BALL PLUNGER MECHANISM AND INNER MASK EQUIPPED WITH THE MECHANISM

摘要

PROBLEM TO BE SOLVED: To permit stable attachment to and detachment from an object and to prevent the life of a ball from shortening. SOLUTION: The ball plunger mechanism 11 is equipped with the ball 69 which is pressed to the object D, a ball housing hole 64 in which the ball 69 is put, a narrow part 68 formed at the opening end part of the ball housing hole 64, and a spring member 71 which presses the ball 69 against the narrow part 68. Part of the ball 69 projects outward from an opening 72 for ball projection formed of the narrow part 68. The hole diameter of the ball housing hole 64 is set to a value which is much larger than the diameter of the ball 69 so that the ball 69 which moves in the ball housing hole 64 does not come into contact with the internal wall of the ball housing hole 64 when the ball plunger mechanism 11 is in operation.