Flexible door automatic locking mechanism - secures leaf to ram except when in lowest position

摘要

The system is for doors opening automatically and secures each leaf firmly to its ram when lifting for opening, and for most of the time when lowering to ensure automatic closing under the action of ramps. When in the lowermost position the two are released from each other to allow negotiation of the door if the automatic opening system should fail. The mechanism securing ram and leaf together can be in the form of a locking ring with balls fitting in a throat on a locking pivot on the leaf under the action of a sliding locking ring. An unlocking thrust ring on the door frame releases them from each other when the ram is in the lowermost position, by stopping the locking ring.