Pile driver with ratchet winch

Before concrete foundations, most bridges and sea walls were built on wooden piles sunk underwater. Several inventions sought to mechanise this operation, which demanded both power and precision. Machines for sinking piles comprised a block of wood or metal sliding between two vertical guide rails. The block is raised with a winch or rope then allowed to fall on the pile. This model, formerly in the Institut de France and made with great precision, has a lever that works a ratchet wheel that reduces the physical effort required to raise the block. It was very probably used to test the machine’s kinematics, particularly the working of the winch brake, an innovation that accelerates the raising of the block by limiting the unwinding of the rope each time the block falls.