A safety locking coupling assembly in which pull rings on the female coupling unit of a male coupling unit/female coupling unit assembly serve both to release the coupling assembly and to maintain the coupling assembly locked against unintentional disconnection. The pull rings are attached to cam arms which engage the male coupling unit to lock the coupling assembly and are disengaged from the male coupling unit to release the coupling assembly. In the locked condition of the coupling assembly, the pull rings abut against ears on the housing of the female coupling unit to oppose unintended movement of the cam arms from the locked position of the cam arms to the released position of the cam arms. Upon intentional removal of the pull rings from abutment with ears by an operator and pulling on the pull rings, the cam arms can be moved from the locked position of the cam arms to the released position of the cam arms to disconnect the coupling assembly.