Baffled Earplug Pocket for Noise Attenuation
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Solution Overview
Problem
Existing earplugs lack effective noise attenuation characteristics while being easy to insert and comfortable, and are often costly to produce.
Innovation Solution
An earplug with a molded outer surface and internal pocket featuring a plurality of baffles that break up the pocket walls, formed using a core pin with slots during injection molding, allowing the core pin to be removed post-molding, and a rear pocket blocker to prevent sound passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an earplug is made with a simple hollow body structure, then it is easy to manufacture and insert, but it provides poor noise attenuation
Solution Approach 1:
The internal pocket space is segmented into multiple compartments by introducing baffles (annular ribs) that divide the hollow body into separate chambers. This segmentation creates a more complex acoustic environment within the earplug, improving noise attenuation by 2 to 5 dB across various frequencies while maintaining the basic hollow body structure for ease of manufacture
Solution Approach 2:
Baffles are strategically positioned at specific locations within the pocket (such as at the front, middle, and rear sections) to create localized acoustic barriers. The baffles have varying dimensions and positions tailored to specific frequency ranges, providing enhanced noise attenuation at critical locations while maintaining overall structural simplicity
2Object-affected harmful factors
If baffles are added to the pocket to improve noise blocking, then sound attenuation increases, but manufacturing complexity increases
Solution Approach 1:
Multiple baffles are merged into a single integrated component that forms one continuous structure within the pocket. This unified baffle assembly reduces the number of separate parts that need to be manufactured and assembled, simplifying the manufacturing process while still providing effective noise blocking through the combined effect of multiple baffled chambers
Solution Approach 2:
The baffles serve multiple functions simultaneously: they act as acoustic barriers to block sound transmission, provide structural support to maintain pocket shape, and create turbulence in the trapped gas to enhance damping. This multi-functionality reduces the need for additional components, keeping the overall device complexity low
3Object-affected harmful factors
If the pocket is fully sealed to block sound, then noise attenuation improves, but ease of insertion decreases due to increased rigidity
Solution Approach 1:
Instead of completely sealing the pocket, the design uses partial sealing through baffles that block approximately 50-70% of the cross-sectional area at each location. This partial blocking provides sufficient noise attenuation (2-5 dB improvement) while leaving enough open space to maintain the pocket's compressibility and flexibility for easy insertion and comfortable wear
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The earplug achieves enhanced noise blocking with improved comfort and reduced production costs, with baffle design increasing sound attenuation by 2 to 5 dB across various frequencies.
Implementation Method 1
One type of earplug is formed primarily of elastomeric material and has a pocket containing gas (air) that enables the earplug to be more easily compressed during insertion and to remain compressed in the ear
Implementation Method 2
The baffles each blocks at least about half of the cross section of the pocket as seen when looking along the earplug axis... When the earplug is compressed in the ear, the baffles each can block almost the entire cross section of the pocket
Data Source
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AI summary
An earplug (10) with a body front portion (22) for insertion into a person's ear canal, has a pocket (30) to increase comfort and is constructed to enhance noise attenuation. The pocket, which allows easier compression of the body front portion for increased comfort, has a plurality of baffles (50) that attenuate sound better than a pocket without baffles. The pocket with baffles is formed by a core pin (80) that lies in an injection mold (82) and that forms the pocket, the core pin having a plurality of slots (81) that form the baffles. The pocket includes a rear portion (36) that forms a wide passage, and the earplug includes a blocker portion (90) that partially or completely closes off the rear pocket passage.