| 摘要 |
PROBLEM TO BE SOLVED: To provide sound insulation for airborne sound and propagating sound generated by impacts and vibrations between lid bodies and side ditch blocks and also to eliminate noise by diffusion and emission. SOLUTION: The lid body is placed on a stepped portion A at the inner side of a side wall of the side ditch block 10; at the side edge portion of a lid body 20 linked to the stepped portion A of the side ditch block 10 (a lid receiving surface 12 of a horizontal surface shape and an erected lid dropping guide surface 13), noise elimination constructions 30 and 30' are provided, which comprise a plurality of flat-faced protrusions 33 for eliminating a rattling noise by decreasing a contact surface with the stepped portion A, a sound insulating wall 32 for shutting off the propagation of the sound generated between the portion A and the lid body 20 to the inside of the side ditch, and a vertical ditch 32 guiding the sound generated between the portion A and the lid body 20 to the outside of the side ditch. COPYRIGHT: (C)2004,JPO
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