What Leonardo da Vinci invention automatically wound thread onto a spool?

Leonardo da Vinci’s automatic bobbin winder was designed to wind thread onto a spool automatically.

The machine belongs to Leonardo’s studies of textile production and labor-saving mechanisms. Its purpose was to guide thread evenly onto a bobbin, reducing repetitive manual work and producing a more regular winding pattern. The design combines rotating parts with a guide mechanism that moves the thread across the spool.

Leonardo’s notebooks contain many machines for manufacturing, and historians must distinguish drawn mechanisms from devices that were actually built. The bobbin winder is best understood as a design for improving textile preparation, not as the documented origin of every later spinning machine.

It is also easy to confuse the device with the spinning jenny. A bobbin winder prepares thread on a bobbin; a spinning machine makes or twists thread. Those are related textile operations, but they are not the same function.