Sill-mounted lever latch for double door - uses bell-crank lever on axle through apex having axially offset legs and trapping door against stop

摘要

The automatic sill-mounted lever-latch secures a leaf of a double door against a door stop, both the stop (2) and the latch being mounted on a part embedded ground-anchored (4) base plate (1). As the leaf reaches the closure station it pivots a latch to trap the door between the stop and retaining bolt (7), a magnetic or a spring catch being used to secure the mechanism at closure. A horizontal axle (5) is mounted free to rotate within terminal end straps (6) being welded to a parallel bar from which two perpendicular radial arms (7, 9) project. The arms may be formed by cranking bar ends, and present an open 'L' section to the door approaching closure. A weak return spring may anchor the free end of the retaining bolt (7), and spring catches may use a serrated blade spring fork (10), engaging a fixed stud (11).