Worm screw on rack

Within a wooden frame, a worm screw is mounted between two pivots, engaging a circular section of rack connected to a fixed rod. The worm screw transmits its motion to the rack, thus producing the alternating movement of the rod, which can in turn be linked to other moving parts.

This mechanism, reconstructed on the basis of a drawing from Manuscript B of the Institut de France in Paris, recalls the operation of modern automobile steering systems.

Leonardo was always fascinated by the structure of the screw, which he studied and depicted in all its possible variations, later classifying their individual features in numerous pages of his manuscripts. Through extensive graphic documentation, he illustrated the many potential applications of this element in machines and mechanical operations.