Lift hook and method of transporting articles using lift hook

Abstract

The lifting hook has a main plate, first and second sliding plates, first and second bases, a pair of lifting hooks, a flywheel, and a rack. The first sliding plate and the second sliding plate are fixed to each other, are suspended from the radio remote control unmanned aerial vehicle, and are configured to slide up and down with respect to the main plate in a state of sandwiching the main plate. The first base and the second base are fixed to each other and slide up and down relative to the main board in a state of clamping the main board. The pair of lifting hooks is rotatably connected to the first base and the second base respectively. The flywheel is rotatably fixed to the main plate. And the rack is meshed with the flywheel and is fixed on the first sliding plate.

Description

Technical Field

[0001] One embodiment of the present invention relates to a sling for suspending an article from a radio-controlled unmanned aerial vehicle (hereinafter also referred to as a drone) for transportation, and a method for transporting an article using the sling. Background Art

[0002] In recent years, drones have been widely used in various fields. They can not only perform aerial photography but also serve as tools for transporting goods, materials, and other articles. For example, in Patent Documents 1 to 5, a sling (hereinafter referred to as a hoist hook) for transporting an article using a drone is disclosed.

[0003] (Prior Art Documents)

[0004] (Patent Documents)

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2002-128455

[0006] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2022-128632

[0007] Patent Document 3: Japanese Unexamined Patent Application Publication No. 2021-050064

[0008] Patent Document 4: Japanese Unexamined Patent Application Publication No. 2021-102521

[0009] Patent Document 5: Japanese Unexamined Patent Application Publication No. 2022-128628 Summary of the Invention

[0010] (Problems to be Solved by the Invention)

[0011] One of the tasks of one embodiment of the present invention is to provide a hoist hook having a novel structure and a method for transporting an article using such a hoist hook. Alternatively, one of the tasks of one embodiment of the present invention is to provide a hoist hook that can prevent an article from falling even when the drone suddenly drops unexpectedly, and a method for transporting an article using such a hoist hook.

[0012] (Measures for Solving the Problems)

[0013] One embodiment of the present invention is a lifting hook. The lifting hook has a main board, a first sliding board and a second sliding board, a first base and a second base, a pair of lifting hooks, a flywheel, and a rack. The first sliding board and the second sliding board are configured to be fixed to each other, suspended from a radio-controlled unmanned aerial vehicle, and configured to slide up and down relative to the main board while sandwiching the main board. The first base and the second base are configured to be fixed to each other and slide up and down relative to the main board while sandwiching the main board. The pair of lifting hooks are rotatably connected to the first base and the second base respectively. The flywheel is rotatably fixed to the main board. The rack meshes with the flywheel and is fixed to the first sliding board.

[0014] One embodiment of the present invention is a method of transporting an article. The method includes the steps of suspending the article from a lifting hook, using a radio-controlled unmanned aerial vehicle to move the lifting hook, and releasing the article from the lifting hook. The lifting hook has a main board, a first sliding board and a second sliding board, a first base and a second base, a pair of lifting hooks, a flywheel, and a rack. The first sliding board and the second sliding board are configured to be fixed to each other, suspended from a radio-controlled unmanned aerial vehicle, and configured to slide up and down relative to the main board while sandwiching the main board. The first base and the second base are configured to be fixed to each other and slide up and down relative to the main board while sandwiching the main board. The pair of lifting hooks are rotatably connected to the first base and the second base respectively. The flywheel is rotatably fixed to the main board. The rack meshes with the flywheel and is fixed to the first sliding board. Description of the Drawings

[0015] Figure 1 It is a schematic front view of the lifting hook according to an embodiment of the present invention.

[0016] Figure 2 It is a schematic rear view of the lifting hook according to an embodiment of the present invention.

[0017] Figure 3 It is a schematic perspective view of the lifting hook according to an embodiment of the present invention.

[0018] Figure 4 It is a schematic perspective view of the lifting hook according to an embodiment of the present invention.

[0019] Figure 5 It is a schematic perspective view of a part of the lifting hook according to an embodiment of the present invention.

[0020] Figure 6 It is a schematic front view of the lifting hook according to an embodiment of the present invention.

[0021] Figure 7 It is a schematic front view of the lifting hook according to an embodiment of the present invention.

[0022] Figure 8Schematic front view of the lifting hook according to an embodiment of the present invention.

[0023] Figure 9 Schematic front view of the lifting hook according to an embodiment of the present invention.

[0024] Figure 10 Schematic rear view of the lifting hook according to an embodiment of the present invention. Detailed implementation manners

[0025] Hereinafter, each embodiment of the invention disclosed in the present application will be described with reference to the drawings. However, the present invention can be implemented in various ways without departing from its gist, and should not be construed as being limited to the descriptions of the embodiments illustrated below.

[0026] For the sake of clarity, in the drawings, there are cases where the widths, thicknesses, shapes, etc. of each part are schematically shown compared with the actual state, but these are only examples and do not limit the interpretation of the present invention. In addition, in this specification and each drawing, elements having the same functions as those of the elements described with reference to the already shown drawings are given the same reference numerals, and there are cases where repeated descriptions are omitted.

[0027] Hereinafter, a lifting hook 100 according to an embodiment of the present invention and a method of transporting an article using the lifting hook 100 will be described. The lifting hook 100 is a hook configured to be able to be suspended from a drone and to be able to suspend an article. As described below, the lifting hook 100 will not accidentally open the hook during the transportation of the article, that is, during the flight of the drone, and can automatically open the hook when the article is lowered to the ground so as to release the goods from the lifting hook 100.

[0028] 1. Structure

[0029] Figure 1 and Figure 2 are respectively the schematic front view and rear view of the lifting hook 100 according to an embodiment of the present invention, Figure 3 and Figure 4 is a schematic perspective view of the lifting hook 100. Figure 5 is a schematic perspective view of the flywheel 160 mounted on the lifting hook 100 and its surrounding components. Figures 6 to 10 is a schematic front view or rear view showing the process of suspending an article on the lifting hook 100. In addition, for the sake of easy observation, Figures 7 to 9The latch 120, the first spring 110, etc. described below are not shown in the figure. Hereinafter, the vertical direction in the state where the lifting hook 100 is suspended by a drone or the like is referred to as the up-down direction or the z-direction. In addition, the normal direction of the main surface of the main board 102, which will be described later and is perpendicular to the z-direction, is referred to as the x-direction, and the direction perpendicular to the z-direction and the x-direction is referred to as the y-direction.

[0030] As can be seen from these drawings, the lifting hook 100 has the following structure as a basic structure. These structures may contain metals such as iron, aluminum, and copper, or alloys such as stainless steel and brass, or may contain resins such as epoxy resin, phenolic resin, and fluororesin. The resin may be a fiber-reinforced plastic containing glass fiber, carbon fiber, etc.

[0031] Main board 102

[0032] A pair of sliding plates (first sliding plate 104, second sliding plate 106)

[0033] Latch 120

[0034] A pair of bases (first base 130, second base 132)

[0035] First spring 110

[0036] Second spring 112

[0037] Hook 140

[0038] Rack 150

[0039] Pinion 152

[0040] Flywheel 160

[0041] (1) Main board

[0042] The main board 102 is a component that supports various structures mounted on the main board 102. The main board 102 is provided with grooves 102b and 102c for the hook 140 to rotate while moving up and down, a groove 102a for the latch 120 to move up and down, a groove 102f for the first base 130 and the second base 132 to move up and down (refer to Figure 7 .), a groove 102g for the first sliding plate 104 and the second sliding plate 106 to move up and down (refer to Figure 8 and Figure 9 .), etc. In addition, although not shown, the main board 102 is provided with an opening for inserting the shaft of the pinion 152.

[0043] (2) First sliding plate, second sliding plate, and first spring and second spring

[0044] The first sliding plate 104 and the second sliding plate 106 are fixed to each other in a manner that clamps at least a part of the main board 102 and faces each other through one or more sliding pins 170. The main board 102 is provided with one or more slots 102g for moving up and down in a state where the sliding pins 170 are inserted. Therefore, the main board 102 can move up and down relative to the first sliding plate 104 and the second sliding plate 106. In addition, the first sliding plate 104 and the second sliding plate 106 are respectively provided with suspension holes 104a, 106a for suspending the lifting hook 100 on the drone. The slot 102g provided in the main board 102 for the movement of the sliding pin 170 is formed such that when the main board 102 moves up and down relative to the first sliding plate 104 and the second sliding plate 106, the main board 102 does not overlap with the suspension holes 104a, 106a in the y direction.

[0045] A rack 150 extending in the vertical direction is fixed to the first sliding plate 104. In addition, the first sliding plate 104 is provided with a first spring 110. Specifically, one end of the first spring 110 is connected to the first sliding plate 104, and the other end is connected to the latch 120. Since the first spring 110 is also connected to the first sliding plate 104 and the latch 120 through the sliding pins 173, 172 respectively, the first spring 110 can rotate about the axis of the sliding pin 173, that is, the axis perpendicular to the main surface of the first sliding plate 104.

[0046] The second sliding plate 106 is provided with a second spring 112. Similarly to the first spring 110, one end of the second spring 112 is connected to the second sliding plate 106 through the sliding pin 173, and thus can rotate relative to the second sliding plate 106 about the axis of the sliding pin 173, that is, the axis perpendicular to the main surface of the second sliding plate 106.

[0047] (3) The first base, the second base and the latch

[0048] The first base 130 and the second base 132 are arranged to sandwich the main board 102 and are fixed to each other through a plurality of sliding pins 174, 176, 178. As described above, the main board 102 is provided with a slot 102b configured such that the sliding pin 178 for fixing the first base 130 and the second base 132 can penetrate and move up and down. Therefore, the first base 130 and the second base 132 can also move up and down relative to the main board 102.

[0049] The other end of the second spring 112 is connected to the second base 132 through a sliding pin 174. On the other hand, the other end of the first spring 110 is connected to the first base 130 through a latch 120. The latch 120 is a component whose function is to temporarily fix the positions of the first base 130 and the second base 132 relative to the main board 102, and has an L-shaped configuration. The other end of the first spring 110 is connected to the bent portion of the L-shaped configuration of the latch 120 through a sliding pin 172. In addition, as described above, the slot 102a is provided in the main board 102 in such a way that the sliding pin 172 connecting the latch 120 and the first spring 110 can penetrate and move up and down. In addition, one end of the latch 120 (one end of the two straight portions due to the bent portion) is connected to the first base 130 through a sliding pin 174. Therefore, the latch 120 can follow the up and down movement of the first base 130 and the second base 132, and while rotating relative to the first spring 110 and the first base 130 around the sliding pins 172 and 174 respectively, it moves in the up and down direction.

[0050] In addition, as Figure 3 shown, at the bottom of the slot 102a in the main board 102 through which the sliding pin 172 connecting the first spring 110 and the latch 120 penetrates, an exit slot 102d for temporarily fixing the sliding pin 172 is provided (refer to the dotted circle). Therefore, the slot 102a is an L-shaped slot, configured such that the long side portion of the L-shaped slot is parallel to the vertical direction (i.e., the direction in which the first sliding plate 104 and the second sliding plate 106 slide relative to the main board 102), and when the first base 130 and the second base 132 have finished sliding, the short side portion serves as the exit slot 102d for temporarily embedding the sliding pin 172. The position and size of the exit slot 102d are set such that in the state where the sliding pin 172 is embedded in the exit slot 102d, the restoring forces of the first spring 110 and the second spring 112 act, and the sliding pin 172 does not move in this state.

[0051] Here, the first spring 110 and the second spring 112 are respectively connected to the first sliding plate 104 and the second sliding plate 106 using the same sliding pin 173. Alternatively, the ends of the first spring 110 and the second spring 112 that are respectively connected to the first sliding plate 104 and the second sliding plate 106 overlap in the y direction. However, the first spring 110 extends toward one side of the hook 140, and the second spring 112 extends toward the other side of the hook 140. Therefore, the vectors of the restoring forces generated when the first spring 110 and the second spring 112 extend are in the z direction or approximately the z direction. Thus, the moving directions of the first base 130 and the second base 132 can be fixed in the approximate up and down direction, enabling the first base 130 and the second base 132 to move up and down stably.

[0052] (4) Hook

[0053] A pair of hooks 140 have a hook shape, a part of which is clamped between the first base 130 and the second base 132. The sliding pins 178 that fix the first base 130 and the second base 132 penetrate through the end of one hook 140, and the other sliding pins 178 penetrate through the end of the other hook 140 (refer to Figure 1 .). Thus, the pair of hooks 140 are respectively connected to the first base 130 and the second base 132. In addition, each hook 140 is also provided with a sliding pin 180 for rotation that penetrates through the main board 102. The sliding pins 178 are arranged in the slots 102b extending in the z direction provided on the main board 102. On the other hand, the sliding pins 178 for rotation are arranged in the curved or arc-shaped slots 102c provided on the main board 102. The slot 102c is clamped between a pair of linear slots 102b and is arranged such that the distance between them becomes farther as it gets closer to the suspension holes 104a, 106a. Therefore, when the first base 130 and the second base 132 move downward relative to the main board 102, the sliding pin 180 moves along the slot 102c. As a result, the pair of hooks 140 can be rotated relative to the first base 130 and the second base 132 respectively about an axis extending in the y direction to close. Conversely, when the first base 130 and the second base 132 move upward relative to the main board 102, the hooks 140 rotate in the opposite direction and open.

[0054] (5) Rack, pinion, and flywheel

[0055] The rack 150 is fixed to the first sliding plate 104 and extends in the vertical direction. The pinion 152 meshing with the rack 150 is arranged to penetrate through the main board 102. As Figure 5As shown, the flywheel 160 is rotatably fixed to the side of the second sliding plate 106 of the main board 102, and the flywheel 160 meshes with the pinion 152 directly or through one or more intermediate gears 154, 156. Details will be described below. When the drone suddenly ascends or descends while transporting an item suspended from the hook 140, the load of the item hanging on the hook 140 will temporarily change, causing the main board 102 to move up and down relative to the first sliding plate 104 and the second sliding plate 106. Since the rack 150 is fixed to the first sliding plate 104 and the pinion 152 is connected to the main board 102, the up and down movement of the main board 102 relative to the first sliding plate 104 and the second sliding plate 106 will cause the rack 150 to move up and down relative to the pinion 152. This movement causes the pinion 152 to rotate, thereby driving the flywheel 160. The flywheel 160 is a rotating body with a large moment of inertia. Although a large force is required to start the rotation, once it starts rotating, its moment of inertia is used to maintain the rotational motion. Therefore, in a stationary state, a large force is required to move the rack 150 up and down. In other words, the flywheel 160 is used as a resistance element that resists the up and down movement of the rack 150, that is, the up and down movement of the main board 102 relative to the first sliding plate 104 and the second sliding plate 106. The magnitude of the resistance of the resistance element can be adjusted by appropriately adjusting the structure of the flywheel 160. In addition, the arrangement of the rack 150, the pinion 152, the flywheel 160, etc. is not limited to the illustrated arrangement, and a part or all of them can be arranged on the side of the first sliding plate 104.

[0056] 2. Operation of the lifting hook and method of transporting an item

[0057] (1) Suspending an item

[0058] In the initial state, the sliding pin 172 passing through the bent portion of the latch 120 is not located in the exit groove 102d but in the long side portion of the groove 102a. In this state, the latch 120 is pulled upward by the restoring forces of the first spring 110 and the second spring 112. Therefore, the first base 130, the second base 132, and the hook 140 connected to them are also pulled upward, and the hook 140 remains open (see Figures 1 to 4 ).

[0059] When suspending an item, the first base 130 and the second base 132 are moved downward relative to the main board 102 so that the sliding pin 172 passing through the bent portion of the latch 120 engages with the exit groove 102d ( Figure 6 、 Figure 7 ). At this time, the sliding pin 180 passing through the groove 102c (see Figure 1 、 Figure 2 ) moves downward along the groove 102c. Therefore, the hook 140 rotates and closes ( Figure 6 、Figure 7 )。In addition, since the sliding pin 174 is located at the bottommost part of the groove 102f, the downward movement (on the hook 140 side) of the first base 130 and the second base 132 relative to the main board 102 is restricted. The state at this time is hereinafter referred to as the standby state. In the standby state, since the sliding pin 172 engages with the exit groove 102d, the latch 120 is locked and the hook 140 remains in the closed state. In this standby state, by hanging an item on the hook 140, the item can be suspended from the lifting hook 100. Usually, the item is placed on the ground or floor at this stage, so the full load of the item is not applied to the hook 140.

[0060] (2) Drone takeoff

[0061] After that, when the drone takes off and the item leaves the ground or floor, the hook 140 will bear the full load of the item. Thus, the main board 102 and the latch 120, together with the first base 130 and the second base 132 connected to the hook 140, move downward relative to the first sliding plate 104 and the second sliding plate 106. When the sliding pin 170 reaches the topmost part of 102g, the downward movement of the main board 102 is restricted. The state at this time is called the transportation state.

[0062] Here, the first sliding plate 104 is configured to temporarily unlock the latch 120 when switching from the standby state to the transportation state and lock the latch 120 again in the transportation state. Specifically, as Figures 6 to 9 shown, a protrusion 102e can be provided on the side surface of the first sliding plate 104. When the latch 120 in the standby state moves downward relative to the first sliding plate 104, the protrusion 102e causes the latch 120 to rotate around the sliding pin 174, and the sliding pin 172 slides in the x direction (i.e., along the short side portion) to displace from the exit groove 102d to the long side portion of the groove 102a. And when the latch 120 moves further downward, it causes the latch 120 to rotate in the opposite direction and the sliding pin 172 to engage with the exit groove 102d again. The protrusion 102e is configured to allow the sliding pin 172 to engage with the exit groove 102d in the standby state, and the bent portion of the latch 120 is located above the protrusion 102e. At the same time, when the main board 102 moves downward relative to the first sliding plate 104 and the second sliding plate 106, the sliding pin 172 engages with the exit groove 102d again, and the bent portion is located above the protrusion 102e. By arranging the protrusion 102e, when the main board 102 moves up and down relative to the first sliding plate 104 and the second sliding plate 106, the latch 120 abuts against the protrusion 102e, enabling the sliding pin 172 to reversibly move between the exit groove 102d and the long side portion. Therefore, the latch 120 can be locked not only in the standby state but also in the transportation state, and as a result, the hook 140 can always be kept in the closed state.

[0063] (3) Transportation and release of the article

[0064] After switching to the transportation state, the article is moved by the drone so as to be transported above a specified position. Then, the article is slowly lowered to the ground or the floor. When the article contacts the ground or the floor, the load of the article hanging on the hook 140 gradually decreases. Therefore, under the restoring forces of the first spring 110 and the second spring 112, the main board 102 moves upward relative to the first sliding plate 104 and the second sliding plate 106. When the load caused by the article disappears, the protrusion 102e abuts against the latch 120, and the sliding pin 172 moves from the exit groove 102d to the long side portion of the groove 102a (see Figure 8 .). That is, the latch 120 is unlocked. Thus, the restoring forces of the first spring 110 and the second spring 112 cause the sliding pin 172 to move upward along the groove 102a and return to the initial state, as a result of which the hook 140 is opened. Therefore, it is not necessary to manually remove the article from the lifting hook 100, which can save human resources and improve the work efficiency related to transportation. Therefore, the protrusion 102e has the function of locking the latch 120 in the transportation state and also has the function of automatically unlocking and opening the hook 140 when the drone lands.

[0065] Here, if the drone suddenly descends due to accidental reasons such as air flow influence or improper operation during flight, the load of the article will instantaneously disappear or rapidly decrease. At this time, if the lifting hook 100 has a tendency to return to the initial state after passing through the standby state, the hook 140 will be accidentally opened and the article will fall. However, in the lifting hook 100, the upward movement of the main board 102 generated when the load of the article instantaneously disappears or rapidly decreases is greatly restricted by the flywheel 160 that acts as a resistance to the relative vertical movement of the main board 102. In other words, the vertical movement is delayed by the flywheel 160. Further, when transporting the article, the latch 120 is locked, and the vertical movement of the latch 120 along the groove 102a is prohibited. Therefore, even when the load instantaneously disappears or suddenly decreases, the upward movement of the main board 102 relative to the first sliding plate 104 and the second sliding plate 106 is delayed, and the accidental opening of the hook 140 due to the unlocking of the latch 120 can be prevented, so that the article can be prevented from falling.

[0066] Thus, by using the lifting hook 100 according to an embodiment of the present invention, it is possible to prevent the article from falling due to air flow influence, improper operation of the drone, etc. when transporting the article by the drone. Further, the cumbersome work of removing the article from the drone can also be omitted. This not only saves human resources but also contributes to the safe and efficient transportation of the article.

[0067] Each of the embodiments described above as embodiments of the present invention can be implemented by being appropriately combined as long as they do not conflict with each other. In addition, appropriate addition, deletion, or design changes of constituent elements made by those skilled in the art based on each embodiment are included in the scope of the present invention as long as they have the gist of the present invention.

[0068] In addition, even other effects different from the effects obtained by the above-described embodiments, for effects that can be clearly obtained from the description of this specification or effects that can be easily predicted by those skilled in the art, are also understood to be effects that can be obtained by the present invention.

[0069] (Description of Reference Numerals)

[0070] 100: Lifting hook; 102: Main board; 102a: Groove; 102b: Groove; 102c: Groove;

[0071] 102d: Ejection groove; 102e: Protrusion; 102f: Groove; 102g: Groove; 104: First sliding plate;

[0072] 104a: Hanging hole; 106: Second sliding plate; 106a: Hanging hole; 110: First spring;

[0073] 112: Second spring; 120: Latch; 130: First base; 132: Second base; 140: Hook;

[0074] 150: Rack; 152: Pinion; 154: Intermediate gear; 156: Intermediate gear;

[0075] 160: Flywheel; 170: Sliding pin; 172: Sliding pin; 173: Sliding pin;

[0076] 174: Sliding pin; 176: Sliding pin; 178: Sliding pin; 180: Sliding pin.

Claims

1. A lifting hook, wherein, it includes: a main board; a first sliding plate and a second sliding plate, configured to be suspended from a radio-controlled unmanned aerial vehicle and configured to be fixed to each other and slide up and down relative to the main board while sandwiching the main board; a first base and a second base, configured to be fixed to each other and slide up and down relative to the main board while sandwiching the main board; a pair of hooks, rotatably connected to the first base and the second base respectively; a flywheel, rotatably fixed to the main board; and a rack, meshing with the flywheel and fixed to the first sliding plate.

2. The lifting hook according to claim 1, wherein, it further includes: a first spring and a second spring, a first end of the first spring is fixed to the first sliding plate in a manner that the first spring can rotate relative to the first sliding plate, a second end of the first spring is connected to the first base, a first end of the second spring is fixed to the second sliding plate in a manner that the second spring can rotate relative to the second sliding plate, a second end of the second spring is fixed to the second base in a manner that the second spring can rotate relative to the second base.

3. The lifting hook according to claim 2, wherein, it further includes: a latch, rotatably connected to the first spring and the first base in a manner that it can rotate relative to the first spring and the first base, and configured to slide up and down relative to the main board.

4. The lifting hook according to claim 3, wherein, the second end of the first spring is connected to the latch through a first sliding pin, the main board has an L-shaped groove allowing the first sliding pin to move in a penetrating state, a long side portion of the L-shaped groove is configured to be parallel to a direction in which the first sliding plate and the second sliding plate slide relative to the main board, a short side portion of the L-shaped groove is configured to temporarily embed the first sliding pin when the first base and the second base finish sliding.

5. The lifting hook according to claim 4, wherein, a side surface of the first sliding plate has a protrusion, and when the main board moves up and down relative to the first sliding plate and the second sliding plate, the protrusion allows the first sliding pin to move reversibly along the short side portion.

6. The lifting hook according to claim 1, wherein, the flywheel meshes with the rack through a pinion.

7. The lifting hook according to claim 1, wherein, the main board has a pair of arc-shaped grooves, second sliding pins and third sliding pins respectively penetrating through the pair of hooks move along the pair of curved grooves respectively.

8. A method for transporting an article, wherein, it includes: a step of suspending the article from the lifting hook; a step of moving the lifting hook using a radio-controlled unmanned aerial vehicle; and a step of releasing the article from the lifting hook, the lifting hook having: a main board; a first sliding plate and a second sliding plate, configured to be fixed to each other, suspended from a radio-controlled unmanned aerial vehicle, and configured to slide up and down relative to the main board while sandwiching the main board; A first base and a second base, which are configured to be fixed to each other and slide up and down relative to the main board while sandwiching the main board; A pair of hooks, which are rotatably connected to the first base and the second base; A flywheel, which is rotatably fixed to the main board; And A rack, which meshes with the flywheel and is fixed to the first sliding plate.

9. The method according to claim 8, Wherein, The lifting hook further has a first spring and a second spring, A first end of the first spring is fixed to the first sliding plate in such a way that the first spring can rotate relative to the first sliding plate, A second end of the first spring is connected to the first base, A first end of the second spring is fixed to the second sliding plate in such a way that the second spring can rotate relative to the second sliding plate, A second end of the second spring is fixed to the second base in such a way that the second spring can rotate relative to the second base.

10. The method according to claim 9, Wherein, The lifting hook further has a latch, which is connected to the first spring and the first base in such a way that it can rotate relative to the first spring and the first base, and is configured to slide up and down relative to the main board.

11. The method according to claim 10, Wherein, The second end of the first spring is connected to the latch through a first sliding pin, The main board has an L-shaped groove that allows the first sliding pin to move in a penetrating state, A long side portion of the L-shaped groove is arranged parallel to the direction in which the first sliding plate and the second sliding plate slide relative to the main board, A short side portion of the L-shaped groove is configured to temporarily embed the first sliding pin when the first base and the second base finish sliding.

12. The method according to claim 11, Wherein, A side surface of the first sliding plate has a protrusion, and when the main board moves up and down relative to the first sliding plate and the second sliding plate, the protrusion allows the first sliding pin to move reversibly along the short side portion.

13. The method according to claim 8, Wherein, The flywheel meshes with the rack through a pinion.

14. The method according to claim 8, Wherein, The main board has a pair of arc-shaped grooves, Second sliding pins and third sliding pins respectively passing through the pair of hooks move along the pair of arc-shaped grooves.

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