A trolley propulsion system and a ship unloader

Abstract

The present invention relates to the technical field of port equipment, and particularly relates to a trolley propulsion system and a ship unloader. The trolley propulsion system includes: a trolley body; a driving wheel hinged to the trolley body; a flexible track in contact with the driving wheel, and the driving wheel is adapted to travel relative to the flexible track in a preset direction under the drive of a driving unit; a protection device in direct or indirect contact with the flexible track, and adapted to cut off the power transmission from the driving unit to the driving wheel when the tension force of the flexible track is greater than a preset threshold. The trolley propulsion system provided by the present invention drives the driving wheel to travel relative to the flexible track in a preset direction under the drive of the driving unit, so as to drive the trolley body to travel in a preset direction, facilitating the adjustment of the position of the trolley body; by setting the protection device to cut off the power transmission from the driving unit to the driving wheel when the tension force of the flexible track is greater than the preset threshold, the driving unit is protected from damage, thereby prolonging the service life of the trolley.

Description

Technical Field

[0001] The present invention relates to the technical field of port equipment, and particularly relates to a trolley propulsion system and a ship unloader. Background Art

[0002] Chain bucket ship unloaders are widely used in port bulk cargo ship unloading terminals and have prominent environmental protection advantages. The chain bucket ship unloader unloads the materials in the ship by setting a chain bucket boom on the boom. To unload the materials at different distances from the land side, in the prior art, there is a device that fixedly connects the chain bucket boom to a trolley capable of moving along the boom, so as to drive the chain bucket boom to move along the boom through the movement of the trolley. However, during the working process, the attitude of the ship is often changed by waves, resulting in a collision between the bottom of the ship's cabin and the bottom of the chain bucket boom. At this time, the force exerted by the ship on the chain bucket boom is transmitted to the trolley through the rigid connection between the chain bucket boom and the trolley, thereby damaging the structure of the trolley. Once the driving mechanism of the trolley is damaged and the trolley cannot continue to move forward, the work will be seriously affected. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that the trolley is easily damaged by surge impact force, so as to provide a trolley propulsion system that can protect the trolley from surge impact force.

[0004] Another technical problem to be solved by the present invention is to overcome the defect in the prior art that the trolley of the ship unloader is easily damaged by surge impact force, so as to provide a ship unloader that can protect the trolley from surge impact force.

[0005] To solve the above technical problems, a trolley propulsion system provided by the present invention includes:

[0006] A trolley body;

[0007] A driving wheel, which is hinged to the trolley body;

[0008] A flexible track, which abuts against the driving wheel, and the driving wheel is adapted to travel relative to the flexible track along a preset direction under the drive of a drive unit;

[0009] A protection device, which directly or indirectly abuts against the flexible track, and is adapted to cut off the power transmission from the drive unit to the driving wheel when the tension force of the flexible track is greater than a preset threshold value.

[0010] Optionally, the trolley propulsion system further includes: a pressing wheel, the pressing wheel and the driving wheel are respectively arranged on opposite sides of the flexible track and abut against the flexible track to tension the flexible track.

[0011] Optionally, the protection device further includes: a clutch, which has an engaged state meshing with the drive unit and a disengaged state separated from the drive unit, and the clutch is adapted to switch between the engaged state and the disengaged state according to the magnitude of the force exerted on the pressing wheel by the flexible track.

[0012] Optionally, the protection device further includes: a connecting plate, which is hingedly connected to the trolley body, one end of the connecting plate is fixedly connected to the pressing wheel, and the end of the connecting plate away from the pressing wheel is fixedly connected to the clutch.

[0013] Optionally, the pressing wheel is adapted to move upward when the tension force of the flexible track is greater than a preset threshold value, and drive the clutch to move downward via the connecting plate, so that the clutch is separated from the drive unit;

[0014] Or, the pressing wheel is adapted to move downward when the tension force of the flexible track is less than or equal to the threshold value, and drive the clutch to move upward via the connecting plate, so that the clutch is engaged with the drive unit.

[0015] Optionally, the protection device further includes: a tensioning oil cylinder, one end of the tensioning oil cylinder is connected to the trolley body, and the other end is connected to the pressing wheel. The tensioning oil cylinder is adapted to provide a force for the pressing wheel in the direction of the flexible track and is adapted to expand and contract according to the magnitude of the force exerted on the pressing wheel by the flexible track.

[0016] Optionally, an oil cylinder hinge point is provided on the connecting plate, and the tensioning oil cylinder is hingedly connected to the connecting plate through the oil cylinder hinge point.

[0017] Optionally, the flexible track is a chain and the drive wheel is a sprocket.

[0018] Optionally, the trolley propulsion system further includes: trolley wheels, which are arranged at the bottom end of the trolley body and are adapted to provide guidance for the movement of the trolley body.

[0019] The ship unloader provided by the present invention includes:

[0020] The trolley propulsion system as described above.

[0021] The technical solution of the present invention has the following advantages:

[0022] 1. The trolley propulsion system provided by the present invention drives the driving wheels to travel along a preset direction relative to the flexible track under the drive of the drive unit, thereby driving the trolley body to travel along the preset direction, facilitating the adjustment of the position of the trolley body; by setting a protection device to cut off the power transmission from the drive unit to the driving wheels when the tension force of the flexible track is greater than a preset threshold value, preventing damage to the drive unit due to difficulty in driving the driving wheels when the tension force of the flexible track is too large. Moreover, after the drive unit cuts off the power transmission to the driving wheels, the drive unit is no longer rigidly connected to the driving wheels. Thus, when the trolley body is subjected to an external force along the traveling direction or in the opposite direction of the traveling direction, this force will not be transmitted to the drive unit, thereby protecting the drive unit from damage, reducing the failure rate of the trolley, and extending the service life of the trolley.

[0023] 2. The trolley propulsion system provided by the present invention sets the pressing wheel and the driving wheel on opposite sides of the flexible track respectively. The pressing wheel and the driving wheel located on opposite sides of the flexible track provide forces in different directions to the flexible track, thereby realizing the tensioning of the flexible track, and the overall structure is stable and reliable, increasing the stability of the system.

[0024] 3. The trolley propulsion system provided by the present invention sets a clutch to switch between the engaged state and the disengaged state according to the magnitude of the force exerted on the pressing wheel by the flexible track, realizing that the protection device switches between not cutting off the power transmission from the drive unit to the driving wheels and cutting off the power transmission from the drive unit to the driving wheels according to the magnitude of the tension force of the flexible track. The structure is simple, the operation is convenient, and the protection effect is good.

[0025] 4. The trolley propulsion system provided by the present invention sets a connecting plate to connect the pressing wheel and the clutch, realizing the movement of the clutch and the pressing wheel in opposite directions. Thus, when the tension force of the flexible track is greater than a preset threshold value, the pressing wheel moves upward and drives the clutch to move downward, thereby realizing the separation of the clutch from the drive unit. The structure is reasonable and the operability is good, further ensuring the safety of the system.

[0026] 5. The trolley propulsion system provided by the present invention sets a tensioning oil cylinder to provide a force towards the flexible track for the pressing wheel and expand and contract according to the magnitude of the reaction force exerted on the pressing wheel by the flexible track, thereby ensuring that the flexible track is in a reasonable tension state and realizing the movement of the pressing wheel when the tension force of the flexible track is greater than a preset threshold value.

[0027] 6. The trolley propulsion system provided by the present invention realizes the relative rotation between the connecting plate and the tensioning oil cylinder by hinging the tensioning oil cylinder to the connecting plate through an oil cylinder hinge point provided on the connecting plate. When the pressing wheel needs to move up and down, the distance between the pressing wheel and the fixed end of the tensioning oil cylinder is adjusted through the relative rotation between the tensioning oil cylinder and the connecting plate, ensuring the smooth up and down movement of the pressing wheel.

[0028] 7. The ship unloader provided by the present invention realizes the adjustment of the position of the trolley body by setting up the trolley propulsion system, thereby facilitating the loading and unloading of materials at different positions; when the tension force of the flexible track of the protection device of the trolley propulsion system is greater than the preset threshold, the power transmission from the drive unit to the drive wheel is cut off, effectively preventing the trolley body from transmitting the acting force to the drive unit under the impact of surges, thus effectively avoiding the damage of the trolley caused by the surge impact and reducing the failure rate of the ship unloader. Description of the Drawings

[0029] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a schematic structural diagram of the ship unloader of the present invention;

[0031] Figure 2 It is a schematic diagram of the clutch closed state of the trolley propulsion system of the present invention;

[0032] Figure 3 It is a schematic diagram of the clutch disconnected state of the trolley propulsion system of the present invention.

[0033] Description of the Reference Numerals:

[0034] 10. Frame main body; 11. Leg; 12. Main beam; 13. Running trolley; 20. Cabin; 30. Material; 40. Wharf foundation; 104. Chain bucket arm; 111. Hopper; 601. Boom; 401. Flexible track; 402. Drive wheel; 403. Trolley body; 404. Drive unit; 405. Clutch; 406. Connecting plate; 407. Connecting plate hinge point; 408. Tensioning oil cylinder; 409. Pressing wheel; 410. Trolley wheel; 411. Oil cylinder hinge point. Detailed Embodiments

[0035] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0037] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0039] Embodiment 1

[0040] Combined Figures 1 - 3 As shown, the trolley propulsion system provided in this embodiment includes:

[0041] Trolley body 403;

[0042] Drive wheel 402, hingedly connected to the trolley body 403;

[0043] Flexible track 401, abutted against the drive wheel 402, and the drive wheel 402 is adapted to travel relative to the flexible track 401 in a preset direction under the drive of the drive unit 404;

[0044] A protection device, directly or indirectly abutted against the flexible track 401, and adapted to cut off the power transmission from the drive unit 404 to the drive wheel 402 when the tension force of the flexible track 401 is greater than a preset threshold.

[0045] It should be noted that the preset direction is the extension direction of the flexible track 401, which refers to one of the "running directions" indicated by the arrow in Figure 2 , and it is the traveling direction of the trolley; to ensure the smooth travel of the driving wheel 402, the flexible track 401 needs to be in a tensioned state. When an external force acts on the trolley body, the flexible track 401 is stretched and the tension increases. When the tension is greater than the preset threshold, the protection device cuts off the power transmission from the driving unit 404 to the driving wheel 402. Here, the preset threshold is a fixed value set according to the performance of the flexible track 401; Figure 2 The following shows a schematic structural diagram of a set of the protection device. In actual application, the number of the protection devices is two sets, and the two sets of the protection devices are respectively arranged on both sides of the driving wheel 402 along the Figure 2 "running direction" in Figure 2 . Both sets of the protection devices can separately achieve the effect of cutting off the power transmission from the driving unit 404 to the driving wheel 402, and are suitable for protecting respectively when the trolley body 403 is subjected to external forces in two different directions along the

[0046] "running direction" in

[0047] . Optionally, the flexible track 401 is a chain, the driving wheel 402 is a sprocket, and the trolley propulsion system drives the trolley body 403 to travel along the extension direction of the chain by means of the cooperation of the sprocket and the chain.

[0048] Optionally, both ends of the flexible track 401 are fixedly arranged on the external structure. Further optionally, when the trolley propulsion system is applied to a ship unloader, both ends of the flexible track 401 are fixedly arranged at both ends of the boom 601.

[0048] The trolley propulsion system provided in this embodiment drives the driving wheel 402 to travel relative to the flexible track 401 along the preset direction under the drive of the driving unit 404, so as to drive the trolley body 403 to travel along the preset direction, which is convenient for adjusting the position of the trolley body 403; by setting the protection device to cut off the power transmission from the driving unit 404 to the driving wheel 402 when the tension of the flexible track 401 is greater than the preset threshold, it is prevented that when the tension of the flexible track 401 is too large, the driving unit 404 is damaged due to the difficulty in driving the driving wheel 402. And after the driving unit 404 cuts off the power transmission to the driving wheel 402, the driving unit 404 is no longer rigidly connected to the driving wheel 402. Thus, when the trolley body 403 is subjected to an external force along the traveling direction or in the opposite direction of the traveling direction, this force will not be transmitted to the driving unit 404, thereby protecting the driving unit 404 from being damaged, further reducing the failure rate of the trolley, and prolonging the service life of the trolley.

[0049] Specifically, the trolley propulsion system further includes: a pressing wheel 409. The pressing wheel 409 and the driving wheel 402 are respectively arranged on opposite sides of the flexible track 401 and are in contact with the flexible track 401 to tension the flexible track 401.

[0050] Optionally, the number of the pressing wheels 409 is two. The two pressing wheels 409 are respectively arranged on the front side and the rear side of the driving wheel 402 along the running direction of the driving wheel 402, so as to increase the stability of the force received by the flexible track 401.

[0051] In the trolley propulsion system provided in this embodiment, by arranging the pressing wheel 409 and the driving wheel 402 on opposite sides of the flexible track 401 respectively, the pressing wheels 409 and the driving wheel 402 on opposite sides of the flexible track 401 provide acting forces in different directions to the flexible track 401, thereby realizing the tension of the flexible track 401, and the overall structure is stable and reliable, increasing the stability of the system.

[0052] Specifically, the protection device further includes: a clutch 405. The clutch 405 has an engaged state meshing with the driving unit 404 and a disengaged state separated from the driving unit 404. The clutch 405 is adapted to switch between the engaged state and the disengaged state according to the magnitude of the acting force of the flexible track 401 received by the pressing wheel 409.

[0053] Optionally, the protection device is connected to the pressing wheel 409, that is, it is realized that the protection device is indirectly in contact with the flexible track 401. When the tension force of the flexible track 401 is different, the magnitude of the acting force of the flexible track 401 received by the pressing wheel 409 is different, so as to switch the engaged state and the disengaged state of the clutch 405 according to the magnitude of the acting force of the flexible track 401 received by the pressing wheel 409. When the tension force of the flexible track 401 is greater than the preset threshold, the acting force of the flexible track 401 received by the pressing wheel 409 increases, and the clutch 405 switches to the disengaged state, cutting off the power transmission from the driving unit 404 to the driving wheel 402; when the tension force of the flexible track 401 is less than or equal to the preset threshold, the acting force of the flexible track 401 received by the pressing wheel 409 is small, and the clutch 405 switches to the engaged state, and the driving unit 404 transmits power to the driving wheel 402. It should be noted that the two protection devices are respectively connected to one pressing wheel 409.

[0054] As a deformable embodiment, the protection device is not connected to the pressing wheel 409, but directly connected to the flexible track 401. Optionally, a sensor is provided on the protection device to sense the tension of the flexible track 401. When the sensor detects that the tension of the flexible track 401 is greater than the preset threshold, the clutch is directly controlled by the controller to switch to the disengaged state, and the clutch can also be switched between the engaged state and the disengaged state.

[0055] The trolley propulsion system provided in this embodiment realizes that the protection device switches between not cutting off the power transmission from the drive unit 404 to the drive wheel 402 and cutting off the power transmission from the drive unit 404 to the drive wheel 402 according to the magnitude of the tension of the flexible track 401 by setting the clutch 405 to switch between the engaged state and the disengaged state according to the magnitude of the force exerted on the pressing wheel 409 by the flexible track 401. The structure is simple, the operation is convenient, and the protection effect is good.

[0056] Specifically, the protection device further includes: a connecting plate 406, which is hingedly connected to the trolley body 403. One end of the connecting plate 406 is fixedly connected to the pressing wheel 409, and the end of the connecting plate 406 away from the pressing wheel 409 is fixedly connected to the clutch 405.

[0057] Optionally, a connecting plate hinge point 407 is provided on the trolley body. The connecting plate 406 is hingedly connected to the trolley body 403 through the connecting plate hinge point 407, and the connecting plate 406 can rotate around the connecting plate hinge point 407.

[0058] Specifically, the pressing wheel 409 is adapted to move upward when the tension of the flexible track 401 is greater than the preset threshold, and drive the clutch 405 to move downward through the connecting plate 406, so that the clutch 405 is separated from the drive unit 404;

[0059] Or, the pressing wheel 409 is adapted to move downward when the tension of the flexible track 401 is less than or equal to the threshold, and drive the clutch 405 to move upward through the connecting plate 406, so that the clutch 405 is engaged with the drive unit 404.

[0060] It should be noted that the "up" and "down" refer to Figure 2 the "up" and "down" indicated by the arrows in

[0061] The trolley propulsion system provided in this embodiment realizes the movement of the clutch 405 and the pressing wheel 409 in opposite directions by setting a connecting plate 406 to connect the pressing wheel 409 and the clutch 405. Thus, when the tension force of the flexible track 401 is greater than a preset threshold, the pressing wheel 409 moves upward to drive the clutch 405 to move downward, so that the clutch 405 is separated from the drive unit 404. The structure is reasonable and the operability is good, thereby ensuring the safety of the system.

[0062] Specifically, the protection device further includes: a tensioning oil cylinder 408. One end of the tensioning oil cylinder 408 is connected to the trolley body 403, and the other end is connected to the pressing wheel 409. The tensioning oil cylinder 408 is adapted to provide a force towards the flexible track 401 for the pressing wheel 409 and is adapted to expand and contract according to the magnitude of the force exerted on the pressing wheel 409 by the flexible track 401.

[0063] Optionally, the tensioning oil cylinder 408 and the trolley body 403 are hinged through a hinge point provided on the trolley body 403, and the tensioning oil cylinder 408 can rotate around this hinge point.

[0064] The trolley propulsion system provided in this embodiment ensures that the flexible track 401 is in a reasonable tension state and realizes the movement of the pressing wheel 409 when the tension force of the flexible track 401 is greater than a preset threshold by setting a tensioning oil cylinder 408 to provide a force towards the flexible track 401 for the pressing wheel 409 and expanding and contracting according to the magnitude of the reaction force exerted on the tensioning oil cylinder 408 by the flexible track 401.

[0065] Specifically, an oil cylinder hinge point 411 is provided on the connecting plate 406, and the tensioning oil cylinder 408 and the connecting plate 406 are hinged through the oil cylinder hinge point 411.

[0066] The trolley propulsion system provided in this embodiment realizes the relative rotation of the connecting plate 406 and the tensioning oil cylinder 408 by setting the tensioning oil cylinder 408 to be hinged to the connecting plate 406 through the oil cylinder hinge point 411 provided on the connecting plate 406. Thus, when the pressing wheel 409 needs to move up and down, the distance between the pressing wheel 409 and the fixed end of the tensioning oil cylinder 408 is adjusted through the relative rotation between the tensioning oil cylinder 408 and the connecting plate 406, ensuring the smooth up and down movement of the pressing wheel 409.

[0067] Specifically, the trolley propulsion system further includes: trolley wheels 410, which are arranged at the bottom end of the trolley body 403 and are adapted to provide guidance for the movement of the trolley body 403.

[0068] The following is a detailed description of the operation process of the trolley propulsion system when it is affected by surges:

[0069] When the trolley propulsion system is affected by a surge, the trolley body 403 connected to the chain bucket arm 104 has a tendency to move in the direction of the surge. Then, the flexible track 401 under the pressing wheel 409 is stretched, the tension of the flexible track 401 increases, the flexible track 401 has a tendency to straighten, and the upward force on the pressing wheel 409 from the flexible track 401 increases. When it exceeds the threshold of the tensioning cylinder 408, the tensioning cylinder 408 contracts, the cylinder piston rod retracts, and the pressing wheel 409 is lifted; when the piston rod retracts, the protection device rotates around the connecting plate hinge point 407. After rotation, the clutch 405 is in a disengaged state, and the drive unit 404 is disengaged from the drive wheel 402, and the drive unit 404 no longer drives the trolley to move; at this time, since the drive unit 404 is no longer connected to the drive wheel 402, the surge force acting on the trolley will not be transmitted to other structures. Even if the trolley moves in the opposite direction under the action of the surge, the drive unit 404 will not be damaged; then, after the surge ends, the tension of the flexible track 401 returns to its normal state, the piston rod of the tensioning cylinder 408 continues to extend, the clutch 405 is in an engaged state, the drive unit 404 continues to drive the drive wheel 402, and the trolley returns to its normal working state.

[0070] Embodiment 2

[0071] Combined with Figures 1 - 3 As shown, this embodiment provides a ship unloader, including:

[0072] The trolley propulsion system as described above.

[0073] The ship unloader provided in this embodiment realizes the adjustment of the position of the trolley body 403 by setting the trolley propulsion system, thereby facilitating the loading and unloading of materials at different positions; when the tension of the flexible track 401 of the protection device of the trolley propulsion system is greater than the preset threshold, the power transmission from the drive unit 404 to the drive wheel 402 is cut off, effectively preventing the trolley body 403 from transmitting the acting force to the drive unit 404 under the impact of the surge, thereby effectively avoiding the damage to the trolley caused by the surge impact and reducing the failure rate of the ship unloader.

[0074] Optionally, the ship unloader further includes: a frame main body 10, the frame main body 10 has portal legs 11, the portal legs 11 are connected to the wharf foundation 40. Optionally, rails are provided on the wharf foundation 40, and the portal legs 11 can move along the rails to drive the frame main body to move along the rails.

[0075] Optionally, the frame body 10 further includes a main beam 12. The main beam 12 includes a boom 601 extending beyond the portal leg 11. The trolley propulsion system is provided on the boom 601. The traveling trolley 13 is adapted to move along the boom 601. A chain bucket boom 104 is connected to the trolley body 403 of the traveling trolley 13. The boom 601 can drive the chain bucket boom 104 to move above the cabin 20. The trolley body 403 can drive the chain bucket boom 104 to move along the boom 601 to unload the material 30 in the cabin 20. Herein, the "above" refers to Figure 1 "up" indicated by the arrow in

[0076] Optionally, the boom 601 can move up and down in the vertical direction to drive the chain bucket boom 104 to move up and down, so as to unload the materials 30 at different heights in the cabin 20.

[0077] Optionally, the chain bucket boom 104 is provided with a hopper 111. The hopper 111 is adapted to load the material 30 and transport the material 30 to the top of the chain bucket boom 104, and then transfer the material to the shore via the belt conveyor system of the ship unloader.

[0078] It should be noted that when the trolley of the trolley propulsion system travels in the direction from the cabin 20 towards the dock foundation 40 as shown in Figure 1 the "traveling direction", the front feeding of the cutting edge line of the hopper mouth of the hopper 111 can be realized, ensuring the material taking efficiency.

[0079] Obviously, the above embodiments are only examples for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A trolley propulsion system, characterized in that, it includes: a trolley body (403); a driving wheel (402), which is hingedly connected to the trolley body (403); a flexible track (401), which abuts against the driving wheel (402), and the driving wheel (402) is adapted to travel relative to the flexible track (401) in a preset direction under the drive of a drive unit (404); a protection device, which directly or indirectly abuts against the flexible track (401), and is adapted to cut off the power transmission from the drive unit (404) to the driving wheel (402) when the tension force of the flexible track (401) is greater than a preset threshold; a pressing wheel (409), the pressing wheel (409) and the driving wheel (402) are respectively arranged on opposite sides of the flexible track (401) and abut against the flexible track (401) to tension the flexible track (401); The protection device further includes: a clutch (405), the clutch (405) has an engaged state meshing with the drive unit (404) and a disengaged state separated from the drive unit (404), and the clutch (405) is adapted to switch between the engaged state and the disengaged state according to the magnitude of the force exerted on the pressing wheel (409) by the flexible track (401); a connecting plate (406), which is hingedly connected to the trolley body (403), one end of the connecting plate (406) is fixedly connected to the pressing wheel (409), and the end of the connecting plate (406) away from the pressing wheel (409) is fixedly connected to the clutch (405); a tensioning oil cylinder (408), one end of the tensioning oil cylinder (408) is connected to the trolley body (403), and the other end is connected to the pressing wheel (409), the tensioning oil cylinder (408) is adapted to provide a force for the pressing wheel (409) in the direction towards the flexible track (401) and is adapted to expand and contract according to the magnitude of the force exerted on the pressing wheel (409) by the flexible track (401); The pressing wheel (409) is adapted to move upward when the tension force of the flexible track (401) is greater than a preset threshold, and drive the clutch (405) to move downward via the connecting plate (406) so that the clutch (405) is separated from the drive unit (404); or, the pressing wheel (409) is adapted to move downward when the tension force of the flexible track (401) is less than or equal to the threshold, and drive the clutch (405) to move upward via the connecting plate (406) so that the clutch (405) meshes with the drive unit (404).

2. The trolley propulsion system according to claim 1, characterized in that, an oil cylinder hinge point (411) is arranged on the connecting plate (406), and the tensioning oil cylinder (408) is hingedly connected to the connecting plate (406) through the oil cylinder hinge point (411).

3. The trolley propulsion system according to any one of claims 1-2, characterized in that, The flexible track (401) is a chain, and the drive wheel (402) is a sprocket wheel.

4. The trolley propulsion system according to any one of claims 1-2, characterized in that it further comprises: Trolley wheels (410), arranged at the bottom end of the trolley body (403), adapted to provide guidance for the travel of the trolley body (403).

5. A ship unloader, characterized in that it comprises: The trolley propulsion system according to any one of the above claims 1-4.

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