Magnetic clock escapement and device for regulating the operation of a clock movement

Patent metadata

Field	Value
Publication number	US-9891591-B2
Application number	US-201515308902-A
Country	US
Kind code	B2
Filing date	Sep 4, 2015
Priority date	Sep 9, 2014
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

A magnetic clock escapement, and a regulating device, the escapement including a first circular network formed by N1 magnetic lines and a second circular network formed by N2 magnetic lines, N2 being different from N1. The first and second networks are superimposed to define a combined pattern having a magnetic Moiré effect. The combined pattern is coupled magnetically to at least one magnet of a resonator to pace operation of a mechanical clock movement. The first magnetic structure is carried by an escapement wheel and can rotate relative to the second fixed magnetic structure with an angular frequency F1. The combined pattern rotates with a greater angular frequency F2 and equal to the angular frequency F1 multiplied by the number N1 and divided by the number ΔN equal to this number N1 minus the number N2, F2=F1·N1/ΔN.

First claim

The invention claimed is:

1. A magnetic escapement equipping a mechanical clock movement and comprising:
an escapement wheel driven by a motor device and coupled to a resonator of the mechanical clock movement, the escapement wheel comprising a first magnetic structure defining, within a non-zero radial range of the escapement wheel, a first periodic pattern with a first angular period P1 such that 360°/P1 is equal to a first whole number N1;
at least one magnet mounted on the resonator and coupled magnetically to the escapement wheel such that, when the mechanical clock movement functions, the magnet has a periodic resonance movement at a resonance frequency and such that the escapement wheel rotates with a frequency proportional to the resonance frequency;
a second magnetic structure parallel to the first magnetic structure and defining, within the radial range, a second periodic pattern having a second angular period P2 such that 360°/P2 is equal to a second whole number N2 which is different from the whole number N1, the difference in absolute value |ΔN| between the numbers N1 and N2 being a number less than or equal to N/2, |ΔN|<=N/2, N being the lower number of the numbers N1 and N2;
wherein the first and second magnetic structures are configured such that, when the clock movement functions, the first magnetic structure has a rotation relative to the second magnetic structure at a first relative angular frequency F1 rel ; and
wherein the first periodic pattern and the second periodic pattern are selected such that they generate, within the radial range, in projection on a geometric surface parallel to the first and second magnetic structures, a combined pattern coupled to the magnet and which defines, alternately, at least the number |ΔN| of first zone(s) with a first proportion of magnetic surface and at least the number |ΔN| of second zone(s) with a second proportion of magnetic surface less than the first proportion, and such that the combined pattern rotates relative to the second magnetic structure with a second relative angular frequency F2 rel equal to the first relative angular frequency F1 rel multiplied by the number N1 and divided by the difference ΔN between the numbers N1 and N2, F2 rel =F1 rel ·N1/ΔN where ΔN=N1−N2.

2. The magnetic escapement according to claim 1 , wherein the magnet has a magnetization axis perpendicular to the geometric surface of the combined pattern.

3. The magnetic escapement according to claim 1 , wherein the combined pattern defines a periodic combined pattern having, alternately, the number |ΔN| of first zone(s) and the number |ΔN| of second zone(s), any first zone and an adjacent second zone defining an angular period P3 of the periodic combined pattern, the value of which is equal to 360° divided by the number |ΔN|, P3=360°/|ΔN|.

4. The magnetic escapement according to claim 3 , wherein the first pattern forms a first circular network with lines made of magnetic material separated by lines defined by an empty space or a substantially non-magnetic material, and the second pattern forms a second circular network with lines made of magnetic material separated by lines defined by an empty space or a substantially non-magnetic material.

5. The magnetic escapement according to claim 4 , wherein the lines made of magnetic material of the first circular network extend substantially over half of the first angular period P1 and the lines made of magnetic material of the second circular network extend substantially over half of the second angular period P2.

6. A regulating device for regulating operation of a clock movement comprising:
the magnetic escapement according to claim 4 ;
a resonator, one resonant part of which supporting the magnet is subject, during functioning of the clock movement, to an oscillation according to one degree of freedom;
wherein the resonator is configured such that the center of the magnet in its rest position is substantially situated, for any angular position of the escapement wheel, on a zero position circle which is centered on the axis of rotation of the escapement wheel and which is traversed by the degree of freedom of the resonant part of the resonator; and
wherein the periodic combined pattern is situated on a first side of the zero position circle, projected perpendicularly in the geometric surface, the annular region of the first and second magnetic structures, defined by the radial range, being coupled magnetically to the magnet in a first alternation of each period of the oscillation such that, for each period of the oscillation, the periodic combined pattern rotates by an angular distance equal to its angular period P3.

7. The regulating device according to claim 6 , the periodic combined pattern being a first periodic combined pattern and the radial range being a first radial range;
wherein the first and second magnetic structures define respectively, within a second non-zero radial range of the escapement wheel situated on an other side of the zero position circle, relative to the first radial range, a third periodic pattern and a fourth periodic pattern which generate a second periodic combined pattern, having, alternately, the number |ΔN| of third zone(s), with a third proportion of magnetic surface greater than the second proportion, and the number |ΔN| of fourth zone(s), with a fourth proportion of magnetic surface which is less than the first and third proportions, the second periodic combined pattern having the angular period P3; and
wherein the second periodic combined pattern is offset angularly by half an angular period P3 relative to the first periodic combined pattern, the second periodic combined pattern rotating likewise with the second relative angular frequency F2 rel , the annular region of the first and second magnetic structures, defined by the second radial range, being coupled magnetically to the magnet in a second alternation of each period of the oscillation.

8. The regulating device according to claim 7 , wherein the third periodic pattern forms a third circular network with lines made of magnetic material, separated by lines defined by an empty space or a substantially non-magnetic material, and the fourth periodic pattern forms a fourth circular network with lines made of magnetic material, separated by lines defined by an empty space or a substantially non-magnetic material, the third and fourth circular networks having an angular period respectively equal to the first and second angular periods P1 and P2.

9. The regulating device according to claim 8 , wherein the first and second periodic combined patterns are substantially contiguous; and
wherein the first and third circular networks or the second and fourth circular networks together form a same circular network which extends at least over the first and second radial ranges.

10. The regulating device according to claim 7 , wherein the resonator includes a tuning fork with two branches, the magnet forming a first magnet fixed to the free end of a first branch, the resonator further includes a second magnet fixed to the free end of the second branch; and wherein the number |ΔN| is an even number.

11. The regulating device according to claim 10 , wherein the number |ΔN| is equal to 2, |ΔN|=2.

12. The regulating device according to claim 6 , the magnet being a first magnet;
wherein the magnetic escapement comprises a second magnet mounted on the resonator and supported by the resonant part or by another resonant part of the resonator, the second magnet configured relative to the first magnet on an other side of the first and second magnetic structures to be aligned with the first magnet in a direction substantially paralle

Assignees

• Swatch Group Res & Dev Ltd

Inventors

• Di Domenico Gianni

Classifications

• 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

• G04C5/005 Primary

  Magnetic or electromagnetic means · CPC title