Timeline / The oscillating pinion
The oscillating pinion
Invention
In 1887 Édouard Heuer patented a tilting pinion that couples the chronograph to the going train when you press start and uncouples it when you press stop; it is still the coupling in most chronographs made today.
- The need
- A chronograph has to connect its seconds hand to the running train the instant the start button is pressed, and disconnect it just as cleanly, without jolting the hand or the balance.
- Made by
- Édouard Heuer, Bienne. Patented in Germany on 6 February 1887 and in France on 3 May 1887; the United States patent, no. 377,896 of 14 February 1888, records both dates.
- What was new
- A small pinion with two sets of teeth on one arbor, mounted so that it can tilt. One end runs permanently with the fourth wheel; pressing start tilts the other end into mesh with the chronograph wheel, and pressing stop tilts it out. It replaced the horizontal coupling of the earlier clutch with something cheaper, quicker and kinder to the hands.
- Worth knowing
- Switzerland had no federal patent law until 1888, so Heuer protected the idea in Berlin and Paris; he was among the first Swiss filers when the law came in. The coupling is in the Valjoux 7750 and in TAG Heuer’s own calibres, so it is in more chronographs than any other device.
- Where it is now
- In production. The patents are on Google Patents and Espacenet.
Historian’s noteThe house phrase “patented the oscillating pinion” is fair; the US patent is titled simply “Stop-watch”, and the claims cover the engaging and disengaging mechanism. Business Montres has questioned whether the idea was entirely Heuer’s; the 1887 patents are the earliest record. See the page on Édouard Heuer and the chronograph.
SourcesUS patent 377,896 · Dictionnaire historique de la Suisse · Swiss Federal Institute of Intellectual Property, the first Swiss patent
Suggest a correction