Petite sonnerie is a chiming complication that sounds the time by itself as the hours pass. It strikes the hours at the top of each hour and, at each quarter, only the number of quarters gone. Because it strikes fewer blows than a grande sonnerie, it needs less power.
How does a petite sonnerie work?
Stepped cams called snails set the number of blows. A rack reads each snail by resting its feeler on one of the steps. The step it lands on decides how many blows follow. A regulating flywheel keeps the blows at an even pace from the first to the last. At the first, second and third quarter, the watch sounds only how many quarters have passed, on the higher-pitched gong. Because it chimes without being asked, the wearer must be able to switch it off, for example at night.
Not to be confused with
A grande sonnerie sounds the hour again at every quarter. A petite sonnerie does not. It strikes fewer blows, and it is simpler because it is not built around a repeater mechanism. A minute repeater is different again. It chimes only when the wearer asks, usually by moving a slide on the left side of the case. A petite sonnerie goes off by itself every quarter hour and has no on-demand repeat. On modern sonnerie watches, petite and grande sonnerie are usually two settings on the same watch, and the wearer chooses between them.
Where it comes from
Petite sonnerie belongs to the passing-strike group of chiming complications. These sound the time on their own as the hours go by, rather than on request. In wristwatches the idea is recent. Sonnerie chiming in a wristwatch was long considered impossible. Wristwatches with a petite or grande sonnerie did not appear until the late twentieth century. Philippe Dufour was the first to fit sonnerie chiming into a wristwatch, in 1992.
Checked
