Adolphe Nicole was granted a patent for a mechanism to reset the second hand of the stopwatch to zero (setting the second hand to "0" at 12 o'clock). The major element of this mechanism is so-called zero-reset heart cam. The solution with the heart cam since its invention is still used in most mechanical stopwatches.
However, only 18 years after the patent was granted, in 1862 Adolphe Nicole presented a solution working in the watch. It was a pocket watch, which had all three basic stopwatch functions: start, stop and reset. The heart cam was also used in the solution of the stopwatch with the rattrapante hands.
Notifier: Władysław Meller
Other records: Timeline of Watchmaking Innovations