Abstract: The present invention provides a safety interlock system for mechanically securing an industrial process or appliance, including a lock which can be unlocked with a key, wherein the key comprises one or more key code elements which can be positioned in different positions and the selected position of the key code elements corresponds with a specific key code, and wherein the lock comprises one or more lock code elements which can be positioned in different positions and the selected position corresponds with a specific lock code, wherein the lock is locked except when the key code is identical to the lock code when the key is inserted.