Continental Europe, adopted widely in England · Documented from the 16th century; refined stopwork forms common by the 17th–18th centuries
Fusee Stopwork (Maintaining Power and Overwind Prevention)
Needs researchA small but essential piece of fusee-watch and fusee-clock engineering that prevented damage to the mainspring and chain, and is a useful dating/quality indicator when examining a movement.
Stopwork limits the number of turns the fusee can take, preventing the chain or gut line from being wound off the cone or overtightened against the barrel, and typically uses a pair of shaped plates ('Geneva stop'-like blocking work is a related but distinct device, see the Geneva stop entry) or a simple pinned-wheel arrangement.
Because stopwork is a shop-floor mechanical solution rather than a single patented invention, there is no founding patent to cite; its history is documented through surviving movements rather than filings.
How to verify this yourself
There is no patent office record to search for stopwork generally; consult movement-survey literature and museum catalogues (e.g. British Museum, Science Museum Group) for dated examples instead.
Manufacturers known to have used it
- English and Continental fusee-clock and fusee-watch makers generally
Sources & references
- Britten, F. J., Old Clocks and Watches and Their Makers
- Science Museum Group collection notes on fusee movements
Where sources disagree, the disagreement is stated rather than resolved silently.