A prefabricated box girder hydraulic formwork device

Abstract

This invention relates to the field of precast box girder casting technology, specifically to a hydraulic formwork device for precast box girders. An inner mold is located at the center of the side molds on both sides above the base. A drive shaft is rotatably supported in the core cavity of the inner mold by multiple support frames. At least four hydraulic cylinders are arranged in a circumferential array on the outer ring of the drive shaft. Multiple positioning slots are provided on both the upper and lower templates of the inner mold, and a contact groove is provided on the outer side of each positioning slot. Positioning plates are fixed to the piston rod ends of the multiple hydraulic cylinders. Friction plates are provided on the outer surface of each positioning plate, and the friction plates are inserted and aligned with the contact grooves. The outer surfaces of two symmetrical friction plates are smooth, while contact balls are rotatably arranged on the outer surfaces of the other two symmetrical friction plates. This invention can reduce the friction generated when the inner mold is pulled out of the precast box girder, thereby reducing the power output of the winch when pulling out the inner mold.

Description

Technical Field

[0001] This invention relates to the field of precast box girder casting technology, specifically to a hydraulic formwork device for precast box girders. Background Technology

[0002] 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. Precast box girders are widely used because they are cast in an independent site and then erected using a bridge erecting machine after the substructure is completed, which can accelerate the project progress and save construction time.

[0003] Currently, bridge box girders are prefabricated using formwork. Before pouring concrete, the formwork needs to be assembled, and after pouring concrete, the formwork needs to be disassembled. However, the existing methods for pulling the inner formwork out of the prefabricated box girder mostly involve using a winch to fix a steel wire rope to the end of the inner formwork, and then pulling the inner formwork out of the prefabricated box girder by the continuous rotation of the winch. Since the outer surface of the inner formwork is in direct contact with the inner wall of the prefabricated box girder, and the concrete also exerts a certain adhesive force on the inner formwork when it solidifies, a large frictional force will inevitably be generated when the inner formwork is pulled out of the prefabricated box girder. This requires increasing the output power of the winch to pull the inner formwork out of the prefabricated box girder stably, thus affecting the efficiency of pulling the inner formwork out of the prefabricated box girder. Summary of the Invention

[0004] The purpose of this invention is to provide a hydraulic formwork device for precast box girders to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a hydraulic formwork device for precast box girders, comprising a base, side molds, a hydraulic lifting system and a propulsion system, wherein an inner mold is provided at the center of the side molds located above the base and on both sides, and an auxiliary release mechanism is provided in the core cavity of the inner mold, the auxiliary release mechanism being used to assist in pulling the inner mold, which is pulled by a traction rope, out horizontally from the cast box girder.

[0006] Preferably, the auxiliary release mechanism includes a drive shaft, a support frame, hydraulic cylinders, positioning plates, friction plates, and contact balls. The drive shaft is rotatably supported in the core cavity of the inner mold by multiple support frames, and one end of the drive shaft is connected to the output shaft of a drive motor fixed on the support frame. The outer circumferential surface of the drive shaft has at least four hydraulic cylinders, and each set of hydraulic cylinders in the circumferential array is arranged along the length direction of the drive shaft. Multiple positioning square slots are provided on the upper and lower templates of the inner mold, and a contact through slot is provided on the outer side of each positioning square slot. The size of the contact through slot is smaller than the size of the positioning square slot. Positioning plates are fixed to the piston rod end faces of multiple hydraulic cylinders, and the positioning plates are slidably inserted and aligned with the positioning square slots. A friction plate is provided on the outer side of each positioning plate, and the friction plate is inserted and aligned with the contact through slot. The outer side of two symmetrical friction plates is a smooth surface, and the outer side of the other two symmetrical friction plates has multiple rotating slots, and a contact ball is rotatably arranged in each rotating slot. The outer side of the multiple contact balls is flush with the upper and lower outer sides of the inner mold.

[0007] Preferably, the friction plate with the rotating groove has a lubricating oil cavity inside, and the lubricating oil cavity is filled with lubricating oil, and the lubricating oil cavity is connected to multiple rotating grooves.

[0008] Preferably, the inner diameter of the rotating groove is larger than the outer diameter of the contact ball, and one-third of the outer spherical surface of the contact ball extends out of the rotating groove. The contact ball is elastically slidably disposed in the rotating groove by a rotating contact spring, and the other end of the spring is connected to the lubricating oil cavity.

[0009] Preferably, an elastic sealing frame is fixedly fitted around the outer ring of the friction plate, which has a smooth outer surface, and the elastic sealing frame is elastically squeezed and inserted into the contact groove.

[0010] Preferably, the surface of the friction plate, which has a smooth outer surface, is coated with a release agent.

[0011] Compared with the prior art, the beneficial effects of the present invention are:

[0012] 1. This invention provides an auxiliary release mechanism within the core cavity of the inner mold. When the inner mold is inserted into the reinforcing cage, a friction plate with a smooth outer surface is inserted vertically into the contact grooves of the upper and lower templates of the inner mold, thereby sealing the core cavity of the inner mold. When the inner mold needs to be pulled out of the precast box girder, a friction plate with rolling contact balls on its outer surface is inserted into the contact groove, allowing the outer surfaces of the upper and lower templates of the inner mold to generate rolling friction with the precast box girder. This reduces the friction force generated when the inner mold is pulled out of the precast box girder, thereby reducing the power output of the winch when pulling out the inner mold.

[0013] 2. This invention connects the lubricating oil cavity within the friction plate to the rotating groove, and the contact ball is elastically supported within the rotating groove by a spring. When the contact ball contacts the precast box girder and generates extrusion force, the outer ring of the contact ball contracts into the lubricating oil cavity. At this time, a gap is created between the contact ball and the rotating groove, allowing the lubricating oil in the lubricating oil cavity to enter the contact surface between the inner mold and the precast box girder through the gap between the rotating groove and the contact ball. This further reduces the friction between the inner mold and the precast box girder, making it easier for the inner mold to be quickly pulled out of the precast box girder by the wire rope of the winch without causing any safety hazards. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the present invention;

[0015] Figure 2 This is a schematic diagram of the auxiliary disengagement mechanism of the present invention;

[0016] Figure 3 This is a cross-sectional view of the friction plate of the present invention;

[0017] Figure 4 For the present invention Figure 3 Enlarged view of a portion of point A in the middle.

[0018] In the diagram: 1. Base; 2. Side mold; 3. Inner mold; 31. Positioning square groove; 32. Contact through groove; 4. Auxiliary release mechanism; 41. Drive shaft; 42. Support frame; 43. Hydraulic cylinder; 44. Positioning plate; 45. Friction plate; 451. Rotating groove; 452. Lubricating oil cavity; 46. Contact ball; 5. Spring; 6. Elastic sealing frame. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1:

[0021] like Figures 1 to 4As shown, this invention provides a technical solution for a hydraulic formwork device for precast box girders: It includes a base 1, side molds 2, a hydraulic lifting system, and a propulsion system. An inner mold 3 is located at the center of the side molds 2, which are situated above the base 1 on both sides. An auxiliary release mechanism 4 is installed in the core cavity of the inner mold 3. This auxiliary release mechanism 4 is used to assist in pulling the inner mold 3, pulled by a traction rope, out horizontally from the cast box girder. During operation, when the inner mold 3 needs to be inserted into the reinforcing cage placed between the base 1 and the side molds 2, the construction workers pull the inner mold 3 into the reinforcing cage using a traction wire. Then, the tied reinforcing mesh is laid flat on top of the inner mold 3, and the construction workers pour concrete to form the precast box girder. After the poured concrete has solidified, the construction workers need to pull the inner mold 3 out of the precast box girder. Currently, most methods for pulling the inner mold 3 out of the precast box girder use a winch to fix a wire rope to the end of the inner mold 3, and then pull it out using the winch's... The inner mold 3 is pulled out of the precast box girder by the rotation. However, since the outer surface of the inner mold 3 is in direct contact with the inner wall of the precast box girder, and the concrete also exerts a certain adhesive force on the inner mold 3 when it solidifies, a large frictional force will inevitably be generated when the inner mold 3 is pulled out of the precast box girder. Therefore, it is necessary to increase the output power of the winch to pull the inner mold 3 out of the precast box girder stably, thus affecting the efficiency of pulling the inner mold 3 out of the precast box girder. Therefore, this invention sets an auxiliary release mechanism 4 in the core cavity of the inner mold 3. When it is necessary to pull the inner mold 3 out of the precast box girder, the auxiliary release mechanism 4 works, so that the upper and lower outer surfaces of the inner mold 3 roll and rub against the inner wall of the precast box girder. This reduces the direct frictional force between the outer surface of the inner mold 3 and the inner wall of the precast box girder, so that the winch can quickly pull the inner mold 3 out of the precast box girder even in a low power output state. This makes it easier to transfer the pulled-out inner mold 3 to the next base 1 for the casting and molding of the precast box girder.

[0022] In one embodiment of the present invention, the auxiliary release mechanism 4 includes a drive shaft 41, a support frame 42, a hydraulic cylinder 43, a positioning plate 44, a friction plate 45, and a contact ball 46. The drive shaft 41 is rotatably supported in the core cavity of the inner mold 3 by multiple support frames 42, and one end of the drive shaft 41 is connected to the output shaft of a drive motor fixed on the support frame 42. At least four hydraulic cylinders 43 are arranged in a circumferential array on the outer ring surface of the drive shaft 41, and the hydraulic cylinders 43 in each circumferential array are arranged along the length direction of the drive shaft 41. Multiple positioning square grooves are provided on the upper and lower templates of the inner mold 3. 31, and each positioning square groove 31 has a contact groove 32 on its outer side. The size of the contact groove 32 is smaller than the size of the positioning square groove 31. The piston rod end faces of the plurality of hydraulic cylinders 43 are fixed with positioning plates 44, and the positioning plates 44 are slidably inserted and aligned with the positioning square grooves 31. Each positioning plate 44 has a friction plate 45 on its outer side, and the friction plate 45 is inserted and aligned with the contact groove 32. The outer sides of two symmetrical friction plates 45 are smooth, and the outer sides of the other two symmetrical friction plates 45 have a plurality of rotating grooves 451, and each rotating groove 451 is provided with a rotating groove 451. Each of the moving grooves 451 is equipped with a contact ball 46 that rotates within it. The outer surfaces of the contact balls 46 are flush with the upper and lower outer surfaces of the inner mold 3. During operation, when the inner mold 3 needs to be pulled into the reinforcing cage, the drive motor is activated to rotate the drive shaft 41 and the symmetrical hydraulic cylinders 43. At this time, the two symmetrical friction plates 45 with smooth outer surfaces are rotated to the symmetrical positioning square grooves 31 and contact through grooves 32. Then, the piston rod of the hydraulic cylinder 43 is extended, causing the positioning plate 44 and the friction plates 45 with smooth outer surfaces to insert into the positioning square grooves 31 and contact through grooves 32. Inside the through groove 32, the outer surface of the friction plate 45 is flush with the outer sides of the upper and lower templates of the inner mold 3, thus enabling the friction plate 45 to seal the contact through groove 32 of the upper and lower templates of the inner mold 3. At this time, the two friction plates 45 with contact balls 46 on their outer sides will retract into the core cavity of the inner mold 3. After the friction plate 45 with a smooth outer surface is sealed to the upper and lower templates of the inner mold 3, the construction workers will pull the inner mold 3 into the wire cage using the wire rope of the winch. Then, the construction workers will pour concrete onto the fixed side mold 2 and inner mold 3, and after solidification, it will form a precast box girder.When the inner mold 3 needs to be pulled out of the solidified precast box girder, the construction worker controls the piston rod of the hydraulic cylinder 43 below the friction plate 45 inserted into the contact groove 32 to retract. The retraction of the piston rod will cause the positioning plate 44 and the friction plate 45 to disengage from the positioning square groove 31 and the contact groove 32, respectively. Then, the drive shaft 41 is controlled to rotate, causing the friction plate 45, whose outer side is equipped with contact balls 46, to rotate to the positioning square groove 31 opened on the upper and lower templates of the inner mold 3. Then, the piston rod of the hydraulic cylinder 43 is controlled to extend, causing the positioning plate 44 and the friction plate 45 to be inserted into the positioning square groove 31 and the contact groove 32, respectively. Since the size of the positioning square groove 31 is larger than the size of the contact groove 32, the positioning plate 44, when inserted into the positioning square groove 31, will not be able to disengage from the contact groove 32. The square groove 31 can position the friction plate 45, preventing it from extending directly out of the contact groove 32 and impacting the precast box girder when inserted into it. When the friction plate 45, with contact balls 46 on its outer side, is inserted into the contact groove 32 and multiple contact balls 46 contact the inner wall of the precast box girder, and the construction workers pull the inner mold 3 out of the precast box girder using the winch's wire rope, the contact balls 46 rolling on the outer friction plates 45 of the upper and lower templates of the inner mold 3 will roll and rub against the inner wall of the precast box girder during the pull-out process. This reduces the friction generated when the inner mold 3 is pulled out of the precast box girder, thereby reducing the power output of the winch during the pull-out process.

[0023] In one embodiment of the present invention, the friction plate 45 with the rotating groove 451 has a lubricating oil cavity 452 inside, and the lubricating oil cavity 452 is filled with lubricating oil. The lubricating oil cavity 452 is connected to multiple rotating grooves 451. During operation, since the lubricating oil cavity 452 inside the friction plate 45 is filled with lubricating oil and the lubricating oil cavity 452 is connected to the rotating groove 451, when the contact ball 46 rotates and rubs inside the precast box girder, the lubricating oil can lubricate the contact ball 46 and prevent the contact ball 46 from getting stuck in the rotating groove 451 due to concrete impurities or particles adhering to the surface of the contact ball 46, thereby affecting the efficiency and stability of pulling the inner mold 3 out of the precast box girder.

[0024] In one embodiment of the present invention, the inner diameter of the rotating groove 451 is larger than the outer diameter of the contact ball 46, and one-third of the outer spherical surface of the contact ball 46 extends out of the rotating groove 451. The contact ball 46 is elastically slidably disposed in the rotating groove 451 by a rotating contact spring 5, and the other end of the spring 5 is connected to the lubricating oil cavity 452. During operation, when the friction plate 45 on which the contact ball 46 is rotatably disposed extends into the contact through groove 32, the contact ball 46 will contact the inner wall of the precast box girder. At the same time, the inner wall of the precast box girder will exert a squeezing force on the contact ball 46. At this time, the outer ring surface of the contact ball 46 contracts into the lubricating oil cavity 452, and a gap is formed between the contact ball 46 and the rotating groove 451, thereby facilitating the lubricating oil in the lubricating oil cavity 452 to flow into the lubricating oil cavity. The contact ball 46 enters the contact surface between the inner mold 3 and the precast box girder through the gap between the rotating groove 451 and the contact ball 46, thereby further reducing the friction between the inner mold 3 and the precast box girder. This facilitates the quick pulling of the inner mold 3 out of the precast box girder by the wire rope of the winch without causing any safety hazards. When the friction plate 45 with the contact ball 46 is disengaged from the contact groove 32 by the piston rod of the hydraulic cylinder 43, the contact ball 46 on the outer side of the friction plate 45 will extend towards the outer groove of the rotating groove 451 under the push of the spring 5. This allows the contact ball 46 to seal the rotating groove 451, thus preventing the lubricating oil in the lubricating oil cavity 452 from leaking and being wasted when the contact ball 46 is not in contact with the inner wall of the precast box girder.

[0025] In one embodiment of the present invention, an elastic sealing frame 6 is fixedly sleeved around the outer ring of a friction plate 45 with a smooth outer surface, and the elastic sealing frame 6 is elastically pressed and inserted into the contact groove 32. During operation, when the friction plate 45 with a smooth outer surface is inserted into the contact groove 32, the friction plate 45 will drive the elastic sealing frame 6 to be elastically pressed and inserted into the contact groove 32 at the same time, so that the elastic sealing frame 6 can elastically seal the gap between the friction plate 45 and the contact groove 32, thereby preventing mud and sand in the concrete from entering the core cavity of the inner mold 3 through the gap between the friction plate 45 and the contact groove 32 when the construction personnel are pouring concrete.

[0026] In one embodiment of the present invention, the surface of the friction plate 45, which has a smooth outer surface, is coated with a release agent.

[0027] Working principle: When the inner mold 3 needs to be pulled into the reinforcing cage, the drive motor is activated, causing the drive shaft 41 and the symmetrical hydraulic cylinder 43 to rotate. At this time, the two symmetrical friction plates 45 with smooth outer surfaces are rotated to the symmetrical positioning slots 31 and contact grooves 32. Then, the piston rod of the hydraulic cylinder 43 extends, causing the positioning plate 44 and the friction plates 45 with smooth outer surfaces to insert into the positioning slots 31 and contact grooves 32. At this point, the outer surface of the friction plate 45 is flush with the outer surfaces of the upper and lower templates of the inner mold 3, thus enabling the friction plate 45 to contact the upper and lower templates of the inner mold 3 in a manner that... The sealing function is achieved by retracting the two friction plates 45, which have contact balls 46 on their outer surfaces, into the core cavity of the inner mold 3. After the friction plates 45, with their smooth outer surfaces, are sealed onto the upper and lower templates of the inner mold 3, the construction workers use a winch's wire rope to pull the inner mold 3 into the wire cage. Then, the construction workers pour concrete onto the fixed side molds 2 and inner mold 3, allowing it to solidify and form a precast box girder. When it is necessary to pull the inner mold 3 out of the solidified precast box girder, the construction workers control the piston rod of the hydraulic cylinder 43, which is inserted into the contact groove 32 and located below the friction plates 45, to retract. The retraction of this piston rod will drive the positioning plate 44. The friction plate 45 disengages from the positioning square groove 31 and the contact through groove 32, respectively. Then, the drive shaft 41 is rotated, causing the friction plate 45, whose outer surface is equipped with contact balls 46, to rotate to the positioning square groove 31 opened on the upper and lower templates of the inner mold 3. Then, the piston rod of the hydraulic cylinder 43 is extended, causing the positioning plate 44 and the friction plate 45 to be inserted into the positioning square groove 31 and the contact through groove 32, respectively. Since the size of the positioning square groove 31 is larger than the size of the contact through groove 32, the positioning plate 44 can position the friction plate 45 when inserted into the positioning square groove 31, preventing the friction plate 45 from being inserted into the contact through groove 32. When the friction plate 45 extends directly out of the contact groove 32 and impacts the precast box girder, and when the friction plate 45 with contact balls 46 on the outer side is inserted into the contact groove 32, and multiple contact balls 46 contact the inner wall of the precast box girder, when the construction workers pull the inner mold 3 out of the precast box girder through the wire rope of the winch, the contact balls 46 rolling on the friction plate 45 on the outer side of the upper and lower templates of the inner mold 3 will roll and rub against the inner wall of the precast box girder when the inner mold 3 is pulled out, thereby reducing the friction force generated when the inner mold 3 is pulled out of the precast box girder, thereby reducing the power output of the winch when pulling out the inner mold 3.

[0028] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hydraulic formwork device for precast box girders, comprising a base (1), side molds (2), a hydraulic lifting system, and a propulsion system, characterized in that, An inner mold (3) is provided at the center of the side molds (2) located above the base (1) and on both sides. An auxiliary release mechanism (4) is provided in the core cavity of the inner mold (3). The auxiliary release mechanism (4) is used to help pull the inner mold (3) pulled by the traction rope out horizontally from the cast box girder. The auxiliary release mechanism (4) includes a drive shaft (41), a support frame (42), a hydraulic cylinder (43), a positioning plate (44), a friction plate (45), and a contact ball (46). The drive shaft (41) is rotatably supported in the core cavity of the inner mold (3) by multiple support frames (42), and one end of the drive shaft (41) is connected to the output shaft of a drive motor fixed on the support frame (42). The outer ring surface of the drive shaft (41) has at least four hydraulic cylinders (43) arranged in a circumferential array, and each set of hydraulic cylinders (43) in the circumferential array is arranged along the length direction of the drive shaft (41). Multiple positioning square grooves (31) are opened on the upper and lower templates of the inner mold (3), and a contact through groove (32) is opened on the outer side of each positioning square groove (31). The size of the contact groove (32) is smaller than that of the positioning square groove (31). The piston rod end faces of the multiple hydraulic cylinders (43) are fixed with positioning plates (44), and the positioning plates (44) are slidably inserted and aligned with the positioning square groove (31). Each positioning plate (44) has a friction plate (45) on its outer side, and the friction plate (45) is inserted and aligned with the contact groove (32). The outer sides of two symmetrical friction plates (45) are smooth surfaces. The outer sides of the other two symmetrical friction plates (45) are provided with multiple rotating grooves (451), and each rotating groove (451) is rotatably provided with a contact ball (46). The outer sides of the multiple contact balls (46) are flush with the upper and lower outer sides of the inner mold (3).

2. The hydraulic formwork device for precast box girders according to claim 1, characterized in that: The friction plate (45) with the rotating groove (451) has a lubricating oil cavity (452) inside, and the lubricating oil cavity (452) is filled with lubricating oil. The lubricating oil cavity (452) is connected to multiple rotating grooves (451).

3. The hydraulic formwork device for precast box girders according to claim 2, characterized in that: The inner diameter of the rotating groove (451) is larger than the outer diameter of the contact ball (46), and one-third of the outer spherical surface of the contact ball (46) extends out of the rotating groove (451). The contact ball (46) is elastically slidably disposed in the rotating groove (451) by a rotating contact spring (5), and the other end of the spring (5) is connected to the lubricating oil cavity (452).

4. The hydraulic formwork device for precast box girders according to claim 1, characterized in that: The friction plate (45) with a smooth outer surface has an elastic sealing frame (6) fixedly fitted around its outer ring surface, and the elastic sealing frame (6) is elastically squeezed into the contact groove (32).

5. A hydraulic formwork device for precast box girders according to claim 4, characterized in that: The friction plate (45), whose outer surface is smooth, is coated with a release agent.

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