Leonardo da Vinci’s ball-bearing concept used rolling balls to reduce friction between moving surfaces.
Leonardo drew a ball-bearing mechanism in the Codex Arundel, dating from around 1500. The design placed balls between rings so that the surfaces could move with rolling contact instead of sliding directly against one another. Reducing sliding friction was important for machines with rotating shafts and moving supports.
Leonardo’s drawing is often credited as an early ball-bearing design, but it was not a modern sealed bearing. His arrangement also showed a major problem: the balls could bunch together and create friction. Later bearing designs added cages or retainers to keep the rolling elements separated. Modern bearings became practical through later advances in manufacturing and materials.