| 摘要 |
PROBLEM TO BE SOLVED: To provide a film whistle which can produce stable sounds regardless of atmospheric temperatures and humidity and can produce the sounds of different octaves. SOLUTION: Arcuate vibration portions 2a to 2d varying in the radii of curvature from each other are formed at a plurality of points along the edge of a synthetic resin film 1. COPYRIGHT: (C)2004,JPO
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