To easily remove a connecting pipe which is inserted into a coupling main body and is prevented from falling by a fall-off prevention ring from a coupling main body.
A groove part 11b for fall-off prevention is provided throughout the entire periphery on the inner peripheral surface of the tip part adjacently to the opening end face of a coupling main body 11 and a fall-off prevention ring 13 is fitted into this groove part 11b for fall-off prevention. The fall-off prevention ring 13 is constituted to be smaller inside diameter than the outside diameter of a connecting pipe to be inserted into a coupling main body 11 so as to restrain on the outer peripheral surface of the connecting pipe by a C ring whose part of the peripheral direction is segmented. The groove part 11b for fall-off prevention which is provided on the coupling main body 11 leads to the outside from the opening end face and the outer peripheral surface of the coupling main body 11 via a window part 11d opening the end face and the outer peripheral surface of the coupling main body 11. The peripheral direction length of the window part 11d is made larger than a clearance of a segmented part of the fall-off prevention ring 13.
Kageyama, Hideki
Nagai, Takuo
Matsuru, Manitsushiyu
HITACHI METALS LTD