Conveying device

Abstract

To provide a conveying device that can suppress positional deviation of a shelf relative to a lifter, for example, when decelerating or stopping during conveyance of the shelf.SOLUTION: According to an embodiment, a conveying device includes a conveying vehicle that moves within a predetermined range, a lifter, an electromagnet, and batteries. The lifter is provided on the upper part of the conveying vehicle in a vertically movable manner relative to the conveying vehicle. The lifter moves between an ascended position where the lifter lifts up a shelf on which one or more articles are placed, and a descended position where the lifter lowers the shelf and places it on the floor surface. The electromagnet is provided on the lifter, and when electric current is supplied, the electromagnet is attached to the bottom surface of the shelf by magnetic force, and when the electric current supply is stopped, the magnetic force on the bottom surface is gone. The battery supplies electric power to the conveying vehicle, the lifter, and the electromagnet.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] Embodiments of the present invention relate to a conveying device.

Background Art

[0002] In a logistics warehouse or the like, for example, articles are placed on shelves respectively, and the shelves are conveyed to various station positions and the like simultaneously and in parallel using a conveying device selected from a number of conveying devices such as AGVs (Automatic Guided Vehicles). For example, when conveying a shelf with a conveying device, the shelf is conveyed in a state where it is placed on a lifter of the conveying device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide a conveying device capable of suppressing the positional deviation of a shelf with respect to a lifter, for example, during deceleration or stop while the shelf is being conveyed.

Means for Solving the Problems

[0005] According to an embodiment, the conveying device includes a carrier that moves within a predetermined range, a lifter, an electromagnet, and a battery. The lifter is provided above the carrier so as to be movable up and down with respect to the carrier. The lifter moves between a raised position where it lifts a shelf on which one or more articles are placed and a lowered position where it lowers the shelf and places it on the floor surface. The electromagnet is provided on the lifter, and when current is supplied, it adheres to the bottom surface of the shelf by magnetic force, and when the supply of current is stopped, the magnetic force with respect to the bottom surface of the shelf is released. The battery supplies power to the carrier, the lifter, and the electromagnet.

Brief Description of the Drawings

[0006]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

[0007] The article conveying system 100 according to the embodiment will be described with reference to FIGS. 1 to 9.

[0008] FIG. 1 is a block diagram showing an example of a system configuration including the article conveying system 100 and a host server (host system) 1 according to the present embodiment.

[0009] As shown in FIG. 1, the article conveying system 100 includes a control device 2, a conveyor controller 4, and a conveyor 7. Note that the article conveying system 100 preferably includes a picking robot that picks up articles and places them in a shelf (mobile shelf) 8 and its controller, etc., but the description thereof is omitted here.

[0010] The upper server 1 is referred to as a warehouse management system (WMS: Warehouse Management System) and can be realized by one or more computers. The upper server 1 stores article identification information, order information, etc. regarding articles. The article identification information indicates the articles stored in each shelf 8. The order information indicates a picking operation for picking up articles from each shelf 8. The upper server 1 transmits the article identification information and the order information to the control device 2.

[0011] The control device 2 transmits control information for picking operations and the like to the conveyor controller 4 and a robot controller (not shown). Further, the control device 2 controls a charger 5 that charges the battery of the conveyor 7.

[0012] The control device 2 will be described. FIG. 2 is a block diagram showing an example of the configuration of the control device 2 according to the embodiment. The control device 2 includes a processor 21 (control unit), a ROM 22, a RAM 23, an NVM 24 (non-volatile memory / storage unit), and a communication interface 25 (communication unit).

[0013] The processor 21, the ROM 22, the RAM 23, the NVM 24, and the communication interface 25 are connected to each other via a data bus or the like. Note that the control device 2 may have a configuration as required in addition to the configuration shown in FIG. 2, or a specific configuration may be excluded from the control device 2.

[0014] The processor 21 corresponds to the central part of a computer that performs processes such as operations and controls necessary for the processing of the control device 2, and integrally controls the entire control device 2. The processor 21 executes control to realize various functions of the control device 2 based on programs such as system software, application software, or firmware stored in the ROM 22 or the NVM 24. The processor 21 is, for example, a CPU (Central Processing Unit), an MPU (Micro Processing Unit), or a DSP (Digital Signal Processor). Alternatively, the processor 21 is a combination of a plurality of these.

[0015] The ROM 22 corresponds to the main storage device of a computer centered on the processor 21. The ROM 22 is a non-volatile memory exclusively used for reading data. The ROM 22 stores the above programs. The ROM 22 also stores data used by the processor 21 for performing various processes or various setting values.

[0016] The RAM 23 corresponds to the main storage device of a computer centered on the processor 21. The RAM 23 is a memory used for reading and writing data. The RAM 23 is used as a so-called work area that stores data temporarily used by the processor 21 when performing various processes.

[0017] The NVM 24 (Non-volatile memory) corresponds to the auxiliary storage device of a computer centered on the processor 21. The NVM 24 is, for example, an EEPROM (Electric Erasable Programmable Read-Only Memory) (registered trademark), an HDD (Hard Disk Drive), or an SSD (Solid State Drive). The NVM 24 may store the above programs. The NVM 24 also stores data used by the processor 21 for performing various processes, data generated by the processing in the processor 21, or various setting values.

[0018] The transfer device controller 4, which is called a warehouse control system (WCS), controls at least one transfer device 7. For example, the transfer device controller 4 acquires the travel route of the transfer device 7 from the control device 2. Based on the travel route of the transfer device 7 acquired from the control device 2, the transfer device controller 4 transmits a transfer control signal for performing transfer to the transfer device 7. Further, the transfer device controller 4 receives a signal indicating that the transfer has been completed from the transfer device 7, and transmits a signal indicating that the transfer of the article related to the order information acquired from the control device 2 has been completed to the control device 2.

[0019] FIG. 3 and FIG. 4 show the transfer device 7 according to the present embodiment and a shelf (transfer shelf) 8 on which one or a plurality of articles to be transferred by the transfer device 7 are placed.

[0020] Here, an XYZ orthogonal coordinate system is set for the transfer device 7 and the shelf 8 shown in FIGS. 3 and 4. It is assumed that the X-axis direction is the extending direction of the shelf board 8b of the shelf 8. It is assumed that the Y-axis direction is the depth direction of the shelf board 8b of the shelf 8. It is assumed that the Z-axis direction is the height direction of the shelf 8. The height of the shelf 8 is defined, for example, by the height of the ceiling in the warehouse with respect to the floor surface F.

[0021] As shown in FIGS. 3 and 4, the shelf 8 includes legs 8a placed on a floor surface (for example, a horizontal plane horizontal to the XY plane) F and a plurality of shelf boards 8b spaced apart vertically, for example.

[0022] In the present embodiment, among the plurality of shelf boards 8b, the lower surface of the lowermost shelf board 8b is provided as a shelf bottom surface 8c. Although not shown, the shelf 8 may include a shelf bottom plate having the shelf bottom surface 8c separately from the shelf board 8b.

[0023] The shelf bottom surface 8c is preferably formed as a horizontal plane with respect to the floor surface F, but may not be a horizontal plane, for example, a surface formed to fit with the upper surface 42c of the lifting plate 42b of a lifter 42 described later of the transfer device 7.

[0024] In this embodiment, it is preferable that the bottom surface 8c of the shelf 8 is formed of a ferromagnetic material that adheres to a magnet, preferably a soft magnetic material such as iron. Alternatively, a soft magnetic material, preferably a soft magnetic material such as an iron plate, is fixed to the bottom surface 8c of the shelf 8. In the latter case, it is preferable that the bottom surface 8c itself is formed of a material that is not a ferromagnetic material.

[0025] In addition, in order to prevent the articles placed on the shelf 8 from being affected by the magnetic force of the electromagnetic magnet 43 described later, the shelf board 8b may be made of a material having, for example, magnetic shielding properties.

[0026] Further, a code 9 such as a QR code (registered trademark) is fixed to the center of the bottom surface 8c of the shelf 8 in the width direction (X-axis direction) and near the center in the depth direction (Y-axis direction) in FIG. 3. The code 9 is provided directly below the centroid of the lowermost shelf board 8b of the shelf 8. This code 9 is for identifying the shelf 8 by being read by a code reader 44 of the conveying device 7 described later, and it is preferable that all are identified as different shelves 8 in one logistics warehouse.

[0027] FIGS. 5 and 6 show schematic views of the conveying device 7. FIG. 5 shows a state where the lifter 42 is lowered with respect to the transport vehicle 41, and FIG. 6 shows a state where the lifter 42 is raised with respect to the transport vehicle 41. FIG. 7 shows a top view of the lifter 42, the electromagnetic magnet 43, and the code reader 44 of the conveying device 7 as viewed from the direction indicated by the arrow V in FIG. 5.

[0028] As shown in FIGS. 5 to 7, the conveying device 7 includes a transport vehicle 41, a lifter 42, an electromagnetic magnet 43, and a code reader 44.

[0029] The transport vehicle 41 is placed on the floor surface F and is movable within a predetermined range. The weight of the transport vehicle 41 is, for example, about 200 kg. Further, the maximum load capacity of the transport vehicle 41 can be set as appropriate, but it is preferably, for example, about 100 kg or more and preferably about several tons or less.

[0030] The lifter 42 is provided on the upper part of the carrier 41. The lifter 42 is capable of ascending and descending with respect to the upper surface (upper part) of the carrier 41, and can lift the shelf 8 from the floor surface F or lower it to the floor surface F. The lifter 42 moves between a raised position where it lifts the shelf 8 and a lowered position where it lowers the shelf 8 and places it on the floor surface F by ascending and descending with respect to the upper part of the carrier 41.

[0031] The lifter 42 includes a lifting rod 42a that ascends and descends relative to the carrier 41, and a lifting plate 42b that is supported by the lifting rod 42a and has an upper surface 42c that comes into contact with and separates from the bottom surface 8c of the shelf board 8b of the shelf 8 by ascending and descending. The upper surface 42c of the lifting plate 42b only needs to be able to support at at least three points that are separated from each other when lifting the shelf 8. However, in this embodiment, it is preferably formed to have an annular portion 42d as shown in FIG. 7, for example. The inside of the annular portion 42d may be formed as a circular cavity, for example, and a transparent plate material such as an acrylic plate may be provided.

[0032] In addition, when the lifter 42 is in the lowered position shown in FIGS. 3 and 5, the upper surface 42c of the lifter 42 of the conveying device 7 can be arranged below the bottom surface 8c of the shelf board 8b of the shelf 8. For this reason, the conveying device 7 can enter and exit below the bottom surface 8c of the shelf board 8b of the shelf 8.

[0033] Also, when the lifter 42 is in the raised position shown in FIGS. 4 and 5, the upper surface 42c of the lifter 42 of the conveying device 7 can push up the bottom surface 8c of the shelf board 8b of the shelf 8 upward and separate the leg portion 8a of the shelf 8 from the floor surface F upward. For this reason, the conveying device 7 can lift the shelf 8. And the conveying device 7 can travel in a state where the shelf 8 is lifted.

[0034] The electromagnet 43 is provided, for example, on the lifting plate 42b of the lifter 42. It is preferable that a plurality of the electromagnets 43 are arranged at intervals in, for example, the annular portion 42d of the lifter 42. For example, when a current flows through the wiring 43a from the battery 52, the electromagnet 43 generates a magnetic force, and when the flow of the current stops, the magnetic force disappears. In the present embodiment, when the current is supplied, the electromagnet 43 exhibits a magnetic force that attempts to adhere to the bottom surface 8c of the shelf 8, and when the supply of the current stops, the magnetic force is released.

[0035] If the electromagnet 43 is fixed to the lower surface of the lifting plate 42b, it is preferable that the lifting plate 42b is formed of a ferromagnetic material or a material having permeability.

[0036] Note that the magnetic force of the electromagnet 43 changes depending on the magnitude of the current flowing through the electromagnet 43. Therefore, it is preferable that the magnitude of the current flowing through the electromagnet 43 can be adjusted within a predetermined range. Suppose the conveying device 7 with the lifter 42 in the lowered position is arranged directly below the bottom surface 8c of the shelf board 8b of the shelf 8. Even when the magnetic force by the electromagnet 43 is made the strongest in this state, the magnetic force of the electromagnet 43 is adjusted so that the conveying device 7 does not float toward the shelf board 8b.

[0037] On the other hand, suppose the conveying device 7 with the lifter 42 in the raised position is lifting the shelf 8. When the conveying vehicle 41 suddenly stops while the shelf 8 is being conveyed at an appropriate speed in this state, a moment is applied to the shelf 8, but also at this time, the magnetic force of the electromagnet 43 is adjusted so that the shelf 8 hardly deviates from the lifter 42. Note that the weight or weight balance of the conveying device 7 is set so that the conveying vehicle 41 remains in that position without tipping over the shelf 8 and the conveying device 7 even when a moment is applied to the shelf 8. Hardly deviating means that a displacement to such an extent that the position where the code 9 can be read by the code reader 44 is maintained is allowed. If the maximum speed when the shelf 8 is being conveyed by the conveying device 7 is a predetermined speed, such a magnetic force is adjusted, for example, according to the weight of the article transmitted from the upper server 1 or the like.

[0038] The code reader 44 is provided on the carrier 41 or the lifter 42. The code reader 44 can read the code 9 provided on the shelf 8 through the annular portion 42d.

[0039] Preferably, the optical axis of the code reader 44 coincides with the central axis of the annular portion 42d. Further, preferably, the optical axis of the code reader 44 coincides with the center in the width direction along the X-axis direction of the lifting plate 42b and the center in the depth direction along the Y-axis direction. The conveying device 7 lifts and lowers the lifter 42 while maintaining the state where the code reader 44 can read the code 9 on the shelf board 8b of the shelf 8, thereby stably lifting and lowering the shelf 8.

[0040] Further, FIG. 8 shows a schematic block diagram of the conveying device 7.

[0041] As shown in FIG. 8, the conveying device 7 further includes a control unit (processor) 51, a battery (storage battery) 52, a carrier driving unit 53, a lifter driving unit 54, and a sensor 55.

[0042] The control unit 51 includes, for example, a processor, a communication interface, a ROM, a RAM, etc., similar to the control device 2.

[0043] The control unit 51 can control the electromagnet 43, the code reader 44, the battery 52, the carrier driving unit 53, the lifter driving unit 54, and various sensors 55.

[0044] In the present embodiment, the control unit 51 can control the ON / OFF of the current flowing through the electromagnet 43 and can adjust the magnitude of the current flowing through the electromagnet 43. The control unit 51 can increase the magnitude of the current as the weight of the article placed on the shelf 8 increases.

[0045] The control unit 51 controls the code reader 44 to read the code 9 provided on the shelf 8, and can determine whether it matches the shelf 8 according to the command from the upper server 1.

[0046] The battery 52 supplies the necessary power to the electromagnet 43, the code reader 44, the control unit (processor) 51, the carrier vehicle drive unit 53, the lifter drive unit 54, and various sensors 55, respectively. The power supplied to the electromagnet 43, the code reader 44, the carrier vehicle drive unit 53, the lifter drive unit 54, and various sensors 55 is adjusted by the control unit 51. Note that the battery 52 of the transport device 7 is charged by a charger 5 controlled by the control device 2.

[0047] The carrier vehicle drive unit 53 is, for example, a combination of a motor and gears, and is provided on the carrier vehicle 41 shown in FIG. 3 to move the carrier vehicle 41 within a predetermined range. The traveling speed of the carrier vehicle 41 is adjusted by the control of the carrier vehicle drive unit 53 by the control unit 51. The traveling speed of the carrier vehicle 41 can be appropriately set, for example, when the transport device 7 travels while lifting the shelf 8, that is, when the transport device 7 is transporting the shelf 8, and when it travels without transporting the shelf 8 and without the shelf 8. As an example, the traveling speed of the carrier vehicle 41, that is, the speed of the transport device 7, is preferably about 2.5 m / s at maximum. For example, when the transport device 7 is transporting the shelf 8, the traveling speed of the carrier vehicle 41 is preferably about 1.0 m / s as an example, and when it is not transporting the shelf 8, it is preferably about 1.5 m / s as an example.

[0048] The lifter drive unit 54 is, for example, a combination of a motor and gears, and is provided on the carrier vehicle 41 to raise and lower the lifter 42 within a predetermined range. The lifter drive unit 54 can bring the upper surface 42c of the lifter 42 into contact with the bottom surface 8c of the shelf 8 to lift the shelf 8. Note that the time for raising the lifter 42 from the above-described lowered position to the raised position is preferably a predetermined time. Also, the time for lowering the lifter 42 from the raised position to the lowered position is preferably a predetermined time. Note that the predetermined time for raising the lifter 42 and the predetermined time for lowering it may be the same or different.

[0049] The various sensors 55 are used, for example, for guiding the carrier vehicle 41. When the carrier vehicle 41 is, for example, path-guided, the sensor 55 reads the code or marker on the floor surface F by, for example, image recognition or the like. When the carrier vehicle 41 is, for example, self-propelled, the sensor 55 can use LiDAR or the like.

[0050] In addition, the sensor 55 is used for detecting obstacles. For example, when an article is on the path of the conveying device 7, the control unit 51 stops the carrier vehicle 41 based on the detection result of the sensor 55.

[0051] Hereinafter, an example of the conveyance process of the shelf 8 using the conveyance device 7 will be described using the flow of FIG. 9.

[0052] Based on a command from the upper server 1, the conveyance device controller 4 moves the designated conveyance device 7 under the designated shelf 8 (step S1). At this time, the control unit 51 of the conveyance device 7 reads the code under the shelf 8 using the code reader 44. The control unit 51 of the conveyance device 7 transmits and receives signals to and from the upper server 1 to confirm that it is the shelf 8 to be conveyed.

[0053] Then, while maintaining the state where the code 9 of the shelf 8 and the code reader 44 of the conveyance device 7 face each other, the control unit 51 of the conveyance device 7 controls the lifter drive unit 54 of the lifter 42 and lifts the shelf 8 with the lifter 42 (step S2). For this reason, the lifter 42 separates the leg portion 8a of the shelf 8 from the floor surface F upward.

[0054] When a predetermined time has elapsed since the control unit 51 of the conveyance device 7 starts driving the lifter drive unit 54, the control unit 51 determines that the shelf 8 has been completely lifted (step S3). That is, the control unit 51 of the conveyance device 7 controls the carrier vehicle drive unit 53 and maintains the positional relationship between the carrier vehicle 41 and the floor surface F until a predetermined time has elapsed since the lifter drive unit 54 started driving.

[0055] Alternatively, the control unit 51 of the transport device 7 controls the rotation angle of the motor of the lifter drive unit 54, and determines that the shelf 8 has been completely lifted when the rotation angle of the motor of the lifter drive unit 54 reaches a predetermined rotation angle from the rotation angle of the reference position.

[0056] Note that, for example, when the rotation angle of the motor per unit time is controlled to be constant, the time from the reference rotation angle to the predetermined rotation angle of the rotation angle of the motor of the lifter drive unit 54 can be calculated. Therefore, the control unit 51 of the transport device 7 can lift the shelf 8 to a predetermined height by the lifter 42 by driving the motor of the lifter drive unit 54 for that time.

[0057] After a predetermined time has elapsed since starting to drive the lifter drive unit 54, when the control unit 51 of the transport device 7 recognizes that the code 9 read by the code reader 44 is correct, it passes an electric current from the battery 52 to the electromagnet 43. Therefore, the control unit 51 of the transport device 7 passes an electric current through the electromagnet 43 and attaches the bottom surface 8c of the shelf 8 to the electromagnet 43 by the magnetic force of the electromagnet 43 (step S4). Thereafter, the control unit 51 of the transport device 7 continues to pass an electric current through the electromagnet 43 until reaching step S10 described later.

[0058] The total weight of the articles placed on the shelf 8 is calculated by the upper server 1. Therefore, the control unit 51 of the transport device 7 adjusts, for example, the magnitude of the current supplied from the battery 52 according to the total weight of the articles. Therefore, the adsorption force (magnetic adsorption force) due to the magnetic force between the electromagnet 43 and the bottom surface 8c of the shelf 8 is adjusted according to the total weight of the articles placed on the shelf 8.

[0059] The control unit 51 of the transport device 7 controls the transport vehicle drive unit 53 and transports the shelf 8 to the destination (step S5).

[0060] When transporting the shelf 8 toward the destination, the control unit 51 of the transport device 7 determines whether intermediate work is necessary (step S6).

[0061] When intermediate work is required (S6-Yes), perform the intermediate work (step S7). The intermediate work here is, for example, taking out one or more of the articles placed on the shelf 8 at a certain station. At this time, the control unit 51 of the transfer device 7 maintains the state in which the shelf 8 is lifted.

[0062] After performing the intermediate work, the control unit 51 of the transfer device 7 moves the shelf 8 to the position where it is lowered while maintaining the state in which the shelf 8 is lifted (step S8).

[0063] When the intermediate work is not required (S6-No) or following the work in step S8, the control unit 51 of the transfer device 7 causes the transfer device 7 to arrive at the position where the shelf 8 is lowered and confirms the actual arrival (step S9).

[0064] The control unit 51 of the transfer device 7 controls the transfer vehicle drive unit 53 to maintain the positional relationship between the transfer vehicle 41 and the floor surface F. Then, the control unit 51 of the transfer device 7 turns off the current of the electromagnet 43 to release the adsorption by the magnetic force between the electromagnet 43 and the bottom surface 8c of the shelf 8 (step S10).

[0065] The control unit 51 of the transfer device 7 controls the lifter drive unit 54 to lower the legs 8a of the shelf 8 to the floor surface F (step S11). At this time, the control unit 51 of the transfer device 7 further lowers the lifter 42 to release the contact between the lifter 42 and the bottom surface 8c of the shelf 8.

[0066] When a predetermined time has elapsed since the control unit 51 of the transfer device 7 starts driving the lifter drive unit 54, it determines that the legs 8a of the shelf 8 have been completely lowered to the floor surface F and furthermore, the contact between the lifter 42 and the bottom surface 8c of the shelf 8 has been released. The control unit 51 of the transfer device 7 controls the transfer vehicle drive unit 53 to maintain the positional relationship between the transfer vehicle 41 and the floor surface F until a predetermined time has elapsed since the control unit 51 starts driving the lifter drive unit 54.

[0067] Alternatively, the control unit 51 of the transfer device 7 controls the rotation angle of the motor of the lifter drive unit 54, and when the rotation angle of the motor of the lifter drive unit 54 returns from the rotation angle at the position where the shelf 8 has been lifted completely to the rotation angle of the reference position, the leg portion 8a of the shelf 8 is completely lowered to the floor surface F, and further, it is determined that the contact between the lifter 42 and the bottom surface 8c of the shelf 8 has been released.

[0068] In addition, for example, when the rotation angle of the motor per unit time is controlled to be constant, since the time from the reference rotation angle to a predetermined rotation angle can be calculated, the control unit 51 of the transfer device 7 drives the lifter drive unit (motor) 54 for that time, so that the shelf 8 can be lowered from a predetermined height by the lifter 42 until the leg portion 8a of the shelf 8 is completely lowered to the floor surface F, and further, the contact between the lifter 42 and the bottom surface 8c of the shelf 8 can be released.

[0069] Then, the control unit 51 of the transfer device 7 moves the transfer device 7 from below the shelf 8 to a new destination so that the transfer device 7 does not contact the shelf 8 (step S12). The new destination is, for example, below the charger 5 or below the bottom surface 8c of another shelf 8 different from the transported shelf 8.

[0070] For example, before the transport vehicle 41 transporting the shelf 8 arrives at the destination, it may decelerate or stop due to the influence of an obstacle detected by the sensor 55 or the like. In such a case, since the electromagnet 43 provided on the lifter 42 and the bottom surface 8c of the shelf 8 are attracted to each other by magnetic force, the bottom surface 8c is prevented from being displaced with respect to the lifter 42 of the transfer device 7. That is, for example, the state where the cord 9 of the bottom surface 8c and the cord reader 44 of the transfer device 7 face each other is maintained. Therefore, by using the transfer device 7 according to the present embodiment, it is possible to prevent the transfer device 7 from being unable to recognize the shelf 8 and getting stuck in the logistics warehouse, and to reliably transport the shelf 8 to the destination. Therefore, by using the transfer device 7 according to the present embodiment, it is possible to suppress the possibility of having a great impact on the system in the logistics warehouse.

[0071] Generally, if the position deviation of the shelf 8 from the transfer device 7 exceeds a predetermined value and the transfer device 7 can no longer recognize the shelf 8, the transfer device 7 in the state of lifting the shelf 8 may get stuck. In this case, it may affect the movement of other transfer devices 7 that are scheduled to pass through the route of the transfer device 7.

[0072] However, by using the transfer device 7 according to the present embodiment, even if the transfer device 7 decelerates or stops at a position that is not the destination, the positional relationship with the shelf 8 can be maintained. Therefore, according to the present embodiment, it is possible to provide a transfer device 7 that can suppress the positional deviation of the shelf 8 with respect to the lifter 42, for example, during deceleration or stop while the shelf 8 is being transported. And by using the transfer device 7 according to the present embodiment, the shelf 8 can be surely transported to the destination. For this reason, by using the transfer device 7 according to the present embodiment, it is possible to suppress the possibility of having a great impact on the system in the logistics warehouse.

[0073] According to the transfer device 7 according to the present embodiment, it is possible to suppress the possibility that the shelf causes a positional deviation with respect to the transfer device 7 when the transfer device 7 stops or decelerates. For this reason, it is possible to prevent the transfer device 7 that has lifted the misaligned shelf 8 from remaining stopped in the logistics warehouse. Therefore, by using the transfer device 7 according to the present embodiment, it is possible to suppress the possibility of having a great impact on the system in the logistics warehouse.

[0074] According to the present embodiment, it is preferable that the control unit 51 of the transfer device 7 controls to supply current to the electromagnet 43 after the lifter 42 has placed the shelf 8 in the raised position and before the transfer cart 41 starts to move. For this reason, for example, before the transfer device 7 starts to move, the action of the electromagnet 43 prevents the positional deviation of the shelf 8 with respect to the transfer device 7. Therefore, when the transfer device 7 decelerates or stops after it starts to move, it is possible to prevent the shelf 8 from being positionally deviated with respect to the lifter 42.

[0075] According to this embodiment, when the control unit 51 of the transfer device 7 arranges the lifter 42 at the raised position so that the shelf 8 is lifted and the shelf 8 is being transferred by the movement of the transfer cart 41, or when the movement of the transfer cart 41 stops, the control unit 51 controls the electromagnet 43 to supply a current that generates a magnetic force to prevent the shelf 8 from moving relative to the lifter 42 due to the moment applied to the shelf 8. Therefore, for example, when the transfer device 7 starts to move and then decelerates or stops, it is possible to prevent the shelf 8 from being misaligned with respect to the lifter 42.

[0076] According to this embodiment, when the transfer cart 41 reaches the target position and stops moving with the shelf 8 arranged at the raised position by the lifter 42, it is preferable that the control unit 51 of the transfer device 7 controls to stop the supply of current to the electromagnet 43 before starting to move the lifter 42 from the raised position to the lowered position. Further, according to this embodiment, it is preferable that the control unit 51 of the transfer device 7 controls to lower the shelf 8 with the lifter 42 after stopping the supply of current to the electromagnet 43 and place the shelf 8 on the floor surface F. For this reason, since the magnetic force of the electromagnet 43 has already disappeared before lowering the lifter 42, even when the lifter 42 is lowered and the legs 8a of the shelf 8 are placed on the floor surface F, it is possible to prevent the shelf board 8b from being further pulled downward by the electromagnet 43.

[0077] (Modification example) FIG. 10 illustrates a modification example of the transfer device 7 according to the embodiment.

[0078] As shown in FIG. 10, the electromagnet 43 of the transfer device 7 may be embedded in the lifting plate 42b of the lifter 42. In this case, the lifting plate 42b can be formed of an appropriate plate material.

[0079] In this way, the arrangement position of the electromagnet 43 with respect to the lifter 42 of the transfer device 7 is appropriately set. Also, depending on the arrangement position of the electromagnet 43 with respect to the lifter 42, the lifting plate 42b of the lifter 42 can be formed of an appropriate material.

[0080] Even if the transfer device 7 is configured in this way, it is possible to suppress the positional deviation of the shelf 8 with respect to the lifter 42, for example, during deceleration or stop while the shelf 8 is being transferred.

[0081] According to the transfer device 7 of at least one embodiment described above, it is possible to suppress the positional deviation of the shelf 8 with respect to the lifter 42, for example, during deceleration or stop while the shelf 8 is being transferred.

[0082] Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

Explanation of Reference Numerals

[0083] 1... upper server, 2... control device, 4... transfer device controller, 5... charger, 7... transfer device, 8... shelf (mobile shelf), 8a... leg portion, 8b... shelf board, 8c... bottom surface of shelf, 9... cord, 41... transfer cart, 42... lifter, 42a... lifting rod, 42b... lifting plate, 42c... upper surface, 42d... annular portion, 43... electromagnet, 43a... wiring, 44... cord reader, 51... control unit, 52... battery, 53... transfer cart drive unit, 54... lifter drive unit, 55... sensor, 100... article transfer system.

Claims

1. A carrier that moves within a specified range, a lifter that is provided above the carrier so as to be able to move up and down relative to the carrier, and moves between a raised position where one or more articles are placed on a shelf and a lowered position where the shelf is lowered and placed on the floor surface, an electromagnet provided on the lifter that exerts a magnetic force to adhere to the bottom surface of the shelf when current is supplied, and releases the magnetic force when the supply of the current is stopped, and a battery that supplies power to the carrier, the lifter, and the electromagnet A conveying device having the above components.

2. A plurality of the electromagnets are arranged on the lifter in a separated state, The conveying device according to Claim 1.

3. A code reader provided on the carrier or the lifter and capable of reading a code provided on the bottom surface of the shelf, The electromagnet is arranged so as to surround the code reader, The conveying device according to Claim 1 or Claim 2.

4. A control unit that receives power supply from the battery and controls the carrier, the lifter, the electromagnet, and the battery, The control unit controls to supply the current to the electromagnet after the lifter has lifted the shelf and placed it in the raised position and before the carrier starts to move. The conveying device according to Claim 1 or Claim 2.

5. A control unit that receives power supply from the battery and controls the carrier, the lifter, the electromagnet, and the battery, The control unit controls to stop the supply of the current to the electromagnet after the carrier has reached the target position with the shelf placed in the raised position by the lifter, the movement of the carrier has been stopped, and before the lifter starts to move from the raised position toward the lowered position. The conveying device according to Claim 1 or Claim 2.

6. The control unit controls to lower the shelf with the lifter after stopping the supply of the current to the electromagnet, place the lifter in the lowered position, and place the shelf on the floor surface. The conveying device according to Claim 5.

7. A control unit that receives power supply from the battery and controls the carrier, the lifter, the electromagnet, and the battery, When the control unit places the lifter at the raised position so that the shelf is lifted, or when the shelf is being conveyed by the movement of the carrier vehicle, or when the moment applied to the shelf when the movement of the carrier vehicle stops causes the shelf to move relative to the lifter, the control unit controls to supply the current, which becomes a magnetic force for preventing such movement, to the electromagnet. The conveying device according to claim 1 or claim 2.

8. The control unit controls the magnetic force based on the weight of the article placed on the shelf. The conveying device according to claim 7.

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