PURPOSE: To efficiently manufacture a wooden bathtub having roundness at four corners by forming a joint member into an arcuate pillar body by butt- joining a plurality of unit members having each joint edge surface which is formed by cutting the edge surface of a basic member, at a proper angle.
CONSTITUTION: A plurality of first unit members 52 having each joint edge surface which is formed by cutting the edge surface 53 of a basic member are prepared, and a prescribed number of first unit members 52 are arranged so that the contiguous edge surface 53 are opposed. The first unit members 52 are butt-joined at a proper angle, and a hollow cylinder 51' is formed. Joint members 32, 34, 36, and 38 are formed by cutting said hollow cylinder 51' into four parts in the circumferential direction. Further, a plurality of second unit member 72 having the opposed edge surfaces 74 and 76 are prepared, and the side wall members 22, 24, 26, and 28 are formed by joint-attaching the joint edge surfaces 74 and 76 of the second unit members 72. A side trunk 12 is formed by butt-joining these joint members and the side wall members, and a bottom plate 14 is fixed onto the bottom part of the side trunk 12.
AMINO TAMOTSU
TOMA TAKESHI
