PROBLEM TO BE SOLVED: To provide the drainage mechanism of a water tank that has no concern for water leakage regardless of the cross-section area of the opening part of the water tank and is so compact as not to obstruct inside appreciation. SOLUTION: The drainage mechanism has female bulb sockets (2A and 2B) and a male bulb socket (5). The female bulb sockets (2A and 2B) are arranged at an opening part (13) formed in the vicinity of the undersurface (11) or the side (12) of the water tank and a female screw part (2t) is formed to make a hollow shape. Ring-shaped members (31 an 32 and 4) are fastened to the outer peripheral part (22) of the female screw part (2t), the cross-section areas of the ring-shaped members (32 and 4) are set to be sufficiently larger than the opening part (13) of the water tank. The bottoms of the ring-shaped members (32 and 4) are fastened so as to cover the opening part (13). The male screw part (5t) of the male bulb socket (5) arranged at the outside of the water tank is screwed to the female screw part (2t) of the female bulb sockets (2A and 2B). COPYRIGHT: (C)2007,JPO&INPIT
