To prevent the falling of an external facing plate installed to a sound insulation wall by a simple means.
A notch 2a is formed to one of projecting sections 2 at positions opposed to adjacent each side end section of the two external facing plates 1 while holes 2b are formed to each projecting section 2, mounting pieces 6 and 7 are fitted into each projecting section 2 from the notch 2a, the front end side of the connecting section 8 of the first mounting piece 6 is stretched and superposed to the second mounting piece 7, the through-holes 9 of each mounting piece 6 and 7 and the holes 12a and 12b of the connecting section 8 of the first mounting piece 6 are conformed to each other at the positions of the holes 2b of each projecting section 2, and bolts 10 are inserted from the holes 12a and 12b of the connecting section 8 respectively, and screw- connected to nuts 11 mounted on the rear sides of each mounting piece 6 and 7, thus simply connecting the two external facing plates 1 under the state in which the outer casings 1 are secured to the sound insulation wall, then preventing the falling of the outer casings 1.
YANAI HIROYUKI
KIMURA SHINZO
OKADA MITSUHIRO
HINO SHINJIRO
JAPAN HIGHWAY PUBLIC CORP