A locking device for a connector assembly wherein a completely fitted or locked condition of connectors thereof can be confirmed clearly at a glance by way of an electric circuit. One of the connectors to be fitted with each other by the above locking device is provided with a locking plate for movement...http://www.google.com/patents/US4878853?utm_source=gb-gplus-sharePatent US4878853 - Locking device for connector assembly
