Passive wave-compensated crane

Abstract

The application relates to the technical field of ocean engineering equipment, and discloses a passive wave-compensated crane, which comprises a ship body, a rotating seat driven by a motor is arranged on the top of the ship body, a drum assembly is arranged on the top rear side of the rotating seat, a lifting arm is arranged on the top front side of the rotating seat through a hinged seat, the top of the drum assembly is fixedly connected with the top of the lifting arm through two rotating contraction ropes, a supporting table is arranged on the middle part of the top of the rotating seat, and a wave-compensation device is arranged on the top of the supporting table. The hydraulic cylinder assembly and the compensation limiting assembly are linked and matched, mechanical limiting is formed at the piston limit position, cylinder explosion accidents are effectively prevented, the gear and rack mechanism is used to realize 2:1 transmission ratio, pulley two is always located above pulley three, double pulleys are cooperatively pressure-bearing and load is evenly distributed, and the safety and operation stability of the wave-compensation device are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of marine engineering equipment technology, specifically to a passive wave-compensated crane. Background Technology

[0002] Patent application CN109987530A includes a piston tensioner, a gas-liquid accumulator, an electric or hydraulic winch, an air cylinder assembly, an oil replenishment device, and a venting device. The piston tensioner is connected to the gas-liquid accumulator via hydraulic lines. The air cylinder assembly is connected to the upper part of the accumulator. The oil replenishment device is connected to the hydraulic lines, and the venting device is connected to the upper part of the hydraulic cylinder. A cable is wound around the piston tensioner, with one end connected to the electric or hydraulic winch and the other end connected to the load. Advantages include: the passive wave-compensated piston tensioner can be used in offshore drilling equipment, offshore transfer equipment, offshore supply equipment, and marine cranes, offering high precision and rapid response. Its use of a cylinder and accumulator simplifies the structure of the compensation device and hydraulic system, making it easy to implement, fast-responding, and providing high tension control precision, safety, and reliability. It can also operate normally during power outages.

[0003] In most existing technologies, including the aforementioned patents, passive wave compensation devices generally suffer from the following technical problems: First, the hydraulic cylinder piston is prone to overstroke movement under wave impact. When the piston moves to the cylinder end cap, it will cause a violent impact, leading to safety accidents such as cylinder explosion, seal failure, or even cable breakage. Existing solutions lack an effective mechanical limit protection mechanism and cannot stop the piston in time when it reaches the limit position. Second, when the cable passes over the compensation pulley, it is usually only supported by a single pulley. Excessive force at a single point can easily cause local wear and fatigue fracture of the cable, which seriously affects the stability and service life of wave compensation.

[0004] To address the aforementioned issues, innovative design based on existing methods is urgently needed. Summary of the Invention

[0005] The problem that this invention aims to solve is that existing passive wave compensation devices lack effective mechanical limit protection, are prone to cylinder explosion accidents, and the steel cable is supported by only a single pulley, which easily leads to wear and breakage.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is: a passive wave-compensated crane, including a hull, a rotating base driven by a motor installed on the top of the hull, a drum assembly installed on the rear side of the top of the rotating base, a lifting arm installed on the front side of the top of the rotating base via a hinged seat, the top of the drum assembly being fixedly connected to the top of the lifting arm via two rotating and retracting ropes, a support platform installed in the middle of the top of the rotating base, and a wave compensation device provided on the top of the support platform; The wave compensation device includes a hydraulic cylinder assembly, a compensation limiting assembly, and a rope pressing assembly. One end of the steel cable on the drum assembly passes over the top of the middle part of pulley three at the top of the hydraulic cylinder assembly and pulley two at the top of the compensation limiting assembly, passes over the bottom of the middle part of pulley one at the top of the rope pressing assembly, passes over the top of the middle part of pulley one at the top of the crane boom, and is fixedly connected to a hook. An accumulator group is provided at the bottom of the support platform.

[0007] Preferably, the hydraulic cylinder assembly includes a hydraulic cylinder body, a connecting column, and a piston. The bottom of the hydraulic cylinder body is fixedly connected to the top of the support platform by bolts. The piston is fixedly installed at the end of the connecting column and is slidably disposed inside the hydraulic cylinder body. The other end of the connecting column passes through the top of the hydraulic cylinder body and is fixedly connected to a connecting seat. A support assembly is installed on the top of the connecting seat through an elastic component. The support assembly includes two fixed plates, which are fixedly connected by rollers. A pulley is rotated and sleeved on the outer surface of the rollers.

[0008] Preferably, the compensation limiting assembly includes a second support column and a limiting box. The bottom of the limiting box is fixedly connected to the top of the support platform by bolts. The bottom of the second support column extends through the top of the hull. A double-sided rack is fixedly connected to the bottom of the second support column. One side of the double-sided rack is slidably connected to the inner wall of the hull. The bottom of the double-sided rack extends through the top of the support platform and is slidably connected to the cavity at the top of the limiting protection frame at the bottom of the support platform. Gears are meshed on both sides of the double-sided rack, and a single-sided rack is meshed on one side of each gear.

[0009] Preferably, connecting strips are fixedly connected to both ends of one side of the connecting seat. The connecting strips movably pass through the top of the limiting box, and the bottom ends of the two connecting strips are rotatably connected to the middle of the gear through a rotating shaft.

[0010] Preferably, the top of the second support column is provided with a second pulley via a support assembly, and the second pulley is rotatably sleeved on the outer surface of the roller of the support assembly.

[0011] Preferably, the rope pressing assembly includes a support column, a pulley at the top of the support column, and a roller of the support assembly movably sleeved on the outer surface of the support column.

[0012] Preferably, the accumulator group includes multiple accumulators, which are fixedly connected by a central fixed shaft. The oil inlet of each accumulator is connected to a connecting plate, which is connected to a cavity at the bottom of the hydraulic cylinder body via a connecting pipe.

[0013] Preferably, the elastic component includes a fixed frame and springs, with a plurality of springs built into the fixed frame and fixedly connected to the bottom wall of the fixed frame. The top of the springs is fixedly connected to the bottom of the fixed plate, and the bottom of the fixed plate is inserted into the top of the springs.

[0014] Preferably, the top wall and bottom wall of the limiting box correspond to the upper and lower limits of the piston's movement, respectively.

[0015] Preferably, two rubber pads are fixedly installed on the top and bottom walls of the limiting box, respectively, and are positioned corresponding to the gears.

[0016] Compared with the prior art, the technical solution of the present invention has the following advantages: (1) The present invention forms a mechanical limit at the piston limit position through the linkage of the hydraulic cylinder assembly and the compensation limit assembly, which effectively prevents cylinder explosion accidents. At the same time, the 2:1 transmission ratio of the gear rack mechanism ensures that pulley two is always above pulley three, realizing the double pulleys working together to bear pressure and the load is evenly distributed, which significantly improves the safety and operational stability of the wave compensation device. When the hull descends, the nitrogen gas in the accumulator group expands and pushes the piston to move upward. The connecting seat drives the gear to roll upward along the single-sided rack through the connecting strip. The gear drives the double-sided rack to move upward, which in turn drives the pulley two at the top of the support column two to rise synchronously. When the piston moves upward and approaches its upper limit position, the gear moves upward to the inner top wall of the limit box and makes contact, creating a mechanical limit and preventing the piston from moving further upward, thus achieving upper limit protection for wave compensation. Similarly, when the hull rises, when the piston moves downward to its lower limit position, the gear makes contact with the inner bottom wall of the limit box, creating a mechanical limit and preventing the piston from moving further downward, thus achieving lower limit protection for wave compensation. This effectively prevents the piston from overtraveling due to wave impact, avoids the piston hitting the hydraulic cylinder end cover and causing cylinder explosion or seal failure, and ensures the crane's operational safety in harsh sea conditions.

[0017] (2) The steel cable on the drum assembly passes through pulley 2, pulley 3, pulley 1 of the rope pressing assembly and pulley 1 at the top of the boom in sequence before connecting to the hook. During the wave compensation process, since the displacement of pulley 2 is twice that of pulley 3, pulley 2 is always above pulley 3. When the steel cable passes through the two pulleys, they naturally fit together. The high-position pulley 2 bears the main tension and the low-position pulley 3 bears the auxiliary tension, which avoids local wear or fatigue fracture caused by excessive force at a single point. At the same time, the spring in the elastic assembly absorbs the impact of the steel cable tension fluctuation on pulley 3, so that the fixed plate maintains a stable posture under dynamic load, reduces vibration and sway, reduces dynamic wear between the steel cable and the pulley, significantly improves the service life of the steel cable and the pulley, and ensures the stability and reliability of the long-term operation of the wave compensation device. Attached Figure Description

[0018] Figure 1This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall top planar structure of the present invention; Figure 3 For the present invention Figure 2 Enlarged structural diagram at point A; Figure 4 This is a schematic diagram of the rear structure of the roll assembly of the present invention; Figure 5 This is a schematic diagram of the energy storage unit of the present invention; Figure 6 This is a schematic diagram of the wave compensation device of the present invention; Figure 7 This is a cross-sectional structural diagram of the limiting box of the present invention; Figure 8 This is a schematic diagram of the structure of the gear, single-sided rack, and double-sided rack of the present invention; Figure 9 For the present invention Figure 8 Enlarged structural diagram at point B; Figure 10 This is a cross-sectional structural diagram of the fixing frame of the present invention.

[0019] In the diagram: 1. Hull; 2. Rotary seat; 3. Drum assembly; 4. Lifting boom; 5. Steel cable; 501. Hook; 6. Support column one; 601. Pulley one; 7. Hydraulic cylinder body; 701. Connecting column; 702. Piston; 703. Connecting seat; 8. Support column two; 9. Fixing plate; 901. Pulley two; 902. Pulley three; 10. Connecting bar; 11. Limit box; 1101. Gear; 1102. Single-sided rack; 1103. Double-sided rack; 1104. Rubber pad; 1105. Limit protection frame; 12. Fixing frame; 1201. Spring; 13. Support platform; 14. Accumulator group. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0021] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "comprising" or "including," and similar terms used in this disclosure, mean that an element or object preceding the term encompasses the elements or objects listed following the term and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but may also include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0022] like Figures 1 to 10 As shown, the present invention provides a passive wave-compensated crane, including a hull 1, a rotating base 2 driven by a motor installed on the top of the hull 1, a drum assembly 3 installed on the rear side of the top of the rotating base 2, a lifting arm 4 installed on the front side of the top of the rotating base 2 via a hinge seat, the top of the drum assembly 3 being fixedly connected to the top of the lifting arm 4 via two rotating and retracting ropes, a support platform 13 installed in the middle of the top of the rotating base 2, and a wave compensation device provided on the top of the support platform 13. The wave compensation device includes a hydraulic cylinder assembly, a compensation limiting assembly, and a rope pressing assembly. One end of the steel cable 5 on the drum assembly 3 passes over the top of the middle part of the pulley 3 902 at the top of the hydraulic cylinder assembly and the pulley 2 901 at the top of the compensation limiting assembly, passes over the bottom part of the middle part of the pulley 1 601 at the top of the rope pressing assembly, passes over the top of the middle part of the middle part of the pulley 1 601 at the top of the crane boom 4, and is fixedly connected to the hook 501. An accumulator group 14 is provided at the bottom of the support platform 13.

[0023] In one embodiment of the present invention, the hydraulic cylinder assembly includes a hydraulic cylinder body 7, a connecting column 701, and a piston 702. The bottom of the hydraulic cylinder body 7 is fixedly connected to the top of the support platform 13 by bolts. The piston 702 is fixedly installed at the end of the connecting column 701 and is slidably disposed inside the hydraulic cylinder body 7. The other end of the connecting column 701 passes through the top of the hydraulic cylinder body 7 and is fixedly connected to a connecting seat 703. A support assembly is installed on the top of the connecting seat 703 by an elastic component. The support assembly includes two fixing plates 9, which are fixedly connected by rollers. A pulley 902 is rotatably sleeved on the outer surface of the rollers.

[0024] In one embodiment of the present invention, the compensation limiting assembly includes a second support column 8 and a limiting box 11. The bottom of the limiting box 11 is fixedly connected to the top of the support platform 13 by bolts. The bottom of the second support column 8 movably passes through the top of the hull 1. A double-sided rack 1103 is fixedly connected to the bottom of the second support column 8. One side of the double-sided rack 1103 is slidably connected to the inner wall of the hull 1. The bottom of the double-sided rack 1103 movably passes through the top of the support platform 13 and is slidably connected to the cavity at the top of the limiting protection frame 1105 at the bottom of the support platform 13. Gears 1101 are meshed on both sides of the double-sided rack 1103. A single-sided rack 1102 is meshed on one side of the gear 1101.

[0025] In one embodiment of the present invention, connecting strips 10 are fixedly connected to both ends of one side of the connecting seat 703. The connecting strips 10 movably pass through the top of the limiting box 11, and the bottom ends of the two connecting strips 10 are rotatably connected to the middle of the gear 1101 through a rotating shaft.

[0026] In one embodiment of the present invention, the top of the support column 2 8 is provided with a pulley 2 901 through a support assembly, and the pulley 2 901 is rotatably sleeved on the outer surface of the roller of the support assembly.

[0027] In one embodiment of the present invention, the rope pressing assembly includes a support column 6, and a pulley 601 at the top of the support column 6 is movably sleeved on the outer surface of the roller of the support assembly at the top of the support column 6.

[0028] In one embodiment of the present invention, the accumulator group 14 includes multiple accumulators, which are fixedly connected by a central fixed shaft. The oil inlet of each accumulator is connected to a connecting plate, which is connected to the cavity at the bottom of the hydraulic cylinder body 7 via a connecting pipe. The accumulator group 14 is provided with an air charging pipeline. One end of the air charging pipeline is connected to the air charging port of each accumulator, and the other end is connected to the outlet of a high-pressure nitrogen cylinder. A shut-off valve and a pressure reducing valve are sequentially arranged along the gas flow direction on the air charging pipeline. The shut-off valve is used to control the gas flow between the nitrogen cylinder and the accumulator. The pressure reducing valve is used to reduce the pressure of the high-pressure nitrogen output from the nitrogen cylinder to the pre-charge pressure required by the accumulator. A one-way valve is installed at the connection between the charging pipeline and the charging port of the accumulator to prevent the nitrogen in the accumulator from flowing back. The accumulator is filled with nitrogen. As a compressible medium, when the ship descends and the steel cable loosens, the nitrogen expands and squeezes the hydraulic oil in the accumulator into the hydraulic cylinder, pushing the piston upward to compensate for the slack in the steel cable. When the ship rises and the steel cable tightens, the piston moves downward to compress the hydraulic oil back to the accumulator and compress the nitrogen to store energy, thereby achieving passive wave compensation.

[0029] In one embodiment of the present invention, the elastic component includes a fixed frame 12 and springs 1201. Multiple springs 1201 are built into the fixed frame 12 and fixedly connected to the inner bottom wall of the fixed frame 12. The top of the springs 1201 is fixedly connected to the bottom of the fixed plate 9, and the bottom of the fixed plate 9 is inserted into the top of the springs 1201. The springs 1201 are used to absorb the impact of the tension fluctuation of the steel cable 5 on the pulley 902, so that the fixed plate 9 maintains a stable posture under dynamic load, reduces vibration, avoids the pulley 902 from swaying due to uneven force, and extends the service life of the pulley 902 and the steel cable 5.

[0030] In one embodiment of the present invention, the top wall and bottom wall of the limiting box 11 correspond to the upper and lower limits of the piston 702's movement, respectively. When the piston 702 moves to the limit position, the gear 1101 contacts the top wall or bottom wall of the limiting box 11 to achieve mechanical limiting.

[0031] As one embodiment of the present invention, two rubber pads 1104 are fixedly provided on the top and bottom walls of the limiting box 11, respectively, and are positioned corresponding to the gear 1101, so as to play a buffering role when the limiting contact occurs and reduce the impact.

[0032] Working principle and usage process of this invention: When the crane is in standby or stable working state, the nitrogen in the accumulator group 14 is in a balanced pressure state, the hydraulic oil in the hydraulic cylinder body 7 is in pressure balance with the hydraulic oil in the accumulator group 14, the piston 702 is located in the middle of the hydraulic cylinder body 7, the connecting seat 703 supports the fixed plate 9 and pulley 3 902 through the elastic component, pulley 2 901 is installed on the top of the compensation limit component through the support column 2 8, the steel cable 5 passes through pulley 2 901, pulley 3 902, pulley 1 601 of the rope pressing component and pulley 1 601 at the top of the boom 4 in sequence and then connects to the hook 501, the spring 1201 keeps the fixed plate 9 in a stable position and absorbs the impact of the tension fluctuation of the steel cable 5 on pulley 3 902; Wave compensation process during hull descent: As the hull 1 descends with the waves, the boom 4 and hook 501 move upward relative to the hull 1, and the steel cable 5 slackens. At this time, the nitrogen gas in the accumulator group 14 expands, forcing the hydraulic oil in the accumulator into the cavity at the bottom of the hydraulic cylinder body 7 through the connecting pipe. The high-pressure hydraulic oil pushes the piston 702 upward. The piston 702 pushes the connecting seat 703 upward a distance d through the connecting column 701. When the connecting seat 703 moves upward, on the one hand, it drives the pulley 902 at its top to move upward a distance d; on the other hand, the connecting seat 703 drives the two connecting bars 10 to move upward. The connecting bars 10 drive the gear 1101 to roll upward along the single-sided rack 1102. Since the gear 1101 meshes with the double-sided rack 1103 and the single-sided rack 1102 is fixed, the rolling of the gear 1101... The double-sided rack 1103 is driven to move upward a distance of 2d. The double-sided rack 1103 drives the pulley 901 at its top to move upward a distance of 2d through the support column 2 8. At this time, the displacement of pulley 901 is twice the displacement of pulley 3 902. Therefore, the position of pulley 901 is always higher than that of pulley 3 902. The pulley 901 at the higher position contacts and lifts the steel cable 5 first, compensating for the slack of the steel cable 5 and keeping the height of the hook 501 relatively stable. When the piston 702 moves upward and approaches the upper limit position, the gear 1101 moves upward to the inner top wall of the limit box 11 and contacts it, generating a mechanical limit and preventing the piston 702 from continuing to move upward. The rubber pad 1104 on the inner top wall of the limit box 11 plays a buffering role when in contact, reducing the impact and realizing the upper limit protection of wave compensation.

[0033] Wave compensation process during ship lifting: As the hull 1 rises with the waves, the boom 4 and hook 501 move downwards relative to the hull 1, tightening the steel cable 5 and exerting downward pressure on pulleys 901 and 902. Since pulley 901 is always higher than pulley 902, the higher pulley 901 bears the downward pressure from the steel cable 5 first. This pressure is transmitted to the connecting seat 703 through the support column 8, double-sided rack 1103, gear 1101, and connecting bar 10. Then, the connecting column 701 pushes the piston 702 downwards, squeezing the hydraulic oil at the bottom of the hydraulic cylinder body 7, causing the hydraulic oil to be forced back. The accumulator group 14 compresses nitrogen to store energy. At the same time, the connecting seat 703 drives the connecting bar 10 to move downward by a distance d, and the driving gear 1101 rolls downward along the single-sided rack 1102, thereby driving the double-sided rack 1103 to move downward by a distance 2d. The second support column 8 drives the second pulley 901 at its top to move downward by a distance 2d. When the piston 702 moves downward and approaches the lower limit position, the gear 1101 moves downward to the inner bottom wall of the limit box 11 and makes contact, generating a mechanical limit and preventing the piston 702 from continuing to move downward, thus realizing the lower limit protection of wave compensation. Throughout the compensation process, the spring 1201 within the elastic component maintains elastic support for the fixed plate 9, ensuring its stability and absorbing the impact of tension fluctuations in the steel cable 5 on the pulley 3 902. Since pulley 2 901 and pulley 3 902 maintain a 2:1 displacement ratio during movement, pulley 2 901 is always positioned above pulley 3 902. As the steel cable 5 passes over the two pulleys, it naturally adheres to their surfaces. The higher pulley 2 901 bears the primary tension, while the lower pulley 3 902 bears the auxiliary tension, achieving a uniform load distribution. The nitrogen gas in the accumulator group 14 continuously absorbs and releases hydraulic energy through expansion and compression, enabling the hydraulic cylinder assembly to automatically adjust the position of the piston 702 with the rise and fall of the waves, thereby achieving passive compensation for the tension of the steel cable 5, maintaining the relative stability of the height of the hook 501, and improving the stability and safety of offshore lifting operations.

[0034] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.

Claims

1. A passive wave-compensated crane, comprising a hull (1), characterized in that: The top of the hull (1) is equipped with a rotating base (2) driven by a motor. A drum assembly (3) is installed on the rear side of the top of the rotating base (2). A lifting arm (4) is installed on the front side of the top of the rotating base (2) through a hinge seat. The top of the drum assembly (3) is fixedly connected to the top of the lifting arm (4) through two rotating and retracting ropes. A support platform (13) is installed in the middle of the top of the rotating base (2). A wave compensation device is provided on the top of the support platform (13). The wave compensation device includes a hydraulic cylinder assembly, a compensation limiting assembly and a rope pressing assembly. One end of the steel cable (5) on the drum assembly (3) passes over the top of the middle part of the pulley three (902) at the top of the hydraulic cylinder assembly and the pulley two (901) at the top of the compensation limiting assembly, passes over the bottom part of the middle part of the pulley one (601) at the top of the rope pressing assembly, passes over the top of the middle part of the middle part of the pulley one (601) at the top of the crane arm (4) and is fixedly connected to the hook (501). An accumulator group (14) is provided at the bottom of the support platform (13).

2. A passive wave-compensated crane according to claim 1, characterized in that: The hydraulic cylinder assembly includes a hydraulic cylinder body (7), a connecting column (701), and a piston (702). The bottom of the hydraulic cylinder body (7) is fixedly connected to the top of the support platform (13) by bolts. The piston (702) is fixedly installed at the end of the connecting column (701). The piston (702) is slidably disposed inside the hydraulic cylinder body (7). The other end of the connecting column (701) passes through the top of the hydraulic cylinder body (7) and is fixedly connected to a connecting seat (703). A support assembly is installed on the top of the connecting seat (703) through an elastic component. The support assembly includes two fixing plates (9). The two fixing plates (9) are fixedly connected by rollers. The pulley three (902) is rotatably sleeved on the outer surface of the rollers.

3. A passive wave-compensated crane according to claim 2, characterized in that: The compensation limiting assembly includes a second support column (8) and a limiting box (11). The bottom of the limiting box (11) is fixedly connected to the top of the support platform (13) by bolts. The bottom of the second support column (8) extends through the top of the hull (1). A double-sided rack (1103) is fixedly connected to the bottom of the second support column (8). One side of the double-sided rack (1103) is slidably connected to the inner wall of the hull (1). The bottom of the double-sided rack (1103) extends through the top of the support platform (13) and is slidably connected to the cavity at the top of the limiting protection frame (1105) at the bottom of the support platform (13). Gears (1101) are meshed on both sides of the double-sided rack (1103). A single-sided rack (1102) is meshed on one side of the gear (1101).

4. A passive wave-compensated crane according to claim 2, characterized in that: Connecting strips (10) are fixedly connected to both ends of one side of the connecting seat (703). The connecting strips (10) move through the top of the limiting box (11). The bottom ends of the two connecting strips (10) are rotatably connected to the middle of the gear (1101) through a rotating shaft.

5. A passive wave-compensated crane according to claim 3, characterized in that: The top of the second support column (8) is provided with a second pulley (901) through the support assembly, and the second pulley (901) is rotatably sleeved on the outer surface of the roller of the support assembly.

6. A passive wave-compensated crane according to claim 4, characterized in that: The rope pressing assembly includes a support column (6), a pulley (601) at the top of the support column (6), and the outer surface of the roller of the support assembly movably sleeved on the top of the support column (6).

7. A passive wave-compensated crane according to claim 2, characterized in that: The accumulator group (14) includes multiple accumulators, which are fixedly connected by a central fixed shaft. The oil inlet of the accumulator is connected through a connecting plate, and the connecting plate is connected to the cavity at the bottom of the hydraulic cylinder body (7) through a connecting pipe.

8. A passive wave-compensated crane according to claim 2, characterized in that: The elastic component includes a fixed frame (12) and springs (1201). A plurality of springs (1201) are built inside the fixed frame (12) and fixedly connected to the bottom wall of the fixed frame (12). The top of the springs (1201) is fixedly connected to the bottom of the fixed plate (9), and the bottom of the fixed plate (9) is inserted into the top of the springs (1201).

9. A passive wave-compensated crane according to claim 3, characterized in that: The top and bottom walls of the limiting box (11) correspond to the upper and lower limits of the piston (702) movement, respectively.

10. A passive wave-compensated crane according to claim 3, characterized in that: The upper and lower inner walls of the limiting box (11) are each fixedly provided with two rubber pads (1104), which are positioned corresponding to the gear (1101).

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