| 摘要 |
PROBLEM TO BE SOLVED: To eliminate a fear of retaining water in a bottom of a bathtub to be formed by cutting out a position of the bottom in contact with a releasing air valve unit to form a drain port. SOLUTION: An FRP bathtub 5 is formed of a cavity formed between a male die 1 and a female die 2. Then, the die 2 is removed. An air valve 41 is raised by an operation of compressed air. The air is injected from between an oblique surface of a head 411 of the valve 41 and a conical valve seat 421 of a bush 42, and the bathtub 5 is released from the die 1. A part of a recessed portion 52 for a drain port of a bottom 51 of the bathtub 5 is cut out, and the drain port is formed. A diameter D1 of an air valve unit mounting hole 11 is smaller than an inner diameter D2 of the portion 52 for the port of the bottom 51 of the bathtub 5. And, since the part of the portion 52 is cut out to form the port at the bathtub 5, there is no protrusion and recess part to retain water after the bottom of the bathtub 5 is drained. It is constituted that the water is not retained at the bottom of the bathtub 5 after the draining. |
