Alarm Sound Apparatus Reflecting Wall Resonance
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Solution Overview
Problem
Conventional trumpet horns have limitations in sound pressure level due to the design of their resonance pipes and covers, which allow foreign matter entry while failing to optimize sound wave reflection and resonance.
Innovation Solution
An alarm sound generating apparatus with a coil, fixed core, movable core, diaphragm, and acoustic pipe, where the distance between the acoustic pipe outlet and a reflecting wall is optimized to ±10% of an odd multiple of one-fourth of the wavelength of the alarm sound's fundamental frequency, positioning a node at the reflecting wall to enhance sound wave reflection and resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cover is added to prevent foreign matter entry, then reliability is improved, but sound pressure level deteriorates due to poor sound wave reflection
Solution Approach 1:
The patent changes the geometric parameter of the cover by adding a reflecting wall at a specific distance (odd multiple of one-fourth wavelength) from the acoustic pipe outlet. This parameter optimization enables the cover to simultaneously prevent foreign matter entry and enhance sound wave reflection, resolving the contradiction between reliability and sound pressure level.
2Device complexity
If the resonance pipe is designed with a simple cover, then device complexity is reduced, but sound wave reflection and resonance are not optimized
Solution Approach 1:
The patent introduces a reflecting wall with optimized distance parameter (odd multiple of one-fourth wavelength) to enhance sound wave reflection without significantly increasing structural complexity. This resolves the contradiction between device simplicity and acoustic performance optimization.
3Ease of manufacture
If the distance between acoustic pipe outlet and reflecting wall is not optimized, then manufacturing is simpler, but sound wave attenuation increases
Solution Approach 1:
The patent specifies the distance parameter as an odd multiple of one-fourth wavelength, which creates a standing wave pattern with a node at the reflecting wall. This parameter optimization minimizes sound wave attenuation while maintaining manufacturability, resolving the contradiction between ease of manufacture and energy loss.
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
This configuration increases sound pressure by minimizing wave attenuation, allowing for a higher quality and more intense alarm sound release while preventing foreign matter entry.
Implementation Method 1
The coil generates magnetic force when energized and the fixed core generates magnetic attraction force by the magnetic force generated by the coil
Implementation Method 2
The diaphragm is fixed to the movable core and configured to generate sound waves by oscillating in accordance with movements of the movable core
Implementation Method 3
The reflecting wall is configured to reflect the sound waves
Implementation Method 4
A distance between the outlet end of the acoustic pipe and the reflecting wall falls within ±10% of an odd multiple of one-fourth of a wavelength calculated from a fundamental frequency of the alarm sound
Data Source
AI summary
An alarm sound generating apparatus includes a spiral pipe extending from a sound wave inlet to a sound wave outlet, and a cover including a reflecting wall configured to reflect a sound wave released from the sound wave outlet. The reflecting wall is distanced from and faces to the sound wave outlet. A distance between the sound wave outlet and the reflecting wall falls within ±10% of an odd multiple of one-fourth of a wavelength calculated from a fundamental frequency of the alarm sound or a multiple harmonic thereof.