CN114803822A

CN114803822A - Lifting appliance for variable cross-section steel-concrete composite beam

Info

Publication number: CN114803822A
Application number: CN202210575069.1A
Authority: CN
Inventors: 杨文峰; 苏效友; 劳海燕; 应甲佳; 唐林书; 黎明; 葛林杰
Original assignee: Ningbo Communication Engineering Construction Group Co Ltd
Current assignee: Ningbo Communication Engineering Construction Group Co Ltd
Priority date: 2022-05-24
Filing date: 2022-05-24
Publication date: 2022-07-29

Abstract

The invention provides a lifting appliance for a variable cross-section steel-concrete composite beam. The lifting appliance for the variable cross-section steel-concrete composite beam comprises a box beam; a fixing mechanism; the supporting mechanism comprises a steel cable, a fixed pulley, a roller and a fixed seat, the fixed seat is fixed inside the fixed mechanism, one end of the fixed seat is rotatably connected with the roller, and the side wall of the roller is wound with the steel cable; the driving mechanism comprises a first variable frequency motor, a first gear and a second gear, the first variable frequency motor is symmetrically installed inside the fixing mechanism and is connected with the first gear, the first gear is meshed with the second gear, and the second gear is fixed on the side wall of the roller; a limiting mechanism; a compression mechanism; and the reinforcing mechanism is connected with the fixed seat and clamped with the second gear. The lifting appliance for the variable cross-section steel-concrete composite beam has the advantage of facilitating horizontal lifting of the box beam.

Description

Lifting appliance for variable cross-section steel-concrete composite beam

Technical Field

The invention relates to the technical field of steel-concrete composite beam construction, in particular to a lifting appliance for a variable cross-section steel-concrete composite beam.

Background

The steel-concrete composite beam is a novel reasonable bridge type with large spanning capacity and small building height as a bridge structure form, has the characteristics of a concrete bridge and a steel bridge, and is widely applied to urban bridges. The common main beam is of a steel structure and bears the load of the bridge deck together with the cast-in-place reinforced concrete bridge deck, so that the dead weight of the bridge can be reduced. The structure enables the reinforced concrete slab and the box girder to be jointly bent under the vertical load action through the shear key, the required bearing area of the upper flange of the box girder is greatly reduced, and the stress characteristic of concrete and steel is fully exerted. Meanwhile, the reinforced concrete slab and the box girder are combined into a whole, the rigidity of the section of the reinforced concrete slab is increased, and therefore the using amount of steel can be reduced. In addition, due to the construction characteristics of the steel structure, the upper and lower structures of the bridge can be constructed simultaneously, the construction progress is accelerated, and a plurality of mature design and construction experiences are obtained along with the development of the steel-concrete composite beam bridge.

When the box girder needs to be lifted, the sling needs to be connected with the box girder, when the box girder is lifted by the lifting appliance and the sling, due to factors such as the length of the steel rope and the structure of the box girder, when the box girder is initially lifted, one end of the lifted box girder is inclined due to unstable gravity center, the lifted box girder tends to be horizontal in aspects of adjusting the length of the steel rope, the connection position of the sling and the box girder and the like by workers, but the adjustment process is troublesome and labor-consuming, and the lifting efficiency of people is reduced.

Therefore, there is a need to provide a new lifting device for a variable cross-section steel-concrete composite beam to solve the above-mentioned technical problems.

Disclosure of Invention

The invention aims to provide a lifting appliance for a variable cross-section steel-concrete composite beam, which is convenient for horizontally lifting a box beam.

In order to solve the technical problem, the invention provides a lifting appliance for a variable cross-section steel-concrete composite beam, which comprises: a box girder; a fixing mechanism; the supporting mechanism is arranged inside the fixing mechanism and comprises a steel cable, a fixed pulley, a roller and a fixed seat, the fixed seat is fixed inside the fixing mechanism, one end of the fixed seat is rotatably connected with the roller, and the side wall of the roller is wound with the steel cable; the fixed pulleys are symmetrically arranged in the fixed mechanism, the steel cable is connected in the fixed pulleys in a sliding manner, and the steel cable is connected with the box girder; the driving mechanism is fixed inside the fixing mechanism and comprises a first variable frequency motor, a first gear and a second gear, the first variable frequency motor is symmetrically installed inside the fixing mechanism and is connected with the first gear, the first gear is meshed with the second gear, and the second gear is fixed on the side wall of the roller; the limiting mechanism is arranged inside the fixing mechanism and is clamped with the roller; the compression mechanism is arranged inside the fixing mechanism and is rotationally connected with the limiting mechanism; and the reinforcing mechanism is connected with the fixed seat and clamped with the second gear.

Preferably, the fixed establishment includes fixed case, rings and a supporting beam, the internally mounted of fixed case the fixing base, just the top installation of fixed case rings, just the inside department fixed connection placed in the middle of fixed case the supporting beam.

Preferably, the reinforcing mechanism comprises a convex block, a fixed shaft, a sliding rod, a second spring, a fixed disc and a squeezing plate, one end of the roller is fixedly connected with the fixed shaft, the fixed disc is fixed on the side wall of the supporting beam, and the fixed disc is rotatably connected with the fixed shaft; the fixed disc is internally connected with a plurality of sliding rods in a sliding manner, and one end of each sliding rod is fixedly connected with the extrusion plate; the side wall of the sliding rod is sleeved with the second spring, and the second spring is fixed in the fixed disc; the second gear, the fixed shaft, the slide rod and the side wall of the extrusion plate are respectively provided with the lug, the lug on the side wall of the slide rod is clamped with the lug on the side wall of the second gear, and the lug on the side wall of the fixed shaft is clamped with the lug on the side wall of the extrusion plate.

Preferably, the second gear and the protruding block on the side wall of the fixed shaft are distributed annularly, and the side wall of the protruding block is of an arc-shaped structure.

Preferably, the compression mechanism comprises a second variable frequency motor, a mounting shaft, a compression rod and a compression block, the second variable frequency motor is symmetrically mounted inside the support beam, and the second variable frequency motor is connected with the mounting shaft; the compression rods are arranged on the side wall of the extrusion plate at equal intervals; the side wall of the installation shaft is provided with a plurality of compression blocks, and the compression blocks and the compression rods are in sliding connection with the side wall of the compression rods.

Preferably, the side walls of the two ends of the compression block are arc-shaped structures, and the height of the compression block is equal to the longest vertical distance between the sliding rod and the second gear.

Preferably, the limiting mechanism comprises a toothed plate, a limiting plate, a rotating rod, a clamping plate, a first spring and an electromagnet, the toothed plate is mounted on the side wall of the roller respectively in an annular shape, the clamping plate is symmetrically mounted inside the fixed box, the first spring is mounted between the clamping plate and the rotating rod, and the rotating rod is rotatably connected with the side wall of the fixed box; the bottom end of the rotating rod is fixedly connected with the limiting plate, and the limiting plate is clamped with the toothed plate; the side wall of the fixed seat is provided with the electromagnet, and the electromagnet adsorbs the magnetic rotating rod.

Preferably, the toothed plate and the second gear are respectively located at two sides of the drum, and the diameter of the second gear is greater than that of the first gear.

Compared with the prior art, the lifting appliance for the variable cross-section steel-concrete composite beam has the following beneficial effects:

the invention provides a lifting appliance for a variable cross-section steel-concrete composite beam, when the box beam needs to be lifted, a fixing mechanism is firstly connected with a crane, a steel cable is connected with the box beam, the fixing mechanism, a sling and the box beam are lifted upwards by the crane, when the lifted box beam is inclined at one end with unstable gravity center, the box beam is firstly put down, adjusting the length of the steel cable according to the inclination angle and the direction of the box girder, opening the first variable frequency motor corresponding to the steel cable to be adjusted, the first variable frequency motor drives the first gear to rotate, the first gear pushes the second gear and the roller to rotate, the steel cable is unwound from the side wall of the roller or wound on the side wall of the roller, and therefore the length of the steel cable is changed, and the box girder tends to be horizontal when being hoisted; the limiting mechanism is arranged on one side of the roller, the reinforcing mechanism is arranged on the other side of the roller, and the limiting mechanism and the reinforcing mechanism are used for fixing the roller in multiple ways, so that the roller is prevented from rotating in the box girder hoisting process, and the use safety is improved;

the invention provides a lifting appliance for a variable cross-section steel-concrete composite beam, which is characterized in that when a box beam needs to be lifted, a fixing mechanism is connected with a crane, a steel cable is connected with the box beam, the crane lifts the fixing mechanism, a sling and the box beam upwards, when the lifted box beam is inclined due to unstable gravity center, the length of the steel cable is adjusted according to the inclination angle and direction of the box beam, a first variable frequency motor corresponding to the steel cable needs to be adjusted is opened, the first variable frequency motor drives a first gear to rotate, the first gear pushes a second gear and a roller to rotate, the steel cable is loosened from the side wall of the roller or wound on the side wall of the roller, and therefore the length of the steel cable is changed; when the position of the box beam is adjusted, the steel cable moves 5 cm on the side wall of the fixed pulley every time, at the moment, the first variable frequency motor stops running, the roller stops rotating, and meanwhile, the limiting mechanism operates to fix the roller, so that the roller drives the steel cable to move intermittently, the moving speed of the steel cable is reduced, the steel cable is prevented from being untied suddenly on the side wall of the roller, and the box beam is adjusted slowly. After the box girder is adjusted, the limiting mechanisms and the reinforcing mechanisms on the two sides of the roller fix the roller in multiple ways, so that the roller is prevented from rotating in the lifting process of the box girder, and the use safety is improved.

Drawings

Fig. 1 is a schematic structural view of a preferred embodiment of a lifting appliance for a variable cross-section steel-concrete composite beam provided by the invention;

FIG. 2 is a top view of the internal structure of the stationary box shown in FIG. 1;

FIG. 3 is a schematic view of the internal structure of the stationary box shown in FIG. 1;

FIG. 4 is an enlarged view of the structure at A shown in FIG. 2;

FIG. 5 is a schematic view of the rotating rod shown in FIG. 2;

FIG. 6 is a side view of the limiting plate structure shown in FIG. 1;

FIG. 7 is a top view of the mounting shaft configuration shown in FIG. 4;

fig. 8 is a top view of the compression block structure shown in fig. 7.

Reference numbers in the figures: 1. the device comprises a box girder, 2, a supporting mechanism, 21, a steel cable, 22, a fixed pulley, 23, a roller, 24, a fixed seat, 3, a fixed mechanism, 31, a fixed box, 32, a hanging ring, 33, a supporting beam, 4, a driving mechanism, 41, a first variable frequency motor, 42, a first gear, 43, a second gear, 5, a limiting mechanism, 51, a toothed plate, 52, a limiting plate, 53, a rotating rod, 54, a limiting plate, 55, a first spring, 56, an electromagnet, 6, a reinforcing mechanism, 61, a bump, 62, a fixed shaft, 63, a sliding rod, 64, a second spring, 65, a fixed disk, 66, a squeezing plate, 7, a compression mechanism, 71, a second variable frequency motor, 72, a mounting shaft, 73, a compression rod, 74 and a compression block.

Detailed Description

The invention is further described below with reference to the drawings and the embodiments.

Please refer to fig. 1, fig. 2, fig. 3, fig. 4, fig. 5, fig. 6, fig. 7 and fig. 8 in combination, wherein fig. 1 is a schematic structural diagram of a preferred embodiment of a lifting device for a variable cross-section steel-concrete composite beam according to the present invention; FIG. 2 is a top view of the internal structure of the stationary box shown in FIG. 1; FIG. 3 is a schematic view of the internal structure of the stationary box shown in FIG. 1; FIG. 4 is an enlarged view of the structure at A shown in FIG. 2; FIG. 5 is a schematic view of the rotating rod shown in FIG. 2; FIG. 6 is a side view of the limiting plate structure shown in FIG. 1; FIG. 7 is a top view of the mounting shaft configuration shown in FIG. 4; fig. 8 is a top view of the compression block structure shown in fig. 7. The hoist for the variable cross section steel-concrete composite beam includes: a box girder 1; a fixing mechanism 3; the supporting mechanism 2 is installed inside the fixing mechanism 3, the supporting mechanism 2 comprises a steel cable 21, a fixed pulley 22, a roller 23 and a fixed seat 24, the fixed seat 24 is fixed inside the fixing mechanism 3, one end of the fixed seat 24 is rotatably connected with the roller 23, and the side wall of the roller 23 is wound on the steel cable 21; the fixed pulleys 22 are symmetrically arranged inside the fixed mechanism 3, the steel cable 21 is connected inside the fixed pulleys 22 in a sliding manner, and the steel cable 21 is connected with the box girder 1; the driving mechanism 4 is fixed inside the fixing mechanism 3, the driving mechanism 4 comprises a first variable frequency motor 41, a first gear 42 and a second gear 43, the first variable frequency motor 41 is symmetrically installed inside the fixing mechanism 3, the first variable frequency motor 41 is connected with the first gear 42, the first gear 42 is meshed with the second gear 43, and the second gear 43 is fixed on the side wall of the roller 23; the limiting mechanism 5 is mounted inside the fixing mechanism 3, and the limiting mechanism 5 is clamped with the roller 23; the compression mechanism 7 is installed inside the fixing mechanism 3, and the compression mechanism 7 is rotatably connected with the limiting mechanism 5; and the reinforcing mechanism 6 is connected with the fixed seat 24, and the reinforcing mechanism 6 is clamped with the second gear 43.

Fixing mechanism 3 includes fixed case 31, rings 32 and a supporting beam 33, the internally mounted of fixed case 31 fixing base 24, just the top installation of fixed case 31 rings 32, just the inside of fixed case 31 is located fixed connection in the middle of it the supporting beam 33, for convenient use rings 32 prepares the loop wheel machine and links to each other, supporting beam 33 has increased the fastness and the stability of fixed case 31.

The reinforcing mechanism 6 comprises a convex block 61, a fixed shaft 62, a sliding rod 63, a second spring 64, a fixed disc 65 and a pressing plate 66, one end of the roller 23 is fixedly connected with the fixed shaft 62, the fixed disc 65 is fixed on the side wall of the supporting beam 33, and the fixed disc 65 is rotatably connected with the fixed shaft 62; a plurality of sliding rods 63 are slidably connected inside the fixed disc 65, and one end of each sliding rod 63 is fixedly connected with the extrusion plate 66; the side wall of the sliding rod 63 is sleeved with the second spring 64, and the second spring 64 is fixed inside the fixed disc 65; the second gear 43, the fixed shaft 62, the sliding rod 63 and the side wall of the pressing plate 66 are respectively provided with the projection 61, the projection 61 on the side wall of the sliding rod 63 is engaged with the projection 61 on the side wall of the second gear 43, and the projection 61 on the side wall of the fixed shaft 62 is engaged with the projection 61 on the side wall of the pressing plate 66, the second gear 43 and the projection 61 on the side wall of the fixed shaft 62 are distributed annularly, and the side wall of the projection 61 is of an arc-shaped structure, so that in order to facilitate the movement of the pressing plate 66, the pressing plate 66 pushes the sliding rod 63 to move inside the fixed disc 65 to compress the second spring 64, so that the sliding rod 63 moves close to the second gear 43, and meanwhile, the pressing plate 66 is close to the fixed shaft 62, so that the projection 61 on the side wall of the sliding rod 63 is engaged with the projection 61 on the side wall of the second gear 43, the protrusion 61 of the sidewall of the fixed shaft 62 is engaged with the protrusion 61 of the sidewall of the pressing plate 66, so that the second gear 43 and the fixed shaft 62 are fixed, and the drum 23 is fixed.

The compression mechanism 7 comprises a second variable frequency motor 71, a mounting shaft 72, a compression rod 73 and a compression block 74, the second variable frequency motor 71 is symmetrically mounted inside the support beam 33, and the second variable frequency motor 71 is connected with the mounting shaft 72; the compression bars 73 are installed at the side walls of the pressing plate 66 at equal intervals; the side wall of the installation shaft 72 is provided with a plurality of compression blocks 74, and the compression blocks 74 and the compression rods 73 are slidably connected with the side wall of the compression rods 73, the side walls at both ends of the compression blocks 74 are in an arc structure, in order that the second inverter motor 71 moves to push the installation shaft 72 to rotate when the compression plate 66 is pressed, the installation shaft 72 pushes the compression blocks 74 to rotate, the compression blocks 74 press the compression rods 73 at the side wall of the compression plate 66 as required, so that the compression blocks 74 push the compression rods 73 and the compression plate 66 to rotate, and the height of the compression blocks 74 is equal to the longest vertical distance between the sliding rods 63 and the second gears 43, when the compression blocks 74 push the compression rods 73 to the maximum movement distance, the bumps 61 of the side walls 63 of the sliding rods are engaged with the bumps 61 of the side walls of the second gears 43, the protrusion 61 on the sidewall of the fixed shaft 62 is engaged with the protrusion 61 on the sidewall of the pressing plate 66.

The limiting mechanism 5 comprises a toothed plate 51, a limiting plate 52, a rotating rod 53, a clamping plate 54, a first spring 55 and an electromagnet 56, the toothed plate 51 is annularly mounted on the side wall of the drum 23, the clamping plate 54 is symmetrically mounted inside the fixed box 31, the first spring 55 is mounted between the clamping plate 54 and the rotating rod 53, and the rotating rod 53 is rotatably connected with the side wall of the fixed box 31; the bottom end of the rotating rod 53 is fixedly connected with the limit plate 52, and the limit plate 52 is clamped with the toothed plate 51; the installation of fixing base 24's lateral wall electro-magnet 56, just electro-magnet 56 adsorbs to have magnetism bull stick 53, in order to make the operation of electro-magnet 56 produces magnetic force, electro-magnet 56 adsorbs downwards bull stick 53, bull stick 53 rotates downwards and lengthens first spring 55, simultaneously bull stick 53 drives limiting plate 52 downstream block pinion rack 51 will the cylinder 23 is fixed once more.

The toothed plate 51 and the second gear 43 are respectively located at two sides of the drum 23, and the diameter of the second gear 43 is larger than that of the first gear 42, so that the first gear 42 can push the second gear 43 and the drum 23 to rotate more conveniently.

The working principle of the lifting appliance for the variable cross-section steel-concrete composite beam provided by the invention is as follows: when the box girder 1 needs to be lifted, the lifting ring 32 is connected with a crane, the steel cable 21 is connected with the box girder 1, the crane lifts the fixing mechanism 3, the lifting rope 21 and the box girder 1 upwards, when the end of the lifted box girder 1 with unstable gravity center inclines, the length of the steel cable 21 is adjusted according to the inclination angle and direction of the box girder 1, the second variable frequency motor 71 is opened, the second variable frequency motor 71 moves to push the mounting shaft 72 to rotate, the mounting shaft 72 pushes the compression block 74 to rotate, the compression block 74 rotates to separate from the extrusion plate 66 corresponding to the steel cable 21 (as shown in figure 8), at this time, the second spring 64 extends to push the sliding rod 63 and the extrusion plate 66 to move into the supporting beam 33, and the toothed plates 51 are separated from each other, the second gear 42 and the fixed shaft 62 are free from constraint, the electromagnet 56 corresponding to the steel cable 21 to be adjusted is closed, the electromagnet 56 sucks out magnetic force, the first spring 55 extends to push the rotating rod 53 to rotate upwards, and meanwhile, the rotating rod 53 drives the limit plate 52 to be separated from the toothed plate 51, so that the roller 23 is free from constraint; opening the first inverter motor 41 corresponding to the drum 23, wherein the first inverter motor 41 drives the first gear 42 to rotate, and the first gear 42 pushes the second gear 43 and the drum 23 to rotate, so that the steel cable 21 is unwound from the side wall of the drum 23 or the steel cable 21 is wound on the side wall of the drum 23, thereby changing the length of the steel cable 21, and enabling the box girder 1 to be horizontal in the air; when the adjustment when the position of case roof beam 1, at every turn the cable wire 21 is in the lateral wall motion 5 centimetres of fixed pulley 22, this moment first inverter motor 41 stall, cylinder 23 stall, simultaneously the electro-magnet 56 adsorbs to have the magnetism bull stick 53, for the messenger the electro-magnet 56 function produces magnetic force, the electro-magnet 56 adsorbs downwards bull stick 53, bull stick 53 rotates downwards and lengthens first spring 55, simultaneously the bull stick 53 drives limiting plate 52 downstream block toothed plate 51, will the cylinder 23 is fixed, thereby the cylinder 23 intermittent type drives the cable wire 21 motion slows down cable wire 21 velocity of motion, avoids the cable wire 21 is in suddenly the lateral wall of cylinder 23 unties slowly in the sky adjust case roof beam 1. When the adjustment of the box girder 1 is completed, the electromagnet 56 is powered on to maintain the magnetic force, and at the same time, the second inverter motor 71 moves to push the mounting shaft 72 to rotate, the mounting shaft 72 pushes the compression block 74 to rotate, the compression block 74 compresses the compression rod 73 on the side wall of the compression plate 66 as required, so that the compression block 74 pushes the compression rod 73 and the compression plate 66 to rotate, the height of the compression block 74 is equal to the longest vertical distance between the sliding rod 63 and the second gear 43, when the compression block 74 pushes the compression rod 73 to the maximum movement distance, the protrusion 61 on the side wall of the sliding rod 63 is engaged with the protrusion 61 on the side wall of the second gear 43, the protrusion 61 on the side wall of the fixed shaft 62 is engaged with the protrusion 61 on the side wall of the compression plate 66, and the roller 23 is fixed, the roller 23 is prevented from rotating during the lifting process of the box girder 1, and the use safety is improved.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. The utility model provides a hoist for variable cross section steel-concrete composite beam which characterized in that includes:

a box girder (1);

a fixing mechanism (3);

the supporting mechanism (2) is installed inside the fixing mechanism (3), the supporting mechanism (2) comprises a steel cable (21), a fixed pulley (22), a roller (23) and a fixed seat (24), the fixed seat (24) is fixed inside the fixing mechanism (3), one end of the fixed seat (24) is rotatably connected with the roller (23), and the side wall of the roller (23) is wound on the steel cable (21); the fixed pulleys (22) are symmetrically arranged in the fixing mechanism (3), the fixed pulleys (22) are connected with the steel cable (21) in a sliding manner, and the steel cable (21) is connected with the box girder (1);

the driving mechanism (4) is fixed inside the fixing mechanism (3), the driving mechanism (4) comprises a first variable frequency motor (41), a first gear (42) and a second gear (43), the first variable frequency motor (41) is symmetrically installed inside the fixing mechanism (3), the first variable frequency motor (41) is connected with the first gear (42), the first gear (42) is meshed with the second gear (43), and the second gear (43) is fixed on the side wall of the roller (23);

the limiting mechanism (5), the limiting mechanism (5) is installed inside the fixing mechanism (3), and the limiting mechanism (5) is clamped with the roller (23);

the compression mechanism (7) is installed inside the fixing mechanism (3), and the compression mechanism (7) is rotatably connected with the limiting mechanism (5);

and the reinforcing mechanism (6) is connected with the fixed seat (24), and the reinforcing mechanism (6) is clamped with the second gear (43).

2. The lifting appliance for the variable cross-section steel-concrete composite beam according to claim 1, wherein the fixing mechanism (3) comprises a fixing box (31), a lifting ring (32) and a supporting beam (33), the fixing seat (24) is installed inside the fixing box (31), the lifting ring (32) is installed at the top end of the fixing box (31), and the supporting beam (33) is fixedly connected to the center inside the fixing box (31).

3. The lifting appliance for the variable cross-section steel-concrete composite beam according to claim 2, wherein the reinforcing mechanism (6) comprises a convex block (61), a fixed shaft (62), a sliding rod (63), a second spring (64), a fixed disc (65) and a pressing plate (66), one end of the roller (23) is fixedly connected with the fixed shaft (62), the fixed disc (65) is fixed on the side wall of the support beam (33), and the fixed disc (65) is rotatably connected with the fixed shaft (62); the fixed disc (65) is connected with a plurality of sliding rods (63) in a sliding manner, and one end of each sliding rod (63) is fixedly connected with the extrusion plate (66); the side wall of the sliding rod (63) is sleeved with the second spring (64), and the second spring (64) is fixed inside the fixed disc (65); the second gear (43), the fixed shaft (62), the sliding rod (63) and the side wall of the extrusion plate (66) are respectively provided with the lug (61), the lug (61) on the side wall of the sliding rod (63) is clamped with the lug (61) on the side wall of the second gear (43), and the lug (61) on the side wall of the fixed shaft (62) is clamped with the lug (61) on the side wall of the extrusion plate (66).

4. The lifting appliance for the variable cross-section steel-concrete composite beam according to claim 3, wherein the second gear (43) and the projection (61) on the side wall of the fixed shaft (62) are distributed in a ring shape, and the side wall of the projection (61) is in an arc-shaped structure.

5. The lifting appliance for the variable cross-section steel-concrete composite beam according to claim 3, wherein the compression mechanism (7) comprises a second variable frequency motor (71), a mounting shaft (72), a compression rod (73) and a compression block (74), the second variable frequency motor (71) is symmetrically mounted inside the support beam (33), and the second variable frequency motor (71) is connected with the mounting shaft (72); the side walls of the pressing plate (66) are equidistantly provided with the compression rods (73); the side wall of the mounting shaft (72) mounts a plurality of the compression blocks (74), and the compression blocks (74) and the compression bar (73) are slidably connected to the side wall of the compression bar (73).

6. The lifting appliance for the variable cross-section steel-concrete composite beam according to claim 5, wherein the side walls of the two ends of the compression block (74) are arc-shaped structures, and the height of the compression block (74) is equal to the longest vertical distance between the sliding rod (63) and the second gear (43).

7. The lifting appliance for the variable cross-section steel-concrete composite beam according to claim 4, wherein the limiting mechanism (5) comprises a toothed plate (51), a limiting plate (52), a rotating rod (53), a clamping plate (54), a first spring (55) and an electromagnet (56), the side wall of the roller (23) is provided with the toothed plate (51) in an annular shape, the clamping plate (54) is symmetrically arranged inside the fixed box (31), the first spring (55) is arranged between the clamping plate (54) and the rotating rod (53), and the rotating rod (53) is rotatably connected with the side wall of the fixed box (31); the bottom end of the rotating rod (53) is fixedly connected with the limiting plate (52), and the limiting plate (52) is clamped with the toothed plate (51); the side wall of the fixed seat (24) is provided with the electromagnet (56), and the electromagnet (56) adsorbs the magnetic rotating rod (53).

8. The spreader for the variable cross-section steel-concrete composite beam according to claim 7, wherein the toothed plate (51) and the second gear (43) are respectively located at both sides of the drum (23), and the diameter of the second gear (43) is greater than that of the first gear (42).