Clock spring equalizer. Da vinci drawing represents one of a number of suggested improvement to the fusee. The drawing is one of at least three very similar attempts to design a conical equalizing device directly geared to the spring which is contained in the barrel which forms the base of the mechanism. As the pinion climbs the slowly revolving cone of gear teeth, its axle slides up the spring axis and the vertical shaft on the left. Thus the power of the spring, as applied to the long lantern gear near the top of the vertical shaft, is keep constant. Above main drawing is a section of the pinion and its fixed but sliding axle. Leonardo di ser Piero da Vinci (April 15, 1452 - May 2, 1519) was an Italian Renaissance polymath: painter, sculptor, architect, musician, mathematician, engineer, inventor, anatomist, geologist, cartographer, botanist, and writer. He has often been described as the archetype of the Renaissance Man ,one of the greatest painters of all time and perhaps the most diversely talented person ever to have lived.