Patent Publication Number: US-2023145633-A1

Title: Container handling vehicle

Description:
FIELD OF THE INVENTION 
     The present invention relates to a container handling vehicle, or robot, for picking up storage containers from a storage system, and a storage system comprising such a vehicle. 
     BACKGROUND AND PRIOR ART 
       FIG.  1    discloses a typical prior art automated storage and retrieval system  1  with a framework structure  100  and  FIGS.  2  to  4    disclose two different prior art container handling vehicles  201 , 301  suitable for operating on such a system  1 . 
     The framework structure  100  comprises upright members  102 , horizontal members  103  and a storage volume comprising storage columns  105  arranged in rows between the upright members  102  and the horizontal members  103 . In these storage columns  105  storage containers  106 , also known as bins, are stacked one on top of one another to form stacks  107 . The members  102 ,  103  may typically be made of metal, e.g. extruded aluminium profiles. 
     The framework structure  100  of the automated storage and retrieval system  1  comprises a rail system  108  arranged across the top of framework structure  100 , on which rail system  108  a plurality of container handling vehicles  201 , 301  are operated to raise storage containers  106  from, and lower storage containers  106  into, the storage columns  105 , and also to transport the storage containers  106  above the storage columns  105 . The rail system  108  comprises a first set of parallel rails  110  arranged to guide movement of the container handling vehicles  201 , 301  in a first direction X across the top of the frame structure  100 , and a second set of parallel rails  111  arranged perpendicular to the first set of rails  110  to guide movement of the container handling vehicles  201 , 301  in a second direction Y which is perpendicular to the first direction X. Containers  106  stored in the columns  105  are accessed by the container handling vehicles through access openings  112  in the rail system  108 . The container handling vehicles  201 , 301  can move laterally above the storage columns  105 , i.e. in a plane which is parallel to the horizontal X-Y plane. 
     The upright members  102  of the framework structure  100  may be used to guide the storage containers during raising of the containers out from and lowering of the containers into the columns  105 . The stacks  107  of containers  106  are typically self-supportive. 
     Each prior art container handling vehicle  201 , 301  comprises a vehicle body  201   a , 301   a,  and first and second sets of wheels  201   b , 301   b , 201   c , 301   c  which enable the lateral movement of the container handling vehicles  201 , 301  in the X direction and in the Y direction, respectively. In  FIGS.  2  and  3    two wheels in each set are fully visible. The first set of wheels  201   b , 301   b  is arranged to engage with two adjacent rails of the first set  110  of rails, and the second set of wheels  201   c , 301   c  is arranged to engage with two adjacent rails of the second set  111  of rails. At least one of the sets of wheels  201   b , 301   b , 201   c , 301   c  can be lifted and lowered, so that the first set of wheels  201   b , 301   b  and/or the second set of wheels  201   c , 301   c  can be engaged with the respective set of rails  110 ,  111  at any one time. 
     Each prior art container handling vehicle  201 , 301  also comprises a lifting device  2  (shown in  FIG.  4   ) for vertical transportation of storage containers  106 , e.g. raising a storage container  106  from, and lowering a storage container  106  into, a storage column  105 . The lifting device  2  comprises a lifting frame  3  having one or more gripping/engaging devices  4  adapted to engage a storage container  106  and guide pins  304  for correct positioning of the lifting frame  3  relative to the storage container  106 . The lifting frame  3  can be lowered from the vehicle  201 , 301  by lifting bands  5  so that the position of the lifting frame with respect to the vehicle  201 , 301  can be adjusted in a third direction Z which is orthogonal the first direction X and the second direction Y. 
     The lifting frame  3  (not shown) of the container handling vehicle  201  in  FIG.  2    is located within the vehicle body  201   a.  An advantage of this arrangement is that horizontal movement of the lifting frame  3 , due to movement and acceleration of the vehicle, is prevented by interaction with inner surfaces of the vehicle body when the lifting frame enters the vehicle body. 
     Conventionally, and also for the purpose of this application, Z=1 identifies the uppermost layer of storage containers, i.e. the layer immediately below the rail system  108 , Z=2 the second layer below the rail system  108 , Z=3 the third layer etc. In the exemplary prior art disclosed in  FIG.  1   , Z=8 identifies the lowermost, bottom layer of storage containers. Similarly, X=1 . . . n and Y=1 . . . n identifies the position of each storage column  105  in the horizontal plane. Consequently, as an example, and using the Cartesian coordinate system X, Y, Z indicated in  FIG.  1   , the storage container identified as  106 ′ in  FIG.  1    can be said to occupy storage position X=10, Y=2, Z=3. The container handling vehicles  201 , 301  can be said to travel in layer Z=0, and each storage column  105  can be identified by its X and Y coordinates. 
     The storage volume of the framework structure  100  has often been referred to as a grid  104 , where the possible storage positions within this grid are referred to as storage cells. Each storage column may be identified by a position in an X- and Y-direction, while each storage cell may be identified by a container number in the X-, Y and Z-direction. 
     Each prior art container handling vehicle  201 , 301  comprises a storage compartment or space for receiving and stowing a storage container  106  when transporting the storage container  106  across the rail system  108 . The storage space may comprise a cavity arranged centrally within the vehicle body  201   a  as shown in  FIG.  2    and as described in e.g. WO2015/193278A1, the contents of which are incorporated herein by reference. 
       FIG.  3    shows an alternative configuration of a container handling vehicle  301  with a cantilever construction. Such a vehicle is described in detail in e.g. NO317366, the contents of which are also incorporated herein by reference. 
     The central cavity container handling vehicles  201  shown in  FIG.  2    may have a footprint that covers an area with dimensions in the X and Y directions which is generally equal to the lateral extent of a storage column  105 , e.g. as is described in WO2015/193278A1, the contents of which are incorporated herein by reference. The term ‘lateral’ used herein may mean ‘horizontal’. 
     Alternatively, the central cavity container handling vehicles  201  may have a footprint which is larger than the lateral area defined by a storage column  105 , e.g. as is disclosed in WO2014/090684A1. 
     The rail system  108  typically comprises rails with grooves in which the wheels of the vehicles run. Alternatively, the rails may comprise upwardly protruding elements, where the wheels of the vehicles comprise flanges to prevent derailing. These grooves and upwardly protruding elements are collectively known as tracks. Each rail may comprise one track, or each rail may comprise two parallel tracks. 
     WO2018146304, the contents of which are incorporated herein by reference, illustrates a typical configuration of rail system  108  comprising rails and parallel tracks in both X and Y directions. 
     In the framework structure  100 , a majority of the 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 special-purpose columns used by the container handling vehicles  201 , 301  to drop off and/or pick up storage containers  106  so that they can be transported to an access station (not shown) where the storage containers  106  can be accessed from outside of the framework structure  100  or transferred out of or into the framework structure  100 . Within the art, such a location is normally referred to as a ‘port’ and the column in which the port is located may be referred to as a ‘port column’  119 , 120 . The transportation to the access station may be in any direction, that is horizontal, tilted and/or vertical. For example, the storage containers  106  may be placed in a random or dedicated column  105  within the framework structure  100 , then picked up by any container handling vehicle and transported to a port column  119 , 120  for further transportation to an access station. Note that the term ‘tilted’ means transportation of storage containers  106  having a general transportation orientation somewhere between horizontal and vertical. 
     In  FIG.  1   , the first port column  119  may for example be a dedicated drop-off port column where the container handling vehicles  201 , 301  can drop off storage containers  106  to be transported to an access or a transfer station, and the second port column  120  may be a dedicated pick-up port column where the container handling vehicles  201 , 301  can pick up storage containers  106  that have been transported from an access or a transfer station. 
     The access station may typically be a picking or a stocking station where product items are removed from or positioned into the storage containers  106 . In a picking or a stocking station, the storage containers  106  are normally not removed from the automated storage and retrieval system  1  but are returned into the framework structure  100  again once accessed. A port can also be used for transferring storage containers to another storage facility (e.g. to another framework structure or to another automated storage and retrieval system), to a transport vehicle (e.g. a train or a lorry), or to a production facility. 
     A conveyor system comprising conveyors is normally employed to transport the storage containers between the port columns  119 , 120  and the access station. 
     If the port columns  119 , 120  and the access station are located at different levels, the conveyor system may comprise a lift device with a vertical component for transporting the storage containers  106  vertically between the port column  119 , 120  and the access station. 
     The conveyor system may be arranged to transfer storage containers  106  between different framework structures, e.g. as is described in WO2014/075937A1, the contents of which are incorporated herein by reference. 
     When a storage container  106  stored in one of the columns  105  disclosed in  FIG.  1    is to be accessed, one of the container handling vehicles  201 , 301  is instructed to retrieve the target storage container  106  from its position and transport it to the drop-off port column  119 . This operation involves moving the container handling vehicle  201 , 301  to a location above the storage column  105  in which the target storage container  106  is positioned, retrieving the storage container  106  from the storage column  105  using the container handling vehicle&#39;s  201 , 301  lifting device (not shown), and transporting the storage container  106  to the drop-off port column  119 . If the target storage container  106  is located deep within a stack  107 , i.e. with one or a plurality of other storage containers  106  positioned above the target storage container  106 , the operation also involves temporarily moving the above-positioned storage containers prior to lifting the target storage container  106  from the storage column  105 . This step, which is sometimes referred to as “digging” within the art, may be performed with the same container handling vehicle that is subsequently used for transporting the target storage container to the drop-off port column  119 , or with one or a plurality of other cooperating container handling vehicles. Alternatively, or in addition, the automated storage and retrieval system  1  may have container handling vehicles specifically dedicated to the task of temporarily removing storage containers from a storage column  105 . Once the target storage container  106  has been removed from the storage column  105 , the temporarily removed storage containers can be repositioned into the original storage column  105 . However, the removed storage containers may alternatively be relocated to other storage columns. 
     When a storage container  106  is to be stored in one of the columns  105 , one of the container handling vehicles  201 , 301  is instructed to pick up the storage container  106  from the pick-up port column  120  and transport it to a location above the storage column  105  where it is to be stored. After any storage containers positioned at or above the target position within the storage column stack  107  have been removed, the container handling vehicle  201 , 301  positions the storage container  106  at the desired position. The removed storage containers may then be lowered back into the storage column  105  or relocated to other storage columns. 
     For monitoring and controlling the automated storage and retrieval system  1 , e.g. monitoring and controlling the location of respective storage containers  106  within the framework structure  100 , the content of each storage container  106 ; and the movement of the container handling vehicles  201 , 301  so that a desired storage container  106  can be delivered to the desired location at the desired time without the container handling vehicles  201 , 301  colliding with each other, the automated storage and retrieval system  1  comprises a control system  500  which typically is computerized and which typically comprises a database for keeping track of the storage containers  106 . 
     A disadvantage of the prior art container handling vehicle  301  shown in  FIGS.  3  and  4    is that horizontal movement of the lifting frame  3  is not prevented until the lifting frame  3  is fully raised and in contact with an underside of the cantilevered section  6  from which the lifting frame  3  depends. When fully raised, combined guiding pins/contact sensors  26  provided on the top side of the lifting frame  3  interact with the cantilever section  6  and restrain horizontal movement between the lifting frame  3  and the cantilever section  6 . To avoid potential errors caused by a horizontally moving lifting frame  3 , the container handling vehicle  301  in  FIGS.  3  and  4    should not move upon the rail system  108  until the lifting frame is fully raised. The time delay of having the container handling vehicle  301  standing still until the lifting frame is fully raised is minor. However, a storage system will commonly have a plurality of container handling vehicles, wherein each vehicle performs many lifting operations. Consequently, a slight time delay for each operation will add up and contribute to a less than optimal efficiency of the storage system. 
     The object of the present invention is to provide an improved container handling vehicle, wherein some of the disadvantages of the prior art vehicles featuring a cantilevered section are avoided or alleviated. 
     SUMMARY OF THE INVENTION 
     The present invention is defined by the attached claims and in the following: 
     In a first aspect, the present invention provides a container handling vehicle for lifting a storage container from an underlying framework structure, 
     the vehicle comprises a container lifting assembly for lifting the storage container and a vehicle body; 
     the container lifting assembly comprises a lifting frame for releasable connection to a storage container, a lifting shaft assembly and a plurality of lifting bands, the lifting bands are connected to the lifting frame and the lifting shaft assembly such that the lifting frame may be raised or lowered by operating the lifting shaft assembly; and 
     the vehicle body comprises a sidewall and a cantilevered section from which the lifting frame depends, the cantilevered section extends laterally from an upper end of the sidewall; wherein 
     the container lifting assembly features a lifting frame guide assembly comprising a first guide device and a cooperating second guide device; 
     the first guide device is provided on the lifting frame; and 
     the second guide device is slidably connected to the sidewall via at least one vertically extending rail, such that the second guide device can move in a vertical direction relative to the sidewall; 
     the first guide device and the second guide device are arranged to interact with each other when the lifting frame is adjacent the sidewall, such that horizontal movement of the lifting frame relative to the vehicle body is restricted. 
     In an embodiment of the container handling vehicle, the first guide device and the second guide device may be arranged to interact with each other when the lifting frame is adjacent the sidewall, such that horizontal movement of the lifting frame relative to the vehicle body is restricted or prevented. 
     The lifting bands may provide a lifting band end connected at one of four corner sections of the lifting frame. In an embodiment, the container handling vehicle may comprise four lifting bands. 
     In other words, the lifting bands may be connected to the lifting frame and the lifting shaft assembly such that the lifting frame may be raised or lowered relative to the cantilevered section by operating the lifting shaft assembly. 
     In other words, the lifting frame is suspended, or depends, from an underside of the cantilevered section. 
     In an embodiment of the container handling vehicle, the first guide device may extend upwards from the lifting frame, e.g. as a pin, or into a topside of the lifting frame, e.g. a hole. 
     In an embodiment of the container handling vehicle, the first guide device may be provided on a top side of the lifting frame. The first guide device may extend upwards from the top side of the lifting frame, e.g. as a pin, or into the topside of the lifting frame, e.g. a hole. 
     In an embodiment of the container handling vehicle, the first guide device may be connected to the lifting frame such that horizontal movement of the first guide device relative to the lifting frame is prevented. In other words, the first guide device may be fixed or rigidly connected to the lifting frame. 
     In other words, the first guide device and the second guide device may be arranged to interact and restrict or prevent horizontal movement between them when the lifting frame is adjacent the sidewall such that horizontal movement of the lifting frame relative to the vehicle body is restricted or prevented. 
     In other words, the first guide device and the second guide device may be arranged to interact with each other when the lifting frame is moving in a vertical direction adjacent the sidewall, such that horizontal movement of the lifting frame relative to the vehicle body is restricted or prevented. 
     In an embodiment of the container handling vehicle, the first guide device and the second guide device may be arranged to interact such that horizontal movement between them is restricted or prevented. 
     In an embodiment of the container handling vehicle, the second guide device may be slidably connected to the sidewall, such that horizontal movement of the second guide element relative to the sidewall is restricted or prevented. 
     In an embodiment of the container handling vehicle, the vertically extending rail may extend from a lower position on the sidewall towards the cantilevered section, such that the second guide device may move in a vertical direction between a lower position adjacent to the sidewall and an upper position adjacent to the sidewall in which upper position the lifting frame is in contact with the cantilevered section. 
     In an embodiment of the container handling vehicle, the at least one vertically extending rail may be at least one vertical rail. 
     In an embodiment of the container handling vehicle, the first guide device may comprise at least one first guide element and the second guide device may comprise at least one second guide element, wherein the first guide element and the second guide element have complementary shapes such that horizontal movement between the first guide element and the second guide element is restricted when the first guide element interact with the second guide element. The complementary shapes of a first guide element and a second guide element may have respective opposite facing surfaces which restrict or prevent horizontal movement of the complementary shapes relative to each other when the complementary shapes interact. 
     In an embodiment of the container handling vehicle, a part of the second guide device may be arranged at a position between the cantilevered section and the lifting frame. The part may comprise at least one second guide element. 
     In an embodiment of the container handling vehicle, the second guide device may be a carriage. The carriage may comprise a first part slidably connected to the sidewall by the at least one rail and a second part arranged at a position between the cantilevered section and the lifting frame. The second part may comprise at least one second guide element. 
     In an embodiment of the container handling vehicle, one of the first guide device and the second guide device may comprise at least one guide element being a pin, protrusion, recess or hole and the other one of the first guide device and the second guide device may comprise a complementary guide element for interacting with the at least one pin, protrusion, recess or hole, such that horizontal movement of the first guide device relative to the second guide device is restricted or prevented. 
     In an embodiment of the container handling vehicle, the first guide device may comprise two first guide elements being horizontally spaced, and the second guide device may comprise two second guide elements, each of the first guide elements arranged to interact with a corresponding second guide element. The spacing of the guide devices can help to react torque on the lifting frame during vehicle movements, such as during acceleration or deceleration. In another embodiment, the numbers of first and second guide elements could be different. For example, there could be two first guide elements in the form of guide pins and a second guide element in the form of a slot. 
     In an embodiment of the container handling vehicle, the first guide element may be a pin, vertical recess or hole, and the second guide element may be a hole, horizontal protrusion or pin, respectively. 
     In an embodiment of the container handling vehicle, at least one of the first guide element and the second guide element may comprise inclined surfaces for guiding the first and second guide device into interaction. 
     In an embodiment of the container handling vehicle, one of the first guide device and the second guide device may comprise at least one pin or vertical recess, and one of the first guide device and the second guide device comprises a cooperating hole or protrusion, respectively, such that horizontal movement of the first guide device relative to the second guide device is restricted or prevented. 
     In an embodiment of the container handling vehicle, one of the first guide device and the second guide device may comprise a spring or other compliant device arranged to dampen the interaction between the first guide device and the second guide device in a vertical direction. 
     In an embodiment, the container handling vehicle may comprise
         a first set of wheels arranged on opposite sides of the vehicle body, for moving the vehicle along a first direction on a rail system of the underlying framework structure;   a second set of wheels arranged on other opposite sides of the vehicle body, for moving the vehicle along a second direction on the rail system, the second direction being perpendicular to the first direction; and   the first set of wheels being displaceable in a vertical direction between a first position, wherein the first set of wheels allows movement of the vehicle along the first direction, and a second position, wherein the second set of wheels allows movement of the vehicle along the second direction.       

     In a second aspect, the present invention provides a storage system comprising a framework structure and at least one container handling vehicle according to the first aspect of the invention, wherein the framework structure comprises multiple storage columns, in which storage containers may be stored on top of one another in vertical stacks, and the container handling vehicle is operated on a rail system at a top level of the framework structure for retrieving storage containers from, and storing storage containers in, the storage columns, and for transporting the storage containers horizontally across the rail system. The rail system may be a rail grid system allowing movement of the container handling vehicle in two perpendicular directions. 
     In a third aspect, the present invention provides a method of operating a container handling vehicle in a storage system, 
     the storage system comprising a framework structure and at least one container-handling vehicle, wherein the framework structure comprises multiple storage columns, in which storage containers may be stored on top of one another in vertical stacks, and the container handling vehicle is operated on a rail system at a top level of the framework structure for retrieving storage containers from, and storing storage containers in, the storage columns, and for transporting the storage containers horizontally across the rail system, 
     the container handling vehicle comprises a container lifting assembly, for lifting the storage container, and a vehicle body; 
     the container lifting assembly comprises a lifting frame for releasable connection to a storage container, a lifting shaft assembly and a plurality of lifting bands, the lifting bands are connected to the lifting frame and the lifting shaft assembly such that the lifting frame may be raised or lowered by operating the lifting shaft assembly; and 
     the vehicle body comprises a sidewall and a cantilevered section from which the lifting frame is suspended, the cantilevered section extends laterally from an upper end of the sidewall; wherein 
     the container lifting assembly features a lifting frame guide assembly comprising a first guide device and a cooperating second guide device; 
     the first guide device is provided on the lifting frame; and 
     the second guide device is slidably connected to the sidewall via at least one vertically extending rail, such that the second guide device can move in a vertical direction relative to the sidewall; 
     the first guide device and the second guide device are arranged to interact with each other when the lifting frame is adjacent the sidewall such that horizontal movement of the lifting frame relative to the vehicle body is restricted or prevented; wherein 
     the method comprises the steps of:
         lowering a storage container into a storage column by use of the container lifting assembly;   releasing the storage container from the lifting frame;   raising the lifting frame until the first guide device interacts with the second guide device; and   moving the container handling vehicle horizontally across the rail system when a lowermost level of the lifting frame is above an uppermost level of the rail system and before the lifting frame has reached an upper position.       

     In a fourth aspect, the present invention provides a method of preventing horizontal movement of a lifting frame of a container handling vehicle, the container handling vehicle comprises a container lifting assembly, for lifting a storage container, and a vehicle body; 
     the container lifting assembly comprises a lifting frame for releasable connection to a storage container, a lifting shaft assembly and a plurality of lifting bands, the lifting bands are connected to the lifting frame and the lifting shaft assembly such that the lifting frame may be raised or lowered by operating the lifting shaft assembly; and
         the vehicle body comprises a sidewall and a cantilevered section from which the lifting frame is suspended, the cantilevered section extends laterally from an upper end of the sidewall;       

     the container lifting assembly features a lifting frame guide assembly comprising a first guide device and a cooperating second guide device; 
     the first guide device is provided on the lifting frame; and 
     the second guide device is slidably connected to the sidewall via at least one vertically extending rail, such that the second guide device can move in a vertical direction relative to the sidewall; 
     wherein the method comprises the steps of:
         raising the lifting frame from a level below the container handling vehicle to a first position in which interaction between the first guide device and the second guide device is initiated; and   raising the lifting frame from the first position to a second position in which the first guide device and the second guide device interact with each other and horizontal movement of the lifting frame relative to the vehicle body is restricted or prevented.       

     In an embodiment, the method according to the fourth aspect comprises a step of:
         raising the lifting frame from the second position to a third position, while the second guide device is simultaneously moved up the vertically extending rail by the lifting frame, the first guide device simultaneously interacting with the second guide device to restrict horizontal movement of the lifting frame relative to the vehicle body.       

     In the second and third positions, and in positions between the second and third positions, the lifting frame may be at a level allowing horizontal movement of the container handling vehicle. In the third position, the lifting frame may be in contact, or docking, with the cantilevered section. 
     In the third and fourth aspect of the invention, the container handling vehicle may be according to any of the embodiments of the first aspect. 
     The term “sidewall” is intended to mean a side section of the vehicle body. The side section may comprise a cover plate but may also be a framework structure. The side section may be substantially vertical. 
     The term “horizontal movement” is intended to comprise bot lateral and rotational horizontal movement. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention is described in detail by reference to the following drawings: 
         FIG.  1    is a perspective view of a framework structure of a prior art automated storage and retrieval system. 
         FIG.  2    is a perspective view of a prior art container handling vehicle having a centrally arranged cavity for carrying storage containers therein. 
         FIG.  3    is a perspective view of a prior art container handling vehicle having a cantilevered section for carrying storage containers underneath. 
         FIG.  4    are side views of the container handling vehicle in  FIG.  3   , wherein a lifting device is shown. 
         FIGS.  5 - 8    are perspective side views of a first exemplary container handling vehicle according to the invention. 
         FIGS.  9 - 11    are perspective side views of a second exemplary container handling vehicle according to the invention. 
         FIG.  12    is a perspective topside view of the container handling vehicle in  FIGS.  9 - 11   . 
         FIGS.  13 - 16    are perspective side views of a third exemplary container handling vehicle according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following, embodiments of the invention will be discussed in more detail with reference to the appended drawings. However, the drawings are not intended to limit the invention to the subject-matter depicted in the drawings. 
     The present invention is a remotely operated container handling vehicle for use in an automated storage system featuring at least one rail system, e.g. a rail system  108  as discussed for the prior art storage system disclosed in  FIG.  1   . 
     Different exemplary embodiments of a container handling vehicle  10 - 10 ″ according to the invention are shown in  FIGS.  5 - 16   . The vehicles  10 - 10 ″ are for picking up storage containers  106  in an automated storage system  1 , e.g. as shown in  FIG.  1   , by use of a container lifting assembly  3 , 5 , 7   a , 7   b.  The container lifting assembly features a lifting frame  3  for releasable connection to a storage container  106 , a lifting shaft assembly  7   a , 7   b  (see  FIG.  12   ) and four lifting bands  5 . The lifting bands  5  are connected to the lifting frame  3  and the lifting shaft assembly  7   a , 7   b  such that the lifting frame  3  may be raised or lowered by operating the lifting shaft assembly. 
     The container handling vehicles  10 - 10 ″ have a vehicle body  8  comprising a sidewall  9  and a cantilevered section  6 . The lifting frame  3  is suspended from the cantilevered section  6  which extends laterally from an upper end  11  of the sidewall  9 . As in the prior art vehicles, the lifting frame features combined guiding pins/contact sensors  26  arranged on the top side of the lifting frame  3  (see  FIG.  5   b   ). The guiding pins/contact sensors  26  interact with the cantilever section  6  when the lifting frame is fully raised and restrain horizontal movement between the lifting frame  3  and the cantilever section  6 . 
     To restrict horizontal movement of the lifting frame  3  during movement of the container handling vehicles  10 - 10 ″, each of the container handling vehicle  10 - 10 ″ features a lifting frame guide assembly having a first guide device  12 - 12 ″ and a cooperating second guide device  13 - 13 ″. The first guide device  12 - 12 ″ features at least one first guide element  15 , 17 , 24 , and the second guide device  13 - 13 ″ features at least one second guide element  16 , 18 , 25 , wherein the first and second guide elements have complementary shapes. The complimentary shapes are designed to restrict horizontal movement, i.e. both lateral and rotational horizontal movement, between the first and the second guide element when the guide elements interact with each other. 
     The second guide device  13 - 13 ″ of the lifting frame guide assembly may be described as a carriage (e.g. made up of plate sections  22   a , 22   b,  see below) slidably connected to the sidewall  9 , e.g. via at least one rail  19 , 19 ′. The carriage couples with the lifting frame  3  via the first guide device  12 - 12 ″ and moves with the lifting frame  3  as the lifting frame  3  moves from a position below the halfway point up to where the lifting frame docks with the cantilever section. 
     The complimentary shapes of the first guide element  15 , 17 , 24  and the second guide element  16 , 18 , 25  serve to locate the first guide device  12 - 12 ″ and the second guide device  13 - 13 ″ together as the lifting frame  3  is raised and emerges from the storage grid, e.g. from a storage column  105  as shown in  FIG.  1   . The complimentary shapes may be of any shape or form provided the first and second guide device are restrained from horizontal movement relative to each other when located together. When positioned within the storage column  105 , horizontal movement of the lifting frame  3  is restricted by the inner periphery of the storage column  105 . When the lifting frame  3  emerges from the storage column  105 , horizontal restraint of the lifting frame  3  is provided by the second guide device  13 - 13 ″ locking down the horizontal movement through connection with the first guide device  12 - 12 ″. 
     A first exemplary embodiment of a container handling vehicle  10  according to the invention is shown in  FIGS.  5 - 8   . 
     The first guide device  12  of the first exemplary embodiment comprise two vertical pins  15  (i.e. first guide elements) arranged on a top side  14  of the lifting frame  3 . The two pins  15  are connected to the lifting frame  3  such that horizontal movement of the pins relative to the lifting frame  3  is prevented. 
     The second guide device  13  comprises two holes  16  (i.e. second guide elements), each hole being sized to accommodate one of the vertical pins  15  of the first guide device  12 . The second guide device  13  is slidably connected to the sidewall  9  via two rails  19  and can move in a vertical direction relative to the sidewall  9 . A part of the second guide device  13  featuring the two holes  16  extends laterally from the sidewall  9  and at a position between the cantilevered section  6  and the lifting frame  3 . In this embodiment, the second guide device is made up of a first plate section  22   a  and a second plate section  22   b.  The first plate section  22   a  is connected to the rails  19 , and the second plate section  22   b  features the two holes  16  and extends from an upper end of the first plate section  22   a  and between the cantilevered section  6  and the lifting frame  3 . 
     The pins  15  and holes  16  are arranged to interact with each other, i.e. each of the pins  15  is accommodated in a corresponding hole  16 , when the lifting frame  3  is adjacent the sidewall  9  such that horizontal movement of the lifting frame  3  relative to the vehicle body  8  is restricted. By having two pins  15  and complimentary holes  16  rotational horizontal movement, i.e. twisting, of the lifting frame relative to the vehicle body  8  is restricted. 
     It is noted that the circular peripheries (i.e. the complimentary shapes) of the pins  15  and the holes  16  necessitate the solution of having two of each to restrict rotational movement of the lifting frame relative to the vehicle body  8 . However, in other embodiments of the invention, having at least two first guide elements and at least two complimentary second guide elements are not essential for restricting the rotational movement. In other embodiments, rotational movement may for instance be restricted by designing the first guide element as a pin/protrusion having a square or rectangular peripheral shape, and the second guide element as a cooperating hole having a complimentary square or rectangular peripheral shape. In general, to restrict rotational horizontal movement between the lifting frame and the vehicle body while having a single first guide element and a single second guide element it may be sufficient to provide the first and second guide elements with complimentary non-circular peripheral shapes. 
     To avoid excessive noise and wear, and potentially reduce any risk of the first and second guide device being jammed, a spring  20  or other compliant device is arranged around each of the pins  15  to dampen the interaction between the first and the second guide device  12 , 13  and the lifting frame  3 . 
     By having the second guide device  13  slidably connected to the sidewall  9  of the vehicle body  8 , the lifting frame  3  can be raised from a lower position close to the rail system  108  where it emerges from the lateral constraints of the grid, to a higher position adjacent the sidewall  9  while horizontal movement of the lifting frame  3  is restricted or prevented. The lowermost level of the lifting frame  3  when in the lower position is above an uppermost level of a rail system  108  upon which the container handling vehicle is arranged, see  FIG.  7   . In the upper position, the lifting frame is fully raised towards the cantilevered section  6 . 
     Thus, due to the lifting frame guide assembly  12 , 13 , the container handling vehicle according to the invention may start to move upon the rail system  108  as soon as the lifting frame is in the lower position, e.g. after storing a storage container  106  in a storage column  105 . In most instances when the lifting frame is not connected to a storage container  106 , the lifting frame is kept in the lower position while the container handling vehicle moves upon the rail system  108 . In this manner time and energy is also saved by not requiring the lifting frame to be lifted between the cantilever section and the lower position when a storage container is to be retrieved. The lifting frame guide assembly  12 , 13  will also ensure that the container handling vehicle  10  can move upon the rail system  108  as soon as a storage container connected to the lifting frame  3  is lifted above the rail system  108 , see  FIG.  8   . The latter feature is advantageous when the container handling vehicle is used in a storage system comprising storage containers of different heights, since a storage container being lower than the maximum storage container height may be lifted clear of the rail system before the lifting frame is at its upper position in contact with the cantilever section. 
     In view of the prior art cantilevered container handling vehicle  301 , as shown in  FIGS.  3  and  4   , the container handling vehicle  10  of the invention is more efficient in that less time is required to perform multiple container lifting/storage operations. A prior art container vehicle  301  is not allowed to move upon a rail system  108  until its lifting frame  3  is fully raised into contact with the cantilevered section. 
     To allow movement of the container handling vehicle  10  upon the rail system  108 , the vehicle  10  features a first set of wheels  21   a  arranged to allow movement of the vehicle along a first direction of the rail system  108  as shown in  FIG.  1   , e.g. along rails extending in a first direction X, and a second set of wheels  21   b  arranged to allow movement of the vehicle in a second direction, e.g. along rails extending in a second direction Y. 
     A second exemplary embodiment of a container handling vehicle  10 ′ according to the invention is shown in  FIGS.  9 - 12   . 
     The container handling vehicle  10 ′ is identical to the first exemplary container handling vehicle  10  in  FIGS.  5 - 8    apart from the design of the first guide device  12 ′ and the cooperating second guide device  13 ′. 
     The first guide device  12 ′ comprises two vertical recesses  17  (i.e. first guide elements) arranged at a top side  14  of the lifting frame  3 . The second guide device  13 ′ comprises two protrusions  18  (i.e. second guide elements), each protrusion  18  being sized to be accommodated in one of the vertical recesses  17  of the first guide device  12 ′. The second guide device  13 ′ is slidably connected to the sidewall  9  via two rails  19  and can move in a vertical direction relative to the sidewall  9 . A part of the second guide device  13 ′ featuring the two protrusions  18  extends laterally from the sidewall  9  and is positioned between the cantilevered section  6  and the lifting frame  3 . A spring  20 ′ or other compliant device is arranged in each of the recesses  17  to dampen the interaction between the first and the second guide device  12 ′, 13 ′ and the lifting frame  3 . 
     A third exemplary embodiment of a container handling vehicle  10 ″ according to the invention is shown in  FIGS.  13 - 16   . 
     The container handling vehicle  10 ″ is identical to the first and second exemplary container handling vehicles  10 , 10 ′ in  FIGS.  5 - 12    apart from the design of the first guide device  12 ″ and the cooperating second guide device  13 ″. The first guide device  12 ″ comprises two vertical sleeves  23  positioned in the lifting frame  3  providing two holes  24  (i.e. first guide elements) at the top side  14  of the lifting frame  3 . The second guide device  13 ″ comprises two pins  25  (i.e. second guide elements), each pin  25  being sized to be accommodated in one of the complementary holes  24  of the first guide device  12 ″. The second guide device  13 ″ is slidably connected to the sidewall  9  via a rail  19  and can move in a vertical direction relative to the sidewall  9  while restricted from horizontal movement relative to the sidewall  9 . A part of the second guide device  13 ″ featuring the two pins  25  extends laterally from the sidewall  9  and is positioned between the cantilevered section  6  and the lifting frame  3 . A spring (not shown) may be arranged around each of the pins  25 , or alternatively within each of the sleeves  23 , to dampen the interaction between the first and the second guide device  12 ″, 13 ″ and the lifting frame  3 . 
     The present invention is described by three specific combinations of guide elements, i.e. pin/hole and protrusion/recess, for restricting a horizontal movement of the lifting frame. However, based on the present disclosure multiple alternative combinations of guide elements having complimentary shapes providing a restricted horizontal movement may easily be envisioned.