To prevent the applying of the unnecessary stress while enabling the expansion of a seal tube to the same shape even in the case of repeating expansion and shrinkage of the seal tube.
A ring-like seal tube 22 is fitted on a peripheral surface of a plug body 3 to be inserted into a nozzle 2 of a water holding container, and the seal tube 22 is expanded and shrunken by filling or discharging air. The seal tube 22 is formed thick at an outer peripheral wall part 22a and an inner peripheral wall part 22b, and both side wall parts 22c are formed thinner than the outer peripheral wall part 22a and the inner peripheral wall part 22b. The seal tube 22 is deformed for expansion and shrinkage by, flexibility of both the side wall parts 22c, and expanded to a constant shape so that the outer peripheral wall part 22a becomes easy to be tightly fitted to the inner surface of the nozzle 2.
| JP5722837 | Bag for water stop device |
INOUE KEN
NOZAWA YUKIHIRO
ISHII TAKASHI
