Mechanical Door Locks for Access Control
Once power to a machine has been isolated and the ‘Isolation Key’ has been exchanged for the ‘Access Keys’, the final sequence of a trapped key interlocking system involves using the ‘Access Key’s, that were released from the key exchange unit, to unlock the mechanical door locks holding each of the machine's guard doors closed. A mechanical door lock is unlocked by inserting and trapping the correctly coded ‘Access Key’, enabling the mechanical door locks actuator to be released to now permit access inside the hazardous area.
By using mechanical door locks to control access into hazardous machine areas, this completely eliminates the need to run copious amount of cabling to each of the guard doors that would be required for electrical interlocking devices such as safety gate switches. As there are no wiring requirements for safeguarding a machine's access points, trapped key interlocking systems can be installed in a much faster timeframe than any other form of safety interlocking devices.
For added protection and personnel security, it is recommended that a double door lock system is used which enables the removal of a ‘Safety Key’ after the mechanical door lock has been unlocked. This key should remain on the operators person while they work inside of the machine to prevent the risk of unexpected machine restart.