Timepiece incorporating an actuator comprising an electromechanical device

Patent metadata

Field	Value
Publication number	US-12013668-B2
Application number	US-202217673146-A
Country	US
Kind code	B2
Filing date	Feb 16, 2022
Priority date	Mar 23, 2021
Publication date	Jun 18, 2024
Grant date	Jun 18, 2024

Abstract

A timepiece (2) includes an actuator, which applies braking pulses to the balance, which has an electromechanical device (6) and an electric control circuit (8). The device (6) includes a flexible member (16), formed by an elastic blade (20) and a mechanical element (22) defining a braking pad, and an electromagnetic system (10) formed by a coil carried by the flexible member and by a permanent magnet rigidly connected to a support (18) of the electromechanical device. When an electric pulse is provided to the coil, an electromagnetic force of repulsion is engendered between the coil and the permanent magnet so the mechanical element moves to a position of contact with the balance. To stabilise the rest position of the flexible member, a magnetic element (26) is rigidly connected to the coil to exert a magnetic return force complementary to the force of the elastic blade is provided.

First claim

The invention claimed is:

1. A timepiece, comprising:
an actuator including an electromechanical device, which comprises an electromagnetic system and a mechanical element that is mobile in translation and associated with the electromagnetic system, and an electric control circuit,
the electromagnetic system being formed by a permanent magnet and a coil, one out of the two of which is carried by a flexible member of the electromechanical device and the other by a support of this flexible member, said mechanical element being formed by said flexible member and the actuator being arranged in such a way as to allow, in response to an electric activation signal generated by the electric control circuit and provided to the coil to engender an electromagnetic force between this coil and said permanent magnet, a movement of the mechanical element from a rest position, in which it is provided that the mechanical element remains in the absence of an activation of the electromagnetic system, to a position of contact with a determined part of the timepiece,
wherein said flexible member is formed at least partially by an elastic element that is arranged to engender a mechanical force of return of the mechanical element in the direction of said rest position from said contact position for more than half the distance that the mechanical element travels from said contact position to said rest position, when the electric control circuit generates said electric activation signal, between the rest position and the contact position, this contact position ending said at least a majority of said distance, and
wherein the actuator further comprises a magnetic element arranged to interact with said permanent magnet to engender therebetween a magnetic force that is exerted on the mechanical element when the mechanical element is in the rest position, the magnetic force having a direction opposite to that of said electromagnetic force over at least an initial part of said distance from the rest position and an intensity which decreases, over said at least an initial part, when the mechanical element moves away from the rest position and which is less than the intensity that said electromagnetic force has for any position of said mechanical element in said at least an initial part.

2. The timepiece according to claim 1 , wherein said magnetic element includes a ferromagnetic material.

3. The timepiece according to claim 1 , wherein said permanent magnet is a first magnet, wherein said magnetic element is formed by a second permanent magnet arranged in magnetic attraction with the first magnet when said mechanical element is in the rest position.

4. The timepiece according to claim 2 , wherein said permanent magnet has a shape of a disc, and wherein said magnetic element is arranged in such a way as to be aligned on a central axis of the permanent magnet when the mechanical element is in the rest position.

5. The timepiece according to claim 2 , wherein said permanent magnet has an annular shape.

6. The timepiece according to claim 3 , wherein the first permanent magnet has a shape of a disc, and wherein said magnetic element is arranged in such a way as to be aligned on a central axis of the first permanent magnet when the mechanical element is in the rest position.

7. The timepiece according to claim 3 , wherein the first permanent magnet has an annular shape.

8. The timepiece according to claim 4 , wherein said ferromagnetic element has a shape of a disc.

9. The timepiece according to claim 6 , wherein the second permanent magnet has a shape of a disc.

10. The timepiece according to claim 6 , wherein said magnetic element includes the second permanent magnet, which has an annular shape defining a central circle, or a plurality of permanent magnets arranged along a geometric circle; wherein said central circle or said geometric circle has a diameter that is greater than the diameter of the first permanent magnet and is, when the flexible member is in the rest position, centred on the central axis of the first permanent magnet; and wherein the diameter of the central circle or of the geometric circle is selected so that said magnetic force between the first permanent magnet and the second permanent magnet, respectively the plurality of permanent magnets, has an inversion of direction during said movement of said mechanical element from the rest position to the contact position.

11. The timepiece according to claim 5 , wherein said ferromagnetic element has a shape of a disc, and wherein the ferromagnetic element is arranged in such a way as to be aligned on a central axis of said permanent magnet when the mechanical element is in its rest position.

12. The timepiece according to claim 11 , wherein the ferromagnetic element is arranged in such a way as to be positioned at least partially in an inner space of the annular permanent magnet when said mechanical element is in the rest position.

13. The timepiece according to claim 11 , wherein the permanent magnet, the ferromagnetic element and the elastic element are configured and arranged in such a way that the sum of said mechanical return force and said magnetic force has, over all of said distance that said mechanical element can travel, a direction opposite to the direction of said movement of this mechanical element from the rest position to the contact position, so as to form over all of said distance a total force of return of the mechanical element towards the rest position.

14. The timepiece according to claim 7 , wherein the second permanent magnet has a shape of a disc, and wherein the second permanent magnet is arranged in such a way as to be aligned on a central axis of the first permanent magnet when the mechanical element is in the rest position.

15. The timepiece according to claim 14 , wherein the second permanent magnet is arranged so that said magnetic force between the first permanent magnet and the second permanent magnet has an inversion of direction during said movement of said mechanical element from the rest position to the contact position.

16. The timepiece according to claim 15 , wherein the first permanent magnet, the second permanent magnet and the elastic element are configured and arranged in such a way that the sum of said mechanical return force and said magnetic force has, over all of said distance that said mechanical element can travel, a direction opposite to the direction of said movement of this mechanical element from the rest position to the contact position, so as to form over all of said distance a total force of return of the mechanical element towards the rest position.

Assignees

• Swatch Group Res & Dev Ltd

Inventors

• Imboden Matthias
• Mignot Jean-Pierre

Classifications

• G04C11/084

  acting on the balance · CPC title

• G04C3/066

  Constructional details, e.g. disposition of coils · CPC title

• G04C3/047

  using other coupling means, e.g. electrostrictive, magnetostrictive · CPC title

• H03B5/40

  being a magnetostrictive resonator (H03B5/42 takes precedence; selection of magneto-strictive material {H01F1/00}; H10N30/00) · CPC title

• G04C3/045 Primary

  with constant impulses · CPC title