A quick-change pin structure for moving and stationary mold cores

Abstract

This utility model discloses a quick-change pin structure for moving and fixed mold cores. It is applied to the mold cores of moving and fixed molds and includes a pin. The pin includes a forming part and a threaded fixing part. A threaded mounting hole adapted to the threaded fixing part is provided on the mold core. The threaded fixing part of the pin is screwed into the threaded mounting hole on the mold core from the front side of the mold core, and the forming part of the pin is located on the front side of the mold core. The advantages are that the structure is extremely simplified and the operation is very convenient. The pin can be quickly installed, locked and quickly changed from the front side of the mold core, which greatly improves the product production efficiency.

Description

Technical Field

[0001] This utility model relates to the field of mold technology, and in particular to a quick-change pin structure for moving and fixed mold cores used in die casting, injection molding and other molds. Background Technology

[0002] In mold manufacturing, the moving and fixed mold cores are equipped with pins of various functions (such as forming pins and positioning pins). These pins are prone to breakage or wear under harsh working conditions of long-term impact and abrasion, requiring frequent replacement. To achieve rapid pin replacement, various solutions have been developed in the existing technology.

[0003] A traditional quick-change pin structure includes several pins housed within the mold core, several quick-change rods positioned between the mold frame and the mold base, and a bottom plate on the back of the mold base. One end of each quick-change rod passes through the mold frame and is detachably connected to the tail of the pin; the other end passes through the mold base and is detachably connected to the bottom plate. To change a pin, the operator must first remove the bottom plate and then perform the pin replacement operation on the back of the mold base. However, after the mold is installed, there is insufficient operating space between the back of the mold base and the die-casting machine template. Therefore, performing a quick-change operation requires lifting the entire mold set off the die-casting machine (i.e., "molding down"). This renders the term "quick change" meaningless, as the entire process is time-consuming and severely impacts production efficiency.

[0004] Subsequently, many improvements were proposed. For example, a utility model patent published in China (CN205519565U) discloses a quick-change structure for casting pins in die-casting molds. This structure solves the problem of quickly changing the connecting casting pins between the bottom mold, mold frame, and mold core during die-casting mold production. The structure includes a mold frame and a mold core positioned on the upper part of the mold frame. Its key feature is that several casting pins are provided at the mating point between the bottom surface of the mold core and the supporting surface of the mold frame. The casting pins have a stepped shaft structure, with the lower section of the casting pin located in the positioning through hole of the mold frame. A stud screw is provided below the casting pin, and the stud screw engages with the inner nut in the positioning through hole of the mold frame. When changing the casting pins, it is not necessary to disassemble the mold; only the stud screw needs to be unscrewed, greatly saving mold assembly costs and improving product production efficiency. This structure eliminates the need for a quick-change rod, uses stepped shaft-shaped casting pins, and locks them from the back of the mold frame using stud screws. While this simplifies the structure, it still relies heavily on the operating space on the "back of the mold." In actual production, when the operating space between the back of the mold frame and the front of the mold base is extremely limited, disassembling and assembling the stud head screws and casting pins is very difficult, resulting in low replacement efficiency. It may even be necessary to remove the mold before replacing the casting pins. Furthermore, even when there is sufficient operating space between the back of the mold frame and the front of the mold base, complex molds often have cooling water circuits, oil line connectors, sensor lines, etc., around the back of the mold frame and the mold base. These pipes and lines can severely hinder operators from using wrenches and other tools to loosen or tighten the stud head screws. Therefore, before replacing the casting pins, it may be necessary to disassemble these surrounding pipes and lines first. The time spent disassembling and assembling the pipes and lines far exceeds that spent replacing the casting pins themselves, which is time-consuming and laborious, and can easily introduce new risks.

[0005] Therefore, there is an urgent need in this field for a pin quick-change structure that can fundamentally solve the above problems and achieve true rapid pin replacement. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a pin quick-change structure for moving and fixed mold cores that is extremely simplified in structure and very easy to operate. It can quickly install, lock, and change the pins from the front of the mold core, which greatly improves product production efficiency.

[0007] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: a quick-change pin structure for moving and fixed mold cores, which is applied to the mold cores of moving and fixed molds, and includes a pin, characterized in that: the pin includes a forming part and a threaded fixing part, the mold core is provided with a threaded mounting hole adapted to the threaded fixing part, the threaded fixing part is screwed into the threaded mounting hole from the front of the mold core, and the forming part is located on the front of the mold core.

[0008] Preferably, the pin further includes a mounting neck integrally connected to the molding end face of the molding part. The mounting neck is provided with a pre-fabricated break and a driving part for applying force to the tool. When the pin is tightened by the driving part, the mounting neck can break off from the molding part at the pre-fabricated break. In this structure, to achieve the core objective of completing the pin installation from the front of the mold core and ultimately ensuring a flat mold closing surface, a mounting neck with a pre-fabricated break is innovatively designed. During the installation stage, since the pin ultimately needs to be sunk into the mold core and use the flat end face as the molding end face, its molding part itself cannot provide an interface for tool clamping. Therefore, the mounting neck acts as a one-time torque transmission intermediary at this stage. Through its driving part, the rotational torque of the tool is effectively transmitted to the threaded fixing part of the pin, so that it is fully tightened and a stable connection is obtained. After installation, the mounting neck is precisely broken off through its preset weak point (pre-fabricated break), actively removing the temporary installation structure and eliminating all risks of mold closing interference.

[0009] Preferably, the minimum cross-sectional area at the pre-formed fracture is one-third to two-thirds of the area of ​​the formed end face of the formed part. In this structure, the proportional range of the pre-formed fracture area was obtained through extensive testing. This proportional range ensures that the breaking torque of the mounting neck is greater than the tightening torque required for the threaded fixing part of the pin, thereby ensuring that the mounting neck only breaks at the pre-formed fracture after the pin is fully tightened and obtains sufficient preload.

[0010] Preferably, the driving part is a polygonal blind hole formed on the free end of the mounting neck. In this structure, using a polygonal blind hole as the driving part is a torque transmission scheme that is simple in structure, has readily available standard tools, and is easy to operate; specifically, it can be designed as an internal hexagonal hole.

[0011] Preferably, the pin further includes a smooth rod reinforcement portion disposed between the forming portion and the threaded fixing portion, and the mold core also has a smooth hole adapted to the smooth rod reinforcement portion and coaxial with the threaded mounting hole. In this structure, the cooperation between the smooth rod reinforcement portion and the smooth hole provides additional radial support and positioning for the pin, enhances the pin's ability to resist bending stress, and improves the pin's accuracy and lifespan, making it particularly suitable for applications subject to lateral forces.

[0012] Compared with the prior art, the advantages of this utility model are: By screwing the threaded fixing part of the pin into the threaded mounting hole on the mold core from the front, the pin is installed and locked onto the mold core. This allows all installation and disassembly operations to be performed from the front of the mold, completely eliminating the reliance on the operating space on the back of the mold. This enables the pin to be replaced quickly with the help of tools without removing the mold from the die-casting machine (without removing the mold), thus greatly saving mold change time and improving product production efficiency.

[0013] This quick-change pin structure is simple, and the pin is easily installed by simply screwing the threaded fixing part of the pin into the threaded mounting hole on the mold core. When the pin needs to be replaced due to breakage, since its remains are located in the threaded mounting hole on the mold core, maintenance personnel can directly access it from the front of the mold using a standard broken screw removal tool. Compared to traditional quick-change pin structures that require removing the mold when replacing the pin, this greatly reduces maintenance difficulty and shortens downtime. Compared to the casting pin quick-change structure of CN205519565U, which is difficult to operate when replacing the pin and may still require removing the mold, and in complex molds, requires disassembling pipes and wiring first, this structure also greatly reduces maintenance difficulty and shortens downtime. Attached Figure Description

[0014] Figure 1 A three-dimensional structural diagram of the pin; Figure 2 for Figure 1 Axial sectional view; Figure 3 for Figure 2 The right view; Figure 4 This is an axial sectional view after the pin is installed on the mold core. Detailed Implementation

[0015] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings. The scope of protection of this utility model should not be limited to the description of this embodiment.

[0016] A mold typically consists of a moving mold and a fixed mold. Both the moving mold and the fixed mold include a mold base and a mold frame 9 fixed to the front of the mold base (see [link]). Figure 4 The mold core 8 is located inside the cavity of the mold frame 9 (see...). Figure 4 This utility model proposes a quick-change pin structure for moving and fixed mold cores, such as... Figures 1 to 4As shown, it is applied to the mold core 8 of the moving mold and the fixed mold. It includes a pin 1, which includes a forming part 11 and a threaded fixing part 12. The mold core 8 has a threaded mounting hole 81 that matches the threaded fixing part 12. The threaded fixing part 12 of the pin 1 is screwed into the threaded mounting hole 81 on the mold core 8 from the front side. The forming part 11 of the pin 1 is located on the front side of the mold core 8. By screwing the threaded fixing part 12 of the pin 1 into the threaded mounting hole 81 on the mold core 8 from the front side of the mold core 8, the pin 1 is installed and locked on the mold core 8. This allows all installation and disassembly operations to be performed on the front side of the mold, which completely eliminates the dependence on the operating space on the back side of the mold. This allows the pin 1 to be quickly replaced with tools without disassembling the mold and removing it from the die-casting machine (without removing the mold), thereby greatly saving mold change time and improving product production efficiency. This quick-change pin structure is simple, and when installing pin 1, simply screw the threaded fixing part 12 of pin 1 into the threaded mounting hole 81 on the mold core 8, which is extremely convenient. When pin 1 needs to be replaced due to breakage, since its remains are located in the threaded mounting hole 81 on the mold core 8, maintenance personnel can directly handle it from the front of the mold using a standard broken screw removal tool. Compared with the traditional quick-change pin structure, which requires removing the mold when replacing pins, this greatly reduces maintenance difficulty and shortens downtime. Compared with the casting pin quick-change structure of CN205519565U, which is difficult to operate when replacing pins and may still require removing the mold, and disassembling pipelines and wiring in complex molds, this structure also greatly reduces maintenance difficulty and shortens downtime.

[0017] Preferably, the pin 1 further includes a mounting neck 14 integrally connected to the forming end face 111 of the forming part 11. The mounting neck 14 is provided with a pre-cut break 141 and a driving part 142 for applying force to the tool. When the pin 1 is tightened by the driving part 142, the mounting neck 14 can be separated from the forming part 11 at the pre-cut break 141. In this structure, in order to achieve the core objective of completing the installation of the pin 1 from the front of the mold core 8 and finally ensuring the flatness of the mold closing surface, the mounting neck 14 with the pre-cut break 141 is innovatively provided. During the installation stage, since the pin 1 ultimately needs to be sunk into the mold core 8 and use the flat end face as the forming end face, its forming part 11 itself cannot provide an interface for the tool to clamp. Therefore, the mounting neck 14 acts as a one-time torque transmission medium at this stage. Through its driving part 142, the rotational torque of the tool is effectively transmitted to the threaded fixing part 12 of the pin 1, so that it is fully tightened and a stable connection is obtained. After installation, the installation neck 14 is precisely severed through its pre-designed weak point (prefabricated break 141), actively removing the temporary installation structure and eliminating all risks of mold closing interference.

[0018] Preferably, the minimum cross-sectional area at the pre-fabricated fracture 141 is precisely designed to be one-third to two-thirds of the area of ​​the molded end face 111 of the molding part 11. In this structure, the proportional range of the area of ​​the pre-fabricated fracture 141 is obtained through extensive testing. This proportional range ensures that the breaking torque of the mounting neck 14 is greater than the tightening torque required by the threaded fixing part 12 of the pin 1, thereby ensuring that the mounting neck 14 only breaks at the pre-fabricated fracture 141 after the pin 1 is fully tightened and obtains sufficient preload.

[0019] Preferably, the drive part 142 is a polygonal blind hole formed on the free end of the mounting neck 14. In this structure, using a polygonal blind hole as the drive part 142 is a torque transmission solution that is simple in structure, has readily available standard tools, and is easy to operate; specifically, it can be designed as an internal hexagonal hole.

[0020] Preferably, the pin 1 further includes a smooth rod reinforcing part 13 disposed between the forming part 11 and the threaded fixing part 12, and the mold core 8 also has a smooth hole 82 that is adapted to the smooth rod reinforcing part 13 and coaxial with the threaded mounting hole 81. In this structure, the cooperation between the smooth rod reinforcing part 13 and the smooth hole 82 provides additional radial support and positioning for the pin 1, enhances the pin 1's ability to resist bending stress, and improves the pin 1's accuracy and service life, making it particularly suitable for working conditions subject to lateral forces.

[0021] In this embodiment, the pin 1 is preferably made of alloy tool steel and heat-treated, and its threaded fixing part 12, smooth rod reinforcing part 13, forming part 11, and mounting neck 14 are sequentially connected and integrally formed.

[0022] In this embodiment, the mounting neck 14 has a three-section structure: a constricted tail section 143 connected to the molded end face 111 of the molding part 11, a middle tapered section 144 that provides reinforcement, and an outermost wide head section 145. A hexagonal hole is provided on the free end face of the wide head section 145 as a driving part 142. The annular end face of the constricted tail section 143 connected to the molding part 11 is the area where the pre-fabricated break 141 is located. The central axis of the pin body (composed of the threaded fixing part 12, the smooth rod reinforcing part 13, and the molding part 11) is strictly aligned with the central axis of the mounting neck 14 to ensure smooth torque transmission.

[0023] The installation process for pin 1 is as follows: The operator uses an Allen wrench that matches the Allen socket to align the threaded fixing part 12 of the pin 1 with the threaded mounting hole 81 on the mold core 8 from the front. During this process, the smooth reinforcing part 13 of the pin 1 forms a precise fit with the corresponding smooth hole 82 on the mold core 8, providing radial support. When the pin 1 is tightened to the correct position, i.e., the forming part 11 reaches the predetermined position and the threaded pair receives sufficient preload, the rotational torque is continuously and uniformly increased. Since the mounting neck 14 rotates coaxially with the pin body, the torque is directly transmitted and highly concentrated at the pre-cut fracture 141, resulting in significant stress concentration in this area. When the applied torque causes the shear stress generated at the pre-cut fracture 141 to exceed the shear strength limit of the material itself, the mounting neck 14 will be precisely twisted off at this pre-cut fracture 141.

[0024] The replacement process for pin 1 is as follows: When pin 1 needs to be replaced (whether for normal replacement or replacement due to breakage), the operator should always operate from the front of the mold core 8. For a broken pin 1, the remaining end of its threaded fixing part 12 is still inside the threaded mounting hole 81. At this time, a standard broken screw removal tool (such as a left-hand drill bit and a broken screw extractor) can be used to unscrew it. The entire replacement process does not require lifting the mold off the die-casting machine (without removing the mold), achieving a truly online quick replacement and greatly shortening maintenance downtime.

Claims

1. A pin quick change structure for movable and fixed mold cores, which is applied to the mold cores of a movable mold and a fixed mold, comprising a pin, characterized in that: The pin includes a forming part and a threaded fixing part. The mold core has a threaded mounting hole that is adapted to the threaded fixing part. The threaded fixing part is screwed into the threaded mounting hole from the front of the mold core. The forming part is located on the front of the mold core.

2. The quick-change pin structure for a moving and fixed mold core according to claim 1, characterized in that: The pin also includes a mounting neck integrally connected to the molded end face of the molding part. The mounting neck is provided with a pre-cut break and a driving part for applying force to a tool. When the pin is tightened by the driving part, the mounting neck can be separated from the molding part at the pre-cut break.

3. A quick-change pin structure for a moving and fixed mold core according to claim 2, characterized in that: The minimum cross-sectional area at the pre-formed fracture is one-third to two-thirds of the area of ​​the formed end face of the formed part.

4. A quick-change pin structure for a moving and fixed mold core according to claim 2, characterized in that: The drive unit is a polygonal blind hole formed on the free end of the mounting neck.

5. A quick-change pin structure for a moving and fixed mold core according to any one of claims 1 to 4, characterized in that: The pin also includes a light rod reinforcement part disposed between the forming part and the threaded fixing part, and the mold core is also provided with a light hole that is adapted to the light rod reinforcement part and coaxial with the threaded mounting hole.

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