Optimised magneto-mechanical timepiece escapement mechanism

Patent metadata

Field	Value
Publication number	US-11567456-B2
Application number	US-201916571428-A
Country	US
Kind code	B2
Filing date	Sep 16, 2019
Priority date	Sep 19, 2018
Publication date	Jan 31, 2023
Grant date	Jan 31, 2023

Abstract

An oscillator includes a resonator, which has an inertial mass returned by an elastic return and carries entry and exit pallets cooperating with teeth of an escape wheel each provided with a magnet. Each pallet includes a magnetic arrangement, with an annular sector, centred on the axis of oscillation of the resonator, defining a first magnetic barrier area extending above and/or below a mechanical pallet-stone of the entry pallet or exit pallet, over the entire length of this mechanical pallet-stone acting as support for the teeth during the supplementary arc, in order to form a magnetic cylinder escapement mechanism.

First claim

The invention claimed is:

1. A timepiece oscillator, comprising:
at least one resonator, with an inertial mass returned by elastic return means with respect to a fixed structure, said resonator oscillating about an axis of oscillation, said inertial mass carrying an entry pallet and an exit pallet;
an escapement mechanism including an escape wheel arranged to rotate about an axis of rotation and including end teeth, each arranged to cooperate with said entry pallet or with said exit pallet to maintain the oscillation of said resonator,
wherein said escapement mechanism is a magneto-mechanical escapement mechanism and said escape wheel includes at least one magnet at the end of each said tooth, said teeth being arranged to act alternately with said entry and exit pallets, and said entry pallet includes a first magnetic arrangement, said exit pallet includes a second magnetic arrangement, and said first magnetic arrangement and said second magnetic arrangement each include an annular sector, centered on said axis of oscillation of said resonator, and defining a first magnetic barrier area, which extends above and/or below said mechanical pallet-stone of said entry pallet or of said exit pallet, with reference to the direction of said axis of oscillation, over the entire length of said mechanical pallet-stone able to act as support for said teeth during the supplementary arc, in order to form a magnetic cylinder escapement mechanism.

2. The timepiece oscillator according to claim 1 , wherein said first magnetic arrangement and/or said second magnetic arrangement includes, to improve the self-starting function, on said entry pallet and/or on said exit pallet, at least one magnetic pad which includes at least one magnet, and which extends into a second self-starting improvement area, which is an annular sector, centered on said axis of rotation of said wheel, and which extends, as regards said entry pallet, substantially in a tangent direction of entry which is tangent to said wheel and which passes above and/or below said mechanical pallet-stone of said entry pallet, and/or as regards said exit pallet, substantially in an tangent direction of exit which is tangent to said wheel and which passes above and/or below said mechanical pallet-stone of said exit pallet, with reference to the direction of said axis of oscillation, in order to cover at least one impulse face comprised in the end of said entry pallet and/or said exit pallet.

3. The timepiece oscillator according to claim 2 , wherein said magnetic pad is extended, from said magnetic barrier and in the direction tangent to said wheel and which goes in the direction of rotation of said wheel, by a magnetic tail portion, which is substantially in the alignment of said magnetic pad, and which is arranged to apply to said magnet of said wheel a force that tends to drive it tangentially, and which is arranged to combat the friction force at the distal end of said pallet on the side of said escape wheel.

4. The timepiece oscillator according to claim 3 , wherein said magnetic tail portion is arranged in increasing radii from said axis of rotation of said wheel away from said magnetic pad.

5. The timepiece oscillator according to claim 3 , wherein said magnetic tail portion is made in a set of decreasing steps.

6. The timepiece oscillator according to claim 3 , wherein the length of said magnetic pad is greater than that of said magnetic tail portion, in order to give a first impulse.

7. The timepiece oscillator according to claim 3 , wherein said magnetic pad and said magnetic tail portion are arranged to define a continuous magnetic field on the curvilinear arc on which they are arranged.

8. The timepiece oscillator according to claim 2 , wherein the total curvilinear length of said magnetic pad and of any magnetic tail portion which extends said magnetic pad, is close to a half-pitch of the ends of said teeth on a circle which defines the envelope of the trajectory of said teeth of said escape wheel.

9. The timepiece oscillator according to claim 2 , wherein said magnetic pad includes, at its distal end opposite to said magnetic barrier, a magnetic lug on the side opposite to said escape wheel, and extending the second self-starting improvement area.

10. The timepiece oscillator according to claim 1 , wherein said magnetic arrangement includes a third isochronism correction area which extends, from the point of view of said teeth of said wheel, upstream of said first magnetic barrier area, and, with respect to said axis of rotation of said escape wheel, beyond the distal end of said pallet-stone, at the entry in a tangential direction of entry opposite to the direction of rotation of said wheel and in a radial direction of entry away from the center of rotation of said wheel, and at the exit in a tangential direction of exit opposite to the direction of rotation of said wheel and in a radial direction of exit away from the center of rotation of said wheel, in order to cover, above and/or below said mechanical pallet-stone of said entry pallet or of said exit pallet, with reference to the direction of said axis of oscillation, said magnet of said wheel which is resting on said pallet during the supplementary arc.

11. The timepiece oscillator according to claim 10 , wherein said third area is located, with respect to said axis of rotation of said escape wheel, beyond said second self-starting improvement area which delimits, with said first magnetic barrier area, said third isochronism correction area.

12. The timepiece oscillator according to claim 10 , wherein said third area is an area of weak magnetic attractive or repulsive interaction with said magnet, of lower magnetic interaction than that of the other areas of magnetic interaction of said magnetic arrangement of which it forms part.

13. The timepiece oscillator according to claim 10 , wherein said third area contains iron or magnets which are in magnetic attractive or repulsive interaction with said magnet during the supplementary arc.

14. The timepiece oscillator according to claim 13 , wherein the mean quantity of iron or magnet per surface unit is constant in the direction tangent to said wheel, and varies in the direction tangent to said pallet, in order to exhibit a magnetic interaction with said magnet, which is variable according to the angle of said inertial mass with respect to a rest position.

15. The timepiece oscillator according to claim 10 , wherein said third area contains a sacrificial excess of iron or of magnets, arranged to be at least partly selectively removed according to the result of measurement of the anisochronism of said complete oscillator, in order to restore the isochronism of said oscillator.

16. The timepiece oscillator according to claim 1 , wherein said inertial mass includes at least one balance.

17. A timepiece movement comprising:
at least one of the timepiece oscillator according to claim 1 .

18. A watch comprising:
at least one of the movement according to claim 17 .

Assignees

• Swatch Group Res & Dev Ltd

Inventors

• Di Domenico Gianni
• Favre Jerome
• Lechot Dominique
• Hinaux Baptiste
• Matthey Olivier
• Winkler Pascal
• Stranczl Marc
• Willemin Michel
• Odeh Ahmad

Classifications

• G04C3/04

  wherein movement is regulated by a balance · CPC title

• G04B15/04

  Cylinder escapements · CPC title

• G04C5/005 Primary

  Magnetic or electromagnetic means · CPC title

• G04B17/045

  with oscillating blade springs (mechanical oscillations maintained by electro-magnetic means, e.g. tuning forks G04C3/10) · CPC title