Earplug preconditioning device based on toothed compression mechanism and method of manufacturing the same

Abstract

This invention belongs to the field of personal protective equipment technology, specifically relating to an earplug pretreatment device based on a toothed compression mechanism and its preparation method. It includes: a main shell comprising a left shell and a right shell connected by a snap-fit ​​structure, both the left and right shells having a central opening on their inner sides; and a toothed compression module comprising bidirectional meshing racks disposed on the inner sides of the left and right shells around the central opening. The bidirectional meshing racks are used to mesh with each other and compress the earplug located within the central opening when the left and right shells are closed. Through the coordinated design of the toothed compression mechanism and the limiting snap-fit, non-contact operation is achieved, effectively eliminating the risk of bacterial contamination and improving hygiene. Tests show that the bacterial content on the surface of earplugs treated using this device is reduced by more than 85% compared to the traditional finger compression method.

Description

Technical Field

[0001] The invention belongs to the field of personal protective equipment technology, specifically relating to an earplug pretreatment device based on a toothed compression mechanism and its preparation method. Through the synergistic effect of the toothed meshing structure and the limiting buckle, standardized compression of the earplug is achieved, solving the hygiene hazards and inconvenience caused by traditional finger rubbing. Background Technology

[0002] With increasing awareness of industrial noise protection, inert foam earplugs have become widely used in high-noise environments such as industrial sites, airports, and construction sites due to their excellent sound insulation and comfort. However, traditional earplug usage methods have significant drawbacks. Currently, users typically compress the foam earplugs by rubbing them with their fingers before inserting them into the ear canal. This method has the following main problems: First, the operation is highly uncontrollable. The force of rubbing with fingers is difficult to quantify, resulting in uneven compression of the earplugs. Actual measurements show that the diameter deviation often exceeds 0.5mm, and the rebound time difference can be more than 2 seconds, affecting the sealing effect of the earplugs in the ear canal and the wearing comfort.

[0003] Secondly, there are significant hygiene risks. Bacteria on the hands (such as Escherichia coli and Staphylococcus aureus) can be transmitted to the surface of the earplugs through contact, and then come into contact with the ear canal mucosa, increasing the risk of ear canal infection. According to relevant medical research, approximately 15% of ear canal infections can be traced back to exogenous bacterial contamination.

[0004] In addition, traditional methods are inconvenient to operate, especially in work environments where earplugs need to be worn and removed frequently, such as when communication with others is required and protection needs to be restored immediately.

[0005] Therefore, there is an urgent need for an earplug pretreatment device that can solve the above problems, achieve standardized compression treatment of earplugs, and reduce hygiene risks. Summary of the Invention

[0006] The purpose of this invention is to provide an earplug pretreatment device based on a toothed compression mechanism and its preparation method, so as to solve the problems of uneven earplug compression, high hygiene risks and inconvenient operation in the prior art.

[0007] This invention discloses an earplug pretreatment device based on a toothed compression mechanism, comprising: The main body shell includes a left shell and a right shell connected by a snap-fit ​​structure, and both the left and right shells have a central opening on their inner sides; and The toothed compression module includes bidirectional meshing racks disposed inside the left and right housings around a central opening. The bidirectional meshing racks are used to mesh with each other and compress the earplug located in the central opening when the left and right housings are closed.

[0008] Preferably, the main shell is integrally molded from polypropylene material, and the flexural modulus of the polypropylene material is greater than or equal to 3000MPa.

[0009] Preferably, the width of the central opening is 11mm, and the edge of the central opening is provided with a rounded corner with a radius of 0.5mm for placing uncompressed earplugs with a diameter of 10mm to 12mm.

[0010] Preferably, the bidirectional meshing rack has at least four trapezoidal teeth distributed on one side, with a tooth pitch of 2 mm between adjacent trapezoidal teeth.

[0011] Preferably, the bidirectional meshing rack is designed so that the diameter of the earbud after compression is 3.0±0.1mm.

[0012] Preferably, the surfaces of the left and right shells are matte-finished with a surface roughness Ra of 3.2 μm. Preferably, the weight of the main shell is less than 10 g.

[0013] Preferably, the snap-fit ​​connection structure is made of the same material as the main shell, which allows it to be repeatedly bent and folded without breaking.

[0014] As a preferred option, the trapezoidal tooth design of the bidirectional meshing rack is used to optimize stress distribution and prevent the earplugs from tearing during compression.

[0015] The method for preparing the earplug pretreatment device includes the following steps: Polypropylene material is placed in an injection mold, and the cavity shape of the injection mold matches the shape of the earplug pretreatment device. Polypropylene material is injection molded to form an integrated main shell, including a left shell, a right shell, a snap-fit ​​connection structure, and a two-way meshing rack; The molded main shell is given a matte finish to achieve a surface roughness Ra of 3.2μm; and the molded main shell is subjected to quality inspection to ensure that the weight is less than 10g and that the bidirectional meshing rack can achieve an earbud diameter of 3.0±0.1mm after compression.

[0016] The earplug pretreatment device provided by the present invention has the following beneficial effects: 1. Through the coordinated design of the toothed compression mechanism and the limiting buckle, non-contact operation is achieved, effectively eliminating the risk of bacterial contamination and improving hygiene. Tests show that the bacterial content on the surface of earplugs treated with this device is reduced by more than 85% compared to the traditional finger compression method.

[0017] 2. Made of lightweight polypropylene material in one piece, the weight is controlled below 10g, making it easy to carry and fit into pockets, thus improving portability.

[0018] 3. Through a progressive compression design, the axial deformation of the earbuds is ensured to be uniform, and the diameter deviation after compression is controlled within 0.1mm, which is significantly better than the traditional finger compression method (deviation >0.5mm), thus improving the sealing effect and wearing comfort of the earbuds.

[0019] 4. The trapezoidal tooth design optimizes stress distribution, avoids the risk of tearing of the sponge material during compression, and extends the lifespan of the earplugs. Experiments show that the number of times the earplugs can be reused increases by an average of 30% after compression treatment using this device.

[0020] 5. The one-handed operation design improves ease of use, making it especially suitable for work environments that require frequent wearing and removal of earplugs. Attached Figure Description

[0021] Figure 1 This is a top view of the earplug pretreatment device of the present invention, showing the earplug placement state; Figure 2 This is a schematic diagram of the operation flow of the earplug pretreatment device of the present invention, including three stages: earplug placement, compression process and removal; Figure 3 This is a schematic diagram of the earplug pretreatment device of the present invention in its unfolded state, showing the main components and their numbers; Figure 4 This is a three-dimensional structural diagram of the earplug pretreatment device of the present invention. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, the embodiments of the present invention are not limited thereto, and all equivalent changes or substitutions made by those skilled in the art based on the technical solutions of the present invention fall within the protection scope of the present invention.

[0023] like Figures 1 to 4 As shown, the earplug pretreatment device based on a toothed compression mechanism provided by the present invention includes a main body shell and a toothed compression module.

[0024] The main body shell includes a left shell 401 and a right shell 501 connected by a snap-fit ​​connection structure 301. Both the left shell 401 and the right shell 501 have a central opening 101 on their inner sides. Preferably, the left shell 401 and the right shell 501 have a semi-circular design, forming an overall clamshell-like structure for easy one-handed operation. The central opening 101 is used to hold an uncompressed earbud, ensuring the earbud remains stable during compression.

[0025] The toothed compression module includes a bidirectional meshing rack 201 disposed inside the left housing 401 and the right housing 501, surrounding the central opening 101. The bidirectional meshing rack 201 is used to mesh with each other and compress the earplug located within the central opening 101 when the left housing 401 and the right housing 501 are closed. In the embodiments of the present invention, the design of the bidirectional meshing rack 201 is the core innovation of this device. Through a progressive meshing structure, it achieves uniform compression of the earplug, avoiding the problem of uneven pressure in the traditional finger-rubbing method.

[0026] In particular, a micro-arc transition structure is provided at the end region of the bidirectional meshing rack 201. This structure provides a smoother pressure transition during the initial contact of the rack, further reducing the impact stress on the earplug material and making the compression process smoother and more gradual. This detailed design is especially important for ultra-soft earplug materials with low density, as it can effectively prevent structural damage to the material during the initial stage of compression.

[0027] In a preferred embodiment of the invention, the main outer shell is integrally molded from polypropylene material, the flexural modulus of which is greater than or equal to 3000 MPa. Polypropylene is chosen here primarily because of its excellent mechanical properties, low density, and good biocompatibility. A flexural modulus of 3000 MPa or more ensures that the device maintains sufficient structural strength during repeated use, while remaining lightweight and easy to carry. Furthermore, polypropylene has good chemical resistance and temperature resistance, making it suitable for use in various working environments.

[0028] It is worth mentioning that this invention adds 0.5% to 1.5% antibacterial agent to the material formulation, giving the device itself a certain degree of antibacterial properties and further reducing hygiene risks during use. Simultaneously, a small amount of ultraviolet stabilizer is added to the material, improving the product's weather resistance in outdoor environments and extending its service life by more than 40% under direct sunlight. Although these material modification measures slightly increase the cost, they significantly improve the product's practicality and durability.

[0029] like Figure 1 and Figure 3 As shown, in another embodiment of the present invention, the width of the central opening 101 is 11 mm, and the edge of the central opening 101 is provided with a rounded corner with a radius of 0.5 mm for placing an uncompressed earplug with a diameter of 10 mm to 12 mm.

[0030] The central opening 101 is designed with a width of 11mm, based on the standard diameter (10-12mm) of commonly available inert foam earplugs. The width is slightly larger than the earplug diameter, making it easy to insert the earplug without being too loose and causing it to shift position during compression. The edges are rounded with 0.5mm corners, preventing damage to the earplug material from sharp angles and improving comfort. Extensive testing has shown that this design parameter achieves the optimal balance between fit and ease of use.

[0031] At the bottom of the central opening 101, a cleverly designed slightly concave positioning protrusion, approximately 0.2mm high, provides a slight friction when placing the earbuds, preventing them from slipping or shifting during operation without damaging the earbud material. This seemingly small but practical design detail significantly improves ease of use, especially stability when used outdoors in windy conditions or while moving.

[0032] Reference Figure 3 and Figure 4 In one embodiment of the present invention, the bidirectional meshing rack 201 has at least four trapezoidal teeth distributed on one side, and the tooth pitch between adjacent trapezoidal teeth is 2 mm.

[0033] The number and pitch of the trapezoidal teeth are key parameters carefully designed. At least four trapezoidal teeth on each side ensure sufficient contact area and pressure distribution during compression. The tooth pitch of 2mm is determined based on the compression characteristics and deformation behavior of the sponge material. This tooth pitch design achieves a good balance between compression efficiency and stress distribution, enabling effective compression while avoiding sponge tearing caused by localized stress concentration. Furthermore, the shape of the trapezoidal teeth optimizes stress distribution; compared to rectangular or triangular teeth, trapezoidal teeth exhibit superior performance in both compression and material protection.

[0034] Furthermore, a height difference of approximately 0.3mm is designed between the top and bottom surfaces of the trapezoidal teeth, creating a slight tilt angle. This design allows the rack to generate a small axial guiding force during engagement, helping the earplug material maintain axial stability during compression and avoiding uneven compression caused by lateral deformation. This tooth design with a guiding function is a significant improvement over conventional trapezoidal teeth, increasing compression accuracy by approximately 15%.

[0035] In a preferred embodiment of the present invention, the bidirectional meshing rack 201 is designed such that the diameter of the earplug after compression is 3.0±0.1mm.

[0036] Controlling the diameter of the compressed earplug is a crucial technical indicator of this device. The setting of 3.0 ± 0.1 mm is based on a comprehensive consideration of human ear canal anatomy and earplug comfort. The normal adult external auditory canal diameter is approximately 7–9 mm. Compressing the earplug to around 3.0 mm ensures smooth insertion into the ear canal while allowing for sufficient rebound after insertion, resulting in a good seal. A deviation within ± 0.1 mm is significantly better than the traditional finger-rubbing method (deviation > 0.5 mm), ensuring precise and consistent compression, and improving wearing comfort and noise insulation.

[0037] This invention also incorporates a set of invisible positioning posts and holes inside the left and right housings. When compression reaches a preset depth, the positioning posts precisely insert into the positioning holes, generating slight tactile feedback so that the user can perceive that the compression has reached its optimal state. This human-computer interaction design detail allows for precise compression without visual confirmation, making it particularly suitable for use in dark environments or scenarios requiring rapid operation.

[0038] In one embodiment of the present invention, the surfaces of the left housing 401 and the right housing 501 are matte-finished, with a surface roughness Ra of 3.2 μm.

[0039] The matte finish is an important design detail that considers user experience. A matte surface with a roughness Ra of 3.2μm provides moderate friction, preventing slippage during one-handed operation while avoiding discomfort caused by excessive roughness. Furthermore, the matte finish reduces light reflection, maintaining good visibility under various lighting conditions for easy observation and operation. Compared to smooth or excessively rough surfaces, this roughness parameter achieves the optimal balance between grip, aesthetics, and wear resistance.

[0040] In particular, a honeycomb-like micro-textured structure with a texture depth of approximately 0.1mm is designed on the outer surfaces of the left and right shells. This special texture not only provides better anti-slip properties but also effectively reduces material usage by about 5% while maintaining sufficient structural strength. This design is inspired by biomimetic, mimicking the high-strength and lightweight characteristics of a honeycomb structure, making the product more environmentally friendly and material-saving while ensuring functionality.

[0041] In one embodiment of the present invention, the weight of the main body shell is less than 10g.

[0042] Weight control is a key indicator for portable devices. This device weighs less than 10g, making it easy for users to carry without causing any burden. This weight target is achieved through optimized structural design and material selection, minimizing weight while ensuring sufficient mechanical strength. Compared to similar devices on the market (typically weighing 15-20g), this device has a significant portability advantage, making it particularly suitable for scenarios requiring prolonged carrying or frequent use.

[0043] By employing a variable wall thickness design in non-critical areas, the wall thickness is gradually reduced from the standard 1.5mm to 0.8mm in critical non-load-bearing areas, further reducing the overall weight by approximately 15% while maintaining structural strength. This refined wall thickness optimization design requires sophisticated mold processing technology and flow analysis support, representing a key technological breakthrough in the product's lightweight design.

[0044] like Figure 3 As shown, in one embodiment of the present invention, the snap-fit ​​connection structure 301 is made of the same material as the main body shell and can be repeatedly bent and folded without breaking.

[0045] The snap-fit ​​connection structure 301 is a key component ensuring reliable opening and closing of the device. Made of the same polypropylene material as the main shell, it is manufactured using a one-piece molding process, eliminating seams and connection points and improving structural strength and service life. This structural design allows for repeated opening and closing of the device; according to durability tests, it can withstand no less than 10,000 opening and closing operations under normal use conditions without breakage or functional degradation. This feature significantly extends the device's service life and improves the product's economic efficiency.

[0046] It is worth noting that the snap-fit ​​connection structure 301 adopts a double thin-wall design, with a central thickness of only 0.6mm, gradually transitioning to a standard thickness on both sides, forming a flexible connection similar to a butterfly hinge. This design ensures sufficient flexibility while providing the necessary resilience, allowing the device to maintain appropriate operating resistance during opening and closing, avoiding problems such as accidental closure or excessive looseness. Simultaneously, a special rounded transition design is used in the stress concentration areas of the connection structure, effectively reducing stress concentration and further improving service life.

[0047] Reference Figure 3 and Figure 4 In one embodiment of the present invention, the trapezoidal tooth design of the bidirectional meshing rack 201 is used to optimize stress distribution and prevent the earplug from tearing during compression.

[0048] The trapezoidal teeth have a carefully designed geometry. Compared to rectangular or acute-angled teeth, trapezoidal teeth offer a more progressive contact characteristic, enabling them to evenly distribute stress during compression. Finite element analysis and experimental verification show that the maximum stress generated by trapezoidal teeth during compression is reduced by approximately 35% compared to rectangular teeth and by approximately 50% compared to triangular teeth. This design significantly reduces the risk of tearing in the earplug material during compression, extending the earplug's lifespan. This advantage is particularly pronounced for high-density, sound-insulating, inert foam earplugs.

[0049] This invention also incorporates a micron-level wavy texture on the surface of the trapezoidal teeth, with a texture depth of approximately 0.05 mm and a spacing of 0.2 mm. This microtexture significantly reduces the frictional resistance between the tooth surface and the earplug material, making the compression process smoother and reducing damage to the sponge material caused by friction. Experiments show that the trapezoidal teeth with added microtexture can reduce the operating force by approximately 20% compared to trapezoidal teeth with a smooth surface, while also improving compression uniformity. Although this microtexture design increases the complexity of mold processing, it significantly improves product performance, reflecting an extreme pursuit of detail.

[0050] The present invention also provides a method for preparing the above-mentioned earplug pretreatment device, comprising the following steps: First, polypropylene material is placed in an injection mold, the cavity shape of which matches the shape of the earplug pretreatment device. In a preferred embodiment of the invention, the selected polypropylene material is medical-grade polypropylene with a flexural modulus ≥3000MPa and a melt index between 8 and 12 g / 10min. This parameter range ensures good flowability during injection molding and mechanical strength after molding. The injection mold is manufactured using precision CNC machining, and the surface roughness of the cavity is controlled to Ra≤0.8μm to ensure the dimensional accuracy and surface quality of the molded product.

[0051] Secondly, the polypropylene material is injection molded to form an integrated outer shell, including a left shell 401, a right shell 501, a snap-fit ​​connection structure 301, and a bidirectional meshing rack 201. During the injection molding process, the material temperature is controlled at 210~230℃, the mold temperature at 50~60℃, the injection pressure at 80~100MPa, and the holding time at 8~12 seconds. Precise control of these process parameters ensures that the molded product is free of internal bubbles, has minimal warpage, and exhibits good dimensional stability. The integrated molding process eliminates connection points and seams during assembly, improving the overall strength and service life of the product.

[0052] In particular, variable temperature control technology was employed during the injection molding process. This involved maintaining a high mold temperature during the injection phase to ensure the material fully fills the complex structure, while gradually reducing the mold temperature during the holding and cooling phases to optimize the internal stress distribution. This innovative process effectively solved the problem of simultaneously molding thin-walled areas (such as the snap-fit ​​connection structure 301) and standard-thickness areas, resulting in a more uniform internal structure and lower residual stress in all parts of the product, thereby improving the product's durability and dimensional stability.

[0053] Next, the formed outer shell undergoes a matte surface treatment to achieve a surface roughness Ra of 3.2 μm. The surface treatment employs a micro-blasting process using 120-mesh alumina sand, with the blasting pressure controlled at 0.4–0.5 MPa, the blasting distance at 100–150 mm, and the processing time at 10–15 seconds. This combination of process parameters produces a uniform matte finish without excessively damaging the product's surface structure.

[0054] Finally, the formed main shell undergoes quality inspection to ensure its weight is less than 10g and that the bidirectional meshing rack 201 can achieve an earplug diameter of 3.0±0.1mm after compression. Quality inspection includes four aspects: dimensional inspection, weight inspection, functional testing, and appearance inspection. Dimensional inspection uses precision digital calipers, and weight inspection uses an electronic balance with an accuracy of 0.01g. Functional testing uses standard 10mm diameter test earplugs to check the diameter and uniformity after compression. Appearance inspection mainly focuses on surface defects, color consistency, and marking clarity. Through this series of rigorous quality control measures, the consistency and reliability of the product are ensured.

[0055] The above preparation method can be used to mass-produce earplug pretreatment devices with stable performance and reliable quality to meet market demand.

[0056] The working principle of this invention is as follows: When in use, first place the cylindrical earplug horizontally into the central opening 101, ensuring that the axis is perpendicular to the direction of the rack movement; then press the two sides of the shell with one hand, so that the left and right shells mesh with each other, and the rack 201 gradually meshes and compresses the earplug until the left and right shells 401 and 501 are locked; finally, take out the top of the compressed slender earplug by hand and insert it directly into the ear canal. The whole process does not require the fingers to make large-area contact with the contact surface between the earplug and the ear canal, effectively reducing the hygiene risk.

[0057] In summary, the earplug pretreatment device and its preparation method based on a toothed compression mechanism provided by this invention effectively solve the problems of hygiene risks, inconvenient operation, and uneven compression in traditional earplug pretreatment methods through innovative structural design and precise process control, and have important practical value and promotion significance.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An earplug pretreatment device based on a toothed compression mechanism, characterized in that, include: The main body shell includes a left shell (401) and a right shell (501) connected by a snap-fit ​​connection structure (301). The left shell (401) and the right shell (501) are semi-circular in design and have an overall open clamshell-like structure. The inner sides of the left shell (401) and the right shell (501) are provided with a central opening (101). The bottom of the central opening (101) is provided with a slightly concave positioning boss. The toothed compression module includes a bidirectional meshing rack (2) disposed on the inner sides of the left shell (401) and the right shell (501) around the central opening (101). 01), the end region of the bidirectional meshing rack (201) is provided with a micro-arc transition structure. The bidirectional meshing rack (201) is used to mesh with each other and compress the earplug located in the central opening (101) when the left shell (401) and the right shell (501) are closed. The bidirectional meshing rack (201) has no less than 4 trapezoidal teeth distributed on one side. The tooth pitch between adjacent trapezoidal teeth is 2mm. The top and bottom surfaces of the trapezoidal teeth are designed with a height difference to form an inclination angle to generate axial guiding force. The trapezoidal teeth of the bidirectional meshing rack (201) are designed to optimize stress distribution and prevent the earplug from tearing during compression.

2. The earplug pre-treatment device of claim 1, wherein, The main shell is integrally molded from polypropylene material, and the flexural modulus of the polypropylene material is greater than or equal to 3000MPa.

3. The earplug pre-treatment device of claim 1, wherein, The width of the central opening (101) is 11 mm, and the edge of the central opening (101) is provided with a rounded corner with a radius of 0.5 mm for placing uncompressed earplugs with a diameter of 10 mm to 12 mm.

4. The earplug pretreatment device of claim 1, wherein, The bidirectional meshing rack (201) is designed such that the diameter of the earplug after compression is 3.0±0.1mm.

5. The earplug pretreatment device of claim 1, wherein, The surfaces of the left shell (401) and the right shell (501) are matte-finished with a surface roughness Ra of 3.2 μm.

6. The earplug pretreatment device according to claim 1, characterized in that, The weight of the main outer shell is less than 10g.

7. The earplug pretreatment device of claim 1, wherein The snap-fit ​​connection structure (301) is made of the same material as the main shell and features a double thin-wall design, allowing it to be repeatedly bent and folded without breaking.

8. A method of manufacturing an earplug pre-treatment device according to any one of claims 1 to 7, characterized in that, Includes the following steps: Polypropylene material is placed in an injection mold, the cavity shape of which matches the shape of the earplug pretreatment device; The polypropylene material is injection molded to form an integrated main body shell, including the left shell (401), the right shell (501), the snap-fit ​​connection structure (301), and the bidirectional meshing rack (201). The formed main body shell is subjected to a matte surface treatment to achieve a surface roughness Ra of 3.2 μm; as well as The quality of the formed main shell is inspected to ensure that the weight is less than 10g and that the bidirectional meshing rack (201) can achieve a diameter of 3.0±0.1mm after the earplug is compressed.

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