Integral sliding box girder inner form

Abstract

The application discloses a whole-pulling type box girder inner mold, which comprises a mounting frame, a plurality of mold plates are arranged on the mounting frame in the circumferential direction, the mold plates comprise a plurality of splicing units in the axial direction, the splicing units are spliced through clamping structures, at least one splicing unit is connected with the mounting frame through an ejection piece, and the remaining splicing units are movably connected with the mounting frame through connecting pieces. A single mold plate is formed by splicing a plurality of splicing units through the clamping structures, and the splicing units without the ejection piece are movably connected with the mounting frame through the connecting pieces. Therefore, when the ejection piece ejects the corresponding splicing unit, the splicing unit will drive the remaining splicing units to be ejected together. At this time, the connecting pieces are passively ejected under the driving of the corresponding splicing units, and the splicing units are not easily subjected to rigid ejection force, so that the possibility that the mold plate is slightly twisted after being ejected can be reduced, and the arrangement number of the ejection pieces of the box girder inner mold is also reduced.

Description

Technical Field

[0001] This invention relates to the field of precast box girder manufacturing technology, and in particular, to an integral pull-out box girder inner mold. Background Technology

[0002] Precast box girders are a common structural component in highway bridge construction, widely used in bridges of varying spans. While precast box girders generally share similar structural forms, their dimensions differ due to variations in span length. The function of the internal formwork support is to stabilize and fix the box girder's internal formwork before concrete pouring, ensuring that the structural dimensions of the formed concrete conform to the design, and protecting the concrete from damage by internal or external forces before it reaches its required strength.

[0003] Currently, Chinese patent CN111421656A discloses an integral pull-out hydraulic inner mold for small box girders, including a central beam with several templates movably arranged circumferentially on the central beam. These templates are ejected by corresponding drive devices. However, to ensure the support stability of individual templates, especially when the length of a single template is long, the corresponding drive device needs to arrange multiple ejector components axially to achieve the ejection support of the template. It is understandable that this not only requires multiple ejector components on a single template, but also, when the ejection accuracy of these components is inconsistent, the ejected template is prone to microscopic distortion, which will lead to unevenness of the inner wall of the cast precast box girder. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an integral pull-out box girder inner mold.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] An integral pull-out box girder inner formwork includes an installation frame. Several templates are arranged circumferentially on the installation frame. Several splicing units are included axially. The splicing units are spliced ​​together by a snap-fit ​​structure. At least one splicing unit is connected to the installation frame by a push-out component, and the remaining splicing units are movably connected to the installation frame by connectors.

[0007] The snap-fit ​​structure includes snap-fit ​​blocks and snap-fit ​​slots respectively disposed on adjacent splicing units, and the snap-fit ​​blocks and snap-fit ​​slots are adapted to each other.

[0008] The template is formed by splicing three splicing units, one of which is connected to the ejector.

[0009] The ejector is located in the middle of the mounting bracket.

[0010] The connector includes a sliding cylinder mounted on the mounting frame and a connecting rod slidably connected to the sliding cylinder. The end of the connecting rod is fixedly connected to the corresponding splicing unit, and an elastic element is also connected to the connecting rod. The elastic element is used to pull the connecting rod into the sliding cylinder.

[0011] The ejector on each of the templates is in the same radial position.

[0012] At least one first bevel gear is rotatably mounted on the mounting frame along the axial direction. Several second bevel gears are also rotatably mounted on the mounting frame around the first bevel gear. The several second bevel gears mesh with the first bevel gears, and each of the several second bevel gears corresponds to one of the several templates. The ejector includes a lead screw connected to the second bevel gear. A push rod is connected to the lead screw through a lead screw nut. The splicing unit is fixedly connected to the end of the push rod. The mounting frame is also provided with a drive assembly, which can drive the first bevel gear to rotate.

[0013] The lead screw can be disengaged from the corresponding second bevel gear via a first electromagnetic clutch.

[0014] The plurality of templates include, in sequence along the circumferential direction, an upper left side plate, a lower left side plate, a lower right side plate, an upper right side plate, and a top plate. The bottom of the mounting frame has a base plate. When the plurality of templates are ejected, the base plate engages between the lower left side plate and the lower right side plate.

[0015] At least two splicing units along the axial direction of the precast box girder are connected to the ejector, and the two sides of the first bevel gear are also meshed with a third bevel gear. The third bevel gear is disengaged and driven by a second electromagnetic clutch, and the ejector rod is provided at the end of the ejector rod. The template is provided with a connecting groove corresponding to the roller, and the template is also provided with a sealing plate for closing the connecting groove.

[0016] When the ejector rod is ejected, the roller extends out of the connecting groove and abuts against the inner wall of the precast box girder, thereby driving the bottom plate to detach from the bottom surface of the precast box girder.

[0017] The beneficial effects of this invention are:

[0018] 1. A single formwork panel is formed by splicing several splicing units through a snap-fit ​​structure. Splicing units without ejector pins are movably connected to the mounting frame via connectors. Therefore, when an ejector pin ejects a corresponding splicing unit, that splicing unit will cause the remaining splicing units to be ejected together. At this time, the connectors are passively ejected under the influence of the corresponding splicing unit, and are less likely to exert a rigid ejection force on the splicing unit. This reduces the possibility of microscopic distortion of the formwork after ejection and also reduces the number of ejector pins required for the box girder's inner formwork.

[0019] 2. The ejector assembly consists of a lead screw, a lead screw nut, and an ejector rod. The lead screw is driven to rotate by the transmission of the first and second bevel gears. The rotating lead screw drives the ejector rod to eject the splicing unit. It can be understood that the lead screw, lead screw nut, and ejector rod form a lead screw ejection pair. Since the lead screw has self-locking properties, there is no need to install additional locking components on the inner formwork of the box girder to ensure strong load-bearing capacity of the formwork.

[0020] 3. The ejector unit achieves separable transmission through a first electromagnetic clutch and a corresponding second bevel gear. This allows for the control of ejecting several templates in a predetermined sequence based on the actual configuration of the box girder. Specifically, when a template needs to be ejected first, the first electromagnetic clutch on the corresponding ejector unit is engaged, while the first electromagnetic clutches on the other ejector units are disengaged. The ejector units in the engaged state will then respond with the ejection action.

[0021] 4. When the precast box girder is poured and several formwork panels are in a contracted state, several first electromagnetic clutches can be controlled to be in a disengaged state, while the second electromagnetic clutches are in an engaged state. At this time, the ejector rod will respond with an ejection action, and then the roller at the end of the ejector rod will eject the sealing plate out of the connecting groove. As the ejector rod continues to eject, the roller will abut against the inner wall of the precast box girder, thereby causing the bottom plate to detach from the bottom surface of the precast box girder. At this point, the inner mold changes from sliding friction to rolling friction, and can then be easily and effortlessly pulled out of the precast box girder as a whole. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure when the support is in place, as shown in the example.

[0023] Figure 2 This is a schematic diagram of the structure during the contraction process in the embodiment;

[0024] Figure 3 This is a schematic diagram of the snap-fit ​​structure;

[0025] Figure 4 This is a structural schematic diagram of the ejector component;

[0026] Figure 5 This is a structural schematic diagram of the connector.

[0027] Reference numerals: 1. Mounting bracket; 2. Template; 3. Splicing unit; 4. Snap-fit ​​structure; 5. Ejector; 6. Connector; 7. Snap-fit ​​block; 8. Snap-fit ​​groove; 9. Sliding cylinder; 10. Connecting rod; 11. Elastic element; 12. First bevel gear; 13. Second bevel gear; 14. Lead screw; 15. Push rod; 16. Drive assembly; 17. First electromagnetic clutch; 18. Upper left side plate; 19. Lower left side plate; 20. Lower right side plate; 21. Upper right side plate; 22. Top plate; 23. Bottom plate; 24. Third bevel gear; 25. Second electromagnetic clutch; 26. Roller; 27. Connecting groove; 28. Sealing plate; 29. ​​Ejector. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0029] It is important to understand that in existing technologies, multiple box girder inner molds are often spliced ​​axially to meet the manufacturing requirements of precast box girders of different lengths. However, for a single box girder inner mold, the length of its individual template 2 becomes particularly important. For example, when the individual template 2 is relatively long, fewer box girder inner molds can be spliced ​​to meet the manufacturing requirements for the same length of precast box girder. As the length of the individual template 2 increases, multiple ejector pieces 5 need to be arranged axially in the individual box girder inner mold to achieve stable support for the template 2.

[0030] It is understandable that this not only requires the arrangement of relatively redundant ejector components 5 in the inner mold of a single box girder, but also that when the ejection accuracy of several ejector components 5 is not the same, the mold 2 after ejection is prone to micro-twist under the rigid ejection force of ejector components 5 at different ejection distances, which will lead to unevenness of the inner wall of the cast precast box girder and will also affect the structural performance of the precast box girder.

[0031] In response, this disclosure proposes an integral pull-out box girder inner mold, including a mounting frame 1. Similar to existing technologies, the mounting frame 1 has several templates 2 arranged circumferentially, and each template 2 includes several splicing units 3 along the axial direction. The splicing units 3 are spliced ​​together by a snap-fit ​​structure 4. In addition, at least one splicing unit 3 is connected to the mounting frame 1 by an ejector 5, that is, these splicing units 3 can be defined as active splicing units 3, which will be actively ejected by the ejector 5; the remaining splicing units 3 are movably connected to the mounting frame 1 by connectors 6. The remaining splicing units 3 referred to are the splicing units 3 not connected to the ejector 5, and these splicing units 3 can be defined as passive splicing units 3, which can be passively ejected by the active splicing units 3.

[0032] It is understandable that when the active splicing unit 3 is ejected, the active splicing unit 3 will drive the passive splicing unit 3 to be ejected together through the snap-fit ​​structure 4. At this time, the connecting piece 6 is passively ejected under the drive of the corresponding passive splicing unit 3, and it is not easy to exert a rigid ejection force on the splicing unit 3. This can reduce the possibility of micro-twisting of the template 2 after ejection, and also reduce the number of ejection parts 5 of the box girder inner formwork.

[0033] For example, the aforementioned snap-fit ​​structure 4 may include snap-fit ​​blocks 7 and snap-fit ​​slots 8 respectively disposed on adjacent splicing units 3, and the snap-fit ​​blocks 7 and snap-fit ​​slots 8 have compatible dimensions. Therefore, when the active splicing unit 3 is ejected, the snap-fit ​​blocks 7 on the active splicing unit 3 can push the adjacent passive splicing unit 3 to be ejected together.

[0034] In some embodiments, a single template 2 may be formed by splicing three splicing units 3, for example, only one splicing unit 3 may be connected to a top-mounted component 5. Figure 3 The preferred embodiment is shown in the case where the ejector 5 is located in the middle of the mounting frame 1. In this case, both ends of the active splicing unit 3 are provided with snap-fit ​​blocks 7, and the passive splicing units 3 on both sides are provided with snap-fit ​​grooves 8.

[0035] As an alternative, a single template 2 can also be formed by splicing two splicing units 3, one of which is connected to an ejector 5. In this case, the ejector 5 is preferably configured to be installed as close as possible to the middle of the mounting frame 1 (i.e., the middle of the template 2) to achieve a more stable and reliable force transmission.

[0036] For example, the connector 6 includes a sliding cylinder 9 mounted on the mounting bracket 1 and a connecting rod 10 slidably connected to the sliding cylinder 9, with the passive splicing unit 3 fixedly connected to the end of the connecting rod 10. In addition, an elastic element 11 fixedly connected to the connecting rod 10 is also provided inside the sliding cylinder 9. For example, the elastic element 11 can be a spring, and the connecting rod 10 can be pulled into the sliding cylinder 9 by the elastic force of the spring.

[0037] Therefore, as the template 2 is ejected, the passive splicing unit 3 exerts a tensile force on the spring; when the active splicing unit 3 retracts, the spring gradually returns to its natural state, causing the passive splicing unit 3 to retract as well.

[0038] In some embodiments, the ejector 5 on each template 2 is configured to be in the same radial position, that is, the arrangement of the splicing unit 3 of each template 2 is also the same, which will make it easier to manufacture and assemble the inner mold of the box girder.

[0039] For example, at least one first bevel gear 12 is rotatably mounted on the mounting frame 1 along the axial direction. The number of first bevel gears 12 corresponds to the number of active splicing units 3. Several second bevel gears 13 are also rotatably mounted on the mounting frame 1 around the first bevel gears 12, and each of the second bevel gears 13 corresponds one-to-one with a number of templates 2. The ejector 5 includes a lead screw 14 that is detachably and driveably connected to the second bevel gears 13 via a first electromagnetic clutch 17. A push rod 15 is connected to the lead screw 14 via a lead screw 14 nut. The active splicing unit 3 is fixedly connected to the end of the push rod 15. It can be understood that the lead screw 14, the lead screw 14 nut, and the push rod 15 form a lead screw 14 ejector assembly. Since the lead screw 14 ejector assembly is prior art, the specific connection relationship and working principle of the lead screw 14, the lead screw 14 nut, and the push rod 15 will not be elaborated in this disclosure. Correspondingly, a drive assembly 16 is also provided on the mounting frame 1, which can drive the first bevel gear 12 to rotate.

[0040] Therefore, when the inner mold needs to be ejected, the first electromagnetic clutch 17 is engaged, and then the drive assembly 16 drives the first bevel gear 12 to rotate. The rotating first bevel gear 12 drives the second bevel gear 13 and the lead screw 14 to rotate. Under the action of the lead screw 14 ejection pair, the ejector rod 15 can drive the template 2 to be ejected.

[0041] It is understandable that, due to the closed structure of the precast box girder, several templates 2 need to be spliced ​​together after being ejected to form a closed structure, thereby meeting the casting requirements of the precast box girder. This makes it difficult for several templates 2 to be ejected and spliced ​​simultaneously, as interference can easily occur due to the simultaneous movement of the templates 2. To solve this problem, in the existing technology, special design is required for the splicing structure of templates 2, which will require additional effort and increase the actual manufacturing cost of the precast box girder; or special design is required for the driving structure of the box girder inner mold, such as using a hydraulic system to achieve different ejection sequences of templates 2, or using different drive sources to achieve different ejection sequences of templates 2. These will greatly increase the system complexity of the box girder inner mold, and it is also not convenient to adjust the ejection sequence of templates 2 in real time. For example, when the configuration of the precast box girder changes, the original ejection sequence of templates 2 may become unsuitable, and the driving structure of the box girder inner mold needs to be readjusted.

[0042] In this disclosure, the ejector 5 achieves separable transmission through a first electromagnetic clutch 17 and a corresponding second bevel gear 13. This allows for the control of ejecting several templates 2 in a predetermined sequence according to the actual configuration of the box girder. Specifically, when a template 2 needs to be ejected first, the first electromagnetic clutch 17 on the corresponding ejector 5 is engaged, while the first electromagnetic clutches 17 on the other ejector 5s are disengaged. The ejector 5s in the engaged state will then respond with an ejection action.

[0043] For example, the aforementioned templates 2 may sequentially include an upper left side plate 18, a lower left side plate 19, a lower right side plate 20, an upper right side plate 21, and a top plate 22 along the circumferential direction, while the bottom of the mounting frame 1 has a bottom plate 23. When the inner formwork of the box girder is ejected, the upper left side plate 18 and the upper right side plate 21 can be controlled to eject first, followed by the top plate 22, the lower left side plate 19, and the lower right side plate 20. At this time, the templates 2 are assembled to form a closed structure.

[0044] Preferably, the splicing unit 3 and the top-out part 5 and the connecting part 6 are all detachably connected, which makes it easy to replace the template 2 for precast box girders with different configurations.

[0045] For example, the drive assembly 16 may include a drive shaft passing through the first bevel gear 12, and a rotary drive component connected to the drive shaft. It can be understood that when multiple box girder inner molds are spliced, the length of the drive shaft can be increased accordingly, so that it passes through several first bevel gears 12, and the rotary drive component can drive several first bevel gears 12 to rotate simultaneously through the drive shaft.

[0046] In some embodiments, at least two active splicing units 3 are provided along the axial direction of the precast box girder. Furthermore, a third bevel gear 24 meshes with both sides of the first bevel gear 12. Similar to the ejector 5, an ejector rod 29 is disengaged from the third bevel gear 24 via a second electromagnetic clutch 25. The ejector rod 29 has the same or similar structure as the ejector 5, and a roller 26 is provided at the end of the ejector rod 29. Correspondingly, a connecting groove 27 opposite to the roller 26 is provided on the template 2, and a sealing plate 28 capable of closing the connecting groove 27 is also spring-loaded on the template 2. For example, a spring connects the sealing plate 28 to the template 2. In its natural state, the spring drives the sealing plate 28 to close the connecting groove 27, thereby ensuring the integrity and sealing of the template 2. Alternatively, a torsion spring can be connected to the sealing plate 28 on a rotating shaft to achieve a spring-loaded connection with the template 2.

[0047] When the precast box girder is poured and several templates 2 are in a retracted state, several first electromagnetic clutches 17 can be controlled to be in a disengaged state, while the second electromagnetic clutches 25 are in an engaged state. At this time, the ejector rod 29 will respond to the ejection action, and then the roller 26 at the end of the ejector rod 29 will push the sealing plate 28 out of the connecting groove 27. As the ejector rod 29 continues to eject, the roller 26 will abut against the inner wall of the precast box girder, thereby causing the bottom plate 23 to detach from the bottom surface of the precast box girder. At this time, the inner mold changes from sliding friction to rolling friction, and can then be easily and effortlessly pulled out of the precast box girder as a whole.

[0048] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. An integral pull-out box girder inner mold, comprising an installation frame (1), wherein a plurality of templates (2) are arranged circumferentially on the installation frame (1), characterized in that: The template (2) includes several splicing units (3) along the axial direction. The splicing units (3) are spliced ​​together by a snap-fit ​​structure (4). At least one splicing unit (3) is connected to the mounting frame (1) by an ejector (5). The remaining splicing units (3) are movably connected to the mounting frame (1) by a connector (6). The connector (6) includes a sliding cylinder (9) disposed on the mounting bracket (1) and a connecting rod (10) slidably connected to the sliding cylinder (9). The end of the connecting rod (10) is fixedly connected to the corresponding splicing unit (3), and an elastic element (11) is also connected to the connecting rod (10). The elastic element (11) is used to pull the connecting rod (10) into the sliding cylinder (9).

2. The integral pull-out box girder inner mold according to claim 1, characterized in that: The snap-fit ​​structure (4) includes snap-fit ​​blocks (7) and snap-fit ​​grooves (8) respectively disposed on adjacent splicing units (3), and the snap-fit ​​blocks (7) and the snap-fit ​​grooves (8) are adapted to each other.

3. The integral pull-out box girder inner mold according to claim 1, characterized in that: The template (2) is formed by splicing three splicing units (3), and the ejector (5) is connected to one of the splicing units (3).

4. The integral pull-out box girder inner mold according to claim 3, characterized in that: The ejector (5) is located in the middle of the mounting bracket (1).

5. The integral pull-out box girder inner mold according to claim 1, characterized in that: The ejector (5) on each of the templates (2) is in the same radial position.

6. The integral pull-out box girder inner mold according to claim 5, characterized in that: At least one first bevel gear (12) is rotatably mounted on the mounting frame (1) along the axial direction. Several second bevel gears (13) are also rotatably mounted on the mounting frame (1) around the first bevel gear (12). The several second bevel gears (13) mesh with the first bevel gear (12). The several second bevel gears (13) correspond one-to-one with several templates (2). The ejector (5) includes a lead screw (14) connected to the second bevel gear (13). A push rod (15) is connected to the lead screw (14) through a lead screw (14) nut. The splicing unit (3) is fixedly connected to the end of the push rod (15). The mounting frame (1) is also provided with a drive assembly (16). The drive assembly (16) can drive the first bevel gear (12) to rotate.

7. The integral pull-out box girder inner mold according to claim 6, characterized in that: The lead screw (14) can be disengaged from the corresponding second bevel gear (13) via the first electromagnetic clutch (17).

8. The integral pull-out box girder inner mold according to claim 6, characterized in that: The templates (2) include, in sequence along the circumference, an upper left side plate (18), a lower left side plate (19), a lower right side plate (20), an upper right side plate (21), and a top plate (22). The mounting frame (1) has a bottom plate (23) at its bottom. When the templates (2) are ejected, the bottom plate (23) is engaged between the lower left side plate (19) and the lower right side plate (20).

9. The integral pull-out box girder inner mold according to claim 6, characterized in that: At least two splicing units (3) along the axial direction of the precast box girder are connected to the ejector (5). The first bevel gear (12) is also meshed with a third bevel gear (24) on both sides. The third bevel gear (24) is disengaged and driven by a second electromagnetic clutch (25). The ejector rod (29) is provided at the end of the ejector rod (29). The template (2) is provided with a connecting groove (27) corresponding to the roller (26). The template (2) is also provided with a sealing plate (28) for closing the connecting groove (27). When the ejector rod (29) is ejected, the roller (26) extends out of the connecting groove (27) and abuts against the inner wall of the precast box girder, thereby driving the inner mold to detach from the bottom surface of the precast box girder.

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