Split core rod

Abstract

The utility model discloses a split type core rod, including the core rod head section of screw connection on the mould body and the core rod tail section through fastening screw locking on the core rod head section, be equipped with the through hole of through both ends of the core rod head section on the core rod head section, and the rod portion of fastening screw passes through the core rod tail section and is connected with the through hole of the core rod head section, and the air hole of through both ends of fastening screw is equipped, and the air hole is linked together with the through hole. This scheme need not dismount the mouth mould and the core rod head section, realize quick replacement core rod, improve the replacement efficiency. Not only omit the step of removing the mouth mould, and the mouth mould and the core rod head section are all in the heating state, only need to wait for the core rod tail section to reheat, can, save the waiting time greatly.

Description

Technical Field

[0001] This utility model relates to the field of extrusion pipe forming technology, and in particular to a split mandrel. Background Technology

[0002] During pipe manufacturing, the gap between the die and the mandrel directly determines the pipe's wall thickness. With technological advancements and market demands, pipes of the same outer diameter and material often require two or more wall thicknesses for different working environments. This is particularly true in the production of PO-type pipes, where pipes of the same outer diameter often have multiple pressure ratings, corresponding to different wall thickness requirements. These pipes with different wall thicknesses but the same outer diameter typically require different die-mandrel gaps. In practical applications, a single die is equipped with multiple mandrels of different specifications. When these mandrels need to be replaced after production, the die must be removed, the mandrels replaced, and the die reinstalled. This process is cumbersome, time-consuming, and results in low production efficiency.

[0003] For example, Chinese Patent Publication No. CN203460410U, published on March 5, 2014, entitled "A PE pipe extrusion die with a mandrel and a die fitted with a bushing", includes a die, a mandrel, a high-temperature resistant die bushing, and a high-temperature resistant mandrel bushing. The mandrel is installed inside the die and forms an extrusion channel with the die. The inner wall of the extrusion end of the die has an annular groove and the high-temperature resistant die bushing is fixedly embedded in the annular groove. The outer wall of the extrusion end of the mandrel has an annular groove and the high-temperature resistant mandrel bushing is fixedly embedded in the annular groove. An extrusion channel is also formed between the high-temperature resistant die bushing and the high-temperature resistant mandrel bushing.

[0004] The drawback of the existing patent is that in the existing production process of pipes with the same outer diameter but different wall thickness, one die is equipped with multiple mandrels of different specifications. When these mandrels need to be replaced with a mandrel of a different specification after production is completed, the die must be removed first, then the mandrels must be replaced, and the die must be reinstalled. This is complicated to disassemble and reassemble, and the replacement time is long, resulting in low production efficiency. Utility Model Content

[0005] The purpose of this invention is to improve the existing production process of pipes with the same outer diameter but different wall thicknesses. When changing mandrels of different specifications using the same die, it is necessary to first remove the die, then replace the mandrel, and then reinstall the die. This process is complicated and time-consuming. The invention provides a split-type mandrel that allows for quick mandrel replacement and improves replacement efficiency.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A split-type mandrel includes a mandrel head section threaded onto a mold body and a mandrel tail section locked to the mandrel head section by fastening screws. The mandrel head section has through holes penetrating both ends. The shank of the fastening screw passes through the mandrel tail section and is threadedly connected to the through holes in the mandrel head section. The fastening screw has vent holes penetrating both ends and communicating with the through holes. This split-type mandrel design improves mandrel replacement efficiency when producing pipes of different wall thicknesses using the same mold. The split-type mandrel allows for quick mandrel replacement without removing the mold. The mandrel head is threaded onto the mold body, and the mandrel tail is fixed to the mandrel head with fastening screws. After producing one type of pipe, it is necessary to replace it with a mandrel of a different specification to create a new die-mandrel gap. Simply unscrew the fastening screws, remove the mandrel tail from the die's outlet end, insert the mandrel tail with the desired gap into the die, and lock it to the original mandrel head with the fastening screws. This eliminates the need to disassemble the die and mandrel head, enabling quick mandrel replacement and improving efficiency. Not only does it eliminate the need to remove the die, but both the die and mandrel head are heated; only the mandrel tail needs to reheat, significantly reducing waiting time. The through hole and vent hole connect the two ends of the mandrel head and tail assembly, ensuring internal air permeability of the mandrel.

[0007] Preferably, the through hole has a countersunk hole at one end facing the tail section of the mandrel. The head section of the mandrel also has a countersunk hole, which facilitates locking the head section of the mandrel onto the mold body.

[0008] Preferably, the mandrel head section has a positioning groove at one end facing the mandrel tail section, and the mandrel tail section has a positioning post at one end facing the mandrel head section. The inner peripheral wall of the positioning groove and the outer peripheral wall of the positioning post cooperate with each other. The cooperation between the inner peripheral wall of the positioning groove and the outer peripheral wall of the positioning post serves a positioning function.

[0009] Preferably, the depth of the positioning groove is greater than the thickness of the positioning post. A gap is provided between the bottom of the positioning groove and the end face of the positioning post to prevent gaps from forming at the connection between the head and tail sections of the mandrel after heating.

[0010] Preferably, the mandrel head section has a positioning part at one end away from the mandrel tail section, and the positioning part has a connecting part. The outer peripheral wall of the connecting part has an external thread that connects with the mold body. The external thread of the connecting part of the mandrel head and the external thread of the fastening screw have the same direction of rotation to prevent the mandrel head from being loosened while tightening the fastening screw.

[0011] Preferably, the outer diameter of the end of the mandrel head facing the mandrel tail is the same as the outer diameter of the end of the mandrel tail facing the mandrel head. This prevents a stepped surface from appearing at the junction of the mandrel head and tail. The mandrel tail is selected so that it can be removed from the die's outlet end. The outer diameter of the end of the mandrel tail facing the mandrel head should be based on the minimum diameter of the mandrel tail as the diameter of the connecting surface. This ensures that the section of the mandrel tail furthest from the mandrel head is effectively compressed, rather than suddenly expanded. Sudden expansion would cause changes in internal pressure, affecting product quality and performance.

[0012] Preferably, the fastening screw is an internal hex screw, which facilitates tightening.

[0013] Preferably, the internal hexagon countersunk hole is coaxially arranged with the mandrel head section.

[0014] Preferably, the vent extends along the axial direction of the fastening screw and is coaxially arranged with the fastening screw.

[0015] Preferably, the mandrel head section and the mandrel tail section are coaxially arranged, and the fastening screw is coaxially arranged with the mandrel tail section.

[0016] Therefore, this utility model has the following beneficial effects: it eliminates the need to disassemble the die and mandrel head, enabling rapid mandrel replacement and improving replacement efficiency. Not only does it eliminate the step of removing the die, but both the die and mandrel head are already heated; one only needs to wait for the mandrel tail to reheat, greatly saving waiting time. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model.

[0018] Figure 2 This is a schematic diagram of the structure of the core rod head section in this utility model.

[0019] Figure 3 This is a cross-sectional view of the mandrel head section in this utility model.

[0020] As shown in the picture: Mandrel head section 1, through hole 1.1, internal hexagon countersunk hole 1.2, positioning groove 1.3, positioning part 1.4, connecting part 1.5 Mandrel tail section 2, positioning post 2.1 3. Fastening screws, 3.1. Vent holes. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the utility model will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0022] Example 1, as Figure 1 , Figure 2 , Figure 3 The illustrated split mandrel includes a mandrel head section 1 threaded onto the mold body and a mandrel tail section 2 locked onto the mandrel head section 1 by a fastening screw 3. The mandrel head section 1 is provided with a through hole 1.1 penetrating both ends of the mandrel head section 1. The shank of the fastening screw 3 passes through the mandrel tail section 2 and is threadedly connected to the through hole 1.1 of the mandrel head section 1. The fastening screw 3 is provided with a vent hole 3.1 penetrating both ends of the fastening screw 3, and the vent hole 3.1 communicates with the through hole 1.1.

[0023] During pipe manufacturing, the gap between the die and the mandrel directly determines the pipe's wall thickness. With technological advancements and market demands, pipes of the same outer diameter and material often require two or more wall thicknesses for different working environments. This is particularly true in the production of PO-type pipes, where pipes of the same outer diameter often have multiple pressure ratings, corresponding to different wall thickness requirements. These pipes with different wall thicknesses but the same outer diameter typically require different die-mandrel gaps. In practical applications, a single die is equipped with multiple mandrels of different specifications. When these mandrels need to be replaced after production, the die must be removed, the mandrels replaced, and the die reinstalled. This process is cumbersome, time-consuming, and results in low production efficiency.

[0024] To improve the current production process of pipes with the same outer diameter but different wall thicknesses, when changing mandrels of different specifications using the same die, it is necessary to first remove the die, then replace the mandrel, and then reinstall the die, which is complicated and time-consuming. Therefore, a split-type mandrel is provided to quickly replace the mandrel and improve the replacement efficiency.

[0025] One of the split-type mandrels in the above embodiments, such as Figure 1 , Figure 2 , Figure 3As shown, this design facilitates improved mandrel replacement efficiency when producing pipes of different wall thicknesses using the same die. The split-type mandrel allows for quick mandrel replacement without removing the die. The mandrel head section 1 is threaded onto the die body, and the mandrel tail section 2 is fixed to the mandrel head section 1 by fastening screws 3. After producing one type of pipe, it is necessary to replace the mandrel with a different specification to create a new die-mandrel gap. Simply unscrew the fastening screws 3, remove the mandrel tail section 2 from the die's outlet, insert the mandrel tail section 2 (creating the different die-mandrel gaps) into the die, and lock it to the original mandrel head section 1 with the fastening screws 3. This eliminates the need to disassemble the die and mandrel head section 1, enabling rapid mandrel replacement and improving efficiency. Not only does it eliminate the need to remove the die, but both the die and mandrel head section 1 are heated; only the mandrel tail section 2 needs to be heated again, significantly reducing waiting time. Through hole 1.1 and vent hole 3.1 connect the two ends of the mandrel head section 1 and mandrel tail section 2 assembly to ensure the internal air permeability of the mandrel.

[0026] Further optimizations were made to fastening screw 3, such as... Figure 1 As shown, fastening screw 3 is an internal hex screw. This makes it easy to tighten fastening screw 3.

[0027] Further optimizations were made to the internal hexagon countersunk hole 1.2, such as... Figure 1 , Figure 2 , Figure 3 As shown, the internal hexagon countersunk hole 1.2 is coaxially arranged with the mandrel head section 1.

[0028] Further optimization of vent 3.1, such as... Figure 1 , Figure 2 , Figure 3 As shown, the vent 3.1 extends along the axial direction of the fastening screw 3 and is coaxially arranged with the fastening screw 3.

[0029] Further optimizations were made to the mandrel head and mandrel tail, such as... Figure 1 As shown, the mandrel head section 1 and the mandrel tail section 2 are coaxially arranged, and the fastening screw 3 is coaxially arranged with the mandrel tail section 2.

[0030] Example 2, as Figure 1 , Figure 2 , Figure 3 The illustrated split mandrel includes a mandrel head section 1 threaded onto the mold body and a mandrel tail section 2 locked onto the mandrel head section 1 by a fastening screw 3. The mandrel head section 1 is provided with a through hole 1.1 penetrating both ends of the mandrel head section 1. The shank of the fastening screw 3 passes through the mandrel tail section 2 and is threadedly connected to the through hole 1.1 of the mandrel head section 1. The fastening screw 3 is provided with a vent hole 3.1 penetrating both ends of the fastening screw 3, and the vent hole 3.1 communicates with the through hole 1.1.

[0031] In this embodiment, a countersunk hole 1.2 is provided at one end of the through hole 1.1 facing the tail section 2 of the mandrel. The head section 1 of the mandrel is provided with a countersunk hole 1.2, which facilitates the operation of locking the head section 1 of the mandrel onto the mold body.

[0032] Further optimization was made to the connection between the mandrel head and the mandrel tail, such as... Figure 1 As shown, a positioning part 1.4 is provided at the end of the mandrel head section 1 away from the mandrel tail section 2. A connecting part 1.5 is provided on the positioning part 1.4. The outer peripheral wall of the connecting part 1.5 is provided with an external thread that connects with the mold body. The external thread of the connecting part 1.5 at the mandrel head and the external thread of the fastening screw 3 have the same direction of rotation to prevent the mandrel head from being loosened while tightening the fastening screw 3.

[0033] Further optimization was made to the connection between the mandrel head and the mandrel tail, such as... Figure 1 As shown, the outer diameter of the end of the mandrel head section 1 facing the mandrel tail section 2 is the same as the outer diameter of the end of the mandrel tail section 2 facing the mandrel head section 1. This prevents a stepped surface from appearing at the junction of the mandrel head and tail. The mandrel tail section 2 is selected based on its ability to be removed from the die's discharge end. The outer diameter of the end of the mandrel tail section 2 facing the mandrel head section 1 should be based on the minimum diameter of the mandrel tail section 2 as the diameter of the connecting surface. This ensures that the section of the mandrel tail section 2 away from the mandrel head section 1 is effectively compressed, rather than suddenly expanded. Sudden expansion would cause changes in internal pressure, affecting product quality and performance.

[0034] Further optimizations were made to fastening screw 3, such as... Figure 1 As shown, fastening screw 3 is an internal hex screw. This makes it easy to tighten fastening screw 3.

[0035] Further optimizations were made to the internal hexagon countersunk hole 1.2, such as... Figure 1 , Figure 2 , Figure 3 As shown, the internal hexagon countersunk hole 1.2 is coaxially arranged with the mandrel head section 1.

[0036] Further optimization of vent 3.1, such as... Figure 1 , Figure 2 , Figure 3 As shown, the vent 3.1 extends along the axial direction of the fastening screw 3 and is coaxially arranged with the fastening screw 3.

[0037] Further optimizations were made to the mandrel head and mandrel tail, such as... Figure 1 As shown, the mandrel head section 1 and the mandrel tail section 2 are coaxially arranged, and the fastening screw 3 is coaxially arranged with the mandrel tail section 2.

[0038] like Figure 1 , Figure 2 , Figure 3As shown, in the existing production process of pipes with the same outer diameter but different wall thicknesses, a single die is equipped with multiple mandrels of different specifications. When a different specification of mandrel needs to be replaced after production, the die must be removed, the mandrel replaced, and the die reinstalled. This process is cumbersome and time-consuming, resulting in low production efficiency. To improve the existing process of producing pipes with the same outer diameter but different wall thicknesses, where replacing mandrels with different specifications requires removing the die, replacing the mandrel, and reinstalling the die, a separate mandrel design is provided for quick mandrel replacement and improved efficiency. This embodiment eliminates the need to disassemble the die and mandrel head section 1, enabling quick mandrel replacement and improving efficiency. Not only is the step of removing the die eliminated, but both the die and mandrel head section 1 are heated, requiring only waiting for the mandrel tail section 2 to reheat, significantly reducing waiting time.

[0039] Example 3, as Figure 1 , Figure 2 , Figure 3 The illustrated split mandrel includes a mandrel head section 1 threaded onto the mold body and a mandrel tail section 2 locked onto the mandrel head section 1 by a fastening screw 3. The mandrel head section 1 is provided with a through hole 1.1 penetrating both ends of the mandrel head section 1. The shank of the fastening screw 3 passes through the mandrel tail section 2 and is threadedly connected to the through hole 1.1 of the mandrel head section 1. The fastening screw 3 is provided with a vent hole 3.1 penetrating both ends of the fastening screw 3, and the vent hole 3.1 communicates with the through hole 1.1.

[0040] In this embodiment, as Figure 1 , Figure 2 , Figure 3 As shown, a positioning groove 1.3 is provided at the end of the mandrel head section 1 facing the mandrel tail section 2, and a positioning post 2.1 is provided at the end of the mandrel tail section 2 facing the mandrel head section 1. The inner peripheral wall of the positioning groove 1.3 and the outer peripheral wall of the positioning post 2.1 are fitted together. The fit between the inner peripheral wall of the positioning groove 1.3 and the outer peripheral wall of the positioning post 2.1 serves a positioning function.

[0041] Further optimization was made to the connection between the mandrel head and the mandrel tail, such as... Figure 1 As shown, the depth of the positioning groove 1.3 is greater than the thickness of the positioning post 2.1. A gap is provided between the bottom of the positioning groove 1.3 and the end face of the positioning post 2.1 to prevent gaps from forming at the connection between the head section 1 and the tail section 2 of the mandrel after heating.

[0042] Further optimization of the mandrel head, such as Figure 1 , Figure 2 , Figure 3 As shown, the end of the through hole 1.1 facing the tail section 2 of the mandrel is provided with an internal hexagon countersunk hole 1.2. The mandrel head section 1 is provided with an internal hexagon countersunk hole 1.2, which facilitates the operation of locking the mandrel head section 1 onto the mold body.

[0043] Further optimization was made to the connection between the mandrel head and the mandrel tail, such as... Figure 1 As shown, a positioning part 1.4 is provided at the end of the mandrel head section 1 away from the mandrel tail section 2. A connecting part 1.5 is provided on the positioning part 1.4. The outer peripheral wall of the connecting part 1.5 is provided with an external thread that connects with the mold body. The external thread of the connecting part 1.5 at the mandrel head and the external thread of the fastening screw 3 have the same direction of rotation to prevent the mandrel head from being loosened while tightening the fastening screw 3.

[0044] Further optimization was made to the connection between the mandrel head and the mandrel tail, such as... Figure 1 As shown, the outer diameter of the end of the mandrel head section 1 facing the mandrel tail section 2 is the same as the outer diameter of the end of the mandrel tail section 2 facing the mandrel head section 1. This prevents a stepped surface from appearing at the junction of the mandrel head and tail. The mandrel tail section 2 is selected based on its ability to be removed from the die's discharge end. The outer diameter of the end of the mandrel tail section 2 facing the mandrel head section 1 should be based on the minimum diameter of the mandrel tail section 2 as the diameter of the connecting surface. This ensures that the section of the mandrel tail section 2 away from the mandrel head section 1 is effectively compressed, rather than suddenly expanded. Sudden expansion would cause changes in internal pressure, affecting product quality and performance. Different specifications of mandrel tail sections 2 are selected so that the gap between the mandrel tail section 2 and the die remains constant or gradually decreases along the axial direction of the mandrel tail section 2 away from the mandrel head section 1. This ensures that the section of the mandrel tail section 2 away from the mandrel head section 1 is effectively compressed, rather than suddenly expanded, thereby improving product quality and preventing the problem of localized substandard pipe quality caused by sudden expansion of the die-mandrel gap leading to changes in internal pressure.

[0045] Further optimizations were made to fastening screw 3, such as... Figure 1 As shown, fastening screw 3 is an internal hex screw. This makes it easy to tighten fastening screw 3.

[0046] Further optimizations were made to the internal hexagon countersunk hole 1.2, such as... Figure 1 , Figure 2 , Figure 3 As shown, the internal hexagon countersunk hole 1.2 is coaxially arranged with the mandrel head section 1.

[0047] Further optimization of vent 3.1, such as... Figure 1 , Figure 2 , Figure 3 As shown, the vent 3.1 extends along the axial direction of the fastening screw 3 and is coaxially arranged with the fastening screw 3.

[0048] Further optimizations were made to the mandrel head and mandrel tail, such as... Figure 1 As shown, the mandrel head section 1 and the mandrel tail section 2 are coaxially arranged, and the fastening screw 3 is coaxially arranged with the mandrel tail section 2.

[0049] In the existing production process of pipes with the same outer diameter but different wall thicknesses, a single die is equipped with multiple mandrels of different specifications. When a different specification mandrel needs to be replaced after production, the die must be removed, the mandrel replaced, and the die reinstalled. This process is cumbersome, time-consuming, and results in low production efficiency. To improve this process, a split-type mandrel design is proposed for faster mandrel replacement and increased efficiency. Figure 1 , Figure 2 , Figure 3 As shown, this embodiment eliminates the need to disassemble the die and mandrel head 1, enabling rapid mandrel replacement and improving replacement efficiency. Not only is the step of removing the die eliminated, but both the die and mandrel head 1 are already heated; only the mandrel tail 2 needs to be heated again, significantly reducing waiting time.

[0050] The specific embodiments described above are merely preferred embodiments of this utility model and are not intended to limit the specific scope of implementation of this utility model. All equivalent changes made to the shape and structure of this utility model should be included within the protection scope of this utility model.

Claims

1. A split-type mandrel, characterized in that, It includes a mandrel head section threaded onto the mold body and a mandrel tail section locked onto the mandrel head section by a fastening screw. The mandrel head section has a through hole that passes through both ends of the mandrel head section. The shank of the fastening screw passes through the mandrel tail section and is threadedly connected to the through hole of the mandrel head section. The fastening screw has a vent hole that passes through both ends of the fastening screw and is connected to the through hole.

2. A split-type mandrel according to claim 1, characterized in that, The through hole has an internal hexagonal countersunk hole at one end facing the tail section of the mandrel.

3. A split-type mandrel according to claim 2, characterized in that, The head section of the mandrel is provided with a positioning groove at one end facing the tail section of the mandrel, and the tail section of the mandrel is provided with a positioning post at one end facing the head section of the mandrel. The inner peripheral wall of the positioning groove and the outer peripheral wall of the positioning post are engaged.

4. A split-type mandrel according to claim 3, characterized in that, The depth of the positioning groove is greater than the thickness of the positioning post.

5. A split-type mandrel according to claim 1, 2, 3, or 4, characterized in that, The mandrel head section is provided with a positioning part at one end away from the mandrel tail section, the positioning part is provided with a connecting part, and the outer peripheral wall of the connecting part is provided with an external thread that is threaded to the mold body.

6. A split-type mandrel according to claim 1, 2, 3, or 4, characterized in that, The outer diameter of the end of the mandrel head section facing the mandrel tail section is the same as the outer diameter of the end of the mandrel tail section facing the mandrel head section.

7. A split-type mandrel according to claim 1, 2, 3, or 4, characterized in that, The fastening screw is an internal hex screw.

8. A split-type mandrel according to claim 2, 3, or 4, characterized in that, The internal hexagon countersunk hole is coaxially arranged with the head section of the mandrel.

9. A split-type mandrel according to claim 1, 2, 3, or 4, characterized in that, The vent extends along the axial direction of the fastening screw and is coaxially arranged with the fastening screw.

10. A split-type mandrel according to claim 1, 2, 3, or 4, characterized in that, The head section and tail section of the mandrel are coaxially arranged, and the fastening screw is coaxially arranged with the tail section of the mandrel.

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