Lever spring of Benoit tourbillon

Ressort de l'ancre du Tourbillon de Benoit
Detached escapement invented by Achille Hubert Benoît (1804-1895) in 1855.
In this escapement, the energy is transmitted to the hairspring and not to the balance wheel. The neutral point of the hairspring is shifted with each oscillation, for this reason this escapement is also called “tourbillon”
Qualities of Benoit's tourbillon:
- High efficiency: up to 70%, i.e. approximately 2x higher than the efficiency of the Swiss lever escapement,
- The neutral point is moved at each oscillation period, which makes it possible to compensate for oscillator balancing faults,
- no tripping, knocking and overbanking problems
Faults of the Benoit's tourbillon:
- Bad isochronism: the period of oscillation of the oscillator varies with its amplitude, consequently with the winding level of the barrel.
- Requires a large amplitude for unlocking, therefore risk of stopping when the oscillation amplitude drops due to shock.
Because of these defects, the Benoit tourbillon is not used in practice.
Musique:
Titre: Saying Goodbye In The Rain
Auteur: Jelsonic
Source: jelsonic.com
Licence: creativecommon...
Téléchargement (3MB): auboutdufil.co...

[@patchkessler8020]

Beautiful model- bravo!! Do you know where I can learn more about AH Benoit?

[@kovacskovacs3465]

It's nice that the spring detent lever isn't hit twice like on some other designs where the spring gets hit with no impulse benefit (i.e. the detent is in the way on the return trip). Is the "mainspring" (in this case, the power via weight/gravity) for the power wrapped around the lever to provide the impulse to the balance wheel like on traditional Swiss lever escapements? Or is it wrapped around the balance wheel staff (in which case, that may be too much torque, while the spring lever is providing the power to only push the bottom lever up)? Given this setup with where the detent is, I'm thinking it's the latter or it wouldn't be any different from a conventional lever escapement, and there would be no need for the detent to be there to provide power as the weight already does that.

[@romanmechetnerful]

That's an interesting escapement, so there's no impulse on the balance but just the tension from the spring that gives it more twist ?

[@Waterpearl_escapement]

That's right, the energy pulse is delivered by the escape wheel to the hairspring and not to the balance wheel

[@josephflores349]

et