The SMF bunker doors have a COMECER electro-mechanical operating system, which includes two steel wheels sliding and rolling on suspended wall guides and a moving system with gearmotor-pinion-rack.
The gearmotor is self-locking and maintains the bunker door in a closed position during normal working conditions.
The SMF bunker door can be manually unblocked thanks to the electro-magnetic joint inserted between the gearmotor and the pinion, if the emergency button is pressed or when there is no electricity supply.