Automatic hooking device for a ship crane
The automatic hook retraction device for marine cranes, utilizing a motor-driven rotation and telescopic mechanism combined with a conical slot design, solves the problems of hook swaying and equipment protection, thereby improving operational efficiency and equipment safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGSU MASADA HEAVY INDS
- Filing Date
- 2025-09-01
- Publication Date
- 2026-06-09
AI Technical Summary
Traditional marine cranes have unstable hooks that are prone to swaying after being retracted. The lack of coordinated design in various operating procedures leads to low operating efficiency, and the equipment is difficult to protect effectively in extreme weather conditions.
An automatic hook-retracting device is adopted, which includes a rotating mechanism, a telescopic adjustment mechanism, a retracting mechanism, and a lifting mechanism. The device uses a motor to drive the rotation, and a servo motor or stepper motor to control the extension and retraction of the telescopic arm and the retraction of the hook. Combined with the design of conical slots and blocks, it ensures the stability of the hook and the protection of the equipment.
It enables stable hook retraction, improves operational efficiency, and ensures the safety and lifespan of the equipment in adverse weather conditions.
Smart Images
Figure CN122166654A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of marine crane technology, and in particular to an automatic hook-retracting device for marine cranes. Background Technology
[0002] Marine cranes are key equipment in ship loading and unloading, offshore engineering, and other operations, undertaking important tasks such as lifting cargo and installing equipment. Their performance directly affects operational efficiency and safety. With the rapid development of the shipping industry and marine engineering, the requirements for automation and intelligence of marine cranes are increasing, especially in the hook raising and lowering operation. Traditional marine cranes suffer from numerous problems during hook retraction. Firstly, the lack of effective securing measures after hook retraction makes them prone to swaying during navigation or in severe weather conditions such as strong winds. This can lead to damage to the hull or other equipment, posing safety hazards. Secondly, the crane's rotation, extension, and hook lifting operations are independent and lack coordinated design, resulting in cumbersome operations and reduced efficiency when adjusting the working position and height. Furthermore, in extreme weather conditions, traditional cranes struggle to effectively protect the overall structure, making the equipment susceptible to damage and shortening its lifespan. Therefore, developing an automatic hook-retraction device for marine cranes that is structurally sound, easy to operate, and can effectively solve the above problems is key to improving the performance of marine cranes and meeting the needs of modern ship operations. Summary of the Invention
[0003] The purpose of this invention is to provide an automatic hook retraction device for marine cranes to solve the above-mentioned problems. This device addresses the issues of unstable and shaky hooks after being retracted in traditional marine cranes, low operational efficiency due to lack of coordination among various operating steps, and difficulty in effectively protecting the equipment under extreme weather conditions.
[0004] To address the aforementioned problems, this invention provides a technical solution: an automatic hook-retracting device for marine cranes, comprising a base, a rotating mechanism, a support base, a hydraulic cylinder, a connecting block, a movable arm, a lifting mechanism, a telescopic adjustment mechanism, a retracting mechanism, and a telescopic arm; the rotating mechanism is located inside the upper side of the base, and the support base is fixedly connected to the upper side of the rotating mechanism; the lower side of the hydraulic cylinder is movably connected to the center left side inside the support base, and the end of the piston rod on the upper side of the hydraulic cylinder is hinged to the lower right side of the movable arm; the connecting block is fixedly connected to the lower side of the movable arm, and the lower side of the connecting block is movably connected to the upper right side inside the support base; the left side of the telescopic adjustment mechanism is located inside the movable arm, and the right side of the telescopic adjustment mechanism is located inside the left side of the telescopic arm; the right side of the telescopic arm is provided with a retracting mechanism; the lifting mechanism is fixedly connected to the left end of the movable arm, and the right side of the lifting mechanism is connected to the retracting mechanism through the telescopic adjustment mechanism.
[0005] Preferably, the rotating mechanism includes a motor, a drive gear, a driven gear, and a rotating base; the motor is fixedly connected to the lower left side of the base, and the drive gear is fixedly connected to the upper output shaft of the motor; the lower side of the rotating base is movably connected to the upper center of the base, and the driven gear is fixedly connected to the lower side of the rotating base, and the driven gear is connected to the drive gear; the top of the rotating base is fixedly connected to the bottom of the support base.
[0006] Preferably, the motor is a servo motor or a stepper motor.
[0007] Preferably, the telescopic adjustment mechanism includes a second motor, a screw, a guide cavity, a mounting cavity, a slide, a rope, a first guide wheel, a slider, a second guide wheel, a third guide wheel, and a fourth guide wheel. The second motor is fixedly connected to the upper left side of the movable arm. The guide cavity is located inside the right side of the movable arm. The screw is movably connected to the upper side of the guide cavity, and the center of the left side of the screw is fixedly connected to the right output shaft of the second motor. The left side of the telescopic arm is movably connected to the inside of the guide cavity, and a threaded hole is provided on the upper left side of the telescopic arm for connection to the screw. The side has an internal mounting cavity; the mounting cavity has transverse grooves at both the front and rear positions; a guide wheel three is movably connected to the right side of the mounting cavity; the front and rear exteriors of the slider are movably connected to the inner sides of the corresponding grooves; guide wheels one and two are movably connected to the left and right sides of the slider, respectively; one end of the rope is fixedly connected to the upper left side of the mounting cavity, and the other end of the rope is fixedly connected to the left side of the guide hole cavity; a guide wheel four is movably connected to the lower right side of the mounting cavity; the wire rope of the retracting mechanism is connected to the retracting mechanism in sequence through guide wheels three, two, and four.
[0008] Preferably, the second motor is a servo motor or a stepper motor.
[0009] Preferably, the specific structure of the retracting mechanism includes a linkage rod, a sliding hole, a rack, a transmission gear, a first transmission shaft, a spring, a first sprocket, a chain, a protective cover, a second sprocket, a second transmission shaft, a slot, a locking block, a hook, a fifth guide wheel, and a movable block; the sliding hole is horizontally located inside the upper side of the telescopic arm, and a transmission gear is movably connected inside the lower right side of the sliding hole, with the first transmission shaft fixedly connected to the center of the transmission gear; the linkage rod is movably connected inside the sliding hole, and a rack is fixedly connected to the lower right side of the linkage rod, with the rack connected to the transmission gear; a spring is provided between the right side of the linkage rod and the right side of the sliding hole; a sprocket is fixedly connected to the rear exterior of the first transmission shaft. 1. A drive shaft 2 is fixedly connected to the center of both the front and rear of the movable block, and the drive shaft 2 is movably connected to the holes opened at the front and rear of the right side of the telescopic arm. In addition, a sprocket 2 is fixedly connected to the outside of the drive shaft 2 on the rear side, and the sprocket 2 is connected to the sprocket 1 through a chain. A slot is opened in the center of the lower side of the movable block, and a guide wheel 5 is movably connected inside the upper left side of the movable block. The sprocket 1, sprocket 2 and chain are all located inside the protective cover, and the protective cover is fixedly connected to the outside of the right rear side of the telescopic arm. The upper side of the locking block is connected to the slot, and a hook is provided at the bottom of the locking block. The wire rope of the retraction mechanism is fixedly connected to the center of the upper side of the locking block through the telescopic adjustment mechanism and the guide wheel 5.
[0010] Preferably, the slot is a tapered slot that matches the upper outer side of the card block.
[0011] Preferably, the lifting mechanism is a winch.
[0012] The beneficial effects of the present invention are: (1) The present invention has the characteristics of reasonable and simple structure, low production cost and convenient installation. The rotating mechanism driven by the motor can accurately adjust the working direction of the crane, and the operation is convenient and efficient.
[0013] (2) The present invention utilizes a screw-driven telescopic adjustment mechanism, combined with the linkage design of the guide wheel and the rope, to achieve telescopic boom extension and retraction while ensuring the stable output length of the wire rope during hoisting, thereby improving the stability and reliability of hoisting.
[0014] (3) The cooperation between the conical slot and the locking block in the retraction mechanism of the present invention can stably retract the hook and prevent the hook from shaking. When the telescopic arm is retracted, the linkage design of the linkage rod and the rack and gear can drive the movable block to rotate and retract, avoiding the hook from moving randomly in windy weather and ensuring the safety of operation.
[0015] (4) In this invention, the spring is set as a linkage rod to provide a reset elastic force, so that the device can quickly return to the initial state after the hook is lowered, which is convenient for subsequent operation. In extreme weather, the hydraulic cylinder can shorten and retract the entire boom, effectively protecting the equipment and extending the service life of the crane. Attached Figure Description
[0016] Figure 1This is a schematic diagram of the structure of the present invention.
[0017] Figure 2 for Figure 1 A sectional view.
[0018] Figure 3 This is a schematic diagram of the rotating mechanism.
[0019] Figure 4 This is a schematic diagram of the telescopic adjustment mechanism.
[0020] Figure 5 This is a schematic diagram of the retracting mechanism.
[0021] 1-Base; 2-Rotating mechanism; 3-Support seat; 4-Hydraulic cylinder; 5-Connecting block; 6-Moving arm; 7-Lifting mechanism; 8-Telescopic adjustment mechanism; 9-Retracting mechanism; 10-Telescopic arm; 21-Motor 1; 22-Driving gear; 23-Driven gear; 24-Rotating seat; 81-Motor 2; 82-Screw; 83-Guide hole cavity; 84-Mounting cavity; 85-Slide groove; 86-Rope; 87-Guide wheel 1; 8 8-Slider; 89-Guide wheel two; 810-Guide wheel three; 811-Guide wheel four; 91-Linkage rod; 92-Sliding hole; 93-Rack; 94-Transmission gear; 95-Transmission shaft one; 96-Spring; 97-Sprocket one; 98-Chain; 99-Guard cover; 910-Sprocket two; 911-Transmission shaft two; 912-Slot; 913-Slot block; 914-Hook; 915-Guide wheel five; 916-Moving block. Detailed Implementation
[0022] like Figure 1 and Figure 2 As shown, this specific embodiment adopts the following technical solution: an automatic hook-retracting device for a marine crane, including a base 1, a rotating mechanism 2, a support seat 3, a hydraulic cylinder 4, a connecting block 5, a movable arm 6, a lifting mechanism 7, a telescopic adjustment mechanism 8, a retraction mechanism 9, and a telescopic arm 10; the rotating mechanism 2 is provided inside the upper side of the base 1, and the support seat 3 is fixedly connected to the upper side of the rotating mechanism 2; the lower side of the hydraulic cylinder 4 is movably connected to the center left side inside the support seat 3, and the end of the piston rod on the upper side of the hydraulic cylinder 4 is hinged to the lower right side of the movable arm 6; the connecting block 5 is fixedly connected to the lower side of the movable arm 6, and the lower side of the connecting block 5 is movably connected to the upper right side inside the support seat 3; the left side of the telescopic adjustment mechanism 8 is located inside the movable arm 6, and the right side of the telescopic adjustment mechanism 8 is located inside the left side of the telescopic arm 10; the retraction mechanism 9 is provided on the right side of the telescopic arm 10; the lifting mechanism 7 is fixedly connected to the left end of the movable arm 6, and the right side of the lifting mechanism 7 is connected to the retraction mechanism 9 through the telescopic adjustment mechanism 8.
[0023] like Figure 3As shown, the specific structure of the rotating mechanism 2 includes a motor 21, a driving gear 22, a driven gear 23, and a rotating base 24; the motor 21 is fixedly connected to the lower left side of the base 1, and the driving gear 22 is fixedly connected to the upper output shaft of the motor 21; the lower side of the rotating base 24 is movably connected to the upper center of the base 1, and the driven gear 23 is fixedly connected to the lower side of the rotating base 24, and the driven gear 23 is connected to the driving gear 22; the top of the rotating base 24 is fixedly connected to the bottom of the support base 3.
[0024] Among them, motor 21 is a servo motor or a stepper motor.
[0025] like Figure 4 As shown, the specific structure of the telescopic adjustment mechanism 8 includes a second motor 81, a screw 82, a guide cavity 83, a mounting cavity 84, a slide 85, a rope 86, a first guide wheel 87, a slider 88, a second guide wheel 89, a third guide wheel 810, and a fourth guide wheel 811; the second motor 81 is fixedly connected to the upper left side of the movable arm 6; the guide cavity 83 is opened inside the right side of the movable arm 6; the screw 82 is movably connected to the upper side of the guide cavity 83, and the center of the left side of the screw 82 is fixedly connected to the output shaft of the right side of the second motor 81; the telescopic arm 10 is movably connected to the guide cavity 83 on the outer left side, and the upper left side of the telescopic arm 10 is provided with a threaded hole connected to the screw 82; the telescopic arm 10... The left side has an internal mounting cavity 84; the mounting cavity 84 has transverse grooves 85 at both the front and rear positions, and a guide wheel 810 is movably connected to the right side of the mounting cavity 84; the slider 88 is movably connected to the inner side of the corresponding grooves 85 at the front and rear exteriors, and a guide wheel 87 and a guide wheel 89 are movably connected to the left and right sides of the slider 88, respectively; one end of the rope 86 is fixedly connected to the upper left side of the mounting cavity 84, and the other end of the rope 86 is fixedly connected to the left side of the guide hole cavity 83; a guide wheel 811 is movably connected to the lower right side of the mounting cavity 84; the wire rope of the retracting mechanism 9 is connected to the retracting mechanism 9 in sequence through the guide wheel 810, the guide wheel 89, and the guide wheel 811.
[0026] Among them, motor 81 is a servo motor or a stepper motor.
[0027] like Figure 5As shown, the specific structure of the retracting mechanism 9 includes a linkage rod 91, a sliding hole 92, a rack 93, a transmission gear 94, a first transmission shaft 95, a spring 96, a first sprocket 97, a chain 98, a protective cover 99, a second sprocket 910, a second transmission shaft 911, a slot 912, a locking block 913, a hook 914, a fifth guide wheel 915, and a movable block 916. The sliding hole 92 is horizontally located inside the upper side of the telescopic arm 10. The transmission gear 94 is movably connected inside the lower right side of the sliding hole 92, and the first transmission shaft 95 is fixedly connected to the center of the transmission gear 94. The linkage rod 91 is movably connected inside the sliding hole 92. The rack 93 is fixedly connected to the lower right side of the linkage rod 91, and the rack 93 is connected to the transmission gear 94. A spring 96 is provided between the right side of the linkage rod 91 and the right side of the sliding hole 92. A sprocket is fixedly connected to the rear exterior of the first transmission shaft 95. 97; The movable block 916 is fixedly connected to the front and rear centers of the drive shaft 911, and the drive shaft 911 is movably connected to the front and rear holes opened inside the right side of the telescopic arm 10. In addition, the drive shaft 911 on the rear side is fixedly connected to the sprocket 910, and the sprocket 910 is connected to the drive shaft 97 on the rear side through the chain 98. The movable block 916 has a slot 912 in the center of the lower side, and the movable block 916 has a guide wheel 915 movably connected inside the upper left side. The drive shaft 97, the drive shaft 910, and the chain 98 are all located inside the protective cover 99, and the protective cover 99 is fixedly connected to the right rear side of the telescopic arm 10. The upper side of the locking block 913 is connected to the slot 912, and the bottom of the locking block 913 is provided with a hook 914. The wire rope of the retraction mechanism 9 is fixedly connected to the center of the upper side of the locking block 913 through the telescopic adjustment mechanism 8 and the guide wheel 915.
[0028] The slot 912 is a conical slot that matches the upper outer side of the block 913; the lifting mechanism 7 is a winch. The invention is used as follows: It features a simple and reasonable structure, low production cost, and convenient installation. During use, motor 21 (servo motor or stepper motor) is started, and its output shaft drives the drive gear 22 to rotate. The drive gear 22 meshes with the driven gear 23, thereby driving the rotating seat 24 to rotate internally in the center of the upper side of the base 1. Since the top of the rotating seat 24 is fixedly connected to the bottom of the support seat 3, the support seat 3 will rotate along with the rotating seat 24, causing the entire upper structure of the crane to rotate and adjust to a suitable working direction. During telescopic adjustment, motor 81 (servo motor or stepper motor) is turned on, and its right... The side output shaft drives the screw 82 to rotate on the upper side of the guide cavity 83. The left side of the telescopic arm 10 is externally connected to the inside of the guide cavity 83, and a threaded hole is provided on the upper left side to connect with the screw 82. Under the rotation of the screw 82, the telescopic arm 10 extends and retracts left and right along the guide cavity 83. During the extension and retraction process, one end of the rope 86 is fixedly connected to the upper left side of the mounting cavity 84, and the other end is fixedly connected to the left side of the guide cavity 83. Through the guiding and linkage of the guide wheel 1 87, guide wheel 2 89, guide wheel 3 810 and guide wheel 4 811, the length of the wire rope output does not change during the extension and retraction process, thereby ensuring stability during hoisting. For qualitative and reliable lifting, the hoisting mechanism 7 (winch) starts working, connected to the retraction mechanism 9 via a wire rope, to achieve the lifting and lowering action of the hook 914 to meet the height requirements of the hoisted goods. When retraction is required, the hoisting mechanism 7 is first activated to retract the wire rope. Here, the conical groove 912 in the lower center of the movable block 916 matches the upper outer side of the locking block 913, allowing the locking block 913 to be gradually locked into the groove 912, thus retracting and fixing the hook 914. Then, the motor 81 is activated to retract the telescopic boom 10. When the telescopic boom 10 retracts, the linkage rod 91 will contact the right side of the movable boom 6, thus enabling the hook 914 to be retracted and fixed. The rack 93 moves to the right inside the sliding hole 92, meshing with the transmission gear 94, causing the transmission gear 94 to rotate, which in turn drives the transmission shaft 95 to rotate. The sprocket 97 behind the transmission shaft 95 rotates, driving the sprocket 910 to rotate via the chain 98, causing the movable block 916 to rotate clockwise and retract, thus preventing erratic movement in strong winds. The spring 96 provides a reset function, providing elastic force to the linkage rod 91 after the hook is lowered. In addition, in extreme weather conditions, the movable boom 6 can be retracted as a whole by shortening the hydraulic cylinder 4, thereby improving the service life of the crane.
[0029] The control method of this invention is either manual start-up or control through existing automation technology. The wiring diagram of the power element and the supply of power are common knowledge in the field. Furthermore, since this invention is mainly used to protect mechanical devices, the control method and wiring layout will not be explained in detail here.
[0030] In the description of the invention, it should be understood that the terms "coaxial," "bottom," "one end," "top," "middle," "other end," "upper," "side," "top," "inner," "front," "center," "both ends," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.
[0031] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0032] The foregoing has shown and described the basic principles, main features, and advantages of the invention. Those skilled in the art should understand that the invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications may be made to the invention without departing from its spirit and scope. All such changes and modifications fall within the scope of the invention as claimed, which is defined by the appended claims and their equivalents.
Claims
1. An automatic hook-retracting device for a marine crane, characterized in that: It includes a base (1), a rotating mechanism (2), a support base (3), a hydraulic cylinder (4), a connecting block (5), a movable arm (6), a lifting mechanism (7), a telescopic adjustment mechanism (8), a retracting mechanism (9), and a telescopic arm (10). The base (1) has a rotating mechanism (2) inside its upper side, and a support seat (3) is fixedly connected to the upper side of the rotating mechanism (2). The lower side of the oil cylinder (4) is movably connected to the center of the left side inside the support base (3), and the end of the piston rod on the upper side of the oil cylinder (4) is hinged to the lower right side of the movable arm (6); The connecting block (5) is fixedly connected to the lower side of the movable arm (6), and the lower side of the connecting block (5) is movably connected to the upper right side inside the support base (3); The telescopic adjustment mechanism (8) is located on the left side inside the movable arm (6), and the telescopic adjustment mechanism (8) is located on the right side inside the left side of the telescopic arm (10); The telescopic arm (10) is provided with a retraction mechanism (9) on the right side. The lifting mechanism (7) is fixedly connected to the left end of the movable arm (6), and the right side of the lifting mechanism (7) is connected to the retracting mechanism (9) through the telescopic adjustment mechanism (8).
2. The automatic hook-retracting device for marine cranes according to claim 1, characterized in that: The specific structure of the rotating mechanism (2) includes a motor (21), a driving gear (22), a driven gear (23), and a rotating base (24). The base (1) is fixedly connected to a motor (21) on the lower left side, and a drive gear (22) is fixedly connected to the output shaft on the upper side of the motor (21). The lower side of the rotating seat (24) is movably connected to the upper center of the base (1). A driven gear (23) is fixedly connected to the lower side of the rotating seat (24), and the driven gear (23) is connected to the driving gear (22). The top of the rotating seat (24) is fixedly connected to the bottom of the support seat (3).
3. The automatic hook-retracting device for marine cranes according to claim 2, characterized in that: The motor (21) is a servo motor or a stepper motor.
4. The automatic hook-retracting device for marine cranes according to claim 1, characterized in that: The specific structure of the telescopic adjustment mechanism (8) includes a second motor (81), a screw (82), a guide hole cavity (83), a mounting cavity (84), a slide (85), a rope (86), a first guide wheel (87), a slider (88), a second guide wheel (89), a third guide wheel (810), and a fourth guide wheel (811). The second motor (81) is fixedly connected to the inside of the upper left side of the movable arm (6); The guide hole cavity (83) is located inside the right side of the movable arm (6); The screw (82) is movably connected to the upper side of the guide hole cavity (83), and the left center of the screw (82) is fixedly connected to the right output shaft of the second motor (81); The telescopic arm (10) is externally connected to the guide hole cavity (83) on the left side. The upper left side of the telescopic arm (10) is connected to the screw (82) through a threaded hole. The telescopic arm (10) is internally provided with an installation cavity (84) on the left side. The mounting cavity (84) is provided with transverse sliding grooves (85) at both the front and rear positions, and a guide wheel (810) is movably connected to the right side of the mounting cavity (84). The slider (88) is movably connected to the inner side of the corresponding slide groove (85) at the front and rear exteriors respectively, and the slider (88) is movably connected to the inner side of the left and right sides respectively by guide wheel one (87) and guide wheel two (89). One end of the rope (86) is fixedly connected to the upper left side of the mounting cavity (84), and the other end of the rope (86) is fixedly connected to the left side of the guide hole cavity (83); The guide wheel four (811) is movably connected to the lower right side of the mounting cavity (84); The wire rope of the retracting mechanism (9) is connected to the retracting mechanism (9) in sequence through guide wheel three (810), guide wheel two (89) and guide wheel four (811).
5. The automatic hook-retracting device for marine cranes according to claim 4, characterized in that: The second motor (81) is a servo motor or a stepper motor.
6. The automatic hook-retracting device for marine cranes according to claim 1, characterized in that: The specific structure of the retracting mechanism (9) includes a linkage rod (91), a sliding hole (92), a rack (93), a transmission gear (94), a first transmission shaft (95), a spring (96), a first sprocket (97), a chain (98), a protective cover (99), a second sprocket (910), a second transmission shaft (911), a slot (912), a locking block (913), a hook (914), a fifth guide wheel (915), and a movable block (916). The sliding hole (92) is horizontally located inside the upper side of the telescopic arm (10). A transmission gear (94) is movably connected inside the lower right side of the sliding hole (92), and a transmission shaft (95) is fixedly connected inside the center of the transmission gear (94). The linkage rod (91) is movably connected inside the sliding hole (92). A rack (93) is fixedly connected to the lower right side of the linkage rod (91), and the rack (93) is connected to the transmission gear (94). A spring (96) is provided between the right side of the linkage rod (91) and the right side of the sliding hole (92). A sprocket (97) is fixedly connected to the rear external side of the drive shaft (95). The movable block (916) is fixedly connected to the front and rear center of the transmission shaft two (911), and the transmission shaft two (911) is movably connected to the front and rear holes opened inside the right side of the telescopic arm (10). In addition, the transmission shaft two (911) on the rear side is fixedly connected to the outside of the transmission shaft two (911), and the transmission shaft two (910) is connected to the transmission shaft one (97) through the chain (98). The movable block (916) has a slot (912) opened in the center of the lower side, and the movable block (916) has a guide wheel five (915) movably connected inside the upper left side. The first sprocket (97), the second sprocket (910) and the chain (98) are all located inside the protective cover (99), and the protective cover (99) is fixedly connected to the outside of the right rear side of the telescopic arm (10); The upper side of the card block (913) is connected to the card slot (912), and the bottom of the card block (913) is provided with a hook (914). The wire rope of the retracting mechanism (9) is fixedly connected to the upper center of the locking block (913) through the telescopic adjustment mechanism (8) and the guide wheel five (915).
7. The automatic hook-retracting device for marine cranes according to claim 6, characterized in that: The slot (912) is a tapered slot and matches the upper outer side of the card block (913).
8. The automatic hook-retracting device for marine cranes according to claim 1, characterized in that: The lifting mechanism (7) is a winch.