Petite sonnerie
Strikes the hours automatically as they pass
What it is
The petite sonnerie (small strike) automatically strikes the hours as they pass but is silent at the quarter-hours. At 3:45 it does nothing; at 4:00 it strikes four low tones. It uses a dedicated striking mainspring and train, like the grande sonnerie, but the strike train fires only twelve times per day (once per hour) rather than at every quarter-hour. The petite sonnerie is almost always paired with a minute repeater on the same movement, so on-demand precision is available even when automatic striking is set to petite or silent mode.
History
Petite sonnerie watches were made alongside grande sonnerie pieces from the 17th century onward. The distinction mattered practically: grande sonnerie drains the striking mainspring roughly four times faster than petite sonnerie because it fires at every quarter. Modern grande sonnerie wristwatches; the Patek Philippe Grand Complications, AP Grande Sonnerie; include a three-position mode switch: grande sonnerie (all quarters and hours automatically), petite sonnerie (hours only automatically), and silent (on-demand repeating only). This switch allows the wearer to conserve the striking mainspring when extended automatic striking is not needed.
How it works
The automatic strike mechanism fires once at each full hour, striking the hour count on the low gong. Quarter-hours pass without the strike train firing. A silence lever or mode switch on the case side disengages the automatic striking train without affecting the going train or the on-demand repeating mechanism. Only one gong and hammer pair is strictly required for hours-only striking, though most petite sonnerie movements carry two gongs for tonal compatibility with the minute repeater on the same caliber.
Parts required
Striking mainspring and barrel, hour-release lever driven by 12-hour cam, silence mechanism, gong and hammer (one pair minimum for hours-only; typically two gongs for tonal consistency with the paired minute repeater)
In the catalog
Related
- Grande sonnerie: Strikes the time automatically as it passes; the most demanding audible
- Minute repeater: Strikes the time in chimes on demand
- Quarter repeater: Chimes hours and quarter-hours on demand
