <NUM> by lowering the lifting device, gripping the target storage container and raising it into the compartment in the trolley. Similarly, if the footprint of the trolleys <NUM>' occupy maximum one cell the other trolleys <NUM>' can pick up storage containers from neighboring columns in the same row(s) in the transfer zone <NUM>. The multi trolley vehicle <NUM> is then moved to e.g. port zone <NUM> where the trolleys <NUM>' lower the storage containers <NUM> into exit port column(s) <NUM> and positions the storage container(s) <NUM> on for example a conveyor <NUM> or a multi trolley vehicle <NUM>, which transports the target storage container(s) to the access station <NUM>.

In the transfer zones <NUM>, the storage containers <NUM> are advantageously stored in the uppermost layer of the grid, i.e. in the layer identified as Z=<NUM>. This will minimize the distance the gripping devices of the container handling vehicles <NUM>, the trolleys <NUM>' in the multi trolley vehicle <NUM> and port access vehicle <NUM> needs travel when dropping off and picking up storage containers <NUM> in the transfer zone <NUM>, which will allow for rapid turnaround of the storage containers temporarily stored therein.

In order to allow the storage containers to be temporarily stored in the uppermost layer in the respective transfer columns, each transfer column may comprise stopping devices (not shown), e.g. clamps attached to the upright members <NUM> surrounding each transfer column, which clamps prevent the storage container from being lowered into the transfer column beyond level Z=<NUM>. Of course, the clamps can be attached to the upright members deeper down the transfer column, thus allowing the storage containers to be temporarily stored at deeper levels than Z=<NUM>. Alternatively, this temporary storage can be achieved by stacking a plurality of empty storage containers up to the location Z=<NUM> in all of the storage columns <NUM> defined by the transfer zone <NUM>.

The storage containers can be temporarily stored at different levels in different transfer columns. Also, in some applications it may be advantageous to simultaneously store more than one storage container in a transfer column. However, in such an application the trolley <NUM>' needs to be configured to carry out a digging operation in order to retrieve a storage container temporarily stored below another temporarily stored storage container.

Due to the modular character of the multi trolley vehicle <NUM>, the multi trolley vehicle <NUM> can be easily adapted to different transfer zone sizes and/or deployment area configurations by adding or removing trolleys <NUM>'. Consequently, the multi trolley vehicle <NUM> can be configured to simultaneously transfer a plurality of storage containers between the transfer zone <NUM> and the deployment area. For example, when traveling from the transfer zone <NUM> to the port zone <NUM>, each trolley <NUM>' can be employed to carry a storage container. Likewise, when traveling from the port zone <NUM> to the transfer zone <NUM>, each trolley <NUM>' can be employed to carry a storage container.

<FIG> is a top view of a grid <NUM> of an automated storage and retrieval system according to the invention where possible positions and shapes of transfer zones <NUM> and port zones <NUM> are indicated. Areas shaded dark grey indicate transfer zones <NUM> and areas shaded light grey indicate port zones <NUM>. Each port zone comprises ports <NUM>, <NUM> and each transfer zone <NUM> comprises transfer columns arranged in rows. In the disclosed example each transfer zone <NUM> is associated with at least one port zone <NUM>. White grid cells indicate storage columns <NUM> defining the grid's storage zone <NUM>. Automated container handling vehicles <NUM> are operated on the grid <NUM> or rail system <NUM> as previously discussed, i.e. to transport storage containers <NUM> between the storage columns <NUM> and the transfer zones <NUM> and are shown as black grid cells. Double arrows extending along the port and transfer zones indicate the operation of port access vehicle operating as previously discussed, i.e. to transport the storage containers between the transfer zones <NUM> and the port zones <NUM>. Dark grey grid cells indicate multi trolley vehicles <NUM> operating on the grid between the transfer zone <NUM> and the port zone <NUM>.

The region labelled A shows a transfer zone <NUM> with a non-rectangular shape. Since the length of the transfer zone <NUM> in the Y direction exceeds three rows, the port access vehicle <NUM> serving the transfer zone <NUM> should be configured with bars or frames extending or being extendable in the Y direction in order to access the outermost drop-off and pick-up transfer columns. The bars may for example be telescopically extendible bars. The region labelled B shows a squared-shaped transfer zone <NUM> which may be accessed by two port access vehicles, one operating in the X direction and one in the Y direction. The region labelled C shows a configuration where the port zone <NUM> does not form an extending portion of the grid <NUM>. The region labelled D shows a transfer zone <NUM> which is located adjacent the grid circumference.

<FIG> show examples of different deployment areas. <FIG> shows a deployment area being another grid system <NUM> (for example another storage system or warehouse) with a double rail <NUM> between the grid or rail systems <NUM>, <NUM>. Another double rail (not shown in the Figure) can be arranged at another level than the disclosed double rail <NUM>. One or more multi trolley vehicles <NUM> (indicated in shaded grey on the Figure) can operate on the double rail <NUM>. <FIG> shows the deployment areas being two other storage/warehouse systems with dedicated grid systems <NUM> and with a double rail between the different grid systems <NUM> in the different storage systems. <FIG> shows the deployment area being a factory area or production facility <NUM> where the multi trolley vehicles <NUM> are configured to drive on a double rail formed as a loop between the grid or rail system <NUM>, <NUM> and the factory area or production facility <NUM>. The arrow A in <FIG> indicates the direction of travel along the loop <NUM> for the multi trolley vehicles <NUM>. If it is a single double rail between the grid system <NUM> and the factory area or production facility <NUM>, it is advantageous that the different multi trolley vehicles <NUM> travel in the same direction to avoid collision etc. However, if there are multiple rails either on the same level or at different levels the different multi trolley vehicles <NUM> can travel in both directions on the rail(s). It shall be noted that the relative large size of the multi trolley vehicles <NUM> compared to the rails in <FIG> are for illustrative purposes only and it is clear that the multi trolley vehicle <NUM> can be of less width (e.g. the same width as the rail).

In the preceding description, various aspects of an automated storage and retrieval system according to the invention have been described with reference to the illustrative embodiment. However, this description is not intended to be construed in a limiting sense. Various modifications and variations of the illustrative embodiment, as well as other embodiments of the system, which are apparent to persons skilled in the art, are deemed to lie within the scope of the present invention as defined by the following claims.

Claim 1:
An automated storage and retrieval system comprising:
- a rail system (<NUM>) comprising a first set of parallel tracks (<NUM>) arranged in a horizontal plane (P) and extending in a first direction (X), and a second set of parallel tracks (<NUM>) arranged in the horizontal plane (P) and extending in a second direction (Y) which is orthogonal to the first direction (X), which first and second sets of tracks (<NUM>,<NUM>) form a grid pattern in the horizontal plane (P) comprising a plurality of adjacent grid cells, each comprising a grid opening (<NUM>) defined by a pair of neighboring tracks (10a,10b) of the first set of tracks (<NUM>) and a pair of neighboring tracks (10a,10b) of the second set of tracks (<NUM>); and
- a plurality of stacks (<NUM>) of storage containers (<NUM>) arranged in storage columns (<NUM>) located beneath the rail system (<NUM>), wherein each storage column (<NUM>) is located vertically below a grid opening (<NUM>);
characterised in that the system further comprises:
a multi trolley vehicle (<NUM>) for transporting storage containers (<NUM>) between the storage columns (<NUM>) and at least one deployment area (<NUM>, <NUM>, <NUM>), which deployment area (<NUM>, <NUM>, <NUM>) provides direct access to an area outside the grid pattern formed by the first and second sets of tracks (<NUM>, <NUM>), the multi trolley vehicle (<NUM>) comprising:
a trolley assembly (<NUM>) comprising a plurality of trolleys (<NUM>') coupled to each other along at least one of the first direction (X) and second direction (Y), where
each trolley (<NUM>') provides at least one container volume for storing at least one of the storage containers (<NUM>) and where
each trolley (<NUM>') comprises moving devices (<NUM>, <NUM>) allowing movement of the trolley assembly (<NUM>) in at least one of the first direction (X) and/or the second direction (Y), and where
at least one of the trolleys (<NUM>') comprises non-motorized moving devices (<NUM>, <NUM>), and
a first drive vehicle (<NUM>) coupled to the trolley assembly (<NUM>), the first drive vehicle (<NUM>) comprising motorized moving devices (<NUM>, <NUM>) allowing self-propelled movement of the first drive vehicle (<NUM>) and thereby the multi trolley vehicle (<NUM>) in at least one of the first and second directions corresponding to the at least one of the first and second directions of the trolley assembly (<NUM>), such that the multi trolley vehicle (<NUM>) is horizontally movable.