Wall Device to Throw Off Enemy Scaling Ladders
A pivoted hinged gallery on a fortress wall, worked by ropes, to repel besiegers' ladders
The sheet depicts a defensive apparatus mounted on a fortress wall: a large hinged, pivoting structure that soldiers below work with ropes to hurl back scaling ladders, with detail views of the lever's pivot socket and a toothed bar. One note explains how the pivot of the lever must be anchored in the wall. Another warns that the beam on which the ladders would rest should be hidden in a channel in the wall, so enemies cannot lean their lower ladders on it and cut it away with axes.
On this page
Pivoting wall gallery to repel scaling ladders
A large hinged frame projects from the crenellated wall and is swung by soldiers hauling on ropes below. A note cautions that the beam on which attackers' ladders would rest must stay hidden in a groove in the wall, so the enemy cannot brace their lower ladders against it and cut it with axes.
Anchored pivot of the lever
Detail studies at the upper right and lower right show how the pivot, or fulcrum, of the lever is to be fixed into the masonry. The accompanying note specifies that the lever's balance-point must be secured in the wall in this manner.