PROBLEM TO BE SOLVED: To prevent soiling of the periphery of an overflow port and a wall surface of a bathtub by enabling an outer shape of the bathtub to be designed without giving consideration to an extra size of a parapet structure, when the outer shape of the bathtub is designed.SOLUTION: A concave groove having a parapet structure is installed on a horizontal line of a wall surface of an upper part of a bathtub in such a manner that an opening of the concave groove is positioned inside the bathtub. Thus, structurally, an upper edge of the bathtub does not jut inward. A drain outlet in the concave groove, which has a water level adjusting mechanism for securing a fixed distance between a surface of water stored in the bathtub and the parapet structure, is provided on the side surface or undersurface of the concave groove.COPYRIGHT: (C)2014,JPO&INPIT【課題】浴槽外形を設計する時、波返し構造の余分な大きさを考慮せず設計できるようにし、オーバーフロー口の周囲や浴槽壁面が汚れないようにする。【解決手段】波返し構造を有する凹型溝を、当該浴槽の上部の壁面の水平線上に、前記凹型溝の開口が前記浴槽の内方となるよう設置することで、前記浴槽の上縁部を内方にせり出さない構造とし、浴槽に溜めた水面と前記波返し構造との距離を一定に確保するための水位調整機能を有する凹型溝内排水口を、前記凹型溝の側面または下面に設ける。【選択図】図1
