| 摘要 |
PURPOSE:To simplify the structure of a back case by fixing a casing ring used as a vibrating plate attached to the back on a middle. CONSTITUTION:A casing ring 6 is provided with a corn shaped projection part 6a and a gap S between the casing ring and a back 2 and welded with the back case 2. The position surrounded by the rising part 6a of the casing ring 6, the external circumference of the back case 2a and the lower stage part of a middle 3 are filled with packing 5. Water-proof is made available by interlocking and fixing between the biting convex of the casing ring 6 and the biting concave of the body 3. The back 2 is provided with a sound releasing hole 2c, which displays a function as the vibrating plate of the casing ring 6. |
