201 results about "Plate girder" patented technology

The utility model relates to an adjustable steering block device for reinforcing external prestressed tendons of a bridge. The adjustable steering block device comprises a hollow slab beam and a steering block device body arranged on the lower side of the hollow slab beam. The steering block device comprises a bottom plate and a screw supporting plate located below the bottom plate, at least one set of adjusting screws are arranged between the bottom plate and the screw supporting plate, each set comprises two vertically-arranged adjusting screws, a steering block is arranged between the two adjusting screws in the same set, the section of the steering block is semicircular, and the arc-shaped face of the steering block faces downwards. The adjusting screw rod is in threaded connection with an upper adjusting nut and a lower adjusting nut which are used for clamping the end of the steering block in a matched mode. According to the adjustable steering block device for reinforcing the external prestressed tendon of the bridge, the damage degree to the bridge is small, the construction efficiency is high, the steering block is detachably installed, consumables are few, the height of the steering block can be adjusted by matching the adjusting screw rod with the adjusting nut, and the use is convenient. The height of the steering block can be directly adjusted according to the condition of prestress relaxation to improve the prestress degree of the prestressed tendon.

The utility model belongs to the technical field of engineering construction, and particularly relates to a pre-tensioning method prestressed concrete plate beam which comprises a concrete plate beam body formed by concrete pouring and a forming base plate. Plate-shaped formworks are symmetrically installed on the top of the forming base plate and located on the two sides of the concrete plate beam body, lead screw sliding blocks are symmetrically and fixedly connected to the positions, close to the two sides, of the bottoms of the formworks, and linear guide rails corresponding to the lead screw sliding blocks are arranged on the peripheries of the lead screw sliding blocks and located at the bottom of the concrete plate beam body. The lead screw sliding blocks are slidably connected with the linear guide rails, auxiliary sliding blocks are correspondingly and fixedly connected to the positions, close to the lead screw sliding blocks, of the bottom of the mold plate, and auxiliary sliding grooves are correspondingly formed in the positions, located on the top of the forming base plate, of the peripheries of the auxiliary sliding blocks. The pre-tensioning pre-stressed concrete plate beam has the advantages that when the pre-tensioning pre-stressed concrete plate beam is prefabricated, mold splitting can be effectively stabilized, and damage to the surface of the pre-tensioning pre-stressed concrete plate beam is avoided.

The utility model relates to the technical field of bridge reinforcement, and discloses a bridge hollow slab girder reinforcement structure and a bridge, which comprises a plurality of hollow slab girders arranged side by side, a plurality of webs are arranged in each hollow slab girder, the bottom surface of each hollow slab girder is provided with longitudinal reinforcers, the number of the longitudinal reinforcers is equal to that of the webs, and the longitudinal reinforcers are in one-to-one correspondence with the webs. The longitudinal reinforcements are arranged in the longitudinal direction of the bridge and comprise upper-layer sticky steel plates and lower-layer sticky steel plates, and the upper-layer sticky steel plates are located between the hollow slab girders and the lower-layer sticky steel plates; the transverse reinforcements are arranged in the transverse direction of the bridge, and all the longitudinal reinforcements are located between the transverse reinforcements and the hollow slab girders. According to the utility model, the problem that a bridge with high requirement on the strength of a reinforcing structure cannot be stably reinforced by a sticky steel plate reinforcing structure in the prior art is solved.

The invention relates to the technical field of plate girder pouring, in particular to an inflatable core mold and a working method thereof.The inflatable core mold comprises an end mold and a plate girder pedestal, the plate girder pedestal is provided with a core mold body and a steel bar frame, the upper side of the core mold body is provided with a PVC half pipe, the core mold body comprises an outer-layer air bag and an inner-layer air bag, the outer-layer air bag is divided into a plurality of independent air cavities, and the inner-layer air bag is divided into a plurality of outer-layer air cavities; the outer-layer air bag and the inner-layer air bag are connected with air valves; the steel bar frame comprises a top plate steel bar and a bottom plate steel bar, a drag hook bar is arranged on the upper side of the core mold, side molds are arranged on the two sides of the steel bar frame, a top supporting structure is arranged on the upper sides of the side molds, and the top supporting structure comprises a pressing lever, a rope sleeve and a tensioning structure; the PVC half pipe and the inflatable core mold support are combined, the PVC half pipe has certain rigidity, stable top reverse support can be provided for the core mold, buoyancy can be effectively resisted, and the deformation risk is reduced; the PVC half pipe can be taken out from the plate girder, so that the construction cost is reduced, and the quality of concrete in the cavity is convenient to observe.

The invention discloses an underground excavation station primary support arch cover method large arch springing structure and a construction method thereof, and aims at solving the technical problems that arch springing stress is concentrated in an upper-soft lower-hard stratum and traditional support settlement is large, and technical breakthrough is achieved through innovative combination of a dynamic adjustable support system and an intelligent grouting process. In the aspect of the structure, the self-adjusting steel pipe pile comprises inward inclination bottom feet with the inward inclination angle of 1: 6-8, a hinged angle adjusting base, a self-adjusting steel pipe pile with the dynamic adjustment of + / -5 degrees, a 600 * 600 * 25 mm partial pressure steel plate, a 45-degree inclined grouting hole channel, a check valve and a bottom longitudinal beam, a pile-plate-beam three-in-one structure is formed, and an optical fiber sensor is arranged in the steel pipe pile to monitor surrounding rock deformation in real time; according to the construction method, three-stage intelligent grouting, 0.1-0.3 MPa low-pressure filling, 0.5-0.8 MPa high-pressure reinforcing and compensation grouting based on monitoring are adopted, concrete is sprayed in cooperation with the telescopic formwork, and installation of the water stop type feet-lock anchor pipe and the water swelling rubber strip are completed synchronously.

The blast furnace molten iron sampling device comprises a double-layer portal frame, transverse plate beams are fixed to the two sides of the top end of the double-layer portal frame, and gear type three-axis moving modules are installed at the top ends of the two transverse plate beams; the gear type three-axis moving module comprises first sliding plates installed at the top end of the transverse plate beam in a sliding mode, a longitudinal plate beam fixed to the top ends of the two first sliding plates, a second sliding plate installed at the top ends of the longitudinal plate beam in a sliding mode and a concentric-square-shaped vertical frame fixed to one side of the top end of the second sliding plate. According to the invention, a full-coverage sampling mode is adopted, so that the spatial distribution and component change of molten iron in the blast furnace can be more accurately reflected, the problem of sample irrepresentativeness caused by a single sampling point is avoided, and the double-joint overturning sampling unit can move at the top end of the double-layer portal frame through the gear type three-axis moving module; and the sampling unit is allowed to flexibly move in a three-dimensional space and is accurately positioned to different areas of the molten iron trough.

The invention discloses a positioning and anchoring device and method for a foam core mold and a reinforcement cage of a hollow slab girder, the device comprises a connecting part connected with the foam core mold, an anchoring part for anchoring the reinforcement cage, a positioning part positioned on a pedestal and a bolt connecting pair, and quick installation and reutilization are realized through a threaded connection and bolt fixing technology. According to the method, a real-time monitoring system is introduced, a correction instruction is generated in combination with data collection and a closed-loop control algorithm, constructors are assisted in accurately adjusting the position of the reinforcement cage, and dynamic errors in the pouring and vibrating process are effectively restrained. And meanwhile, a data-driven quality management system is constructed, and digital recording and process optimization of the construction process are realized. According to the invention, multiple construction scenes are compatible through modular design, the positioning precision and the construction efficiency are remarkably improved, the material waste is reduced, and a reliable guarantee is provided for the structural safety and durability of the prefabricated hollow slab beam.

The invention provides a dip angle and width double-adjusting high-formwork jacking device and a construction method. The dip angle and width double-adjusting high-formwork jacking device comprises a supporting plate supporting rod; the telescopic clamping device is connected to the top of the supporting plate supporting rod and used for clamping a horizontal steel pipe connected to the lower portion of the formwork to be poured in the jacking device; the angle adjusting device is respectively connected with the supporting plate supporting rod and the telescopic clamping device, so that the optimization of space arrangement and the improvement of space utilization efficiency can be realized when the over-limit beam and plate lower template framed bent is erected; and the angle of the supporting plate can be dynamically adjusted according to complex forms caused by the diversity of building functions such as actual inclined plates, beams and haunches. The device is simple in structural form, does not need to be assembled in a field, can be quickly adjusted and mounted, has higher applicability, and improves the stability of an over-limit beam and plate lower framed bent system; accelerated deformation and loss of the jacking and the vertical rod under the eccentric load effect of the horizontal steel pipe are avoided; and the construction efficiency of inclined plates, beams and haunched parts is improved.

This utility model relates to the technical field of engineering construction, and in particular to a drainage channel structure for expansion joints. It includes: an inter-column drainage channel, disposed between adjacent structural columns, with an inter-column connecting plate; clearance grooves are provided on the sides of adjacent structural columns; the inter-column connecting plate is fixedly connected to a structural beam and embedded in the clearance groove; a first inter-beam drainage channel and a second inter-beam drainage channel are respectively disposed at both ends of the inter-column drainage channel, both disposed between adjacent structural beams; each inter-beam drainage channel has a beam bottom connecting plate, fixedly connected to the bottom of the structural beam; the first inter-beam drainage channel, the inter-column drainage channel, and the second inter-beam drainage channel overlap sequentially to form a slope and are interconnected; an expansion joint waterproofing strip is provided between the beam bottom connecting plate and the bottom of the structural beam. This application has the effect of forming a second line of defense against water seepage in expansion joints, preventing indoor water seepage.

The utility model discloses a prestressed concrete hollow slab girder production carrying device which comprises a base plate, a supporting plate is welded to one side of the upper portion of the outer wall of the base plate, a vertical plate is fixedly installed on one side of the upper portion of the outer wall of the supporting plate, and a lifting mechanism is fixedly connected to one side of the inner wall of the vertical plate. A lifting block matched with the lifting mechanism in size is arranged on one side of the outer wall of the lifting mechanism, and a containing groove is formed in the center of the inner wall of the base plate. According to the carrying device for prestressed concrete hollow slab beam production, the fixed connecting mechanism is arranged, meanwhile, the concrete hollow slab bottom positioning mechanism is arranged in a matched mode, in this way, stable positioning of concrete hollow slabs can be achieved, and meanwhile the concrete hollow slabs can be rapidly unloaded conveniently.

The utility model discloses an intra-cavity concrete cleaning device for shear-resistant reinforcement of hollow slab girders, which relates to the technical field of bridge reinforcement and comprises support cloth and two parallel support arms, the two support arms are respectively arranged on two sides of the support cloth, and two ends of the two support arms are connected with folding arms through 90-degree positioning hinges; the folding arms are in a two-section type, the middle of each folding arm is connected through a 180-degree hinge, the folding arms and the support arms are further connected through fixing springs, transverse rigid connection of the support arms after the support arms are unfolded in a cavity is achieved, and supporting positioning blocks are installed on the support arms and used for guaranteeing that the folding arms on the two sides can be unfolded at the same time, and the phenomenon that the folding arms deflect is avoided. The device is convenient to disassemble and assemble, high in flexibility and low in cost, meanwhile, the labor intensity of workers and the overall time cost of a project are reduced, the working efficiency of cleaning concrete in a cavity is improved, and the construction period is shortened.

The embodiment of the application provides a prefabricated functional panel of magnetic levitation transportation, a plate beam structure and a construction method. The prefabricated functional panel of the magnetic levitation transportation comprises a plate body, which is prefabricated as a concrete component; a truss, which is configured as a reinforcing component, is connected to two plate bodies arranged at intervals, two ends of the truss are embedded in the corresponding plate bodies, and at least two trusses are arranged at intervals along the longitudinal direction of the plate body; and a functional component is arranged on each plate body to provide a magnetic levitation function. By prefabricating the functional component on the plate body and connecting the two plate bodies arranged at intervals by the truss, the prefabricated functional panel can be produced modularly; the prefabrication of the functional component ensures the manufacturing precision and installation quality and reduces the problems of inaccurate positioning and low precision in on-site construction and installation.

The present application relates to a kind of highway bridge engineering construction methods, comprising the following steps: first, pile foundation pouring;Second, excavate foundation pit;Third, dig and set operating area;Fourth, break pile head;Fifth, support first formwork;Sixth, pour cushion;Eighth, support second formwork and third formwork;Ninth, lap pier body embedded reinforcement;Tenth, pour pile cap;Eleventh, backfill foundation pit, twelfth, tie pier body reinforcement, pour pier body, prefabricated plate beam, erect plate beam;The present application is by continuing to dig operating area in the bottom surface of foundation pit, and support first formwork around pile foundation, so that pile cap pouring can form convex section, and nest below the bottom surface of foundation pit, support second formwork and third formwork make pour pier body form insertion part, and nest below the upper surface of pile cap, so that the connection of pile foundation and pile cap, pile cap and pier body can better withstand lateral load, enhance the overall structural strength.

The present invention discloses a hollow slab beam with embedded bolt connectors and a construction method thereof, belonging to the technical field of hollow slab beam construction. The top and bottom ends of the side end faces between the hollow slabs are respectively fixedly connected by a plurality of bolts that are matched in pairs and embedded in the hollow slabs at intervals along the longitudinal direction of the hollow slabs. The bolt connector includes a transverse steel bar and a bolt connection end. The transverse steel bar is transversely embedded in the hollow slab, and the two ends are respectively fixedly connected with a bolt connection end for passing and fixing high-strength bolts. The bolt connection end is arranged in the open grooves at the top and bottom ends of the upper end face of the hollow slab and is flush with the side end face of the hollow slab. The present invention can replace the traditional cast-in-place hinged joint structure, enhance the transverse connection stability of the hollow slab beam, simplify the hollow slab construction process, improve the construction quality of the hollow slab, have good bending and shear resistance, and facilitate the rapid replacement of the slab beam in the later stage.

The utility model relates to a bridge for communicating highways on two sides of a river channel, which comprises a plurality of groups of piers, a plurality of rubber supports and a plurality of connecting pieces, the bridge deck slab is arranged at the tops of the two adjacent sets of bridge piers and supported through rubber supports and comprises a plurality of hollow slab beams which are arranged side by side in the length direction of the bridge, a hinge joint is arranged between every two adjacent hollow slab beams, an anchor bolt structure connected with a bridge pier cover beam is arranged in each hinge joint, and a waterproof buffer structure is arranged at a continuous joint on the bridge deck slab. A telescopic structure is arranged at the expansion joint between the bridge spans; the bridge deck pavement concrete layer is poured on the top of the bridge deck slab, and the hinge joint is filled; the medium-grain asphalt concrete layer is poured on the top of the bridge deck pavement concrete layer; and the fine grain type asphalt concrete layer is poured on the top of the medium grain type asphalt concrete layer. Compared with a traditional bridge, the overall performance and durability are improved, and the using effect is good.

The application discloses a kind of installation methods suitable for beam plate of approach bridge reconstruction, comprising the following steps: S01: new approach bridge block;S02: anchor positioning of crane ship;S03: transport box girder component;S04: build bridge erection platform;S05: assemble bridge erector;S06: install box girder;S07: transport plate girder component;S08: bridge erector transverse to reconstruction section approach bridge;S09: install plate girder;S10: disassemble bridge erector.The installation method suitable for beam plate of approach bridge reconstruction of the application, bridge erection platform provides installation platform and howitzer passageway for bridge erector, greatly realizes that installation operation surface does not cross other field operation, "zero" occupation to other operation surface, guarantee progress synchronous follow-up;And whole operation procedure is closely linked, component transfer frequency is less, resource utilization rate reaches more than 90%, improves work efficiency, finished product quality is protected, reduces installation operation risk, maximum limit saves construction cost.

The present application relates to a kind of hollow slab beam hinge joint concrete breaking and disease treatment method without damaging, including the following steps concrete pre-cleaning, bottom plugging, deep repair and surface repair four steps.The present application construction technology is simple, good universality and environmental applicability, can effectively meet the needs of bridge structure rapid repair operation under a variety of environments, and effectively reduce the material usage and work difficulty in bridge repair operation, and can effectively repair the structural defects in bridge structure, thereby greatly improve the work efficiency and quality of bridge repair operation, while effectively reduce the labor intensity and cost of bridge repair and maintenance operation.

The utility model discloses a lifting tool for a flat-top upright post of a top plate. The lifting tool comprises a lifting lug, a lifting hole, a screw rod, a gasket and a reinforcing component which are used for lifting the flat-top upright post of the top plate, a lifting hole is formed in the lifting lug; the screw rod is fixedly arranged on the lifting lug and connected with the top plate flat-top stand column, and the screw rod is reinforced on the lifting lug through a reinforcing assembly; the gasket is arranged on the screw rod in a sliding and sleeving manner; the lifting lug is a steel plate with the thickness of 20 mm, the length of 400 mm and the height of 300 mm; the distance between the lifting hole and the top end of the lifting lug is 100 milliliters; the screw rod is a part for manufacturing a fixed object with the outer diameter of 56 mm; the hoisting tool for the flat-top upright post of the top plate is simple and reasonable in structure, ingenious in design, convenient to manufacture, small in size, light in weight and convenient to transport, not only improves the hoisting stability of the upright post of the plate beam, reduces the safety risk, but also can be repeatedly used, is suitable for the flat-top upright post of the plate beam, and has a wide application prospect. And other large equipment can be hoisted.

This utility model provides a novel prefabricated slab-beam joint connection structure, including a precast composite slab, an internal reinforcing cage, U-shaped additional reinforcing bars, and a cast-in-place layer. The precast composite slab has a U-shaped groove at its end, with the curved portion of the U-shaped groove located within the slab, and the straight portion extending outwards towards the frame beam. The internal reinforcing cage is arranged within the frame beam. The U-shaped additional reinforcing bars are detachably fitted into the U-shaped groove, with their straight portions extending into the internal reinforcing cage. The cast-in-place layer is poured onto the top of the precast composite slab and the frame beam, covering both the internal reinforcing cage and the U-shaped additional reinforcing bars. This utility model overcomes the shortcomings of exposed reinforcement connections and close-fitting connections.

The application provides a reinforcing device of a pre-bent steel beam and a UHPC grouting hollow slab beam bridge, which is used for reinforcing a hollow slab beam, the hollow slab beam is provided with a hinge joint, and the reinforcing device comprises a pre-bent steel beam and an anchor rod, the hinge joint of the hollow slab beam is provided with an anchoring tension hole, the pre-bent steel beam is provided with a through hole, the through hole of the pre-bent steel beam is matched with the anchoring tension hole, the anchor rod passes through the through hole of the pre-bent steel beam and the anchoring tension hole, and the two ends of the anchor rod are connected with the pre-bent steel beam and the hollow slab beam respectively. The pre-bent steel beam is used for applying prestress to the hollow slab beam, the problem of poor transverse transmission capacity of the hinge joint of the hollow slab beam is solved, the transverse connection capacity of the hollow slab beam is increased, and the longitudinal bending resistance capacity is improved.

The utility model relates to the technical field of beam deflection detection, and aims to solve the problems that a mounting frame needs to be fixed on a bridge body when an existing detector is fixed, time and labor are wasted in disassembly and assembly, and a bridge can be damaged to a certain extent. The utility model provides a low plate girder deflection detection support. The low plate girder deflection detection support comprises a detector, a positioning assembly and a lifting rod. The lifting rod is vertically arranged at the top of the positioning assembly; a leveling assembly is arranged at the end, away from the positioning assembly, of the lifting rod. A mounting platform is arranged at the top of the leveling assembly; the detector is arranged at one end, far away from the leveling assembly, of the mounting platform; the beam deflection detection support provided by the utility model is good in accuracy, convenient to disassemble and assemble and convenient to flexibly transfer, and does not cause damage to a bridge body.

The invention provides a reinforcing structure for additionally arranging an anti-collision guardrail on a hinged plate girder bridge and a rapid construction method of the reinforcing structure, and relates to the technical field of municipal infrastructure, the reinforcing structure comprises a plurality of hollow plate girders, a beam top pressure-bearing steel plate and a beam bottom anchoring steel plate, hinge joints are formed in the adjacent hollow plate girders, and vertical mounting holes are formed in the length directions of the hinge joints; beam top pressure-bearing steel plates are arranged on the upper surfaces of the hollow plate beams, beam bottom anchoring steel plates are arranged on the lower surfaces of the hollow plate beams, high-strength split bolts penetrate through the beam top pressure-bearing steel plates, the vertical mounting holes and the beam bottom anchoring steel plates and are tightened and fixed through fixing assemblies, and anti-collision guardrails are additionally arranged on the beam top pressure-bearing steel plates. According to the method, the procedure of planting steel bars and drilling holes in the plate beam is thoroughly avoided, the risks of damaging the prestressed steel bars and weakening the effective section of the main beam are fundamentally eliminated, the structural integrity and bearing capacity of an original bridge are protected to the maximum extent, the core reinforcing component can be prefabricated in a factory, construction is fast and efficient, and comprehensive benefits are remarkable.

The application discloses a reinforcing connection structure between a prefabricated floor and a concrete beam, and belongs to the field of building structure reinforcement. In view of the problems of poor integrity and weak anti-seismic performance of the connection between the prefabricated floor and the beam in an existing masonry structure, a bidirectional reinforcing mode is adopted, in which a top steel plate covers a beam joint area, and a bottom angle steel covering plate covers the bottom and the side of the beam. Through the synergistic effect of a bonding agent and staggered arranged anchor bolts, a composite reinforced interface is formed, and the shear performance and in-plane stiffness of the connection joint are significantly improved. Meanwhile, the deformation resistance of the angle steel is strengthened by the setting of the spaced distribution of stiffening ribs. The structure guarantees the reliability of the connection between the prefabricated floor and the concrete beam under the premise that the original structure is not removed, restrains the joint damage under the action of the earthquake, has the characteristics of convenient construction and wide adaptability, and is suitable for the seismic reinforcement and reconstruction of stock masonry buildings.

The utility model relates to the technical field of bridges, in particular to a hollow slab girder structure and a bridge structure. According to the hollow slab beam structure, all middle sections are sequentially and continuously arranged between two end sections in the length direction of the end sections, all the middle sections and all the end sections are connected to form a whole, and prestressed steel bundles penetrate through corresponding cavities of all the middle sections and corresponding prestressed steel bundle preformed holes of the two end sections; the two ends of the prestressed steel beam are correspondingly anchored to the two end sections, so that the hollow slab girder structure meets the stress capacity, the upper portion of the middle section is continuous in the transverse direction, hinge joint components do not need to be arranged, and the problem that the hinge joint components are prone to damage in the using process is solved. According to the hollow slab bridge structure, a hinge joint is omitted in the hollow slab bridge structure, the problem that a hinge joint component is prone to damage in the using process is solved, and the bridge is safer.

The present invention belongs to the technical field of the beam joint device for the conventional-conduction high-speed maglev bridge, and particularly relates to a structure of a conventional-conduction high-speed maglev beam-end slab, which comprises a T-shaped slab and two continuous beam bodies; the T-shaped slab comprises a T-shaped slab track slab beam and a T-shaped slab small pier column connected to the bottom surface of the T-shaped slab track slab beam; both ends of the T-shaped slab track slab beam are respectively arranged on the two continuous beam bodies, and the T-shaped slab small pier column is arranged between the two continuous beam bodies; clamping elastic steel plates are fixed on both sides of the T-shaped slab small pier column in the transverse direction of the bridge, beam-end chutes are arranged on the side surfaces of the beam ends of the two continuous beam bodies close to each other, and the clamping elastic steel plates on both sides of the T-shaped slab small pier column are respectively clamped in the beam-end chutes of the two continuous beam bodies. The present invention can ensure the equality, stability and reliability of the joint and the stability of the T-shaped slab, improve the riding comfort of the maglev train, and enhance the safety and stability of high-speed train operation.

The utility model provides a forepoling bar supporting and protecting device, the forepoling bar supporting and protecting device comprises a forepoling bar assembly and a connecting assembly, the forepoling bar assembly comprises a tubular beam body and a hanging ring, the extension direction of the tubular beam body is consistent with the extension direction of a roadway, the hanging ring is connected with the tubular beam body, and the connecting assembly is connected with the forepoling bar assembly. The hanging ring is used for being fixedly connected with an anchor rod, the number of the forepoling bar assemblies is multiple, the multiple tubular beam bodies are arranged at intervals in the width direction of the roadway, at least part of the forepoling bar assemblies are arranged below a plate beam, and the connecting assemblies are used for connecting every two adjacent forepoling bar assemblies. The forepoling bar supporting and protecting device has the advantages of being good in supporting effect and high in safety.

The invention discloses a prefabricated hollow plate beam formwork structure, relates to the field of road engineering formwork equipment, and solves the problems that when an existing prefabricated hollow plate beam formwork structure is used, the outer edges of the two sides are too close to a hollow plate beam in the folding process of an inner mold, the demolding efficiency is affected, and meanwhile abrasion is likely to occur. Comprising a fixed pipe, a telescopic mechanism, a turnover mechanism, a control mechanism, two sets of first turnover plates and two sets of second turnover plates, a guide plate is fixedly connected to the side face of the fixed pipe, the telescopic mechanism comprises a sliding plate and a sliding part, the turnover mechanism comprises a first gear and a turnover part, and the control mechanism comprises a driving shaft. The two sets of first gears are sequentially rotated, so that the first overturning plate is overturned and folded earlier than the second overturning plate, preliminary contraction is achieved, after the first overturning plate and the second overturning plate are folded, the sliding plates on the two sides are linked to synchronously get close to one side of the fixing pipe, and the width of the whole inner mold during storage is reduced.