Concrete precast box girder hoisting device and hoisting method

Abstract

The application discloses a concrete prefabricated box girder hoisting device and a hoisting method, relates to the technical field of prefabricated box girder installation, and the concrete prefabricated box girder hoisting device comprises a lifting appliance, a plurality of strip-shaped holes are formed in the lifting appliance, two clamping jaws are slidably connected in the strip-shaped holes in a facing direction or a reverse direction, and a driving assembly for driving the two clamping jaws to move is arranged on the top of the lifting appliance; the driving assembly comprises a fixing frame arranged on the top of the lifting appliance, a guide rod fixed to the fixing frame and a double-threaded lead screw rotationally connected to the fixing frame; the two clamping jaws are slidably connected to the guide rod, and the two clamping jaws are threadedly connected to the two ends of the double-threaded lead screw respectively; a driving motor is arranged at one end of the fixing frame, and the output shaft of the driving motor is fixed to one end of the double-threaded lead screw. The application can reduce the possibility that the prefabricated box girder slips off when being hoisted.

Description

Technical Field

[0001] This application relates to the technical field of precast box girder installation, and in particular to a precast concrete box girder hoisting device and hoisting method. Background Technology

[0002] Currently, box girders are a type of beam used in bridge engineering. They are hollow inside with flanges on both sides of the upper part, resembling a box, hence the name. They are classified as single-box or multi-box girders. Reinforced concrete box girders are divided into precast box girders and cast-in-place box girders.

[0003] In related technologies, the hoisting of precast box girders generally adopts the steel rope bottom hoisting method, which means that a pair of circular steel ropes are used to hold the two ends of the box girder respectively, and then it is lifted.

[0004] However, the precast box girders are prone to slipping during hoisting, which poses a certain safety risk. Summary of the Invention

[0005] To reduce the possibility of slippage during hoisting of precast box girders, this application provides a hoisting device for precast concrete box girders, employing the following technical solution: A precast concrete box girder hoisting device includes a lifting device with a strip-shaped hole inside. Two grippers are slidably connected to each other or back to back within the strip-shaped hole. A drive assembly for moving the two grippers is installed on the top of the lifting device. The drive assembly includes a fixed frame installed on the top of the lifting device, a guide rod fixed to the fixed frame, and a double-threaded screw rotatably connected to the fixed frame. Both grippers are slidably connected to the guide rod and threadedly connected to both ends of the double-threaded screw. A drive motor is installed at one end of the fixed frame, and the output shaft of the drive motor is fixedly connected to one end of the double-threaded screw.

[0006] Preferably, the precast box girder has precast holes, and a first through hole is provided on one side of the strip hole. A vertical plate is slidably connected in the first through hole, and the vertical plate can pass through the precast hole. A second through hole is provided at the bottom of the vertical plate. Two limiting blocks are slidably connected in the second through hole. A first inclined surface is provided on the side of the limiting block near the first through hole. A transmission mechanism for driving the limiting blocks to move is installed in the second through hole. A driving mechanism for driving the vertical plate to move upward is installed in the strip hole. A reset mechanism for resetting the vertical plate is installed on the side wall of the first through hole.

[0007] Preferably, the transmission mechanism includes two first slide grooves formed on one side of the second through hole, first sliders respectively slidably connected to the two first slide grooves, and two first springs respectively fixed to one side of the two first sliders; the two first sliders are respectively fixed to two limiting blocks; the end of the first spring away from the first slider is fixed to the inner wall of one end of the first slide groove; a first electric push rod is installed in each first slide groove, and the piston rod of the first electric push rod abuts against the side of the first slider away from the first spring.

[0008] Preferably, the driving mechanism includes two push rods slidably connected to the strip hole, and the two push rods are respectively fixed to the opposite inner sides of the two grippers; connecting blocks are respectively fixed to both sides of the vertical plate, and the two connecting blocks are slidably connected to the strip hole. The two connecting blocks are correspondingly arranged with the two push rods, and the opposite inner sides of the push rods and the connecting blocks are respectively provided with a second inclined surface, and the two second inclined surfaces match each other.

[0009] Preferably, the reset mechanism includes a second slide groove formed on the side wall of the first through hole, a second slider slidably connected to the second slide groove, and a second spring fixed to one side of the second slider; the second slider is fixed to one side of the vertical plate, and the end of the second spring away from the second slider is fixed to the inner wall of one end of the second slide groove; the elastic force of the second spring is much greater than that of the first spring.

[0010] Preferably, a brake block is fixed to the top of the vertical plate, and the end of the brake block away from the vertical plate can abut against the side wall of the double-threaded screw.

[0011] Preferably, a limiting mechanism for preventing the double-threaded lead screw from reversing is installed inside the strip-shaped hole.

[0012] Preferably, the limiting mechanism includes a third slide groove formed on the side wall of the strip hole, a limiting plate slidably connected to the third slide groove, a fourth slide groove formed on the side wall of the third slide groove, a third slider slidably connected to the fourth slide groove, and a third spring fixed to one side of the third slider; the third slider is fixed to one side of the limiting plate, and the end of the third spring away from the third slider is fixed to the inner wall of one end of the fourth slide groove; a limiting groove is formed on one side of the push rod, and a third inclined surface is provided on the side of the limiting plate near the limiting groove, and the limiting plate is inserted into the limiting groove; a transmission component for separating the limiting plate from the limiting groove is installed on the side of the third slide groove away from the fourth slide groove.

[0013] Preferably, the transmission component includes a fifth slide groove formed on the side of the third slide groove away from the fourth slide groove, a second electric push rod installed in the fifth slide groove, and a pull rod fixed to the second electric push rod; a protrusion is fixedly connected to the side of the limiting plate away from the third slide block, and the pull rod abuts against one side of the protrusion.

[0014] On the other hand, this application provides a hoisting method for a precast concrete box girder hoisting device, which adopts the following technical solution: A method for hoisting a precast concrete box girder includes the following steps: First, a crane drives a lifting device to move, causing a vertical plate to be inserted into a precast hole under the weight of the lifting device. At this time, a limiting block moves into a second through hole under the action of a first inclined surface. The movement of the limiting block into the second through hole drives a first slider to move, and the movement of the first slider presses against a first spring. After the lifting device is placed on top of the precast box girder, the first slider drives the limiting block to move out of the second through hole under the action of the first spring. Then, the drive motor is started. The output shaft of the drive motor drives a double-threaded screw to rotate. The rotation of the double-threaded screw drives two grippers to move towards each other, and the two grippers can clamp the precast box girder. In addition, the two grippers... The opposing movement causes the push rods to move in opposite directions. Then, under the action of the second inclined plane, the push rods drive the vertical plate to move upward. The upward movement of the vertical plate drives the limiting block to move upward. The upward movement of the limiting block allows it to abut against the top wall of the precast box girder's inner cavity, thus improving the stability of the precast box girder during hoisting. Furthermore, when the gripper drives the push rod, the push rod drives the limiting plate to move upward under the action of the third inclined plane. The upward movement of the limiting plate drives the third slider to move upward. The upward movement of the third slider presses against the third spring. When the push rod moves to the appropriate position, the third slider, under the action of the third spring, drives the limiting plate to engage with the limiting groove. This limits the push rod, thereby reducing the possibility of slippage during hoisting of the precast box girder.

[0015] In summary, this application has the following beneficial effects: 1. First, the lifting device is moved by a crane, so that the vertical plate is inserted into the precast hole under the weight of the lifting device. At this time, the limiting block moves into the second through hole under the action of the first inclined surface. The movement of the limiting block into the second through hole drives the first slider to move. The movement of the first slider presses against the first spring. When the lifting device is placed on the top of the precast box girder, the first slider drives the limiting block to move out of the second through hole under the action of the first spring. Then, the drive motor is started. At this time, the output shaft of the drive motor drives the double threaded screw to rotate. The rotation of the double threaded screw drives the two jaws to move towards each other. The movement of the two jaws towards each other can clamp the precast box girder. In addition, the movement of the two jaws towards each other drives the push rod to move towards each other. Then the push rod... The second inclined plane drives the vertical plate to move upward, which in turn moves the limiting block upward. The limiting block then abuts against the top wall of the precast box girder's inner cavity, thus improving the stability of the precast box girder during hoisting. Furthermore, when the gripper drives the push rod, the push rod, under the action of the third inclined plane, drives the limiting plate upward. The upward movement of the limiting plate then drives the third slider upward, which in turn presses against the third spring. When the push rod moves to the appropriate position, the third slider, under the action of the third spring, drives the limiting plate to engage with the limiting groove, thus limiting the push rod. In summary, by adopting the above scheme, the possibility of slippage during hoisting of the precast box girder can be reduced. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application; Figure 2 This is a cross-sectional view used to show the internal structure of the lifting device in the embodiments of this application; Figure 3 This is a cross-sectional view used to show the transmission mechanism in an embodiment of this application; Figure 4 This is a cross-sectional view used to show the limiting mechanism in the embodiments of this application.

[0017] Explanation of reference numerals in the attached drawings: 1. Lifting device; 11. Strip hole; 12. Gripper; 13. First through hole; 14. Vertical plate; 141. Second through hole; 15. Limiting block; 151. First inclined surface; 2. Drive assembly; 21. Fixing frame; 22. Guide rod; 23. Double threaded screw; 24. Drive motor; 3. Precast box girder; 31. Precast hole; 4. Transmission mechanism; 41. First slide groove; 42. First slider; 43. First spring; 44. First electric push rod; 5. Drive 51. Moving mechanism; 52. Push rod; 53. Connecting block; 54. Second inclined plane; 6. Reset mechanism; 61. Second slide groove; 62. Second slider; 63. Second spring; 7. Brake block; 8. Limiting mechanism; 81. Third slide groove; 82. Limiting plate; 82. Third inclined plane; 83. Fourth slide groove; 84. Third slider; 85. Third spring; 86. Limiting groove; 9. Transmission component; 91. Fifth slide groove; 92. Second electric push rod; 93. Pull rod; 94. Protrusion. Detailed Implementation

[0018] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0019] Identical parts are indicated by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," "lower," "bottom," and "top" used in the following description refer to directions in the accompanying drawings, while the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific part, respectively.

[0020] This application discloses a hoisting device for precast concrete box girders, including a hoisting device 1. The hoisting device 1 has a strip-shaped hole 11. Two grippers 12 are slidably connected to each other or back to back along the width direction of the hoisting device 1 within the strip-shaped hole 11. A drive assembly 2 for driving the two grippers 12 to move is installed on the top of the hoisting device 1. The drive assembly 2 includes a fixed frame 21 installed on the top of the hoisting device 1, a guide rod 22 horizontally fixed to the fixed frame 21, and a double-threaded screw 23 horizontally rotatably connected to the fixed frame 21 through a bearing. Both grippers 12 are slidably connected to the guide rod 22, and the two grippers 12 are respectively threaded to both ends of the double-threaded screw 23. A drive motor 24 is installed at one end of the fixed frame 21, and the output shaft of the drive motor 24 is fixedly connected to one end of the double-threaded screw 23. When it is necessary to hoist the precast box girder 3, the hoisting device 1 is first moved by the crane to place it on top of the precast box girder 3. Then, the drive motor 24 is started. At this time, the output shaft of the drive motor 24 drives the double threaded screw 23 to rotate. The rotation of the double threaded screw 23 drives the two jaws 12 to move towards each other. The two jaws 12 moving towards each other can clamp the precast box girder 3, and then the precast box girder 3 can be hoisted. In summary, by using two jaws 12, the possibility of the precast box girder 3 slipping during hoisting can be reduced.

[0021] The precast box girder 3 has precast holes 31. A first through hole 13 is provided on one side of the strip hole 11. A vertical plate 14 is slidably connected in the first through hole 13, and the vertical plate 14 can pass through the precast hole 31. A second through hole 141 is provided at the bottom of the vertical plate 14. Two limiting blocks 15 are slidably connected in the second through hole 141. A first inclined surface 151 is provided on the side of the limiting block 15 near the first through hole 13. A transmission mechanism 4 for driving the limiting block 15 to move is installed in the second through hole 141. A driving mechanism 5 for driving the vertical plate 14 to move upward is installed in the strip hole 11. A reset mechanism 6 for resetting the vertical plate 14 is installed on the side wall of the first through hole 13. First, the lifting device 1 is moved by the crane and placed on the top of the precast box girder 3. At this time, the vertical plate 14 passes through the precast hole 31. Then, the limiting block 15 is moved outward through the second through hole 141 by the transmission mechanism 4. Next, the vertical plate 14 is moved upward by the driving mechanism 5. The upward movement of the vertical plate 14 drives the limiting block 15 to move upward. This allows the limiting block 15 to abut against the top wall of the inner cavity of the precast box girder 3, thereby further reducing the possibility of the precast box girder 3 slipping.

[0022] The transmission mechanism 4 includes two first slide grooves 41 opened on one side of the second through hole 141, first sliders 42 respectively slidably connected to the two first slide grooves 41, and two first springs 43 respectively fixed to one side of the two first sliders 42; the two first sliders 42 are respectively fixed to two limiting blocks 15; the end of the first spring 43 away from the first slider 42 is fixed to the inner wall of one end of the first slide groove 41; a first electric push rod 44 is installed in each first slide groove 41, and the piston rod of the first electric push rod 44 abuts against the side of the first slider 42 away from the first spring 43. Under the action of its first inclined surface 151, the limiting block 15 will move into the second through hole 141 when it contacts the precast hole 31 and the side wall of the first through hole 13. At this time, the limiting block 15 drives the first slider 42 to move, and the movement of the first slider 42 presses against the first spring 43. When the bottom of the vertical plate 14 extends into the cavity of the precast box girder 3, the first slider 42 drives the limiting block 15 to move out of the second through hole 141 under the action of the first spring 43, which facilitates the vertical plate 14 to limit the precast box girder 3. When it is necessary to move the limiting block 15 into the second through hole 141, the first electric push rod 44 is activated first. At this time, the piston rod of the first electric push rod 44 drives the first slider 42 to move, and the movement of the first slider 42 can drive the limiting block 15 to move into the second through hole 141.

[0023] The driving mechanism 5 includes two push rods 51 that slide along the width direction of the lifting device 1 and are connected to the strip hole 11. The two push rods 51 are respectively fixed to the opposite inner sides of the two grippers 12. Connecting blocks 52 are fixed to both sides of the vertical plate 14. Both connecting blocks 52 slide vertically and are connected to the strip hole 11. The two connecting blocks 52 are correspondingly arranged with the two push rods 51. The opposite inner sides of the push rods 51 and the connecting blocks 52 are respectively provided with second inclined surfaces 53, and the two second inclined surfaces 53 match. The two grippers 12 move towards each other, causing the push rods 51 to move towards each other. Then, under the action of the second inclined surfaces 53, the push rods 51 drive the vertical plate 14 to move upward.

[0024] The reset mechanism 6 includes a second slide groove 61 vertically formed on the side wall of the first through hole 13, a second slider 62 vertically slidably connected to the second slide groove 61, and a second spring 63 fixed to one side of the second slider 62. The second slider 62 is fixed to one side of the vertical plate 14, and the second spring 63 is vertically arranged, with one end of the second spring 63 away from the second slider 62 fixed to the inner wall of one end of the second slide groove 61. The elastic force of the second spring 63 is much greater than that of the first spring 43. When the vertical plate 14 moves upward, it drives the second slider 62 to move upward, and the upward movement of the second slider 62 presses against the second spring 63. When the push rod 51 separates from the connecting block 52, the second slider 62 drives the vertical plate 14 to reset under the action of the second spring 63. The reset mechanism 6 facilitates the reset of the vertical plate 14.

[0025] A brake block 7 is fixedly connected to the top of the vertical plate 14. The end of the brake block 7 away from the vertical plate 14 can abut against the side wall of the double threaded screw 23. The vertical plate 14 moves upward under the action of the push rod 51. The upward movement of the push rod 51 drives the brake block 7 to move upward. When the brake block 7 abuts against the double threaded screw 23, it means that the gripper 12 has clamped the precast box girder 3. If the drive motor 24 continues to rotate at this time, the brake block 7 can brake the double threaded screw 23, thereby reducing the possibility of the precast box girder 3 being damaged by the gripper 12.

[0026] A limiting mechanism 8 for preventing the double-threaded lead screw 23 from reversing is installed inside the slot 11. The limiting mechanism 8 includes a third slide groove 81 vertically formed on the side wall of the slot 11, a limiting plate 82 vertically slidably connected to the third slide groove 81, a fourth slide groove 83 vertically formed on the side wall of the third slide groove 81, a third slider 84 vertically slidably connected to the fourth slide groove 83, and a third spring 85 fixed to one side of the third slider 84; the third slider 84 is fixed to the limiting plate 85. On one side of the position plate 82, the third spring 85 is vertically arranged, and the end of the third spring 85 away from the third slider 84 is fixed to the inner wall of one end of the fourth slide groove 83; a limit groove 86 is opened on one side of the push rod 51, and a third inclined surface 821 is provided on the side of the limit plate 82 near the limit groove 86, and the limit plate 82 is inserted into the limit groove 86; a transmission component 9 for separating the limit plate 82 from the limit groove 86 is installed on the side of the third slide groove 81 away from the fourth slide groove 83. When the gripper 12 drives the push rod 51, the push rod 51 drives the limiting plate 82 to move upward under the action of the third inclined surface 821. The upward movement of the limiting plate 82 drives the third slider 84 to move upward. The upward movement of the third slider 84 presses against the third spring 85. When the push rod 51 moves to the appropriate position, the third slider 84 drives the limiting plate 82 to engage with the limiting groove 86 under the action of the third spring 85. This can limit the push rod 51 and prevent the double threaded screw 23 from reversing.

[0027] The transmission component 9 includes a fifth slide groove 91 vertically formed on the side of the third slide groove 81 away from the fourth slide groove 83, a second electric push rod 92 vertically installed in the fifth slide groove 91, and a pull rod 93 fixedly connected to the second electric push rod 92; a protrusion 94 is fixedly connected to the side of the limiting plate 82 away from the third slider 84, and the pull rod 93 abuts against one side of the protrusion 94. When it is necessary to separate the limiting plate 82 from the limiting groove 86, the second electric push rod 92 is first closed. At this time, the piston rod of the second electric push rod 92 drives the pull rod 93 to move upward. The upward movement of the pull rod 93 drives the protrusion 94 to move upward. The upward movement of the protrusion 94 drives the limiting plate 82 to move upward. The upward movement of the limiting plate 82 can separate the limiting plate 82 from the limiting groove 86. The transmission component 9 facilitates the separation of the limiting plate 82 from the limiting groove 86.

[0028] This application discloses a hoisting method for a precast concrete box girder hoisting device, comprising the following steps: First, a crane drives a lifting device 1 to move, causing a vertical plate 14 to be inserted into a precast hole 31 under the weight of the lifting device 1. At this time, a limiting block 15 moves into a second through hole 141 under the action of a first inclined surface 151. The movement of the limiting block 15 into the second through hole 141 drives the first slider 42 to move. The movement of the first slider 42 presses against the first spring 43. After the lifting device 1 is placed on top of the precast box girder 3, the first slider 42 drives the limiting block 15 to move out of the second through hole 141 under the action of the first spring 43. Then, the drive motor 24 is started. At this time, the output shaft of the drive motor 24 drives a double threaded screw 23 to rotate. The rotation of the double threaded screw 23 drives two grippers 12 to move towards each other. The movement of the two grippers 12 towards each other can lift the precast box girder. The box girder 3 is clamped; in addition, the two grippers 12 move towards each other, causing the push rod 51 to move towards each other. Then, under the action of the second inclined surface 53, the push rod 51 drives the vertical plate 14 to move upward. The upward movement of the vertical plate 14 drives the limiting block 15 to move upward. The upward movement of the limiting block 15 can abut against the top wall of the inner cavity of the precast box girder 3, which can improve the stability of the precast box girder 3 during hoisting. Furthermore, when the grippers 12 drive the push rod 51, the push rod 51 drives the limiting plate 82 to move upward under the action of the third inclined surface 821. The upward movement of the limiting plate 82 drives the third slider 84 to move upward. The upward movement of the third slider 84 presses against the third spring 85. When the push rod 51 moves to the appropriate position, the third slider 84 drives the limiting plate 82 to insert into the limiting groove 86 under the action of the third spring 85, which can limit the push rod 51.

[0029] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A hoisting device for precast concrete box girders, comprising a hoisting tool (1), characterized in that: The lifting device (1) has a strip-shaped hole (11) inside, and two grippers (12) are slidably connected to each other or back to back inside the strip-shaped hole (11). A drive assembly (2) for driving the two grippers (12) to move is installed on the top of the lifting device (1). The precast box girder (3) has precast holes (31). A first through hole (13) is provided on one side of the strip hole (11). A vertical plate (14) is slidably connected in the first through hole (13) along the vertical direction. The vertical plate (14) can pass through the precast hole (31). A second through hole (141) is provided at the bottom of the vertical plate (14). Two limiting blocks (15) are slidably connected in the second through hole (141). A first inclined surface (151) is provided on the side of the limiting block (15) near the first through hole (13). A transmission mechanism (4) for driving the limiting block (15) to move is installed in the second through hole (141). A driving mechanism (5) for driving the vertical plate (14) to move upward is installed in the strip hole (11). A reset mechanism (6) for resetting the vertical plate (14) is installed on the side wall of the first through hole (13). The transmission mechanism (4) includes two first slide grooves (41) opened on one side of the second through hole (141), first sliders (42) slidably connected to the two first slide grooves (41) respectively, and two first springs (43) fixed to one side of the two first sliders (42) respectively; the two first sliders (42) are fixed to two limiting blocks (15) respectively; the end of the first spring (43) away from the first slider (42) is fixed to the inner wall of one end of the first slide groove (41); a first electric push rod (44) is installed in each first slide groove (41), and the piston rod of the first electric push rod (44) abuts against the side of the first slider (42) away from the first spring (43); The driving mechanism (5) includes two push rods (51) slidably connected to the strip hole (11), and the two push rods (51) are respectively fixed to the opposite inner sides of the two grippers (12); the two sides of the vertical plate (14) are respectively fixed to connecting blocks (52), and the two connecting blocks (52) are slidably connected to the strip hole (11). The two connecting blocks (52) are correspondingly arranged with the two push rods (51), and the opposite inner sides of the push rods (51) and the connecting blocks (52) are respectively provided with second inclined surfaces (53), and the two second inclined surfaces (53) match each other.

2. The concrete precast box girder hoisting device according to claim 1, characterized in that: The drive assembly (2) includes a fixed frame (21) mounted on the top of the lifting device (1), a guide rod (22) fixed to the fixed frame (21), and a double-threaded screw (23) rotatably connected to the fixed frame (21); both grippers (12) are slidably connected to the guide rod (22), and the two grippers (12) are threaded to both ends of the double-threaded screw (23); a drive motor (24) is mounted on one end of the fixed frame (21), and the output shaft of the drive motor (24) is fixed to one end of the double-threaded screw (23).

3. The concrete precast box girder hoisting device according to claim 1, characterized in that: The reset mechanism (6) includes a second slide groove (61) opened on the side wall of the first through hole (13), a second slider (62) slidably connected to the second slide groove (61), and a second spring (63) fixed to one side of the second slider (62); the second slider (62) is fixed to one side of the vertical plate (14), and the end of the second spring (63) away from the second slider (62) is fixed to the inner wall of one end of the second slide groove (61); the elastic force of the second spring (63) is much greater than the elastic force of the first spring (43).

4. The concrete precast box girder hoisting device according to claim 1, characterized in that: A brake block (7) is fixedly connected to the top of the vertical plate (14), and the end of the brake block (7) away from the vertical plate (14) can abut against the side wall of the double threaded screw (23).

5. The concrete precast box girder hoisting device according to claim 1, characterized in that: A limiting mechanism (8) for preventing the double-threaded screw (23) from reversing is installed inside the strip hole (11).

6. The concrete precast box girder hoisting device according to claim 5, characterized in that: The limiting mechanism (8) includes a third slide groove (81) formed on the side wall of the slot (11), a limiting plate (82) slidably connected to the third slide groove (81), a fourth slide groove (83) formed on the side wall of the third slide groove (81), a third slider (84) slidably connected to the fourth slide groove (83), and a third spring (85) fixed to one side of the third slider (84); the third slider (84) is fixed to one side of the limiting plate (82), and the third spring (85) is far from the limiting plate (82). One end of the third slider (84) is fixed to the inner wall of one end of the fourth slide groove (83); a limiting groove (86) is provided on one side of the push rod (51), and a third inclined surface (821) is provided on the side of the limiting plate (82) near the limiting groove (86), and the limiting plate (82) is inserted into the limiting groove (86); a transmission component (9) for separating the limiting plate (82) from the limiting groove (86) is installed on the side of the third slide groove (81) away from the fourth slide groove (83).

7. The concrete precast box girder hoisting device according to claim 6, characterized in that: The transmission component (9) includes a fifth slide (91) opened on the side of the third slide (81) away from the fourth slide (83), a second electric push rod (92) installed in the fifth slide (91), and a pull rod (93) fixed to the second electric push rod (92); a protrusion (94) is fixed on the side of the limiting plate (82) away from the third slider (84), and the pull rod (93) abuts against one side of the protrusion (94).

8. A hoisting method for a precast concrete box girder hoisting device, based on any one of claims 1-7, characterized in that: Includes the following steps: First, the lifting device (1) is moved by a crane, so that the vertical plate (14) is inserted into the precast hole under the gravity of the lifting device (1). At this time, the limiting block (15) moves into the second through hole (141) under the action of the first inclined surface (151). The movement of the limiting block (15) into the second through hole (141) drives the first slider (42) to move. The movement of the first slider (42) presses against the first spring (43). When the lifting device (1) is placed on the top of the precast box girder (3), the first spring (43) is then in place. A slider (42) drives the limiting block (15) to move out of the second through hole (141) under the action of the first spring (43); then the drive motor (24) is started. At this time, the output shaft of the drive motor (24) drives the double threaded screw (23) to rotate. The rotation of the double threaded screw (23) drives the two grippers (12) to move towards each other. The two grippers (12) moving towards each other can clamp the precast box girder (3); in addition, the two grippers (12) moving towards each other drive the push rod (51) to move towards each other. The push rod (51) moves upward, and then the push rod (51) drives the vertical plate (14) to move upward under the action of the second inclined plane (53). The upward movement of the vertical plate (14) drives the limiting block (15) to move upward. The upward movement of the limiting block (15) can abut against the top wall of the inner cavity of the precast box girder (3), which can improve the stability of the precast box girder (3) during hoisting. Furthermore, when the gripper (12) drives the push rod (51), the push rod (51) drives the limiting plate (82) under the action of the third inclined plane (821). The push rod (51) moves upward, and the limiting plate (82) moves upward, driving the third slider (84) to move upward. The third slider (84) moves upward and presses against the third spring (85). When the push rod (51) moves to the appropriate position, the third slider (84) drives the limiting plate (82) to insert into the limiting groove (86) under the action of the third spring (85). This can limit the push rod (51) and reduce the possibility of the precast box girder (3) slipping during hoisting.

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