Abstract: A platelike rib 7 moulded integrally with a front cabinet is linked via the leg pieces 61 with the boss 5. The rib 7 has a high strength portion 73 of increased thickness extending lengthways to be continuous to a rear end portion of the boss 5. A link portion of the rib 7 with an outer board 11 is formed over an entire length in smaller thickness than the high strength portion 73. The surface of the high strength portion 73 at a front end portion is formed like a concave curved face 75.

Abstract: A cabinet is formed by fitting a protruding portion 21 on a rear cabinet 2 side to an inner side of an edge portion 12 of an opening on a front cabinet 1 side. Convex portions 4 provided at a plurality of positions on the obverse surface of the protruding portion 21 form a gap between the obverse surface of the protruding portion 21 and the reverse surface of the edge portion 12 of the opening at the fitted portion. The top portion of each of the convex portion 4 is formed in a tapered or arcuate shape. The convex portion 4 may be formed of a pair of projections provided at two adjacent positions.