Coupling security and safety latch system

Abstract From the Canadian patent

A security and safety latch system for fluid couplings particularly for fluid couplings utilizing rotatable valves wherein connection and disconnection of the coupling parts is by relative rotation of the parts and the valves are rotated between open and closed positions by exterior manually operated handles. The coupling parts and the valve handles are provided with interfering surfaces which prevent the parts from being relatively rotated and disconnected until both coupling valves are closed. Further the valve handles, are provided with security latches which permit the handles to be locked in the closed position, and prevent the valve handles from being locked in the valve open position.