The pole hammer is very useful for driving poles into the ground. It is used in the building of pound locks and banks, ad it is very common in Leonardo's time. He describes it in a sheet dedicated to projects deviating the course of the Arno river.
It is made up of a winch that lifts weights hooked with a double leaf spring system. The leaf springs are unhooked at the maximum height to transmit to the pile all the available force. This operation can be repeated several times, until the pile is driven into the ground at the required depth.
Codex Atlanticus, sheet 785 b