Injection mold, production method of safety helmet shell and safety helmet

Abstract

The invention is suitable for the technical field of safety helmets, and provides an injection mold, a production method of a safety helmet shell and a safety helmet, the injection mold is used for producing the safety helmet shell, the injection mold comprises a fixed mold half mold, a fixed mold half mold, a fixed mold half mold and a movable mold half mold, the fixed mold half mold comprises a male mold core for limiting the inner surface contour of the safety helmet shell; the movable mold half mold comprises a concave mold cavity for limiting the outline of the outer surface of the safety helmet shell, and the concave mold cavity and the convex mold core jointly form a mold cavity when the injection mold is closed; a glue outlet of the glue feeding system is formed in the surface of the male mold core of the fixed mold half mold and is used for introducing molten plastic into the mold cavity; a movable structure of the ejection mechanism can move relative to the fixed mold half mold, and the ejection mechanism is configured to eject the safety helmet shell formed on the male mold core out of the fixed mold half mold after the movable mold half mold is separated from the fixed mold half mold. The production line solves the problem that appearance defects exist in production of existing safety helmet shells.

Description

Technical Field

[0001] The present invention relates to the technical field of safety helmets, and particularly relates to an injection mold, a production method of a safety helmet shell, and a safety helmet. Background Art

[0002] A safety helmet is an important personal protective equipment in industrial production, construction and other fields to protect workers' heads from falling objects, impacts, etc. The impact resistance of a safety helmet is directly related to the life safety of the wearer, so it is crucial.

[0003] Currently, the common safety helmet shells on the market are usually manufactured by injection molding process. Its mold is mainly composed of a fixed mold (female mold) and a movable mold (male mold). During the injection process, the molten plastic is injected into the mold cavity through the gate point at the top of the fixed mold, and after cooling and solidifying, a shell structure is formed. The fixed mold corresponds to the outer surface of the shell, and the movable mold corresponds to the inner surface of the shell. After injection molding, the movable mold moves with the formed shell, and the shell is ejected from the movable mold by means of ejector pins or ejector rods. There will be plastic sprues remaining at the gate point, which usually need to be trimmed later.

[0004] However, the existing safety helmet injection molding process has the following inherent defects, which will affect the impact resistance of the safety helmet, especially in specific areas:

[0005] Sprue mark problem: To ensure the appearance of the safety helmet, the gate point is usually set at the top of the outer surface of the safety helmet shell (i.e., on the fixed mold side). This results in the sprue mark (gate residue) appearing directly above the safety helmet, which is exactly the part that is most vulnerable to falling object impacts during operation. At the same time, the sprue mark formed on the outer surface of the shell affects the appearance. To ensure the appearance of the shell, additional processes (such as shearing or grinding) are required to process the remaining sprue, resulting in an increase in production costs; at the same time, due to insufficient material compensation in the sprue area, it is prone to become a mechanical weak point.

[0006] Concentration of structural weak areas problem: The weld line area at the end of the molten plastic flow path, the gate point, and the plastic cooling shrinkage area on the opposite side of the gate point are prone to form material strength weak points. These weak areas (especially the outer surface and the corresponding inner surface positions at the top of the head) have significantly reduced anti-penetration and energy absorption capabilities when the worker's head is impacted, posing a safety hazard.

[0007] Difficulty in balancing design contradictions problem: In the existing process, to avoid the sprue mark being exposed, the gate point needs to be set on the outer surface of the shell for subsequent grinding, but this results in the mechanical weak area being directly located in the key protection area at the top. If the gate position is adjusted to optimize the strength distribution, it will increase the demolding difficulty or manufacturing complexity due to structural conflicts.

[0008] Although existing technologies improve strength by reinforcing materials (such as adding glass fiber) or increasing wall thickness, their effectiveness is limited and may lead to increased weight or reduced stability of the injection molding process. Therefore, an innovative injection molding solution is urgently needed that can eliminate the water mark on the outer surface and optimize the distribution of weak areas of the material, thereby improving the overall protective performance of the helmet. Summary of the invention

[0009] Based on this, the purpose of the present invention is to provide an injection mold, a method for producing a helmet shell, and a helmet, so as to fundamentally solve the problem of appearance defects existing in the production of existing helmet shells.

[0010] An injection mold according to an embodiment of the present invention is used to produce a helmet shell, and the injection mold comprises:

[0011] A fixed mold half, comprising a male mold core for defining the inner surface contour of the helmet shell;

[0012] The movable mold half comprises a concave mold cavity for defining the outer surface contour of the helmet shell, wherein the concave mold cavity and the convex mold core jointly form a mold cavity when the injection mold is closed;

[0013] A glue feeding system, wherein the glue outlet of the glue feeding system is arranged on the surface of the male core of the fixed mold half, and is used to introduce molten plastic into the mold cavity;

[0014] and an ejection mechanism, wherein the movable structure of the ejection mechanism can move relative to the fixed mold half and is configured to eject the helmet shell formed on the punch core from the fixed mold half after the movable mold half is separated from the fixed mold half.

[0015] In addition, an injection mold according to the above embodiment of the present invention may also have the following additional technical features:

[0016] Furthermore, the ejection mechanism comprises:

[0017] A driving component fixedly mounted on the outside of the fixed mold half;

[0018] A moving component that is drivingly connected to the driving component and can reciprocate along the opening and closing direction of the injection mold under the drive of the driving component;

[0019] and at least one inclined roof mounted on said moving member;

[0020] A notch matching the inclined top is provided on the core of the punch of the fixed mold half; when the injection mold is closed and the movable part is in the initial position, the top surface of the inclined top is embedded in the notch and is flush with the surface of the punch core, together forming a contour that defines the inner surface of the helmet shell.

[0021] Furthermore, the injection mold further includes two enclosing mechanisms, and the two enclosing mechanisms are respectively used to define a fixing structure for fixing safety helmet accessories formed on the outer surface of the safety helmet shell;

[0022] And when the injection mold is closed, the inner surface of the enclosing mechanism and the concave mold cavity of the moving mold half jointly define the outer surface contour of the safety helmet shell.

[0023] Furthermore, a chute inclined along the opening and closing direction of the injection mold is provided on the outer side surface of each enclosing mechanism, and a slider slidably matched with the chute is correspondingly arranged on the moving mold half, so that when the moving mold half moves along the mold opening direction, the cooperation between the slider and the chute drives the enclosing mechanism to move away from the center line of the injection mold.

[0024] Furthermore, limiting grooves are provided on both side surfaces of each enclosing mechanism, and limiting blocks that contact or abut against the limiting grooves at the end of the mold opening stroke are arranged on the moving mold half.

[0025] Furthermore, the glue feeding system includes a hot runner manifold accommodated inside the stationary mold half and at least one hot nozzle provided at the end of the hot runner manifold, and the outlet of the hot nozzle is arranged on the surface of the convex mold core of the stationary mold half to form the glue outlet of the glue feeding system.

[0026] Furthermore, a concave area for forming the raised mark on the outer surface of the safety helmet shell is provided on the surface of the concave mold cavity of the moving mold half, and the side wall of the concave area is inclined relative to the bottom surface of the concave area to form a draft angle.

[0027] Another object of an embodiment of the present invention is also to provide a production method of a safety helmet shell. The above-mentioned injection mold is used to perform the production method, including the following steps:

[0028] Mold closing step: Drive the moving mold half to move in the mold closing direction close to the stationary mold half, and close the injection mold under a preset mold closing pressure, so that the stationary mold half and the moving mold half are closely fitted to form a mold cavity for molding the safety helmet shell;

[0029] Injection step: Inject the molten plastic into the mold cavity through the glue outlet provided on the convex mold core of the stationary mold half under a preset injection pressure until it is full;

[0030] Pressure holding step: Hold the pressure of the molten plastic in the mold cavity under a preset pressure holding pressure and a preset pressure holding time;

[0031] Cooling step: Cool the plastic in the mold cavity through the cooling water channels in the injection mold until the safety helmet shell solidifies and reaches the preset demolding temperature, so that the safety helmet shell solidifies and forms and adheres to the stationary mold half;

[0032] Mold opening step: Drive the moving mold half to move in the mold opening direction away from the stationary mold half, so that the moving mold half is separated from the stationary mold half, and the formed safety helmet shell remains on the stationary mold half;

[0033] Stationary mold ejection step: Start the ejection mechanism associated with the stationary mold half to eject the formed safety helmet shell from the stationary mold half.

[0034] Further, before the injection step, it also includes: baking the plastic particles for injection at a preset drying temperature for a preset time;

[0035] After the stationary mold ejection step, it also includes: using an automated device to grab the ejected safety helmet shell, move it out of the injection mold area, and place it on a conveyor belt.

[0036] Another object of the present invention is to provide a safety helmet, including a safety helmet shell obtained by performing the production method of the safety helmet shell as described above, a top strap fixedly connected to the safety helmet shell, a cap band fixedly connected to the top strap, and a chin strap fixedly connected to the cap band.

[0037] The injection mold provided by the embodiment of the present invention adopts an inverted mold structure with a fixed mold half having a punch core and a movable mold half having a die cavity, and by setting the glue outlet of the gating system on the surface of the punch core of the fixed mold half, molten plastic is injected from the inner surface of the safety helmet shell, and the gate mark is left at a position inside the safety helmet shell that is not easily visible, completely eliminating the gate mark on the outer surface of the safety helmet shell, significantly improving the aesthetics of the outer surface of the safety helmet, making the appearance of the safety helmet smoother, cleaner, and more beautiful, enhancing the overall texture and market competitiveness of the product; at the same time, removing this potential structural weakness and stress concentration point of the outer surface gate helps to improve the structural integrity of the top area of the safety helmet and may have a positive impact on its impact resistance performance; by utilizing the characteristic that the plastic cools and shrinks to preferentially wrap around the punch core, it is ensured that the safety helmet shell remains stably on the fixed mold half side after mold opening, and then the ejection mechanism on the fixed mold half side (especially using a lifter) ejects it, simplifying the movable mold structure, making the demolding process more controllable and stable, facilitating automatic part taking, and at the same time, the ejection action of the ejection mechanism acts on the inner surface of the safety helmet, avoiding leaving ejector pin marks or other ejection marks on the outer surface, further ensuring the perfect appearance of the product; by setting an enclosing mechanism (usually a slider) and using the cooperation between the slider on the movable mold half and the chute on the enclosing mechanism to drive it to automatically move laterally during mold opening, a fixed structure with an undercut on the outer side of the safety helmet is reliably formed; at the same time, the design of the limit groove and the limit block ensures that the core pulling stroke of the enclosing mechanism is accurate, in place, and stable; at the same time, by adopting a hot runner gating system, cold runner condensate is eliminated, raw materials are saved, and the injection molding cycle is shortened; at the same time, by setting a recessed area with a draft angle on the movable mold die cavity, a raised logo that is completely integrated with the safety helmet shell body can be injection molded in one step, reducing subsequent processes and improving production efficiency. At the same time, since the raised logo is made of the same material as the safety helmet shell, it is extremely firm and durable, will not wear or fall off, ensuring the permanent display of the brand or information. At the same time, the design of the draft angle effectively solves the problem of smooth demolding of the raised logo and avoids product damage; it solves the problem of appearance defects existing in the production of the existing safety helmet shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 An exploded view of the injection mold in the first embodiment of the present invention from the first perspective;

[0039] Figure 2 An exploded view of the injection mold in the first embodiment of the present invention from the second perspective;

[0040] Figure 3 An exploded view of the injection mold in the first embodiment of the present invention from the third perspective;

[0041] Figure 4 An exploded view of the injection mold in the first embodiment of the present invention from the fourth perspective;

[0042] Figure 5 It is a schematic structural diagram of the injection mold in the first embodiment of the present invention when the mold is opened from the fifth perspective;

[0043] Figure 6 It is a schematic structural diagram of the injection mold in the first embodiment of the present invention when the mold is opened from the sixth perspective;

[0044] Figure 7 It is Figure 2 an enlarged view of the part circled Ⅲ in

[0045] Figure 8 It is Figure 3 an enlarged view of the part circled Ⅳ in

[0046] Figure 9 It is a flowchart of the production method of the safety helmet shell in the second embodiment of the present invention;

[0047] Figure 10 It is an exploded view of the safety helmet in the third embodiment of the present invention;

[0048] Figure 11 It is a schematic structural diagram of the safety helmet in the third embodiment of the present invention from the seventh perspective;

[0049] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0050] For the convenience of understanding the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0051] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there can also be a middle element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be a middle element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0053] Embodiment 1

[0054] Please refer to Figures 1 - 8 , which shows the injection mold in the first embodiment of the present invention. For the sake of convenience of description, only the parts related to the embodiments of the present invention are shown. The injection mold provided by the embodiments of the present invention is used to produce the safety helmet shell. The injection mold includes:

[0055] The fixed mold half 11, which includes a convex mold core for defining the inner surface contour of the safety helmet shell 10;

[0056] The movable mold half 12, which includes a concave mold cavity for defining the outer surface contour of the safety helmet shell 10. The concave mold cavity and the convex mold core jointly form a mold cavity when the injection mold is closed;

[0057] The gating system 13, the outlet of the gating system 13 is arranged on the surface of the convex mold core of the fixed mold half 11, and is used to introduce molten plastic into the mold cavity;

[0058] And the ejection mechanism 14, the movable structure of the ejection mechanism 14 can move relative to the fixed mold half 11, and is configured to eject the safety helmet shell 10 formed on the convex mold core from the fixed mold half 11 after the movable mold half 12 is separated from the fixed mold half 11.

[0059] Among them, in an embodiment of the present invention, the injection mold mainly includes a fixed mold half 11, a movable mold half 12, a gating system 13 and an ejection mechanism 14. Among them, the fixed mold half 11 constitutes the fixed part of the injection mold, and its core component is the convex mold core. The shape of the convex mold core precisely matches the inner surface contour of the safety helmet shell 10, and its surface finish and flatness directly affect the quality of the inner wall of the safety helmet shell 10.

[0060] Among them, the movable mold half 12 constitutes the movable part of the injection mold, and its core component is the concave mold cavity. The shape of the concave mold cavity precisely matches the outer surface contour of the safety helmet shell 10. When the injection mold is closed, the movable mold half 12 and the fixed mold half 11 are closed, and the concave mold cavity and the convex mold core are closely matched to jointly define a closed mold cavity, and the shape of this mold cavity is the shape of the safety helmet shell 10 to be produced.

[0061] The glue feeding system 13 is responsible for introducing the molten plastic raw material into the mold cavity. Different from the traditional injection mold in which the glue feeding port is set on the top of the fixed mold, which is specifically the concave mold, the glue outlet of the glue feeding system 13 of the embodiment of the present invention is set on the surface of the punch core of the fixed mold half 11. Usually, the glue outlet will be set at the top center of the punch core or close to the top center, corresponding to the top inner center of the helmet shell 10. By setting the glue outlet at the punch core (i.e., the corresponding position on the inner surface of the helmet shell 10), the gate mark can be left on the inner surface of the helmet shell 10 that is not easily observed, avoiding the gate scar that affects the appearance on the outer surface. At the same time, feeding from the top center is conducive to the uniform flow and filling of the molten plastic in the cavity, reducing defects such as weld marks, and improving the overall strength and appearance quality of the helmet shell 10.

[0062] The ejection mechanism 14 is used to remove the solidified helmet shell 10 from the injection mold after the injection molding is completed. The key is that the ejection mechanism 14 of the embodiment of the present invention is associated with the fixed mold half 11, and its movable structure (such as the moving part 142 and the inclined top 143 thereon) can move relative to the fixed mold half 11. During the mold opening process (the movable mold half 12 moves away from the fixed mold half 11), the movable mold half 12 is first separated from the fixed mold half 11. Due to plastic shrinkage and mold design, the molded helmet shell 10 will preferentially adhere to and remain on the punch core of the fixed mold half 11. Subsequently, the ejection mechanism 14 is started, and its movable structure acts on the helmet shell 10 to eject it from the punch core. Among them, for the helmet shell 10 with a relatively simple internal structure, it is usually easier to wrap tightly on the punch core. The fixed mold ejection design can ensure that the helmet shell 10 remains stably on the fixed mold half mold 11 side after mold opening, and then is ejected through a specially designed ejection mechanism 14, making the demolding process more stable and reliable, avoiding the problem of the helmet shell 10 possibly adhering to or falling between the movable mold half mold 12 and the fixed mold half mold 11 in the mold opening process, and also simplifying the design of the movable mold half mold 12 side.

[0063] Furthermore, in one embodiment of the present invention, the ejection mechanism 14 includes:

[0064] A driving component 141 fixedly mounted on the outside of the fixed mold half 11;

[0065] A moving component 142 which is transmission-connected to the driving component 141 and can reciprocate along the opening and closing direction of the injection mold under the drive of the driving component 141;

[0066] and at least one inclined top 143 mounted on the moving part 142;

[0067] A notch matching the lifter 143 is provided on the punch core of the fixed mold half 11. When the injection mold is closed and the moving part 142 is in the initial position, the top surface of the lifter 143 is embedded in the notch and flush with the surface of the punch core, jointly forming the contour that defines the inner surface of the safety helmet shell 10.

[0068] Specifically, the driving component 141 is usually a hydraulic cylinder or a pneumatic cylinder installed outside the fixed mold half 11 (such as on the side of the fixed mold half 11); the moving component 142 is usually an ejector plate (or push plate) connected to the piston rod of the driving component 141, and can reciprocate along the opening and closing direction of the injection mold (or parallel to this direction) under the drive of the driving component 141; the lifter 143 is usually at least one (usually multiple, distributed around the punch core) installed on the moving component 142. The shape and angle of the lifter 143 are carefully designed, and a notch matching the shape, size and angle of the lifter 143 is correspondingly provided on the punch core of the fixed mold half 11. When the injection mold is closed and the moving component 142 is in the initial position (non-ejecting state), the top of each lifter 143 is embedded in the corresponding notch, and its top surface is flush with the surface of the punch core for smooth transition, jointly forming a complete contour for defining the inner surface of the safety helmet shell 10. When the ejection mechanism 14 is activated, the driving component 141 drives the moving component 142 to move, and the moving component 142 drives the lifter 143 to displace along the ejection direction. The top surface of the lifter 143 applies force to the inner surface or inner edge of the safety helmet shell 10, and ejects it smoothly from the punch core. Therefore, by adopting the lifter 143 structure as part of the ejection mechanism 14, especially when used on the fixed mold half 11 side, effective ejection force can be provided under limited space conditions. At the same time, its embedded design ensures the integrity and smoothness of the inner surface of the safety helmet shell 10 during molding. At the same time, the ejection action acts on the inner surface of the safety helmet shell 10, avoiding leaving ejection marks on the key outer surface by using ejector pins, etc., and further ensuring the product appearance.

[0069] Further, in an embodiment of the present invention, in order to form a fixing structure on the outer surface of the safety helmet shell 10 for fixing safety helmet accessories (such as slots or buckles for lighting headlamps, warning lamps, cordless lamps, etc.), the injection mold further includes two enclosing mechanisms 15, and the two enclosing mechanisms 15 are respectively used to define the fixing structure for fixing safety helmet accessories formed on the outer surface of the safety helmet shell 10; and when the injection mold is closed, the inner surface of the enclosing mechanism 15 and the cavity of the female mold of the moving mold half 12 jointly define the outer surface contour of the safety helmet shell 10. The enclosing mechanism 15 is usually a sliding block or a lateral core. The two enclosing mechanisms 15 are located between the moving mold half 12 and the stationary mold half 11 and are symmetrically arranged on both sides of the mold cavity. When the injection mold is closed, the inner surface of each enclosing mechanism 15 participates in forming a part of the mold cavity and jointly defines the outer surface contour of the safety helmet shell 10 with the cavity of the female mold of the moving mold half 12, especially forming the above-mentioned fixing structure on the safety helmet shell 10. Therefore, by adding the enclosing mechanism 15, a complex structure or undercut feature on the outer side of the safety helmet shell 10 can be reliably formed on the injection mold, enhancing the functionality and accessory compatibility of the safety helmet. At the same time, since a complex lateral undercut structure can be directly formed in one injection process, secondary processing is avoided, the production efficiency and product precision are improved, and the strength and reliability of the fixing structure are ensured.

[0070] Further, in an embodiment of the present invention, since the fixing structure on the safety helmet shell 10 usually has an undercut, it is impossible to directly demold along the mold opening direction. Therefore, in order to smoothly demold these fixing structures during mold opening, the enclosing mechanism 15 needs to move laterally (away from the center line of the injection mold) during the mold opening process of the moving mold half 12 to release the fixing structure. Therefore, in the embodiment of the present invention, a chute 151 inclined along the opening and closing direction of the injection mold is provided on the outer side surface of each enclosing mechanism 15, and a slider 121 slidably engaged with the chute 151 is correspondingly provided on the moving mold half 12, so that when the moving mold half 12 moves along the mold opening direction, the cooperation between the slider 121 and the chute 151 drives the enclosing mechanism 15 to move away from the center line of the injection mold. That is, when the moving mold half 12 moves along the mold opening direction, the slider 121 fixed on the moving mold half 12 slides in the chute 151, and using the lateral component force generated by the inclined plane, the enclosing mechanism 15 is driven to move away from the center line of the injection mold (i.e., laterally). Therefore, the method of driving the enclosing mechanism 15 by the mold opening action of the moving mold has the characteristics of simple structure and reliable action, without an additional driving source, and can ensure that when the moving mold half 12 is opened to a certain distance, the lateral fixing structure has been completely disengaged, clearing the way for the subsequent ejection action.

[0071] Furthermore, in an embodiment of the present invention, in order to ensure that the enclosure mechanism 15 moves laterally into place and prevent it from moving excessively or wobbling at the end of the mold opening process, limiting grooves 152 are provided on both side surfaces of each enclosure mechanism 15, and limiting blocks 122 are provided on the moving mold half 12 that come into contact with or abut against the limiting grooves 152 at the end of the mold opening stroke. When the mold opening stroke of the moving mold half 12 approaches or reaches the end, the limiting block 122 will come into contact with or abut against a specific position (such as the end of the limiting groove 152) of the limiting groove 152. Therefore, by providing the limiting grooves 152 on the enclosure mechanism 15 and the limiting blocks 122 on the moving mold half 12, the end point of the lateral core-pulling stroke of the enclosure mechanism 15 can be precisely controlled, ensuring that the enclosure mechanism 15 completely disengages from the fixed structure area on the outer surface of the safety helmet shell 10 and providing a stable stopping position to prevent damage to the enclosure mechanism 15 or affecting subsequent automatic part taking. It should be noted that, Figure 5 and Figure 6 only as an example reference figure in the present invention, in order to clearly see the produced and formed safety helmet, the moving mold half 12 is extended out of the limiting groove 152 of the enclosure mechanism 15. It can be understood that during the actual production process, when the moving mold half 12 moves to the predetermined stroke and abuts against the end of the limiting groove 152, the moving mold half 12 stops moving or the moving mold half 12 continues to move and drives the enclosure mechanism 15 to move together through the limiting cooperation between the limiting groove 152 and the limiting block 122, and there will not be Figure 5 and Figure 6 the situation where the moving mold half 12 extends out of the limiting groove 152 of the enclosure mechanism 15 as shown.

[0072] Among them, in an embodiment of the present invention, the gating system 13 includes a hot runner manifold (not shown in the figure) accommodated inside the stationary mold half 11 and at least one hot nozzle 131 provided at the end of the hot runner manifold, and the outlet of the hot nozzle 131 is provided on the surface of the punch core of the stationary mold half 11, constituting the glue outlet of the gating system 13. By adopting the hot runner system, direct internal gating can be achieved without the traditional cold runner, avoiding gate scars on the outer surface of the safety helmet shell 10, improving the appearance quality of the product, reducing material waste, shortening the injection molding cycle, and improving production efficiency. At the same time, the hot runner system can more precisely control the temperature and pressure of the molten plastic, helping to improve the product quality and reduce internal stress. And by directly setting the hot nozzle 131 on the surface of the punch core, gate-free or minimal gate mark gating at the center point of the stationary mold half 11 is achieved, further enhancing the advantages of the aforementioned gating of the stationary mold half 11.

[0073] Furthermore, in one embodiment of the present invention, in order to form a raised logo such as a brand logo, certification mark or model on the outer surface of the helmet shell 10, a recessed area 123 for forming the raised logo on the outer surface of the helmet shell 10 is provided on the surface of the cavity of the movable mold half 12, that is, a recessed area 123 inversely corresponding to the required raised logo (such as logo, text) is provided on the cavity surface of the movable mold half 12, thereby achieving complete integration of the logo with the helmet shell 10 body. By using the same material for one-time molding, the logo is extremely firm and durable, and will not wear out or fall off like labeling or printing, thereby improving the overall sense and quality of the product. In order to ensure that the helmet shell 10 with the raised logo can be smoothly ejected from the movable mold cavity, the side wall of the recessed area 123 is inclined relative to the bottom surface of the recessed area 123 to form a draft angle. Therefore, by providing a recessed area 123 with a draft angle, it is ensured that the molded raised logo can be smoothly ejected from the cavity of the cavity when the mold is opened. Setting a sufficient draft angle can significantly reduce demoulding resistance, prevent the product from being stretched or deformed due to interference between the side wall of the logo and the injection mold during demoulding, and ensure the clarity and integrity of the logo.

[0074] In summary, for the injection mold in the above embodiments of the present invention, by adopting an inverted mold structure with a fixed mold half having a punch core and a movable mold half having a die cavity, and by setting the glue outlet of the feeding system on the surface of the punch core of the fixed mold half, molten plastic is injected from the inner surface of the safety helmet shell, and the gate mark is left at a position inside the safety helmet shell where it is not easily visible, completely eliminating the gate mark on the outer surface of the shell, significantly improving the aesthetics of the outer surface of the safety helmet, making the appearance of the safety helmet smoother, cleaner, and more beautiful, enhancing the overall texture and market competitiveness of the product; at the same time, removing this potential structural weakness and stress concentration point of the outer surface gate helps to improve the structural integrity of the top area of the safety helmet, which may have a positive impact on its impact resistance performance; by utilizing the characteristic that the plastic cools and shrinks to preferentially wrap around the punch core, it is ensured that the safety helmet shell remains stably on the fixed mold half side after mold opening, and then it is ejected by the ejection mechanism (especially using a lifter) on the fixed mold half side, simplifying the structure of the movable mold, making the demolding process more controllable and stable, facilitating automatic part picking, and at the same time, the ejection action of the ejection mechanism acts on the inner surface of the safety helmet, avoiding leaving ejector pin marks or other ejection marks on the outer surface, further ensuring the perfect appearance of the product; by setting an enclosing mechanism (usually a slider), and using the cooperation between the slider on the movable mold half and the chute on the enclosing mechanism to drive it to move automatically laterally during mold opening, a fixed structure with an undercut on the outer side of the safety helmet is reliably formed; at the same time, the design of the limit groove and the limit block ensures the accurate, in-place, and stable core-pulling stroke of the enclosing mechanism; at the same time, by adopting a hot runner feeding system, cold runner condensate is eliminated, raw materials are saved, and the injection molding cycle is shortened; at the same time, by setting a recessed area with a draft angle on the movable mold die, a raised logo that is completely integrated with the safety helmet shell body can be injection molded in one step, reducing subsequent processes and improving production efficiency. At the same time, since the raised logo is made of the same material as the safety helmet shell, it is extremely firm and durable, will not wear or fall off, ensuring the permanent display of the brand or information. At the same time, the design of the draft angle effectively solves the problem of smooth demolding of the raised logo and avoids product damage; it solves the problem of appearance defects existing in the production of the existing safety helmet shell.

[0075] Embodiment 2

[0076] Please refer to Figure 9 , which shows the production method of the safety helmet shell in the second embodiment of the present invention. For the convenience of description, only the parts related to the embodiments of the present invention are shown. The production method of the safety helmet shell provided by the embodiments of the present invention uses the injection mold described in the foregoing embodiments to execute the production method, including the following steps:

[0077] Step S10, mold closing step: Drive the movable mold half to move in the mold closing direction close to the fixed mold half, and close the injection mold under a preset mold closing pressure, so that the fixed mold half and the movable mold half are closely matched to form a mold cavity for molding the safety helmet shell;

[0078] Among them, in an embodiment of the present invention, the injection mold is started, and the moving half mold is driven to move in the mold closing direction towards the fixed half mold. During this process, if the injection mold includes an enclosing mechanism, during this process, the slider on the moving half mold enters the chute of the enclosing mechanism, driving the enclosing mechanism to move towards the center line of the injection mold to a predetermined working position, ensuring that its inner forming surface and the cavity of the female mold jointly form a complete outer contour. Finally, the moving half mold and the fixed half mold are tightly closed under a preset mold closing pressure (for example, 100 - 200 tons or higher, depending on the product size and material), ensuring good sealing of the parting surface of the injection mold and the mating surfaces of all moving parts, and forming a complete mold cavity. At this time, the injection mold can withstand subsequent high-pressure injection and pressure holding, ensuring the dimensional accuracy of the product and preventing material overflow.

[0079] Step S20, injection step: Inject the molten plastic into the mold cavity through the glue outlet provided on the core of the male mold of the fixed half mold at a preset injection pressure until it is full.

[0080] Among them, in an embodiment of the present invention, before the above step S20, it further includes:

[0081] Bake the plastic particles for injection at a preset drying temperature for a preset time.

[0082] Specifically, select engineering plastic particles suitable for the production of safety helmet shells, such as HDPE, ABS, PC, or PC / ABS, etc. Then perform sufficient drying treatment on the selected plastic particles. For example, bake HDPE at 80 - 100 °C for 2 - 4 hours to remove the moisture in the plastic, avoid defects such as bubbles and silver streaks during the injection process, and ensure the product quality.

[0083] Furthermore, add the processed plastic particles to the hopper of the injection mold. The injection device of the injection mold heats and melts the plastic in the hopper (for example, reaches the appropriate injection temperature of the material), and through the nozzle, docks with the glue inlet system of the injection mold (for example, the inlet of the hot runner system), and injects the molten plastic into the closed mold cavity through the hot runner system and the glue outlet (internal gate) on the fixed half mold at a preset injection pressure and speed until the plastic melt basically fills the entire mold cavity.

[0084] Step S30, pressure holding step: Hold the molten plastic in the mold cavity under a preset pressure holding pressure and a preset pressure holding time.

[0085] Among them, in an embodiment of the present invention, after the injection filling is basically completed, it switches to the holding pressure stage. With a holding pressure that is lower than the injection pressure but still relatively high (for example, 50%-80% of the injection peak pressure), within a preset holding time (for example, 10-30 seconds), a small amount of molten material is continuously replenished into the mold cavity to compensate for the volume shrinkage of the plastic during the cooling process, ensuring that the contour of the safety helmet shell is clear and the dimensions are stable, and reducing defects such as sink marks and depressions. Among them, the pressure is effectively transmitted through the internal gate (gate).

[0086] Step S40, cooling step: Cooling the plastic in the mold cavity through the cooling water channels in the injection mold until the safety helmet shell is solidified and reaches the preset demolding temperature, so that the safety helmet shell is solidified and formed and adheres to the fixed mold half;

[0087] Among them, in an embodiment of the present invention, after the holding pressure ends, the injection mold continues to remain in the closed state. Start the cooling water channel system inside the injection mold (not detailed, but a standard configuration of the injection mold), circulate and introduce a cooling medium (such as cooling water) to forcibly cool the plastic in the mold cavity, so that the molten plastic cools and solidifies quickly. Due to the inverted mold structure of the fixed mold half with a punch core and the moving mold half with a die cavity, the formed safety helmet shell is mainly coated on the punch core of the fixed mold half. The cooling water channel system needs to effectively cool the fixed mold punch and the moving mold die. In particular, for the area near the hot runner nozzle on the fixed mold half side, it may be necessary to strengthen the cooling to balance the heat and avoid local overheating affecting the curing. Among them, the cooling time usually accounts for a relatively large part of the entire injection cycle (for example, more than 60%), and it needs to be long enough to completely solidify the safety helmet shell, achieve sufficient strength and rigidity until the overall safety helmet shell is reduced to the preset demolding temperature that can withstand the demolding force. During this process, due to the shrinkage characteristics of the plastic and the injection mold design, the solidified safety helmet shell will tend to tightly wrap around the punch core of the fixed mold half.

[0088] Step S50, mold opening step: Drive the moving mold half to move in the mold opening direction away from the fixed mold half, so that the moving mold half is separated from the fixed mold half, and the formed safety helmet shell remains on the fixed mold half;

[0089] Among them, in an embodiment of the present invention, after reaching the preset cooling time, the injection mold drives the moving mold half to move in the mold opening direction away from the fixed mold half and separates from the fixed mold half. Due to the shrinkage characteristics of the plastic, the relatively smooth outer surface of the shell, and the demolding slope of the side wall of the marked depression area on the moving mold die, the outer surface of the shell is easy to separate from the moving mold die. At the same time, due to the holding force and the cooperation of the inner surface structure with the ejector mechanism components in the fixed mold half, the formed safety helmet shell will reliably remain on the punch core of the fixed mold half.

[0090] Among them, if the injection mold includes an enclosure mechanism, during the retreat of the movable mold half, the cooperation between the slider on the movable mold half and the slide groove of the enclosure mechanism will drive the enclosure mechanism to slide sideways, complete the side core pulling action, release the fixed structure on the outside of the helmet shell, and enable the fixed structure with undercut features to be demolded smoothly. When the movable mold half continues to rise to the predetermined mold opening stroke end point, the limit block on the movable mold half contacts the limit groove on the enclosure mechanism. During this process, the helmet shell always remains on the fixed mold half.

[0091] Step S60, fixed mold ejection step: start the ejection mechanism associated with the fixed mold half mold to eject the formed helmet shell from the fixed mold half mold;

[0092] Among them, in one embodiment of the present invention, after the movable mold half is fully opened or moved to a predetermined position, the ejection mechanism associated with the fixed mold half is started. The driving component (such as a hydraulic cylinder) pushes the movable component (such as an ejector plate) forward, and the multiple inclined ejectors installed on the movable component slide upward accordingly, and their top surfaces contact and push the inner surface or inner edge of the helmet shell, so that the solidified helmet shell is smoothly ejected and peeled off from the convex mold core of the fixed mold half, and the demoulding is completed, completing the entire molding cycle.

[0093] Furthermore, in one embodiment of the present invention, after the above-mentioned fixed mold ejection step, an automated pickup and conveying step is also included, specifically, using automated equipment to grab the ejected helmet shell and move it out of the injection mold area and place it on a conveyor belt. Specifically, use automated equipment (such as a manipulator or a robot arm) to grab the ejected helmet shell from the working area of ​​the injection mold (usually in front of or above the fixed mold half side), move the grabbed helmet shell out of the injection mold area, and place it on a conveyor belt or other subsequent processing stations for subsequent cooling, inspection or assembly work. At this time, the injection mold is reset (the moving part descends, and the inclined top returns to its position) and is ready for the next production cycle.

[0094] Embodiment 3

[0095] See also Figures 10 - 11 , shown is a safety helmet in the third embodiment of the present invention. For the convenience of explanation, only the parts related to the embodiment of the present invention are shown. The safety helmet provided by the embodiment of the present invention includes a safety helmet shell 10 obtained by executing the production method of the safety helmet shell described in the above embodiment, a top strap 20 connected and fixed to the safety helmet shell 10, a cap hoop 30 connected and fixed to the top strap 20, and a chin strap 40 connected and fixed to the cap hoop 30. In one embodiment of the present invention, the safety helmet also includes a sweat-absorbing belt 50 fixedly connected to the cap hoop 30.

[0096] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0097] The above-described embodiments merely represent several implementation manners of the present invention. The descriptions thereof are relatively specific and detailed, but should not be construed as a limitation on the scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. An injection mold, characterized in that: Used to produce a helmet shell, the injection mold comprises: A fixed mold half, comprising a male mold core for defining the inner surface contour of the helmet shell; The movable mold half comprises a concave mold cavity for defining the outer surface contour of the helmet shell, wherein the concave mold cavity and the convex mold core jointly form a mold cavity when the injection mold is closed; A glue feeding system, wherein the glue outlet of the glue feeding system is arranged on the surface of the male core of the fixed mold half, and is used to introduce molten plastic into the mold cavity; and an ejection mechanism, wherein the movable structure of the ejection mechanism can move relative to the fixed mold half and is configured to eject the helmet shell formed on the punch core from the fixed mold half after the movable mold half is separated from the fixed mold half.

2. The injection mold according to claim 1, characterized in that: The ejection mechanism comprises: A driving component fixedly mounted on the outside of the fixed mold half; A moving component that is drivingly connected to the driving component and can reciprocate along the opening and closing direction of the injection mold under the drive of the driving component; and at least one inclined roof mounted on said moving member; A notch matching the inclined top is provided on the core of the punch of the fixed mold half; when the injection mold is closed and the movable part is in the initial position, the top surface of the inclined top is embedded in the notch and is flush with the surface of the punch core, together forming a contour that defines the inner surface of the helmet shell.

3. The injection mold according to claim 1, characterized in that: The injection mold further comprises two enclosure mechanisms, and the two enclosure mechanisms are respectively used to define a fixing structure formed on the outer surface of the helmet shell for fixing the helmet accessories; When the injection mold is closed, the inner surface of the enclosure mechanism and the concave mold cavity of the movable mold half jointly define the outer surface contour of the helmet shell.

4. The injection mold according to claim 3, characterized in that: A slide groove is provided on the outer side surface of each of the enclosing mechanisms and is inclined along the opening and closing direction of the injection mold. A slider that slidably cooperates with the slide groove is correspondingly provided on the movable mold half, so that when the movable mold half moves along the mold opening direction, the cooperation between the slider and the slide groove drives the enclosing mechanism to move in a direction away from the center line of the injection mold.

5. The injection mold according to claim 3, characterized in that: Limiting grooves are arranged on both side surfaces of each of the enclosing mechanisms, and limiting blocks are arranged on the movable mold half, which are in contact with or abut against the limiting grooves at the end of the mold opening stroke.

6. The injection mold according to claim 1, characterized in that: The glue feeding system includes a hot runner manifold accommodated inside the fixed mold half and at least one hot nozzle arranged at the end of the hot runner manifold, and the outlet of the hot nozzle is arranged on the surface of the male mold core of the fixed mold half, forming the glue outlet of the glue feeding system.

7. The injection mold according to claim 1, characterized in that: A recessed area for molding the raised mark on the outer surface of the helmet shell is provided on the surface of the female mold cavity of the movable mold half, and the side wall of the recessed area is inclined relative to the bottom surface of the recessed area to form a draft angle.

8. A method for producing a helmet shell, characterized in that: The production method is performed using the injection mold according to any one of claims 1 to 7, comprising the following steps: Mold closing step: driving the movable mold half to move in a mold closing direction close to the fixed mold half, and closing the injection mold under a preset mold closing pressure, so that the fixed mold half and the movable mold half are closely matched to form a mold cavity for molding the helmet shell; Injection step: injecting molten plastic into the mold cavity through a plastic outlet provided on the male mold core of the fixed mold half at a preset injection pressure until the mold cavity is full; Holding step: holding the molten plastic in the mold cavity at a preset holding pressure and a preset holding time; Cooling step: cooling the plastic in the mold cavity through the cooling water channel in the injection mold until the helmet shell is solidified and reaches a preset demoulding temperature, so that the helmet shell is solidified and attached to the fixed mold half; Mold opening step: driving the movable mold half to move in a mold opening direction away from the fixed mold half, so that the movable mold half is separated from the fixed mold half, and the molded helmet shell is kept on the fixed mold half; Fixed mold ejection step: starting the ejection mechanism associated with the fixed mold half mold to eject the formed helmet shell from the fixed mold half mold.

9. The method for producing a helmet shell according to claim 8, characterized in that: Before the injection step, the step further includes: baking the plastic particles for injection molding at a preset drying temperature for a preset time; After the fixed mold ejection step, the method further includes: using automated equipment to grab the ejected helmet shell and move it out of the injection mold area and place it on a conveyor belt.

10. A safety helmet, characterized in that: It comprises a safety helmet shell obtained by executing the production method of the safety helmet shell as described in any one of claims 8 to 9, a top strap connected and fixed to the safety helmet shell, a hat hoop connected and fixed to the top strap, and a chin strap connected and fixed to the hat hoop.

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