Automatically extending fire ladder - has pivoting arm at base of building which grips lower rung to tension ladder

摘要

The automatically descending and extending fire ladder is normally stored in a wall recess (2) at the top of a tall building, and is dropped down the facade in the event of a fire. The ladder longerons (1) are of chain construction and an automatic tensioning mechanism (6) engages a lower rung (10) to tension the longerons. The tensioning mechanism may be a bottom hung door (6) to a recess (16) in the base of the building wall. The door has a grappling hook (9) on the top edge, has a width of approx. one third of that of the ladder, and is sprung to pivot out (11) when a bolt releases a cogged wheel segment on the back of the door, and prevented from returning by a ratchet.