Shipborne single-arm double-lifting-point adjustable small boat folding and unfolding device

Abstract

The invention discloses a shipborne single-arm double-lifting-point adjustable small boat folding and unfolding device, and belongs to the technical field of ships. The device comprises an arm retracting and releasing structure, a suspension arm structure and two slings, one end of the arm retracting and releasing structure is installed on a ship deck and can overhang or retract relative to a ship, the other end of the arm retracting and releasing structure is hinged to one end of the suspension arm structure, a first fixed pulley is arranged on the arm retracting and releasing structure, and one end of a sling is wound and penetrates through the first fixed pulley to be connected with a small boat; the suspension arm structure can rotate vertically, a second fixed pulley is arranged at the other end of the suspension arm structure, and one end of the other suspension cable penetrates through the second fixed pulley in a winding mode to be connected with the small boat. By rotating the suspension arm structure, the connection position of the slings penetrating through the second fixed pulley in a winding mode and the small boat can be changed, and adjustment of the suspension distance formed by the two slings is achieved. The boat lifting stability is improved, the boat lifting distance can be adjusted, and the boat lifting safety, flexibility and convenience are guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of ships, and in particular relates to a ship-borne single-arm double-hanging-point adjustable small boat retrieval and launching device. Background Art

[0002] The small boat launching and retracting device is a marine operation equipment used for hoisting and lowering small boats (rescue boats, lifeboats, work boats) at sea. The small boats are mainly used for marine operations, marine assistance, and escape of the crew of the ship. As various countries have increased their safety requirements for marine operation equipment, this launching and retracting device for small boats has attracted the attention of many countries.

[0003] The advantage of a double-hanging-point boat launching and retracting device is that the boat is relatively stable during the launching and retracting process, but generally two sets of launching and retracting devices are required, and two operators are required to operate synchronously to control the lowering and retracting of the boat. In the case of severe waves, it often happens that after the first hook is hung, the boat will swing forward and backward due to the action of the waves, and it is difficult to adjust the position of the second hook in real time, so it is very difficult to hang. At the same time, due to the action of wind and waves at sea, the boat may tilt in the air due to the different heights of the bow and stern during the launching and retracting process. At this time, it is difficult to adjust the length of the lifting rope in time, so one hook may be opened and a maritime accident may occur. Therefore, a new type of launching and retracting device is urgently needed to solve the above problems. Summary of the invention

[0004] In order to solve the problems in the prior art, the present invention proposes a ship-borne single-arm double-hanging-point adjustable small boat retrieval and launching device.

[0005] The technical solution of the present invention is as follows:

[0006] In the first aspect, the present invention discloses a ship-borne single-arm double-hanging-point adjustable boat launching and retracting device, comprising a launching and retracting arm structure, a boom structure, two slings and two winches; one end of the launching and retracting arm structure is installed on the deck of the ship and can be cantilevered or retracted relative to the ship, the other end of the launching and retracting arm structure is hinged to one end of the boom structure, a fixed pulley 1 is provided on the launching and retracting arm structure, one end of one of the slings is passed through the fixed pulley 1 and connected to the boat, the other end of the sling is connected to one of the winches, and the winch is used to provide a pulling force for launching and retracting the boat; the boom structure can be vertically rotated, and a fixed pulley 2 is provided at the other end of the boom structure, one end of another sling is passed through the fixed pulley 2 and connected to the boat, and the other end of the sling is connected to another winch; by rotating the boom structure, the position at which the sling passed through the fixed pulley 2 and connected to the boat can be changed, thereby realizing the adjustment of the suspension spacing formed by the two slings.

[0007] In a second aspect, the present invention discloses a method for launching and retracting a small boat using the device, comprising: when the small boat needs to be lowered to the sea surface, firstly, based on the position of the small boat in the ship, the target values ​​of the first angle, the second angle and the third angle when the sling is connected to the small boat are obtained; then, according to the three target values ​​obtained, the corresponding piston rods are driven by a hydraulic pump, thereby controlling the first boom link rod, the second boom link rod and the boom structure to rotate, and at the same time, three angle encoders will feedback the real-time values ​​of the above three angles, and the first boom link rod, the second boom link rod and the boom structure are adjusted according to the feedback real-time values ​​until the above three angles reach the target values, and then the sling is connected to the small boat through a locking structure, and then the joints 1 and 2 are rotated to suspend the second boom link rod outside the ship, and then the winch is rotated at the same time to lower the sling to stably lower the small boat to the sea surface;

[0008] When the boat needs to be retrieved into the ship, first rotate joints 1 and 2 to suspend the boom link 2 outside the ship, lower the sling passing through the fixed pulley 1, and connect the sling to the boat through the locking structure; then lower the sling passing through the fixed pulley 2, drive the piston rod 3 through the hydraulic pump, and then rotate the boom structure to adjust the lifting distance formed by the two slings, connect the sling passing through the fixed pulley 2 to the boat through the locking structure, and finally rotate the winch at the same time to retrieve the sling, and retrieve the boom link 2 into the ship, and then use the winch to lower the sling to put the boat on the ship;

[0009] Among them, when the posture of the boat changes during the process of folding and releasing, the boat can be stabilized again by adjusting joint three.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] 1. The present invention not only adopts a single arm for retrieval and deployment, but also retains the traditional double-hanging point retrieval and deployment method. The double-hanging point retrieval and deployment method makes the retrieval and deployment of the boat relatively stable throughout the whole process. The single-arm retrieval and deployment method effectively reduces the cost of the traditional double-hanging point retrieval and deployment device, such as economy, floor space and control difficulty.

[0012] 2. The present invention adjusts the joint 3 for connecting the boom link 2 and the boom structure to change the angle formed by the boom link 2 and the boom structure in the vertical direction, thereby adjusting the position of the boat on the retracting and releasing device of the present invention, and realizing timely and rapid adjustment of the horizontal boat hoisting distance D formed between the two locking parts, thereby overcoming the problem that it is difficult to adjust the length of the lifting rope in time in the prior art, which may cause a maritime accident, and at the same time overcomes the problem that the second hook is difficult to adjust the position in real time when the boat swings forward and backward due to the action of waves in the prior art, so it is very difficult to hang. The fixed pulley 1 on the boom link 2 can be installed at different positions of the boom link 2 as needed, so that the position of the locking part connected to the fixed pulley 2 passing through the fixed pulley 2 on the three-joint boom for lifting the boat can be adjusted. Therefore, the retracting and releasing device of the present invention has a high degree of freedom and a large working space. In addition, in the retracting and releasing device of the present invention, each joint is connected to a joint angle encoder, so the present invention can realize closed-loop feedback control based on the joint angle encoder to achieve higher control accuracy. Finally, the retractable and deployable device of the present invention adopts a lightweight structural design as a whole, which is used to reduce the overall mass of the three-joint crane arm while ensuring the structural strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0014] Figure 2 It is a structural schematic diagram of a three-joint boom base and a boom connecting rod 1;

[0015] Figure 3 It is a schematic diagram of the internal structure of the second boom connecting rod;

[0016] Figure 4 It is a schematic diagram of the local structure of the boom link three.

[0017] Explanation of the accompanying drawings: 1. three-joint crane arm; 2. fixed pulley 1; 3. fixed pulley 2; 4. first boat-lifting rope; 5. second boat-lifting rope; 6. first locking part; 7. second locking part; 8. fixed pulley base 1; 9. fixed pulley base 2; 10. three-joint crane arm base; 11. crane arm connecting rod 1; 12. crane arm connecting rod 2; 13. crane arm connecting rod 3; 14. joint 1; 15. joint 2; 16. joint 3; 17. piston cylinder 1; 18. piston cylinder 2; 19. piston cylinder 3; 20. piston rod 1; 21. piston rod 2; 22. piston rod 3; 23. angle encoder 1; 24. angle encoder 2; 25. angle encoder 3; 26. small boat. DETAILED DESCRIPTION

[0018] The present invention is further described and illustrated below in conjunction with specific embodiments. The embodiments are merely exemplary of the present disclosure and do not define the scope of limitation. The technical features of each embodiment of the present invention may be combined accordingly without conflicting with each other.

[0019] The structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0020] like Figure 1 As shown, it shows a ship-borne single-arm double-hanging-point adjustable boat launching and retracting device, which includes a three-joint lifting arm 1, a boat lifting winch 1, a boat lifting winch 2, a hydraulic pump and a hydraulic valve. The three-joint lifting arm 1 is a hydraulically driven three-joint single-arm structure. The three-joint lifting arm 1 has three joints 14, 15 and 16 that can rotate in the horizontal or vertical direction.

[0021] The three-joint boom 1 is composed of a three-joint boom base 10, a boom link 1 11, a boom link 2 12 and a boom link 3 13 as a main structure. The three-joint boom 1 is installed on the ship deck through the three-joint boom base 10, one end of the boom link 11 is hinged to the three-joint boom base 10 through a joint 14, and can rotate horizontally, and an angle encoder 23 is connected to the joint 14, and the angle encoder 23 is used to obtain the angle formed by the boom link 11 and the three-joint boom base 10 in the horizontal direction in real time, that is, to obtain the first angle in real time. The other end of the boom link 11 is hinged to one end of the boom link 2 12 through a joint 2 15, and the boom link 2 12 can rotate vertically; the joint 2 15 is connected to an angle encoder 2 24, and the angle encoder 2 24 is used to obtain the angle of the angle formed by the boom link 1 1 and the boom link 2 12 in the vertical direction in real time, that is, to obtain the second angle in real time. Horizontally rotating the boom link 1 11 can change the direction of the boom link 2 12, and vertically rotating the boom link 2 12 can achieve the extension or retraction of the boom link 2 12 relative to the ship. The other end of the boom link 2 12 is hinged to one end of the boom link 3 13 through a joint 3 16, and the joint 3 16 is also connected to an angle encoder 3 25, and the angle encoder 3 25 is used to obtain the angle of the angle formed by the boom link 2 12 and the boom link 3 13 in the vertical direction in real time, that is, to obtain the third angle in real time. Therefore, the invention can realize closed-loop feedback control based on the joint angle encoder to achieve higher control accuracy. The other end of the boom link 3 13 is provided with a fixed pulley 2 3. The three-joint boom base 10, the boom link 1 11, the boom link 2 12 and the boom link 3 13 are all designed with a lightweight structure, which is used to reduce the overall mass of the three-joint boom 1 while ensuring the structural strength.

[0022] like Figure 2 As shown, it is a schematic diagram of a three-joint boom base 10 and a boom link 11. The end of the three-joint boom base 10 that is not hinged to the boom link 11 is hinged with a piston cylinder 17 having a piston rod 20, and the piston rod 20 is hinged to the joint 14. The retracting and releasing device is hydraulically driven, and a hydraulic pump provides a power source for the hydraulic actuator. The piston cylinder 17, a hydraulic valve and a hydraulic pump are connected in sequence, and the piston cylinder 17 is connected to the hydraulic valve through a hydraulic pipeline. The hydraulic pump drives the piston rod 20, thereby controlling the joint 14 hinged to the piston rod 20 to rotate, and then the boom link 11 will rotate in the horizontal direction.

[0023] like Figure 1 and Figure 3As shown, a fixed pulley 1 is provided in the middle of the boom link 2 12 of the three-joint boom 1, one end of the first boat-lifting rope 4 of the boat-lifting winch 1 is wound through the fixed pulley 1 2, and the end of the first boat-lifting rope 4 is connected to the first locking portion 6, and the first boat-lifting rope 4 is connected to one of the lifting points on the boat through the first locking portion 6; the boat-lifting winch 1 provides the first boat-lifting rope 4 with the pulling force for retracting and releasing the boat. A piston cylinder 2 18 with a piston rod 21 and a piston cylinder 3 19 with a piston rod 3 22 are provided on both sides of the fixed pulley 1 on the boom link 2 12, respectively, and the piston cylinder 2 18 and the piston cylinder 3 19 are both hinged to the boom link 2 12, the piston rod 21 is hinged to the joint 2 15, and the piston rod 3 22 is hinged to the joint 3 16. The piston cylinder 2 18, a hydraulic valve and a hydraulic pump are connected in sequence, and the piston cylinder 2 18 is connected to the hydraulic valve through a hydraulic pipeline. The hydraulic pump drives the piston rod 2 21, thereby controlling the joint 2 15 hinged to the piston rod 21 to rotate, and then the boom connecting rod 2 12 will rotate in the vertical direction, thereby realizing the extension or retraction relative to the ship. The piston cylinder 3 19, a hydraulic valve and a hydraulic pump are connected in sequence, and the piston cylinder 3 19 is connected to the hydraulic valve through a hydraulic pipeline. The hydraulic pump drives the piston rod 3 22, thereby controlling the joint 3 16 hinged to the piston rod 3 22 to rotate, and the boom connecting rod 3 13 will rotate in the vertical direction. The piston cylinder 1 17, the piston cylinder 2 18 and the piston cylinder 3 19 are connected to different hydraulic valves and hydraulic pumps, and are connected to the hydraulic valve through different hydraulic pipelines.

[0024] like Figure 1 and Figure 4 As shown, one end of the second boat-lifting rope 5 of the boat-lifting winch 2 is wound through the fixed pulley 2 3, and the end of the second boat-lifting rope 5 is guided and connected with a second locking portion 7, and the second boat-lifting rope 5 is connected to another lifting point on the boat through the second locking portion 7; the boat-lifting winch 2 provides the second boat-lifting rope 5 with a pulling force for retracting and releasing the boat. When the joint 3 rotates, it will affect the posture of the boom link 3 13. By rotating the joint 3, the position of the second locking portion 7 for lifting the boat 26 on the three-joint boom 1 can be adjusted, so as to adjust the transverse boat-lifting distance D formed between the second locking portion 7 and the first locking portion 6.

[0025] The adjustment of the transverse boat crane spacing D formed between the second locking portion 7 and the first locking portion 6 can be actively adjusted according to the size of the boat 26, the mass distribution of the boat and the need for control process. The angle encoder 1 23, the angle encoder 24 and the angle encoder 3 25 respectively feedback the angle changes of the joint 1 14, the joint 2 15 and the joint 3 16, which can be used for the closed-loop control of the three-joint crane arm 1.

[0026] like Figure 3 and 4As shown, the fixed pulley 1 2 and the fixed pulley 2 3 are respectively installed on the fixed pulley base 1 8 and the fixed pulley base 2 9, wherein the fixed pulley base 2 9 is installed on the end of the boom link 3 13 that is not hinged to the boom link 2 12, and the fixed pulley base 1 8 can be installed at different positions of the boom link 2 12 as needed, and it is not necessary to be installed at the middle position of the boom link 2 12.

[0027] In the present invention, according to the size, mass distribution and sea wave conditions of the small boat 26 to be deployed, the fixed pulley base 1 8 is pre-selected at a suitable position, the first boat lifting rope 4 of the boat lifting winch 1 is guided to connect to the first locking part 6 through the fixed pulley 1 2, and the second boat lifting rope 5 of the boat lifting winch 2 is guided to connect to the second locking part 7 through the fixed pulley 2 3. The third angle is adjusted to a suitable size by rotating the joint 3 16, so that the transverse boat lifting distance D formed between the second locking part 7 and the first locking part 6 meets the required size for the small boat 26. When the retracting and launching device is connected to the small boat 26, the staff first connects the first locking part 6 to the small boat 26, then adjusts the joint 3 16, and then connects the second locking part 7 to the other side of the small boat 26. During the retracting and launching process, the angle changes of the joint 1 14, the joint 2 15 and the joint 3 16 are respectively fed back through the angle encoder 1 23, the angle encoder 2 24 and the angle encoder 3 25, so as to realize accurate control of the three-joint crane arm 1. According to the change of the posture of the boat 26 during the process of folding and releasing, the joint 3 16 is adjusted to ensure that the boat 26 is as stable as possible.

[0028] In a specific embodiment of the present invention, when it is necessary to put the boat 26 on the sea surface, firstly, based on the position of the boat 26 in the ship, the target values ​​of the first angle, the second angle and the third angle when the first locking part 6 and the second locking part 7 are connected to the boat 26 are obtained; then, according to the three target values ​​obtained, the corresponding piston rods are driven by the hydraulic pump to control the boom link 1 11, the boom link 2 12 and the boom link 3 13 to rotate, and at the same time, the three angle encoders will feedback the real-time values ​​of the above three angles, and the boom link 1 11, the boom link 2 12 and the boom link 3 13 will continue to be adjusted according to the feedback real-time values ​​until the above three angles reach the target values, and then the first locking part 6 and the second locking part 7 are connected to the boat, and then the lifting joint 1 14 and the joint 2 15 are rotated to suspend the boom link 2 12 outside the ship, and then the boat lifting winch 1 and the boat lifting winch 2 are rotated at the same time, and the first boat lifting rope 4 and the second boat lifting rope 5 are lowered to stably put the boat on the sea surface;

[0029] When the boat needs to be retrieved into the ship, firstly, the joint 14 and the joint 2 15 are rotated to suspend the boom link 2 12 out of the ship, and the first boat-lifting rope 4 wound through the fixed pulley 1 2 is lowered, and the first boat-lifting rope 4 is connected to the boat through the first locking portion 6; then the second boat-lifting rope 5 wound through the fixed pulley 2 3 is lowered, and the piston rod 3 22 is driven by the hydraulic pump to rotate the joint 3 16, and then the boom link 3 13 is rotated, and the second locking portion 7 is adjusted to connect with the first locking portion 6. A lateral boat hoist spacing D is formed between the first and second locking parts 6, and the second boat hoisting rope 5 wound around and passing through the fixed pulley 2 3 is connected to the boat through the second locking part 7, and finally the boat hoisting winch 1 and the boat hoisting winch 2 are rotated at the same time to retract the first boat hoisting rope 4 and the second boat hoisting rope 5, and then the joint 1 14 and the joint 2 15 are rotated to retract the boom link 2 12 into the ship, and finally the boat hoisting winch 1 and the boat hoisting winch 2 are used to lower the first boat hoisting rope 4 and the second boat hoisting rope 5 to place the boat on the deck of the ship.

[0030] When the boat 26 is suspended in the air, it is likely to be affected by the wind and waves at sea, resulting in different heights between the bow and stern, and then the boat 26 tilts in the air. At this time, the boat 26 can be quickly stabilized by rotating the joint 3 16, thereby avoiding the situation where a hook is opened and a maritime accident occurs.

[0031] The above-mentioned embodiments only express several implementation modes of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. For those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A ship-borne single-arm dual-hanging-point adjustable boat launching and retracting device, characterized in that: It includes a retractable arm structure, a boom structure, two slings and two winches; One end of the retractable arm structure is installed on the deck of the ship and can be extended or retracted relative to the ship. The other end of the retractable arm structure is hinged to one end of the boom structure. A fixed pulley (2) is provided on the retractable arm structure. One end of a sling is passed through the fixed pulley (2) and connected to the boat. The other end of the sling is connected to one of the winches. The winch is used to provide pulling force for retracting and launching the boat. The boom structure is capable of vertical rotation, and a second fixed pulley (3) is provided at the other end of the boom structure, one end of another sling is wound through the second fixed pulley (3) and connected to the boat, and the other end of the sling is connected to another winch; by rotating the boom structure, the position where the sling that is wound through the second fixed pulley (3) is connected to the boat can be changed, thereby realizing the adjustment of the sling spacing formed by the two slings.

2. The shipborne single-arm dual-hanging-point adjustable boat launching and retracting device according to claim 1, characterized in that: The retractable arm structure comprises a three-joint boom base (10), a boom connecting rod 1 (11) and a boom connecting rod 2 (12); A three-joint boom base (10) is installed on a ship deck; one end of a boom link rod 1 (11) is hinged to the three-joint boom base (10) and can rotate horizontally; the other end of the boom link rod 1 (11) is hinged to one end of a boom link rod 2 (12), and the boom link rod 2 (12) can rotate vertically; horizontal rotation of the boom link rod 1 (11) can change the direction of the boom link rod 2 (12), and vertical rotation of the boom link rod 2 (12) can achieve the extension or retraction of the boom link rod 2 (12) relative to the ship; the other end of the boom link rod 2 (12) is hinged to one end of a boom structure, and a fixed pulley 1 (2) is arranged on the boom link rod 2 (12).

3. The shipborne single-arm dual-hanging-point adjustable boat launching and retracting device according to claim 2, characterized in that: The boom link rod 1 (11) is hinged to the three-joint boom base (10) through a joint 1 (14), and an angle encoder 1 (23) is connected to the joint 1 (14). The angle encoder 1 (23) is used to obtain in real time the angle formed by the boom link rod 1 (11) and the three-joint boom base (10) in the horizontal direction, that is, to obtain a first angle in real time; the boom link rod 1 (11) is hinged to the boom link rod 2 (12) through a joint 2 (15), and an angle encoder 2 is connected to the joint 2 (15). (24), angle encoder 2 (24) is used to obtain in real time the angle formed by boom link 1 (11) and boom link 2 (12) in the vertical direction, that is, to obtain the second angle in real time; boom link 2 (12) is hinged to the boom structure through joint 3 (16), and joint 3 (16) is also connected with angle encoder 3 (25), angle encoder 3 (25) is used to obtain in real time the angle formed by boom link 2 (12) and the boom structure in the vertical direction, that is, to obtain the third angle in real time.

4. The shipborne single-arm dual-hanging-point adjustable boat storage and launching device according to claim 3, characterized in that: The end of the three-joint boom base (10) that is not hinged to the boom connecting rod (11) is hingedly connected to a piston cylinder (17) having a piston rod (20), and the piston rod (20) is hingedly connected to a joint (14); A piston cylinder 2 (18) having a piston rod 2 (21) and a piston cylinder 3 (19) having a piston rod 3 (22) are respectively arranged on both sides of the fixed pulley 1 (2); the piston cylinder 2 (18) and the piston cylinder 3 (19) are both hinged to the boom connecting rod 2 (12); the piston rod 2 (21) is hinged to the joint 2 (15); and the piston rod 3 (22) is hinged to the joint 3 (16).

5. The shipborne single-arm dual-hanging-point adjustable boat launching and retracting device according to claim 4, characterized in that: The retractable device also includes three hydraulic pumps and three hydraulic valves connected to the hydraulic pumps. The three hydraulic valves are respectively connected to piston cylinder one (17), piston cylinder two (18) and piston cylinder three (19) through different hydraulic pipelines; the hydraulic pump drives the piston rod, thereby controlling the joint articulated with the piston rod to rotate.

6. The shipborne single-arm dual-hanging-point adjustable boat launching and retracting device according to claim 1, characterized in that: The sling is connected to the boat via a locking structure.

7. A method for launching and retracting a small boat using the device of claim 5, characterized in that: include: When the boat needs to be lowered to the sea surface, firstly, based on the position of the boat in the ship, the target values ​​of the first angle, the second angle and the third angle when the sling is connected to the boat are obtained; then, according to the three target values, the corresponding piston rods are driven by the hydraulic pump to control the rotation of the boom link rod 1 (11), the boom link rod 2 (12) and the boom structure, and at the same time, the three angle encoders will feedback the real-time values ​​of the above three angles, and the boom link rod 1 (11), the boom link rod 2 (12) and the boom structure are adjusted according to the feedback real-time values ​​until the above three angles reach the target values, and then the sling is connected to the boat through the locking structure, and then the joint 1 (14) and the joint 2 (15) are rotated to suspend the boom link rod 2 (12) outside the ship, and then the two winches are rotated at the same time to lower the sling to steadily lower the boat to the sea surface; When the boat needs to be retrieved into the ship, firstly, the joint 1 (14) and the joint 2 (15) are rotated to suspend the boom link 2 (12) outside the ship, and the sling passed through the fixed pulley 1 (2) is lowered, and the sling is connected to the boat through the locking structure; then the sling passed through the fixed pulley 2 (3) is lowered, and the piston rod 3 (22) is driven by the hydraulic pump to rotate the boom structure, adjust the lifting distance formed by the two slings, and connect the sling passed through the fixed pulley 2 (3) to the boat through the locking structure, and finally the winch is rotated at the same time to retrieve the sling, and the boom link 2 (12) is retrieved into the ship, and then the winch is used to lower the sling to place the boat on the ship; When the boat (26) changes its posture during the process of being folded or released, the boat (26) can be stabilized again by adjusting the joint three (16).

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