Modular translation construction method of fish-bellied box girder support formwork

Abstract

This invention discloses a modular translation construction method for a fish-belly box girder support formwork, specifically including the following steps: S10, prefabricating a predetermined number of intermediate sections and side sections, and transporting the predetermined number of intermediate sections and side sections to the construction site; S20, modularly assembling the box girder support formwork between the first span piers to form a box girder support formwork, and then laying templates on the box girder support formwork for pouring the first span box girder, while simultaneously installing intermediate sections between the second span piers; S30, after the first span box girder is poured, disassembling the box girder support formwork between the first span piers into intermediate sections and side sections, and translating the side sections to the second span piers to modularly assemble with the intermediate sections to form a box girder support formwork, and then laying templates on the box girder support formwork for pouring the second span box girder, while simultaneously transporting the intermediate sections between the first span piers to the third span piers; S40, performing modular translation assembly of the box girder support formwork for subsequent span box girders according to step S30.

Description

Technical Field

[0001] This invention relates to the field of bridge construction technology, and in particular, to a modular translational construction method for a fish-belly box girder support formwork. Background Technology

[0002] In recent years, with the rapid increase in traffic volume, existing concrete box girder bridges have generally experienced problems such as diagonal cracking of the web and excessive mid-span deflection after a period of operation, and many box girder bridges can no longer meet the requirements. With the updating of continuous bridge design concepts and the continuous optimization of structural cross-sectional dimensions, box girder bridges are gradually developing towards a high-to-width ratio and large cantilever design. The large cantilever fish-belly box girder, also known as a streamlined box girder, features a streamlined side web design, resulting in an aesthetically pleasing appearance and excellent torsional, bending, and wind resistance performance. It perfectly combines urban aesthetics with wind resistance, and is therefore widely used in urban viaducts and interchange ramps. Nowadays, box girders are usually constructed using cast-in-place methods, requiring the erection of box girder formwork on the construction site to support the self-weight of the box girder and operational loads.

[0003] For example, Chinese invention patent application CN110777658A discloses a construction method for an inverted V-shaped cast-in-place arc-shaped wing web formwork system, characterized by the following steps: (i) site leveling and foundation treatment; (ii) bending steel pipes; (iii) erecting full-span cup-lock scaffolding; (iv) bottom formwork installation and support pre-stressing; (v) wing plate formwork installation; (vi) eliminating inelastic deformation; (vii) measuring elastic deformation; and (viii) steel reinforcement installation and inner formwork assembly. This invention uses cup-lock scaffolding and wooden formwork to construct the box girder formwork system, utilizes existing bending machines to bend steel pipes, and replaces heavy steel formwork with bamboo plywood to form the arc-shaped wing plate formwork system, thus better utilizing spatial and temporal advantages to achieve rapid construction.

[0004] However, the aforementioned box girder formwork construction process requires the erection of scaffolding directly on the ground / road surface, which results in low construction efficiency, difficulty in ensuring construction quality and safety, and challenges in adjusting and dismantling the formwork during construction and installation. Summary of the Invention

[0005] This invention provides a modular translational construction method for a fish-belly box girder support formwork to solve the technical problems of low construction efficiency, difficulty in ensuring construction quality and safety of existing box girder support formwork.

[0006] According to one aspect of the present invention, a modular translational construction method for a fish-belly box girder support formwork is provided, specifically including the following steps: S10, prefabricating a predetermined number of intermediate sections and side sections, and transporting the predetermined number of intermediate sections and side sections to the construction site, wherein two side sections are symmetrically connected on both sides of the intermediate section to form a formwork segment, and multiple formwork segments are connected in pairs to form a box girder support formwork, wherein the distance between two side sections in the formwork segment is greater than the width of the pier; S20, using intermediate sections and side sections to modularly assemble the box girder support formwork for the first span of the piers, and then laying templates on the box girder support formwork for the first span of the box girder for casting, while simultaneously installing between the second span piers... Install intermediate sections; S30, after the first span box girder is poured and the strength meets the standard, the box girder support formwork between the first span piers is disassembled into intermediate sections and side sections, and the disassembled side sections are moved to the second span piers to modularly assemble with the intermediate sections to form the box girder support formwork for the second span box girder. Then, templates are laid on the box girder support formwork for the second span box girder for pouring. At the same time, the intermediate sections between the first span piers are transported to the third span piers; S40, according to step S30, the modular translation and assembly of the box girder support formwork for the subsequent span box girders is carried out, that is, the side sections between the previous span piers are moved to the current span piers, and the intermediate sections between the previous span piers are transported to the subsequent span piers.

[0007] As a further improvement to the above technical solution:

[0008] Furthermore, step S20, which involves modularly assembling the box girder support formwork between the first span piers using intermediate sections and side sections, specifically includes the following steps: First, between the first span piers, intermediate sections and side sections are used to assemble a preset number of formwork segments along the length of the bridge. Then, each formwork segment is sequentially connected using connecting components to form the box girder support formwork for the first span box girder through modular assembly.

[0009] Further, step S30 involves disassembling the box girder support formwork between the first span piers into intermediate sections and side sections, and then translating the disassembled side sections to the second span piers to modularly assemble them with the intermediate sections to form the box girder support formwork for the second span box girder. Specifically, this includes the following steps: along the direction from the second span box girder to the first span box girder, the box girder support formwork between the first span piers is disassembled into intermediate sections and side sections in sequence. The side sections in each formwork segment are then translated along the direction from the first span box girder to the second span box girder to the second span piers and connected to the corresponding intermediate sections to form the formwork segment between the second span piers. The formwork segments between the second span piers are then connected sequentially through connecting components, i.e., modularly assembled to form the box girder support formwork for the second span box girder.

[0010] Furthermore, the intermediate section includes a first disc-lock bracket, a first fixed mold frame arranged on the top of the first disc-lock bracket, and a first adjustable top support arranged between the first disc-lock bracket and the first fixed mold frame. The top profile of the first fixed mold frame is the same as that of the box girder.

[0011] Furthermore, the bottom of the first disc buckle bracket is provided with a first adjustable base.

[0012] Furthermore, the bottom of the first disc buckle bracket is provided with a first movable wheel.

[0013] Furthermore, the side wing section includes a second disc fastener bracket, a second fixed mold frame arranged on the top of the second disc fastener bracket, and a second adjustable top support arranged between the second disc fastener bracket and the second fixed mold frame. The top profile of the second fixed mold frame is the same as that of the box girder.

[0014] Furthermore, the bottom of the second disc buckle bracket is provided with a second adjustable base.

[0015] Furthermore, the bottom of the second disc buckle bracket is provided with a second movable wheel.

[0016] Furthermore, a protective railing is provided on the side of the second shaping mold away from the intermediate section.

[0017] The present invention has the following beneficial effects:

[0018] The modular translational construction method of the fish-belly box girder support formwork of the present invention involves prefabricating a predetermined number of intermediate sections and side sections, and transporting these sections to the construction site. During actual construction, the intermediate sections and side sections are assembled into formwork segments, and these formwork segments are then assembled into a box girder support formwork. The intermediate sections and side sections are modularly assembled between the first span piers to form the box girder support formwork for the first span. Templates are then laid on the box girder support formwork for the first span box girder to be poured, while simultaneously, the second span... Intermediate sections are installed between the piers to prepare for the installation of the box girder support formwork for the second span. After the first span of the box girder is poured and reaches the required strength, the box girder support formwork between the first span piers is disassembled into intermediate sections and side sections. The disassembled side sections are then moved to the second span piers to be modularly assembled with the intermediate sections to form the box girder support formwork for the second span. This allows for the cyclical reuse of side sections between different span piers. Furthermore, because the distance between two side sections in the formwork segment is greater than the width of the pier, the translation of the side sections will not be affected by the pier. To overcome obstacles, formwork is laid on the box girder support formwork for the second span of the box girder to facilitate its pouring. Simultaneously, intermediate sections between the piers of the first span are transported to the piers of the third span, allowing for the cyclical reuse of these intermediate sections across different spans. When installing the box girder support formwork for subsequent spans, the side sections between the piers of the previous span are moved to the piers of the current span, and then the intermediate sections between the piers of the previous span are transported to the piers of the subsequent span, thus achieving modular translational assembly of the box girder support formwork. Compared to existing technologies, this solution… The box girder support formwork is formed by modular splicing of intermediate and side sections, which is easy to install and efficient in installation and dismantling. It can also be adapted to bridges of different spans by flexibly controlling the number of spliced ​​sections in the box girder support formwork. The overall stability of the spliced ​​box girder support formwork is higher and the safety during construction is better. At the same time, the side and intermediate sections can also realize the modular combination and translation of the box girder support formwork between different spans, which can significantly improve the efficiency and safety of continuous casting of fish belly box girders. It is highly practical and suitable for widespread promotion and application.

[0019] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0021] Figure 1 This is a flowchart of the modular translation construction method of the fish-belly box girder support formwork according to a preferred embodiment of the present invention.

[0022] Figure 2 This is a construction step diagram of the modular translation construction method of the fish-belly box girder support formwork according to a preferred embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the intermediate section in the modular translation construction method of the fish-belly box girder support formwork according to a preferred embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of the side wing section in the modular translation construction method of the fish-belly box girder support formwork according to a preferred embodiment of the present invention.

[0025] Legend:

[0026] 100. Intermediate section; 110. First disc buckle bracket; 120. First shaping mold frame; 130. First adjustable top support; 140. First adjustable bottom support; 150. First moving wheel; 200. Side wing section; 210. Second disc buckle bracket; 220. Second shaping mold frame; 230. Second adjustable top support; 240. Second adjustable bottom support; 250. Second moving wheel; 260. Guardrail. Detailed Implementation

[0027] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0028] Figure 1 This is a flowchart of the modular translation construction method of the fish-belly box girder support formwork according to a preferred embodiment of the present invention. Figure 2 This is a construction step diagram of the modular translation construction method of the fish-belly box girder support formwork according to a preferred embodiment of the present invention; Figure 3 This is a schematic diagram of the intermediate section in the modular translation construction method of the fish-belly box girder support formwork according to a preferred embodiment of the present invention; Figure 4 This is a schematic diagram of the side wing section in the modular translation construction method of the fish-belly box girder support formwork according to a preferred embodiment of the present invention.

[0029] like Figure 1 and Figure 2As shown, the modular translation construction method of the fish-belly box girder support formwork in this embodiment specifically includes the following steps: S10, prefabricating a predetermined number of intermediate sections 100 and side sections 200, and transporting the predetermined number of intermediate sections 100 and side sections 200 to the construction site. Two side sections 200 are symmetrically connected on both sides of the intermediate section 100 to form a formwork segment. Multiple formwork segments are connected in pairs to form a box girder support formwork. The distance between two side sections 200 in a formwork segment is greater than the width of the pier. S20, using intermediate sections 100 and side sections 200, modularly assembling them between the piers of the first span to form the box girder support formwork for the first span box girder, and then laying templates on the box girder support formwork for the first span box girder to be poured. Simultaneously, the intermediate sections 100 and side sections 200 are installed between the piers of the second span. S30: After the first span of box girder is poured and the strength meets the requirements, the box girder support formwork between the piers of the first span is disassembled into intermediate section 100 and side section 200. The disassembled side section 200 is then moved to the piers of the second span to be modularly assembled with intermediate section 100 to form the box girder support formwork for the second span of box girder. Then, templates are laid on the box girder support formwork for the second span of box girder for pouring. At the same time, intermediate section 100 between the piers of the first span is transported to the piers of the third span. S40: According to step S30, the modular translation and assembly of the box girder support formwork for the subsequent span of box girder is carried out. That is, the side section 200 between the piers of the previous span is moved to the piers of the current span, and then the intermediate section 100 between the piers of the previous span is transported to the piers of the next span.Specifically, the modular translational construction method of the fish-belly box girder support formwork of the present invention involves prefabricating a predetermined number of intermediate sections 100 and side sections 200, and transporting these sections to the construction site. During actual construction, the intermediate sections 100 and side sections 200 are assembled into formwork segments, and these segments are then assembled into a box girder support formwork. The intermediate sections 100 and side sections 200 are modularly assembled between the first span piers to form the box girder support formwork for the first span box girder. Templates are then laid on the box girder support formwork for the first span box girder. During the pouring of the first span box girder, an intermediate section 100 is installed between the second span piers to prepare for the installation of the box girder support formwork for the second span. After the first span box girder is poured and reaches the required strength, the box girder support formwork between the first span piers is disassembled into an intermediate section 100 and side sections 200. The disassembled side sections 200 are then moved to the second span piers to be modularly assembled with the intermediate section 100 to form the box girder support formwork for the second span box girder. This allows for the cyclical reuse of the side sections 200 between different span piers. Furthermore, because the distance between two side sections 200 in the formwork segment is greater than the width of the pier, the side sections... The translation of the wing section 200 is not obstructed by the piers. Formwork is laid on the box girder support formwork of the second span for casting the second span box girder. Simultaneously, the intermediate section 100 between the piers of the first span is transported to the piers of the third span, allowing for the cyclical reuse of the intermediate section 100 between different span piers. When installing the box girder support formwork for subsequent spans, the wing sections 200 between the piers of the previous span are translated to the piers of the current span, and then the intermediate sections 100 between the piers of the previous span are transported to the piers of the subsequent span, thus achieving modular translational assembly of the box girder support formwork. This scheme is... For existing technology, the box girder support formwork is modularly spliced ​​from the intermediate section 100 and the side wing sections 200. This method is easy to install, highly efficient in installation and dismantling, and allows for flexible control of the number of spliced ​​sections to suit bridges of different spans. The spliced ​​box girder support formwork exhibits higher overall stability and better safety during construction. Furthermore, the side wing sections 200 and the intermediate section 100 enable modular combination and translation of the box girder support formwork between different spans, significantly improving the efficiency and safety of continuous casting of fish-belly box girders. This method is highly practical and suitable for widespread promotion and application. It should be understood that the preset quantity can be adaptively selected according to specific circumstances. Optionally, transporting the intermediate section 100 between the first span piers to the third span piers includes the following steps: first, moving the intermediate section 100 between the first span piers along the width direction of the first span box girder to outside the first span piers, and then using hoisting equipment to transport it to the third span piers.

[0030] like Figure 2As shown, in this embodiment, step S20, which involves modularly assembling the box girder support formwork between the first span piers using intermediate sections 100 and side sections 200, specifically includes the following steps: First, between the first span piers, intermediate sections 100 and side sections 200 are used to assemble a predetermined number of formwork segments along the length of the bridge. Then, each formwork segment is sequentially connected using connecting components to modularly assemble the box girder support formwork for the first span box girder. Specifically, the intermediate sections 100 and side sections 200 are spliced ​​to form formwork segments, and then multiple formwork segments are spliced ​​to form the box girder support formwork for the first span box girder, which greatly reduces the difficulty of installing the box girder support formwork and improves the efficiency of installation and disassembly. Optionally, the connecting components include connecting fasteners on the axial ends of the connecting pipes, with connecting fasteners at both axial ends of the connecting pipes for detachable connection to the intermediate sections 100 or side sections 200.

[0031] like Figure 2 As shown in this embodiment, step S30, which involves disassembling the box girder support formwork between the first span piers into intermediate sections 100 and side sections 200, and then translating the disassembled side sections 200 to the second span piers to modularly assemble them with the intermediate sections 100 to form the box girder support formwork for the second span box girder, specifically includes the following steps: along the direction from the second span box girder to the first span box girder, the box girder support formwork between the first span piers is disassembled into intermediate sections 100 and side sections 200 in sequence. The side sections 200 in each formwork segment are then translated along the direction from the first span box girder to the second span box girder to the second span piers and connected to the corresponding intermediate sections 100 to form the formwork segment between the second span piers. The formwork segments between the second span piers are then connected sequentially through connecting components, i.e., modularly assembled to form the box girder support formwork for the second span box girder. Specifically, along the direction from the second span box girder to the first span box girder, the box girder support formwork between the first span piers is disassembled in sections into intermediate sections 100 and side sections 200. That is, the side sections 200 between the first span piers that are close to the second span box girder can be disassembled and moved to the second span piers first, so as to greatly improve the disassembly and movement efficiency of the side sections 200.

[0032] like Figure 3As shown, in this embodiment, the intermediate section 100 includes a first disc-lock bracket 110, a first shaping mold 120 disposed on the top of the first disc-lock bracket 110, and a first adjustable top support 130 disposed between the first disc-lock bracket 110 and the first shaping mold 120. The top profile of the first shaping mold 120 is the same as that of the box girder. Specifically, the first disc-lock bracket 110 vertically supports the first shaping mold 120, and the first shaping mold 120 supports the template. The top profile of the first shaping mold 120 is the same as that of the box girder, so that the middle part of the box girder can be cast and formed. The vertical height of the first shaping mold 120 is adjusted by the first adjustable top support 130 so that the vertical height of the middle part of the box girder meets the design requirements.

[0033] like Figure 3 As shown, in this embodiment, the bottom of the first disc buckle bracket 110 is provided with a first adjustable base 140. Specifically, the vertical height of the first disc buckle bracket 110 is adjusted by adjusting the first adjustable base 140, thereby adjusting the vertical height of the intermediate section 100.

[0034] like Figure 3 As shown, in this embodiment, the bottom of the first disc-lock bracket 110 is provided with a first movable wheel 150. Specifically, the first movable wheel 150 enables the first disc-lock bracket 110 to slide on the foundation surface, thereby allowing the intermediate section 100 to slide on the foundation surface, which greatly improves the transportation efficiency of the intermediate section 100.

[0035] like Figure 4 As shown, in this embodiment, the side wing section 200 includes a second disc-lock bracket 210, a second shaping mold 220 disposed on the top of the second disc-lock bracket 210, and a second adjustable top support 230 disposed between the second disc-lock bracket 210 and the second shaping mold 220. The top profile of the second shaping mold 220 is the same as that of the box girder. Specifically, the second disc-lock bracket 210 vertically supports the second shaping mold 220, and the second shaping mold 220 supports the template. The top profile of the second shaping mold 220 is the same as that of the box girder, so that the side of the box girder can be cast and formed. The vertical height of the second shaping mold 220 is adjusted by the second adjustable top support 230 so that the vertical height of the side of the box girder meets the design requirements.

[0036] like Figure 4 As shown, in this embodiment, the bottom of the second disc buckle bracket 210 is provided with a second adjustable base 240. Specifically, the vertical height of the second disc buckle bracket 210 is adjusted by adjusting the second adjustable base 240, thereby adjusting the vertical height of the side wing section 200.

[0037] like Figure 4As shown, in this embodiment, the bottom of the second disc-lock bracket 210 is provided with a second movable wheel 250. Specifically, the second movable wheel 250 enables the second disc-lock bracket 210 to slide on the foundation surface, thereby allowing the side wing section 200 to slide on the foundation surface, which greatly improves the translation efficiency of the side wing section 200.

[0038] like Figure 4 As shown, in this embodiment, a guardrail 260 is provided on the side of the second formwork 220 away from the intermediate section 100. Specifically, the guardrail 260 improves the safety during the box girder pouring process to prevent workers from accidentally falling from either side when laying formwork or pouring concrete on the box girder support formwork. Optionally, a safety net is laid on the guardrail 260.

[0039] like Figure 4 As shown in this embodiment, the box girder support formwork also includes clamps for connecting the box girder piers, which are connected to the formwork sections. Specifically, after the multiple formwork sections under the piers are assembled, the formwork sections closest to the box girder piers are connected to the piers via clamps to fix the box girder support formwork and improve the stability and safety during the casting of the box girder.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A modular translational construction method for a fish-belly box girder support formwork, characterized in that, Specifically, the following steps are included: S10, prefabricate a predetermined number of intermediate sections (100) and side sections (200), and transport the predetermined number of intermediate sections (100) and side sections (200) to the construction site. Two side sections (200) are symmetrically connected on both sides of the intermediate section (100) to form a formwork segment. Multiple formwork segments are connected in pairs to form a box girder support formwork. The distance between two side sections (200) in the formwork segment is greater than the width of the pier. S20, the intermediate section (100) and the side section (200) are modularly assembled between the first span piers to form the box girder support formwork of the first span box girder, and then the formwork is laid on the box girder support formwork of the first span box girder for the pouring of the first span box girder, while the intermediate section (100) is installed between the second span piers. S30, after the first span of box girder is poured and the strength meets the standard, the box girder support formwork between the first span piers is disassembled into an intermediate section (100) and a side section (200), and the disassembled side section (200) is moved to the second span pier to be modularly assembled with the intermediate section (100) to form the box girder support formwork for the second span box girder. Then, the formwork is laid on the box girder support formwork for the second span box girder to be poured. At the same time, the intermediate section (100) between the first span piers is transported to the third span pier. S40, according to step S30, the modular translation and assembly of the box girder support formwork for the subsequent span box girder is carried out, that is, the side wing section (200) between the piers of the previous span is translated to the piers of the current span, and then the middle section (100) between the piers of the previous span is transported to the piers of the next span. The transportation of the intermediate section (100) between the first span piers to the third span piers includes the following steps: First, the intermediate section (100) between the first span piers is moved to the outside of the first span pier along the width direction of the first span box girder, and then hoisted to the third span pier by hoisting equipment.

2. The modular translational construction method for the fish-belly box girder support formwork according to claim 1, characterized in that, Step S20, which involves modularly assembling the box girder support formwork between the first span piers using intermediate sections (100) and side sections (200), specifically includes the following steps: First, the intermediate section (100) and the side section (200) are used to assemble the pre-set number of formwork segments along the length of the bridge between the first span piers. Then, the formwork segments are connected in sequence through connecting components to form the box girder support formwork for the first span box girder through modular assembly.

3. The modular translational construction method for the fish-belly box girder support formwork according to claim 2, characterized in that, Step S30 involves disassembling the box girder support formwork between the first span piers into an intermediate section (100) and a side section (200), and then moving the disassembled side section (200) to the second span piers to modularly assemble it with the intermediate section (100) to form the box girder support formwork for the second span box girder. The specific steps include: Along the direction from the second span box girder to the first span box girder, the box girder support formwork between the first span piers is disassembled into intermediate sections (100) and side sections (200) in sequence. The side sections (200) in each formwork section are then moved along the direction from the first span box girder to the second span box girder to the second span piers and connected to the corresponding intermediate sections (100) to form the formwork section between the second span piers. The formwork sections between the second span piers are then connected in sequence through connecting components, i.e., modular assembly is used to form the box girder support formwork for the second span box girder.

4. The modular translational construction method for the fish-belly box girder support formwork according to any one of claims 1-3, characterized in that, The intermediate section (100) includes a first disc buckle bracket (110), a first fixed mold frame (120) arranged on the top of the first disc buckle bracket (110), and a first adjustable top support (130) arranged between the first disc buckle bracket (110) and the first fixed mold frame (120). The top profile of the first fixed mold frame (120) is the same as that of the box girder.

5. The modular translational construction method for the fish-belly box girder support formwork according to claim 4, characterized in that, The bottom of the first disc buckle bracket (110) is provided with a first adjustable base (140).

6. The modular translational construction method for the fish-belly box girder support formwork according to claim 4, characterized in that, The bottom of the first disc buckle bracket (110) is provided with a first movable wheel (150).

7. The modular translational construction method for the fish-belly box girder support formwork according to any one of claims 1-3, characterized in that, The side wing section (200) includes a second disc buckle bracket (210), a second fixed mold frame (220) arranged on the top of the second disc buckle bracket (210), and a second adjustable top support (230) arranged between the second disc buckle bracket (210) and the second fixed mold frame (220). The top profile of the second fixed mold frame (220) is the same as that of the box girder.

8. The modular translational construction method for the fish-belly box girder support formwork according to claim 7, characterized in that, The bottom of the second disc buckle bracket (210) is provided with a second adjustable base (240).

9. The modular translational construction method for the fish-belly box girder support formwork according to claim 7, characterized in that, The bottom of the second disc buckle bracket (210) is provided with a second movable wheel (250).

10. The modular translational construction method for the fish-belly box girder support formwork according to claim 7, characterized in that, The second shaping mold (220) has a guardrail (260) on the side away from the intermediate section (100).

Images