TOILET-BOWL FLUSHING WATER TANK DEVICE

PROBLEM TO BE SOLVED: To provide a toilet-bowl flushing water tank device which is equipped with a float member exerting buoyancy for keeping a drain valve opened in the state of being sunk in flushing water, and which enables a lower-limit position of a height position of a float to be adjusted to be as low as possible. SOLUTION: This toilet-bowl flushing water tank device 100 comprises: a flushing water tank 10 for storing the flushing water for being supplied to the toilet bowl; a drain outlet 37 which is arranged in the bottom 10a of the flushing water tank 10, so as to discharge the flushing water toward the toilet bowl; the drain valve 34 which is equipped with a sealing surface 34a seating itself on the drain outlet 37, so as to open/close the drain outlet 37; a cord-like pull-up member 33 which is connected to a top surface of the drain valve 34, so as to pull up the drain valve 34; and the float 35 which exerts the buoyancy for keeping the drain valve 34 opened in the state of being sunk in the flushing water. Characteristically, the float 35 can be fixed to a midway portion of the pull-up member 33, and the drain valve 34 is provided with a float arrangement portion 41 which can keep an undersurface 35b of the float 35 in a position lower than the sealing surface 34a. COPYRIGHT: (C)2008,JPO&INPIT