| 摘要 |
PROBLEM TO BE SOLVED: To prevent a canister and an air piston from falling down by increasing the pressing force of the canister and the air piston in response to an increase in pressure within an air chamber. SOLUTION: The inner diameter of the insertion fitting part 22A of a canister 22 is formed smaller than the inner diameter of a tube mounting part 22B, a pressure receiving part 24 is formed between the insertion fitting part 22A and the tube mounting part 22B, concurrently the inner diameter of the insertion fitting part 26A of an air piston 26 is formed smaller than the inner diameter of the tube mounting part 26B, and the pressure receiving part 28 is thereby formed between the insertion fitting part 26A and the tube mounting part 26B. By this constitution, when the pressure of an air chamber A is increased, the acceptance of the aforesaid increased air pressure by the pressure receiving parts 24 and 28, causes the canister 22 to be strongly pressed against a canister cap 21, and permits the air piston 26 to strongly press an air piston guide 25 by the pressure receiving part 28, so that air is thereby prevented from leaking because of falling down. |
