US Patent 9528649 Female joint having safety function

A female coupling member includes a coupling member body having a fluid passage and being configured to receive a male coupling member from a front end thereof, and a valve member disposed in the coupling member body to traverse the fluid passage. The valve member has an opening and is displaceable between an open position and a closed position. In the open position, the valve member communicates between a front end side and a rear end side of the fluid passage through the opening. In the closed position, the opening is located outside the fluid passage to close communication between the front end side and the rear end side of the fluid passage. The valve member has a purge passage configured to communicate with both the front end side of the fluid passage and the atmosphere outside the female coupling member when the valve member is in the closed position.