Connection tube detachment prevention structure and detachment prevention device used therefor

摘要

PROBLEM TO BE SOLVED: To provide a detachment prevention tool which is: reasonably down-sized while maintaining high detachment-preventing performance, while simplifying a structure of the detachment prevention tool, and reducing manufacturing cost; and easily attachable while avoiding an object present on a part of a whole circumference of a connection part.SOLUTION: A detachment prevention tool B includes: an annular fastening body 10 of block dividing structure that is fastened to an inserting tube 2 connected to a receiving tube part 1; and an engagement body 11 which is extended from a plurality of portions in a circumferential direction, of the annular fastening body via the outer side of a push ring 4 so as to be integrally formed and is engageable to an engaged portion 1A of the receiving pipe part 1. Only an engagement body 11 located at a center side portion in a circumferential direction, of each fastening body 10A of block dividing structure, is arranged at a position where an intermediate part 11b of the engagement body 11 is overlapped with an operation part 6A of a retaining means A provided to the push ring 4 in a tube radial direction, and a through hole 17 or a recess into which the operation part 6A of the retaining means A is inserted is formed in the intermediate part 11b of the engagement body 11 arranged in the overlapping manner.