Marine variable frequency electric crane

Abstract

This invention relates to the field of crane technology, specifically a marine variable frequency electric crane; it includes a base; a lifting arm is rotatably connected to the upper end of the base; a hydraulic cylinder is provided between the base and the lifting arm; one end of the hydraulic cylinder is hinged to the base, and the other end is hinged to the lifting arm; this invention, by setting a constraint frame, allows the constraint frame to support the elongated steel cable through a constraint rod during the descent of the constraint frame pushed by the electro-hydraulic actuator, reducing the free length of the steel cable and thus reducing the distance the steel cable can swing, greatly reducing the amplitude of cargo swing, thereby reducing the occurrence of collisions and reducing the difficulty of precise cargo positioning. In addition, the reduced amplitude of cargo swing reduces the disturbance torque generated by cargo inertia, thereby reducing the ship's roll amplitude, reducing the ship's heel or trim amplitude, making the ship's center of gravity more stable, and thus ensuring the navigation safety of the ship and the stability of the crane equipment itself.

Description

Technical Field

[0001] This invention relates to the field of crane technology, specifically a marine variable frequency electric crane. Background Technology

[0002] A crane is a multi-action lifting machine that can vertically lift and horizontally move heavy objects within a certain range. It is widely used in construction sites, factories, ports, warehouses and other places. In response to the special needs of the marine operation environment, marine cranes have been developed specifically for ships and offshore platforms. They can stably and safely complete the lifting operations of goods or equipment under complex sea conditions.

[0003] Due to strong winds at sea, cargo suspended on the hook by a marine crane is easily affected by the lateral or longitudinal forces of the wind during lifting operations, causing it to sway or even rotate. This uncontrolled swaying not only increases the difficulty of precise cargo positioning but also can lead to collisions, posing safety hazards to operators. Furthermore, the inertial swaying of the cargo generates disturbance torque that exacerbates the ship's rolling motion, leading to increased heeling or trimming. This not only increases the difficulty of controlling the lifting operation but also poses a serious threat to the ship's navigational safety and the stability of the crane itself. In view of this, in order to overcome the above-mentioned technical problems, the present invention proposes a marine variable frequency electric crane, which solves the above-mentioned technical problems. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention proposes a marine variable frequency electric crane. By setting up a constraint frame, the constraint frame supports the elongated steel cable through constraint rods during the descent of the electro-hydraulic pusher, reducing the free length of the steel cable and thus the distance it can swing. This significantly reduces the amplitude of cargo swing, thereby reducing the occurrence of collisions and simplifying the precise positioning of the cargo. Furthermore, the reduced cargo swing amplitude decreases the disturbance torque generated by cargo inertia, further reducing the ship's roll and heel amplitude, making the ship's center of gravity more stable, and ultimately ensuring the ship's navigation safety and the stability of the crane itself.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows: A marine variable frequency electric crane, comprising a base; a lifting arm rotatably connected to the upper end of the base; a hydraulic cylinder disposed between the base and the lifting arm; one end of the hydraulic cylinder hinged to the base, and the other end hinged to the lifting arm; a hook installed at the end of the lifting arm away from the base; a winding mechanism installed on one side of the base; and the hook connected to the winding mechanism via a steel cable. A constraint frame is provided above the hook; a mounting bracket is fixedly connected to the end of the lifting arm away from the base; the constraint frame and the mounting bracket are in sliding contact; an electro-hydraulic actuator is fixedly installed inside the mounting bracket; the electro-hydraulic actuator is used to push the constraint frame down; a constraint rod is rotatably connected inside the constraint frame; a locking rod is rotatably connected to one side of the constraint rod. The inner wall of the lifting boom is provided with a sliding groove; a hydraulic push rod is provided in the sliding groove; the end of the hydraulic push rod near the base is rotatably connected to the sliding groove through a hinge rod; the end of the hydraulic push rod away from the base is connected to the constraint frame through a snap-fit ​​unit; a servo motor is fixedly connected to the upper end of the base; the hydraulic push rod and the output end of the servo motor are connected by a steel wire rope.

[0006] Preferably, the locking unit includes a locking rod; a locking groove is provided at the end of the hydraulic push rod away from the base; one end of the locking rod is directly opposite the locking groove, and the other end is hinged to the constraint frame; a cylindrical groove is provided on the surface of the locking rod; a locking pin is slidably connected in the cylindrical groove; a circular groove is provided on the groove wall of the locking groove, which is directly opposite the cylindrical groove; a pushing unit is installed in the constraint frame; the pushing unit is used to push the locking pin out of the cylindrical groove.

[0007] Preferably, the pushing unit includes a pushing rod; a slot is provided inside the constraint frame; the pushing rod is slidably and sealed within the slot; the pushing rod is connected to the bottom of the slot via a support spring; the slot and the cylindrical groove are connected via an oil pipe; the cross-sectional shape of the pushing rod is set to I-shape; a push plate is fixedly connected to the lower end of the electro-hydraulic push rod; grippers are rotatably connected to both sides of the push plate; the grippers are rotatably connected to the push plate via torsion springs; and an inclined plate fixedly connected to the mounting bracket is provided above the grippers.

[0008] Preferably, the inner wall of the constraint frame has a groove; a bracket is slidably connected in the groove; a cleaning cotton is rotatably connected to the end of the bracket away from the groove; a strip groove and an oil passage are formed in the constraint frame; a strip plate is slidably connected in the strip groove; the strip plate and the bottom of the strip groove are connected by a fixed spring; one end of the oil passage is connected to the strip groove, and the other end is connected to the groove.

[0009] Preferably, a rotating rod is rotatably connected within the constraint frame; the rotating rod and the constraint rod are connected by a belt drive; one end of the rotating rod has a square groove communicating with the groove; a square block is slidably and sealingly connected within the square groove; and the end of the cleaning cotton near the rotating rod has a connecting groove directly opposite the square block.

[0010] Preferably, a squeezing rod is provided below the cleaning cotton; the squeezing rod is rotatably connected to the constraint frame; the squeezing rod is made of PTFE material.

[0011] Preferably, a raised strip is fixedly attached to the surface of the constraint rod; the raised strip is made of fluororubber material.

[0012] The beneficial effects of this invention are as follows: This invention, by setting a constraint frame, allows the constraint frame to support the elongated steel cable through a constraint rod during the descent of the electro-hydraulic actuator. This reduces the free length of the steel cable, decreasing the distance it can swing and significantly reducing the amplitude of cargo swing. This reduces the occurrence of collisions and simplifies the difficulty of precise cargo positioning. Furthermore, the reduced cargo swing amplitude decreases the disturbance torque generated by cargo inertia, thereby reducing the ship's roll amplitude and the magnitude of heel or trim. This makes the ship's center of gravity more stable, ensuring the safety of navigation and the stability of the crane equipment itself.

[0013] The present invention supports the constraint frame by using a hydraulic push rod instead of a metal rod because when the boom is fully extended, the hydraulic push rod, installed at the second boom section, causes the constraint frame connected to the hydraulic push rod to pull the steel cable closer to the second boom section via the constraint rod and clamp rod. This reduces the working radius of the boom for lifting goods. At this time, by simply controlling the extension of the hydraulic push rod, the hydraulic push rod can be made to push the constraint frame away from the second boom section, thereby increasing the working radius of the boom for lifting goods and improving the practicality of the present invention. Attached Figure Description

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0015] Figure 1 This is a perspective view of the present invention; Figure 2 This is a schematic diagram of the mounting bracket used in this invention; Figure 3 yes Figure 2 Enlarged view of point A in the middle; Figure 4 yes Figure 2 Enlarged view of point B in the middle; Figure 5 This is a schematic diagram of the constraint frame used in this invention; Figure 6 yes Figure 5 Enlarged view of point C in the middle; In the diagram: 1. Base; 11. Lifting boom; 12. Hydraulic cylinder; 13. Hook; 14. Winding mechanism; 141. Steel cable; 15. Mounting bracket; 151. Electro-hydraulic actuator; 152. Push plate; 153. Gripper; 154. Inclined plate; 16. Servo motor; 161. Steel wire rope; 17. Slide groove; 171. Hydraulic actuator; 172. Slot; 173. Circular groove; 2. Constraint frame; 21. Constraint rod; 211. Locking rod; 212. Protrusion 22. Strip; 221. Snap-fit ​​rod; 222. Columnar groove; 222. Snap-fit ​​post; 23. Slot; 231. Push rod; 232. Support spring; 233. Oil pipe; 24. Groove; 241. Bracket; 242. Cleaning cotton; 243. Connecting groove; 25. Strip groove; 251. Oil passage; 252. Strip plate; 253. Fixing spring; 26. Rotating rod; 261. Belt; 262. Square groove; 263. Square block; 27. Extrusion rod. Detailed Implementation

[0016] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0017] like Figures 1 to 6 As shown, the present invention discloses a marine variable frequency electric crane, comprising a base 1; a lifting arm 11 is rotatably connected to the upper end of the base 1; a hydraulic cylinder 12 is disposed between the base 1 and the lifting arm 11; one end of the hydraulic cylinder 12 is hinged to the base 1, and the other end is hinged to the lifting arm 11; a hook 13 is installed at the end of the lifting arm 11 away from the base 1; a winding mechanism 14 is installed on one side of the base 1; the hook 13 is connected to the winding mechanism 14 via a steel cable 141. A constraint frame 2 is provided above the hook 13; a mounting bracket 15 is fixedly connected to one end of the lifting arm 11 away from the base 1; the constraint frame 2 is in sliding contact with the mounting bracket 15; an electro-hydraulic push rod 151 is fixedly installed inside the mounting bracket 15; the electro-hydraulic push rod 151 is used to push the constraint frame 2 down; a constraint rod 21 is rotatably connected inside the constraint frame 2; a locking rod 211 is rotatably connected to one side of the constraint rod 21. The inner wall of the lifting boom 11 is provided with a sliding groove 17; a hydraulic push rod 171 is provided in the sliding groove 17; the end of the hydraulic push rod 171 near the base 1 is rotatably connected to the sliding groove 17 through a hinge rod; the end of the hydraulic push rod 171 away from the base 1 is connected to the constraint frame 2 through a snap-fit ​​unit; a servo motor 16 is fixedly connected to the upper end of the base 1; the hydraulic push rod 171 and the output end of the servo motor 16 are connected by a steel wire rope 161.

[0018] In one embodiment of the present invention, the snap-fit ​​unit includes a snap-fit ​​rod 22; a snap-fit ​​groove 172 is provided at one end of the hydraulic push rod 171 away from the base 1; one end of the snap-fit ​​rod 22 is directly opposite the snap-fit ​​groove 172, and the other end is hinged to the constraint frame 2; a cylindrical groove 221 is provided on the surface of the snap-fit ​​rod 22; a snap-fit ​​post 222 is slidably connected in the cylindrical groove 221; a circular groove 173 is provided on the groove wall of the snap-fit ​​groove 172, which is directly opposite to the cylindrical groove 221; a pushing unit is installed in the constraint frame 2; the pushing unit is used to push the snap-fit ​​post 222 out of the cylindrical groove 221.

[0019] In one embodiment of the present invention, the pushing unit includes a pushing rod 231; a slot 23 is provided inside the constraint frame 2; the pushing rod 231 is slidably and sealingly connected in the slot 23; the pushing rod 231 is connected to the bottom of the slot 23 through a support spring 232; the slot 23 and the cylindrical groove 221 are connected through an oil pipe 233; the cross-sectional shape of the pushing rod 231 is set to I-shape; a push plate 152 is fixedly connected to the lower end of the electro-hydraulic push rod 151; grippers 153 are rotatably connected to both sides of the push plate 152; the grippers 153 are rotatably connected to the push plate 152 through torsion springs; an inclined plate 154 fixedly connected to the mounting bracket 15 is provided above the grippers 153.

[0020] During operation, due to strong winds at sea, cargo suspended on hook 13 is easily affected by the lateral or longitudinal forces of the wind, causing it to sway or even rotate. This uncontrolled swaying not only increases the difficulty of accurately positioning the cargo but also causes collisions, posing safety hazards to the operators. In addition, the disturbance torque generated by the inertial swaying of the cargo will exacerbate the swaying of the ship, leading to an increase in the magnitude of the ship's heel or trim. This not only increases the difficulty of controlling the lifting operation but also poses a serious threat to the navigation safety of the ship and the stability of the crane equipment itself.

[0021] To address this, the present invention sets up a constraint frame 2. During the process of the electro-hydraulic actuator 151 pushing the constraint frame 2 to descend, the constraint frame 2 supports the elongated steel cable 141 through the constraint rod 21, reducing the free length of the steel cable 141. This reduces the distance the steel cable 141 can swing, greatly reducing the amplitude of cargo swing, thereby reducing the occurrence of collisions and simplifying the precise positioning of cargo. In addition, the reduced amplitude of cargo swing reduces the disturbance torque generated by cargo inertia, thereby reducing the ship's roll amplitude and the amplitude of ship heel or trim, making the ship's center of gravity more stable, thus ensuring the navigation safety of the ship and the stability of the crane equipment itself.

[0022] The free length of the steel cable 141 refers to the length from the crane boom to the hook 13. The longer the free length of the steel cable 141, the greater its swing amplitude under the action of external forces (such as wind force, the swing of the load, etc.). When the crane lifts or lowers the load, the free length of the steel cable 141 will change. Especially when lowering the load, the steel cable 141 is released, and its length increases. The hook 13 and the load are subjected to wind force and will experience greater swing, leading to increased instability of the load. At this time, the user needs to control the extension of the electro-hydraulic actuator 151. Since the jaw 153 clamps the upper end of the push rod 231 in the initial state, during the descent of the electro-hydraulic actuator 151, the electro-hydraulic actuator 151 will push the push plate 152 fixed at the lower end to descend continuously. At this time, the push rod 231 descends under the action of gravity, causing the push rod 231 to drive the constraint that is slidably connected to it. As the frame 2 descends synchronously, a constraint rod 21 is installed inside the constraint frame 2. The steel cable 141, located between the hook 13 and the boom 11, passes between the constraint rod 21 and the clamping rod 211. During the descent of the constraint frame 2, the constraint frame 2 will drive the constraint rod 21 and the clamping rod 211 to descend synchronously along the steel cable 141. When the wind blows the goods, the goods will cause the steel cable 141 to sway. However, because the constraint rod 21 and the clamping rod 211 inside the constraint frame 2 clamp and limit the steel cable 141, the distance that the goods can swing laterally or longitudinally is only the distance between the hook 13 and the constraint frame 2. As the constraint frame 2 descends, the length of the steel cable 141 between the constraint frame 2 and the hook 13 is shortened, thereby reducing the free length of the steel cable 141 and reducing the distance that the steel cable 141 can swing. This greatly reduces the amplitude of the goods' swing, thereby reducing the occurrence of collisions and improving the accuracy of goods placement and positioning.

[0023] Because the length of the electro-hydraulic actuator 151 is fixed, when the marine crane operates at a high altitude (large distance between the hook 13 and the sea surface), the distance by which the electro-hydraulic actuator 151 pushes the constraint frame 2 downward is small. This results in a smaller reduction in the free length of the steel cable 141, and a smaller change in the swing amplitude of the steel cable 141. To further reduce the free length of the steel cable 141 and improve the accuracy of cargo positioning, this invention sets up a hydraulic actuator 171. Before lifting the cargo, the gripper 153 of the electro-hydraulic actuator 151 pulls the push rod 231 upward, allowing the push rod 231 to... The support spring 232 pulls the constraint frame 2 upward until it engages with the mounting bracket 15. At this point, the hydraulic push rod 171 and the engaging rod 22 are aligned. The hydraulic push rod 171 is extended, causing the end of the hydraulic push rod 171 with the slot 172 to continuously approach the engaging rod 22 until the engaging rod 22 is inserted into the slot 172. At this point, the locking post 222 and the circular groove 173 are aligned. The electro-hydraulic push rod 151 is then pulled upward by the push rod 231. Because the constraint frame 2 is blocked by the mounting bracket 15, it stops rising, causing the electro-hydraulic push rod 151 to continue pulling the push rod 231. Extending from slot 23, the push rod 231 further stretches the support spring 232 until the gripper 153 contacts the inclined plate 154. Both grippers 153, blocked by the upper inclined plate 154, overcome the torsion of the torsion spring and rotate towards each other. This causes the ends of the grippers 153 holding the push rod 231 to rotate away from each other, releasing the constraint rod 21. At this point, the push rod 231, pulled by the restoring force of the support spring 232, moves into the slot 23, causing the hydraulic oil in the slot 23 to be compressed by the push rod 231 and flow through the oil pipe. 233 enters the cylindrical groove 221; causing the locking pin 222 in the cylindrical groove 221 to extend out of the cylindrical groove 221 and insert into the circular groove 173 under the push of hydraulic oil. At this time, the hydraulic push rod 171 is connected to the constraint frame 2 through the locking rod 22. Since the gripper 153 is separated from the push rod 231, the electro-hydraulic push rod 151 no longer clamps and lifts the constraint frame 2 through the gripper 153. Therefore, the constraint frame 2 will slide down along the steel cable 141 under its own weight. Since the hydraulic push rod 171 is fixedly connected to the locking rod 22, the constraint frame 2 will not fall due to the traction of the hydraulic push rod 171.

[0024] The lifting boom 11 is configured as a three-section boom. A hydraulic push rod 171 is connected to the lower end of the second section of the boom 11. When the boom 11 extends and moves the hook 13 above the cargo, the hydraulic push rod 171 extends out of the first section under the action of the second section. At this time, the servo motor 16 releases the wire rope 161, so that the hydraulic push rod 171 is no longer pulled by the wire rope 161. Under its own weight, the hydraulic push rod 171 rotates downward along its hinged end. Simultaneously, the hydraulic... Push rod 171 drives constraint frame 2 to slide downward along steel cable 141 via snap rod 22 until the free length of steel cable 141 between constraint frame 2 and hook 13 reaches the specified length. Then, control servo motor 16 to stop rotating. At this time, hydraulic push rod 171 no longer rotates downward. Then, use hook 13 to connect the cargo and control winding mechanism 14 to wind up steel cable 141, so that the cargo can be lifted until hook 13 contacts the lower end face of constraint frame 2. At this time, the height of the cargo is the height between constraint frame 2 and ship plate.

[0025] The reason for using a hydraulic push rod 171 to support the constraint frame 2, instead of a non-metallic rod, is that the hydraulic push rod 171 can extend. When the third boom extends, since the hydraulic push rod 171 is installed at the second boom, the constraint frame 2 connected to the hydraulic push rod 171 will pull the steel cable 141 closer to the second boom. This reduces the working radius of the lifting boom 11 for hoisting goods. At this time, by controlling the extension of the hydraulic push rod 171, the hydraulic push rod 171 can be pushed away from the second boom, thereby increasing the working radius of the lifting boom 11 for hoisting goods and improving the practicality of the invention.

[0026] In one embodiment of the present invention, a groove 24 is provided on the inner wall of the constraint frame 2; a bracket 241 is slidably connected in the groove 24; a cleaning cotton 242 is rotatably connected to one end of the bracket 241 away from the groove 24; a strip groove 25 and an oil passage 251 are provided in the constraint frame 2; a strip plate 252 is slidably connected in the strip groove 25; the strip plate 252 and the bottom of the strip groove 25 are connected by a fixing spring 253; one end of the oil passage 251 communicates with the strip groove 25 and the other end communicates with the groove 24.

[0027] In one embodiment of the present invention, a rotating rod 26 is rotatably connected inside the constraint frame 2; the rotating rod 26 and the constraint rod 21 are connected by belt drive via a belt 261; one end of the rotating rod 26 has a square groove 262 communicating with the groove 24; a square block 263 is slidably and sealingly connected inside the square groove 262; the cleaning cotton 242 has a connecting groove 243 at the end near the rotating rod 26 that is directly opposite the square block 263.

[0028] In one embodiment of the present invention, a squeezing rod 27 is provided below the cleaning cotton 242; the squeezing rod 27 is rotatably connected to the constraint frame 2; the squeezing rod 27 is made of PTFE material.

[0029] In one embodiment of the present invention, a protrusion 212 is fixedly connected to the surface of the constraint rod 21; the protrusion 212 is made of fluororubber material.

[0030] When marine cranes perform tasks such as cargo transportation between ships, replenishment at sea, and deployment and retrieval of underwater equipment, seawater inevitably gets on the steel cable 141. Especially during the deployment and retrieval of underwater equipment, the crane's steel cable 141 needs to lift the equipment into or out of seawater, and part of the steel cable 141 will inevitably be directly immersed in seawater, leaving a large amount of seawater residue on the steel cable 141. Seawater is a highly corrosive liquid with a high salt content, which will accelerate the corrosion of the steel cable 141 and shorten its service life.

[0031] In this invention, a cleaning cotton 242 is provided so that during the winding and unwinding process of the winding mechanism 14, the steel cable 141 will roll into contact with the cleaning cotton 242, allowing the cleaning cotton 242 to absorb the seawater on the surface of the steel cable 141. This reduces the amount of seawater residue on the surface of the steel cable 141, reduces the corrosion caused by seawater to the steel cable 141, and improves the service life of the steel cable 141.

[0032] As the electro-hydraulic actuator 151 pulls the constraint frame 2 upward, the constraint frame 2 will cause the strip plate 252 to continuously approach the mounting bracket 15 until the strip plate 252 contacts the mounting bracket 15. This causes the strip plate 252 to be blocked by the mounting bracket 15, squeezing the fixing spring 253 into the strip groove 25. This causes the hydraulic oil in the groove 24 to flow back into the strip groove 25, causing the bracket 241 to be drawn into the groove 24 by the negative pressure. When the constraint frame 2 contacts the mounting bracket 15, at this time... The hydraulic push rod 171 pulls the push rod 231 through the gripper 153 to further stretch the support spring 232 out of the slot 23. At this time, the gripper 153 contacts the inclined plate 154, causing the gripper 153 to rotate towards each other due to the obstruction of the inclined plate 154. At this time, the push rod 231 enters the slot 23 under the pull of the support spring 232, allowing the hydraulic oil in the slot 23 to enter the cylindrical groove 221. At this time, the hydraulic push rod 171 is connected to the locking rod 22 through the locking pin 222 in the cylindrical groove 221.

[0033] When the constraint frame 2 separates from the mounting bracket 15, the strip plate 252 is no longer blocked by the mounting bracket 15, allowing the strip plate 252 to extend out of the strip groove 25 under the restoring force of the fixing spring 253. This causes the strip plate 252 to squeeze the hydraulic oil in the strip groove 25 into the groove 24, causing the bracket 241 in the groove 24 to push the cleaning cotton 242 out of the groove 24, making the cleaning cotton 242 contact the steel cable 141. During the deployment and retrieval of the underwater equipment, the winding mechanism 14 releases and winds the steel cable 141. The steel cable 141 will slide into contact with the constraint rod 21. To reduce the sliding friction between the steel cable 141 and the constraint rod 21 and avoid damage to the constraint rod 21 due to sliding friction, the constraint rod 21 is rotatably connected to the constraint frame 2, and the constraint rod 21... The surface is fixed with a protrusion 212, which allows the steel cable 141 to contact only the protrusion 212 on the surface of the constraint rod 21. The friction between the steel cable 141 and the protrusion 212 drives the protrusion 212 to rotate the constraint rod 21, thereby changing the sliding friction between the constraint rod 21 and the steel cable 141 to rolling friction. This greatly reduces the wear caused by the steel cable 141 on the constraint rod 21 and improves the service life of the constraint rod 21. By making the protrusion 212 with fluororubber, the protrusion 212 has a good coefficient of friction and wear resistance. This ensures that the steel cable 141 can stably drive the constraint rod 21 to rotate through the friction between it and the protrusion 212, and also reduces the wear caused by the steel cable 141 on the protrusion 212, thus improving the service life of the protrusion 212.

[0034] During the rotation of the constraint rod 21, the constraint rod 21 can drive the rotating rod 26 connected to it to rotate via the belt 261. When the strip plate 252 squeezes the hydraulic oil in the strip groove 25 into the groove 24, the bracket 241 in the groove 24 pushes the cleaning cotton 242 out of the groove 24. Then, the connecting groove 243 on one side of the rotating shaft of the cleaning cotton 242 is aligned with the square groove 262 at one end of the rotating rod 26. As the strip plate 252 squeezes the hydraulic oil in the strip groove 25 into the groove 24, the hydraulic oil in the groove 24 flows into the square groove 262 connected to the groove 24. This causes the hydraulic oil entering the square groove 262 to push the square block 263 out of the square groove 262 and into the connecting groove 243, allowing the rotating rod 26 to connect with the square block 263. The cleaning cotton 242 is connected so that when the constraint rod 21 drives the rotating rod 26 to rotate via the belt 261, the rotating rod 26 can drive the cleaning cotton 242 to rotate via the square block 263. Since the constraint rod 21, which is pushed by the steel cable 141, is connected to the rotating rod 26 via the belt 261, the rotation direction of the constraint rod 21 is the same as the rotation direction of the rotating rod 26. Therefore, the direction in which the rotating rod 26 drives the cleaning cotton 242 to rotate via the square block 263 is the same as the rotation direction of the constraint rod 21. This makes the rotation direction of the cleaning cotton 242 the same as the direction in which the steel cable 141 moves, so that the cleaning cotton 242 can roll into contact with the steel cable 141, thereby reducing the friction between the cleaning cotton 242 and the steel cable 141 and improving the service life of the cleaning cotton 242.

[0035] By setting up the squeezing rod 27, the squeezing rod 27 rolls into contact with the cleaning cotton 242, causing the cleaning cotton 242 to first rotate to the steel cable 141 to absorb seawater from the surface of the steel cable 141. Then, the part of the cleaning cotton 242 that has absorbed seawater rotates to the squeezing rod 27, causing the squeezing rod 27 to squeeze the part of the cleaning cotton 242 that has absorbed seawater, thus squeezing out the seawater absorbed by the cleaning cotton 242. This ensures the drying effect of the cleaning cotton 242, improves the absorption effect of the cleaning cotton 242 on the surface of the steel cable 141, further reduces the residue of seawater on the surface of the steel cable 141, reduces the corrosion caused by seawater to the steel cable 141, and improves the service life of the steel cable 141.

[0036] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present 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 can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A marine variable frequency electric crane, comprising a base (1); a lifting arm (11) is rotatably connected to the upper end of the base (1); a hydraulic cylinder (12) is provided between the base (1) and the lifting arm (11); one end of the hydraulic cylinder (12) is hinged to the base (1), and the other end is hinged to the lifting arm (11); a hook (13) is installed at the end of the lifting arm (11) away from the base (1); a winding mechanism (14) is installed on one side of the base (1); the hook (13) is connected to the winding mechanism (14) via a steel cable (141), characterized in that: A constraint frame (2) is provided above the hook (13); a mounting bracket (15) is fixedly connected to one end of the lifting arm (11) away from the base (1); the constraint frame (2) and the mounting bracket (15) are in sliding contact; an electro-hydraulic push rod (151) is fixedly installed inside the mounting bracket (15); the electro-hydraulic push rod (151) is used to push the constraint frame (2) down; a constraint rod (21) is rotatably connected inside the constraint frame (2); a clamping rod (211) is rotatably connected to one side of the constraint rod (21); The inner wall of the lifting arm (11) is provided with a sliding groove (17); a hydraulic push rod (171) is provided in the sliding groove (17); the end of the hydraulic push rod (171) near the base (1) is rotatably connected in the sliding groove (17) through a hinge rod; the end of the hydraulic push rod (171) away from the base (1) is connected to the constraint frame (2) through a snap-fit ​​unit; a servo motor (16) is fixedly connected to the upper end of the base (1); the hydraulic push rod (171) and the output end of the servo motor (16) are connected by a steel wire rope (161).

2. The marine variable frequency electric crane according to claim 1, characterized in that: The snap-fit ​​unit includes a snap-fit ​​rod (22); the hydraulic push rod (171) has a snap-fit ​​groove (172) at one end away from the base (1); one end of the snap-fit ​​rod (22) is directly opposite the snap-fit ​​groove (172), and the other end is hinged to the constraint frame (2); a cylindrical groove (221) is provided on the surface of the snap-fit ​​rod (22); a snap-fit ​​post (222) is slidably connected in the cylindrical groove (221); a circular groove (173) is provided on the groove wall of the snap-fit ​​groove (172) directly opposite the cylindrical groove (221); a pushing unit is installed in the constraint frame (2); the pushing unit is used to push the snap-fit ​​post (222) out of the cylindrical groove (221).

3. A marine variable frequency electric crane according to claim 2, characterized in that: The pushing unit includes a pushing rod (231); a slot (23) is provided inside the constraint frame (2); the pushing rod (231) is slidably and sealed in the slot (23); the pushing rod (231) is connected to the bottom of the slot (23) through a support spring (232); the slot (23) and the cylindrical groove (221) are connected through an oil pipe (233); the cross-sectional shape of the pushing rod (231) is set to I-shape; a push plate (152) is fixedly connected to the lower end of the electro-hydraulic push rod (151); grippers (153) are rotatably connected to both sides of the push plate (152); the grippers (153) are rotatably connected to the push plate (152) through a torsion spring; an inclined plate (154) fixedly connected to the mounting bracket (15) is provided above the grippers (153).

4. A marine variable frequency electric crane according to claim 3, characterized in that: The inner wall of the constraint frame (2) is provided with a groove (24); a bracket (241) is slidably connected in the groove (24); a cleaning cotton (242) is rotatably connected to one end of the bracket (241) away from the groove (24); a strip groove (25) and an oil passage (251) are provided in the constraint frame (2); a strip plate (252) is slidably connected in the strip groove (25); the strip plate (252) is connected to the bottom of the strip groove (25) by a fixing spring (253); one end of the oil passage (251) is connected to the strip groove (25), and the other end is connected to the groove (24).

5. A marine variable frequency electric crane according to claim 4, characterized in that: A rotating rod (26) is rotatably connected inside the constraint frame (2); the rotating rod (26) and the constraint rod (21) are connected by belt drive via a belt (261); a square groove (262) communicating with the groove (24) is opened at one end of the rotating rod (26); a square block (263) is slidably and sealed inside the square groove (262); a connecting groove (243) facing the square block (263) is opened at the end of the cleaning cotton (242) near the rotating rod (26).

6. A marine variable frequency electric crane according to claim 5, characterized in that: A squeezing rod (27) is provided below the cleaning cotton (242); the squeezing rod (27) is rotatably connected to the constraint frame (2); the squeezing rod (27) is made of PTFE material.

7. A marine variable frequency electric crane according to claim 6, characterized in that: The surface of the constraint rod (21) is fixed with a protrusion (212); the protrusion (212) is made of fluororubber material.

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