Mold for flame-retardant conical spring and method for manufacturing flame-retardant conical spring by using mold

Abstract

The invention discloses a mold of a flame-retardant conical spring and a method for manufacturing the flame-retardant conical spring by using the mold. The mold comprises a bottom mold, a lower insert, a middle mold, a fixing plate, a plurality of inner inserts, an upper insert I and an upper insert II, the lower insert is arranged on the bottom die, the outer sleeve, the mandrel and the multiple layers of spacer bushes are all placed on the lower insert, and the middle die is also arranged on the lower insert. When the mold is closed for the first time, the first upper insert is arranged on the middle mold, the fixing plate is arranged on the first upper insert, a multi-layer conventional rubber forming space A is defined by the lower insert, the outer sleeve, the mandrel, the multiple layers of spacer bushes, the first upper insert and the multiple inner inserts, and rubber injection channels are formed in the fixing plate and the first upper insert. Before secondary mold closing, after the first upper insert and the inner insert are taken away, the second upper insert is arranged on the middle mold, the fixing plate is arranged on the second upper insert, a multi-layer fireproof rubber forming space B is defined by the conventional rubber, the outer sleeve, the mandrel, the multiple layers of spacer bushes and the second upper insert, and a rubber injection channel is also formed in the second upper insert.

Description

Technical Field

[0001] The invention relates to a mould and a method for manufacturing a product using the mould, in particular to a mould for a flame retardant conical spring and a method for manufacturing the flame retardant conical spring using the mould, belonging to the technical field of flame retardant conical spring production. Background Art

[0002] Flame retardant conical springs are components that can resist the spread of flames to a certain extent while maintaining their spring function. They are mainly used in situations where fire safety protection is required. Flame retardant conical springs are conical in shape and consist of a conical shell and several conical discs inside. The shape and number of these discs affect the stiffness and working characteristics of the spring. Compared with traditional conical springs, the key to flame retardant conical springs lies in the choice of materials, that is, the use of materials with flame retardant properties.

[0003] like Figure 1 As shown, the flame retardant conical spring is in a cone shape, and includes an outer sleeve 1, a core shaft 2, and a multi-layer spacer 3 disposed between the outer sleeve 1 and the core shaft 2. The outer sleeve 1, the core shaft 2, and the spacer 3 are made of metal parts, and the outer sleeve 1, the core shaft 2, and the multi-layer spacer 3 are vulcanized and bonded together through multiple rubber layers 4. Each rubber layer 4 is composed of two types of rubber, including a conventional rubber 411 located near the large end of the flame retardant conical spring and a fireproof rubber 412 located near the small end of the flame retardant conical spring.

[0004] The Chinese invention patent application with application publication number CN118181642A and application publication date June 14, 2024 discloses a method for forming a flame retardant conical spring, comprising the following steps: S1: preforming an unvulcanized fireproof adhesive layer; S2: bonding the preformed fireproof adhesive layer between adjacent iron parts; S3: preheating the iron parts bonded with the fireproof adhesive layer and placing them into the mold, injecting conventional rubber between the iron parts by high-pressure injection and maintaining the pressure, and forming a conventional adhesive layer on the fireproof adhesive layer; S4: using a conventional rubber vulcanization process to vulcanize the fireproof adhesive layer and the conventional adhesive layer as a whole, and demolding after vulcanization to obtain a flame retardant conical spring.

[0005] It can be seen from the patent document that since the rubber layer of the flame-retardant conical spring includes two types of rubber, conventional rubber and fireproof rubber, in the molding method, it is necessary to first use a mold to preform the fireproof rubber layer, and then preheat the iron parts bonded with the fireproof rubber layer and put them into another mold, and use high-pressure injection to inject conventional rubber between the iron parts to form the conventional rubber layer. Therefore, two sets of molds are required to manufacture the rubber layer of the flame-retardant conical spring, which results in a long manufacturing time for the product, reduces manufacturing efficiency and increases manufacturing costs.

[0006] In summary, how to design a mold for a flame retardant conical spring and a method for manufacturing a flame retardant conical spring using the mold so that the rubber layer of the flame retardant conical spring can be manufactured using the same set of molds, shortening product manufacturing time, improving manufacturing efficiency and reducing manufacturing costs are technical problems that need to be solved urgently. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a mold for a flame retardant conical spring and a method for manufacturing a flame retardant conical spring using the mold in view of the defects existing in the prior art. The mold can use the same set of molds to manufacture the rubber layer of the flame retardant conical spring, shortening the product manufacturing time and improving the manufacturing efficiency. The rubber layer of the flame retardant conical spring can be manufactured using the same set of molds, thereby reducing the manufacturing cost.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: a mold of a flame retardant conical spring, comprising a bottom mold, a lower insert, a middle mold and a fixed plate, which also comprises a plurality of inner inserts, an upper insert one and an upper insert two which can replace the upper insert one; the lower insert is arranged on the bottom mold, the outer sleeve, the core shaft and the multi-layer spacer of the flame retardant conical spring are all placed on the lower insert, the middle mold is also arranged on the lower insert and the middle mold is located at the outer peripheral surface of the outer sleeve of the flame retardant conical spring; During the first mold closing, the upper insert block 1 is arranged on the middle mold, and the upper insert block 1 is used to press the multiple inner inserts to contact the top of the multi-layer spacer of the flame-retardant conical spring. The fixed plate is arranged on the upper insert block 1, and the lower insert block, the outer sleeve of the flame-retardant conical spring, the core shaft and the multi-layer spacer, and the upper insert block 1 and the multiple inner inserts are used to enclose and form a multi-layer conventional rubber molding space A. The fixed plate and the upper insert block 1 are both provided with a glue injection channel, and the multi-layer conventional rubber molding space A is connected to the outside through the glue injection channels on the fixed plate and the upper insert block 1; Before the second mold closing, after the upper insert one and the inner insert are removed, the upper insert two is set on the middle mold, and the fixed plate is set on the upper insert two. The conventional rubber, the outer sleeve of the flame-retardant conical spring, the core shaft and the multi-layer spacer formed in the multi-layer conventional rubber molding space A and the upper insert two are used to form a multi-layer fireproof rubber molding space B. A glue injection channel is also provided on the upper insert two. The multi-layer fireproof rubber molding space B is connected with the outside world through the fixed plate and the glue injection channel on the upper insert two.

[0009] Preferably, the inner insert is annular, and a notch is provided on the inner circumferential surface of the annular inner insert, and the top of the conical spring spacer is obliquely inserted into the notch, so that the inner insert is pressed and contacted on the top of the spacer.

[0010] Preferably, the annular inner insert is a multi-petal split structure.

[0011] Preferably, the annular inner insert of the multi-petal split structure is configured as three petals.

[0012] Preferably, the bottom surface of the inner insert and the bottom surface of the upper insert block 1 enclosed at the upper position of the conventional rubber molding space A are both set to be horizontal planes.

[0013] Preferably, the outlet end of the glue injection channel of the upper insert one is arranged on the horizontal bottom surface of the upper insert one at the upper position enclosed by the conventional rubber molding space A, and the outlet end of the glue injection channel of the upper insert one is connected to the conventional rubber molding space.

[0014] Preferably, a fireproof rubber molding surface is provided on the bottom surface of the upper insert block 2 enclosed above the fireproof rubber molding space B, and an outlet end of the glue injection channel of the upper insert block 2 is provided on the fireproof rubber molding surface.

[0015] The present invention also discloses a method for manufacturing a flame retardant conical spring by using a mold, wherein the mold comprises a bottom mold, a lower insert, a middle mold and a fixed plate, and the mold further comprises a plurality of inner inserts, an upper insert one and an upper insert two which can replace the upper insert one; the method comprises first placing the lower insert on the bottom mold, and then placing the outer sleeve, the core shaft and the multi-layer spacer of the flame retardant conical spring on the lower insert, and then placing the middle mold on the lower insert so that the middle mold is located at the outer peripheral surface of the outer sleeve of the flame retardant conical spring, and then placing the upper insert one on the middle mold, and using the upper insert one to press and contact the plurality of inner inserts on the top of the multi-layer spacer of the flame retardant conical spring, and finally placing the fixed plate on the upper insert one to complete the first mold closing; when the first mold closing is completed, the lower insert, the outer sleeve, the core shaft and the multi-layer spacer of the flame retardant conical spring are A multi-layer conventional rubber molding space A is formed between the sleeve and the upper insert one and multiple inner inserts. At this time, conventional rubber is injected into the multi-layer conventional rubber molding space A through the glue injection channels set on the fixed plate and the upper insert one; then the first mold is opened, the fixed plate, the upper insert one and the inner inserts are taken away, and then the upper insert two is placed on the middle mold, and the fixed plate is placed on the upper insert two to complete the re-mold. When the re-mold is completed, the conventional rubber, the outer sleeve of the flame-retardant conical spring, the core shaft and the multi-layer spacer sleeve and the upper insert two are enclosed to form a multi-layer fireproof rubber molding space B. At this time, fireproof rubber is injected into the multi-layer fireproof rubber molding space B through the glue injection channels set on the fixed plate and the upper insert two, and finally vulcanization is carried out. After the vulcanization is completed, the mold is opened again to complete the manufacture of the flame-retardant conical spring.

[0016] Preferably, the inner insert is annular, and a notch is provided on the inner circumferential surface of the annular inner insert, and the top of the spacer sleeve of the conical spring is obliquely inserted into the notch, and the inner insert is arranged as a multi-petal split structure; when the mold is opened for the first time, the annular inner insert with the multi-petal split structure is taken out radially.

[0017] Preferably, the outlet end of the injection channel of the upper insert two is designed to be staggered with the injection channel itself, and the staggered structure is used to buffer the impact force when the fire-proof rubber is injected, so as to reduce the impact force when the injection channel of the upper insert two injects the fire-proof rubber into the fire-proof rubber molding space B.

[0018] The beneficial effects of the present invention are as follows: the present invention forms a conventional rubber molding space A by using relevant mold parts in the first mold closing process, and forms a fireproof rubber molding space B by only removing the inner insert and replacing the upper insert block 2 in the second mold closing process, thereby using the same set of molds to complete the manufacture of the rubber layer of the flame-retardant conical spring composed of two rubber layers, shortening the product manufacturing time, improving the manufacturing efficiency, and using the same set of molds to manufacture the rubber layer of the flame-retardant conical spring, reducing the manufacturing cost. The annular inner insert is designed as a multi-petal split structure. When it needs to be taken out, the annular inner insert of the multi-petal split structure can be taken out radially, ensuring the normal progress of the manufacturing work. The outlet end of the glue injection channel of the upper insert block 2 is designed to be dislocated with the glue injection channel itself, and the dislocated structure is used to buffer the impact force when the fireproof rubber is injected, so as to reduce the impact force when the glue injection channel of the upper insert block 2 injects the fireproof rubber into the fireproof rubber molding space B, ensuring that the interface between the conventional rubber and the fireproof rubber is close to a straight line state, and improving the quality of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the axial cross-sectional structure of a flame-retardant conical spring; Figure 2 It is a schematic diagram of the axial cross-sectional structure during the first mold closing in an embodiment of the present invention; Figure 3 This is a schematic diagram of the axial cross-sectional structure when the mold is opened for the first time in an embodiment of the present invention; Figure 4 It is a schematic diagram of the axial cross-sectional structure during the second mold closing in an embodiment of the present invention; Figure 5 This is a schematic diagram of the axial cross-sectional structure during the second mold opening in an embodiment of the present invention; Figure 6 for Figure 2 The enlarged structural diagram of the middle C part; Figure 7 for Figure 3 The enlarged structural diagram of the middle D part; Figure 8 for Figure 4 The enlarged structural diagram of the middle E part; In the figure: 1. outer sleeve, 2. mandrel, 3. spacer, 4. rubber layer, 411. conventional rubber, 412. fireproof rubber, 5. bottom mold, 6. lower insert, 7. middle mold, 8. upper insert one, 9. upper insert two, 10. fixing plate, 11. inner insert, 111. notch, 12. glue injection channel, 121. outlet end, 13. horizontal plane. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0021] Example: Figures 2 to 5 As shown, a method for manufacturing a flame retardant conical spring is provided, wherein the mold is designed to include a bottom mold 5, a bottom insert 6, a middle mold 7, an upper insert 8, an upper insert 9 which can replace the upper insert 8, a fixing plate 10, and a plurality of inner inserts 11. During manufacturing, the lower insert 6 is first placed on the bottom mold 5, and then the outer sleeve 1, the core shaft 2, and the multi-layer spacer 3 of the flame retardant conical spring are all placed on the lower insert 6, and then the middle mold 7 is placed on the lower insert 6 so that the middle mold 7 is located at the outer peripheral surface of the outer sleeve 1 of the flame retardant conical spring, and then the upper insert 8 is placed on the inner sleeve 3. On the middle mold 7, the upper insert 8 is used to press the multiple inner inserts 11 into contact with the top of the multi-layer spacer 3 of the flame retardant conical spring, and finally the fixed plate 10 is placed on the upper insert 8 to complete the first mold closing; when the first mold closing is completed, the lower insert 6, the outer sleeve 1 of the flame retardant conical spring, the core shaft 2 and the multi-layer spacer 3, and the upper insert 8 and the multiple inner inserts 11 are surrounded to form a multi-layer conventional rubber molding space A. At this time, conventional rubber is injected into the multi-layer conventional rubber molding space A through the glue injection channel 12 set on the fixed plate 10 and the upper insert 8. Then the mold is opened for the first time, and after the fixed plate 10, the upper insert 8 and the inner insert 11 are removed, the upper insert 9 is placed on the middle mold 7, and the fixed plate 10 is placed on the upper insert 9 to complete the second mold closing. When the second mold closing is completed, the conventional rubber 411, the outer sleeve 1 of the flame retardant conical spring, the core shaft 2 and the multi-layer spacer 3 and the upper insert 9 are enclosed to form a multi-layer fireproof rubber molding space B. At this time, the fireproof rubber 412 is injected into the multi-layer fireproof rubber molding space B through the glue injection channel 12 set on the fixed plate 10 and the upper insert 9. Finally, the conventional rubber and the fireproof rubber are vulcanized. After the vulcanization is completed, the mold is opened again to complete the manufacture of the flame retardant conical spring. In this embodiment, a conventional rubber molding space A is formed by using relevant mold parts during the first mold closing process, and in the second mold closing process, only the inner insert is removed and replaced with the upper insert 2 to form the fire-proof rubber molding space B, thereby using the same set of molds to complete the manufacture of the rubber layer of the flame-retardant conical spring composed of two rubber layers, shortening the product manufacturing time, improving the manufacturing efficiency, and using the same set of molds to manufacture the rubber layer of the flame-retardant conical spring, reducing the manufacturing cost.

[0022] like Figure 6 and Figure 7 As shown, the inner insert 11 is annular, and a notch 111 is provided on the inner circumference of the annular inner insert 11. The top of the spacer 3 of the conical spring is obliquely inserted into the notch 111, so that the inner insert 11 is pressed and contacted on the top of the spacer 3. The inner insert 11 is a multi-petal split structure, and in this embodiment, it is set to three petals. This is because the top of the spacer 3 is obliquely inserted into the inner circumference of the annular inner insert 11, so when the inner insert 11 needs to be taken out during the first mold opening, the inner insert 11 is blocked by the spacer 3 and cannot be taken out vertically upward like the fixed plate 10 and the upper insert 8. Therefore, in this embodiment, the annular inner insert 11 is designed as a multi-petal split structure. When it needs to be taken out, the annular inner insert 11 with a multi-petal split structure can be taken out along the radial direction, ensuring the normal progress of the manufacturing work.

[0023] The bottom surface of the inner insert 11 and the bottom surface of the upper insert 8 enclosed at the upper position of the conventional rubber molding space A are both set to a horizontal plane 13, so that after the conventional rubber 411 is injected into the conventional rubber molding space A, the top surface of the conventional rubber 411 tends to be horizontal, which can improve the quality of the subsequent vulcanization process. The outlet end 121 of the injection channel 12 of the upper insert 8 is set on the horizontal bottom surface of the upper insert 8 enclosed at the upper position of the conventional rubber molding space A, and the outlet end 121 of the injection channel 12 of the upper insert 8 is connected to the conventional rubber molding space A, so that the conventional rubber can be injected into the conventional rubber molding space A by using the injection channel 12.

[0024] like Figure 8 As shown, the bottom surface of the upper insert 9 enclosed above the fireproof rubber molding space B is provided with a fireproof rubber molding surface 911, and the outlet end 121 of the glue injection channel 12 of the upper insert 9 is provided on the fireproof rubber molding surface 911, and the outlet end 121 of the glue injection channel 12 of the upper insert 9 is connected with the fireproof rubber molding space B, so that the fireproof rubber can be injected into the fireproof rubber molding space B by using the glue injection channel 12. Through the shape design of the fireproof rubber molding surface 911, the molding surface of the fireproof rubber can be designed according to the actual working conditions, thereby improving the practicality of this embodiment.

[0025] Since the outlet end 121 of the glue injection channel 12 of the upper insert block 29 is facing the horizontal top surface of the conventional rubber 411, if the impact force when injecting the fire-proof rubber is not reduced at this time, it will cause impact damage to the horizontal top surface of the conventional rubber 411, thereby affecting the quality of the product. Therefore, in this embodiment, the outlet end 121 of the glue injection channel 12 of the upper insert block 29 and the glue injection channel 12 itself are staggered, so that the fire-proof rubber flowing through the glue injection channel 12 will not directly impact into the fire-proof rubber molding space B. The staggered structure is used to buffer the impact force when the fire-proof rubber is injected, so as to reduce the impact force when the glue injection channel 12 of the upper insert block 29 injects the fire-proof rubber into the fire-proof rubber molding space B, thereby ensuring that the interface between the conventional rubber and the fire-proof rubber is close to a straight line state, thereby improving the quality of the product.

[0026] In summary, the present invention forms a conventional rubber molding space A by using relevant mold parts during the first mold closing process, and forms a fireproof rubber molding space B by only removing the inner insert and replacing the upper insert block 2 during the second mold closing process, thereby using the same set of molds to complete the manufacture of the rubber layer of the flame-retardant conical spring composed of two rubber layers, shortening the product manufacturing time, improving the manufacturing efficiency, and using the same set of molds to manufacture the rubber layer of the flame-retardant conical spring, reducing the manufacturing cost. The annular inner insert is designed to be a multi-petal split structure. When it needs to be taken out, the annular inner insert of the multi-petal split structure can be taken out radially, ensuring the normal progress of the manufacturing work. The outlet end of the glue injection channel of the upper insert block 2 is designed to be staggered with the glue injection channel itself, and the staggered structure is used to buffer the impact force when the fireproof rubber is injected, so as to reduce the impact force when the glue injection channel of the upper insert block 2 injects the fireproof rubber into the fireproof rubber molding space B, ensuring that the interface between the conventional rubber and the fireproof rubber is close to a straight line state, and improving the quality of the product.

[0027] The "multiple" mentioned in the embodiments refers to the number of "two or more". The above embodiments are only used to illustrate the present invention, not to limit the present invention. Those skilled in the relevant technical field can make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also belong to the protection scope of the present invention, and the protection scope of the present invention should be defined by the claims.

Claims

1. A mold for a flame retardant conical spring, comprising a bottom mold, a lower insert, a middle mold and a fixing plate, characterized in that: It also includes a plurality of inner inserts, an upper insert block 1 and an upper insert block 2 which can replace the upper insert block 1; the lower insert block is arranged on the bottom mold, the outer sleeve, the core shaft and the multi-layer spacer of the flame retardant conical spring are all placed on the lower insert block, and the middle mold is also arranged on the lower insert block and the middle mold is located at the outer peripheral surface of the outer sleeve of the flame retardant conical spring; During the first mold closing, the upper insert block 1 is arranged on the middle mold, and the upper insert block 1 is used to press the multiple inner inserts to contact the top of the multi-layer spacer of the flame-retardant conical spring. The fixed plate is arranged on the upper insert block 1, and the lower insert block, the outer sleeve of the flame-retardant conical spring, the core shaft and the multi-layer spacer, and the upper insert block 1 and the multiple inner inserts are used to enclose and form a multi-layer conventional rubber molding space A. The fixed plate and the upper insert block 1 are both provided with a glue injection channel, and the multi-layer conventional rubber molding space A is connected to the outside through the glue injection channels on the fixed plate and the upper insert block 1; Before the second mold closing, after the upper insert one and the inner insert are removed, the upper insert two is set on the middle mold, and the fixed plate is set on the upper insert two. The conventional rubber, the outer sleeve of the flame-retardant conical spring, the core shaft and the multi-layer spacer formed in the multi-layer conventional rubber molding space A and the upper insert two are used to form a multi-layer fireproof rubber molding space B. A glue injection channel is also provided on the upper insert two. The multi-layer fireproof rubber molding space B is connected with the outside world through the fixed plate and the glue injection channel on the upper insert two.

2. The mold according to claim 1, characterized in that: The inner insert is annular, and a notch is arranged on the inner circumferential surface of the annular inner insert. The top of the conical spring spacer is obliquely inserted into the notch, so that the inner insert is pressed and contacted on the top of the spacer.

3. The mold according to claim 2, characterized in that: The annular inner insert is a multi-petal split structure.

4. The mold according to claim 3, characterized in that: The annular inner insert of the multi-petal split structure is arranged to have three petals.

5. The mold according to any one of claims 1 to 4, characterized in that: The bottom surface of the inner insert and the bottom surface of the upper insert block 1 enclosed at the upper position of the conventional rubber molding space A are both set to be horizontal planes.

6. The mold according to claim 5, characterized in that: The outlet end of the glue injection channel of the upper insert block 1 is arranged on the horizontal bottom surface of the upper insert block 1 at the upper position enclosed by the conventional rubber molding space A, and the outlet end of the glue injection channel of the upper insert block 1 is connected to the conventional rubber molding space.

7. The mold according to claim 6, characterized in that: The bottom surface of the upper insert block 2 enclosed above the fireproof rubber molding space B is provided with a fireproof rubber molding surface, and the outlet end of the glue injection channel of the upper insert block 2 is provided on the fireproof rubber molding surface.

8. A method for manufacturing a flame retardant conical spring using a mold, the mold comprising a bottom mold, a lower insert, a middle mold and a fixing plate, characterized in that: The mold also includes multiple inner inserts, an upper insert 1 and an upper insert 2 that can replace the upper insert 1; the method is to first place the lower insert on the bottom mold, then place the outer sleeve, core shaft and multi-layer spacer of the flame retardant conical spring on the lower insert, and then place the middle mold on the lower insert so that the middle mold is located at the outer peripheral surface of the outer sleeve of the flame retardant conical spring, and then place the upper insert 1 on the middle mold, and use the upper insert 1 to press the multiple inner inserts to contact the top of the multi-layer spacer of the flame retardant conical spring, and finally place the fixing plate on the upper insert 1 to complete the first mold closing; when the first mold closing is completed, the lower insert, the outer sleeve, core shaft and multi-layer spacer of the flame retardant conical spring, and the upper insert 1 and the multiple inner inserts are enclosed to form a multi-layer constant Conventional rubber molding space A, at this time, conventional rubber is injected into the multi-layer conventional rubber molding space A through the injection channel arranged on the fixed plate and the upper insert one; then the first mold is opened, the fixed plate, the upper insert one and the inner insert are taken away, and then the upper insert two is placed on the middle mold, and the fixed plate is placed on the upper insert two to complete the re-mold closing. When the re-mold closing is completed, the conventional rubber, the outer sleeve of the flame-retardant conical spring, the core shaft and the multi-layer spacer and the upper insert two are enclosed to form a multi-layer fireproof rubber molding space B. At this time, fireproof rubber is injected into the multi-layer fireproof rubber molding space B through the injection channel arranged on the fixed plate and the upper insert two, and finally vulcanization is carried out. After vulcanization is completed, the mold is opened again to complete the manufacture of the flame-retardant conical spring.

9. The method according to claim 8, characterized in that: The inner insert is annular, and a notch is arranged on the inner circumferential surface of the annular inner insert. The top of the conical spring spacer is obliquely inserted into the notch, and the inner insert is arranged as a multi-petal split structure. When the mold is opened for the first time, the annular inner insert with the multi-petal split structure is taken out radially.

10. The method according to claim 8 or 9, characterized in that: The outlet end of the glue injection channel of the upper insert block 2 is designed to be staggered with the glue injection channel itself, and the staggered structure is used to buffer the impact force when the fireproof rubber is injected, so as to reduce the impact force when the glue injection channel of the upper insert block 2 injects the fireproof rubber into the fireproof rubber molding space B.

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