Patent ID: 8490650

Claim:
A coupler comprising a socket having a valve and energizing means for energizing the valve in a closing direction, and a plug having a valve and energizing means for energizing the valve of the plug in a closing direction, said plug being detachably fitted and coupled with the socket and being capable of communicating with the socket by opening the valve of the plug and the valve of the socket in the fitted and coupled state, wherein a key groove or a key is provided in one of the socket and the plug, and a ring member having a key or a key groove which can be fitted with the key groove or the key is provided in the other of the socket and the plug, said ring member being rotatable about a central axis of connection of the socket and the plug wherein the ring member is divided in a plurality of portions in the circumferential direction and is provided with elastic connecting means for connecting and holding the divided portions of the ring member.