Container handling vehicle

Abstract

The present invention provides a container handling vehicle 501 for travelling on a rail system 108, the rail system comprising a first set of parallel rails 110 and a second set of parallel rails 111 arranged at right angles to the first set of rails 110, the container handling vehicle comprising a first set of wheels and a second set of wheels and a mechanism for vertically lifting the second set of wheels. In one embodiment, the container handling vehicle 501 comprises a rechargeable battery 30 arranged in the second section (S2).

Description

[Technical field]

[0001] The present invention relates to a container handling vehicle for travel in two perpendicular directions on a horizontal grid-based rail system. [Background technology]

[0002] FIG. 1 discloses a prior art automated storage and retrieval system 1 having a framework structure 100, and FIGS. 2, 3 and 4 disclose three different prior art container handling vehicles 201, 301, 401 suitable for operating on such a system 1.

[0003] The framework structure 100 comprises upright members 102 and a storage volume comprising storage columns 105 arranged in rows between the upright members 102. In these storage columns 105, storage containers 106, also known as bins, are stacked on top of each other to form stacks 107. The upright members 102 may typically be made of metal, for example extruded aluminum profiles.

[0004] The framework structure 100 of the automated storage and retrieval system 1 comprises a horizontal grid-based rail system 108 (i.e., rail grid) disposed across the top of the framework structure 100. A plurality of container handling vehicles 201, 301, 401 may also be operated on the rail system 108 to transport storage containers 106 up the storage columns 105 for raising the storage containers 106 from the storage columns 105 and lowering the storage containers 106 into the storage columns. The rail system 108 comprises a first set of parallel rails 110 disposed to guide movement of the container handling vehicles 201, 301, 401 in a second direction X across the top of the framework structure 100, and a second set of parallel rails 111 disposed at right angles to the first set of rails 110 to guide movement of the container handling vehicles 201, 301, 401 in a first direction Y perpendicular to the second direction X. The containers 106 stored in the columns 105 are accessed by the container handling vehicles 201, 301, 401 through access openings 112 in the rail system 108. The container handling vehicles 201, 301, 401 can move laterally above the storage columns 105, i.e. in a plane parallel to the horizontal XY plane.

[0005] The uprights 102 of the framework 100 may be used to guide the storage containers during their ascent from and descent into the column 105. The stacks 107 of containers 106 are typically freestanding.

[0006] Each prior art container handling vehicle 201, 301, 401 comprises a car body 201a, 301a, 401a, respectively, and first and second sets of wheels 201b, 201c, 301b, 301c, 401b, 401c that allow lateral movement of the container handling vehicle 201, 301, 401 in the X and Y directions. In Figures 2, 3 and 4 two wheels of each set are fully visible. The first set of wheels 201b, 301b, 401b are arranged to engage two adjacent rails of the first set of rails 110, and the second set of wheels 201c, 301c, 401c are arranged to engage two adjacent rails of the second set of rails 111. At least one of the sets of wheels 201b, 301b, 201c, 301c, 401b, 401c can be raised or lowered, thereby allowing the first set of wheels 201b, 301b, 401b and / or the second set of wheels 201c, 301c, 401c to be engaged or disengaged with their respective sets of rails 110, 111.

[0007] Each prior art container handling vehicle 201, 301, 401 also comprises a lifting device 404 (i.e., a container lifting device) (see FIG. 4) for vertical transportation of the storage containers 106 (e.g., for raising the storage containers 106 from the storage column 105 and lowering the storage containers 106 into the storage column). The lifting device 404 features a lifting frame 2 that comprises a container connector 3 and a guide pin 4 that is adapted to engage with the storage containers 106. The lifting frame 2 can be lowered from the vehicle 201, 301, 401, whereby the position of the lifting frame 2 relative to the vehicle 201, 301, 401 can be adjusted in a third direction Z perpendicular to the second direction X and the first direction Y. The lifting device of the container handling vehicle 201 is located in the vehicle body 201a in FIG. 2.

[0008] To raise and lower the lifting frame 2 (and optionally the connected storage containers 106), the lifting frame 2 is suspended from a band drive assembly by lifting bands 5. In the band drive assembly, the lifting bands are typically wound / unwound on at least one rotating lifting shaft or reel located on the container handling vehicle. Various designs of band drive assemblies are described, for example, in WO 2015 / 193278, WO 2017 / 129384 and WO 2019 / 206438.

[0009] Conventionally, and for purposes of this application, Z=1 identifies the top layer for storing storage containers below the rail system 108, i.e., the layer directly below the rail system 108, Z=2 identifies the second layer below the rail system 108, Z=3 identifies the third layer, and so on. In the exemplary prior art disclosed in FIG. 1, Z=8 identifies the bottom layer, the lowest layer of storage containers. Similarly, X=1···n and Y=1···n identify the location of each storage column 105 in the horizontal plane. Thus, by way of example, using the Cartesian coordinate system X, Y, Z shown in FIG. 1, the storage container identified as 106′ in FIG. 1 can be said to occupy storage location X=17, Y=1, Z=6. The container handling vehicles 201, 301, 401 can be said to travel in layer Z=0, and each storage column 105 can be identified by its X and Y coordinates. Thus, the storage containers shown in FIG. 1 extending above the rail system 108 are also said to be located at layer Z=0.

[0010] The storage volume of the framework structure 100 is often referred to as a grid 104, and the possible storage locations within this grid are referred to as storage cells. Each storage column may be identified by a location in the X and Y directions, while each storage cell may be identified by a container number in the X, Y and Z directions.

[0011] Each prior art container handling vehicle 201, 301, 401 includes a storage compartment or space for receiving and housing the storage containers 106 as they are transported across the rail system 108. The storage space may include a cavity disposed internally within the vehicle body 201a, as shown in Figures 2 and 4 and described, for example, in WO 2015 / 193278 and WO 2019 / 206487, the contents of which are incorporated herein by reference.

[0012] Figure 3 shows an alternative form of container handling vehicle 301 with a cantilever configuration. Such a vehicle is described in detail, for example, in Norwegian Patent No. 317366, the contents of which are also incorporated herein by reference.

[0013] 2 may have a footprint covering an area having dimensions in the X and Y directions approximately equal to the lateral extent of the storage column 105, for example, as described in WO 2015 / 193278, the contents of which are incorporated herein by reference. As used herein, the term "lateral" may mean "horizontal."

[0014] Alternatively, the cavity container handling vehicle 401 may have a footprint larger than the lateral area defined by the storage column 105 as shown in Figures 1 and 4, for example as disclosed in WO 2014 / 090684 or WO 2019 / 206487.

[0015] The lateral area defined by the storage columns is equal to the lateral area defined by a grid cell 122 of the rail system 108. The lateral area of ​​a grid cell includes the area of ​​the access opening 112 and half the width of the rails around the access opening.

[0016] The rail system 108 typically includes rails with grooves along which the vehicle wheels run. Alternatively, the rails may include upwardly projecting elements, and the vehicle wheels may include flanges to prevent derailment. These grooves and upwardly projecting elements are collectively known as tracks. Each rail may include one track, and each rail may include two parallel tracks, or the rail system may include one track rail in one direction and two track rails in the other direction. Each rail may include a pair of track members, and each track member may be provided with a single track, and the pair of track members may be fastened together to provide the rail in a given direction.

[0017] WO 2018 / 146304, the contents of which are incorporated herein by reference, shows an exemplary form of a rail system 108 comprising rails and parallel tracks in both the X and Y directions forming a rail grid.

[0018] In the framework 100, most columns 105 are storage columns 105, i.e. columns 105 where storage containers 106 are stored in stacks 107. However, some columns 105 may have other purposes. In FIG. 1, columns 119 and 120 are such dedicated columns used by container handling vehicles 201, 301, 401 to drop off and / or pick up storage containers 106 so that they can be transported to an access station (not shown), where they can be accessed from outside the framework 100 or transferred to the outside or inside of the framework 100. In the art, such locations are usually called "ports" and the columns where the ports are located can be called "port columns" 119, 120. The transport to the access station can be in any direction, i.e. horizontal, inclined and / or vertical. For example, storage containers 106 may be placed in random or dedicated columns 105 within the framework structure 100 and then picked up by any container handling vehicle and transported to port columns 119, 120 for further transport to an access station. Note that the term "inclined" refers to the transportation of storage containers 106 having a general transport direction somewhere between horizontal and vertical.

[0019] In FIG. 1 , the first port column 119 may, for example, be a dedicated drop-off port column at which container handling vehicles 201, 301, 401 can drop off storage containers 106 to be transported to an access station or transfer station, and the second port column 120 may be a dedicated pick-up port column at which container handling vehicles 201, 301, 401 can pick up storage containers 106 transported from an access station or transfer station.

[0020] An access station may typically be a picking or stocking station where product items are removed from or placed into a storage container 106. At a picking or stocking station, the storage container 106 is typically not removed from the automated storage and retrieval system 1 but is returned to the framework 100 again once accessed. A port may also be used to transfer a storage container to another storage facility (e.g., to another framework or to another automated storage and retrieval system), to a transport vehicle (e.g., a train or truck), or to a production facility.

[0021] A conveyor system comprising conveyors is typically used to transport the storage containers between the port columns 119, 120 and the access stations.

[0022] If the port columns 119, 120 and the access stations are located at different levels, the conveyor system may include a lifting device with a vertical component for vertically transporting the storage containers 106 between the port columns 119, 120 and the access stations.

[0023] A conveyor system may be arranged to transport the storage containers 106 between the different framework structures, for example as described in WO 2014 / 075937, the contents of which are incorporated herein by reference.

[0024] When a storage container 106 stored in one of the storage columns 105 disclosed in FIG. 1 is to be accessed, one of the container handling vehicles 201, 301, 401 is directed to retrieve the target storage container 106 from its location and transport it to the drop-off port column 119. This operation involves moving the container handling vehicle 201, 301, 401 to a position above the storage column 105 where the target storage container 106′ is located, using the lifting device 404 of the container handling vehicle 201, 301, 401 to retrieve the storage container 106 from the storage column 105, and transporting the storage container 106 to the drop-off port column 119. When the target storage container 106 is located deep within the stack 107, i.e., when one or more other storage containers 106 are positioned above the target storage container 106, the operation also involves temporarily moving the storage containers positioned above before lifting the target storage container 106 out of the storage column 105. This step, which may be referred to in the art as "digging," may be performed by the same container handling vehicle subsequently used to transport the target storage container to the drop-off port column 119, or by one or more other cooperating container handling vehicles. Alternatively or additionally, the automated storage and retrieval system 1 may have container handling vehicles 201, 301, 401 dedicated to the task of temporarily removing the storage container 106 from the storage column 105. Once the target storage container 106 has been removed from the storage column 105, the temporarily removed storage container 106 may be repositioned back to the original storage column 105. However, the removed storage container 106 may alternatively be relocated to another storage column 105.

[0025] When a storage container 106 is to be stored in one of the columns 105, one of the container handling vehicles 201, 301, 401 is directed to pick up the storage container 106 from the pickup port column 120 and transport the storage container 106 to a position above the storage column 105 where the storage container is to be stored. After any storage container 106 positioned at or above the target position in the stack 107 is removed, the container handling vehicle 201, 301, 401 positions the storage container 106 in the desired position. The removed storage container 106 may then be lowered and placed back into the storage column 105 or transferred to another storage column 105.

[0026] To monitor and control the automated storage and retrieval system 1, e.g., the position of each storage container 106 within the framework structure 100, the contents of each storage container 106, and the movements of the container handling vehicles 201, 301, 401 so that the container handling vehicles 201, 301, 401 can deliver the desired storage containers 106 to the desired locations at the desired times without colliding with each other, the automated storage and retrieval system 1 typically includes a control system 500 that is computerized and typically includes a database for maintaining the trajectory of the storage containers 106.

[0027] The prior art container handling vehicles 201, 401 shown in Figures 2 and 4 have several advantageous properties in view of the cantilevered vehicle 301. The properties include the guide / support given to the storage containers housed within the cavity, and the possibility of lifting highly loaded storage containers without increasing the weight of the vehicle to counterbalance the weight of the storage containers. Both properties entail that the vehicles may have increased acceleration / deceleration relative to the cantilevered vehicle 301. However, the potential increase in acceleration / deceleration is not fully realized due to the instability caused by both vehicles 201, 401 having substantially all drive and lifting components located above the cavity for housing the storage containers. [Prior art documents] [Patent documents]

[0028] [Patent Document 1] International Publication No. 2015 / 193278 [Patent Document 2] International Publication No. 2019 / 206487 Summary of the Invention [Means for solving the problem]

[0029] The invention is defined by the appended claims and the following.

[0030] In a first aspect, the present invention provides a container handling vehicle for travel on a rail system comprising a first set of parallel rails and a second set of parallel rails arranged at right angles to the first set of rails, the container handling vehicle comprising: a vehicle frame defining first and second sections of a container handling vehicle arranged side-by-side; a first set of wheels comprising a first pair of wheels and a second pair of wheels, the first and second pairs of wheels being located on opposite portions of the first section and, in use, enabling movement of the vehicle along a first direction on the rail system; a second set of wheels comprising a third pair of wheels and a fourth pair of wheels, the third pair of wheels and the fourth pair of wheels being positioned on opposite sides of the vehicle, each of the sides extending from one edge of the first section to one edge of the second section, the second set of wheels enabling, in use, movement of the vehicle along a second direction on the rail system, the second direction being perpendicular to the first direction, the second set of wheels being positioned such that they are movable in a direction perpendicular to the vehicle frame between an upper position in which the first set of wheels enable movement of the vehicle along the first direction and a lower position in which the second set of wheels enable movement of the vehicle along the second direction; Equipped with the third pair of wheels includes a first wheel and a second wheel, the fourth pair of wheels includes a third wheel and a fourth wheel; Each of the first and third wheels is attached to a corresponding first wheel link, each of the first wheel links including a first pivot coupling and a second pivot coupling, and each of the first wheel links is pivotally connected to the vehicle frame by the first pivot coupling; Each of the second and fourth wheels is attached to a corresponding second wheel link, each of the second wheel links including a third and fourth pivot coupling, and each of the second wheel links is pivotally connected to the vehicle frame by the third pivot coupling; a first wheel link supporting a first wheel and a second wheel link supporting a second wheel are connected by a first coupler link via respective second and fourth pivot couplings; A first wheel link supporting the third wheel and a second wheel link supporting the fourth wheel are connected through respective second and fourth pivot couplings by a second coupler link.

[0031] The rail system on which the container handling vehicles may travel is a horizontal grid-based rail system, which may also be referred to as a rail grid system.

[0032] In one embodiment of the container handling vehicle, the first wheel linkage may be located on the second section.

[0033] In one embodiment of the container handling vehicle, the second wheel linkage may be disposed in the first section.

[0034] In one embodiment of the container handling vehicle, the first and second coupler links may extend along opposite sides of the first section, i.e., extending to opposite sides of a cavity provided by the first section, such that a storage container may be positioned between the first and second coupler links when housed within the cavity.

[0035] In one embodiment of the container handling vehicle, the second section may include an actuator assembly configured to move the first wheel link about a respective first pivot coupling between a first angular position and a second angular position, the movement of the first wheel link being transmitted to the second wheel link via the first coupler link and the second coupler link such that the second set of wheels are in an upper position or a lower position when the first wheel link is in the first angular position and the second angular position.

[0036] In one embodiment of the container handling vehicle, the second section may include a cross member that fixes the angular positions of the first wheel links relative to one another such that the first wheel links move in unison about their respective first pivot couplings;

[0037] The actuator assembly may be operatively connected to at least one of the first wheel links and configured to move the first wheel link about its first pivot coupling between a first angular position and a second angular position.

[0038] The cross member may be connected to both of the first wheel links such that the positions of the first wheel links are fixed relative to one another.

[0039] The actuator assembly may be operatively connected between the vehicle frame and at least one of the first wheel links.

[0040] In one embodiment of the container handling vehicle, the actuator assembly may comprise a wheel lift motor or a linear actuator.

[0041] In one embodiment of the container handling vehicle, at least one of the first wheel links may include a fifth pivot coupling connected to the actuator assembly.

[0042] In one embodiment of the container handling vehicle, the actuator assembly includes an actuator link pivotally connected to at least one of the first wheel links. The actuator link may be connected to a fifth pivot coupling of the at least one first wheel link.

[0043] The actuator link may be part of a motion transmission assembly configured to convert or transmit rotational motion of the actuator assembly into a substantially linear motion acting on a fifth pivot coupling of one of the first wheel links.

[0044] In one embodiment, the container handling vehicle may include a drive shaft interconnecting the first wheel links, the drive shaft operably connected to drive the first wheel and the third wheel, preferably via respective drive bands.

[0045] The drive shaft may be connected to an electric motor. Rotational movement of the drive shaft may be transmitted to the first wheel and the third wheel.

[0046] The drive shaft and the cross member may be configured to move in parallel when the first wheel link is moved between the first angular position and the second angular position.

[0047] The drive shaft can be configured to move in unison with the first wheel links between the first and second angular positions. By moving in unison with the first wheel links and their respective supported wheels, both excessive wear on the drive band due to stretching and maintenance associated with tightening the drive band are minimized.

[0048] In one embodiment, the container handling vehicle may include a wheel drive assembly for the first and third wheels, the wheel drive assembly may include a drive shaft, a cross member, a wheel drive motor for driving the drive shaft, and a first wheel link. All parts of the wheel drive assembly may move / pivot in unison relative to the vehicle frame. The wheel drive assembly may pivot about a first pivot coupling of the first wheel link.

[0049] The drive shaft may be disposed in the second section.

[0050] In one embodiment, the container handling vehicle may include a first wheel drive motor for driving the drive shaft, the first wheel drive motor may be disposed in the second section.

[0051] The first wheel drive motor may be fixed to one of the first wheel links. The drive shaft may have a first end and a second end, and the drive shaft may extend through a centerline of the first wheel drive motor such that the first end is operably connected to the first wheel and the second end is operably connected to the third wheel. The first end may be operably connected to the first wheel by a first drive band and the second end may be operably connected to the third wheel by a second drive band.

[0052] In one embodiment, the container handling vehicle may include a second wheel drive motor for driving a second pair of wheels, the second wheel drive motor may be disposed in the second section, and the second pair of wheels may preferably be operably connected to the second wheel drive motor by a drive band.

[0053] In one embodiment of the container handling vehicle, the first coupler link and the second coupler link may be configured to move in a second direction toward the second wheel and the fourth wheel, respectively, when the first wheel link is moved from the second angular position to the first angular position. The first coupler link and the second coupler link may be configured such that the coupler links urge the second wheel links to pivot about their respective first pivot couplings when the coupler links are moved in the second direction.

[0054] In one embodiment of the container handling vehicle, the first section may include a lifting device for lifting the storage container and may provide a cavity in which the storage container may be housed. The second wheel and the fourth wheel may be positioned on opposite sides of the cavity such that the storage container may be positioned between the second wheel and the fourth wheel when housed within the cavity.

[0055] In one embodiment of the container handling vehicle, the lifting device may include at least one rotatable lifting shaft configured to raise and lower the lifting frame via a set of lifting bands, the lifting shaft being positioned in the first section above the cavity.

[0056] In one embodiment, the container handling vehicle may include a lift drive motor for driving the lift device, and the lift drive motor may be disposed in the second section.

[0057] In one embodiment of the container handling vehicle, the first coupler link and the second coupler link are configured to move in a second direction toward the first wheel and the third wheel, respectively, when the first wheel link is moved from the first angular position to the second angular position.

[0058] In one embodiment of the container handling vehicle, the first coupler link and the second coupler link are plate-like.

[0059] Each of the plate-like coupler links may include a wheel recess for a wheel connected to a respective first wheel link. Each of the plate-like coupler links may feature a first end pivotally connected to a second pivot coupling of a respective second wheel link and is pivotally connected to the second pivot coupling of the respective first wheel link at a portion of the coupler link disposed above the wheel recess.

[0060] The plate coupler link may act both as a force transmission element between the wheel link arms and as a body / cover that closes the lower part of the two sides of the container handling vehicle.

[0061] In one embodiment of the container handling vehicle, the first swivel coupling and the third swivel coupling may be located at a lower level than the second swivel coupling and the fourth swivel coupling.

[0062] In one embodiment, the container handling vehicle may include a rechargeable battery disposed in the second section.

[0063] In one embodiment, the container handling vehicle may be equipped with a set of electrodes for receiving power from a charging station, which may be disposed in the second section and connected to a rechargeable battery.

[0064] In one embodiment, the container handling vehicle may include a control unit located in the second section.

[0065] By locating the drive motor, battery and control unit all in the second section, cabling from the control unit to any of the controllable components is minimized, thus simplifying the construction of the container handling vehicle and making it more cost-effective.

[0066] In one embodiment of the container handling vehicle, the first pair of wheels, the second wheel, and the fourth wheel are non-driven wheels. Non-driven wheels may also be referred to as non-motorized wheels.

[0067] In one embodiment, the container handling vehicle may be equipped with a set of adjustable or replaceable distance pins that are configured to interact with a switch or sensor on the lift frame when the lift frame is in the upper position.

[0068] The adjustable or replaceable distance pins ensure that the efficiency of the container handling vehicle can be optimized with respect to the height of the storage container being lifted. The container handling vehicle can include four distance pins positioned to interact with the four corner sections of the lifting frame. The distance pins can be configured to stabilize the lifting frame, and any storage containers connected thereto, when the lifting frame is in the upper position.

[0069] In one embodiment of the container handling vehicle, each of the second wheel links may include a first edge section extending upward from the level of the third swivel coupling and a second edge section extending downward from the level of the third swivel coupling, the first edge section and the second edge section being oriented away from the connected first wheel link and tilted relative to each other and configured such that when moved around the third swivel coupling, the second wheel link does not extend beyond the outside of the first pair of wheels.

[0070] In one embodiment of the container handling vehicle, the first wheel and the third wheel are disposed in the second section.

[0071] In one embodiment of the container handling vehicle, the first section and the second section are positioned side-by-side such that a centre point of the footprint of the first section is eccentrically positioned relative to a centre point of the footprint of the container handling vehicle.

[0072] In one embodiment of the container handling vehicle, the second and fourth wheels may have a smaller diameter than the first and third wheels. The difference in wheel diameter allows the motorized wheels, i.e., the first and third wheels, to have a relatively large diameter that provides optimal wheel contact with the rail system, while the non-driven wheels, i.e., the second and fourth wheels, may be positioned further away from the second section to allow more weight to be supported by the motorized wheels.

[0073] In a second aspect, the present invention provides a storage system comprising a container handling vehicle as defined in any one of the preceding claims, the storage system comprising a framework structure having a plurality of storage columns for accommodating vertical stacks of storage containers, and a rail system along which the vehicle can move in two perpendicular directions above the storage columns.

[0074] In one embodiment, the storage system comprises a plurality of uprights, with each storage column defined by four uprights.

[0075] In one embodiment, the storage system comprises a rail system disposed on an upright member, the rail system comprising a first set of parallel rails and a second set of parallel rails disposed perpendicular to the first set of rails, the first and second sets of rails providing a horizontal grid-based rail system that defines a plurality of grid cells.

[0076] In one embodiment of the storage system, the footprint of the first section may be on the order of the size of a grid cell of the rail system, and the second section may have a footprint less than half the area of ​​a grid cell.

[0077] A grid cell may be defined as the cross-sectional area between the vertical center plane of opposing rails extending in the X direction and the vertical center plane of opposing rails extending in the Y direction.

[0078] A grid cell opening may be defined as the open cross-sectional area between two opposing rails extending in the X direction and two opposing rails extending in the Y direction.

[0079] In one embodiment of the storage system, the footprint of the second section is less than half the size of the footprint of the first section (a size ratio of less than 1:2 relative to the first section). When the container handling vehicle is positioned above a grid cell in a position where it can raise and lower storage containers into and out of the first section, the second section extends into adjacent grid cells. However, the total footprint of the container handling vehicle is less than 1.5 grid cells in the second direction and at most one grid cell wide in the first direction. In other words, the lateral extent of the container handling vehicle in the first direction corresponds to the lateral extent of the track in one cell and at most 1.5 grid cells in the second direction perpendicular to the first direction. As a result, in a typical storage system in which two of the aforementioned container handling vehicles are operated and directed in opposite directions, the container handling vehicles may travel along adjacent rows of grid cells occupying three grid cells when passing each other in a first direction, while occupying two grid cells when passing each other in a second direction.

[0080] In a third aspect, the present invention provides a method of assembling a container handling vehicle according to any embodiment of the first aspect, the method comprising: a) assembling a second section of a vehicle frame, the second section including a second pair of wheels, a first wheel link, a first wheel, and a third wheel; b) connecting a first section of a vehicle frame to a second section, the first section including a first pair of wheels, a second wheel link, a second wheel, and a fourth wheel; c) interconnecting the first wheel links to respective second wheel links by first coupler links and second coupler links; Includes.

[0081] In one embodiment of the method according to the third aspect, the second section assembled in step a may comprise any or all of the first wheel drive motor, the second wheel drive motor, the lift drive motor, the actuator assembly, the drive shaft, the cross member, and the control unit.

[0082] In a fourth aspect, the present invention provides a method of changing the direction of travel of a container handling vehicle according to any embodiment of the first aspect, comprising: first wheel links interconnected by a drive shaft and a cross member, the drive shaft operatively connected to drive the first wheel and the third wheel, the cross member arranged to fix the angular positions of the first wheel links relative to each other such that the first wheel links move in unison about their respective first pivot couplings; The method is: - rotating the first wheel link, the drive shaft, and the cross member in unison about an axis extending between the first pivot coupling; Thereby, the first wheel link is moved from a first angular position to a second angular position, and the second set of wheels is moved from an upper position in which the container handling vehicle may move in a first direction to a lower position in which the container handling vehicle may move in a second direction.

[0083] In one embodiment of the method according to the fourth aspect, the drive shaft is operably connected to the first wheel by a first drive band and to the third wheel by a second drive band, the length of the drive bands being constant during coincident rotation of the first wheel link, the drive shaft, and the cross member about an axis extending between the first pivot coupling. [Brief description of the drawings]

[0084] Embodiments of the invention will now be described in detail, by way of example only, with reference to the following drawings, in which:

[0085] [Figure 1] FIG. 1 is a perspective view of a framework structure of a prior art automated storage and retrieval system.

[0086] [Diagram 2] FIG. 1 is a perspective view of a prior art container handling vehicle having a centrally located cavity for carrying a storage container therein.

[0087] [Diagram 3] FIG. 1 is a perspective view of a prior art container handling vehicle having a cantilevered section for carrying storage containers downward.

[0088] [Figure 4] FIG. 1 is a perspective view of a prior art container handling vehicle showing a container lifting assembly.

[0089] [Diagram 5] FIG. 5 is a perspective view of the container handling vehicle of FIG. 4 without the side panels.

[0090] [Figure 6] FIG. 1 is an exploded view of a first exemplary embodiment of a container handling vehicle according to the present invention; [Figure 7] FIG. 1 is an exploded view of a first exemplary embodiment of a container handling vehicle according to the present invention;

[0091] [Figure 8] FIG. 1 is a perspective view of a wheel lift assembly according to the present invention;

[0092] [Figure 9] FIG. 8 is a perspective side view of the container handling vehicle of FIGS. 6 and 7. [Figure 10] FIG. 8 is a perspective side view of the container handling vehicle of FIGS. 6 and 7.

[0093] [Figure 11] FIG. 2 is a perspective view of a second exemplary embodiment of a container handling vehicle according to the present invention; [Figure 12] FIG. 2 is a perspective view of a second exemplary embodiment of a container handling vehicle according to the present invention; [Figure 13] FIG. 2 is a perspective view of a second exemplary embodiment of a container handling vehicle according to the present invention; [Figure 14] FIG. 2 is a perspective view of a second exemplary embodiment of a container handling vehicle according to the present invention; [Figure 15] FIG. 2 is a perspective view of a second exemplary embodiment of a container handling vehicle according to the present invention; [Figure 16] FIG. 2 is a perspective view of a second exemplary embodiment of a container handling vehicle according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0094] Embodiments of the invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which:

[0095] As explained in the Background section, prior art container handling vehicles (see Figures 2, 4 and 5) that are equipped with cavities for accommodating storage containers have certain advantageous features. In particular, the guide / support provided to the storage containers when accommodated in the cavities entails that the vehicles may have increased acceleration / delay relative to the cantilevered container handling vehicle 301 shown in Figure 3. However, the potential increase in acceleration / delay is not fully realized due to vehicle instability. The instability is caused by both vehicles 201, 401 having most of the drive, power, control and lifting components located above the cavity (providing a high center of gravity).

[0096] The container handling vehicle body of Fig. 4 and Fig. 5 comprises a first section S1 and a second section S2 arranged side by side. An arrangement with a first section S1 and a second section S2 is disclosed in PCT / EP2018 / 077732. Due to the increased footprint compared to the footprint of the vehicle of Fig. 2, the stability is slightly improved. However, as shown in Fig. 5, the prior art container handling vehicle 401 features a wheel lifting component including at least a control unit 19, a replaceable battery 18, and a wheel lifting shaft 20 arranged above the cavity 26. The wheel lifting shaft 20 extends above the cavity interconnecting two opposing wheel lifting plates 21a, 21b. It is noted that the wheel drive motor of the container handling vehicle 401 is not arranged above the cavity. The positioning of the wheel motor is made possible by using a wheel hub motor 38. The advantage of using wheel hub motors is that all wheels of the container handling vehicle can be drive wheels providing enhanced wheel traction. The disadvantage of using multiple wheel hub motors is the relatively high cost and potentially increased service / maintenance. In addition, the power and torque that can be provided by the wheel hub motors is limited because the wheel hub motors must have a size that allows them to fit within the vehicle without extending into the cavity of the first section or interfering with each other in the second section.

[0097] The present invention provides a container handling vehicle having improved stability and drive wheel traction. Further advantages of the container handling vehicle described below include lower service costs and improved manufacturability of the vehicle.

[0098] A first exemplary embodiment of a container handling vehicle 501 according to the present invention is shown in FIGS.

[0099] The container handling vehicle is suitable for use in a prior art storage system, as described in the Background section and shown in FIG.

[0100] The container handling vehicle 501 features a vehicle frame 6 which defines a first section S1 and a second section S2 of the container handling vehicle 501 arranged side by side, similar to the vehicle frame of the prior art vehicle 401 described above.

[0101] The first section S1 comprises a lifting device for lifting the storage container 106 and provides a cavity 26 in which the storage container 106 can be accommodated. The lifting device has a lifting frame 2 and two rotatable lifting shafts 33 configured to raise and lower the lifting frame 2 via a pair of lifting bands 5. A lifting drive motor 28 for driving the lifting device, i.e. for rotating the lifting shafts, is disposed in the second section S2.

[0102] The container handling vehicle has a first set of wheels and a second set of wheels configured to move the vehicle on a rail system 108. The rail system includes a first set of parallel rails 110 and a second set of parallel rails 111 arranged at a right angle to the first set of rails 110. The rail system is arranged in a horizontal grid-based manner.

[0103] The first set of wheels comprises a first pair of wheels 7a, 7b and a second pair of wheels 7c, 7d, which are arranged on opposite parts of the first section S1 and enable movement of the vehicle 501 along a first direction Y on the rail system 108.

[0104] The second set of wheels comprises a third pair of wheels 8a, 8b and a fourth pair of wheels 8c, 8d. The third and fourth pairs of wheels are arranged on opposite sides of the vehicle, each side extending from one edge of the first section S1 to one edge of the second section S2, and the second set of wheels allows the vehicle 501 to move along a second direction X on the rail system 108. The second direction X is perpendicular to the first direction Y. The third pair of wheels comprises the first wheel 8a and the second wheel 8b, and the fourth pair of wheels comprises the third wheel 8c and the fourth wheel 8d. The second wheel 8b and the fourth wheel 8d are arranged on the first section S1 and are located on opposite sides of the cavity 26.

[0105] To allow for a change in the direction in which the vehicle travels on the rail system, the second set of wheels is arranged to be movable in a direction Z perpendicular to the vehicle frame 6. The second set of wheels may be moved between an upper position, in which the first set of wheels allow for movement of the vehicle 501 along a first direction Y, and a lower position, in which the second set of wheels allow for movement of the vehicle 501 along a second direction X.

[0106] Vertical movement of the second set of wheels is obtained by a wheel lift mechanism featuring pivotable wheel links 9, 12 connected by coupler links 15a, 15b and driven by actuator assemblies 17, 23.

[0107] In the wheel lifting mechanism, each of the first wheel 8a and the third wheel 8c is attached to a corresponding first wheel link 9, which includes a first pivot coupling 10 and a second pivot coupling 11. The first wheel links 9 are pivotally connected to the vehicle frame 6 by their respective first pivot couplings 10.

[0108] Similarly, the second wheel 8b and the fourth wheel 8d are each attached to a corresponding second wheel link 12, which in turn includes a third pivot coupling 13 and a fourth pivot coupling 14. The second wheel links 12 are pivotally connected to the vehicle frame 6 by their respective third pivot couplings 13.

[0109] A first wheel link 9 supporting a first wheel 8a and a second wheel link 12 supporting a second wheel 8b are connected by a first coupler link 15a through respective second and fourth pivot couplings 11, 14. A first wheel link 9 supporting a third wheel 8c and a second wheel link 12 supporting a fourth wheel 8d are connected by a second coupler link 15b through respective second and fourth pivot couplings 11, 14. The first coupler link 15a and the second coupler link 15b extend along opposite sides of the cavity 26 in the first section S1.

[0110] The first coupler link 15a and the second coupler link 15b are plate-like and function both as force or motion transmission elements between the first wheel link 9 and the second wheel link 12, and as bodywork closing the two lower sides of the vehicle. This dual function of the coupler links 15a, 15b provides a cost-effective, lightweight and simple mechanical solution.

[0111] The second section S2 includes a cross member 16 connected to both first wheel links 9. The cross member is configured to fix the angular positions of the first wheel links 9 relative to each other such that the first wheel links 9 move in unison about their respective first pivot couplings 10.

[0112] The actuator assembly is disposed in the second section S2 and features a wheel lift motor 17 and an actuator link 23. The actuator link is connected to one of the first wheel links 9 by a fifth pivot coupling 27. The actuator assembly is configured to move the first wheel link 9 between a first angular position and a second angular position about the respective first pivot coupling 10. The movement of the first wheel link 9 is transmitted to the second wheel link 12 via the first coupler link 15a and the second coupler link 15b, whereby the second set of wheels is in an upper position (see FIG. 10) or a lower position (see FIG. 9) when the first wheel link 9 is in the first angular position and the second angular position, respectively.

[0113] The first coupler link 15a and the second coupler link 15b are configured to move in the second direction X toward the second wheel 8b and the fourth wheel 8d, respectively, when the first wheel link 9 is moved from the second angular position to the first angular position, and are configured to move in the second direction X toward the first wheel 8a and the third wheel 8c, respectively, when the first wheel link 9 is moved from the first angular position to the second angular position.

[0114] Each of the second wheel links 12 comprises a first edge section 37a extending upwards from the level of the third pivot coupling 13 and a second edge section 37b extending downwards from the level of the third pivot coupling 13. The first edge section 37a and the second edge section 37b face away from the connected first wheel link 9 and are inclined relative to each other so as not to extend beyond the outside of the first pair of wheels 7a, 7b when the second wheel link 12 is moved around the third pivot coupling 13.

[0115] The container handling vehicle 501 features four driven or motorized wheels: a first wheel 8a, a third wheel 8c, and a second pair of wheels 7c, 7d. The remaining wheels in the exemplary embodiment are non-driven wheels.

[0116] The second wheel 8b and the fourth wheel 8d have a diameter D1 smaller than the diameter D2 of the first wheel 8a and the third wheel 8c (see FIG. 10). The smaller diameter allows the second wheel 8b and the fourth wheel 8d, i.e. the rotation axis of the second wheel 8b and the fourth wheel 8d, to be positioned further away from the second section S2 without increasing the footprint of the container handling vehicle by extending beyond the outside of the first pair of wheels 7a, 7b. The increased distance to the second section S2 ensures that the first wheel 8a and the third wheel 8c, i.e. two of the motorized wheels, support more weight and therefore have optimal traction. The larger diameter of the motorized wheels provides optimal contact and traction with the rail system 108 on which the container handling vehicle 501 can operate.

[0117] A drive shaft 24 interconnecting the first wheel links 9 is disposed in the second section S2. The drive shaft 24 is driven by a first electric motor 25 (i.e., a first wheel drive motor) and is operatively connected to drive the first wheel 8a and the third wheel 8c via respective drive bands 36.

[0118] A second electric motor 29 (i.e., a second wheel drive motor) for driving the second pair of wheels 7c, 7d is disposed in the second section S2. The second pair of wheels 7c, 7d are operably connected to the second electric motor 29 by a drive band 35.

[0119] The drive shaft 24 and cross member 16 are configured to move in parallel as the first wheel link 9 is moved between the first and second angular positions. The drive shaft 24 and cross member 16 are configured to move in unison with the first wheel link 9 between the first and second angular positions. By moving the drive shaft in unison with the first wheel link 9, both excessive wear on the drive band 36 due to stretching and maintenance associated with tightening the drive band 36 are minimized.

[0120] In a further embodiment, the remaining wheels, i.e. the second wheel 8b, the fourth wheel 8d, and the first pair of wheels 7a, 7b, may be driven by wheel hub motors. However, the addition of additional wheel drive motors is expensive and is not believed to provide significant speed and / or acceleration related advantages. As a result, using a combination of driven and non-driven wheels may provide a cost-effective solution with minimal performance differential. Weight is also reduced by avoiding additional driven wheels.

[0121] Substantially all drive, power, and control components of the container handling vehicle 501 are located in the second section S2. The weight of these components is primarily supported by the drive wheels in or at the second section S2 so that the drive wheels have excellent traction enabling high acceleration of the vehicle.

[0122] Power for driving the motor of the container handling vehicle is provided by a rechargeable battery 30 arranged in the second section S2. The rechargeable battery 30 is connected to a pair of electrodes 31. The electrodes 31 are configured to receive power from a charging station. The two electrodes 31 are arranged on opposite sides of a vertical centre plane of the container handling vehicle, the vertical centre plane extending in a second direction X. An advantageous effect of having such separated electrodes 31 is that a lateral skew of the container handling vehicle relative to the second direction X during initial connection to the charging station is minimized. A suitable charging station is disclosed for example in PCT / EP2021 / 074340.

[0123] A control unit 19, which controls at least the drive components (i.e. the first and second electric motors 25, 29, the wheel lift motor 17, and the lift drive motor 28) is located in the second section (S2). By locating all drive components and the battery in the second section S2, the cabling from the control unit 19 to any of the controllable components is minimized.

[0124] A set of interchangeable distance pins 22 are positioned above the lift frame 2. The distance pins 22 are configured to interact with switches 32 on the top of the lift frame 2 when the lift frame 2 is in the upper position.

[0125] A second exemplary container handling vehicle 501' is shown in Figures 11 to 16. The container handling vehicle 501' is the same as the vehicle in Figures 6 to 10 except for the length of the distance pin 22'.

[0126] The distance pins 22, 22' ensure that the efficiency of the container handling vehicle 501, 501' can be optimized with respect to the height of the storage container 106 being lifted. If the container handling vehicle 501 is to be used for taller storage containers, a shorter distance pin 22' can be installed to ensure that the container is not lifted higher than required to enter the cavity 26.

[0127] In an alternative embodiment, the distance pins 22, 22' may not be replaceable but may be adjustable, i.e. have an adjustable height. An adjustable distance pin may be obtained, for example, by having a telescoping or collapsible distance pin.

[0128] Each of the container handling vehicles 501, 501' includes four distance pins 22, 22' positioned to interact with the lift frame at its four corners. The distance pins 22, 22' may also be configured to stabilize the lift frame 2, and any storage containers 106 connected thereto, when the lift frame 2 is in the upper position.

[0129] The configuration of the container handling vehicle 501 of the present invention allows for a very efficient method of assembly since the second section S2 and most of the components that make up the vehicle may constitute a pre-assembled vehicle module. The vehicle module may comprise the second section S2 of the vehicle frame 6 including the second pair of wheels 7c, 7d, the first wheel link 9, the first wheel 8a, the third wheel 8c, the first wheel drive motor 25, the second wheel drive motor 29, the lift drive motor 28, the actuator assemblies 17, 23, the drive shaft 24, the cross member 16, and the control unit 19.

[0130] When a complete container handling vehicle is to be assembled, a first section S1 of the vehicle frame 6 may be connected to the vehicle module, the first section comprising a first pair of wheels 7a, 7b, a second wheel link 12, a second wheel 8b and a fourth wheel 8d, and finally interconnecting the first wheel link 9 to the respective second wheel link 12 by means of a first coupler link 15a and a second coupler link 15b. (List of reference numbers) 1. Prior Art Automatic Storage and Retrieval System 2 Lifting frame 3 Container Connector 4 Guide pins 5. Lifting Band 6 Vehicle Frame 7a, 7b First pair of wheels 7c, 7d Second pair of wheels 8a, 8b Third pair of wheels, first wheel, second wheel 8c, 8d Fourth pair of wheels, third wheel, fourth wheel 9 First Wheel Link 10 First swivel coupling 11 Second swivel coupling 12 Second wheel link 13 Third swivel coupling 14 Fourth swivel coupling 15a First Coupler Link 15b Second Coupler Link 16 Cross member 17 Wheel lift motor 18 Replaceable Battery 19 Control Unit 20 Wheel lift shaft 21a, 21b Wheel lift plate 22 Distance Pin 23 Actuator Link 24 Drive shaft 25 First wheel drive motor 26 Cavity 27 Fifth swivel coupling 28 Lift drive motor 29 Second wheel drive motor 30 Rechargeable Batteries 31 electrode 32 Switches / Sensors 33 Lifting shaft 35 Drive Band 36 Drive Band 37a first edge section 37b Second edge section 38 Wheel hub motor 100 Frame structure 102 Upright members of frame structures 103 Horizontal members of frame structures 105 Storage Column 106 Storage Container 106' Specific location of storage container 107 Stack 108 Rail System 110 Parallel rail in the second direction (X) 110a: first rail in second direction (X) 110b second rail in second direction (X) 111 Parallel rail in the first direction (Y) 111a First rail in first direction (Y) 111b Second rail in first direction (Y) 112 Access opening 119 First Port Column 120 Second Port Column 122 grid cells 201 Prior Art Container Handling Vehicles 201a Body of container handling vehicle 201 201b Drive means / wheel arrangement, second direction (X) 201c Drive means / wheel arrangement, first direction (Y) 301 Prior art cantilever container handling vehicle 301a Body of container handling vehicle 301 301b Driving means in the second direction (X) 301c Driving means in the first direction (Y) 401 Prior art container handling vehicles 401a Body of container handling vehicle 401 401b Driving means in the second direction (X) 401c Driving means in the first direction (Y) D1,D2 Wheel diameter S1 First Section S2 Second Section X Second Direction Y Primary Direction Z third direction

Claims

1. A container handling vehicle (501) for travelling on a rail system (108), said rail system (108) comprising a first set of parallel rails (110) and a second set of parallel rails (111) arranged at right angles to said first set of rails (110), said container handling vehicle (501) comprising: a vehicle frame (6) defining a first section (S1) and a second section (S2) of the container handling vehicle (501) arranged side by side; a first set of wheels comprising a first pair of wheels (7a, 7b) and a second pair of wheels (7c, 7d), the first and second pairs of wheels being arranged on opposite parts of the first section (S1) and enabling, in use, movement of the container handling vehicle (501) along a first direction (Y) on the rail system (108); a second set of wheels comprising a third pair of wheels (8a, 8b) and a fourth pair of wheels (8c, 8d); Equipped with the third pair of wheels and the fourth pair of wheels are arranged on opposite sides of the container handling vehicle (501), each of said sides extending from one edge of the first section (S1) to one edge of the second section (S2); the second set of wheels, in use, enables movement of the container handling vehicle (501) along a second direction (X) on the rail system (108), the second direction (X) being perpendicular to the first direction (Y); the second set of wheels are arranged to be movable in a direction (Z) perpendicular to the vehicle frame (6) between an upper position in which the first set of wheels enables movement of the container handling vehicle (501) along the first direction (Y) and a lower position in which the second set of wheels enables movement of the container handling vehicle (501) along the second direction (X); the third pair of wheels (8a, 8b) comprises a first wheel (8a) and a second wheel (8b), and the fourth pair of wheels (8c, 8d) comprises a third wheel (8c) and a fourth wheel (8d); each of the first wheels (8 a) and the third wheels (8 c) is attached to a corresponding first wheel link (9), each first wheel link (9) comprising a first swivel coupling (10) and a second swivel coupling (11) and is rotatably connected to the vehicle frame (6) by the first swivel coupling (10); the container handling vehicle (501) further comprises a drive shaft (24) interconnecting the first wheel links (9), the drive shaft (24) being operatively connected to drive the first wheels (8 a) and the third wheels (8 c); Each of the second wheel (8b) and the fourth wheel (8d) is attached to a corresponding second wheel link (12), and each second wheel link (12) includes a third pivot coupling (13) and a fourth pivot coupling (14), and is pivotally connected to the vehicle frame (6) by the third pivot coupling (13); the first wheel link (9) supporting the first wheel (8a) and the second wheel link (12) supporting the second wheel (8b) are connected via the second and fourth pivot couplings (11, 14) by a first coupler link (15a); The first wheel link (9) supporting the third wheel (8c) and the second wheel link (12) supporting the fourth wheel (8d) are connected via the second and fourth swivel couplings (11, 14) by a second coupler link (15b).

2. the second section (S2) comprises an actuator assembly (17, 23) arranged to move the first wheel link (9) between a first angular position and a second angular position about the respective first pivot coupling (10), the movement of the first wheel link (9) being transmitted to the second wheel link (12) via the first coupler link (15a) and the second coupler link (15b); 2. A container handling vehicle (501) as described in claim 1, whereby the second set of wheels is in the upper position or the lower position when the first wheel link (9) is in the first angular position and the second angular position, respectively.

3. the second section (S2) comprises a cross member (16) that fixes the angular positions of the first wheel links (9) relative to one another, so that the first wheel links (9) move in unison about their respective first pivot couplings (10); 3. The container handling vehicle (501) of claim 2, wherein the actuator assembly (17, 23) is operably connected to at least one of the first wheel links (9) and is arranged to move the first wheel link (9) about its first pivot coupling (10) between the first angular position and the second angular position.

4. 3. The container handling vehicle (501) of claim 2, wherein the actuator assembly (17, 23) comprises a wheel lift motor (17) or a linear actuator.

5. 3. The container handling vehicle (501) of claim 2, wherein at least one of the first wheel links (9) comprises a fifth pivot coupling (27) connected to the actuator assembly (17, 23).

6. 3. The container handling vehicle (501) of claim 2, wherein the actuator assembly (17, 23) comprises an actuator link (23) pivotally connected to one of the first wheel links (9).

7. A container handling vehicle (501) as described in claim 1, wherein the drive shaft (24) is operably connected to drive the first wheel (8a) and the third wheel (8c) via respective drive bands (36).

8. 8. The container handling vehicle (501) according to claim 7, further comprising a first wheel drive motor (25) for driving the drive shaft (24), the first wheel drive motor (25) being arranged in the second section (S2).

9. 2. The container handling vehicle (501) of claim 1, further comprising a second wheel drive motor (29) for driving the second pair of wheels (7c, 7d), the second wheel drive motor (29) being arranged in the second section (S2), and the second pair of wheels (7c, 7d) being operably connected to the second wheel drive motor (29), preferably by a drive band (35).

10. 2. The container handling vehicle (501) according to claim 1, wherein the first coupler link (15a) and the second coupler link (15b) are configured to move in the second direction (X) toward the second wheel (8b) and the fourth wheel (8d), respectively, when the first wheel link (9) is moved from the second angular position to the first angular position.

11. 2. The container handling vehicle (501) of claim 1, wherein the first section (S1) comprises a lifting device (2) for lifting a storage container (106) and provides a cavity (26) in which the storage container (106) can be accommodated, and the second wheel (8b) and the fourth wheel (8d) are positioned on opposite sides of the cavity (26).

12. The container handling vehicle (501) of claim 11, wherein the lifting device (2) comprises at least one rotatable lifting shaft (33) configured to raise and lower the lifting frame (2) via a set of lifting bands (5), the lifting shaft being arranged in the first section (S1) above the cavity (26).

13. 12. The container handling vehicle (501) according to claim 11, further comprising a lifting drive motor (28) for driving the lifting device (2), the lifting drive motor (28) being arranged in the second section (S2).

14. 2. The container handling vehicle (501) according to claim 1, wherein the first coupler link (15a) and the second coupler link (15b) are configured to move in the second direction (X) toward the first wheel (8a) and the third wheel (8c), respectively, when the first wheel link (9) is moved from the first angular position to the second angular position.

15. 2. The container handling vehicle (501) of claim 1, wherein the first coupler link (15a) and the second coupler link (15b) are plate-shaped and provide covers that close the lower portions of the two sides of the container handling vehicle (501).

16. 2. The container handling vehicle (501) of claim 1, wherein the first swivel coupling (10) and the third swivel coupling (13) are arranged at a lower level than the second swivel coupling (11) and the fourth swivel coupling (14).

17. 2. The container handling vehicle (501) of claim 1, further comprising a rechargeable battery (30) disposed in the second section (S2).

18. 18. The container handling vehicle (501) of claim 17, further comprising a set of electrodes (31) for receiving power from a charging station, said electrodes (31) being arranged in said second section (S2) and connected to said rechargeable battery (30).

19. 2. The container handling vehicle (501) according to claim 1, further comprising a control unit (19) arranged in the second section (S2).

20. 2. The container handling vehicle (501) according to claim 1, wherein the first pair of wheels (7a, 7b), the second wheel (8b), and the fourth wheel (8d) are non-drive wheels.

21. 2. The container handling vehicle (501) of claim 1, further comprising a set of replaceable or adjustable distance pins (22), the distance pins (22) being configured to interact with a switch (32) or sensor on the lifting frame (2) when the lifting frame (2) is in the upper position.

22. 2. The container handling vehicle according to claim 1, wherein each of the second wheel links (12) comprises a first edge section (37a) extending upward from the level of the third swivel coupling (13) and a second edge section (37b) extending downward from the level of the third swivel coupling (13), the first edge section (37a) and the second edge section (37b) being oriented away from the connected first wheel link (9) and inclined relative to each other so as not to extend beyond the outer sides of the first pair of wheels when the second wheel link (12) is moved around the third swivel coupling (13).

23. 2. The container handling vehicle (501) according to claim 1, wherein the first wheel (8a) and the third wheel (8c) are arranged in the second section (S2).

24. 2. The container handling vehicle (501) according to claim 1, wherein the second wheel (8b) and the fourth wheel (8d) have a diameter (D1) smaller than a diameter (D2) of the first wheel (8a) and the third wheel (8c).

25. A storage system comprising a container handling vehicle (501) as described in any one of claims 1 to 24, said storage system further comprising a framework structure (100) having a plurality of storage columns (105) for accommodating vertical stacks of storage containers (106), and a rail system (108) above the storage columns along which the container handling vehicle (501) can move in two perpendicular directions.

26. A method of assembling a container handling vehicle (501) according to any one of claims 1 to 24, said method comprising: a) assembling the second section (S2) of the vehicle frame (6), the second section (S2) comprising the second pair of wheels (7c, 7d), the first wheel link (9), the first wheel (8a), and the third wheel (8c); b) connecting the first section (S1) of the vehicle frame (6) to the second section (S2), the first section comprising the first pair of wheels (7a, 7b), the second wheel link (12), the second wheel (8b), and the fourth wheel (8d); c) interconnecting said first wheel links (9) to respective said second wheel links (12) by said first coupler links (15a) and said second coupler links (15b); A method comprising:

27. A method of assembling a container handling vehicle (501) according to any one of claims 1 to 24, said method comprising: a) assembling the second section (S2) of the vehicle frame (6), the second section (S2) comprising the second pair of wheels (7c, 7d), the first wheel link (9), the first wheel (8a), and the third wheel (8c); b) connecting the first section (S1) of the vehicle frame (6) to the second section (S2), the first section comprising the first pair of wheels (7a, 7b), the second wheel link (12), the second wheel (8b), and the fourth wheel (8d); c) interconnecting said first wheel links (9) to respective said second wheel links (12) by said first coupler links (15a) and said second coupler links (15b); Including, The method, wherein the second section (S2) assembled in step a) comprises any of the first wheel drive motor (25), the second wheel drive motor (29), the lift drive motor (28), the actuator assembly (17, 23), the drive shaft (24), the cross member (16), and the control unit (19).

28. A method of changing the direction of travel of a container handling vehicle (501) as defined in any one of claims 1 to 24, wherein the first wheel links (9) are interconnected by a drive shaft (24) and a cross member (16), the drive shaft (24) is operatively connected to drive the first wheel (8a) and the third wheel (8c), the cross member (16) being arranged to fix the angular positions of the first wheel links (9) relative to each other, whereby the first wheel links (9) move in unison around their respective first swivel couplings (10); The method comprises: rotating the first wheel link (9), the drive shaft (24), and the cross member (16) in unison about an axis extending between the first pivot coupling (10); This causes the first wheel link (9) to move from a first angular position to a second angular position, and the second set of wheels to move from an upper position in which the container handling vehicle (501) can move in the first direction (Y) to a lower position in which the container handling vehicle (501) can move in the second direction (X).

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