Spring detent escapement (marine chronometer)
Escape de detente de resorte (cronómetro marino)
- Date
- 1748 (Le Roy); c. 1780 (Earnshaw) · confidence medium
- Place
- London, England, United Kingdom
- Credited to
- Pierre Le Roy; John Arnold; Thomas Earnshaw
- Field
- Movement
⚠️ Disputed: the sources disagree.
What it is
An escapement that gives a single impulse per oscillation and barely touches the balance, so rate hardly depends on oil. Earnshaw's spring-detent version was simple and robust and became the standard in chronometers.
The priority between John Arnold and Thomas Earnshaw was a famous dispute; both built on Pierre Le Roy's pivoted detent (1748).
What it led to
- chronometers that could be made in numbers for the navy
- routine longitude determination at sea
- precision watches into the 20th century