Steel box girder rotary positioning device for cantilever crane and working method of steel box girder rotary positioning device

Abstract

The invention relates to the technical field of steel box girder installation, and particularly discloses a steel box girder rotary positioning device for a cantilever crane and a working method of the steel box girder rotary positioning device. A steel box girder rotary positioning device for a cantilever crane comprises a positioning device, a plurality of lifting hooks are installed on the positioning device, and the lifting hooks are connected with lifting rings on a steel box girder body. A lower frame and an upper frame are arranged in the positioning device, the lifting hook is mounted on the lower side of the lower frame, and a driving motor for driving the lower frame to rotate is mounted between the lower frame and the upper frame; two groups of traction units are mounted on the positioning device, the two groups of traction units are respectively positioned at two opposite angles of the positioning device, each traction unit comprises a traction rope, and the traction rope is wound on the winding mechanism. In the posture adjusting process of the steel box girder body, the driving motor serves as a main power source, the traction rope plays an auxiliary role, in this way, the manual operation difficulty in the traction process is greatly reduced, and the process is stable and safer.

Description

Technical Field

[0001] The invention belongs to the technical field of steel box girder installation, and in particular relates to a steel box girder rotation positioning device for a cantilever crane and a working method thereof. Background Art

[0002] Cantilever crane is an industrial component and a light-duty crane. It consists of a column, a slewing arm slewing drive device and an electric hoist. It has the characteristics of light weight, large span, large lifting capacity, economy and durability.

[0003] In a Chinese patent with announcement number CN 112921820 A, a cable-stayed bridge steel box girder cantilever lifting matching system and method are disclosed, which include: a bridge crane, which is arranged at the cantilever end of the assembled steel box girder segment when in use, and is used to lift the steel box girder segment to be assembled to a set height; a posture monitoring device, which is arranged on the assembled steel box girder segment and the steel box girder segment to be assembled when in use, and is used to monitor the coordinates of the set position of the steel box girder segment to be assembled; a posture adjustment device, which is arranged on the bridge crane and is connected to the steel box girder segment to be assembled when in use, and is used to adjust the posture of the steel box girder segment to be assembled so that it can be connected to the assembled steel box girder segment.

[0004] However, the above device has the following problems during use:

[0005] Before the steel box girder is spliced, it is necessary to adjust the posture of the steel box girder. At present, when adjusting the posture, two traction ropes are mostly set at the diagonal positions of the steel box girder. The two traction ropes are controlled by multiple staff members to adjust the posture of the steel box girder to the specified angle. However, the following problems exist in the above adjustment process:

[0006] When the traction rope is manually controlled for adjustment, the traction rope is used as the power source for posture adjustment. If the traction speed is fast during the traction process, it is easy for only one traction rope to provide force, which leads to higher requirements for the strength control of the personnel on one of the traction ropes. Therefore, the process of adjusting the posture of the steel box by traction rope requires the coordination of multiple personnel, and requires high professional quality and team tacit understanding of the personnel, which makes the adjustment of the posture of the steel box girder more difficult and the degree of danger during the operation is higher. Therefore, the present application proposes a steel box girder rotation positioning device for a cantilever crane and a working method thereof. Summary of the invention

[0007] The object of the present invention is to provide a steel box girder rotation positioning device for a cantilever crane and a working method thereof, so as to solve the problems raised by the above-mentioned background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions: a steel box girder rotation positioning device for a cantilever crane, comprising a positioning device, a plurality of hooks are installed on the positioning device, and the hooks are connected to the lifting rings on the steel box girder body;

[0009] The positioning device is provided with a lower frame and an upper frame, the hook is installed on the lower side of the lower frame, and a driving motor for driving the lower frame to rotate is installed between the lower frame and the upper frame;

[0010] Two groups of traction units are installed on the positioning device, and the two groups of traction units are respectively located at two diagonal positions of the positioning device. The traction units include traction ropes, which are wound around a winding mechanism, and the winding mechanism is installed on the outer wall of the storage box.

[0011] The storage box is installed on the adjustment plate, and the adjustment plate is connected with the positioning device through an angle adjustment component.

[0012] Preferably, five hooks are provided, two of which are aligned with the left area of ​​the steel box girder body, one of which is aligned with the middle position of the steel box girder body, and the last two hooks are aligned with the right area of ​​the steel box girder body.

[0013] Preferably, an outer guide plate is installed between the lower frame and the upper frame, the outer guide plate is installed below the upper frame, the outer guide plate is inserted into the outer guide frame and the two can rotate relative to each other around the center line of the output shaft of the drive motor, and the outer guide frame is installed above the lower frame.

[0014] Preferably, an inner guide plate is provided on one side of the outer guide plate close to the center line of the drive motor, the inner guide plate is inserted into the inner guide frame, the inner guide plate is mounted on the lower side of the upper frame, and the inner guide frame is mounted on the upper side of the lower frame.

[0015] Preferably, the traction rope is inserted into the plug-in hole in the plug-in block, and a knot is provided at the end of the traction rope, the size of the knot is larger than the size of the plug-in hole, and the size of the plug-in hole is larger than the size of the traction rope.

[0016] Preferably, the plug-in block is connected to a pop-up unit, and the pop-up unit can insert the plug-in block into the storage box or pop it out of the storage box.

[0017] Preferably, the pop-up unit includes a pressure plate, which is located in the storage box and cooperates with the guide groove in the storage box. A first inclined surface is provided on the side of the pressure plate close to the plug-in block, and the first inclined surface cooperates with the second inclined surface in the plug-in block. A spring is installed between the pressure plate and the inner wall of the storage box, and a locking hole is provided in the plug-in block, which cooperates with the locking plate, and the locking plate is connected to the locking box. A guide wheel is installed on the plug-in block, and the traction rope passes through the gap between the guide wheel and the plug-in block.

[0018] Preferably, a safety protection component is provided in the traction unit, and the safety protection component includes a cutting knife. Two cutting knives are provided, and the two cutting knives face in opposite directions and are staggered in upper and lower directions.

[0019] Preferably, the cutting knife is connected to the cutting bracket via a central axis, the two cutting knives are connected via a telescopic frame, the telescopic frame is connected to the telescopic rod, guide pieces are installed on both upper and lower sides of the cutting knife, and the traction rope passes through the circular hole in the guide piece.

[0020] A working method of a steel box girder rotation positioning device for a cantilever crane comprises the following steps:

[0021] Step 1: Move the steel box girder body into the working area of ​​the cantilever crane body by using the beam transport vehicle;

[0022] Step 2: Start the cantilever crane body, move the positioning device to the steel box girder body, and connect the positioning device to the steel box girder body through a hook;

[0023] Step 3: Start the angle adjustment components in the two traction units, and the two angle adjustment components drive their respective adjustment plates and storage boxes to rotate to two diagonal positions of the steel box girder body;

[0024] Step 4: Start the locking boxes in the two traction units, which drives the locking plates to move up, and the locking plates are disengaged from the locking holes in the plug-in blocks. The elastic force of the spring can push the pressure plate to move, and the movement of the pressure plate can pop out the plug-in blocks from the storage box. The staff takes the two traction ropes on the two plug-in blocks;

[0025] Step 5: Start the cantilever crane body and use it to move the steel box girder body to the designated area;

[0026] Step 6: Start the drive motor in the positioning device, which can drive the steel box girder body to rotate. During this period, 3-4 workers at each traction rope perform auxiliary control through two traction ropes, and finally the steel box girder body rotates to the specified angle;

[0027] Step 7: Start the cantilever crane body again to move the steel box girder body to the designated position, and then the staff will fix the steel box girder body.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. When the posture of the steel box girder body needs to be adjusted, the drive motor is started, which can drive the lower frame and the steel box girder body to rotate, so that the steel box girder body is rotated to the installation angle, and the outer guide plate, outer guide frame, inner guide plate and inner guide frame between the lower frame and the upper frame can provide guidance for the rotation of the lower frame and the steel box girder body, and at the same time provide support for the lower frame and the steel box girder body, so that the output shaft of the drive motor does not bear the gravity of the lower frame and the steel box girder body. The drive motor is the main power source in the process of adjusting the posture of the steel box girder body, and the traction rope plays an auxiliary role. In this way, the difficulty of manual operation during the traction process is greatly reduced, and the process is relatively stable and safer.

[0030] 2. The present invention provides a traction unit on the positioning device, and the pop-up unit and other components inside the traction unit cooperate with each other to insert the plug-in block into the storage box or pop it out of the storage box. During specific use, the locking box can pull the locking plate up when started, so as to pull the locking plate out of the plug-in block. At this time, the locking plate will be quickly pushed out of the storage box under the action of the spring force. When the locking box is closed, that is, the electromagnet is closed, the locking plate loses the upward pulling force, and it can be inserted into the locking hole in the plug-in block under the action of gravity. At this time, the plug-in block can be locked inside the storage box again, so that the traction rope can be quickly placed in the working position, and the time required in the process is shorter than the time required for manual installation of the traction rope.

[0031] 3. The present invention is internally provided with components such as safety protection components. When the telescopic rod inside is started, it can drive the telescopic frame to move left and right. The left and right movement of the telescopic frame can drive the cutting knives to move closer to or away from each other. If the cutting knives move closer to each other, the traction rope between the two cutting knives can be cut, thereby preventing the steel box girder body from pulling people off the bridge through the traction rope. The cutting knives move away from each other, so the traction rope will not be cut, which can prevent the steel box girder body and the positioning device from dragging the staff off the bridge through the traction rope when they fall. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is one of the structural schematic diagrams of a steel box girder rotation and positioning device for a cantilever crane in the present invention.

[0033] Figure 2 This is the second structural schematic diagram of a steel box girder rotation and positioning device for a cantilever crane in the present invention.

[0034] Figure 3 This is one of the structural schematic diagrams of the positioning device, the steel box girder body, and the traction unit in the present invention.

[0035] Figure 4 For the present invention Figure 3 Schematic diagram of the structure at A in the middle.

[0036] Figure 5 This is the second structural schematic diagram of the positioning device, steel box girder body and traction unit in the present invention.

[0037] Figure 6 This is the third structural schematic diagram of the positioning device, steel box girder body and traction unit in the present invention.

[0038] Figure 7 This is the fourth structural schematic diagram of the positioning device, steel box girder body and traction unit in the present invention.

[0039] Figure 8 For the present invention Figure 7 Schematic diagram of the structure at B in the figure.

[0040] Fig. 9 It is a schematic diagram of the structure of the pop-up unit and the safety protection component in the present invention.

[0041] Fig.10 For the present invention Fig. 9 Schematic diagram of the structure at C in the middle.

[0042] In the figure: 1. Positioning device; 101. Hook; 102. Lower frame; 103. Upper frame; 104. Driving motor; 105. Outer guide plate; 106. Outer guide frame; 107. Inner guide plate; 108. Inner guide frame; 2. Steel box girder body;

[0043] 3. Traction unit; 301. Traction rope; 302. Winding mechanism; 303. Connecting block;

[0044] 304, ejection unit; 3041, pressure plate; 3042, spring; 3043, locking plate; 3044, locking box; 305, guide wheel;

[0045] 306. Safety protection component; 3061. Cutting knife; 3062. Center axis; 3063. Cutting bracket; 3064. Telescopic bracket; 3065. Telescopic rod; 3066. Guide; 307. Storage box; 308. Adjustment plate.

[0046] 4. Cantilever crane body. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Reference Figure 1-Figure 10A steel box girder rotation positioning device for a cantilever crane includes a positioning device 1, on which a plurality of hooks 101 are installed, and the hooks 101 are connected to the lifting rings on the steel box girder body 2. The hooks 101 are provided with five hooks, which can be referred to Figure 3 Two of the hooks 101 are aligned with the left area of ​​the steel box girder body 2, one of the hooks 101 is aligned with the middle position of the steel box girder body 2, and the last two hooks 101 are aligned with the right area of ​​the steel box girder body 2.

[0049] Reference Figure 1 , Figure 2 The positioning device 1 is connected to the cantilever crane body 4, and the cantilever crane body 4 can drive the positioning device 1 to move. The positioning device 1 hooks the steel box girder body 2 through the hook 101. When working, the steel box girder body 2 is moved to the position of the cantilever crane body 4 by the beam transport vehicle, and the positioning device 1 connected to the cantilever crane body 4 hooks the lifting ring on the steel box girder body 2 through the hook 101, and then the positioning device 1 and the steel box girder body 2 are moved to the designated operating position through the cantilever crane body 4.

[0050] When the steel box girder body 2 is transported by a beam transporter, its long side needs to be parallel to the moving direction, and when it is installed, its long side needs to be perpendicular to the moving direction. Therefore, the steel box girder body 2 needs to change its direction by the positioning device 1 before installation. Therefore, a lower frame 102 and an upper frame 103 are provided in the positioning device 1, and a hook 101 is installed at the lower side of the lower frame 102, and a driving motor 104 for driving the lower frame 102 to rotate is installed between the lower frame 102 and the upper frame 103;

[0051] The driving motor 104 located between the lower frame 102 and the upper frame 103 cannot directly bear the gravity from the lower frame 102 and the steel box girder body 2, so an outer guide plate 105 is installed between the lower frame 102 and the upper frame 103, and the outer guide plate 105 is installed below the upper frame 103. The outer guide plate 105 is inserted into the outer guide frame 106 and the two can rotate relative to each other around the center line of the output shaft of the driving motor 104, and the outer guide frame 106 is installed above the lower frame 102;

[0052] It should be noted that an inner guide plate 107 is provided on one side of the outer guide plate 105 close to the center line of the drive motor 104 , and the inner guide plate 107 is inserted into the inner guide frame 108 . The inner guide plate 107 is installed on the lower side of the upper frame 103 , and the inner guide frame 108 is installed on the upper side of the lower frame 102 .

[0053] After the cantilever crane body 4 is used to move the steel box girder body 2 to the designated area, its orientation needs to be adjusted. At this time, the drive motor 104 is started, which can drive the lower frame 102 and the steel box girder body 2 to rotate, so that the steel box girder body 2 is rotated to the installation angle, referring to Figure 3The size of the lower frame 102 is smaller than that of the steel box girder body 2. During the rotation of the lower frame 102, the rotation of the steel box girder body 2 will not be hindered. The outer guide plate 105, outer guide frame 106, inner guide plate 107, and inner guide frame 108 between the lower frame 102 and the upper frame 103 can provide guidance for the rotation of the lower frame 102 and the steel box girder body 2, and at the same time provide support for the lower frame 102 and the steel box girder body 2, so that the output shaft of the drive motor 104 does not bear the gravity of the lower frame 102 and the steel box girder body 2, so that the steel box girder body 2 can rotate smoothly.

[0054] In the process of adjusting the angle of the steel box girder body 2, multiple workers are required to manually assist in the control through the traction rope 301. Therefore, two groups of traction units 3 are installed on the positioning device 1. The two groups of traction units 3 are respectively located at the two diagonal positions of the positioning device 1. The traction unit 3 includes a traction rope 301. The traction rope 301 is wound around a winding mechanism 302. The winding mechanism 302 has a power function. When the winding mechanism 302 is started, it can wind the traction rope 301 or release the traction rope 301. The traction rope 301 is inserted into the plug hole in the plug block 303, and a knot is set at the end of the traction rope 301. The size of the knot is larger than the size of the plug hole. The size of the plug hole is larger than the size of the traction rope 301, and the winding mechanism 302 is installed on the outer wall of the storage box 307.

[0055] In a further embodiment, the plug-in block 303 is connected to an ejection unit 304, and the ejection unit 304 can insert the plug-in block 303 into the storage box 307 or eject it from the storage box 307;

[0056] Specifically, the pop-up unit 304 includes a pressing plate 3041, which is located in the storage box 307 and cooperates with the guide groove in the storage box 307. A first inclined surface is provided on the side of the pressing plate 3041 close to the plug-in block 303, and the first inclined surface cooperates with the second inclined surface in the plug-in block 303. A spring 3042 is installed between the pressing plate 3041 and the inner wall of the storage box 307, and a locking hole is provided in the plug-in block 303, and the locking hole cooperates with the locking plate 3043, and the locking plate 3043 is connected to the locking box 3044.

[0057] When started, the locking box 3044 can pull the locking plate 3043 upward (the corresponding electromagnet assembly is installed inside the locking box 3044), thereby pulling the locking plate 3043 out of the plug-in block 303. At this time, the locking plate 3043 will be quickly pushed out of the storage box 307 under the action of the elastic force of the spring 3042, and the rope head of the traction rope 301 is located on the plug-in block 303. At this time, the staff can get the rope head of the traction rope 301 and perform auxiliary control through the traction rope 301 during the rotation of the steel box girder body 2. When the locking box 3044 is closed, that is, the electromagnet is closed, the locking plate 3043 loses the upward pulling force, and it can be inserted into the locking hole in the plug-in block 303 under the action of gravity. At this time, the plug-in block 303 can be locked in the storage box 307 again.

[0058] It should be noted that a guide wheel 305 is installed on the plug-in block 303 , and the traction rope 301 passes through the gap between the guide wheel 305 and the plug-in block 303 .

[0059] In a further embodiment, when the worker assists the steel box girder body 2 in rotating by the traction rope 301, if an accident occurs and the accident cannot be solved by manpower, in order to avoid personal injury, the worker needs to quickly loosen the traction rope 301. However, in actual operation, the reaction speed of the workers varies. In order to prevent the steel box girder body 2 from falling due to an accident and pulling the worker down, a safety protection component 306 is provided in the traction unit 3. When the safety protection component 306 is started, the traction rope 301 in the traction unit 3 can be cut off.

[0060] Specifically, the safety protection component 306 includes a cutting knife 3061, and two cutting knives 3061 are provided. The two cutting knives 3061 face oppositely and are staggered up and down. The cutting knives 3061 are connected to the cutting bracket 3063 through the central axis 3062. The two cutting knives 3061 are connected through a telescopic frame 3064. The telescopic frame 3064 is connected to a telescopic rod 3065. When the telescopic rod 3065 is started, it can drive the telescopic frame 3064 to move left and right. The left and right movement of the telescopic frame 3064 can drive the cutting knives 3061 to move closer to or away from each other. If the cutting knives 3061 are close to each other, the traction rope 301 between the two cutting knives 3061 can be cut off, thereby preventing the steel box girder body 2 from pulling people off the bridge through the traction rope 301. The cutting knives 3061 are far away from each other, so that the traction rope 301 will not be cut.

[0061] It should be noted that guide members 3066 are installed on the upper and lower sides of the cutting knife 3061. The traction rope 301 passes through the circular hole in the guide member 3066. The movement of the traction rope 301 is restricted by the circular hole to prevent the traction rope 301 from contacting the cutting knife 3061 during movement and to prevent the traction rope 301 from being damaged by the cutting knife 3061.

[0062] The storage box 307 is installed on the adjustment plate 308, and the adjustment plate 308 is connected to the positioning device 1 through an angle adjustment component. The angle adjustment component can drive the adjustment plate 308 and other components to rotate forward and reverse, allowing it to rotate to the diagonal position of the steel box girder body 2, and the initial point of the traction rope 301 is also located there. It can also drive the adjustment plate 308 to rotate to the position of the lower frame 102, that is, it is located above the steel box girder body 2, and will not hinder the loading and unloading of the steel box girder body 2.

[0063] A working method of a steel box girder rotation positioning device for a cantilever crane comprises the following steps:

[0064] Step 1: Move the steel box girder body 2 into the working area of ​​the cantilever crane body 4 by using a beam transport vehicle;

[0065] Step 2: Start the cantilever crane body 4, move the positioning device 1 to the steel box girder body 2, and connect the positioning device 1 to the steel box girder body 2 through the hook 101;

[0066] Step 3: Start the angle adjustment components in the two traction units 3, and the two angle adjustment components drive their respective adjustment plates 308 and storage boxes 307 to rotate to two diagonal positions of the steel box girder body 2;

[0067] Step 4: Start the locking boxes 3044 in the two traction units 3, which drives the locking plate 3043 to move upward, and the locking plate 3043 is disengaged from the locking hole in the plug-in block 303. The elastic force of the spring 3042 can push the pressure plate 3041 to move, and the movement of the pressure plate 3041 can pop out the plug-in block 303 from the storage box 307. The staff takes the two traction ropes 301 on the two plug-in blocks 303;

[0068] Step 5: Start the cantilever crane body 4 and use it to move the steel box girder body 2 to the designated area;

[0069] Step 6: Start the driving motor 104 in the positioning device 1, which can drive the steel box girder body 2 to rotate. During this period, 3-4 workers at each traction rope 301 perform auxiliary control through two traction ropes 301, and finally the steel box girder body 2 rotates to a specified angle;

[0070] Step 7: Start the cantilever crane body 4 again to move the steel box girder body 2 to the designated position, and then the staff fixes the steel box girder body 2. In this way, the single rotation and positioning of the steel box girder body 2 is completed. After the steel box girder body 2 is fixed, it is necessary to separate the lifting ring at the steel box girder body 2 from the hook 101 on the positioning device 1, move the positioning device 1 and the various components in the traction unit 3 to the original position, and then feed, rotate and align the steel box girder body 2 again.

[0071] Working principle:

[0072] The angle adjustment components in the two traction units 3 are started, which drive the adjustment plate 308 and the storage box 307 to rotate to the two diagonal positions of the steel box girder body 2; then, the locking boxes 3044 in the two traction units 3 are started, which drive the locking plate 3043 to move up, and the locking plate 3043 is disengaged from the locking hole in the plug-in block 303. The elastic force of the spring 3042 can push the pressure plate 3041 to move, and the movement of the pressure plate 3041 can pop out the plug-in block 303 from the storage box 307, and the staff takes the two traction ropes 301 on the two plug-in blocks 303; then, the cantilever crane body 4 is started, and the steel box girder body 2 is moved to the designated area through it;

[0073] Finally, the driving motor 104 in the positioning device 1 is started, which can drive the steel box girder body 2 to rotate. During this period, 3-4 workers at each traction rope 301 perform auxiliary control through two traction ropes 301. Finally, the steel box girder body 2 rotates to the specified angle, thus completing the rotation of the steel box girder body 2.

[0074] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A steel box girder rotation positioning device for a cantilever crane, comprising a positioning device (1), characterized in that: A plurality of hooks (101) are installed on the positioning device (1), and the hooks (101) are connected to the lifting rings on the steel box girder body (2); The positioning device (1) is provided with a lower frame (102) and an upper frame (103), the hook (101) is installed on the lower side of the lower frame (102), and a driving motor (104) for driving the lower frame (102) to rotate is installed between the lower frame (102) and the upper frame (103); Two groups of traction units (3) are installed on the positioning device (1), and the two groups of traction units (3) are respectively located at two diagonal positions of the positioning device (1), and the traction units (3) include traction ropes (301), and the traction ropes (301) are wound around a winding mechanism (302), and the winding mechanism (302) is installed on the outer wall of the storage box (307); The storage box (307) is mounted on an adjustment plate (308), and the adjustment plate (308) is connected to the positioning device (1) via an angle adjustment assembly.

2. The steel box girder rotation positioning device for a cantilever crane according to claim 1, characterized in that: There are five hooks (101), two of which are aligned with the left area of ​​the steel box girder body (2), one of which is aligned with the middle position of the steel box girder body (2), and the last two hooks (101) are aligned with the right area of ​​the steel box girder body (2).

3. The steel box girder rotation positioning device for a cantilever crane according to claim 1, characterized in that: An outer guide plate (105) is installed between the lower frame (102) and the upper frame (103). The outer guide plate (105) is installed below the upper frame (103). The outer guide plate (105) is inserted into an outer guide frame (106) and the two can rotate relative to each other around the center line of the output shaft of the driving motor (104). The outer guide frame (106) is installed above the lower frame (102).

4. The steel box girder rotation positioning device for a cantilever crane according to claim 3, characterized in that: An inner guide plate (107) is provided on one side of the outer guide plate (105) close to the center line of the drive motor (104); the inner guide plate (107) is inserted into an inner guide frame (108); the inner guide plate (107) is mounted on the lower side of the upper frame (103), and the inner guide frame (108) is mounted on the upper side of the lower frame (102).

5. The steel box girder rotation positioning device for a cantilever crane according to claim 1, characterized in that: The traction rope (301) is inserted into the plug hole in the plug block (303), and a knot is provided at the end of the traction rope (301), the size of the knot is larger than the size of the plug hole, and the size of the plug hole is larger than the size of the traction rope (301).

6. The steel box girder rotation positioning device for a cantilever crane according to claim 5, characterized in that: The plug-in block (303) is connected to an ejection unit (304), and the ejection unit (304) can insert the plug-in block (303) into a storage box (307) or eject it from the storage box (307).

7. The steel box girder rotation positioning device for a cantilever crane according to claim 6, characterized in that: The pop-up unit (304) comprises a pressing plate (3041), the pressing plate (3041) is located in the storage box (307), and the pressing plate (3041) cooperates with the guide groove in the storage box (307), a first inclined surface is provided on the side of the pressing plate (3041) close to the plug-in block (303), the first inclined surface cooperates with the second inclined surface in the plug-in block (303), a spring (3042) is installed between the pressing plate (3041) and the inner wall of the storage box (307), and a locking hole is provided in the plug-in block (303), the locking hole cooperates with the locking plate (3043), the locking plate (3043) is connected to the locking box (3044), a guide wheel (305) is installed on the plug-in block (303), and the traction rope (301) passes through the gap between the guide wheel (305) and the plug-in block (303).

8. The steel box girder rotation positioning device for a cantilever crane according to claim 1, characterized in that: A safety protection component (306) is arranged in the traction unit (3), and the safety protection component (306) comprises a cutting knife (3061). Two cutting knives (3061) are arranged, and the two cutting knives (3061) face in opposite directions and are staggered in upper and lower directions.

9. The steel box girder rotation positioning device for a cantilever crane according to claim 8, characterized in that: The cutting knife (3061) is connected to the cutting bracket (3063) via a central axis (3062), the two cutting knives (3061) are connected via a telescopic frame (3064), the telescopic frame (3064) is connected to a telescopic rod (3065), and guide pieces (3066) are installed on both upper and lower sides of the cutting knife (3061), and the traction rope (301) passes through a circular hole in the guide piece (3066).

10. A working method of a steel box girder rotation positioning device for a cantilever crane, characterized in that , a steel box girder rotation positioning device for a cantilever crane as mentioned in any one of claims 1 to 9 is adopted, and the working method thereof when used comprises the following steps: Step 1: Move the steel box girder body (2) into the working area of ​​the cantilever crane body (4) by using a beam transport vehicle; Step 2: Start the cantilever crane body (4), move the positioning device (1) to the steel box girder body (2), and connect the positioning device (1) to the steel box girder body (2) through the hook (101); Step 3: Start the angle adjustment components in the two traction units (3), and the two angle adjustment components drive their respective adjustment plates (308) and storage boxes (307) to rotate to two diagonal positions of the steel box beam body (2); Step 4: Start the locking boxes (3044) in the two traction units (3), which drives the locking plate (3043) to move upward, and the locking plate (3043) is disengaged from the locking hole in the plug-in block (303). The elastic force of the spring (3042) can push the pressure plate (3041) to move, and the movement of the pressure plate (3041) can pop out the plug-in block (303) from the storage box (307). The staff takes the two traction ropes (301) on the two plug-in blocks (303); Step 5: Start the cantilever crane body (4) and use it to move the steel box girder body (2) to the designated area; Step 6: Start the driving motor (104) in the positioning device (1), which can drive the steel box girder body (2) to rotate. During this period, 3-4 workers at each traction rope (301) perform auxiliary control through two traction ropes (301), and finally the steel box girder body (2) rotates to a specified angle; Step 7: Start the cantilever crane body (4) again to move the steel box girder body (2) to the designated position, and then the staff fixes the steel box girder body (2).

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