Patent Publication Number: US-2023140603-A1

Title: Device for picking and/or depositing items for automated warehouses

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of realizing automated systems for storing items, or automated warehousing, preferably of boxed items. 
     In particular, the invention relates to a device for picking or depositing an item, preferably a boxed item, from or into a location in a warehouse in an automated storage system of items. 
     BACKGROUND ART 
     The use of automated devices capable of moving items between different points/locations of the system is known in the field of storage systems for items. 
     Typically, the systems constitute of a storage area strictly speaking, or warehouse, comprising multiple positioning compartments of the items, e.g., defined by shelves arranged side-by-side and/or superimposed, one or more feeding areas of the warehouse, in which the items to be stored are positioned, and one or more outfeed areas of the items picked from the warehouse. 
     The movement between the various locations of the system is carried out, according to the background art, by appropriate autonomous devices for picking and/or depositing said items. 
     The devices of the known type are appropriately shaped to pick/unload the item from a compartment/shelf and transport it to a picking point and, vice versa, to take it from a picking point to the compartment/shelf into which the item is loaded. 
     The devices of known type have an area for temporarily laying the item during its movement, e.g., a platform. 
     The device moves along main and preferential directions between the warehouse aisles. Preferably, the storage compartments/shelves are arranged on the sides of the aisle, on the right and/or on the left relative to the main direction of advancement of the device. 
     The device moves along the aisles by means of wheels moved by one or more electric motors powered by super-capacitors and batteries (e.g., lithium) positioned aboard the device itself. Alternatively, a motor power supply system can be provided by means of power bars placed on the floor of the aisle. A brush in contact with the power bar transfers the electrical energy to power the electrical parts aboard the device. 
     Indeed, in addition to the movement along the aisles, the device is also equipped with two forks that can be moved along a direction perpendicular to said main direction. The two forks have a telescopic configuration formed by sections, also named stages, which allow both the extension of the forks to enter a warehouse location and their subsequent retraction for extracting them, during the loading or unloading of the item into or from the warehouse. 
     The last stage of each fork is provided with movable elements, also named fingers, positionable in a retracted neutral position and in a protruding operating position relative to the fork, the function of which is to feed/push the box from the compartment to the device platform or, vice versa, to push the box from the device platform to the storage compartment. Appropriate motors fitted aboard the forks allow the movement of the fingers between the neutral and operating position and vice versa. 
     However, the loading/unloading devices of known type have some drawbacks. 
     A first drawback of such systems is in the need to reach the motors fitted aboard the forks, which allow the movement of the fingers, by means of wiring of multiple cables for powering and/or controlling the forks, typically by means of cable chains. The result is a high level of construction complexity, which has a negative impact both during the construction of the device and in possible later maintenance and/or replacement operations. 
     Furthermore, the presence of cables and cable chains increases the overall dimensions of the moving parts and generally implies larger dimensions, to the detriment of the compactness of the device. 
     Furthermore, since the forks are continuously moved back and forth telescopically during operation, the aforesaid cables are also subject to continuous movement. This adversely affects the system reliability, in terms of possible wear of the moving parts, possible wear of the cables and/or possible detachment between the interconnecting areas of the cables, e.g., of the electrical connection terminals. 
     An example of a device of the background art is described in WO2015/038999 A2. However, such a device inconveniently only allows its forks to be extended at the same time and only on one side for moving the boxes and thus does not allow the boxes to be moved symmetrically on two opposite warehouse aisles. Furthermore, the space to accommodate the boxes is inconveniently cluttered by the motor and motor control electronics. 
     It is an object of the present invention to overcome the drawbacks of the prior art at least in part. 
     In particular, it is an object of the present invention to suggest a loading/unloading device for automatic warehouses, which makes it possible to reduce the construction complexity relative to devices of known type. 
     It is an object of the present invention to suggest a loading/unloading device for automatic warehouses, which makes it possible to reduce the assembly times and/or costs relative to devices of known type. 
     It is a further object of the present invention to suggest a loading/unloading device for automatic warehouses, which makes it possible to increase the reliability relative to devices of known type. 
     SUMMARY 
     In a first aspect thereof, the present invention thus relates to a device for picking or depositing an item from or into a compartment of an automated warehouse, said device comprising:
         a supporting structure provided with first moving means suitable to move said device along a main direction within said warehouse:   a temporary resting zone for said item;   primary electrical power supply means for said device connected to said supporting structure;   a pair of forks facing each other comprising second moving means suitable to move said forks relative to said supporting structure in at least a transverse direction relative to said main direction between a retracted position at said temporary resting zone and an extended position in the direction of said compartment, each fork of said pair of forks comprising an end section provided with at least one thrust element positionable in at least one operating position, in which said thrust element can rest on said item and in at least one idle position in which said thrust element does not interfere with said item, said end section comprising third moving means for moving said at least one thrust element;   a central control unit integral with said supporting structure;       

     wherein said end section comprises a peripheral control unit for said third moving means, said peripheral control unit and said central control unit being configured for wireless communication with each other, and wherein said end section comprises rechargeable secondary electrical power supply means suitable to power to said peripheral control unit and said third moving means. 
     In a preferred embodiment, the rechargeable secondary electrical power supply means are suitable to be recharged with the energy provided by the primary electrical power supply means when the forks are positioned in a predetermined recharging position relative to the supporting structure. 
     According to a preferred embodiment of the invention, said predetermined recharging position corresponds to the retracted position of the forks. 
     Preferably, the rechargeable secondary electrical power supply means comprise at least one super-capacitor. 
     In a preferred embodiment, the device comprises electrical interconnection means between the secondary electrical power supply means and the primary electrical power supply means. 
     According to a preferred embodiment of the invention, the electrical interconnection means comprise sliding contacts. 
     Preferably, the transverse direction of movement of the forks is a direction perpendicular to the main direction of movement of the device. 
     In a preferred embodiment, the primary electrical power supply means comprise one or more super-capacitors and/or lithium batteries. 
     According to a preferred embodiment of the invention, the primary electrical power supply means comprise a system, which receives electrical energy by means of the sliding contact with one or more fixed electrical bars of said warehouse. 
     Preferably, the device further comprises adjustment means for adjusting the mutual distance between the pair of forks. 
     In a preferred embodiment, the operating position of the thrust element is a horizontal position and/or the idle position of the thrust element is a vertical position. 
     According to a preferred embodiment of the invention, the thrust element is positionable between the operating position and the idle position by rotation. 
     Preferably, the end section further comprises sensor means for detecting the position of the thrust element. 
     In a preferred embodiment, the central control unit comprises a second unit interposed between the central control unit and the peripheral control unit, said second unit being suitable to send command signals for operating said third moving means. 
     Preferably, the communication between said second unit and said central control unit is wired communication. 
     In a variant embodiment, the communication between said second unit and said central control unit is wireless communication. 
     In another aspect, the present invention relates to an automated storage system comprising a warehouse comprising one or more compartments for receiving an item to be stored and at least one device for picking or storing an item from or into one of said compartments, wherein the device is implemented as described above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To better understand the features and advantages of the invention, a non-limiting example of a practical embodiment is described below with reference to the accompanying drawings, in which: 
         FIG.  1    shows a diagrammatic view of an automated warehouse and a picking or depositing device in a first operating position according to a preferred embodiment of the present invention; 
         FIG.  2    shows the automatic warehouse in  FIG.  1   , in which the picking or depositing device is in an operating position; 
         FIG.  3    shows an axonometric view of the device in  FIG.  1    in a first operating position; 
         FIG.  4    shows a side plan view of the device in  FIG.  3   ; 
         FIG.  5    shows a plan view from the bottom of the device in  FIG.  3   ; 
         FIG.  6    shows the device in  FIG.  3    with some elements removed; 
         FIG.  7    shows a plan view from the right of the device in  FIG.  6   ; 
         FIG.  8    shows an axonometric view of the device in  FIG.  3    in a second operating position; 
         FIG.  9    shows a magnified detail of  FIG.  8   ; 
         FIG.  10    shows the device in  FIG.  8    with the thrust elements lowered; 
         FIG.  11    shows a magnified detail of  FIG.  4   ; 
         FIG.  12    shows the enlarged detail of  FIG.  11    with the gripping element lowered; 
         FIG.  13    shows a diagrammatic block view of the system in  FIG.  1   ; 
         FIG.  14    shows a variant embodiment of the block chart in  FIG.  13   . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Although the present invention is described below with reference to a detailed description of the embodiments shown in the drawings, the present invention is not limited to the embodiments described hereinafter and shown in the drawings. On the contrary, the embodiments described and represented clarify some aspects of the present invention. 
     The present invention has proved to be particularly advantageous with reference to the making of a picking or depositing device which moves in a warehouse in an autonomous and self-powered manner, as illustrated in greater detail below. 
     It is worth noting that the present invention is not limited to the making of autonomous and self-powered device. On the contrary, the present invention is conveniently applied to all cases which envisage the use of a device, which moves in an appropriately powered warehouse, e.g., a power supply system on fixed guides on which the device rests. 
       FIG.  1    diagrammatically shows an automatic storage system  1  for items S comprising a warehouse  10  and a picking or depositing device  20  according to a preferred embodiment of the invention. 
     The warehouse  10  illustrated in the figures by way of example has a simple layout and preferably comprises two rows  12 A,  12 B of three compartments  14  arranged laterally relative to a central aisle  16 , i.e., a first row  12 A of three compartments  14  arranged to the right of the central aisle  16  and a second row  12 B of three compartments  14  arranged to the left of the central aisle  16 . 
     The warehouse  10  further preferably comprises a loading/unloading location  18  of the items S, i.e., an area on which an item S to be stored in a predetermined compartment  14  of the warehouse  10  is placed or an area on which an item S to be picked from a compartment  14  of the warehouse  10  is placed. 
     An item S is advantageously moved in the system  1  by the picking or depositing device  20  according to the invention, henceforth referred to as device  20  for the sake of simplicity of presentation. 
     Preferably, the moving of the item S in the system  1  comprises moving the item S from the loading/unloading location  18  to a compartment  14  or, vice versa, from a compartment  14  to the loading/unloading location  18 . In variant embodiments, the movement can also provide displacing an item S between two compartments  14  of the warehouse  10 , either within the same first row  12 A, or second row  12 B, or from the first row  12 A to the second row  12 B and vice versa. 
     The device  20  according to the invention preferably allows the moving of box-shaped items S (i.e., preferably boxed items S, as shown in a simplified manner in  FIG.  1   ). 
     The device  20  comprises a supporting structure  21 , or frame, on which a resting zone  22  is defined for temporarily resting the item S during its movement, e.g., as shown in  FIG.  3   . In the illustrated embodiment, the resting zone  22  comprises a pair of supporting bars  22 A,  22 B. Preferably, respective feeding belts  24 A,  24 B are wound on the supporting bars  22 A,  22 B to promote the positioning of the item S on the device  20 , as illustrated in greater detail below. A central row of rolling rollers  25  is also present on the resting zone  22 . 
     The feeding belts  24 A,  24 B are preferably moved by motorized means  24 C and  24 D, shown in  FIG.  6   , preferably comprising an electric motor, more preferably of the brushless type. 
     The device  20  is firstly provided with first moving means  23  suitable to move the device  20  along the aisle  16  in a main direction X. 
     Preferably, the first moving means  23  comprise wheels  240 A,  240 B driven by one or more electric motors  26 , in case in point two electric motors  26  associated with two of the wheels  240 A, or drive wheels  240 A (as shown in  FIG.  6   ). 
     In a preferred embodiment, the device  20  comprises main electrical power supply means  28 , or primary electrical power supply means, fitted aboard the device  20  to make the device  20  autonomous and self-powered. 
     In a preferred embodiment, the main electrical power supply means  28  comprise super-capacitors and/or batteries  30 , e.g., lithium batteries, positioned in the headers  32 A,  32 B of the device  20  and connected to the frame  21 . 
     In an alternative implementation solution, a power supply system of the motors can be provided by means of power bars placed on the floor along the aisle and a brush aboard the device which, placed in continuous contact with the power bar, transfers the electrical power supply for the parts aboard the device. 
     A central control unit  80  is integrally associated with the frame  21  of the device  20 . The central unit  80  controls all moving parts of the device  20 . Preferably, the central unit  80  communicates with a system management unit U, as diagrammatically shown in  FIGS.  13  and  14   , on which a warehouse software manages the operation of the system  1  and in particular the movements of the device  20  in the warehouse  10 . The communication between the central unit  80  and the system management unit U is preferably wireless communication. 
     The central unit  80  is powered by said main electrical power supply means  28  and is preferably positioned in the first header  32 A of the device  20 . 
     Furthermore, the device  20  preferably comprises two forks  34 A,  34 B suitable to move along a second direction Y. The second direction Y is preferably transverse to said main direction X, more preferably perpendicular to said main direction X. 
     The two forks  34 A,  34 B face each other, preferably parallel, to define a predetermined mutual distance. Preferably, the device  20  is provided with adjustment means  40  ( FIG.  6   ) for the distance between the two forks  34 A,  34 B, or pitch, which advantageously adjusts the distance of the forks  34 A,  34 B as a function of the size of the box S to be handled, e.g., the adjustment in a range between 300 and 800 mm. In the device as shown in  FIG.  6   , the pitch is adjusted by toothed belts (not shown), preferably driven by an electric motor (preferably, but not exclusively, of the brushless type)  34 C, which feed the forks  34 A,  34 B as needed. 
     Preferably, the two forks  34 A,  34 B have a telescopic configuration formed by three sections  341 A,  342 A,  343 A,  341 B,  342 B,  343 B, referred to below as stages, which move telescopically along the second direction Y (see  FIG.  8   ). A different number of stages, or even just one, can be provided in variants. 
     The forks  34 A,  34 B are movable/extendable along the second direction Y to be inserted inside a compartment  14  of the warehouse  10 , e.g., as shown in  FIG.  2   . 
     Secondary moving means  35 A,  35 B (see  FIG.  6   ) allow the moving of forks  34 A,  34 B along the second direction Y. Preferably, the second moving means  35 A,  35 B comprise motors  36 A,  36 B (see  FIG.  6   ) associated with a pinion-rack mechanism. Equivalent moving means can be provided as a variant, e.g., a belt system, chain system, etc. 
     As unequivocally shown in the accompanying  FIGS.  3 ,  6 ,  10 , and  11   , according to an advantageous embodiment, a first motor  36 A of such motors  36 A,  36 B is operatively connected to one (the left fork  34 A) of the two forks  34 A,  34 B and a second separate motor  36 B is operatively connected to the other (the right fork  34 B) of the two forks  34 A,  34 B, so that the first motor  36 A is suitable to move one of the two forks  34 A,  34 B independently of the other of the two forks  34 A,  34 B. In particular, the first motor  36 A is suitable to move the left fork  34 A and the second motor  36 B is suitable to move the right fork  34 B independently of the movement of the left fork  34 B. 
     In a preferred embodiment, the two forks  34 A,  34 B are conformed to be able to be extended from both sides of the device  20 , e.g., towards the right side or towards the left side with reference to  FIGS.  1  and  2    to be able to reach all the compartments  14  to the right and to the left relative to the central aisle  16  of the warehouse  10 . In other words, the two forks  34 A,  34 B are both extendable towards the right side of the device, facing the first row  12 A, and towards the left side of the device facing the row  12 B of the warehouse, thus along both directions of the second direction Y. 
     Therefore, in particular, the second moving means  35 A,  35 B allow moving the forks  34 A,  34 B in both directions along the second direction Y. 
     In a preferred embodiment, the magnitude of the movements and/or the magnitude of the extensions of the forks  34 A,  34 B along the second direction Y is managed by means of the encoder measuring the rotation of the motor  36 A,  36 B. For example, the entity of the displacement is related to the motor rotation  36 A,  36 B with a fixed value (mm per motor revolution). 
     The forks  34 A,  34 B are connected to the frame  21  by means of a supporting structure  33 A,  33 B (see  FIG.  4   ) preferably comprising a pair of uprights  331 A,  332 A,  331 B,  332 B (shown in  FIG.  4   , but partially shown in  FIGS.  3 ,  4 ,  6 ,  7 ,  8 ,  11  and  12   ). It is worth noting that some reference numerals shown within the present description are not shown in the figures because the respective elements are not clearly visible. However, the position and construction of such non-visible elements can be easily inferred because they refer to elements of one fork that can be easily associated with the corresponding visible elements of the other fork, the two forks being made specularly with the same type of elements. 
     The last stage  343 A,  343 B of the two forks  34 A,  34 B, seen in greater detail in  FIGS.  8  and  9   , is preferably planar or plate-shaped, positioned vertically to be placed laterally relative to the item S, more preferably laterally with respect to the vertical walls of the box S, in the case of items packaged in a box S. 
     The last stage  343 A,  343 B constituting each of the forks  34 A,  34 B is provided with at least one thrust element  50 A,  51 A,  52 A,  50 B,  51 B,  52 B, also named finger (see in particular  FIGS.  8  and  10   ), the function of which is to push/pull the box S from the compartment  14  of the warehouse  10  to the temporary resting zone  22  of the device  20  or to push the box S from the temporary resting zone  22  of the device  20  to the compartment  14  of the warehouse  10  (it is worth noting that some of said fingers are not completely visible in the figures). 
     Each finger  50 A,  51 A,  52 A,  50 B,  51 B,  52 B is positionable in a retracted, preferably vertical, idle position, e.g., as shown in  FIGS.  3 ,  6 ,  8 , and  11   , and in a lowered, preferably horizontal, operating position, as shown for example in  FIGS.  10  and  12   . 
     Each of the fingers  50 A,  51 A,  52 A,  50 B,  51 B,  52 B is associated with third moving means for allowing rotation of the finger  50 A,  51 A,  52 A,  50 B,  51 B,  52 B between its idle and operating positions. The third moving means comprise motor means  54 A,  55 A,  56 A,  54 B,  55 B,  56 B, comprising electric motors (preferably brushless type), e.g., shown in  FIGS.  7  and  9   . 
     According to the preferred illustrated embodiment, the positioning between the idle and operating positions of each finger occurs preferably by rotation. Equivalent embodiments can be provided as variants, e.g., by means of elements associated with the last stage which protrude telescopically from the last stage. 
     According to the preferred embodiment shown in the figures, each end stage  343 A,  343 B comprises three fingers  50 A,  51 A,  52 A,  50 B,  51 B,  52 B. 
     Preferably, the first pair of facing fingers  50 A,  50 B in their lowered operating position allows the feeding of the box S from a compartment  14  on the right of the warehouse  10  to the temporary resting zone  22  of the device  20  or allows the thrust of the box from the temporary resting zone  22  of the device  20  to a compartment  14  on the left of the warehouse  10 ; the second pair of facing fingers  51 A,  51 B in their lowered operating position allows the feeding of the box S from a compartment  14  on the left of the warehouse  10  to the temporary resting zone  22  of the device  20  or allows the thrust of the box from the temporary resting zone  22  of the device  20  to a compartment  14  on the right of the warehouse  10 ; the third pair of facing fingers  52 A,  52 B is optionally present and depends on how the warehouse  10  is made, i.e. if there is a box S or there are two boxes positionable at different depths in the compartments  14 . 
     The essential steps of picking of a box S from the warehouse  10  provide:
         moving the device  20  along the main direction X until it reaches the position at the compartment  14  of the warehouse  10  where the box S to be picked is stored:   extending the forks  34 A,  34 B along the second direction Y by a length sufficient to cover the box S;   lowering the first pair of fingers  50 A,  50 B;   retracting the forks  34 A,  34 B while the fingers  50 A,  50 B feed/push the box S towards the temporary resting zone  22 .       

     Preferably, during the last step, the feeding of the box S towards the temporary resting zone  22  is promoted by the actuation of the underlying feeding belts  24 A,  24 B, and the resting on the rolling rollers  25 . 
     Similarly, the essential steps of loading of a box S from the warehouse  10  provide:
         moving the device  20  with the box S aboard along the main direction X until it reaches the position at the compartment  14  of the warehouse  10  in which the box S must be stored:   lowering the second pair of fingers  51 A,  51 B;   extending the forks  34 A,  34 B along the second direction Y by a length sufficient to insert the box S into the compartment  14  while the fingers  51 A,  51 B push the box S;   retracting the forks  34 A,  34 B, and the fingers  51 A,  51 B.       

     The thrust step is preferably promoted by actuating the underlying feeding belts  24 A,  24 B, and by resting on the rolling rollers  25 . 
     According to an aspect of the present invention, the last stage  343 A,  343 B of the fork  34 A,  34 B comprises a motor control unit  90 A,  90 B, or peripheral unit or slave unit, operatively connected to the motor means  54 A,  55 A,  56 A,  54 B,  55 B,  56 B of each finger  50 A,  51 A,  52 A,  50 B,  51 B,  52 B, as shown in  FIG.  7    for the right-hand fork  34 B only. 
     The slave unit  90 A,  90 B receives information from the central unit  80  for managing movement of the fingers  50 A,  51 A,  52 A,  50 B,  51 B,  52 B. The communication between the slave unit  90 A,  90 B, and the central unit  80  is advantageously a wireless communication. 
     The slave unit  90 A,  90 B is preferably connected to the motor means  54 A,  55 A,  56 A,  54 B,  55 B,  56 B by means of respective motor boards  60 A,  61 A,  62 A,  60 B,  61 B,  62 B, as also diagrammatically shown in  FIG.  13   . 
     Each of the boards  60 A,  61 A,  62 A,  60 B,  61 B,  62 B is preferably connected to the corresponding motor  54 A,  55 A,  56 A,  54 B,  55 B,  56 B and to the slave board  90 A,  90 B through a flat cable  92 A,  92 B, which runs longitudinally through the end stage  343 A,  343 B of the fork  34 A,  34 B; the slave board  90 A,  90 B thus comprises at least “n” output ports, where “n” corresponds to the number of fingers  50 A,  51 A,  52 A,  50 B,  51 B,  52 B (three for the embodiment illustrated and described herein). 
     According to an embodiment, the movement of one or more motors  54 A,  55 A,  56 A associated with the command of one or more thrust elements  50 A,  51 A,  52 A of one  34 A of the two forks is synchronized with the movement of one or more motors  54 B,  55 B,  56 B associated with the command of one or more thrust elements  50 B,  51 B,  52 B of the other  34 B of the two forks. 
     In particular, the central unit  80  is configured to send a first command signal to each slave board  90 A,  90 B, containing a datum relative to the specific motor  54 A,  55 A,  56 A,  54 B,  55 B,  56 B to be commanded, and possibly to the position that the relative thrust element  50 A,  51 A,  52 A,  50 B,  51 B,  52 B must reach. Furthermore, the central unit  80  is configured to send a second command signal containing the same datum as the first command signal to each slave board  90 A,  90 B. The central unit  80  is configured to send the first command signal wirelessly at a predetermined radio signal frequency (e.g., at a frequency suitable to a signal according to the Bluetooth standard, e.g., about 2.4 GHz). Furthermore, the central unit  80  is configured to send the second command signal wirelessly at a second predetermined radio signal frequency that is lower than the predetermined radio signal frequency of the first signal, such as a radio communication frequency of less than 1 GHz, e.g., at a carrier frequency of 868 MHz (FSK) or 434 MHz. 
     Advantageously, the central unit  80  is configured to send the first command signal and the second command signal together within a predetermined time interval, e.g., within a time interval of about 100 milliseconds or about a few hundred milliseconds. 
     In particular, the central unit  80  is configured to send the first command signal and the second command signal together, within a predetermined time interval, e.g., within a predetermined time interval of about 100 milliseconds or about 2-3 hundred milliseconds. 
     Additionally, preferably, the central unit  80  is configured to send a plurality of first command signals equal to one another and spaced apart temporally by a first time interval shorter than the predetermined time interval. Furthermore, preferably together with said plurality of mutually equal first command signals, the central unit  80  is configured to send a plurality of second mutually equal command signals spaced apart temporally by a second time interval shorter than the predetermined time interval and greater than the first predetermined time interval. 
     This allows the same motor activation command to be sent in a redundant manner and on two separate wireless communication channels, minimizing the risk of losing communication. 
     Additionally, this ensures the synchronization between the thrust elements. Indeed, it is substantially ensured that the command is transmitted within the predetermined time interval (in the worst case) and any interference issues are also minimized. 
     In particular, according to an embodiment, the central unit  80  comprises two radio modules at different frequencies, and also each slave board ( 90 A and  90 B) comprises two radio modules at different frequencies. 
     Preferably, a first radio module of said two radio modules is a Bluetooth BLE v5 2.4 GHz communication module. 
     Preferably, the second radio module of said two radio modules is an FSK modulation module with frequency 868 MHz (or in any case a SUB-GHz radio module, i.e., with a carrier less than 1 GHz). 
     Preferably, communications between central unit  80  and slave boards are always transmitted and received in parallel on the two radio modules. 
     In particular, when it wants to perform a movement, the central unit  80  communicates simultaneously with the slave boards ( 90 A and  90 B). In addition to the machine information, the transmitted command signals (first command signal and second command signal) preferably contain synchronization and anti-overlapping control information, such as one or more of the following: package number, command time for executing the command. In particular, the command time for executing the command is a predetermined time value within which the movement command must be executed. For example, the command time is a value of a counter, which is decremented (counted down) and at the end of which the command towards the motors is executed by each slave board ( 90 A,  90 B). In this manner, it is ensured that all motors are activated simultaneously when the predetermined time value expires. 
     In other words, synchrony between the motors is guaranteed. 
     For example, the first and second command signals are transmitted from the central unit  80  repeatedly throughout the predetermined time interval, e.g., for 100 or 200 milliseconds. Transmission occurs both in Bluetooth and with the SUB-GHz radio module, with the particularity that in Bluetooth transmission occurs more frequently (shorter time interval between command signals) and thus a greater quantity of commands is sent within the predetermined time interval, while in SUB-GHz transmission is less frequent and the number of command signals is thus lower within the predetermined time interval. 
     This allows for real-time synchronization of mechanical finger movements. With motion synchronization lags of a few milliseconds. 
     Furthermore, the 868 MHz communication continues to work should there be particular radio disturbances that obscure one of the two carriers, such as Bluetooth. 
     In the same manner, the central unit  80  receives from the slave boards the status and diagnostic information of the latter, e.g., the status of the motors (OK, fault, not connected, short-circuit or mechanical block of the motor) and information of motor driver overtemperatures. 
     Furthermore, the central unit  80  is always aware of the status and quality of wireless communication to and from the slave boards. 
     According to another aspect of the present invention, the last stage  343 A,  343 B of the fork  34 A,  34 B further comprises secondary electrical power supply means  100 A,  100 B (see  FIGS.  7  and  9   ). The secondary electrical power supply means  100 A,  100 B preferably comprise super-capacitors (as shown in particular in  FIG.  9   ). 
     The secondary electrical power supply means  100 A,  100 B power the slave unit  90 A,  90 B, the motor boards  60 A,  61 A,  62 A,  60 B,  61 B,  62 B and the motor means  54 A,  55 A,  56 A,  54 B,  55 B,  56 B. 
     Therefore, advantageously, the slave unit  90 A,  90 B, the motor boards  60 A,  61 A,  62 A,  60 B,  61 B,  62 B, and the motor means  54 A,  55 A,  56 A,  54 B,  55 B,  56 B are independently powered by the secondary electrical power supply means  100 A,  100 B. Furthermore, by virtue of the wireless communication between the slave unit  90 A,  90 B and the central unit  80 , there is no need for cables and related wiring between the last movable stage  343 A,  343 B of the fork  34 A,  34 B, and the parts integral with the frame  21  of the device  20 . The disadvantages associated with the use of cables of known types of systems are thus overcome. 
     In a further aspect of the present invention, a sensor  120 A,  121 A,  122 A,  120 B,  121 B,  122 B is positioned at each finger  50 A,  51 A,  52 A,  50 B,  51 B,  52 B (one of these sensors  120 B being shown in  FIG.  12   ), e.g., an optical and/or magnetic and/or mechanical detector, suitable to detect the position of the finger  50 A,  51 A,  52 A,  50 B,  51 B,  52 B, in particular its vertical retracted position. 
     The finger position  50 A,  51 A,  52 A,  50 B,  51 B,  52 B detected by the corresponding sensor  120 A,  121 A,  122 A,  120 B,  121 B,  122 B is communicated to the slave unit  90 A,  90 B. 
     In a preferred embodiment, the sensors  120 A,  121 A,  122 A,  120 B,  121 B,  122 B are connected to the slave unit  90 A,  90 B through cables. 
     In a preferred embodiment, the sensors  120 A,  121 A,  122 A,  120 B,  121 B,  122 B are connected to the slave unit  90 A,  90 B through wireless communication. 
     Preferably, all of the above-described elements are fitted on the outer side of the last movable stage  343 A,  343 B of the respective fork  34 A,  34 B. In particular, as clearly and unequivocally apparent to the person skilled in the art from the accompanying figures, the motor control unit  90 A,  90 B (or peripheral unit or slave unit) is fitted on the outer side of the last movable stage. Furthermore, the third moving means  54 A,  55 A,  56 A,  54 B,  55 B,  56 B are fitted on the outer side. In particular, the motor of each finger  50 A,  51 A,  52 A,  50 B,  51 B,  52 B, and the respective motor board  60 A,  61 A,  62 A,  60 B,  61 B,  62 B, are all located on the outer side of the last movable stage  343 A,  343 B. Additionally, the secondary electrical power supply means  100 A,  100 B are preferably located on the outer side of the last movable stage. Therefore, this applies to both forks  34 A,  34 B. 
     The arrangement on the outer side of one or more of the aforesaid components, as well as of all of them, makes it advantageously possible to avoid cluttering the inner space, i.e., the resting zone. Therefore, this ensures a suitable space for receiving the boxes in the resting zone  22 , free from other devices. At the same time, this allows the forks  34 A,  34 B to be moved in both directions along the second direction Y, thereby enabling two rows  12 A,  12 B of the warehouse  10  to be served efficiently. Indeed, the presence of an element facing towards the inner side, i.e., towards the resting zone  22 , would be an impediment during the step of translation of the forks in both sides along the second direction Y. 
     It is also apparent that an outer side of the last movable stage means an outer side of the last movable stage arranged on the side opposite to the resting zone  22  for temporarily resting the item S. In other words, each last movable stage  343 A,  343 B of the respective fork  34 A,  34 B comprises a fork inner side facing the resting zone  22 , e.g., when the forks are in a retracted position, and an opposite fork outer side not facing the resting zone  22 . 
     In the presented embodiment, the last movable stage  343 A,  343 B is planar or plate-shaped, preferably the outer fork side and the outer fork side are two opposing sides of the planar or plate-shaped part having greater surface extension. 
     In particular, each of said sensors  120 A,  121 A,  122 A,  120 B,  121 B,  122 B is installed near a corresponding finger  50 A,  51 A,  52 A,  50 B,  51 B,  52 B. 
     According to a further aspect of the present invention, the device  20  comprises electrical interconnection means  150 A,  150 B (see  FIG.  12   ) between the primary electrical power supply means  28  and the secondary electrical power supply means  100 A,  100 B (see  FIG.  7   ). 
     Preferably, the interconnecting means  150 A,  150 B allow the electrical connection between the main electrical power supply means  28  and the secondary electrical power supply means  100 A,  100 B when the fork  34 A,  34 B is in a predetermined position relative to the frame  21 , or recharging position. 
     Preferably, the recharging position corresponds to the retracted position of the fork  34 A,  34 B, i.e., with the last movable stage  343 A,  343 B of the forks  34 A,  34 B at the resting zone  22 . 
     In the recharging position, the secondary electrical power supply means  100 A,  100 B are subjected to recharging the energy from the primary electrical power supply means  28 . 
     According to the illustrated preferred embodiment, the interconnection means  150 A,  150 B comprise two sliding contacts  152 A,  154 A,  152 B,  154 B (see  FIGS.  11  and  12   ), a first contact  152 A,  152 B being associated with the frame  21 , more preferably a first contact  152 A,  152 B associated with the supporting structure  33 A,  33 B of the fork  34 A,  34 B, and a second contact  154 A,  154 B associated with the last movable stage  343 A,  343 B of the fork  34 A,  34 B, as seen in greater detail in  FIG.  8   . 
     The first contact  152 A,  152 B preferably comprises elastic thrust means  156 A,  156 B (see  FIGS.  11  and  12   ) suitable to generate a force towards the fork  34 A,  34 B to guarantee the electrical contact when it contacts the second contact  154 A,  154 B. Furthermore, the second contact  154 A,  154 B preferably comprises inclined surfaces  158 A,  158 B suitable to promote the interaction with corresponding inclined surfaces (not visible) present on the first contact. 
     Therefore, the secondary electrical power supply means  100 A,  100 B are advantageously recharged without needing cables, thus obtaining the above-mentioned advantages resulting from the elimination of the wiring provided in the known type systems. 
     Furthermore, the elimination of wiring simplifies device construction operations compared to known type devices with associated benefits in terms of assembly time and/or costs. 
     Again, advantageously, the reduction of wired parts makes it possible to increase the reliability against known type devices. 
     Furthermore, the removal of wired parts, together with the simultaneous possibility of providing a suitable space for accommodating the boxes, improves the box moving reliability and efficiency. Indeed, by virtue of the absence of other electronic devices on the forks that could clutter or hinder the resting zone, it is possible to avoid undesired collisions, but above all, it is possible to move the forks on both sides of the device to serve opposite rows of the warehouse. 
     A block chart relating to an embodiment variant of the invention is shown with reference to  FIG.  14   , which differs from the prior embodiment in that the central control unit  80 ′ further comprises a second unit  800 ′, or master unit, which is interposed between the communication stream to or from the slave unit(s)  90 A,  90 B. 
     The function of the master unit  800 ′ is to send command signals for operating the motor means  54 A,  55 A,  56 A,  54 B,  55 B,  56 B and to collect signals from the sensors  120 A,  121 A,  122 A,  120 B,  121 B,  122 B which control the position of the fingers  50 A,  51 A,  52 A,  50 B,  51 B,  52 B. The signals from the sensors  120 A,  121 A,  122 A,  120 B,  121 B,  122 B are detected by the slave units and then sent to the master unit  800 ′ which sends the status of the sensors to the central unit  80 ′. 
     The communication between the master unit  800 ′ and the slave unit(s)  90 A,  90 B is preferably a wireless communication. 
     The communication between the master unit  800 ′ and the central control unit  80 ′ is preferably wired. 
     In a variant embodiment, the communication between the master unit  800 ′ and the central control unit  80 ′ is preferably a wireless communication. 
     Finally, it is worth noting that the wireless type communications mentioned in this description are preferably compliant with the Bluetooth Low Energy or BLE 4.2 standard. 
     Therefore, this description has demonstrated that the device according to the present invention achieves the predetermined objects. In particular, the device according to the present invention makes it possible to reduce the construction complexity with respect to the devices of the known type. 
     Although the present invention is explained above by means of a detailed description of embodiments thereof shown in the drawings, the present invention is not obviously limited to the embodiments described above and shown on the drawings; on the contrary, further variants of the described embodiments fall within the object of the present invention as defined by the claims.