An integrated carbon fiber bicycle saddle molding die
By designing a compression molding die with a fixed mold base, a moving mold assembly, an opening and closing electric push rod, and an ejection device, the problem of uneven force on the saddle in traditional demolding methods was solved, achieving high-quality demolding and efficient production, reducing the defect rate, and improving production efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TAISHI TECHNOLOGY (SHENZHEN) CO LTD
- Filing Date
- 2025-04-30
- Publication Date
- 2026-05-26
AI Technical Summary
Traditional demolding methods make it difficult to ensure that the stress is evenly distributed in all parts of the one-piece carbon fiber bicycle saddle, resulting in deformation, cracking, high defect rate, and difficulty in demolding.
A compression molding die was designed, comprising a fixed mold base, a moving mold assembly, an opening and closing electric push rod, an ejection device, and a demolding auxiliary component. Through the coordinated work of the guide rod and the ejection device, the precise closing and separation of the saddle mold is ensured. By utilizing the demolding auxiliary component and the ejection device, uniform force application and stable ejection are achieved.
It improved demolding quality, reduced the defect rate, increased demolding efficiency, met market demand, reduced production costs, and promoted the large-scale production and application of integrated carbon fiber bicycle saddles.
Smart Images
Figure CN224276299U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of bicycle saddle molding technology, specifically an integrated carbon fiber bicycle saddle molding die. Background Technology
[0002] In the bicycle manufacturing industry, as people's requirements for riding experience continue to improve, one-piece carbon fiber bicycle saddles have attracted much attention due to their excellent performance advantages. Carbon fiber material has the characteristics of high strength and low density. Saddles made of it can not only effectively reduce the overall weight of the bicycle and improve riding speed and flexibility, but also have good comfort and durability. However, the production of one-piece carbon fiber bicycle saddles currently faces many challenges.
[0003] Traditional demolding methods cannot guarantee that the saddle is evenly stressed during demolding, which can easily lead to saddle deformation and cracking, affecting the product's appearance and structural strength, resulting in a high defect rate. The inherent properties of carbon fiber materials result in greater friction between the carbon fiber material and the mold, increasing the difficulty of demolding. To address this, we have proposed an integrated carbon fiber bicycle saddle compression molding die. Utility Model Content
[0004] (a) Technical problems to be solved
[0005] To address the shortcomings of existing technologies, this utility model provides an integrated carbon fiber bicycle saddle molding die, which solves the aforementioned problems.
[0006] (II) Technical Solution
[0007] To achieve the above-mentioned objectives, this utility model provides the following technical solution: an integrated carbon fiber bicycle saddle molding die, comprising a fixed mold frame, a moving module, an opening and closing electric push rod, and an ejection device. The fixed mold frame has a top support plate at its top, and the opening and closing electric push rod is located at the center of the top of the top support plate. The opening and closing electric push rod is fixedly connected to the top support plate by an adapter screw. The fixed mold frame has a bottom support plate at its bottom, and the bottom of the bottom support plate has an ejection device. The bottom of the ejection device is fixedly connected to the bottom support plate by an adapter bolt, and the top output push rod shaft of the ejection device is inserted into the interior of the fixed mold frame. The moving module is located at the top of the interior of the fixed mold frame. The four corners of the moving module are slidably connected to the interior of the fixed mold frame, and the top center of the moving module is welded to the bottom output push rod shaft of the opening and closing electric push rod.
[0008] Preferably, the fixed mold frame has a saddle mold corresponding to the bottom end of the moving module, and the fixed mold frame has four demolding auxiliary parts distributed symmetrically on the axis, which are in contact with the bottom of the output shaft end component of the ejection device.
[0009] Preferably, the fixed mold frame is provided with guide rods at the bottom of the four corners of the top support plate, and the guide rods are slidably connected to the four corners of the moving mold. The fixed mold frame is provided with a molding cavity, the top opening of the molding cavity is connected to the saddle mold, and the bottom of the molding cavity is provided with mating grooves at the four corners. The demolding auxiliary parts are placed in the mating grooves, the side wall of the mating groove is provided with a mating sliding hole, and the bottom center of the molding cavity is provided with a cylindrical hole.
[0010] Preferably, the demolding aid consists of three parts: a first mating plate, a second mating plate, and five equidistant elastic elements. The first mating plate has a mating rod at the top center, which is slidably connected to the mating sliding hole. The bottom of the first mating plate has five equidistant auxiliary rods. The top of the second mating plate has an auxiliary cylinder that is slidably connected to the auxiliary rods. The outer side of the auxiliary cylinder has elastic elements, and the two ends of the elastic elements are welded to the opposite ends of the first and second mating plates, respectively.
[0011] Preferably, the top output push rod shaft of the ejector device is connected to the central cylindrical hole at the bottom of the molding cavity, and the top of the ejector device is provided with an ejector plate, which is placed at the bottom of the molding cavity. The four corners of the bottom of the ejector plate are attached to the top of the mating plate. Each of the four corners of the top of the ejector plate is provided with a secondary ejector rod, and the center of the top of the ejector plate is provided with a main ejector rod.
[0012] Preferably, the saddle mold is connected to the top of the molding cavity, and a main demolding hole is provided in the center of the saddle mold, which is slidably connected to the main ejector rod. Auxiliary demolding holes are provided at the four corners of the saddle mold, which are slidably connected to the auxiliary ejector rod.
[0013] (III) Beneficial Effects
[0014] Compared with the prior art, this utility model provides an integrated carbon fiber bicycle saddle molding die, which has the following advantages:
[0015] 1. This integrated carbon fiber bicycle saddle molding die improves demolding quality and reduces the defect rate. Through a rationally designed ejection device and demolding aids, the die effectively solves the problem of uneven force distribution on the saddle in traditional demolding methods. The main ejector rod and auxiliary ejector rod apply force evenly to the bottom of the saddle. Combined with the stable support of the ejector plate provided by the demolding aids, this prevents deformation and cracking of the saddle during demolding. The elastic components and sliding cooperation between the auxiliary rod and auxiliary cylinder in the demolding aids prevent tilting or offset of the ejector plate, ensuring demolding stability, greatly improving product quality, reducing the defect rate, lowering production costs for enterprises, and enhancing product competitiveness.
[0016] 2. This integrated carbon fiber bicycle saddle molding die is adapted to the characteristics of carbon fiber, improving demolding efficiency. Addressing the high friction between carbon fiber and the mold, this die features a specialized demolding structure. Guide rods ensure precise closing and separation of the moving module and the saddle mold, reducing additional friction caused by inaccurate mold fit. The ejection device and demolding aids work together to quickly and smoothly eject the molded saddle from the mold. Compared to traditional demolding methods, this die significantly improves demolding efficiency, shortens the production cycle, meets the large market demand for integrated carbon fiber bicycle saddles, helps companies improve production efficiency, increase economic benefits, and promotes the large-scale production and application of integrated carbon fiber bicycle saddles. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the integrated carbon fiber bicycle saddle molding die structure of this utility model;
[0018] Figure 2 This is a cross-sectional schematic diagram of the integrated carbon fiber bicycle saddle molding die of this utility model;
[0019] Figure 3 This is a quarter-section view of the integrated carbon fiber bicycle saddle molding die of this utility model;
[0020] Figure 4 This is a schematic diagram of the mold frame of this utility model;
[0021] Figure 5 This is a schematic diagram of the ejection device of this utility model;
[0022] Figure 6 This is a cross-sectional view of the demolding aid component of this utility model;
[0023] Figure 7 This is a schematic diagram of the saddle mold of this utility model.
[0024] In the diagram: 1. Fixed mold frame; 2. Moving mold assembly; 3. Opening and closing electric push rod; 4. Ejection device; 5. Saddle mold; 6. Demolding auxiliary component; 7. Guide rod; 8. Top support plate; 9. Molding cavity; 10. Mating groove; 11. Mating slide hole; 12. Bottom support plate; 13. Ejection plate; 14. Secondary ejector rod; 15. Main ejector rod; 16. Mating plate one; 17. Elastic component; 18. Mating plate two; 19. Mating rod; 20. Auxiliary rod; 21. Auxiliary cylinder; 22. Main demolding hole; 23. Secondary demolding hole. Detailed Implementation
[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0026] Please see Figure 1-7 An integrated carbon fiber bicycle saddle molding die includes a fixed mold frame 1, a moving module 2, an opening and closing electric push rod 3, and an ejection device 4. The fixed mold frame 1 has a top support plate 8 on top, and the opening and closing electric push rod 3 is located at the top center of the top support plate 8. The opening and closing electric push rod 3 is fixedly connected to the top support plate 8 by an adapter screw. The fixed mold frame 1 has a bottom support plate 12 at the bottom, and the bottom support plate 12 has an ejection device 4 on top. The bottom of the ejection device 4 is fixedly connected to the bottom support plate 12 by an adapter bolt. The top output push rod shaft of the ejection device 4 is inserted into the interior of the fixed mold frame 1. The moving module 2 is located at the top of the interior of the fixed mold frame 1. The four corners of the moving module 2 are slidably connected to the interior of the fixed mold frame 1, and the top center of the moving module 2 is welded to the bottom output push rod shaft of the opening and closing electric push rod 3.
[0027] Furthermore, the fixed mold frame 1 is provided with a saddle mold 5 at the bottom of the moving module 2, and the fixed mold frame 1 is provided with four demolding auxiliary parts 6 distributed symmetrically on the axis. The demolding auxiliary parts 6 are attached to the bottom of the output shaft end of the ejection device 4. The demolding auxiliary parts 6 can effectively assist and support the ejection plates 13 at the four corners of the ejection device 4 during the lifting and ejection operation, ensuring that the ejection plates 13 will not tilt or shift, thus effectively improving the demolding quality.
[0028] Furthermore, the top of the fixed mold frame 1 is provided with guide rods 7 at the bottom of the four corners of the top support plate 8. The guide rods 7 are slidably connected to the four corners of the moving module 2. The fixed mold frame 1 has a molding cavity 9 inside. The top opening of the molding cavity 9 is connected to the saddle mold 5. The bottom of the molding cavity 9 has a mating groove 10 at each of the four corners. The demolding auxiliary part 6 is placed inside the mating groove 10. The side wall of the mating groove 10 has a mating sliding hole 11. The bottom center of the molding cavity 9 has a cylindrical hole. The guide rods 7 ensure the closing accuracy between the moving module 2 and the saddle mold 5 inside the fixed mold frame 1, ensuring the quality and accuracy of the subsequent model.
[0029] Furthermore, the demolding aid 6 consists of three parts: a first mating plate 16, a second mating plate 18, and five equidistant elastic elements 17. The first mating plate 16 has a mating rod 19 at its top center, which is slidably connected to the mating sliding hole 11. The bottom of the first mating plate 16 has five equidistant auxiliary rods 20. The top of the second mating plate 18 has an auxiliary cylinder 21 that is slidably connected to the auxiliary rods 20. The outer side of the auxiliary cylinder 21 is provided with elastic elements 17. The two ends of the elastic elements 17 are welded to the opposite ends of the first mating plate 16 and the second mating plate 18, respectively. The elastic elements 17 of the demolding aid 6 are always in a compressed state. The sliding connection between the auxiliary rods 20 and the auxiliary cylinder 21 ensures the stability of the support of the demolding aid 6 for the ejector plate 13 and prevents deflection and shaking. The mating rods 19 play a guiding role to prevent the demolding aid 6 from shaking as a whole.
[0030] Furthermore, the top output push rod shaft of the ejector device 4 is connected to the central cylindrical hole at the bottom of the molding cavity 9. The top of the ejector device 4 is provided with an ejector plate 13, which is placed at the bottom of the molding cavity 9. The four corners of the bottom of the ejector plate 13 are attached to the top of the mating plate 16. Each of the four corners of the top of the ejector plate 13 is provided with a secondary ejector rod 14, and the center of the top of the ejector plate 13 is provided with a main ejector rod 15. The main ejector rod 15 and the secondary ejector rod 14 effectively ensure that a uniform force is applied to the bottom of the saddle forming inside the saddle mold 5 for ejection, thus ensuring the quality of the demolded product.
[0031] Furthermore, the saddle mold 5 is connected to the top of the molding cavity 9, and the saddle mold 5 has a main demolding hole 22 in the center, which is slidably connected to the main ejector rod 15. The saddle mold 5 has secondary demolding holes 23 at the four corners, which are slidably connected to the secondary ejector rod 14.
[0032] Structural Description:
[0033] Fixed mold frame 1: Fixed mold frame 1 is the basic support structure of the mold. It has a top support plate 8 at the top and a bottom support plate 12 at the bottom. The moving module 2 and saddle mold 5 are installed inside, providing an installation foundation and stable support for the various parts of the mold.
[0034] Moving module 2: Moving module 2 is located inside the top of the fixed mold frame 1. Its four corners are slidably engaged with the fixed mold frame 1, and its top center is connected to the opening and closing electric push rod 3. Under the action of the opening and closing electric push rod 3, it realizes the opening and closing action with the saddle mold 5.
[0035] Opening and closing electric push rod 3: The opening and closing electric push rod 3 is fixed to the top support plate 8 by the adapter screw. Its output push rod shaft is welded to the moving module 2, providing power to make the moving module 2 move up and down to complete the opening and closing operation of the mold.
[0036] Ejection device 4: Ejection device 4 is installed on the bottom support plate 12. The top output push rod shaft passes through the fixed mold frame 1 and ejects the forming saddle from the saddle mold 5 through the ejection plate 13 and the main and auxiliary ejection rods to achieve demolding.
[0037] Saddle mold 5: The saddle mold 5 is installed in the fixed mold frame 1 and fits with the top of the molding cavity 9. The main and auxiliary demolding holes are opened inside. It is a key component for molding carbon fiber material into a saddle and determines the shape of the saddle.
[0038] Demolding aid 6: Demolding aid 6 consists of mating plate 16, mating plate 2 18 and elastic element 17. It is located below ejector plate 13 and provides auxiliary support for ejector plate 13 to ensure smooth demolding and prevent tilting and displacement.
[0039] Guide rod 7: The guide rod 7 is set at the bottom of the four corners of the top support plate 8 on the top of the fixed mold frame 1, and slides with the four corners of the moving module 2 to ensure the closing accuracy of the moving module 2 and the saddle mold 5 and improve the quality of the model;
[0040] Top support plate 8: The top support plate 8 is located on the top of the fixed mold frame 1 and is used to install the opening and closing electric push rod 3. It provides an installation position for the opening and closing electric push rod 3, ensures its stability, and assists in realizing the opening and closing of the mold.
[0041] Molding cavity 9: Molding cavity 9 is located inside the fixed mold frame 1. The top of it mates with the saddle mold 5, and the bottom has a cylindrical hole and a mating groove 10. It is the space for molding carbon fiber materials under high temperature and high pressure.
[0042] Mating groove 10: The mating groove 10 is located at the four corners of the bottom end inside the molding cavity 9. It is used to place the demolding aid 6, provide an installation position for the demolding aid 6, and assist in achieving stable demolding.
[0043] Matching slide hole 11: The matching slide hole 11 is opened on the side wall of the matching groove 10 and slides with the matching rod 19. It plays a guiding role for the demolding auxiliary part 6, preventing it from shaking as a whole and ensuring demolding stability.
[0044] Bottom support plate 12: The bottom support plate 12 is located at the bottom of the fixed mold frame 1 and is used to install the ejector device 4, provide support for the ejector device 4, and ensure that the ejector device 4 works stably.
[0045] Ejector plate 13: Ejector plate 13 is located at the top of ejector device 4 and at the bottom of the molding cavity 9. It ejects the molding saddle through the main and auxiliary ejector rods and is a key actuator of ejector device 4.
[0046] Secondary ejector rod 14: The secondary ejector rod 14 is located at the top four corners of the ejector plate 13 and cooperates with the secondary demolding holes at the four corners of the saddle mold 5. It assists the main ejector rod 15 in applying force evenly to the bottom of the saddle to ensure smooth demolding.
[0047] Main ejector rod 15: The main ejector rod 15 is located at the top center of the ejector plate 13 and cooperates with the main demolding hole at the center of the saddle mold 5. It is mainly responsible for applying force to the bottom of the saddle to achieve demolding of the saddle.
[0048] Mating plate 16: Mating plate 16 is a component of demolding auxiliary part 6. It has a mating rod 19 at the top and an auxiliary rod 20 at the bottom. It works together with mating plate 2 18 and elastic part 17 to support ejector plate 13.
[0049] Elastic element 17: Elastic element 17 connects mating plate 16 and mating plate 2, and is always in a compressed state to provide a buffer for demolding auxiliary part 6, ensuring stable support for ejector plate 13 and preventing shaking;
[0050] Mating plate 2 18: Mating plate 2 18 is part of demolding auxiliary component 6. It has an auxiliary cylinder 21 at the top that slides with the auxiliary rod 20. Together with mating plate 1 16 and elastic component 17, it assists in the stable demolding of ejector plate 13.
[0051] Matching rod 19: The matching rod 19 is installed at the top center of the matching plate 16 and slides with the matching sliding hole 11. It plays a guiding role for the demolding auxiliary part 6 and ensures its stable support for the ejector plate 13.
[0052] Auxiliary rod 20: The auxiliary rod 20 is located at the bottom of mating plate 16 and slides with the auxiliary cylinder 21 at the top of mating plate 28 to enhance the stability of the demolding auxiliary part 6 supporting the ejector plate 13.
[0053] Auxiliary cylinder 21: The auxiliary cylinder 21 is installed on the top of the mating plate 2 18 and slides with the auxiliary rod 20. It works with the elastic element 17 to ensure stable support of the demolding auxiliary element 6 to the ejector plate 13.
[0054] Main demolding hole 22: The main demolding hole 22 is located in the center of the saddle mold 5 and slides with the main ejector rod 15. It is the channel through which the main ejector rod 15 ejects from the saddle and assists in demolding.
[0055] Secondary ejection holes 23: The secondary ejection holes 23 are located at the four corners inside the saddle mold 5 and slide with the secondary ejector rod 14 to assist the main ejector rod 15, so that the saddle is subjected to more even force during demolding.
[0056] Working principle: Install the integrated carbon fiber bicycle saddle molding die correctly according to the diagram. During use, first place the pre-treated carbon fiber material into the saddle mold 5 inside the molding cavity 9. Activate the opening / closing electric push rod 3. The opening / closing electric push rod 3 is fixedly connected to the top support plate 8 via matching screws. Its bottom output push rod shaft is welded to the top center of the moving module 2. Under the action of the opening / closing electric push rod 3, the moving module 2 moves downward along the guide rod 7. The guide rod 7 is located at the top of the fixed mold frame 1, corresponding to the bottom corners of the top support plate 8, and is slidably connected to the four corners of the moving module 2. The closing accuracy of the moving module 2 and the saddle mold 5 inside the fixed mold frame 1 was ensured, guaranteeing the quality and accuracy of subsequent models. The moving module 2 moved downwards to fit tightly with the saddle mold 5. Under high temperature and high pressure, the carbon fiber material gradually solidified and formed into an integral carbon fiber bicycle saddle in the molding cavity 9. After molding, the ejector device 4 was activated. The bottom of the ejector device 4 was fixed to the bottom support plate 12 by adapter bolts. Its top output push rod shaft passed into the interior of the fixed mold frame 1 and was connected to the central cylindrical hole at the bottom of the molding cavity 9. An ejector plate 13 was provided at the top and located in the molding cavity 9. The bottom of the inner part, with its four corners, fits against the top of the first mating plate 16. The demolding auxiliary component 6 consists of the first mating plate 16, the second mating plate 18, and the elastic component 17. The first mating plate 16 is slidably connected to the sliding hole 11 via the mating rod 19, serving as a guide to prevent overall shaking. The bottom auxiliary rod 20 is slidably engaged with the auxiliary cylinder 21 at the top of the second mating plate 18. The two ends of the elastic component 17 are welded to the opposite ends of the first mating plate 16 and the second mating plate 18, respectively, and are always in a compressed state to ensure the stability of the support for the ejector plate 13 and prevent deflection and shaking. The main... Ejector rod 15 and auxiliary ejector rod 14 are slidably connected to the main ejector hole 22 at the center of the saddle mold 5 and the auxiliary ejector holes 23 at the four corners, respectively. As the ejector device 4 works, the main ejector rod 15 and auxiliary ejector rod 14 rise synchronously, applying a uniform force to the bottom of the saddle formed inside the saddle mold 5, and ejecting the saddle smoothly. Throughout the process, the ejection auxiliary component 6 plays an effective auxiliary support role in the ejection work of the four corners of the ejector plate 13, ensuring that the ejector plate 13 will not tilt or shift, thereby achieving high-quality demolding and obtaining a one-piece carbon fiber bicycle saddle that meets the requirements.
[0057] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. An integrated carbon fiber bicycle saddle molding die, comprising a fixed mold frame (1), a moving mold assembly (2), an opening and closing electric push rod (3), and an ejection device (4), characterized in that: The fixed mold frame (1) is provided with a top support plate (8) at the top. The top center of the top support plate (8) is provided with an electric push rod (3). The electric push rod (3) is fixedly connected to the top support plate (8) by an adapter screw. The fixed mold frame (1) is provided with a bottom support plate (12) at the bottom. The bottom support plate (12) is provided with an ejector device (4) at the top. The bottom of the ejector device (4) is fixedly connected to the bottom support plate (12) by an adapter bolt. The top output push rod shaft of the ejector device (4) is inserted into the interior of the fixed mold frame (1). The top of the interior of the fixed mold frame (1) is provided with a moving module (2). The four corners of the moving module (2) are slidably connected to the interior of the fixed mold frame (1). The top center of the moving module (2) is welded to the bottom output push rod shaft of the electric push rod (3).
2. The integral carbon fiber bicycle saddle molding die according to claim 1, characterized in that: The fixed mold frame (1) is provided with a saddle mold (5) at the bottom end of the moving module (2), and the fixed mold frame (1) is provided with four demolding auxiliary parts (6) distributed symmetrically on the axis. The demolding auxiliary parts (6) are attached to the bottom of the output shaft end component of the ejection device (4).
3. The integral carbon fiber bicycle saddle molding die according to claim 2, characterized in that: The fixed mold frame (1) is provided with guide rods (7) at the bottom of the four corners of the top support plate (8). The guide rods (7) are slidably connected to the four corners of the moving module (2). The fixed mold frame (1) is provided with a molding cavity (9). The top opening of the molding cavity (9) is connected to the saddle mold (5). The bottom corners of the molding cavity (9) are provided with mating grooves (10). The demolding auxiliary parts (6) are placed inside the mating grooves (10). The side wall of the mating grooves (10) is provided with mating sliding holes (11). The bottom center of the molding cavity (9) is provided with a cylindrical hole.
4. The integral carbon fiber bicycle saddle molding die according to claim 3, characterized in that: The demolding aid (6) consists of three parts: a first mating plate (16), a second mating plate (18), and five equidistant elastic elements (17). The first mating plate (16) has a mating rod (19) at the top center, which is slidably connected to the mating sliding hole (11). The first mating plate (16) has five equidistant auxiliary rods (20) at the bottom. The second mating plate (18) has an auxiliary cylinder (21) at the top that is slidably connected to the auxiliary rods (20). The outer side of the auxiliary cylinder (21) is provided with elastic elements (17). The two ends of the elastic elements (17) are welded to the opposite ends of the first mating plate (16) and the second mating plate (18), respectively.
5. The integral carbon fiber bicycle saddle molding die according to claim 1, characterized in that: The top output push rod shaft of the ejector device (4) is connected to the central cylindrical hole at the bottom of the molding cavity (9). The top of the ejector device (4) is provided with an ejector plate (13), which is placed at the bottom of the molding cavity (9). The four corners of the bottom of the ejector plate (13) are attached to the top of the mating plate (16). The four corners of the top of the ejector plate (13) are provided with auxiliary ejector rods (14), and the center of the top of the ejector plate (13) is provided with a main ejector rod (15).
6. The integral carbon fiber bicycle saddle molding die according to claim 3, characterized in that: The saddle mold (5) is connected to the top of the molding cavity (9), and a main demolding hole (22) is provided in the center of the saddle mold (5). The main demolding hole (22) is connected to the main ejector rod (15) in a sliding fit. The four corners of the saddle mold (5) are provided with secondary demolding holes (23), which are connected to the secondary ejector rod (14) in a sliding fit.