CN116081495A

CN116081495A - Bridge crane with protection function

Info

Publication number: CN116081495A
Application number: CN202310368845.5A
Authority: CN
Inventors: 李广超; 施晓玲; 李振敏; 李贯伍; 杨东方; 李飞; 张亚峰; 张鑫
Original assignee: Demarco Hoisting Machinery Co Ltd
Current assignee: Demarco Hoisting Machinery Co Ltd
Priority date: 2023-04-10
Filing date: 2023-04-10
Publication date: 2023-05-09
Anticipated expiration: 2043-04-10
Also published as: CN116081495B

Abstract

The invention relates to the technical field of bridge cranes, in particular to a bridge crane with a protection function. A bridge crane with a protection function comprises a bridge crane, a beam trolley, a pulley mechanism, a lifting hook mechanism, a cable mechanism and a rotating mechanism. The cable mechanism comprises a vertically arranged cable, the pulley mechanism comprises a pulley shell and a pulley, and a connecting plate is fixedly arranged at the lower end of the pulley shell. The pulley is rotatably disposed in the pulley housing about its own axis. The lifting hook mechanism comprises a lifting hook which is rotatably arranged on the connecting plate and is in friction contact with the connecting plate. The rotating mechanism is fixedly arranged on the beam trolley, and after the lifting hook lifts the heavy object, the rotating mechanism resets the cable mechanism and the pulley mechanism through the torsion cable before the heavy object is dismounted. The invention provides a bridge crane with a protection function, which solves the problem that the existing bridge crane is easy to cause safety accidents.

Description

Bridge crane with protection function

Technical Field

The invention relates to the technical field of bridge cranes, in particular to a bridge crane with a protection function.

Background

A crane is a common hoisting machine in industry, wherein a bridge crane is a crane that can handle goods in vertical direction and in lateral direction, and can replace manual handling of heavier goods or goods in higher positions. In the workshop, when a worker operates a crane to hoist the goods, the worker is required to constantly change the gesture of the goods due to complex environment in the workshop, and finally the goods are placed to a target position.

The chinese patent of the invention, issued to CN110844795B, provides an overload protection bridge crane which prevents the heavy objects from falling down when the crane is overloaded, but eventually when the load is placed at the target position, the hoisting portion is rotated after the load is removed because the attitude of the load is uncertain when the load is placed at the target position and the cable is twisted, which is very liable to cause injury to workers in the workshop.

Disclosure of Invention

The invention provides a bridge crane with a protection function, which solves the problem that the existing bridge crane is easy to cause safety accidents.

The bridge crane with the protection function adopts the following technical scheme: a bridge crane with a protection function comprises a bridge crane, a beam trolley, a pulley mechanism, a lifting hook mechanism, a cable mechanism and a rotating mechanism. The bridge crane is slidingly arranged on the ground, and the beam trolley is slidingly arranged on the bridge crane. The cable mechanism comprises a cable, one end of which is connected to the crossbeam trolley.

The pulley mechanism comprises a pulley shell and a pulley, and a connecting plate is fixedly arranged at the lower end of the pulley shell. The pulley can rotate around self axis and set up in the pulley shell, and the other end winding of hawser is connected with the crossbeam dolly behind a pulley, and during initial state, from down up, the projection line of pulley on the crossbeam dolly is the reference line. The lifting hook mechanism comprises a lifting hook which is rotatably arranged on the connecting plate and is in friction transmission fit with the connecting plate. The lifting hook is rotated, and the lifting hook drives the pulley mechanism to rotate through the connecting plate, so that an included angle is formed between a projection line and a reference line on the crossbeam trolley when the pulley is seen from bottom to top, and the mooring rope is twisted. The rotating mechanism is fixedly arranged on the beam trolley, and after the lifting hook lifts the heavy object, the rotating mechanism resets the cable mechanism and the pulley mechanism through the torsion cable before the heavy object is dismounted.

Further, at least one placement block is fixedly arranged on the pulley shell. The pulley is provided with two opposite conical surfaces, a ring groove for installing a cable is arranged between the two conical surfaces, and the cable can deviate to any one conical surface.

The bridge crane with the protection function further comprises a plurality of sensing mechanisms, wherein each sensing mechanism comprises a fixed block, a rotating rod, a rotating ball sleeve and an angle sensor. Each fixed block is fixedly arranged on one placing block, one end of the rotating rod can be horizontally and rotatably arranged on the fixed block, and the other end of the rotating rod is fixedly provided with a lantern ring. The rotating ball sleeve is arranged on the cable, and the rotating ball sleeve and the lantern ring can rotate relatively. In the initial state, the cable is positioned in the annular groove, and the projection of the rotating rod in the horizontal direction is perpendicular to the axis of the pulley shell. The angle sensor is arranged on the placing block, when the cable deviates to one of the conical surfaces, the cable drives the rotating rod to rotate, and the angle sensor is used for sensing the deflection angle between the projection of the rotating rod in the horizontal direction and the axis of the pulley shell.

Further, the bridge crane with the protection function further comprises an adjusting mechanism, wherein the adjusting mechanism comprises a magnetic baffle column, a limiting piece and a magnetic stop block. The magnetic baffle column is fixedly arranged on the connecting plate. The limiting piece is horizontally arranged and rotationally arranged at the upper end of the lifting hook around the axis of the limiting piece, and a channel is formed in the peripheral wall of the limiting piece. The magnetic stop block can be arranged in the channel in a sliding manner along the radial direction of the limiting piece. The magnetic force dog has first state and second state, and when magnetic force dog was in first state, magnetic force dog was in the locating part outward to with magnetism fender post contact, when magnetic force dog was in the second state, magnetic force dog was in the locating part, magnetic force dog and magnetism fender post break away from the contact.

Further, a small air cylinder is arranged in the limiting piece and used for controlling the magnetic force stop block to move along the radial direction of the limiting piece. The magnetic stop block and one side of the magnetic stop post, which are in contact with each other, are magnetic, and when the magnetic stop block is in a first state, the magnetic stop block and the magnetic stop post are attracted by magnetic force. The small cylinder controls the magnetic stop block to move towards the inside of the limiting piece, so that the magnetic stop block is separated from contact with the magnetic stop post.

Further, a small motor is arranged in the lifting hook, and an output shaft of the small motor is fixedly connected to the limiting piece.

Further, the bridge crane with the protection function further comprises a controller for receiving data of the angle sensor and transmitting the data to the small motor to rotate and enable the small cylinder to stretch and retract.

Further, the rotating mechanism comprises a connecting column, a mounting plate, a rotating frame, a large motor, a driven gear and a plurality of torsion bars. The upper end fixed connection of spliced pole is in the lower extreme of crossbeam dolly, and the mounting panel is fixed to be set up in the lower extreme of spliced pole. The rotating frame is rotatably arranged at the lower end of the mounting plate, the driven gear is horizontally arranged, and the driven gear is rotatably arranged on the rotating frame around the axis of the driven gear. The plurality of torsion bars are evenly arranged along the circumference of the driven gear, each torsion bar extends along the radial direction of the driven gear, one end of each torsion bar is fixedly connected to the rotating frame, and the other end of each torsion bar is used for propping against the mooring rope. The large motor is fixedly arranged on the mounting plate, and a driving gear meshed with the driven gear is fixedly arranged on an output shaft of the large motor.

Further, the connection post can be telescopic.

Further, a winch for adjusting the length of the cable is arranged in the crossbeam trolley.

Further, a plurality of travelling wheels are arranged on the beam trolley, and the travelling wheels are slidingly arranged on the bridge crane.

The beneficial effects of the invention are as follows: according to the bridge crane with the protection function, when a lifting hook lifts a heavy object, the lifting hook is rotated according to a specific working environment, the pulley mechanism is driven to rotate, and the mooring rope is twisted. Through setting up rotary mechanism, can increase the anti-torsion of hawser, after the lifting hook lifts up the heavy object, before unloading the heavy object, rotary mechanism resets hawser mechanism and pulley mechanism through reverse torsion hawser for the heavy object is transported and is accomplished and lift down the back, and the hawser is in initial condition, releases the torsion of hawser completely, has avoided the lifting hook to receive the effect of hawser torsion to rock, can not cause the injury to operating personnel.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained according to these drawings without inventive faculty for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a bridge crane with protection function according to an embodiment of the present invention;

FIG. 2 is an enlarged view of FIG. 1 at A;

FIG. 3 is an enlarged view at B in FIG. 1;

fig. 4 is a front view of a bridge crane with protection function according to another embodiment of the present invention;

FIG. 5 is an enlarged view at C in FIG. 4;

FIG. 6 is an enlarged view of FIG. 4 at D;

FIG. 7 is a cross-sectional view taken at E-E of FIG. 4;

FIG. 8 is a cross-sectional view taken at F-F in FIG. 4;

fig. 9 is an enlarged view at G in fig. 8.

In the figure: 100. a beam trolley; 110. a walking wheel; 200. a pulley mechanism; 210. pulley housing; 211. a pulley; 230. a connecting plate; 231. a magnetic baffle column; 240. placing a block; 300. a hook mechanism; 310. a lifting hook; 320. a limiting piece; 321. a magnetic stop block; 400. a cable mechanism; 500. a rotating mechanism; 510. a connecting column; 520. a mounting plate; 521. a limiting bottom plate; 530. a rotating frame; 531. a driven gear; 532. a torsion bar; 540. a large motor; 541. a drive gear; 610. a fixed block; 620. a rotating lever; 630. the ball sleeve is rotated.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

As shown in fig. 1 to 9, an embodiment of the present invention provides a bridge crane with a protection function, including a bridge crane, a beam trolley 100, a pulley mechanism 200, a hook mechanism 300, a cable mechanism 400, and a rotation mechanism 500. The bridge crane is slidingly disposed on the ground, the bridge crane having a cross beam, and the cross beam trolley 100 is slidingly mounted on the cross beam of the bridge crane. The cable mechanism 400 includes two vertically disposed cables, one end of which is attached to the cross beam trolley 100. The pulley mechanism 200 includes two pulley cases 210 and two pulleys 211, the two pulley cases 210 are parallel to each other, and a connection plate 230 is fixedly provided between the two pulley cases 210. The pulleys 211 are vertically arranged, each pulley 211 is rotatably arranged in one pulley shell 210 around the axis of the pulley 211, the other end of each cable is wound around one pulley 211 and then connected with the beam trolley 100, and when the beam trolley is in an initial state, the projection line of the pulley 211 on the beam trolley 100 is a reference line from bottom to top.

The connecting plate 230 is provided with a mounting hole, the lifting hook mechanism 300 comprises a lifting hook 310, the upper end of the lifting hook 310 is rotatably arranged in the mounting hole, and the lifting hook 310 is in friction transmission fit with the mounting hole. After the lifting hook 310 lifts the weight, the lifting hook 310 is rotated, and the lifting hook 310 drives the pulley mechanism 200 to rotate through the connecting plate 230, so that the pulley 211 forms an included angle between a projection line and a reference line on the beam trolley 100 and makes the cable twist when seen from bottom to top. The rotation mechanism 500 is fixedly provided to the girder trolley 100, and after the weight is lifted by the hook 310, the rotation mechanism 500 resets the cable mechanism 400 and the pulley mechanism 200 by twisting the cable before the weight is removed.

In another embodiment, at least one placement block 240 is fixedly disposed on each pulley shell 210. The pulley 211 has two opposite tapered surfaces, between which a groove for installing a cable is provided, and the cable can be biased toward any one of the tapered surfaces. The bridge crane with a protective function further includes a plurality of sensing mechanisms, each of which includes a fixed block 610, a rotating rod 620, a rotating ball sleeve 630, and an angle sensor. Each of the fixing blocks 610 is fixedly disposed on one of the placement blocks 240, one end of the rotation rod 620 is horizontally rotatably disposed on the fixing block 610, and the other end of the rotation rod 620 is fixedly provided with a collar. The rotating ball sleeve 630 is sleeved on the cable, and the rotating ball sleeve 630 and the lantern ring can rotate relatively. In the initial state, the cable is in the ring groove, and the projection of the rotation lever 620 in the horizontal direction is perpendicular to the axis of the pulley housing 210. An angle sensor is mounted on the placement block 240, and when the cable is biased toward one of the conical surfaces, the cable drives the rotation lever 620 to rotate, and the angle sensor senses a deflection angle between a projection of the rotation lever 620 in a horizontal direction and an axis of the pulley housing 210.

When the cable is twisted, the cable deviates from the middle position of the pulley 211 and approaches one side of the pulley 211, and the cable drives the rotation rod 620 to rotate synchronously, so that the projection of the rotation rod 620 in the horizontal direction is no longer perpendicular to the axis of the pulley housing 210. The angle sensor senses the deflection angle between the projection of the rotation lever 620 in the horizontal direction and the axis of the pulley housing 210, and the value measured by the angle sensor reflects the deflection angle between the projection line of the pulley 211 on the beam trolley 100 and the reference line, as seen from the bottom up.

In another embodiment, the bridge crane with protection function further comprises an adjusting mechanism, wherein the adjusting mechanism comprises a magnetic baffle post 231, a limiting piece 320 and a magnetic stop 321. The magnetic blocking post 231 is fixedly disposed on the connection plate 230. The limiting member 320 is horizontally disposed, and rotatably disposed at an upper end of the hook 310 around its axis, and a channel is formed in a peripheral wall of the limiting member 320. The magnetic stopper 321 is slidably disposed in the passage along the radial direction of the stopper 320. The magnetic stopper 321 has a first state and a second state, when the magnetic stopper 321 is in the first state, the magnetic stopper 321 is outside the stopper 320 and contacts the magnetic stopper 231, and when the magnetic stopper 321 is in the second state, the magnetic stopper 321 is inside the stopper 320, and the magnetic stopper 321 is out of contact with the magnetic stopper 231.

In another embodiment, a small cylinder is disposed in the limiting member 320, and the small cylinder is used to control the magnetic stop 321 to move along the radial direction of the limiting member 320. The magnetic stop 321 and the magnetic stop 231 are all magnetic on the side where they are in contact with each other, and when the magnetic stop 321 is in the first state, the magnetic stop 321 and the magnetic stop 231 are magnetically attracted. The small cylinder controls the magnetic stopper 321 to move toward the inside of the stopper 320 so that the magnetic stopper 321 is out of contact with the magnetic stopper 231.

When the weight is lifted, the magnetic stop 321 is in the first state, and the pulley housing 210 rotates to drive the limiting member 320 to rotate synchronously. When the hook 310 is not rotated any more, the magnetic stopper 321 is moved toward the inside of the stopper 320 by the small cylinder before the weight is removed, so that the magnetic stopper 321 is out of contact with the magnetic stopper 231. The stopper 320 is then rotated, and the magnetic stopper 321 is returned to the original position by the value measured by the angle sensor and is not rotated any more, and then the small cylinder is controlled to eject the magnetic stopper 321 from the passage. The magnetic stopper 321 is returned to the initial position first, and when the magnetic stopper 231 is rotated back to the initial position, the magnetic stopper 321 and the magnetic stopper 231 magnetically attract each other, thereby defining the position of the magnetic stopper 231 and preventing the pulley housing 210 from deviating from the initial position.

In another embodiment, a small motor is disposed in the hook 310, and an output shaft of the small motor is fixedly connected to the limiting member 320. The small motor rotates and drives the stopper 320 to rotate. The small motor can also lock the limiter 320 such that the limiter 320 is no longer rotating.

In another embodiment, the bridge crane with the protection function further comprises a controller for receiving data of the angle sensor and transmitting the data to the small motor to rotate and to enable the small cylinder to stretch and retract.

In another embodiment, the rotation mechanism 500 includes a connection post 510, a mounting plate 520, a turret 530, a large motor 540, a driven gear 531, and a plurality of torsion bars 532. The upper end of the connection column 510 is fixedly connected to the lower end of the beam trolley 100, and the mounting plate 520 is fixedly arranged at the lower end of the connection column 510. The rotating frame 530 is rotatably provided at the lower end of the mounting plate 520, and the driven gear 531 is horizontally provided and rotatably provided on the rotating frame 530 about its own axis.

The torsion bars 532 are uniformly arranged along the circumferential direction of the driven gear 531, each torsion bar 532 extends along the radial direction of the driven gear 531, one end of the torsion bar 532 is fixedly connected to the turret 530, and the other end of the torsion bar 532 is used for abutting against the cable. The large motor 540 is fixedly arranged on the mounting plate 520, and a driving gear 541 for meshing with the driven gear 531 is fixedly arranged on an output shaft of the large motor 540. The lower end of the mounting plate 520 is fixedly arranged on a limiting bottom plate 521, and the limiting bottom plate 521 is positioned at the lower end of the rotating frame 530.

The large motor 540 rotates, the large motor 540 drives the driven gear 531 to rotate through the driving gear 541, and then drives the rotating frame 530 to rotate, the rotating frame 530 drives the torsion bar 532 to rotate, the torsion bar 532 applies a counter torque force to the cable, the counter torque force of the cable is increased, so that the pulley mechanism 200 rotates relative to the hook mechanism 300, and the pulley mechanism 200 returns to the initial position.

In another embodiment, the connection post 510 is capable of telescoping, and a hydraulic rod for controlling the length of the connection post 510 is installed in the connection post 510. The length of the connection post 510 is adjusted according to the overall length of the cable so that the rotation mechanism 500 is at the middle position of the cable, thereby saving more effort when the pulley mechanism 200 is reset by the rotation mechanism 500.

In another embodiment, a hoist for adjusting the length of the cable is installed in the girder trolley 100. According to different use environments, the whole length of the cable is adjusted through the winch.

In another embodiment, the beam trolley 100 is provided with a plurality of travelling wheels 110, the travelling wheels 110 can rotate around the axis of the beam trolley, the travelling wheels 110 are slidably arranged on the beam of the bridge crane, and the beam trolley 100 is also provided with a trolley motor for driving the travelling wheels 110 to rotate. The trolley motor is started and the road wheels 110 are rotated, thereby causing the cross beam trolley 100 to slide on the cross beam of the bridge crane.

The working process comprises the following steps: in the initial state, the cable is naturally vertical and does not twist, and the projection line of the pulley 211 on the beam trolley 100 is taken as a reference line when seen from bottom to top. The magnetic stopper 321 is in a first state in which the magnetic stopper 321 and the magnetic stopper 231 are magnetically attracted, and the cable is wound in the ring groove in the middle of the pulley 211.

The weight is installed on the lifting hook 310, and an operator rotates the weight according to the working environment requirement, so that the lifting hook 310 synchronously rotates, and the lifting hook 310 drives the connecting plate 230 to rotate due to friction transmission fit between the lifting hook 310 and the connecting plate 230, so that the pulley shell 210 rotates, and the mooring rope is twisted at the moment. The rotation angles of the hook 310 and the pulley housing 210 are different due to the torsion of the cable and the friction of the hook 310 applied to the pulley housing 210. Because the magnetic stop 321 and the magnetic stop post 231 attract each other, the pulley shell 210 rotates to drive the limiting member 320 to rotate synchronously, i.e. the limiting member 320 rotates relative to the lifting hook 310.

Before the weight is removed, an operator holds the weight all the time and adjusts the angle of the weight according to the requirements. The operator rotates the hook 310 to adjust the position of the weight without rotating the hook 310, and when the hook 310 is not in the initial position, the cable is twisted, and the pulley 211 creates an angle between the projected line on the beam trolley 100 and the reference line when viewed from the bottom to the top.

The angle sensor transmits the obtained value to the controller, and the controller enables the magnetic stop 321 to move towards the inside of the limiting piece 320 through the small air cylinder, so that the magnetic stop 321 is out of contact with the magnetic stop post 231. Then the controller controls the small motor to rotate, the small motor drives the limiting piece 320 to rotate, so that the magnetic stop block 321 returns to the initial position, and the limiting piece 320 is locked by the small motor and does not rotate any more. The initial position of the magnetic stopper 321 is the position of the magnetic stopper 321 relative to the beam trolley 100 in the initial state, and the small cylinder is controlled to eject the magnetic stopper 321 from the channel.

The large motor 540 rotates, the large motor 540 drives the driven gear 531 to rotate through the driving gear 541, and then drives the rotating frame 530 to rotate, the rotating frame 530 drives the torsion bar 532 to rotate, the torsion bar 532 applies a counter torque force to the cable, the counter torque force of the cable is increased, so that the pulley mechanism 200 rotates relative to the hook mechanism 300, and the pulley mechanism 200 returns to the initial position. Since the magnetic stopper 321 is in an extended state, the magnetic stopper 231 is blocked and attracted and fixed by the magnetic stopper 321, and at this time, the large motor 540 is reversed, so that the large motor 540 returns to the initial position. And then the weight is removed, and the pulley mechanism 200 is returned to the initial position, so that the weight can not be randomly rotated when being removed, and the safety of operators is ensured.

The heavier the weight lifted by the hook 310, the greater the rotational friction between the pulley mechanism 200 and the hook mechanism 300 will result in insufficient counter-torque of the cable mechanism 400, so that when the weight is heavier, the amount of rotation of the turret 530 will be increased to achieve greater counter-torque, and vice versa.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.

Claims

1. Bridge crane with safeguard function, its characterized in that:

the device comprises a bridge crane, a beam trolley, a pulley mechanism, a lifting hook mechanism, a cable mechanism and a rotating mechanism; the bridge crane is arranged on the ground in a sliding manner, and the beam trolley is arranged on the bridge crane in a sliding manner; the cable mechanism comprises a cable, one end of which is connected to the crossbeam trolley;

the pulley mechanism comprises a pulley shell and a pulley, and a connecting plate is fixedly arranged at the lower end of the pulley shell; the pulley is rotatably arranged in the pulley shell around the axis of the pulley, the other end of the cable is wound on one pulley and then connected with the beam trolley, and when in an initial state, the projection line of the pulley on the beam trolley is taken as a reference line from bottom to top; the lifting hook mechanism comprises a lifting hook which is rotatably arranged on the connecting plate and is in friction transmission fit with the connecting plate; the lifting hook is rotated, and the lifting hook drives the pulley mechanism to rotate through the connecting plate, so that an included angle is formed between a projection line and a reference line on the crossbeam trolley when the pulley is seen from bottom to top, and the mooring rope is twisted; the rotating mechanism is fixedly arranged on the beam trolley, and after the lifting hook lifts the heavy object, the rotating mechanism resets the cable mechanism and the pulley mechanism through the torsion cable before the heavy object is dismounted.

2. The bridge crane with protection function according to claim 1, wherein:

at least one placing block is fixedly arranged on the pulley shell; the pulley is provided with two opposite conical surfaces, a ring groove for installing a cable is arranged between the two conical surfaces, and the cable can deviate to any one conical surface;

the bridge crane with the protection function further comprises a plurality of sensing mechanisms, wherein each sensing mechanism comprises a fixed block, a rotating rod, a rotating ball sleeve and an angle sensor; each fixed block is fixedly arranged on one placing block, one end of the rotating rod can be horizontally and rotatably arranged on the fixed block, and the other end of the rotating rod is fixedly provided with a lantern ring; the rotating ball sleeve is arranged on the cable, and the rotating ball sleeve and the lantern ring can rotate relatively; in the initial state, the cable is positioned in the annular groove, and the projection of the rotating rod in the horizontal direction is perpendicular to the axis of the pulley shell; the angle sensor is arranged on the placing block, when the cable deviates to one of the conical surfaces, the cable drives the rotating rod to rotate, and the angle sensor is used for sensing the deflection angle between the projection of the rotating rod in the horizontal direction and the axis of the pulley shell.

3. The bridge crane with protection function according to claim 1, wherein:

the bridge crane with the protection function further comprises an adjusting mechanism, wherein the adjusting mechanism comprises a magnetic baffle column, a limiting piece and a magnetic stop block; the magnetic baffle column is fixedly arranged on the connecting plate; the limiting piece is horizontally arranged and rotationally arranged at the upper end of the lifting hook around the axis of the limiting piece, and a channel is formed in the peripheral wall of the limiting piece; the magnetic stop block can be arranged in the channel in a sliding manner along the radial direction of the limiting piece; the magnetic force dog has first state and second state, and when magnetic force dog was in first state, magnetic force dog was in the locating part outward to with magnetism fender post contact, when magnetic force dog was in the second state, magnetic force dog was in the locating part, magnetic force dog and magnetism fender post break away from the contact.

4. A bridge crane with protection function according to claim 3, characterized in that:

a small air cylinder is arranged in the limiting piece and used for controlling the magnetic force stop block to move along the radial direction of the limiting piece; the magnetic stop block and the magnetic stop post are magnetic on one side which is contacted with each other, and when the magnetic stop block is in a first state, the magnetic stop block and the magnetic stop post are attracted by magnetic force; the small cylinder controls the magnetic stop block to move towards the inside of the limiting piece, so that the magnetic stop block is separated from contact with the magnetic stop post.

5. A bridge crane with protection function according to claim 3, characterized in that:

a small motor is arranged in the lifting hook, and an output shaft of the small motor is fixedly connected with the limiting piece.

6. The bridge crane with protection function according to claim 5, wherein:

the bridge crane with the protection function further comprises a controller, wherein the controller is used for receiving data of the angle sensor and transmitting the data to the small motor to rotate and enable the small cylinder to stretch out and draw back.

7. The bridge crane with protection function according to claim 1, wherein:

the rotating mechanism comprises a connecting column, a mounting plate, a rotating frame, a large motor, a driven gear and a plurality of torsion bars; the upper end of the connecting column is fixedly connected to the lower end of the beam trolley, and the mounting plate is fixedly arranged at the lower end of the connecting column; the rotating frame is rotatably arranged at the lower end of the mounting plate, the driven gear is horizontally arranged and is rotatably arranged on the rotating frame around the axis of the driven gear; the torsion bars are uniformly arranged along the circumferential direction of the driven gear, each torsion bar extends along the radial direction of the driven gear, one end of each torsion bar is fixedly connected to the rotating frame, and the other end of each torsion bar is used for propping against the mooring rope; the large motor is fixedly arranged on the mounting plate, and a driving gear meshed with the driven gear is fixedly arranged on an output shaft of the large motor.

8. The bridge crane with protection function according to claim 7, wherein:

the connecting column can stretch and retract.

9. The bridge crane with protection function according to claim 1, wherein:

a winch for adjusting the length of the mooring rope is arranged in the crossbeam trolley.

10. The bridge crane with protection function according to claim 1, wherein:

the beam trolley is provided with a plurality of travelling wheels which are slidingly arranged on the bridge crane.