Timepiece comprising a tourbillon

Patent metadata

Field	Value
Publication number	US-11640141-B2
Application number	US-201916410367-A
Country	US
Kind code	B2
Filing date	May 13, 2019
Priority date	Jun 7, 2018
Publication date	May 2, 2023
Grant date	May 2, 2023

Abstract

The timepiece includes a tourbillon including a carriage that bears a sprung balance and a magnetic escapement device, the latter including an escape wheel set, formed of an annular magnetic structure, and a magnetic element coupled with the magnetic structure and having an oscillating movement that is synchronous with the oscillation of the mechanical resonator. The mechanical escapement is arranged so as to have alternately energy accumulation phases, from a conversion of mechanical energy supplied by the barrel into magnetic potential energy in the magnetic escapement, and transfer phases of energy accumulated in the magnetic escapement to the magnetic resonator. During the energy transfer phases, the magnetic element is subjected to a magnetic force such that the magnetic escapement then converts into mechanical energy magnetic potential energy accumulated in the preceding energy accumulation phase to be able to maintain the oscillation of the mechanical resonator.

First claim

The invention claimed is:

1. A timepiece comprising:
a timepiece movement fitted with a tourbillon comprising a carriage arranged rotating about a main axis, a barrel arranged to accumulate mechanical energy and a geartrain kinematically linking the tourbillon carriage to the barrel, the tourbillon bearing a mechanical resonator, formed of a balance and a balance-spring, and an escapement device; wherein the escapement device is a magnetic escapement that comprises an escape wheel set formed of an escape pinion and at least one magnetic structure, which has a general annular shape centred on an axis of rotation of the escape wheel set, said magnetic escapement further comprising a magnetic element or a plurality of magnetic elements, said magnetic element or each magnetic element being arranged so as to have an oscillating movement that is synchronous with the oscillation of the mechanical resonator and that has a radial component different to zero relative to said axis of rotation, said magnetic element being coupled with said at least one magnetic structure or each magnetic element of said plurality of magnetic elements being coupled, at least momentarily periodically, with said at least one magnetic structure such that the escape wheel set rotates by a predetermined angular period at each oscillation period of the balance; wherein the magnetic escapement is arranged so as to have, in normal timepiece movement operation, alternately energy accumulation phases, from a conversion of mechanical energy supplied by the barrel into magnetic potential energy in the magnetic escapement, and transfer phases of energy accumulated in the magnetic escapement to the magnetic resonator; and wherein the magnetic escapement is arranged such that:
during each energy accumulation phase, said at least one magnetic structure is subjected to a magnetic force torque, relative to said axis of rotation, having an opposite direction to that of a drive torque, applied by the barrel via the tourbillon carriage to the escape wheel set, and an intensity less than that of said drive torque, such that the escape wheel set rotates by a certain angle to enable the accumulation of a certain magnetic potential energy in the magnetic escapement;
during each transfer phase of energy, said magnetic element or each magnetic element of a set of magnetic elements, that of the plurality of magnetic elements was coupled with said at least one magnetic structure during a preceding energy accumulation phase, is subjected to a radial magnetic force, relative to said axis of rotation, during an alternation of the oscillating movement thereof and in the direction of the radial component of said oscillating movement during said alternation, such that the magnetic escapement then converts into mechanical energy magnetic potential energy accumulated in the preceding energy accumulation phase to be able to maintain the oscillation of the mechanical resonator,
wherein the oscillation frequency of the mechanical resonator is substantially equal to or greater than six Hertz.

2. The timepiece according to claim 1 , wherein said magnetic escapement comprises a stopper coupling momentarily, in each oscillation alternation of the mechanical resonator, said mechanical resonator with the escape wheel set, the stopper bearing said magnetic element or said plurality of magnetic elements and being subjected, when the mechanical resonator oscillates, to a to-and-fro movement interspersed with rest phases wherein the stopper is alternately stopped in two rest positions; wherein said at least one magnetic structure defines in the two rest positions of the stopper respectively a first magnetic potential energy curve and a second magnetic potential energy curve, both as a function of the angle of the escape wheel set and each having:
increasing portions for the magnetic interaction between said at least one magnetic structure and said magnetic element or a set of magnetic elements that, of the plurality of magnetic elements, are coupled with said at least one magnetic structure in a corresponding rest position of the stopper, these increasing portions being configured so as to be suitable for being climbed, during normal timepiece movement operation, by said magnetic element or by said set of magnetic elements, and
magnetic barriers following respectively the increasing portions, said magnetic barriers being arranged so as to be suitable for stopping angular progress of the escape wheel set while the stopper is in the corresponding rest position;
said increasing portions of the first magnetic potential energy curve being respectively offset angularly relative to the increasing portions of the second magnetic potential energy curve, each magnetic barrier of one of the first and second magnetic potential energy curves being situated angularly between two successive magnetic barriers of the other of these first and second magnetic potential energy curves; the magnetic escapement being arranged such that:
the energy accumulation phases occur essentially and respectively in the successive rest phases of the stopper,
during each energy accumulation phase, said magnetic element or a set of magnetic elements, which of said plurality of magnetic elements are at that time coupled with said at least one magnetic structure, is suitable for climbing at least partially one of the increasing portions during a certain rotation of the escape wheel set,
the increasing portions of the first and second magnetic potential energy curves may, during said normal timepiece movement operation, be respectively and alternately climbed at least partially during successive energy accumulation phases;
and wherein the magnetic escapement is further arranged such that:
the transfer phases of energy occur respectively in successive alternations of the to-and-fro movement of the stopper,
said magnetic escapement is subjected, during said normal timepiece movement operation, overall to a decrease in magnetic potential energy during each of the successive alternations of the to-and-fro movement of the stopper, and
the decrease in magnetic potential energy in the magnetic escapement results essentially from work of said radial magnetic force applied on said magnetic element or on each magnetic element of a set of magnetic elements that, of the plurality of magnetic elements, were coupled with said at least one magnetic structure during a preceding rest phase, said work of the radial magnetic force thus being supplied to the stopper that is arranged to transmit same mostly to the mechanical resonator, such that said mechanical resonator can receive a mechanical energy impulse in each alternation of the to-and-fro movement of said stopper.

3. The timepiece according to claim 2 , wherein the tourbillon further bears an intermediate wheel set of which an intermediate wheel meshes with the escape pinion and an intermediate pinion meshes with a fixed second wheel comprised by the timepiece movement, the intermediate wheel set being a reducer wheel set of the rotational frequency of the escape wheel set and being arranged such that said tourbillon carriage performs one revolution on itself per minute.

4. The timepiece according to claim 3 , wherein the oscillation frequency of the mechanical resonator has a value situated between, inclusive, eight Hertz and twelve Hertz.

5. The timepiece according to claim 3 , wherein the rotational frequency of the escape wheel set has a value between, inclusive, one quarter and one sixteenth of the oscillation frequency of the mechanical resonator.

6. The timepiece according to claim 1 , wherein the magnetic escapement comprises at least two similar magnetic elements that are situated on the same side of said magnetic structure and that are both coupled simultaneously with sai

Assignees

• Montres Breguet Sa

Inventors

• Karapatis Polychronis Nakis
• Stranczl Marc
• Legeret Benoit

Classifications

• G04B45/02

  Time pieces of which the clockwork is visible partly or wholly {(figures or parts thereof moved by the clockwork G04B45/0038)} · CPC title

• G04B1/22

  Compensation of changes in the motive power of the mainspring (by mechanical shaping of the mainspring G04B1/14 {; automatic regulation of the pendulum G04B18/003; of the regulator G04B19/28}) · 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

• G04B15/06

  Free escapements · CPC title

• G04B17/285 Primary

  Tourbillons or carrousels · CPC title