US Patent 9879809 Coupling with safety valve function

A coupling which can enhance safety will be provided, when the coupling, a hose, and the like are exposed to high pressure for some reasons or other while in use, by leaking the high pressure fluid to the outside to open a sealing portion of the coupling at a stage where the coupling condition between the couplings is maintained, and decreases the pressure. Further, the coupling can warn the operator or the like of the abnormality by ejecting a fluid from a leak path or a fluid ejection port.