Rotating resonator with flexure bearing maintained by a detached lever escapement

Patent metadata

Field	Value
Publication number	US-11487245-B2
Application number	US-201716462801-A
Country	US
Kind code	B2
Filing date	Jul 27, 2017
Priority date	Nov 23, 2016
Publication date	Nov 1, 2022
Grant date	Nov 1, 2022

Abstract

Timepiece regulator (300) comprising a detached lever (7) escapement mechanism (200), and a resonator (100) with a quality factor Q including an inertia element (2) comprising an impulse pin (6) integral with an inertia element (2) and cooperating with a fork (8) of the lever (7), this inertia element (2) being subjected to the action of elastic return means (3) directly or indirectly fixed to the plate (1) and being arranged to cooperate indirectly with an escape wheel set (4) comprised in the escapement mechanism (200), this resonator mechanism (100) is a resonator with a virtual pivot rotating about a main axis (DP), with a flexure bearing subjected to the return force of at least two flexible strips (5) attached to the plate (1), defining together a virtual pivot with a main axis (DP), the lever (7) pivoting about a secondary axis (DS), and the fork (8) is enlarged in comparison to the fork of a conventional Swiss lever.

First claim

The invention claimed is:

1. A timepiece regulating mechanism, comprising, arranged on a main plate,
a resonator mechanism, and
an escapement mechanism which is subjected to the torque of drive means comprised in a movement,
said resonator mechanism comprising an inertia element arranged to oscillate with respect to said plate, said inertia element being subjected to the action of elastic return means directly or indirectly attached to said plate, and
said inertia element being arranged to cooperate indirectly with an escape wheel set comprised in said escapement mechanism, wherein said resonator mechanism is a resonator with a virtual pivot rotating about a main axis, with a flexure bearing including at least two flexible strips, and including an impulse pin integral with said inertia element, and said escapement mechanism includes a lever pivoting about a secondary axis and including a lever fork arranged to cooperate with said impulse pin, and is a detached escapement mechanism,
wherein, during the operating cycle, said resonator mechanism has at least one phase of freedom in which said impulse pin is at a distance from said lever fork, wherein, during each vibration,
in a contact phase,
said impulse pin penetrates said lever fork with a depth of travel (P) greater than 100 micrometers, and

in an unlocking phase,
said impulse pin remains at a distance from said lever fork with a safety distance (S) greater than 25 micrometers, and said impulse pin and said lever fork are dimensioned such that the width of said lever fork is greater than (P+S)/sin(α/2+β/2), where a is a total angular travel of the lever fork from one side to the other and β is an overall lift angle of the resonator during which said impulse pin is in contact with said lever fork, said depth of travel (P) and said safety distance (S) being measured radially with respect to said main axis.

2. The regulating mechanism according to claim 1 , wherein said overall lift angle (β) of the resonator is less than 10°.

3. The regulating mechanism according to claim 1 , wherein the inertia (IB) of said inertia element with respect to said main axis on the one hand, and the inertia (IA) of said lever with respect to said secondary axis on the other hand, are such that the ratio IB/IA is greater than 2Q·α 2 /(0.1·π·β 2 ), where Q is a quality factor of the resonator mechanism.

4. The regulating mechanism according to claim 1 , wherein said overall lift angle (β) of the resonator is less than twice the angle of amplitude by which said inertia element deviates furthest, in only one direction of motion, from a rest position.

5. The regulating mechanism according to claim 1 , wherein the angle of amplitude, by which said inertia element deviates furthest from a rest position, is comprised between 5° and 40°.

6. The regulating mechanism according to claim 1 , wherein said lever is in a single layer of silicon, placed on an arbor pivoted with respect to said plate.

7. The regulating mechanism according to claim 1 , wherein said escape wheel set is a silicon escape wheel.

8. The regulating mechanism according to claim 1 , wherein said escape wheel set is an escape wheel which is perforated to minimize its inertia with respect to its axis of pivoting.

9. The regulating mechanism according to claim 1 , wherein said lever is perforated to minimize its said inertia (IA) with respect to said secondary axis.

10. The regulating mechanism according to claim 1 , wherein said lever is symmetrical with respect to said secondary axis.

11. The regulating mechanism according to claim 1 , wherein the largest dimension of said inertia element is greater than half the largest dimension of said plate.

12. The regulating mechanism according to claim 1 , wherein said main axis, said secondary axis and the axis of pivoting of said escape wheel set, are arranged to be centered at a right angle whose apex is on said secondary axis.

13. The regulating mechanism according to claim 1 , wherein said flexure bearing includes two flexible strips which are crossed in projection onto a plane perpendicular to said main axis, at said virtual pivot defining said main axis, and located in two parallel and distinct levels.

14. The regulating mechanism according to claim 13 , wherein said two flexible strips, in projection onto a plane perpendicular to said main axis, form therebetween an angle comprised between 59.5° and 69.5°, and intersect at between 10.75% and 14.75% of their length, such that said resonator mechanism has a deliberate isochronism error which is the additive inverse of the loss error at the escapement of said escapement mechanism.

15. The regulating mechanism according to claim 13 , wherein said two flexible strips are identical and are positioned in symmetry.

16. The regulating mechanism according to claim 13 , wherein each said flexible strip forms part of a one-piece assembly in one piece with means thereof for alignment and attachment to said plate or to an intermediate elastic suspension strip attached to said plate and arranged to allow a displacement of said flexure bearing and of said inertia element in the direction of said main axis.

17. The regulating mechanism according to claim 1 , wherein at least said resonator mechanism is attached to an intermediate, elastic suspension strip attached to said plate and arranged to allow a displacement of said resonator mechanism in the direction of said main axis, and said plate includes at least one shock absorber stop at least in the direction of said main axis, arranged to cooperate with at least one stiff element of said inertia element.

18. The regulating mechanism according to claim 1 , wherein said inertia element includes inertia blocks for adjusting rate and unbalance.

19. The regulating mechanism according to claim 1 , wherein said impulse pin is in one-piece with a said flexible strip.

20. The regulating mechanism according to claim 1 , wherein said lever includes bearing surfaces arranged to cooperate in abutment with teeth comprised in said escape wheel set and to limit the angular travel of said lever.

21. The regulating mechanism according to claim 1 , wherein said flexure bearing is made of oxidized silicon to compensate for the effects of temperature on the rate of said regulating mechanism.

22. A timepiece movement including drive means and a regulating mechanism according to claim 1 , wherein said escapement mechanism is subjected to the torque of said drive means.

23. A watch including a regulating mechanism according to claim 1 .

Assignees

• Eta Sa Mft Horlogere Suisse

Inventors

• Winkler Pascal
• Helfer Jean-Luc
• Di Domenico Gianni

Classifications

• G04B15/08 Primary

  Lever escapements · CPC title

• G04B17/28

  for the effect of imbalance of the weights, e.g. tourbillon · CPC title

• G04B17/045 Primary

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

• G04B15/14

  Component parts or constructional details, e.g. construction of the lever or the escape wheel {(assembly and manufacture of the spring G04B1/145; assembly and manufacture of components, e.g. pinions, spindles G04B13/02; lubrication of clockwork bearings G04B31/008; oils for clockwork bearings in general G04B31/08)} · CPC title

• G04B17/26

  for the effect of variations of the impulses · CPC title