A watch case injection mold

Abstract

This application discloses a watch case injection mold, comprising a front mold plate with a front mold core and a rear mold plate with a rear mold core. A sliding module is slidably mounted on the rear mold core. The front and rear mold cores cooperate to form a cavity for injection molding the product. The sliding module includes a main sliding block that slides laterally on the rear mold plate, an auxiliary sliding block that slides longitudinally on the rear mold plate, and an elongated molding insert. One end of the elongated molding insert is embedded and fixed inside the main sliding block, and the other end extends outward from the main sliding block. The elongated molding insert extends into the main sliding block to construct the bottom of the undercut groove and the side undercut inner wall. The auxiliary sliding block abuts against the extended end face of the elongated molding insert longitudinally and against the end face of the main sliding block laterally, together forming the outer wall structure of the product and the undercut groove on the outer wall. This application can significantly reduce the frictional resistance during demolding and core pulling, effectively reducing wear on the product and the mold.

Description

Technical Field

[0001] This application relates to the field of injection molding technology, and in particular to an injection mold for a watch case. Background Technology

[0002] Injection-molded products are common household items. Due to their advantages such as light weight, high strength, durability, and ease of assembly, they are widely used in home furnishings, medical equipment, building materials, and sporting goods. In the manufacturing process, molten plastic material is typically stirred evenly using a screw extruder at a specific temperature, then injected into an injection mold. The plastic material is formed within the mold cavity, and after cooling and solidification, the molded product is obtained. Finally, ejector pins push the molded product out of the mold.

[0003] Due to the complex structure of watch cases, there are many holes and grooves on the inner and outer sides and the top and bottom surfaces. In product design, watch cases are equipped with inverted grooves with a groove width smaller than the groove bottom width. For example, such grooves are provided on the two sides of the watch case where the watch strap is assembled. These grooves have a side inverted feature and cannot be directly demolded along the mold opening direction. The industry generally adopts an integral horizontal slide direct unidirectional core pulling molding structure.

[0004] Traditional molded parts consist of a single transverse slide that simultaneously forms the inner wall, bottom, and outer wall of the product's undercut groove. During demolding, the slide must maintain a large contact area with the inner wall of the groove and the outer wall of the watch case, sliding a long distance throughout the process. This results in a large sliding contact area and high frictional resistance. On the one hand, the newly formed plastic parts have low strength, making them prone to whitening, scratches, edge chipping, and warping of the product's shape, making it difficult to guarantee a high molding yield. On the other hand, the long-term large-area sliding friction between the slide and the product easily causes excessive wear on the slide's forming surface and the guide wear-resistant parts, increasing the mold clearance and leading to problems such as flash, dimensional deviations, shortened mold life, and high maintenance and repair costs. The traditional one-piece slide structure cannot separate the forming parts, making it impossible to pre-release the clamping constraint of the undercut groove. It can only rely on inclined guide pillars to drive the transverse forceful overall demolding, failing to structurally reduce the sliding stroke and frictional contact area. These technical defects have remained unresolved. Summary of the Invention

[0005] To address the problems in existing technologies where direct core pulling using an integral transverse slide mechanism results in a large sliding contact area, high frictional resistance, and is prone to causing product tearing and deformation, as well as severe wear of mold components. The watch case injection mold provided in this application adopts the following solution: A watch case injection mold, comprising: The front template has a front mold core. The rear template is provided with a rear mold core, and a sliding module is provided on the rear mold core; The front mold core and the rear mold core cooperate to form a cavity for injection molding of the product. The sliding module includes a main sliding block, an auxiliary sliding block, and a long strip molding insert. The main sliding block is slidably mounted on the rear mold plate, and the auxiliary sliding block is slidably mounted on the rear mold plate. One end of the long strip molding insert is embedded and fixed inside the main sliding block, and the other end of the long strip molding insert extends outward from the main sliding block. The long strip molding insert extends inward to construct the bottom of the undercut groove and the side undercut inner wall. When the mold is closed, the auxiliary sliding block abuts against the end face of the long strip molding insert extending outward along the longitudinal direction, and the auxiliary sliding block abuts against the end face of the main sliding block in the transverse direction, so that the auxiliary sliding block, the main sliding block, and the long strip molding insert surround each other to form the outer wall structure of the product and the undercut groove opened on the outer wall.

[0006] Optionally, the elongated molding insert has a longitudinal height dimension greater than that of the undercut groove, so that the elongated molding insert has a protruding abutment portion in the longitudinal direction of the undercut groove, and the outer end face of the abutment portion abuts and engages with the inner end face of the auxiliary sliding slider.

[0007] Optionally, the abutting part is a trapezoidal structure that gradually narrows away from the cavity, and the inner side of the auxiliary sliding block is formed with an abutting groove that matches the trapezoidal structure, and the abutting part and the abutting groove cooperate with each other.

[0008] Optionally, there are two main sliding blocks, which are symmetrically arranged at both ends of the cavity in the lateral direction; there are also two auxiliary sliding blocks, which are symmetrically arranged at both ends of the cavity in the longitudinal direction; the two main sliding blocks and the two auxiliary sliding blocks are all driven to slide through the mold opening and closing by inclined guide pillars, and the four of them abut against each other and surround each other to form undercut grooves on the outer walls at both ends of the product in the longitudinal direction.

[0009] Optionally, the main sliding block is provided with a contact surface for cooperating with the auxiliary sliding block. The contact surface is located on a vertical plane and is inclined towards the center of the cavity. A positioning space that gradually narrows towards the cavity is formed between the contact surfaces of the two main sliding blocks at both ends of the cavity. Correspondingly, the end of the auxiliary sliding block that faces the cavity gradually narrows and is adapted to fit the contact surface.

[0010] Optionally, there are two cavities arranged side by side in the horizontal direction; there is a sliding space between the two adjacent cavities for the main slide block to slide; a limiting screw is provided in the middle of the sliding space, and a limiting groove is correspondingly opened on the main slide block on both sides of the sliding space, and the limiting groove abuts and engages with the limiting screw when the mold is opened.

[0011] Optionally, it also includes an ejector plate located on the rear side of the rear mold plate, on which an inclined ejector pin is detachably installed. The inclined ejector pin passes through the rear mold plate and the rear mold core in sequence and extends into the cavity. The top of the inclined ejector pin forms part of the inner wall of the cavity.

[0012] Optionally, it also includes a hole-forming insert and a product ejector pin; the hole-forming insert slides vertically into the rear mold core and extends through into the cavity; the product ejector pin is vertically mounted on the ejector pin panel, and the hole-forming insert and the product ejector pin are located at the same end in the horizontal direction of the cavity; when the ejector pin panel rises vertically, the product ejector pin rises synchronously to eject the product inside the cavity.

[0013] Optionally, it also includes a return post, the lower end of which is fixed to the ejector plate and extends vertically upward through the rear template; a return spring is sleeved on the return post, and the return spring abuts between the ejector plate and the rear template.

[0014] Optionally, a return spring is provided between the main slide block and the rear mold core. The two ends of the return spring abut against the main slide block and the rear mold core, respectively. The return spring is used to drive the main slide block away from the rear mold core when the mold is opened.

[0015] In summary, this application includes at least one of the following beneficial technical effects: 1. The auxiliary sliding block can independently slide along the groove opening direction. During mold opening and demolding, the auxiliary sliding block first slides out along the groove opening direction, releasing the groove opening clamping constraint. Subsequently, the main sliding block only needs to slide slightly to detach from the outer wall of the product, shortening the sliding friction stroke of the main sliding block, reducing the sliding friction between the sliding block and the product during demolding, and avoiding scratches on the inner wall of the groove, product deformation, and wear on the sliding mechanism. This structure can reduce the frictional contact area and sliding stroke between the sliding block and the product during demolding, thereby reducing the risk of scratches and deformation of plastic parts, improving the molding yield of watch cases, reducing wear on mold components, extending mold life, and reducing later maintenance and mold repair costs. 2. The longitudinal height of the elongated molding insert is greater than that of the undercut groove, thus forming a protruding abutment. The outer end face of this abutment fits tightly against the inner end face of the auxiliary slide block. This design provides the elongated molding insert with an independent and stable longitudinal support and positioning point, preventing longitudinal displacement or vibration of the elongated molding insert due to injection pressure during injection molding. This achieves independent partitioning of the molding surface and the mating surface. The lower part of the elongated molding insert forms the undercut groove, while the upper longitudinal end face is specifically designed to abut against and limit the auxiliary slide block for sealing. The molding function and the positioning mating surface are separated, resulting in high mold closing accuracy and reducing the likelihood of flash or overflow during injection molding. Furthermore, the step-by-step demolding process does not interfere with each other, reducing friction and preventing damage. The insert is vertically higher than the slide groove, keeping the auxiliary slide block's contact position away from the glue area of ​​the undercut slide groove. When the mold opens, the auxiliary slide first demolds vertically, without scraping or rubbing against the inner wall of the slide groove. Then, the main slide pulls the core slightly laterally, structurally avoiding large-area sliding friction and effectively preventing the product from turning white or getting damaged. 3. The abutment portion is designed as a trapezoidal structure that gradually narrows away from the cavity. Correspondingly, the inner side of the auxiliary sliding block is formed with an abutment groove adapted to this trapezoidal structure. The inner contour of the abutment groove precisely matches the outer contour of the trapezoidal abutment portion, and its sidewalls also exhibit an inclination angle corresponding to the trapezoidal slope. This trapezoidal structure of the abutment portion forms a wedge-shaped body with a slope. This design allows the abutment portion to be guided into the abutment groove during mold closing, enabling smooth and precise insertion. On the other hand, since the auxiliary sliding block only needs to make a short stroke displacement during mold opening, the contact between the main sliding block and the auxiliary sliding block can be completely released without the abutment portion completely disengaging from the abutment groove. This shortens the stroke that generates sliding friction between the two and effectively reduces the sliding friction between the main sliding block and the auxiliary sliding block. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the overall functionality of an embodiment of this application; Figure 2 This is an exploded view of some components hidden in an embodiment of this application to show the row module; Figure 3 This is an embodiment of the present application. Figure 2 A magnified view of a section at point C; Figure 4 This is a schematic diagram illustrating the relationship between the product and the elongated molded insert in an embodiment of this application; Figure 5 This is a side view of an embodiment of this application, showing the mating relationship between the auxiliary sliding block and the elongated molding insert; Figure 6 This is an embodiment of the present application. Figure 1A cross-sectional schematic diagram of AA in the middle; Figure 7 The embodiments of this application are along Figure 1 A cross-sectional view of BB.

[0017] Explanation of reference numerals in the attached figures: 1. Front mold plate; 11. Front mold core; 12. First guide groove; 2. Rear mold plate; 21. Rear mold core; 22. Second guide groove; 3. Slide module; 31. Main slide slider; 311. Abutting surface; 312. Positioning space; 313. Limiting groove; 32. Auxiliary slide slider; 321. Abutting groove; 33. Long strip forming insert; 331. Abutting part; 34. Sliding space; 341. Limiting screw; 35. Return spring; 4. Ejector plate; 41. Angled ejector pin; 42. Hole-forming insert; 43. Product ejector pin; 44. Returning pin; 45. Return spring; 5. Ejector base plate; 51. Rear mold fixing plate; 52. Square iron; 53. Limiting pin; 54. Angled ejector seat. Detailed Implementation

[0018] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0020] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0021] The present application will be further described in detail below with reference to the accompanying drawings.

[0022] This application discloses an injection mold for a watch case.

[0023] Reference Figure 1 Traditional watch case injection molds, when molding inverted grooves with lateral inverted features, employ a single-piece lateral slide with direct unidirectional core pulling. This results in a large contact area between the slide and the product, and a long sliding stroke. Consequently, the molded plastic parts exhibit whitening, scratches, edge chipping, and warping deformation, making it difficult to guarantee a high molding yield. Simultaneously, wear on the slide molding surface and guide wear-resistant parts increases the mold clearance, leading to issues such as flash, dimensional deviations, shortened mold life, and increased maintenance costs.

[0024] Reference Figures 1 to 3 This embodiment provides a watch case injection mold, which includes a front mold plate 1 and a rear mold plate 2. The front mold plate 1 is provided with a front mold core 11, and the rear mold plate 2 is provided with a rear mold core 21. The front mold core 11 and the rear mold core 21 cooperate to form a cavity for injection molding the product. The sliding module 3 consists of a main sliding slider 31, an auxiliary sliding slider 32, and a long strip molding insert 33. The main sliding slider 31 is slidably mounted on the rear mold plate 2, and the auxiliary sliding slider 32 is slidably mounted on the rear mold plate 2. One end of the long strip molding insert 33 is embedded and fixed inside the main sliding slider 31, and the other end extends outward through the main sliding slider 31 and into the cavity to construct the bottom of the undercut groove and the side inner wall of the undercut groove. When the mold is closed, the auxiliary sliding block 32 abuts against the end face of the elongated molding insert 33 extending outside the main sliding block 31 along the longitudinal direction, and at the same time, the auxiliary sliding block 32 abuts against the end face of the main sliding block 31 in the transverse direction. Thus, the auxiliary sliding block 32, the main sliding block 31 and the elongated molding insert 33 surround each other and together form the outer wall structure of the product and the undercut groove opened on the outer wall.

[0025] Reference Figures 1 to 3For ease of understanding, the opening and closing direction between the front template 1 and the rear template 2 is defined as vertical, and the parting surface direction of the product is defined as horizontal. In the horizontal direction, there are mutually perpendicular horizontal and vertical directions. The sliding module 3 includes a main sliding slider 31, an auxiliary sliding slider 32, and a long strip forming insert 33. A first guide groove 12 is horizontally formed at the top of the rear template 2, and the main sliding slider 31 is slidably installed within this first guide groove 12 to ensure its horizontal movement. A second guide groove 22 is vertically formed at the top of the rear template 2, and the auxiliary sliding slider 32 is vertically slidably installed within the second guide groove 22 to ensure its vertical movement. One end of the long strip forming insert 33 is embedded and fixed inside the main sliding slider 31, and the other end extends outward through the main sliding slider 31 and into the cavity to construct the bottom of the undercut groove and the inner side wall of the undercut groove. In this embodiment, the elongated molding insert 33 is fixedly installed inside the main slide block 31 using an interference fit. The molding surface of the portion of the elongated molding insert 33 extending out of the main slide block 31 matches the shape of the undercut groove in the cavity to ensure the molding of the undercut groove. During mold closing, after the auxiliary slide block 32 moves into position longitudinally, its end face fits against the area of ​​the elongated molding insert 33. At the same time, the side surface of the auxiliary slide block 32 in the lateral direction contacts the side surface of the main slide block 31 in the lateral direction, so that the side surface of the auxiliary slide block 32 and the main slide block 31 fit tightly together.

[0026] This application decomposes the sliding module 3 into a horizontally sliding main sliding block 31, a vertically sliding auxiliary sliding block 32, and a long strip forming insert 33. These three components surround each other during mold closing, forming the outer wall structure of the product and the undercut groove. The auxiliary sliding block 32 can independently slide along the groove opening direction. During mold opening and demolding, the auxiliary sliding block 32 first slides out along the groove opening direction, releasing the groove opening constraint. Subsequently, the main sliding block 31 only needs to slide slightly to detach from the outer wall of the product, shortening the sliding friction stroke of the main sliding block and reducing the sliding friction between the sliding block and the product during demolding, thus avoiding scratches on the inner wall of the groove, product deformation, and wear on the sliding mechanism. This structure reduces the frictional contact area and sliding stroke between the sliding module 3 and the product during demolding, thereby reducing the risk of scratches and deformation of plastic parts, improving the molding yield of watch cases, reducing wear on mold components, extending mold life, and reducing subsequent maintenance and repair costs.

[0027] Considering that in the actual injection molding process, if the fit between the long strip molding insert 33 and the auxiliary sliding block 32 is not precise enough, or the fit in the longitudinal direction is not stable enough, it may cause the molding size deviation of the undercut groove, or even defects such as flash or under-filling.

[0028] Reference Figures 3 to 4Therefore, this application further proposes that the longitudinal height dimension of the elongated molding insert 33 is greater than the longitudinal height dimension of the undercut groove, so that the elongated molding insert 33 has an abutment portion 331 protruding from the undercut groove in the longitudinal direction, and the outer end face of the abutment portion 331 abuts and cooperates with the inner end face of the auxiliary sliding slider 32.

[0029] Specifically, the elongated molding insert 33 has a greater longitudinal height than the undercut groove, ensuring that the elongated molding insert 33 has an extension in the longitudinal direction exceeding the required molding height of the undercut groove. This design allows the elongated molding insert 33 to provide an additional, independent abutment surface, rather than relying solely on a single longitudinal surface of the elongated molding insert 33 to engage with the auxiliary slide block 32. Through this design, the abutment portion 331 protruding from the undercut groove directly contacts the auxiliary slide block 32 for abutment and limiting. This ensures stable longitudinal support for the elongated molding insert 33 during injection molding, preventing displacement or deformation due to injection pressure. In the mold-closed state, the inner end face of the auxiliary slide block 32 tightly fits against the outer end face of the abutment portion 331 of the elongated molding insert 33. This abutment engagement is a close surface-to-surface contact, achieving good sealing and precise positioning. In actual working conditions, these contact surfaces undergo fine grinding and polishing to reduce friction and improve fit accuracy, which will not be elaborated here.

[0030] Through the above technical solution, the longitudinal height of the elongated molding insert 33 is greater than the longitudinal height of the undercut groove, thus forming a protruding abutment part 331. The outer end face of this abutment part 331 is in close contact with the inner end face of the auxiliary sliding block 32. This design provides the elongated molding insert 33 with an independent and stable longitudinal support and positioning point, avoiding longitudinal displacement or vibration of the elongated molding insert 33 due to injection pressure during the injection molding process. Thus, the molding surface and the mating surface are separated, with the undercut groove formed at the bottom of the elongated molding insert 33, and the upper longitudinal end face specifically abutting and limiting the auxiliary sliding block 32 for sealing. The molding function and the positioning mating surface are separated, resulting in high mold closing accuracy and reducing the likelihood of flash or overflow during injection molding. Furthermore, the step-by-step demolding does not interfere with each other, reducing friction and preventing damage. The insert is vertically higher than the slide groove, so that the auxiliary slide slider 32 abuts away from the glue area of ​​the undercut slide groove. When the mold is opened, the auxiliary slide will first demold vertically, without scraping or rubbing against the inner wall of the slide groove. Then the main slide will pull the core slightly laterally, which avoids large-area sliding friction from the structure and effectively prevents the product from turning white or being damaged.

[0031] In some embodiments described above, the abutment portion 331 of the elongated insert 33 has a protruding abutment portion 331 in the longitudinal direction, which abuts against the inner end face of the auxiliary sliding block 32. However, in the actual injection molding process, the frictional force generated in the longitudinal direction between the auxiliary sliding block 32 and the abutment portion 331 during mold opening and closing is also noteworthy.

[0032] Reference Figures 4 to 5 In this regard, this application further proposes that the abutting part 331 is a trapezoidal structure that gradually narrows in the direction away from the cavity, and the inner side of the auxiliary sliding slider 32 is formed with an abutting groove 321 that is adapted to the trapezoidal structure. The abutting part 331 and the abutting groove 321 cooperate with each other, so that the abutting part 331 abuts and cooperates with multiple inner end faces of the auxiliary sliding slider 32.

[0033] Specifically, the abutment portion 331 is designed as a trapezoidal structure that gradually narrows away from the cavity. Correspondingly, the inner side of the auxiliary sliding block 32 is formed with an abutment groove 321 that matches the trapezoidal structure. The inner contour of the abutment groove 321 precisely matches the outer contour of the trapezoidal abutment portion 331, and its sidewalls also exhibit an inclination angle corresponding to the trapezoidal slope. This trapezoidal structure of the abutment portion 331 forms a wedge-shaped body with an inclined surface. This design allows the abutment portion 331 to be guided into the abutment groove 321 during mold closing, achieving smooth and precise insertion. On the other hand, during mold opening, the auxiliary sliding block 32 only needs to make a short stroke displacement to completely release the contact between the main sliding block 31 and the auxiliary sliding block 32, without requiring the abutment portion 331 to completely disengage from the abutment groove 321. This shortens the stroke that generates sliding friction between the two and effectively reduces the sliding friction between the main sliding block 31 and the auxiliary sliding block 32.

[0034] In actual production, many watch cases require multiple, especially symmetrically arranged, undercut grooves to be formed on their outer walls to meet functional or aesthetic design requirements. Using only a single row module 3 would make it difficult to efficiently and accurately achieve the simultaneous forming of multiple undercut grooves, potentially leading to a more complex mold structure or lower production efficiency.

[0035] In this regard, this application further proposes that there are two main sliding blocks 31, which are symmetrically arranged at both ends of the cavity in the transverse direction; there are also two auxiliary sliding blocks 32, which are symmetrically arranged at both ends of the cavity in the longitudinal direction; the two main sliding blocks 31 and the two auxiliary sliding blocks 32 are all driven to slide through the mold opening and closing by inclined guide pillars, and the four of them abut against each other and surround each other to form undercut grooves on the outer walls of both ends of the product in the longitudinal direction.

[0036] Specifically, there are two main sliding block sliders 31, which are slidably mounted on the rear template 2 for lateral sliding. They move towards the center of the cavity when the mold is closed and away from the cavity when the mold is opened, thus completing the forming of the product's lateral sidewalls. The symmetrical arrangement ensures the uniformity and balance of the product's two-sided structure. Simultaneously, there are also two auxiliary sliding block sliders 32, which are similarly slidably mounted on the rear template 2 for moving towards the center of the cavity when the mold is closed and away from the cavity when the mold is opened. The inclined guide pillar is a driving mechanism that converts the mold's opening and closing motion into the lateral sliding of the sliding block. Its core function is to ensure that the sliding block can smoothly disengage from the product's undercut structure when the mold is opened and accurately reset when the mold is closed. Specifically, the mold is also equipped with inclined guide pillars, which are arranged at an angle. The upper end of the inclined guide pillars can be slidably inserted into the front mold plate 1 and extends obliquely downward from the front mold plate 1 into the rear mold plate 2. The inclined guide pillars vertically penetrate the main slide block 31 along their own inclined direction and form a sliding guide engagement with the main slide block 31. When the mold performs vertical opening and closing actions, the front mold plate 1 and the rear mold plate 2 generate relative vertical displacement. Utilizing the guiding effect of the inclined slope of the inclined guide pillars, the vertical opening and closing motion of the mold is converted into the horizontal sliding motion of the main slide block 31, thereby realizing the core pulling and retraction and mold closing reset actions of the main slide block 31.

[0037] In the mold-closed state, these four sliding blocks (i.e., two main sliding blocks 31 and two auxiliary sliding blocks 32) abut against each other and cooperate to form the complex shape of the outer wall of the product, and form undercut grooves on the outer walls at both ends of the product's longitudinal direction. When the mold opens, the inclined guide pillars drive the sliding blocks to slide outward, first disengaging from the horizontal undercut structure, and then the mold opens completely, allowing the product to be ejected smoothly.

[0038] By employing the aforementioned technical solution, the number of main sliding block 31 and auxiliary sliding block 32 is increased to two each, and they are symmetrically arranged at both ends of the cavity in the horizontal and vertical directions. All are driven to slide by inclined guide pillars, allowing the mold to simultaneously form undercut grooves on the outer walls of both longitudinal ends of the product. The four sliding blocks mutually enclose and limit each other, forming a comprehensive constraint on the watch case cavity, which can counteract the extrusion force of the high-pressure molten material during injection, preventing swelling, warping, and deformation of thin-walled parts of the watch case and the undercut grooves. The introduction of inclined guide pillars ensures precise and reliable driving of the sliding blocks during mold opening and closing, avoiding positioning errors and operational inconveniences caused by manual or complex mechanical structures, thereby guaranteeing the forming accuracy and quality of the undercut grooves on the product.

[0039] Reference Figures 1 to 3Considering that although the above-mentioned solutions in this application embodiment alleviate the friction between the main sliding block 31 and the outer wall of the product to a certain extent, and reduce the friction between the elongated molding insert 33 and the auxiliary sliding block 32, in actual working conditions, there is still a certain amount of sliding friction at the contact point between the auxiliary sliding block 32 and the main sliding block 31 during mold opening and closing. Therefore, this application further proposes that the main sliding block 31 is provided with a contact surface 311 for cooperating with the auxiliary sliding block 32. The contact surface 311 is located on a vertical plane and is inclined towards the center of the cavity. As the contact surface 311 approaches the cavity, it gradually gets closer to the center of the cavity. A positioning space 312 that gradually narrows towards the cavity is formed between the contact surfaces 311 of the two main sliding blocks 31 at both ends of the cavity. Correspondingly, the end of the auxiliary sliding block 32 facing the cavity gradually narrows and adapts to and fits the contact surface 311. Specifically, one end of the elongated insert 33 is fixedly installed inside the main sliding block 31, and the other end passes through the abutment surface 311 in the horizontal direction to the outside of the main sliding block 31.

[0040] Reference Figures 1 to 3 The contact surface 311 on the main slide block 31 is a key surface for contact and force transmission between the main slide block 31 and the auxiliary slide block 32 in the mold-closed state. This contact surface 311 is designed to ensure that the two slide blocks fit tightly together, forming a closed cavity wall and effectively withstanding the pressure generated during injection molding. The contact surface 311 is located on a vertical plane and is inclined towards the center of the cavity, with its main direction perpendicular to the mold parting surface and inclined towards the central area of ​​the cavity. The two main slide blocks 31 at both ends of each cavity are correspondingly arranged, and their respective contact surfaces 311 together form a positioning space 312 that gradually narrows towards the cavity, exhibiting a frustum structure. Correspondingly, the end of the auxiliary slide block 32 facing the cavity is designed to taper to fit and conform to the contact surface 311 on the main slide block 31. This tapered structure forms a complementary mating surface with the inclined contact surface 311 on the main slide block 31, ensuring a tight fit during mold closing and effectively eliminating gaps. On one hand, this inclined arrangement guides the auxiliary slide block 32 during mold closing, ensuring it accurately enters its predetermined position and providing a wedge-like self-locking effect, thereby enhancing the tightness and stability of the fit. More importantly, because the positioning space 312 gradually expands away from the cavity, the auxiliary slide block 32 only needs to make a short displacement during mold opening to completely release the contact between the main slide block 31 and the auxiliary slide block 32. This eliminates the need for the end of the auxiliary slide module 3 to completely disengage from the positioning space 312, thus shortening the stroke that generates sliding friction and effectively reducing the sliding friction between the main slide block 31 and the auxiliary slide block 32.

[0041] Through the above technical solution, an abutment surface 311 is provided on the main slide block 31, which is inclined towards the center of the cavity, and a positioning space 312 that gradually narrows towards the cavity is formed between the abutment surfaces 311 of the two main slide blocks 31 at both ends of the cavity. At the same time, the end of the auxiliary slide block 32 also gradually narrows to fit and conform to the abutment surface 311. This application achieves a high-precision self-centering effect between the main slide block 31 and the auxiliary slide block 32, and can effectively reduce the sliding friction between the main slide block 31 and the auxiliary slide block 32 when the mold is opened, thereby reducing the wear of the mold.

[0042] In actual production, in order to improve production efficiency, it is often necessary to mold multiple products simultaneously. When the mold is designed with a multi-cavity structure, how to effectively arrange multiple cavities and ensure that the main slide blocks 31 can avoid mutual interference or inaccurate positioning during the mold opening process is a technical problem that needs to be solved.

[0043] In response, this application further proposes an injection mold for a watch case, wherein there are two cavities arranged side by side in a horizontal direction; there is a sliding space 34 between the two adjacent cavities for the main sliding block 31 to slide; a limiting screw 341 is provided in the middle of the sliding space 34, and a limiting groove 313 is correspondingly provided on the main sliding block 31 on both sides of the sliding space 34, and the limiting groove 313 abuts against the limiting screw 341 when the mold is opened.

[0044] Specifically, each front mold plate 1 has two front mold cores 11 installed on its rear side, and correspondingly, each rear mold plate 2 has two front mold cores 11 installed on its front side. The front mold cores 11 and rear mold cores 21 are arranged one-to-one and can form part of the cavity when the mold is closed. For ease of description, each front mold core 11 and its corresponding rear mold core 21 are defined as a set of mold core modules, and the two sets of mold core modules are arranged side by side laterally. This dual-cavity design aims to produce two watch case products simultaneously in one injection molding cycle, thereby significantly improving production efficiency. To ensure that each main slide block 31 can operate smoothly in the multi-cavity structure, a sliding space 34 is reserved between two adjacent cavities for the main slide block 31 to slide. This ensures that when the mold is opened, the main slide block 31 of each of the two cavities can slide freely to the outside or inside to complete the demolding action, and will not collide with the other main slide block 31 of the adjacent cavity.

[0045] Reference Figures 3 to 5Based on this, in order to precisely control the mold opening stroke and final position of the main sliding block 31, a limiting screw 341 is provided in the middle of the sliding space 34. One end of the limiting screw 341 is fixed to the rear template 2, and the other end extends into the sliding space 34, with the head of its protruding part having a cylindrical structure. At the same time, limiting grooves 313 are correspondingly opened on the main sliding blocks 31 on both sides of the sliding space 34. Each limiting groove 313 is semi-cylindrical, and its shape and size match the head of the limiting screw 341, so that when the mold opens, the two limiting grooves 313 can surround and abut against the limiting screw 341. This abutting fit will precisely prevent the main sliding block 31 from continuing to slide, thereby positioning it in the preset mold opening position.

[0046] By using the above technical solution, setting the number of cavities to two and arranging them horizontally side by side significantly improves production efficiency. The sliding space 34 set between adjacent cavities ensures that the two main slide blocks 31 can slide independently and smoothly during mold opening, avoiding mutual interference. Furthermore, by setting a limiting screw 341 in the middle of the sliding space 34, and having the limiting groove 313 on the main slide block 31 abut against the limiting screw 341 during mold opening, the mold opening stroke and final position of the main slide block 31 can be precisely controlled. This effectively solves the problem of positioning accuracy and stability of the main slide block 31 in multi-cavity molds, avoiding excessive sliding or inaccurate positioning, thereby ensuring the consistency of product molding quality.

[0047] In some of the embodiments described above in this application, although the sliding module 3, composed of the main sliding slider 31, the auxiliary sliding slider 32, and the elongated molding insert 33, can effectively solve the molding and demolding problems of the undercut groove on the outer wall of the product, for products with complex internal structures or internal undercuts, such as watch cases, the molding and demolding of the cavity may still face challenges. If only conventional straight ejector pins are used for ejection, the internal structure of the product may be damaged or demolding may not be successful, especially when a specific inner wall shape or internal undercut is required.

[0048] Reference Figures 5 to 6 In this regard, this application further proposes that it also includes an ejector plate 4 located on the rear side of the rear mold plate 2, on which an inclined ejector post 41 is detachably installed. The inclined ejector post 41 passes through the rear mold plate 2 and the rear mold core 21 in sequence and extends into the cavity. The top of the inclined ejector post 41 forms part of the inner wall of the cavity.

[0049] Specifically, the ejector plate 4 is a plate in the injection mold used to install and drive the ejection mechanism (such as ejector pins, angled ejectors, etc.). It is located behind the rear platen 2 and is linked to the opening and closing action of the mold through the ejection mechanism to realize the ejection of the product. The ejector plate 4 provides a stable mounting platform, transmits the driving force of the ejection system to the ejection element, thereby pushing the molded product out of the cavity. After the mold opens, the ejector plate 4 moves vertically towards the cavity under the drive of the mechanical ejector rod (not shown in the figure), driving the ejection element to push the product out.

[0050] The main body of the angled ejector pin 41 is inclined at a certain angle, and its top is designed according to the shape of the product's inner wall. It is used to form undercuts, holes, or special shapes inside the product and to provide an angled ejection force during demolding. The angled ejector pin 41 is used to solve the demolding problem of undercuts or complex inner wall structures inside the product. Through its inclined movement trajectory, it can move a certain distance inward to disengage from the undercut part before ejecting upward, avoiding product damage. At the same time, its top directly participates in the forming of the cavity, ensuring the precise shape of the product's inner wall. The angled ejector pin passes through the ejector plate 4, the rear mold plate 2, and the rear mold core 21. Its inclined part mates with the angled hole on the rear mold core 21 and slides along the direction of the angled hole under the drive of the ejector plate 4.

[0051] Behind the ejector plate 4, an ejector base plate 5 and a rear mold fixing plate 51 are arranged in sequence. Two square iron blocks 52 are vertically arranged side-by-side on the rear mold fixing plate 51, forming a movable space between them. The ejector plate 4 and the ejector base plate 5 are fixedly connected and can be driven to vertically rise and fall together within this movable space. A limit pin 53 is vertically fixed on the ejector base plate 5. A slanted ejector seat 54 is inserted into the limit pin 53. The bottom of the slanted ejector seat 54 is inserted into the limit pin 53, and the top of the slanted ejector seat 54 extends above the ejector plate 4. The bottom of the slanted ejector post 41 is detachably slidably installed on the top of the slanted ejector seat 54. The slanted ejector post 41 and the ejector plate 4 are detachably installed, meaning that the connection method allows for convenient installation, disassembly, or replacement without disassembling the main mold structure. This detachable installation design improves the mold's maintenance convenience, production efficiency, and flexibility. When the inclined ejector pin 41 is worn, damaged, or needs to be replaced with an inclined ejector pin 41 of a different specification to suit different products, the inclined ejector pin 41 and the inclined ejector seat 54 can be easily replaced.

[0052] During the demolding process, the ejector plate 4 drives the inclined ejector pin 41 to move along its inclined direction, allowing the top of the inclined ejector pin 41 to smoothly disengage from the undercuts or complex structures inside the product while ejecting it, avoiding the mold jamming or product damage that may be caused by traditional straight ejector pins. Furthermore, the detachable installation design of the inclined ejector pin 41 greatly improves the convenience of mold maintenance. When the inclined ejector pin 41 needs to be replaced due to wear or product design changes, there is no need for large-scale mold disassembly, thereby shortening mold downtime and improving production efficiency and mold adaptability.

[0053] This application further proposes that the watch case injection mold also includes a hole-forming pin 42 and a product ejector pin 43. The hole-forming pin 42 slides vertically into the rear mold core 21 and extends through into the cavity. The product ejector pin 43 is vertically mounted on the ejector plate 4, and the hole-forming pin 42 and the product ejector pin 43 are located at the same end in the horizontal direction. When the ejector plate 4 rises vertically, the product ejector pin 43 rises synchronously to eject the product from the cavity.

[0054] Specifically, the hole-forming insert 42 is an elongated component used to form precise holes or through holes in injection-molded products. During the injection molding process, the hole-forming insert 42 extends into the cavity, becoming part of the cavity, to form the desired hole structure on the product. It slides vertically into the rear mold core 21 and extends through the cavity. The hole-forming insert 42 can be precisely positioned when the mold is closed and can be smoothly withdrawn when the mold is opened and demolded, avoiding damage to the product. The product ejector pin 43 is mounted on the ejector plate 4 and achieves the ejection function through the movement of the ejector plate 4. The ejection end face of the product ejector pin 43 is used to contact the product surface and apply a pushing force to the product during the ejection process.

[0055] The hole-forming insert 42 and the product ejector pin 43 are located at the same end in the horizontal direction of the cavity. This configuration ensures that the side of the product with the hole structure has both hole forming and product ejection functions. When the ejector plate 4 rises vertically, the product ejector pin 43 will rise synchronously because it is vertically mounted on the ejector plate 4. This synchronous rising motion mode ensures that the product can receive timely and effective ejection support near the hole area formed by the hole-forming insert 42 during demolding, avoiding local sticking or deformation of the product due to the complex hole structure during demolding.

[0056] In the actual injection molding process, after the ejector plate 4 completes the ejection action, how to ensure that it can accurately and reliably return to the initial position, so as to avoid affecting the subsequent mold closing operation and product molding quality due to incomplete or inaccurate return, is a technical problem that needs to be solved.

[0057] In this application, the watch case injection mold further includes a return post 44, the lower end of which is fixed to the ejector plate 4 and extends vertically upward through the rear template 2. A return spring 45 is fitted on the return post 44, and the return spring 45 abuts against the ejector plate 4 and the rear template 2. The return post 44, as a guide component, primarily provides a stable linear motion trajectory for the ejector plate 4, ensuring that the ejector plate 4 can move smoothly along a preset vertical direction during ejection and return. The return spring 45 is fitted on the return post 44, with its two ends abutting against the ejector plate 4 and the rear template 2 respectively. When the ejector plate 4 moves forward during ejection, the return spring 45 is compressed and stores elastic potential energy. After ejection is completed, the return spring 45 releases its stored energy, generating a continuous restoring force, actively pushing the ejector plate 4 backward to return it completely to its initial closed position. This is crucial for ensuring that the angled ejector pin 41 completely exits the cavity before mold closing, avoiding damage to the mold or product, thereby improving the stability of mold operation and the molding quality of the product, and extending the service life of the mold.

[0058] In some embodiments of this application, after the watch case injection mold completes injection molding, the main slide block 31 needs to be reliably disengaged from the cavity to avoid damage to the molded product and ensure smooth demolding. However, in actual operation, the main slide block 31 may cause poor demolding or reduced efficiency when the mold structure is complex or there is a certain amount of friction.

[0059] In this regard, this application further proposes that a return spring 35 is provided between the main slide block 31 and the rear mold core 21. The two ends of the return spring 35 abut against the main slide block 31 and the rear mold core 21 respectively. The return spring 35 is used to drive the main slide block 31 away from the rear mold core 21 when the mold is opened.

[0060] In this embodiment, the return spring 35 is a helical compression spring made of high-strength spring steel or similar materials. Specifically, the return spring 35 is arranged in the space between the main slide block 31 and the rear mold core 21. A first blind hole for accommodating one end of the return spring 35 is provided at each of the two ends of the rear mold core 21 in the horizontal direction, and a corresponding second blind hole for accommodating the other end of the return spring 35 is provided on the main slide block 31. The return spring 35 is installed in the first and second blind holes respectively at its two ends in the horizontal direction to ensure that the spring can stably drive the relative movement of the rear mold core 21 and the main slide block 31 during compression and release.

[0061] This contact method ensures that the return spring 35 can effectively transmit force between the main slide block 31 and the rear mold core 21. When the mold closes, the main slide block 31 enters the cavity under the action of the mold closing force, simultaneously compressing the return spring 35 to store energy. When the mold opens, the mold closing force is released, the elastic potential energy of the return spring 35 is released, thereby pushing the main slide block 31 to move away from the rear mold core 21 until it abuts against the limit screw 341. This effectively solves the problem of poor disengagement or jamming of the main slide block 31 during mold opening, ensuring that the main slide block 31 can separate from the product in a timely and smooth manner, thus avoiding damage to the product. At the same time, the spring continuously applies preload force, which can eliminate the sliding clearance, suppress the shifting deviation during the working process, and ensure the forming accuracy of the undercut groove of the product.

[0062] When the mold is closed, the auxiliary sliding block 32 abuts against the extended end face of the elongated molding insert 33 along the longitudinal direction. At the same time, the auxiliary sliding block 32 abuts against the end face of the main sliding block 31 in the transverse direction. Through this engagement, the auxiliary sliding block 32, the main sliding block 31, and the elongated molding insert 33 surround each other to form the outer wall structure of the product and the undercut groove on the outer wall.

[0063] In summary, during the mold opening and demolding process, the auxiliary sliding block 32 slides longitudinally and disengages from the abutment portion 331 of the elongated molding insert 33. This longitudinal separation action pre-releases the clamping constraint of the outer wall of the undercut groove on the outer wall of the product. Compared with the traditional one-piece sliding structure, this step-by-step disengagement avoids excessive tensile stress in the undercut area, significantly reducing the risk of scratches, whitening, or edge chipping on the outer wall of the product.

[0064] Subsequently, driven by the return spring 35, the main slide block 31 slides laterally away from the rear mold core 21. Since the elongated molding insert 33 is fixed inside the main slide block 31, it is pulled out laterally along with the main slide block 31, thereby separating the bottom of the undercut groove and the inner side wall of the undercut groove from the product. At this time, the elongated molding insert 33 only contacts the inner wall of the undercut groove, and its sliding contact area is much smaller than the total contact area between the traditional one-piece slide block and the outer wall of the product and the inner side wall of the undercut groove during demolding. This reduction in contact area significantly reduces sliding friction resistance, further protecting the integrity of the newly formed product and extending the service life of the slide block forming surface and the guide wear-resistant parts.

[0065] Through the aforementioned structure and working principle, this mold decomposes the undercut groove forming slide module 3 into a main slide slider 31, an auxiliary slide slider 32, and a long strip forming insert 33, all capable of independent longitudinal and lateral movement. This enables pre-release of the undercut area and step-by-step demolding. This design effectively solves the problems of plastic part damage, mold wear, and low yield caused by large-area sliding friction during demolding in traditional one-piece slides, thereby improving product molding quality and mold lifespan.

[0066] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A watch case injection mold, characterized in that, include: The front template (1) is provided with a front mold core (11); The rear template (2) is provided with a rear mold core (21), and a sliding module (3) is provided on the rear mold core (21); The front mold core (11) and the rear mold core (21) cooperate to form a cavity for injection molding products. The sliding module (3) includes a main sliding block (31), an auxiliary sliding block (32), and a long strip molding insert (33). The main sliding block (31) is slidably mounted on the rear mold plate (2), and the auxiliary sliding block (32) is slidably mounted on the rear mold plate (2). One end of the long strip molding insert (33) is embedded and fixed inside the main sliding block (31), and the other end of the long strip molding insert (33) extends outward from the main sliding block (31). The sliding block (31) is inserted into the elongated molding insert (33) to form the bottom of the undercut groove and the side undercut inner wall. When the mold is closed, the auxiliary sliding block (32) abuts against the end face of the elongated molding insert (33) extending outward along the longitudinal direction, and the auxiliary sliding block (32) abuts against the end face of the main sliding block (31) in the transverse direction, so that the auxiliary sliding block (32), the main sliding block (31) and the elongated molding insert (33) surround each other and jointly form the outer wall structure of the product and the undercut groove opened on the outer wall.

2. The watch case injection mold according to claim 1, characterized in that, The elongated molding insert (33) has a longitudinal height dimension greater than that of the undercut groove, so that the elongated molding insert (33) has a protruding abutment portion (331) in the longitudinal direction of the undercut groove, and the outer end face of the abutment portion (331) abuts and engages with the inner end face of the auxiliary sliding block (32).

3. The watch case injection mold according to claim 2, characterized in that, The abutting part (331) is a trapezoidal structure that gradually narrows away from the cavity. The inner side of the auxiliary sliding block (32) is formed with an abutting groove (321) that is adapted to the trapezoidal structure. The abutting part (331) and the abutting groove (321) cooperate with each other.

4. The watch case injection mold according to claim 1, characterized in that, Two main sliding blocks (31) are provided, which are symmetrically arranged at both ends of the cavity in the horizontal direction; two auxiliary sliding blocks (32) are also provided, which are symmetrically arranged at both ends of the cavity in the vertical direction; the two main sliding blocks (31) and the two auxiliary sliding blocks (32) are all driven to slide through the opening and closing of the mold by the inclined guide post, and the four of them abut against each other and surround each other to form undercut grooves on the outer walls of both ends of the product in the vertical direction.

5. The watch case injection mold according to claim 1, characterized in that, The main sliding block (31) is provided with a contact surface (311) for cooperating with the auxiliary sliding block (32). The contact surface (311) is located on a vertical plane and is inclined towards the center of the cavity. The contact surfaces (311) of the two main sliding blocks (31) at both ends of the cavity form a positioning space (312) that gradually narrows towards the cavity. Correspondingly, the auxiliary sliding block (32) gradually narrows towards the end of the cavity and is adapted to fit the contact surface (311).

6. The watch case injection mold according to claim 1, characterized in that, There are two cavities arranged side by side in the horizontal direction; there is a sliding space (34) between the two adjacent cavities for the main slide block (31) to slide; a limiting screw (341) is provided in the middle of the sliding space (34), and a limiting groove (313) is correspondingly opened on the main slide block (31) on both sides of the sliding space (34). When the mold is opened, the limiting groove (313) abuts against the limiting screw (341).

7. The watch case injection mold according to claim 1, characterized in that, It also includes an ejector plate (4) located on the rear side of the rear template (2), on which a detachable slanted ejector pin (41) is installed. The slanted ejector pin (41) passes through the rear template (2) and the rear mold core (21) in sequence and extends into the cavity. The top of the slanted ejector pin (41) forms part of the inner wall of the cavity.

8. The watch case injection mold according to claim 7, characterized in that, It also includes a hole-forming insert (55)(42) and a product ejector pin (43); the hole-forming insert (55)(42) slides vertically into the rear mold core (21) and extends through into the cavity; the product ejector pin (43) is vertically mounted on the ejector plate (4), and the hole-forming insert (55)(42) and the product ejector pin (43) are located at the same end in the horizontal direction of the cavity; when the ejector plate (4) rises vertically, the product ejector pin (43) rises synchronously to eject the product inside the cavity.

9. A watch case injection mold according to claim 7, characterized in that, It also includes a return post (44), the lower end of which is fixed to the ejector panel (4) and extends vertically upward through the rear template (2); a return spring (45) is sleeved on the return post (44), and the return spring (45) abuts between the ejector panel (4) and the rear template (2).

10. A watch case injection mold according to claim 1, characterized in that, A return spring (35) is provided between the main slide block (31) and the rear mold core (21). The two ends of the return spring (35) abut against the main slide block (31) and the rear mold core (21) respectively. The return spring (35) is used to drive the main slide block (31) away from the rear mold core (21) when the mold is opened.

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