Patent Description:
<FIG> and <FIG> disclose a typical prior art automated storage and retrieval system <NUM> with a framework structure <NUM>. <FIG> and <FIG> disclose a prior art container handling vehicle <NUM>, <NUM> operating the system <NUM> disclosed in <FIG> and <FIG>, respectively.

The framework structure <NUM> comprises a plurality of upright members <NUM> and optionally a plurality of horizontal members <NUM> supporting the upright members <NUM>.

The framework structure <NUM> defines a storage grid <NUM> comprising storage columns <NUM> arranged in rows, in which storage columns <NUM> 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 storage grid <NUM> guards against horizontal movement of the storage containers <NUM> in the stacks <NUM>, and guides vertical movement of the storage containers <NUM>, but does normally not otherwise support the storage containers <NUM> when stacked.

The automated storage and retrieval system <NUM> comprises a container handling vehicle rail system <NUM> arranged in a grid pattern across the top of the storage <NUM>, on which rail system <NUM> a plurality of container handling vehicles <NUM>,<NUM> (as exemplified in <FIG> and <FIG>) 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 horizontal extent of one of the grid cells <NUM> constituting the grid pattern is in <FIG> and <FIG> marked by thick lines.

Each grid cell <NUM> has a width which is typically within the interval of <NUM> to <NUM>, and a length which is typically within the interval of <NUM> to <NUM>. Each grid opening <NUM> has a width and a length which is typically <NUM> to <NUM> less than the width and the length of the grid cell <NUM> due to the horizontal extent of the rails <NUM>,<NUM>.

In this way, the rail system <NUM> defines grid columns above which the container handling vehicles <NUM>,<NUM> can move laterally above the storage columns <NUM>, i.e. in a plane which is parallel to the horizontal X-Y plane.

Each prior art container handling vehicle <NUM>,<NUM> comprises a vehicle body and a wheel arrangement of eight wheels <NUM>,<NUM> where a first set of four wheels enable the lateral movement of the container handling vehicles <NUM>,<NUM> in the X direction and a second set of the remaining four wheels enable the lateral movement in the Y direction. One or both sets of wheels in the wheel arrangement can be lifted and lowered, so that the first set of wheels and/or the second set of wheels can be engaged with the respective set of rails <NUM>, <NUM> at any one time.

Each prior art container handling vehicle <NUM>,<NUM> also comprises a lifting device (not shown) 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 comprises one or more gripping / engaging devices (not shown) which are adapted to engage a storage container <NUM>, and which gripping / engaging devices can be lowered from the vehicle <NUM>,<NUM> so that the position of the gripping / engaging devices with respect to the vehicle <NUM>,<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 exemplary prior art grid <NUM> disclosed in <FIG> and <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> and <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 (not shown) for receiving and stowing a storage container <NUM> when transporting the storage container <NUM> across the rail system <NUM>. The storage space may comprise a cavity arranged centrally within the vehicle body, e.g. as is described in.

Alternatively, the container handling vehicles <NUM> may have a cantilever construction, as is described in NO317366.

The container handling vehicles <NUM> may have a footprint, i.e. an extent in the X and Y directions, which is generally equal to the lateral extent of a grid cell <NUM>, i.e. the extent of a grid cell <NUM> in the X and Y directions, e.g. as is described in <CIT>.

The term "lateral" used herein may mean "horizontal".

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

The rail system <NUM> may be a single rail (also denoted single track) system, as is shown in <FIG>. Alternatively, the rail system <NUM> may be a double rail (also denoted double track) system, as is shown in <FIG>, thus allowing a container handling vehicle <NUM> having a footprint generally corresponding to the lateral area defined by 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 neighboring that row. Both the single and double rail system, or a combination comprising a single and double rail arrangement in a single rail system <NUM>, forms a grid pattern in the horizontal plane P comprising a plurality of rectangular and uniform grid locations or grid cells <NUM>, where each grid cell <NUM> comprises a grid opening <NUM> being delimited by a pair of rails 110a, 110b of the first rails <NUM> and a pair of rails 111a, 111b of the second set of rails <NUM>. In <FIG> the grid cell <NUM> is indicated by a dashed box. For example, the sections of the rail-based system being made of aluminium are the rails, and on the upper surface of the rails, there are a pair of tracks that the wheels of the vehicle run in. However, the sections could be separate rails each with a track.

Consequently, rails 110a and 110b form pairs of neighboring rails defining parallel rows of grid cells running in the X direction, and rails 111a and 111b form pairs of neighboring rails defining parallel rows of grid cells running in the Y direction.

As shown in <FIG>, each grid cell <NUM> has a width Wc which is typically within the interval of <NUM> to <NUM>, and a length Lc which is typically within the interval of <NUM> to <NUM>. Each grid opening <NUM> has a width Wo and a length Lo which is typically <NUM> to <NUM> less than the width Wc and the length Lc of the grid cell <NUM>.

In the X and Y directions, neighboring grid cells <NUM> are arranged in contact with each other such that there is no space there-between.

In a storage grid <NUM>, a majority of the grid columns are storage columns <NUM>, i.e. grid columns <NUM> where storage containers <NUM> are stored in stacks <NUM>. However, a grid <NUM> normally has at least one grid column which is used not for storing storage containers <NUM>, but which comprises a location where the container handling vehicles <NUM>,<NUM> can drop off and/or pick up storage containers <NUM> so that they can be transported to a second location (not shown) where the storage containers <NUM> can be accessed from outside of the grid <NUM> or transferred out of or into the grid <NUM>. 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 "delivery column" <NUM>,<NUM>. The drop-off and pick-up ports of the container handling vehicles are referred to as the "upper ports of a delivery column" <NUM>,<NUM>. While the opposite end of the delivery column is referred to as the "lower ports of a delivery column".

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

The second location may typically be a picking or a stocking station where product items are removed from or positioned into the storage containers <NUM>. In a picking or a stocking station, the storage containers <NUM> are normally never removed from the automated storage and retrieval system <NUM>, but are returned into the storage grid <NUM> once accessed. For transfer of storage containers out or into the storage grid <NUM>, there are also lower ports provided in a delivery column, such lower ports are e.g. for transferring storage containers <NUM> to another storage facility (e.g. to another storage grid), directly to a transport vehicle (e.g. a train or a lorry), or to a production facility.

For monitoring and controlling the automated storage and retrieval system <NUM> (e.g. monitoring and controlling the location of respective storage containers <NUM> within the storage grid <NUM>; the content of each storage container <NUM>; and the movement of the container handling vehicles <NUM>,<NUM> so that a desired storage container <NUM> can be delivered to the desired location at the desired time without the container handling vehicles <NUM>,<NUM> colliding with each other), the automated storage and retrieval system <NUM> comprises a control system (not shown) which typically is computerized and which typically comprises a database for keeping track of the storage containers <NUM>.

A conveyor system comprising conveyors may be employed to transport the storage containers between the lower port of the delivery column <NUM>,<NUM> and the access station. If the lower port of the delivery column <NUM>,<NUM> and the access station are located at different levels, the conveyor system may comprise a lift device for transporting the storage containers <NUM> 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>.

Further, <CIT>, disclose an example of a prior art access system having conveyor belts (<FIG> in <CIT>) and a frame mounted rail (<FIG> in <CIT>) for transporting storage containers between delivery columns 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>,<NUM> is instructed to retrieve the target storage container <NUM> from its position in the grid <NUM> and to transport it to or through the delivery column <NUM>. This operation involves moving the container handling vehicle <NUM>,<NUM> to a grid location above the storage column <NUM> in which the target storage container <NUM> is positioned, retrieving the storage container <NUM> from the storage column <NUM> using the container handling vehicle's lifting device (not shown), and transporting the storage container <NUM> to the delivery column <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 <NUM>, the operation also involves temporarily moving the above-positioned storage containers prior to lifting the target storage container <NUM> from the storage column <NUM>. This step, which is sometimes referred to as "digging" within the art, may be performed with the same container handling vehicle <NUM>,<NUM> that is subsequently used for transporting the target storage container <NUM> to the delivery column, or with one or a plurality of other cooperating container handling vehicles <NUM>,<NUM>. Alternatively, or in addition, the automated storage and retrieval system <NUM> may have container handling vehicles <NUM>,<NUM> specifically dedicated to the task of temporarily removing storage containers <NUM> from a storage column <NUM>. However, the removed storage containers may alternatively be relocated to other storage columns <NUM>.

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

In situations where two rail systems are to be connected or constructed simultaneously for later connection, only minimal tolerances with respect to misalignment between the rail systems are possible. Significant misalignment can result in a vehicle becoming derailed.

Ambient temperatures or temperature differences within the building or area where the rail systems are arranged can also bring issues for the automated storage and retrieval system. The rails may expand and contract significantly, resulting in buckling or over tension in the rails, potentially giving rise to movement in the rails and ultimately risking that a container handling vehicle could derail. The problems of expansion and contraction will depend in part on the length of the rails. Thus, for rail systems of a significant length either in the X direction and/or in the Y direction, there is an increased risk of movement and with that buckling and/or excessive tension in the rail system.

<CIT> describes a rail system wherein the rail joints are bridged by a connecting element, the rail ends are aligned with one another and are displaceable in the rail direction. The rails and the connecting element are designed in such a way that there is no interruption in the running surfaces of the rail joint.

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 one or more of the aforementioned problem related to use of prior art storage and retrieval systems. Another objective is to provide a connection simplifying the connection of two rail systems.

Another objective is to provide a connection which solves, or at least mitigates, issues relating to expansion and/or contraction of rails, and in particular rails of significant length subject to large temperature differences with the risk of expansion and contraction as the result.

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

The invention relates to an expansion joint for connecting regions of a rail-based grid storage system, the expansion joint comprising:.

wherein the first or second rail element of the expansion joint comprises a pivot connection arrangement forming a link, the link being able to span a gap between the first and second rail elements, the pivot connection arrangement allowing the link to be pivoted between a non-connected position where the first and second rail elements of the expansion joint are not connected together and a connected position where the first and second rail elements of the expansion joint are connected together by the link and forms the junction area between the first or second rail element and the link.

The first rail element may comprise a protruding male part and the second rail element may comprise a receiving female part comprising a recess. Alternatively, the first rail element may comprise the recess and the second rail element may comprise the protruding male part.

The first and second rail elements of the expansion joint are arranged such that wheel(s) of the vehicles transfers weight from a first region to the second region via one of the first or second rail element to the other of the first or second rail element without experiencing a step in the track when passing the expansion joint.

In other words, the parts of the first and second rail elements that are arranged side-by-side each other in the transition form part of a continuous drive track(s) in the junction area where they overlap.

The junction area may define a dividing line between the first rail element and the second rail element that runs along a centre of the or each track where the first and second rail elements overlap, i.e. in the area where the first and second rail elements are arranged side-by-side/lateral relative each other.

When the first and second rail elements overlap (i.e. arranged side-by-side), the combined total width of the first and second rail elements are equal to the width of the each track.

The expansion joint may comprise a first and a second track, and the portions of the tracks may each form dividing lines running along a centre of the first and second track, respectively.

In an aspect, not part of the invention, the expansion joint may comprise a guide arrangement provided below the one or more tracks to support ends of the first and second rail elements and guide relative longitudinal movement thereof as the portions of the one or more tracks slide relative to each other in the junction area. The guide arrangement may comprise one or more of the following: an intermediate connection element, a slide connection, a roller-based connection, a link, a recess in second rail element, a recess in intermediate connection element or link.

If the guide arrangement comprises a roller-based connection, the roller-based connection may be arranged to prevent movement in a direction perpendicular to the longitudinal direction.

It is further described an automatic storage and retrieval system comprising first and second regions of a rail-based grid storage system and/or a delivery rail system, wherein the system comprises one or more expansion joints as described above and each of the first and second regions have rails with a profiled upper surface that define one or more tracks of the same gauge and profile as the one or more tracks in the expansion joint(s), the expansion joints being arranged as one or more connections between the first and second regions.

The first and second regions may be two regions of a rail-based grid storage system or two regions of a delivery rail system, i.e. the regions can be first and second rail systems of a rail-based grid storage system or the regions may be first and second rail systems of a delivery rail system.

The first and second regions of a rail-based grid storage system and/or a delivery rail system may comprise a grid arrangement of rails defining a plurality of grid cells.

The expansion joint can be arranged such that track(s) in the first set of rails overlap with track(s) in the expansion joint which again overlap with track(s) in the second set of rails, thereby forming a continuous track in the longitudinal direction, while at the same time allowing sliding movement of the first rail system relative the second rail system, and providing a smooth transition across the junction. For example, the expansion joint(s) are arranged so that there is no continuous slot extending laterally across the track that can pull apart - instead, the track is formed by two portions that overlap so that the wheel of the vehicle transfers weight from one to the other without experiencing a step in the track.

From a middle position of the expansion joint, it may preferably allow e.g. ±<NUM> movement in the longitudinal direction. However, the allowed movement in the longitudinal direction can be more or it can be less.

It is further described a method of connecting regions of a rail-based grid storage system and/or delivery rail system using one or more expansion joints as described above, each of the regions having rails with a profiled upper surface that defines one or more tracks of the same gauge and profile as the one or more tracks in the expansion joints, wherein the method comprises the steps of:.

The method may further comprise, before connecting the first and second regions, a step of:.

The first and second regions connected by the method may be regions of a rail-based storage grid system or a delivery rail system.

The expansion joint can be used in any rail-based systems, both grid storage systems and delivery rail systems.

The expansion joint can be used in a connection between two grid systems with rails in X direction or in Y direction.

It is also possible that the connection is between one grid system with rails in X and Y direction and one rail system comprising a single/double rail.

When connecting two regions of rail-based storage systems and/or delivery rail systems, the respective first rail part and second rail part to be connected can finish approximately midway across a cell. When connected, the cell where the expansion joint is arranged can be almost of a similar size as a standard cell, or it can be longer or it can be shorter. Vehicles can typically pass such cells in one direction, i.e. the direction of the expansion joint, because the distance between tracks for the wheels of the vehicles in the opposite direction may vary. The distance between the wheels are fixed. Furthermore, due to the varying distance between the tracks, the row where the expansion joint is arranged may not be used for storing storage containers.

The following drawings depict exemplary embodiments of the present invention and are appended to facilitate the understanding of the invention.

Furthermore, even if some of the features are described in relation to the expansion joint or system only, it is apparent that they are valid for the method of connecting rail-based storage systems as well, and vice versa. Hence, any features described in relation to the method, are also valid for the expansion joint and the system.

<FIG> is a side view of two storage grids <NUM>', <NUM>" which have been connected using an expansion joint <NUM>. The expansion joint <NUM> in <FIG> connects rails extending in the X direction of the two storage grids <NUM>', <NUM>". The storage grids <NUM>', <NUM>" may be of equal size or have a different size, both with regards to horizontal extent of the grids <NUM>', <NUM>" and vertical extent of the grids <NUM>', <NUM>". The disclosed storage grids <NUM>', <NUM>" both have the capacity of storing stacks <NUM> of four storage containers <NUM>. However, it is advantageous if the rails in the storage grids <NUM>', <NUM>" are flush with each other such that the container handling vehicles travelling between the storage grids <NUM>', <NUM>" can travel mainly within the same horizontal plane P independent of whether the container handling vehicle <NUM> is on storage grid with reference <NUM>', storage grid with reference <NUM>" or at the expansion joint <NUM> between the two storage grids <NUM>', <NUM>". , in other words, when two regions of the storage grids <NUM>', <NUM>" are connected, they function as one common large grid. Similarly, and as described in greater detail with reference to e.g. <FIG>, <FIG> and <FIG> when two regions of delivery rail system <NUM>, <NUM>', <NUM>" are connected, they function as one common large grid.

As indicated above, the two storage grids <NUM>', <NUM>" are, in <FIG>, connected in the X direction of the rails, where a first set of rails 20X in X direction on storage grid with reference <NUM>' is connected to a second set of rails 21X in the X direction of storage grid with reference <NUM>". A similar expansion joint <NUM> is arranged between all of the first set of rails 20X which have a corresponding second set of rails 21X along the same horizontal axis. In <FIG> there is a total of four expansion joints <NUM> connecting a total of four first set of rails 20X each with a dedicated second set of rails 21X. However, it is apparent that the number of expansion joints <NUM> and first and second sets of rails 20X, 21X may vary and that it can be more or it can be less.

Due to the change in the length of the expansion joint <NUM>, the space <NUM>, i.e. the row formed below the expansion joints <NUM>, will normally not serve as a storage space for containers <NUM>,<NUM>, and may instead be used as a passage or similar.

All rails extending in the X direction are identical, thus in all Figures reference to first set of rails 20X, 21X can be any of the individual rails (double rail/track system or single rail/track system) in the X direction.

Similarly, all rails extending in the Y direction are identical, thus in the Figures reference to first set of rails 20Y, 21Y can be any of the individual rails (double rail/track system or single rail/track system) in the Y direction.

<FIG> is a top side close up view of three of the expansion joints <NUM> between the first set of rails 20X in the X direction and the second set of rails 21X in the X direction of <FIG>. In <FIG>, the storage grids <NUM>', <NUM>", expansion joints <NUM> and container handling vehicle <NUM> are seen from the opposite side compared to <FIG>. The container handling vehicle <NUM> is disclosed carrying a storage container <NUM>.

<FIG> is a top view of the four expansion joints <NUM> connecting the first set of rails 20X and the second set of rails 21X in <FIG>.

<FIG> is a top side view of an expansion joint comprising a roller-based connection, the expansion joints <NUM> connecting first sets of rails 20Y in the Y direction of storage grid with reference <NUM>' and second sets of rails 21Y in the Y direction of storage grid with reference <NUM>". The expansion joints <NUM> connects the rail systems of the respective storage grids <NUM>', <NUM>". The expansion joint <NUM> comprising a roller-based connection is the same irrespective of used in connecting rails extending in the X direction or in the Y direction. Details of the expansion joints <NUM> with roller-based connection are given below with reference to <FIG>.

<FIG> is an alternative top side view of <FIG> showing more details of the expansion joint <NUM> comprising a roller-based connection.

<FIG> is a side view of a delivery rail system <NUM>, arranged below two storage grids <NUM>', <NUM>". The delivery rail system <NUM> originates from two delivery rails systems which have been connected using an expansion joint <NUM> according to an embodiment of the invention.

<FIG> is an enlarged view of section A in <FIG> showing a container handling vehicle <NUM> with wheel arrangement <NUM> on the delivery rail system <NUM>. Similar to the connection of the storage grids <NUM>', <NUM>" described in relation to <FIG>, the two delivery rail systems <NUM>', <NUM>" are, in <FIG>, connected in the X direction of the rails, where a first set of rails 20X in X direction on delivery rail system with reference <NUM>' is connected to a second set of rails 21X in the X direction of delivery rail system with reference <NUM>" via the expansion joint <NUM> comprising the first rail element <NUM> and the second rail element <NUM>. Identical expansion joints <NUM> are arranged between all of the first set of rails 20X which have a corresponding second set of rails 21X. In <FIG> there is a total of four expansion joints <NUM> connecting a total of four first sets of rails 20X, each with a dedicated second set of rails 21X. First and second rail elements <NUM>, <NUM> are connected at opposite sides of the expansion joints <NUM> between the expansion joint <NUM> and the respective regions to be connected (in the disclosed embodiment: first and second sets of rails 20X, 21X). This number this is by way of example only - it provides three lanes for the vehicles to travel along - two or more lanes will reduce problems if a vehicle breaks down (single point failure) due to the grid arrangement. At least three lanes may be preferred in terms of flexibility for routing while not occupying too much space. However, it could be more.

<FIG> is an enlarged view of the delivery rail system of <FIG>.

<FIG> is a top side view of the expansion joint of <FIG>.

<FIG> is an exploded view of the expansion joint <NUM> disclosed in <FIG> used in the connection between the first and second sets of rails 20X, 21X in the X direction. The expansion joint <NUM> comprises a first rail element <NUM>, in this embodiment a male protruding part connectable to the first set of rails 20X, and a second rail element <NUM>, in this embodiment a female receiving part, connectable to the second set of rails 20X. The first rail element <NUM> extends in an axial direction equal to the direction of the first set of rails 20X, and the second rail element <NUM> comprises a receiving part extending in an opposite axial direction relative the first rail element <NUM>. In <FIG> the expansion joint <NUM> further comprises an intermediate connection element <NUM>. The intermediate connection element <NUM> is shown as a slide connection and is adapted to be connected below the first rail element <NUM> using suitable fastening means such as screw, pin or bolt <NUM> through vertical hole(s) <NUM> in the intermediate connection element <NUM>. The second set of delivery rails <NUM>' is, below the second rail element <NUM>, provided with a recess for receiving the intermediate connection element <NUM> when the first and second sets of rails <NUM>',<NUM>" are connected. When connected, the first rail element <NUM> and the second rail element <NUM> at least partly overlap in a direction perpendicular to the axial direction and forms part of a rail system on which container handling vehicles <NUM>, <NUM> may travel. When connected, the first rail element <NUM>, i.e. the male part, is allowed to move in an axial direction relative the second rail element <NUM> in that the protruding part <NUM> of the first rail element is received in the recess <NUM> in the second rail element <NUM>, thereby forming a continuous drive track in the axial direction between the first set of delivery rails <NUM>' and the second set of delivery rails <NUM>". Furthermore, when connected, the axial flexibility of the expansion joint <NUM> allows for some relative movement between the rails in the first set of rails <NUM>' and the second set of rails <NUM>", e.g. +- <NUM>, +- <NUM>, or more or less. Non-continuous drive tracks are not acceptable for the container handling vehicles. Any non-continuous rails in the axial direction may lead to instable container handling vehicles and/or derailing.

<FIG> is an example of an expansion joint in the Y direction between regions in a rail-based storage system exemplified as a first set of delivery rails <NUM>' and a second set of delivery rails <NUM>". The expansion joint <NUM> comprises a slide connection.

<FIG> and <FIG> are exploded views of the expansion joint <NUM> in <FIG> in the Y direction of the first and second sets of delivery rails <NUM>', <NUM>", comprising a slide connection, where <FIG> is a side view and <FIG> is a top side view. The expansion joint <NUM> of <FIG> have almost all features in common with the expansion joint <NUM> described above in relation to <FIG> and will not be repeated, except for the intermediate connection element <NUM> which are provided with hole(s) <NUM> on its sidewalls instead of vertical holes. Consequently, the first set of rails <NUM>' also have corresponding hole(s) <NUM> for receiving fastening means (see <FIG>). This is due to the different construction of the rails running in the Y direction vs. the rails running in the X direction.

<FIG> is a close view of an expansion joint <NUM> comprising a slide connection in the Y direction of the rails and showing the Y direction wheels <NUM> of a container handling vehicle <NUM> about to pass the expansion joint <NUM>. As is clear from the Figure, the complementary shape of the recess <NUM> in the second rail element <NUM> and the protruding part of the first rail element <NUM> ensure a continuous drive track for the wheels of the container handling vehicle in that the protruding part and the recess <NUM> overlap in a direction perpendicular to the axial direction of the Y rails. In other words, the parts of the first and second rail elements <NUM>, <NUM> that are arranged side-by-side each other in the transition form part of a continuous drive track(s) in the junction area where they overlap.

<FIG> is an example an expansion joint <NUM> in the Y direction of the rails comprising a roller-based connection. <FIG> is a view from below of <FIG>. <FIG> is an exploded view of the expansion joint <NUM> of <FIG> comprising a roller-based connection, showing the components of one of the expansion joints <NUM> between a first rail system 20Y and a second rail system 21Y, in a Y direction. The expansion joint <NUM> comprises a first rail element <NUM>, in this embodiment a male part connectable to the first set of rails 20Y, and a second rail element <NUM>, in this embodiment a female part, connectable to the second set of rails 21Y. The first rail element <NUM> extends in an axial direction equal to the direction of the first set of rails 20Y, and the second rail element <NUM> comprises a receiving part extending in an opposite axial direction relative the first rail element <NUM>. The expansion joint <NUM> further comprises an intermediate connection element <NUM>. The intermediate connection element <NUM> is shown as a roller-based connection <NUM>. The roller-based connection <NUM> comprises two brackets <NUM>', <NUM>' connected on each side of the first set of rails 20Y and connected to each other using suitable fastening means such as screw and/or bolt <NUM>. In order to secure that the brackets <NUM>', <NUM>" are arranged in pre-defined distance from each other, a fixed distance element <NUM> can be arranged in between the two brackets <NUM>', <NUM>". Furthermore, as disclosed in <FIG>, two screws <NUM> are connected to the first set of rails 20Y. Each bracket <NUM>', <NUM>" is further provided with a recess <NUM> (only one recess shown in <FIG>). Rollers <NUM> (only one shown in <FIG>) are connected to the second set of rails 21Y and are provided to move inside respective recesses <NUM> in the horizontal plane, i.e. in the axial direction of the drive tracks. The recess <NUM> and roller <NUM> lock the first set of rails 20Y relative the second set of rails 21Y vertically (i.e. in the Z direction) and in the X direction, but allows translational relative movement between the first set of rails 20Y relative the second set of rails 21Y in the Y direction. When connected, the axial flexibility of the expansion joint <NUM> allows for some relative movement between the rails in the first set of rails 20Y and the second set of rails 21Y, e.g. +-<NUM>, +- <NUM>, or more or less. Furthermore, when connected, the first rail element <NUM>, i.e. the male part, is allowed to move in an axial direction relative the second rail element <NUM> in that the protruding part <NUM> of the first rail element is received in the recess <NUM> in the second rail element <NUM>, thereby forming a continuous drive track in the axial direction between the first set of rails 20Y and the second set of rails 21Y.

<FIG> is an example of an expansion joint <NUM> comprising a link <NUM>' connected to the second rail element <NUM> (and the second set of rails 21Y) via a pivot connection arrangement <NUM>. The pivot connection arrangement <NUM> is connected to the second set of rails 21Y and the link <NUM>' via suitable fastening means (e.g. pivoting bracket <NUM> fastened by screw, bolts, pins etc.) known to the skilled person.

In <FIG> it is shown that the pivot connection arrangement <NUM> and the link <NUM>' are pivoted in an upward direction relative the second set of rails 21Y. In <FIG> the first set of rails 20Y and the second set of rails 21Y are not connected, i.e. the expansion joint <NUM> is in a non-connected position. Alternatively, the pivot connection arrangement <NUM> can be pivoted to rest in a downward position and to be pivoted upwardly for connection with the first set of rails 20Y.

Although the pivot connection arrangement <NUM> is disclosed connected to the second rail element <NUM> (and thereby to the second set of rails 21Y), it is clear that the pivot connection arrangement <NUM> (and link <NUM>') can be connected to the first rail element <NUM> (and thereby to the first set of rails 20Y) instead.

As disclosed in <FIG>, the link <NUM>', which link <NUM>' can be considered to form part of the second rail element <NUM> in the solution disclosed in <FIG>, are formed with a receiving part, i.e. a recess <NUM>', on the end which is to be connected to the first rail element <NUM>. This recess <NUM>', i.e. female part, and complementary first rail element <NUM>, i.e. male protruding part, are formed in a similar manner as discussed above in relation to <FIG> and <FIG>. In addition, the end of the link <NUM>' closest to the second rail element <NUM> can be (as disclosed in <FIG>) formed with a similar recess <NUM>" to provide some flexibility in the connection between the link <NUM>' and the second rail element <NUM> (and thereby the second set of rails 21Y).

The cooperation between the link <NUM>' and the first set of rails 20Y may, when the link <NUM>' is arranged mainly horizontally connecting the first set of rails 20Y and the second set of rails 21Y, be such that parts of the link <NUM>' rests on a surface <NUM> on the first rail element <NUM>. The surface <NUM> is preferably substantially horizontal such that the expansion joint <NUM> provides substantially flush drive tracks between the first set of rails 20Y and the second set of rails 21Y for the container handling vehicles <NUM>, <NUM>, <NUM>.

<FIG> is an example of the expansion joint <NUM> in <FIG>, showing the expansion joint <NUM> in a connected position where the first and second set of rails 20Y, 21Y are connected.

<FIG> is a top-view of the expansion joint <NUM> of <FIG> in a connected position. In <FIG>, the recesses <NUM>', <NUM>" in the link <NUM>' and complementary parts of the first and second rail elements <NUM>, <NUM> are shown in more detail. The male part of the first rail element <NUM> extends approximately halfway into the recess <NUM>' of the link <NUM>' allowing some relative axial movement between the first set of rails 20Y and the second set of rails 21Y when connected.

The first rail element <NUM> can be the male part or the second rail element <NUM> can be the male part, and the first rail element <NUM> can be the female part or the second rail element <NUM> can be the female part. In this embodiment there are no separate intermediate element <NUM>, i.e. the expansion joint <NUM> is simply pivoted between connected position and non-connected position by pivoting the link <NUM>' between resting position (i.e. non-connected position) and active position (i.e. connected position).

The rail systems in <FIG> comprises a single track in the X direction and a double track in the Y direction, however this is only one of the options, as there may be either only single rails or only double rails both in the X and Y direction.

In the preceding description, various aspects of the expansion joint and the automated storage and retrieval system according to the invention have been described with reference to the illustrative embodiment. For purposes of explanation, specific numbers, systems and configurations were set forth in order to provide a thorough understanding of the system and its workings. However, this description is not intended to be construed in a limiting sense. For example, rails sensors in the container handling vehicles normally emit light towards the side which are reflected back by the sidewalls in the rails. When a container handling vehicle enters a XY cross, there are no sidewalls, thus the light is not reflected back to the sensor. However, if the expander joint has a part without side walls, false signals can be the result. Software in the vehicle can correct for any such false light to the rail/track sensor in the container handling vehicles when driving pass an expander joint, possibly in connection with measurement of cell size (the size of the cells with expander joints are not fixed as is the fixed grid cells). The overall control system, which control system keeps track of all vehicles in the system, knows when the vehicle is about to enter a cell with an expansion joint. When a vehicle enters a cell with an expansion joint, the overall control system may then either ignore the signal representing the false light at the expansion joint or, turn off the sensor in the vehicle when passing the expansion joint. Alternatively, the risk of such false lights may be reduced by arranging a slide sidewall at the expansion joint which moves together with the expansion joint or which is of such a size that it covers the expansion joint also in a maximum extended position.

<FIG> is an example of an expansion joint used in connection of single tracks. In the junction area of the expansion joint for single tracks, it is formed a S-shape, which can be seen in <FIG>. This is due to that both the first rail element <NUM> and the second rail element <NUM> are S-shaped. The divider line between the first rail element <NUM> and the second rail element <NUM> is preferably along the centre line of the track <NUM>'. If the rail is a single-track rail, then presumably the junction area would take the S -shape, but usually it will be a double-track rail and so these can be arranged as mirrored profiles to create the male part and the female part. The junction area as shown in <FIG>, with the S-shape from one track leading through to an S-shape across another which is arranged in a similar manner, so that the slots in the tracks <NUM>' are spread along the track <NUM>'. The gap in the middle between the first and second rail elements <NUM>, <NUM>, would not need to be as big as shown, corresponding to the size of the gap at the sides. If it is important for lateral stability to provide a male shape and a female shape, then the tracks on the opposite side of the grid cell could have mirrored profiles to provide that same interlocking effect.

Claim 1:
An expansion joint (<NUM>) for connecting regions of a rail-based grid storage system (<NUM>, <NUM>', <NUM>"; <NUM>, <NUM>', <NUM>"), the expansion joint (<NUM>) comprising:
- a first rail element (<NUM>) and a second rail element (<NUM>), the rail elements (<NUM>, <NUM>) being elongate and configured to slide relative to one another in a longitudinal direction in a junction area where they overlap,
- the expansion joint (<NUM>) having a profiled upper surface that defines one or more tracks (<NUM>', <NUM>") for supporting container handling vehicles (<NUM>, <NUM>, <NUM>), the one or more tracks (<NUM>', <NUM>") extending from the first rail element (<NUM>) through the junction area to the second rail element (<NUM>), wherein in the junction area, each rail element (<NUM>, <NUM>) provides a portion of the one or more tracks (<NUM>', <NUM>") of the profiled upper surface so that there is a transition extending along the expansion joint (<NUM>) from the first rail element (<NUM>) to the second rail element (<NUM>) for the one or more tracks (<NUM>', <NUM>"),
wherein the first or second rail element (<NUM>,<NUM>) of the expansion joint (<NUM>) comprises a pivot connection arrangement (<NUM>) forming a link (<NUM>'), the link (<NUM>') being able to span a gap between the first and second rail elements (<NUM>, <NUM>), the pivot connection arrangement (<NUM>) allowing the link (<NUM>') to be pivoted between a non-connected position where the first and second rail elements (<NUM>, <NUM>) of the expansion joint (<NUM>) are not connected together and a connected position where the first and second rail elements (<NUM>, <NUM>) of the expansion joint (<NUM>) are connected together by the link (<NUM>') and forms the junction area between the first or second rail element (<NUM>, <NUM>) and the link (<NUM>').