Variable Cross-Section Gong for Harmonic Tuning
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Solution Overview
Problem
Existing striking mechanisms in horological movements, such as those in watches with minute repeaters and alarms, fail to produce a harmonically tuned sound due to partial multiples of the fundamental frequency, leading to inconsistent pitch perception across users and imprecise inter-gong tuning.
Innovation Solution
A gong design with varying cross-sectional size and shape along its length, optimized using finite-element simulation tools, to produce strictly harmonic components within a desired frequency range, ensuring consistent pitch and inter-gong tuning by creating dominant partials and harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional gong with uniform cross-section is used, then the manufacturing process is simple, but the sound emitted has inconsistent pitch perception and lacks harmonic tuning
Solution Approach 1:
The gong employs a variable cross-sectional geometry where the cross-sectional area changes along the longitudinal axis. Specifically, the cross-section is larger at the free end and smaller near the heel, creating local variations in mass distribution that generate harmonic partials. This local quality variation resolves the pitch consistency issue while maintaining manufacturing feasibility through controlled geometry changes.
Solution Approach 2:
The invention changes the geometric parameters of the gong by varying the cross-sectional area along the length. The cross-sectional dimension is deliberately designed to increase from the heel toward the free end, which fundamentally alters the vibrational characteristics to produce strictly harmonic components, thereby achieving precise pitch perception.
2Manufacturing precision
If a gong with variable cross-section is designed to achieve harmonic tuning, then pitch consistency improves, but manufacturing complexity increases
Solution Approach 1:
The variable cross-sectional design creates specific local mass distributions that are optimized for harmonic vibration. The cross-sectional area is deliberately varied along the longitudinal axis to generate the desired harmonic spectrum, achieving precise inter-gong tuning while the geometry remains manufacturable through controlled shaping techniques.
3Reliability
If traditional gong materials and geometries are used, then the structure is simple, but the vibratory transmission quality is insufficient
Solution Approach 1:
The gong's geometric parameters are optimized to enhance vibratory transmission. The variable cross-section design creates favorable mass distribution that improves the transmission of vibrations from the hammer to the gong and from the gong to the heel, thereby enhancing overall vibratory transmission quality without requiring complex interface mechanisms.
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 gong emits a subjectively consistent sound with precise pitch and inter-gong tuning, with each partial within 5 cents of the target frequency, enhancing the perceived quality and homogeneity of the sound emitted.
Implementation Method 1
The gong (or gongs) realizes the frequency selection function by vibrating at a range of frequencies among which the audible ones will tune the emitted sound to a certain perceived pitch level
Implementation Method 2
The vibratory transmission function is realized by materials selection, geometries, and by the design of the interfaces between the gong or gongs, their heels, and the element of the watch movement or case to which the heel or heels are fastened
Implementation Method 3
the acoustic radiation function is realized by the part or parts of the watch case, generally the back or crystal, which convert the parietal vibrations to the ambient air as audible acoustic pressures
Data Source
AI summary
A gong for a striking mechanism in a horological movement comprises a first end mounted to a heel and a second end that is free. The first end and the second end define a longitudinal axis along the length of the gong, wherein the gong has a cross-section size that is variable along all or part of its longitudinal axis including an end section of the gong that comprises the free end.