CN112478650A

CN112478650A - Intelligent automatic loading and unloading vehicle system and method

Info

Publication number: CN112478650A
Application number: CN202011479153.0A
Authority: CN
Inventors: 闵定勇; 邹朝普; 丁兴; 胡恒杰; 徐文东; 张志英; 屈贤德; 沈田田
Original assignee: KSEC Intelligent Technology Co Ltd
Current assignee: KSEC Intelligent Technology Co Ltd
Priority date: 2020-12-14
Filing date: 2020-12-14
Publication date: 2021-03-12

Abstract

The invention discloses an intelligent automatic loading and unloading vehicle system which comprises a platform system, a lifting system, a carriage storage system, a shuttle system and a controller, wherein the platform system, the lifting system, the carriage storage system, the shuttle system and the controller are sequentially connected and arranged, the shuttle system is communicated with the platform system, the lifting system and the carriage storage system, so that materials can be conveyed among the platform system, the lifting system and the storage system through the shuttle system and can be loaded and unloaded, and the shuttle system is connected with the controller. The invention 1 realizes the automatic operation of the material warehouse-out loading and unloading vehicle, reduces the labor intensity of manpower and has high operation efficiency; 2. the track is arranged only on the goods shelf in the carriage, and the power-free mechanism is adopted, so that the structure is simple, and the transformation difficulty is small; 3. adopt multilayer goods shelves, the material is deposited efficiently, can carry out make full use of to the carriage space. 4. The shuttle plate can be configured according to the loading and unloading demand of the materials out of the warehouse, so that the equipment investment is reduced.

Description

Intelligent automatic loading and unloading vehicle system and method

Technical Field

The invention belongs to the technical field of logistics, and particularly relates to an intelligent automatic loading and unloading vehicle system and an intelligent automatic loading and unloading vehicle method.

Background

At present, aiming at the field of logistics transportation, along with the continuous development of production technology, automatic operation is basically realized in each link of logistics transportation, but because the existing production technology is not mature enough, an efficient loading and unloading operation mode is not formed in the link of unloading and loading goods out of a warehouse, so that the transportation efficiency of the whole logistics transportation process of the goods is limited. The traditional goods loading and unloading car operation mode is that manpower and fork truck work in coordination usually, need a large amount of manpower and materials at the loading and unloading car process, and this kind of operation mode manual labor intensity is big to the fork truck loading probably causes the goods to damage, and efficiency is not high, does not reach the level of present commodity circulation high efficiency far away. Therefore, it is an urgent problem to use an intelligent loading and unloading system in the material loading and unloading process to improve the operation efficiency.

Patent CN108455156B discloses an intelligent cargo handling system for unmanned warehouse and a control method thereof. The invention provides an intelligent goods loading and unloading system for an unmanned warehouse, which comprises a goods stacking area, a delivery area, a loading and unloading area and a parking area. This intelligence goods handling system utilizes AGV to carry out goods and materials transport, need set up a large amount of AGV and carry out the operation, and the difficulty is solved to AGV dispatch problem, in addition, if need a large amount of goods and materials warehouse-out, AGV operating efficiency remains to be promoted.

Patent CN207684528U discloses an automatic loading and unloading vehicle system for cartons, paper film bags and woven bags. The automatic loading and unloading vehicle system is used for realizing automatic loading and unloading after the boxing of an industrial explosive production line is finished, and mainly comprises a pushing mechanism, a righting mechanism, a lifting mechanism and a double-layer storage mechanism in a carriage. After the materials are boxed, the materials are conveyed to the pushing mechanism through the conveying belt, the material position is adjusted through the righting mechanism, and the materials are conveyed to the double-layer storage mechanism in the carriage after the height difference between the carriage and the platform is adjusted through the lifting mechanism. The conveying system of the automatic loading and unloading vehicle is composed of conveying belts, wherein a roller type conveying belt is adopted inside a carriage, a storage mechanism is required to be provided with power, the installation difficulty of the storage mechanism inside the carriage is high, the system arrangement difficulty of electric control and the like is high, the manufacturing cost is high, the quality of the conveying belt is high, and the load of the vehicle is greatly increased. Patent CN208516531U discloses an automatic loading and unloading vehicle system for boxcars. The automatic loading and unloading vehicle system comprises a stacking machine to be stacked, an unpowered roller way conveyor, a loading device, a vertical push-pull device and a stacking robot, wherein the stacking machine is in butt joint with a production line. The materials are transported to the stacking machine from the production line, the stacking robot stacks the materials on the plastic sliding support plate on the unpowered roller conveyor, and the whole stack of materials is pushed to the inside of the carriage by the pusher. Inside this automatic handling system utilized the propeller to with material propelling movement to the carriage, the material efficiency of advancing the car is not high, and whole buttress material quality is great, and the smooth tray of plastics is worn and torn easily to this handling system carriage is inside only has the one deck, unable make full use of carriage space.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides an intelligent automatic loading and unloading vehicle system which is beneficial to completing automatic loading and unloading after goods and materials are delivered out of a warehouse, improves the loading and unloading vehicle efficiency, reduces the waste of manpower and material resources, and solves the defects in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:

the intelligent automatic loading and unloading vehicle system is characterized by further comprising a shuttle system, wherein the shuttle system is communicated with the platform system, the lifting system and the carriage storage system, so that materials can be conveyed among the platform system, the lifting system and the carriage storage system through the shuttle system and can be loaded and unloaded, and the shuttle system, the lifting system and the controller are connected.

Further, the shuttle system includes a shuttle plate and a guide rail;

the platform system is provided with a stacking area, a charging area and a material cache area, wherein the stacking area is used for stacking materials out of a warehouse, the material cache area is used for temporarily storing the whole stack of materials entering a carriage storage system, and the charging area provides a charging function for a shuttle plate for carrying the materials;

the lifting system comprises a lifting platform and a lifting support for supporting a lifter, or the lifting system adopts a stacker which comprises the lifting platform; the lifting system is used for ferrying the shuttle plate between the material buffer area and the goods shelf;

the carriage storage system comprises a plurality of layers of goods shelves arranged in the carriage;

the tracks are laid on the charging area, the material buffer area, the lifting platform and each layer of goods shelf, the tracks are communicated with one another, and the shuttle plates can freely shuttle among different areas along the tracks.

Further, the goods shelf is an unpowered goods shelf.

Further, the laying path of the track is: charging area-material buffer area-elevating platform-goods shelves.

Furthermore, a sensor connected with the controller is arranged on the guide rail, so that the shuttle plate can move forwards and stops according to the command of the controller.

Furthermore, the carriage storage system also comprises a positioning device which is arranged on one side of the lifting system and used for adjusting the parking position of the truck.

Further, be provided with the cargo bed on the elevating platform, the cargo bed upper berth is equipped with the guide rail with material buffer zone and goods shelves butt joint, the cargo bed can be followed the vertical center of elevating platform and is done rectilinear movement about the level, install location detection device on the cargo bed.

Furthermore, a positioning detection device connected with the controller is installed on the lifting platform.

Furthermore, the number of the tracks laid on the charging area, the material caching area, the lifting platform and each layer of goods shelf is two, the number of the shuttle plates is two, and the lifting system simultaneously conveys the two shuttle plates.

The invention also provides a method for loading and unloading the vehicle by adopting the automatic loading and unloading vehicle system, which is characterized by comprising the following steps:

automatic loading

S1, a truck arrives at the other side of the lifting system, the truck is parked to a loading and unloading point, and the position of the truck is adjusted according to a positioning device;

s2, after the materials are stacked in a material stacking area of the platform system, the materials are fed into a material buffer area and are placed on a guide rail, and a controller sends signals needing to be transported to a shuttle plate;

s3, receiving the material in a material cache region after the material signal is received by the shuttle plate, and supporting and moving the material to the edge of the material cache region;

s4, after receiving a signal that the shuttle plate is about to arrive, the lifting system adjusts the height of the lifting platform or adjusts the horizontal left and right positions and the height to be flush with the material buffer area at the same time to complete the butt joint of the guide rails, and then the shuttle plate moves to the lifting platform; after the lifting system receives a signal that the shuttle plate reaches the lifting platform, the height of the lifting platform is adjusted or the horizontal left and right positions and the height are adjusted simultaneously to be aligned with the shelf horizontally and the butt joint of the guide rails is completed;

s5, after receiving a signal that the butt joint of the guide rails is completed, the shuttle plate moves to the guide rails of the goods shelf, the goods and materials are transported and stored, and then the shuttle plate descends to place the goods and materials on the stored positions;

s6, the shuttle plate returns to the lifting platform along the guide rail, the lifting platform adjusts the height to be consistent with the material cache region after receiving a signal that the shuttle plate arrives at the lifting platform, and the shuttle plate moves into the material cache region after receiving the signal that the guide rail is butted, and waits for the next transportation;

s7, after the loading work is finished, the vehicle drives into a charging area to stand by and be charged after receiving a finishing signal;

automatic unloading is the reverse operation of automatic loading.

Further, when the shuttle plate is used for unloading, the goods shelves are stored from the bottom layer of the goods shelf, the goods shelves on the upper layer are installed after the bottom layer is filled with the goods shelves, and the goods shelves are stored from bottom to top;

when the shuttle plate is used for unloading, unloading is started from the top layer of the goods shelf, after the unloading of the top layer is finished, the next layer of unloading is carried out, and the goods shelf is unloaded from top to bottom.

The working principle is as follows:

the invention lays the rail of the shuttle system in the platform system, the lifting system and the carriage storage system, and simultaneously utilizes the lifting system to carry out transition between different heights of shelves in the platform and the carriage, so that the shuttle plate for consigning materials can freely shuttle in the platform system, the lifting system and the carriage storage system according to the rail, thereby completing the automatic loading and unloading operation between the materials in the material buffer area and the shelves in the carriage.

Has the advantages that:

1. the automatic operation of the material warehouse-out loading and unloading vehicle is realized, the labor intensity of manpower is reduced, and the operation efficiency is high;

2. the track is arranged only on the goods shelf in the carriage, and the track has no power mechanism, simple structure and small transformation difficulty.

3. Adopt multilayer goods shelves, the material is deposited efficiently, can carry out make full use of to the carriage space.

4. The shuttle plate can be configured according to the loading and unloading demand of the materials out of the warehouse, so that the equipment investment is reduced.

Drawings

FIG. 1 is a schematic diagram showing the relationship between the components according to the present invention.

Fig. 2 is a schematic structural diagram of the present invention.

Fig. 3 is a schematic diagram of operation with dual shuttling plates.

Fig. 4 is a schematic diagram of operation with a single shuttle plate.

Reference numerals:

the system comprises a platform system 1, a stacking area 11, a charging area 12, a material buffer area 13, a lifting system 2, a lifting platform 21, a lifting support 22, a compartment storage system 3, a shelf 31, a compartment 32, a truck 33, a positioning device 34, a shuttle system 4, a shuttle plate 41, a guide rail 42 and materials 5.

Detailed Description

The following detailed description will be made with reference to specific embodiments and accompanying drawings, but the present invention is not limited to the following embodiments.

Example 1

As shown in fig. 1-2, an intelligent automatic loading and unloading vehicle system comprises a platform system 1, a lifting system 2, a carriage 32 storage system 3, a shuttle system 4 connected with the platform system 1, the lifting system 2 and the carriage 32 storage system 3 in sequence, so that materials 5 can be transported among the platform system 1, the lifting system 2 and the storage system and loading and unloading vehicle operation can be carried out through the shuttle system 4, and the shuttle system 4 is connected with a controller.

The platform system 1 comprises a material 5 stacking area 11, a charging area 12 and a material caching area 13, wherein the material 5 stacking area 11 is positioned at a warehouse outlet, and the material 5 is stacked in the material 5 stacking area 11; the material buffer area 13 is positioned between the material 5 stacking area 11 and the lifting system 2 and is used for buffering the materials 5 which are conveyed by the forklift and are stacked, and waiting for the shuttle plate 41 to convey the materials to the carriage 32 storage system 3; the charging area 12 is provided with a charging device for charging the shuttle plate 41, and the shuttle plate 41 goes to the charging area 12 for charging when the amount of electricity of the shuttle plate 41 is lower than a set threshold value.

The elevator is arranged between the tail parts of the material buffer area 13 and the carriage 32 and is installed on the ground, the height of the elevator 21 is adjusted, the elevator 21, the height of the material buffer area 13 and the height of the goods shelf 31 are matched, the shuttle plate 41 is swung between the temporary storage area of the material 5 and the goods shelf 31 in the carriage 32, and the shuttle plate 41 can move to the goods shelf 31 in the carriage 32 to convey the material 5.

The lift system 2 includes a lift and a lift bracket 22 for supporting the lift.

The shuttle system 4 includes a shuttle plate 41, a rail on which the shuttle plate 41 travels; the shuttle plates 41 can be provided with a plurality of shuttle plates 41 according to the actual field and the requirements of the materials 5, and the shuttle plates 41 are provided with lifting devices which can lift and put down the stacked materials 5 from the ground;

the tracks are sequentially connected and laid on a charging area 12, a material buffer area 13 of the platform system 1, a lifting platform 21 of the lifting system 2 and a goods shelf 31 in the storage system; the tracks of the areas are communicated with each other, when the lifting platform 21 rises or falls to the same plane with the track of the material buffer area 13 or the track on the shelf 31, the tracks at the two ends are accurately butted, so that the shuttle plate 41 can freely pass through. Positioning detection means may be added to the lift system 2 to allow precise alignment of the tracks on the lift table 21 with the tracks on the material buffer 13 or the shelves 31. The guide rail 42 is also provided with a sensor which can make the shuttle plate 41 move forward and stop according to the loading, unloading and transportation requirements.

The carriage 32 storage system 3 comprises a plurality of layers of storage racks 31 arranged inside the carriage 32, the racks 31 are unpowered racks 31, and a track which is consistent with the track direction on the lifting platform 21 and can be butted with the racks 31 is laid on each layer of racks 31. For receiving the materials 5 transferred by the shuttle plate 41 and stacking the materials onto the single-layer or several-layer two-column storage shelves 31 inside the storage system 3 of the carriage 32. The carriage 32 stores each layer of shelves 31, and a guide rail 42 for moving the shuttle plate 41 is laid on each layer of shelves.

The storage system 3 of the carriage 32 further comprises a vehicle positioning device 34 which is arranged on one side of the lifting system 2 and is used for adjusting the left and right positions of the truck 33 and meeting the butt joint of the guide rail 42 of the lifting platform 21 and the guide rail 42 of the goods shelf 31 in the storage system 3 of the carriage 32. The vehicle positioning device 34 guides the vehicle to be parked at an accurate loading/unloading point.

The working mode is as follows:

automatic loading

The truck 33 reaches the other side of the lifting system 2, the accuracy of the left and right positions of the vehicle is adjusted by the vehicle positioning device 34, and the truck 33 is parked at a loading and unloading point; the materials 5 enter a material 5 stacking area 11 of the platform system 1 after being delivered from a warehouse, the materials 5 are stacked in the material 5 stacking area 11 in a manual or forklift mode, the materials 5 are conveyed into a material buffer area 13 after stacking processing and are placed on a guide rail 42, and a signal needing to be transported is sent to a shuttle plate 41 by a starting controller.

After receiving the signal of the material 5, the shuttle plate 41 receives the material 5 in the material buffer area 13, and lifts and moves the material 5 to the edge of the material buffer area 13; at this time, the lifting system 2 receives a signal that the shuttle plate 41 is about to arrive, the height of the lifter is adjusted to be flush with the buffer memory of the material 5 to complete the butt joint of the guide rail 42, and then the shuttle plate 41 transports the material 5 to the lifting platform 21 of the lifter; after receiving the signal that the shuttle plate 41 reaches the lifting platform 21, the lifter adjusts the height to be horizontally aligned with the lowest shelf 31 of the carriage 32 and completes the butt joint of the guide rail 42, and after receiving the signal that the guide rail 42 is completely butted, the shuttle plate 41 moves to enter the guide rail 42 at the lowest floor of the shelf 31 and transports the materials to the storage position; the shuttle plate 41 descends to place objects on the storage positions, then the objects return to the lifting platform 21 along the guide rail 42, the lifting platform 21 receives a signal that the shuttle plate 41 returns to the lifting platform 21, the height of the objects is adjusted to be consistent with the height of the material buffer area 13, the shuttle plate 41 receives a signal that the guide rail 42 is butted, the objects leave the lifting platform 21 and enter the material buffer area 13 to wait for next transportation, and after the first-layer shelf 31 is fully stored, the shuttle plate 415 transports the materials 5 to the upper-layer shelf 31 to be stored according to the process;

after the loading operation is finished, the vehicle enters the charging area 12 to be standby and charged after receiving the finishing signal.

During the automatic unloading operation, the shuttle plate 41 first picks up the goods from the uppermost layer of the shelf 31, conveys the goods to the material buffer area 13, and then manually conveys the goods to the warehouse, which is the reverse operation process of the automatic loading operation process.

Example 2

As shown in fig. 3, in embodiment 1, the lifting platform 21 of the elevator is provided with two cargo spaces, and can carry two shuttle plates 41 at the same time. The tracks laid on the charging area 12, the material buffer area 13 of the platform system 1, the lifting platform 21 of the lifting system 2 and the shelf 31 in the storage system are all set into two groups of tracks, which can be used for two different shuttle plates 41 to work simultaneously.

The working mode is as follows:

in this embodiment, the automatic loading is carried out by using two shuttle plates 41 simultaneously in addition to the operation method in embodiment 1.

After the controller is started, the two shuttle plates 41 work simultaneously, the stacked materials 5 are lifted and conveyed to the edge of the material buffer area 13, then the height is adjusted through the lifting mechanism, the two sets of rails are aligned simultaneously, and the two shuttle plates 41 convey the materials 5 to the rails of the shelf 31 simultaneously.

When the unloading work is carried out, the reverse operation is carried out.

Example 3

As shown in fig. 4, in embodiment 1, the elevating platform 21 of the elevator is provided with a cargo platform which can be displaced in the horizontal direction, so that the cargo platform can be horizontally displaced in the horizontal direction with respect to the center line of the elevating platform 21. While the tracks on the shelf 31 are arranged as two sets of tracks.

In this embodiment, a stacker may be used instead of the elevator. When the stacker is used, the vehicle positioning device 34 is not used, and the guide rail 42 on the goods shelf 31 can be aligned by means of the linear motion of the stacker itself on the horizontal plane and the height adjustment of the lifting platform 21. The stacker can also be used for loading and unloading more than two vehicles.

The working mode is as follows:

in this embodiment, the automatic loading is performed in such a manner that the loading platform is horizontally moved in accordance with the center line of the lifting platform 21 on the basis of the operation method in embodiment 1.

By adopting the elevator system, after the controller is started, when the lifting platform 21 conveys the shuttle plate 41 and carries out the rail alignment work, the lifting platform is firstly aligned with the plane of the lower layer rail, then the goods carrying platform moves left and right on the lifting platform 21, the rail on one side is aligned each time, the shuttle plate 41 conveys the goods to the storage position, and after the storage of the material 5 on the lower layer is finished, the storage on the upper layer is carried out. The unloading process is reverse operation.

After the stacker is adopted and the controller is started, when the lifting platform 21 conveys the shuttle plates 41 and carries out rail alignment work, the lifting platform is firstly aligned with the plane of the lower layer rail, the stacker moves along the rail of the stacker, the stacker aligns with the rail on one side every time, so that the shuttle plates 41 convey materials to a storage position, and after the storage of the materials 5 on the lower layer is completed, the upper layer is stored. The unloading process is reverse operation.

Claims

1. The utility model provides an intelligent automatic loading and unloading car system, includes platform system (1), operating system (2), carriage storage system (3) and the controller that connects the setting in proper order, its characterized in that still includes shuttle system (4), shuttle system (4) intercommunication platform system (1), operating system (2) and carriage storage system (3) make material accessible shuttle system (4) transport and carry out the loading and unloading car operation between platform system (1), operating system (2) and carriage storage system (3), shuttle system (4), operating system (2) are connected with the controller.

2. The auto-handler system according to claim 1,

the shuttle system (4) comprises a shuttle plate (41) and a guide rail (42);

the platform system (1) is provided with a stacking area (11), a charging area (12) and a material buffer area (13), wherein the stacking area (11) is used for stacking materials (5) which are delivered from a warehouse, the material buffer area (13) is used for temporarily storing the whole stack of materials (5) which are to enter a carriage storage system (3), and the charging area (12) provides a charging function for a shuttle plate (41) which carries the materials (5);

the lifting system (2) comprises a lifting platform (21) and a lifting support (22) for supporting a lifter, or the lifting system (2) adopts a stacker which comprises the lifting platform (21); the lifting system (2) is used for ferrying a shuttle plate (41) between the material buffer area (13) and the goods shelf (31);

the carriage storage system (3) comprises a plurality of layers of shelves (31) arranged inside a carriage (32);

the tracks (42) are laid on the charging area (12), the material buffer area (13), the lifting platform (21) and each layer of shelf (31), the tracks (42) are communicated with one another, and the shuttle plates (41) can freely shuttle among different areas along the tracks (42).

3. Auto-handler system according to claim 2, characterized in that the pallets (31) are unpowered pallets.

4. The automated handler system according to claim 2, wherein the track (42) has a lay path of: charging area (12), material buffer area (13), lifting platform (21) and shelf (31).

5. The auto-handler system according to claim 2, wherein the guide rail (42) is further provided with a sensor connected to a controller to allow the shuttle (41) to move forward and stop according to a command from the controller.

6. Auto-loading and unloading truck system according to claim 1, characterized in that the car storage system (3) further comprises a positioning device (34) arranged on one side of the lifting system (2) for adjusting the parking position of the trucks (33).

7. The automatic loading and unloading vehicle system according to claim 2, wherein a loading platform is arranged on the lifting platform (21), a guide rail (42) which is butted with the material buffer area (13) and the goods shelf (31) is paved on the loading platform, the loading platform can move linearly left and right horizontally along the vertical center of the lifting platform (21), and a positioning detection device is arranged on the loading platform; and a positioning detection device connected with the controller is arranged on the lifting platform (21).

8. The auto-handler system according to claim 4, wherein there are two sets of tracks (42) laid on the charging area (12), the material buffer area (13), the lifting platform (21), each layer of racks (31), and there are two shuttle plates (41), and the lifting system (2) simultaneously transports the two shuttle plates (41).

9. A method of loading and unloading vehicles using the auto-loading vehicle system of any of claims 1-8, comprising the steps of:

automatic loading

S1, a truck (33) arrives at the other side of the lifting system (2), the truck (33) is parked at a loading and unloading point, and the position of the truck (33) is adjusted according to a positioning device;

s2, after the materials (5) are stacked in a material stacking area (11) of the platform system (1), the materials are fed into a material buffer area (13) and are placed on a guide rail (42), and a controller sends signals needing to be transported to a shuttle plate (41);

s3, receiving the material (5) in a material buffer area (13) after the shuttle plate (41) receives the material (5) signal, and supporting and moving the material (5) to the edge of the material buffer area (13);

s4, after receiving a signal that the shuttle plate (41) is about to arrive, the lifting system (2) adjusts the height of the lifting platform (21) or adjusts the horizontal left-right position and the horizontal height at the same time to be flush with the material buffer area (13) to finish the butt joint of the guide rail (42), and then the shuttle plate (41) moves to the lifting platform (21); after the lifting system (2) receives a signal that the shuttle plate (41) reaches the lifting platform (21), the height of the lifting platform (21) is adjusted or the horizontal left-right position and the height are adjusted simultaneously to be horizontally aligned with the goods shelf (31) and the butt joint of the guide rails (42) is completed;

s5, after receiving a signal that the guide rail (42) is butted, the shuttle plate (41) moves to the guide rail (42) of the goods shelf (31), the goods and materials are transported and stored, and then the shuttle plate (41) descends to place the materials (5) on the stored positions;

s6, the shuttle plate (41) returns to the lifting platform (21) along the guide rail (42), the lifting platform (21) adjusts the height to be consistent with the material buffer area (13) after receiving a signal that the shuttle plate (41) arrives at the lifting platform (21), and the shuttle plate (41) moves into the material buffer area (13) after receiving the signal that the guide rail (42) is butted, and waits for the next conveying;

s7, after the loading work is finished, the vehicle drives into a charging area (12) to stand by and be charged after receiving a finishing signal; automatic unloading is the reverse operation of automatic loading.

10. The method of loading and unloading a truck of a truck system of claim 9,

when the shuttle plate (41) is unloaded, the goods shelves (31) are stored from the bottom layer of the goods shelves (31), the goods shelves (31) on the upper layer are installed after the bottom layer is filled, and the goods shelves (31) are stored from bottom to top;

when the shuttle plate (41) is used for unloading, unloading is started from the top layer of the goods shelf (31), after the unloading of the top layer is finished, the next layer of unloading is carried out, and the goods shelf (31) is unloaded from top to bottom.