Safety Key in a Key Transfer System

DIN EN 14119:2003 specifically outlines key transfer systems as locking devices based on the transfer of a key between the key switch and key lock. The system is defined by the key, which is always retained in either the key switch or the key lock. This means the key is only released once the guard is securely closed and locked.

A combination of processes is possible, as illustrated in the diagram below. When the plant is stationary, the key is removed first, interrupting the safety circuit through positively driven contacts.
Using the red key, the operator can release two additional blue keys in a purely mechanical "key exchange box."
be accessed from behind. The blue key is inserted, unlocking the hatch. The key cannot be removed while the hatch is open.

A double lock with similar logic is used for the door that can be accessed from behind. In addition, the operator removes a safety key (green) and takes it into the plant for personal security. To start the plant, the entire procedure must be reversed. The keys are high-coded with more than 1000 codes in accordance with DIN EN 14119:2013.