A shuttle vehicle capable of being automatically locked and unlocked with a forklift blade

Abstract

The present application relates to a kind of electromagnetic automatic locking and unlocking device for shuttle vehicle, comprising: electromagnet, it is arranged at the bottom of shuttle vehicle;First proximity sensor, it is arranged so that it can sense the presence of the metal spade knife, wherein the first proximity sensor is configured to send electromagnet energization signal to energize electromagnet when sensing the presence of the metal spade knife;And second proximity sensor, it is arranged so that it can sense the presence of the metal track, and the second proximity sensor is configured to send electromagnet de-energization signal to de-energize electromagnet when sensing the presence of the metal track.The present application also relates to a kind of shuttle vehicle.Through the present application, it can prevent shuttle vehicle from sliding when forklift spade knife shifts shuttle vehicle, and automatically release locking when forklift spade knife places shuttle vehicle into track to put down shuttle vehicle, to realize reliable and intelligent shuttle vehicle shift.

Description

TECHNICAL FIELD

[0001] The present invention relates generally to the field of intelligent warehousing and, in particular, to an electromagnetic automatic locking and unlocking device for a shuttle vehicle. Furthermore, the present invention also relates to a shuttle vehicle having such a device. BACKGROUND

[0002] High-density warehousing systems have been increasingly adopted in recent years due to their advantages of high density, efficiency, and safety compared to traditional warehousing systems. In a high-density warehousing system, shuttle vehicles run along different warehousing aisles to store and retrieve pallets, where the pallets are controlled by a radio controller. However, when a change of warehousing aisle is required, the shuttle vehicle is transported from one warehousing aisle to another by a forklift. During the transportation of the shuttle vehicle from one warehousing aisle to another, the driver must pay attention to the alignment of the shuttle vehicle. If any error occurs during the transportation of the shuttle vehicle, the shuttle vehicle is likely to fall, which can damage the external structure of the shuttle vehicle and sometimes even damage the internal components. This problem is more common in refrigerated warehouses, especially when the warehousing height is high. Currently, there are many solutions on the market to solve this problem. The most commonly used one is to use rubber strips at the bottom of the shuttle vehicle. However, there are problems with using rubber as a non-slip liquid:

[0003] (1) The surface of the non-slip rubber will deteriorate over time.

[0004] (2) At a higher operating level, the shuttle vehicle can slip off the forklift.

[0005] (3) In the case of sudden braking, the shuttle vehicle slips off the shovel of the forklift, causing the shuttle to fall.

[0006] Therefore, there is currently a need for a more reliable and intelligent shuttle vehicle transfer mechanism. SUMMARY

[0007] Starting from the prior art, the task of the present invention is to provide an electromagnetic automatic locking and unlocking device for a shuttle vehicle and a shuttle vehicle, by means of which the shuttle vehicle can be automatically locked by an electromagnet to prevent slipping when the forklift shovel transfers the shuttle vehicle and automatically unlocked to lower the shuttle vehicle when the forklift shovel places the shuttle vehicle into the track, thereby achieving a reliable and intelligent shuttle vehicle transfer.

[0008] In a first aspect of the present invention, this task is solved by an electromagnetic automatic locking and unlocking device for a shuttle vehicle, comprising:

[0009] An electromagnet arranged at the bottom of the shuttle and arranged such that a metal blade of the fork truck can come into contact with the electromagnet when placed at the bottom of the shuttle, wherein the electromagnet is configured to generate a metal-attracting magnetic field when energized to lock the metal blade with the electromagnet, and the electromagnet is further configured to not generate the magnetic field when de-energized;

[0010] A first proximity sensor arranged such that it can sense the presence of the metal blade when placed at the bottom of the shuttle, wherein the first proximity sensor is configured to send an electromagnet energization signal to energize the electromagnet when sensing the presence of the metal blade; and

[0011] A second proximity sensor arranged such that it can sense the presence of the metal track of the rack when the shuttle is placed on the metal track of the rack, and the second proximity sensor is configured to send an electromagnet de-energization signal to de-energize the electromagnet when sensing the presence of the metal track.

[0012] In the present invention, the term "shuttle" refers to a transport tool for storing and retrieving goods that runs on the metal track of the rack. The shuttle has, for example, wheels for movement on the metal track, or it relies on chain drive for movement. The term "metal blade" refers to a blade-shaped fork truck component made of metal for shoveling and lifting goods. It should be understood that the shuttle and the metal blade can take different forms, such as structure and material, in order to achieve the corresponding functions.

[0013] In a preferred embodiment of the present invention, it is provided that the electromagnet comprises a first electromagnet and a second electromagnet, which are respectively arranged such that a first tine and a second tine of the metal blade of the fork truck can respectively come into contact with the first and second electromagnets when placed at the bottom of the shuttle. Under the teaching of the present invention, a third electromagnet or more electromagnets can also be provided to interface with the metal blade or its tines. By providing multiple electromagnets, the reliability of the locking can be increased, and the falling can be better prevented.

[0014] In another preferred embodiment of the present invention, it is provided that the first proximity sensor comprises a first sub-proximity sensor and a second sub-proximity sensor, wherein the first sub-proximity sensor is arranged such that it can sense the presence of the metal blade when placed at the bottom of the shuttle in a first direction, and the second sub-proximity sensor is arranged such that it can sense the presence of the metal blade when placed at the bottom of the shuttle in a second direction opposite to the first direction. With this preferred embodiment, the blade can be reliably sensed and the electromagnetic locking between the shuttle and the blade can be reliably activated in the case of the blade shoveling the shuttle from different directions.

[0015] In an extended embodiment of the application it is provided that the electromagnet is cuboid-shaped; and / or

[0016] wherein the metal tines and / or the metal tracks are made of stainless steel and the proximity sensor is an inductive proximity sensor; and / or

[0017] wherein the electromagnet comprises an electromagnetic coil and a magnetic core being wound by the electromagnetic coil, wherein the magnetic core is magnetizable when the electromagnetic coil is energized and demagnetizable after the electromagnetic coil is de-energized.

[0018] In another extended embodiment of the application it is provided that the device further comprises a manual operation controller configured to energize or de-energize the electromagnet according to an instruction of a user. With this extended embodiment, manual intervention can be implemented when necessary to discharge a hazard or to perform a personalized operation.

[0019] In a second aspect of the application, the aforementioned task is solved by a shuttle comprising:

[0020] a shuttle body; and

[0021] a shuttle bottom comprising a first surface facing towards the shuttle, a second surface facing away from the shuttle and a side surface between the first surface and the second surface, the shuttle bottom comprising:

[0022] an electromagnet arranged at the second surface and arranged such that a metal tine of a forklift truck can come into contact with the electromagnet when placed at the shuttle bottom, wherein the electromagnet is configured to generate a metal-attracting magnetic field when energized to lock the metal tine with the electromagnet and the electromagnet is further configured to not generate the magnetic field when de-energized;

[0023] a first proximity sensor arranged at the second surface such that the first proximity sensor can sense a presence of the metal tine when placed at the shuttle bottom, wherein the first proximity sensor is configured to emit an electromagnet energization signal to energize the electromagnet when sensing the presence of the metal tine; and

[0024] a second proximity sensor arranged at the side surface proximate to the second surface such that it can sense a presence of a metal track of a rack when the shuttle bottom is placed on the metal track of the rack and the second proximity sensor is configured to emit an electromagnet de-energization signal to de-energize the electromagnet when sensing the presence of the metal track.

[0025] In a preferred embodiment of the application it is provided that the shuttle bottom has an opening at the location of the electromagnet to expose the electromagnet; and / or

[0026] The shuttle vehicle bottom has an opening at the location of the first proximity sensor to expose the first proximity sensor; and / or

[0027] The shuttle vehicle bottom has an opening at the location of the second proximity sensor to expose the second proximity sensor.

[0028] By the preferred solution, better locking and / or metal proximity sensing can be achieved, while the electromagnet and proximity sensors are hidden in the openings instead of protruding out of the bottom surface, thus protecting these components from wear and preventing these components from hindering the advance and retreat of the shovel.

[0029] In another preferred solution of the present application, it is provided that the first proximity sensor comprises a first sub-proximity sensor and a second sub-proximity sensor, wherein the first sub-proximity sensor is arranged such that the metal shovel is within the sensing range of the first sub-proximity sensor when placed at the shuttle vehicle bottom in a first direction, and the second sub-proximity sensor is arranged such that the metal shovel is within the sensing range of the second sub-proximity sensor when placed at the shuttle vehicle bottom in a second direction opposite to the first direction. Here, the term "sensing range" refers to the distance from the proximity sensor or the circular range with the distance as the radius, at which the detected object is just sensed by the proximity sensor when approaching the proximity sensor.

[0030] In yet another preferred solution of the present application, it is provided that the second proximity sensor comprises two second proximity sensors arranged on two sides opposite to each other, respectively, wherein the two second proximity sensors are configured to send an electromagnet de-energizing signal to de-energize the electromagnet only when both of the two second proximity sensors sense the presence of the metal track. By this preferred solution, the false de-energization of the electromagnet due to accidental touching of metal objects other than the metal track can be substantially prevented, because the de-energization signal is sent only when both of the two second proximity sensors arranged on the two sides detect the metal object (track), that is, when the metal object is detected near both sides of the shuttle vehicle, it can be substantially determined that the metal object is the metal track, at this time it can be reliably judged that the shuttle vehicle has been on the track, thus the electromagnet can be safely de-energized to achieve separation, and in other cases the de-energization signal of the electromagnet will not be accidentally triggered.

[0031] In a third aspect of the present application, the aforementioned task is solved by a method for transferring a shuttle vehicle according to the present application, comprising the following steps:

[0032] placing the metal shovel by the forklift at the shuttle vehicle bottom of the shuttle vehicle located on the first metal track;

[0033] sending an electromagnet energizing signal by the first proximity sensor to energize the electromagnet when the metal shovel is sensed to be in proximity;

[0034] locking the metal spade by the electromagnet;

[0035] transferring the shuttle vehicle from the first metal track to the second metal track by the forklift truck;

[0036] sending an electromagnet power-off signal by the second proximity sensor to power off the electromagnet when the second metal track is sensed to be close;

[0037] separating the metal spade from the shuttle vehicle bottom by the forklift truck.

[0038] In one preferred embodiment of the present application, it is specified that the method further comprises:

[0039] deactivating the second proximity sensor when the first proximity sensor is activated; and

[0040] deactivating the first proximity sensor when the second proximity sensor is activated.

[0041] In one extended embodiment of the present application, it is specified that:

[0042] sensing the metal spade close by the first proximity sensor comprises: sensing the metal of the metal spade by the first proximity sensor when the distance between the metal spade and the first proximity sensor is below a first threshold distance; and / or

[0043] sensing the metal track close by the second proximity sensor comprises: sensing the metal of the metal track by the second proximity sensor when the distance between the metal track and the second proximity sensor is below a second threshold distance.

[0044] In one extended embodiment of the present application, it is specified that the first threshold distance and / or the second threshold distance is 6mm to 60mm.

[0045] The present application has at least the following beneficial effects: first, the present application adopts an electromagnet to lock the metal spade of the forklift truck and the bottom of the shuttle vehicle, which reliably prevents accidental falling during the transfer of the shuttle vehicle, and at the same time, by adopting a proximity sensor to detect the metal spade and the metal track, the automatic power-on and power-off of the electromagnet is realized, thereby realizing the automatic locking and automatic unlocking of the shuttle vehicle and the metal spade, to simplify the transfer process and prevent misoperation.

[0046] The present application is based on the inventor's unique insight that by using electromagnets to lock the shuttle vehicle and the metal spade during the transfer process, the possibility of the shuttle vehicle falling or slipping during the transfer process can be greatly reduced compared to the rubber non-slip pads used in the prior art, because the electromagnetic attraction is significantly more stable and powerful than the friction generated by components such as rubber pads; however, since the electromagnets achieve locking and unlocking at the moment of power-on and power-off, it is often difficult to grasp the time point of this moment, and premature or delayed locking and unlocking can cause serious consequences (such as falling, overturning, etc.) in an instant, in view of this, the inventor introduces the corresponding metal sensing sensor to automatically determine the time point of locking and unlocking according to the unique characteristics of the shuttle vehicle transfer process (i.e. the time, state and position of locking and unlocking), thereby greatly improving the accuracy and reliability of the electromagnet locking and unlocking, thereby basically preventing misoperation and the corresponding risks caused by inaccurate locking or unlocking time points, and the automatic locking and unlocking operation also greatly simplifies the transfer process, making it possible to complete the transfer safely and quickly without excessive manual intervention. BRIEF DESCRIPTION OF DRAWINGS

[0047] The present application will be further described below with reference to the accompanying drawings in conjunction with the specific embodiments.

[0048] Figure 1 A schematic diagram of an electromagnetic automatic locking and unlocking device according to the present application is shown; and

[0049] Figure 2 A flowchart for operating a shuttle vehicle according to the present application is shown. DETAILED DESCRIPTION

[0050] It should be noted that the components in the various drawings can be shown exaggeratedly for illustration purposes, and are not necessarily to scale. In the various drawings, the same or functionally similar components are provided with the same reference numerals.

[0051] In the present application, unless specifically indicated, "arranged on", "arranged above" and "arranged over" do not exclude the presence of an intermediate object between them. In addition, "arranged on or above" only indicates the relative positional relationship between the two components, and in certain cases, such as after reversing the product direction, it can also be converted to "arranged below or below", and vice versa.

[0052] In the present application, each embodiment is only intended to illustrate the scheme of the present application and should not be understood as limiting.

[0053] In the present application, unless specifically indicated, the quantifier "one" does not exclude the scenario of multiple elements.

[0054] It should also be noted that, in the embodiments of the present application, only a part of components or assemblies can be shown for the sake of clarity and simplicity, but those skilled in the art can understand that, under the teaching of the present application, the required components or assemblies can be added according to the specific scene. In addition, the features in different embodiments of the present application can be combined with each other unless otherwise stated. For example, a feature in the second embodiment can replace a corresponding or functionally similar feature in the first embodiment, and the resulting embodiment also falls within the disclosure or description range of the present application.

[0055] It should also be noted that, in the scope of the present application, the expressions "same", "equal", "equal to" and the like do not mean that the numerical values of the two are absolutely equal, but allow a certain reasonable error, that is, the expressions also cover "substantially the same", "substantially equal", "substantially equal to". By analogy, in the present application, the terms "perpendicular to", "parallel to" and the like also cover the meanings of "substantially perpendicular to", "substantially parallel to".

[0056] In addition, the numbering of the steps of the methods of the present application does not limit the execution order of the method steps. Unless otherwise stated, the method steps can be executed in different orders.

[0057] First, the unique principle on which the present application is based is described.

[0058] The present application is based on the following unique insight of the inventor: through research, the present application finds that, by adopting an electromagnet to lock the shuttle vehicle and the metal spade in the transfer process, compared with the rubber non-slip pad adopted in the prior art, the possibility of the shuttle vehicle falling or sliding in the transfer process can be greatly reduced, because the electromagnetic attraction is obviously more stable and powerful than the friction generated by components such as rubber pads; however, since the electromagnet realizes locking and unlocking in the instant of power-on and power-off, and this time point is often difficult to grasp, and premature or delayed locking and unlocking can cause serious consequences (such as falling, overturning, overturning, etc.) in an instant, in view of this, the inventor introduces a corresponding metal sensing sensor to automatically determine the time point of locking and unlocking according to the unique characteristics of the shuttle vehicle transfer process (i.e. the time, state and position at which locking and unlocking should be performed), thereby greatly improving the accuracy and reliability of the electromagnet locking and unlocking, thereby substantially preventing misoperation and the corresponding risks caused by inaccurate locking and unlocking time points, and at the same time, the automatic locking and unlocking operation also greatly simplifies the transfer process, so that the transfer can be completed safely and quickly without too much manual intervention.

[0059] The present application is further described below with reference to the specific embodiments and the accompanying drawings.

[0060] Figure 1A schematic view of the electromagnetic automatic locking and unlocking device 100 according to the present application is shown.

[0061] As Figure 1 shown, the electromagnetic automatic locking and unlocking device 100 according to the present application (hereinafter also referred to as "device 100") is arranged at the shuttle bottom 101 (or simply "bottom") which comprises a first surface 101a facing towards the shuttle, a second surface 101b facing away from the shuttle, and side surfaces 101c and 101d between the first and second surfaces. In the present application, the term "shuttle" refers to a transport means for storing and retrieving goods which runs on metal rails of a goods rack. The shuttle has, for example, wheels for movement on the metal rails, or it depends on a chain drive for movement. In addition, the term "shuttle bottom" is to be understood as the shuttle part where the device 100 is located, that is to say, the term "shuttle bottom" also covers other shuttle parts for arranging the device 100, for example, the front, the rear, the upper part, etc.

[0062] The electromagnetic automatic locking and unlocking device 100 according to the present application comprises the following components:

[0063] • electromagnets 102 (also referred to as "electromagnets") arranged at the second surface 101b and arranged such that a metal blade (not shown) of a forklift truck is able to come into contact with the electromagnets 102 when placed at the shuttle truck bottom 101, in particular at the second surface 101b, wherein the electromagnets are configured to generate a magnetic field attracting metal objects, including the metal blade, when energized to lock the metal blade with the electromagnets 102, and the electromagnets 102 are further configured to not generate the magnetic field when de-energized so as not to lock or unlock the metal blade and the electromagnets 102. In the present embodiment, the electromagnets 102 comprise a first electromagnet 102a and a second electromagnet 102b, which are arranged in openings 103 of the second surface 101b, respectively, such that a better locking is achieved while hiding the electromagnets within the openings instead of protruding out of the bottom surface, thereby protecting the electromagnets from wear and preventing the electromagnets from hindering the advancement and retraction of the blade. The first and second electromagnets 102a, 102b are arranged such that a first tine and a second tine (not shown) of the metal blade of the forklift truck are able to come into contact with the first and second electromagnets 102a, 102b, respectively, when placed at the shuttle truck bottom 101. The electromagnets 102 can comprise, for example, an electromagnetic coil and a magnetic core (e.g. soft iron) wound by the electromagnetic coil, wherein the magnetic core is able to be magnetized when the electromagnetic coil is energized and demagnetized after the electromagnetic coil is de-energized. Other forms or numbers of electromagnets 102 are also conceivable under the teachings of the present invention. In the present embodiment, the first and second electromagnets 102a, 102b are configured in a cuboid shape to provide a flat locking surface. Other shapes of electromagnets 102 are also conceivable under the teachings of the present invention. The term "metal blade" refers to a blade-shaped forklift truck component made of metal for scooping and lifting cargo. It is to be understood that the shuttle truck and the metal blade can take different forms, e.g. structure and material, in order to achieve the respective functions. Here, the metal blade, metal track are preferably made of stainless steel, but it is also conceivable that they are made of other ferromagnetic metals as long as they are able to be attracted by the electromagnets.

[0064] • a first proximity sensor 104 arranged at the second surface 101b so that the first proximity sensor 104 can sense the approach of a metal shovel when it is placed at the shuttle bottom 101, in particular at the second surface 101b, wherein the first proximity sensor 104 is configured to emit an electromagnet energizing signal to energize the electromagnet 102 upon sensing the approach of the metal shovel. In the present embodiment, the first proximity sensor 104 comprises a first sub-proximity sensor 104a and a second sub-proximity sensor 104b, which are arranged in the opening 105 of the second surface 101b, respectively, so that a better metal detection is achieved, while hiding the sensors 104a, 104b within the opening, instead of protruding outside the bottom surface, thus protecting the sensors 104a, 104b from wear and preventing the sensor 104b from hindering the advancement and retraction of the shovel. The first sub-proximity sensor 104a is arranged so that it can sense the approach of a metal shovel when it is placed at the shuttle bottom 101 in a first direction, and the second sub-proximity sensor 104b is arranged so that it can sense the approach of a metal shovel when it is placed at the shuttle bottom in a second direction, opposite to the first direction. In the present embodiment, the first sub-proximity sensor 104a and the second sub-proximity sensor 104b are arranged at the two ends of the diagonal of the geometric arrangement area constituted by the first and second electromagnets 102a, 102b, in order to better identify the metal shovel approaching from both directions.

[0065] • a second proximity sensor 106 arranged on a side to be proximate to a second surface such that it can sense the proximity of the metal track when the shuttle vehicle's bottom 101 is placed on the metal track of the rack, and the second proximity sensor 106 is configured to emit a solenoid de-energizing signal to de-energize the solenoid upon sensing the presence of the metal track. In the present embodiment, the second proximity sensor 106 is also arranged within the opening 105 of the side 101c such that better metal detection is achieved while hiding the sensor 106 within the opening instead of protruding out of the bottom surface, thereby protecting the sensor from wear and tear and preventing the sensor 106 from obstructing the travel of the shuttle vehicle. In the present embodiment, the second proximity sensor 106 comprises two second proximity sensors arranged on two sides 101c and 101d opposite to each other respectively (i.e. one second proximity sensor 106 is arranged on each side, only one second proximity sensor 106 is shown in the present embodiment), wherein the two second proximity sensors 106 are configured to emit the solenoid de-energizing signal to de-energize the solenoid 102 only when both of the two second proximity sensors sense the proximity of the metal track. By doing so, it is possible to substantially prevent the solenoid from being erroneously de-energized due to a metal object other than the metal track, because only when both of the two second proximity sensors arranged on the two sides detect a metal object (the track), a de-energizing signal is emitted, that is, when a metal object is detected near both sides of the shuttle vehicle, it can be substantially determined that the metal object is the metal track, and at this time it can be reliably judged that the shuttle vehicle is on the track, and thus it is safe to de-energize the solenoid to achieve separation.

[0066] Figure 2 A flow of the method 200 for operating a shuttle vehicle according to the present application is shown.

[0067] At step 202, a metal spade is placed by a forklift at the bottom of the shuttle vehicle located on a first metal track. For example, the forklift translates the metal spade in a horizontal direction to the bottom of the shuttle vehicle.

[0068] At step 204, a solenoid energizing signal is emitted by the first proximity sensor to energize the solenoid upon sensing the proximity of the metal spade. For example, the first proximity sensor senses the presence of the metal spade when it enters its sensing range and emits a corresponding solenoid energizing signal.

[0069] At step 206, the metal spade is locked by the solenoid. The locking is achieved by the magnetic field generated by the energized solenoid, such that the metal spade is attracted to the solenoid under the action of the magnetic field.

[0070] At step 208, the shuttle vehicle is transferred by the forklift from the first metal track to a second metal track. The transfer may, for example, include the lifting of the shuttle vehicle in a vertical direction and the movement of the shuttle vehicle in a horizontal direction.

[0071] At step 210, a de-energize electromagnet signal is issued by the second proximity sensor to de-energize the electromagnet in the event that the second metal track is sensed to be in proximity. The de-energizing causes the magnetic field of the electromagnet to rapidly dissipate, thereby causing the metal spade to no longer be attracted to the electromagnet.

[0072] At step 212, the metal spade is separated from the shuttle base by the forklift. For example, the separation can include the forklift withdrawing the spade from the shuttle base in a horizontal direction.

[0073] While several embodiments of the application have been described, it is contemplated that those skilled in the art will conceive of many alterations, modifications, and improvements as the application is implemented. Accordingly, the appended claims are intended to embrace all such alterations, modifications, and improvements as fall within the scope of the application. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A shuttle vehicle capable of automatically locking and unlocking with a forklift blade, characterized in that, Its bottom includes: Two openings are arranged such that when the forklift's metal blade is placed at the bottom of the shuttle, the first and second teeth of the metal blade can respectively correspond to the positions of the two openings. An electromagnet is installed inside each of the two openings, and the surface of the electromagnet does not extend beyond the bottom surface of the shuttle. The electromagnet is arranged such that the forklift's metal blade can contact the electromagnet when placed at the bottom of the shuttle. The electromagnet is configured to generate a magnetic field that attracts metal when energized to lock the metal blade to the electromagnet, and the electromagnet is also configured not to generate the magnetic field when de-energized. A first proximity sensor is arranged to detect the presence of the metal shovel when it is placed at the bottom of the shuttle, wherein the first proximity sensor is configured to emit an electromagnet energizing signal upon sensing the presence of the metal shovel, thereby energizing the electromagnet. The first proximity sensor includes a first sub-proximity sensor and a second sub-proximity sensor, which are respectively arranged at opposite ends of the diagonal of the geometric arrangement area formed by the two openings; and A second proximity sensor is arranged such that it can sense the presence of the metal track when the shuttle is placed on the metal track of the shelf, and the second proximity sensor is configured to emit an electromagnet de-energizing signal to de-energize the electromagnet when the presence of the metal track is sensed, wherein the second proximity sensor is hidden in an opening on the side, and the metal of the metal track is sensed by the second proximity sensor when the distance between the metal track and the second proximity sensor is less than a second threshold distance, and the second threshold distance is 6 mm to 60 mm.

2. The shuttle as described in claim 1, characterized in that, The first sub-proximity sensor is arranged such that it can sense the presence of the metal shovel when the metal shovel is placed at the bottom of the shuttle in a first direction, and the second sub-proximity sensor is arranged such that it can sense the presence of the metal shovel when the metal shovel is placed at the bottom of the shuttle in a second direction opposite to the first direction.

3. The shuttle vehicle as described in claim 1, characterized in that, The electromagnet is rectangular in shape.

4. The shuttle as described in claim 1, characterized in that, The metal shovel teeth and / or metal rails are made of steel or stainless steel, and the proximity sensor is an inductive proximity sensor.

5. The shuttle as described in claim 1, characterized in that, The electromagnet includes an electromagnetic coil and a magnetic core wound around the electromagnetic coil, wherein the magnetic core can be magnetized when the electromagnetic coil is energized and demagnetized when the electromagnetic coil is de-energized.

6. The shuttle as described in claim 1, characterized in that, It also includes a manual operation controller, which is configured to energize or de-energize the electromagnet according to the user's instructions.

7. The shuttle as described in claim 1, characterized in that, It also includes the shuttle itself.

8. The shuttle as described in claim 1, characterized in that, The second proximity sensor includes two second proximity sensors respectively arranged on two opposite sides of each other, wherein the two second proximity sensors are configured to send an electromagnet de-energizing signal to de-energize the electromagnet only when both second proximity sensors detect the presence of the metal rail.

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