Method for manufacturing horological balance springs

Patent metadata

Field	Value
Publication number	US-12481248-B2
Application number	US-202418941193-A
Country	US
Kind code	B2
Filing date	Nov 8, 2024
Priority date	Dec 19, 2023
Publication date	Nov 25, 2025
Grant date	Nov 25, 2025

Abstract

There is provided a method for manufacturing a batch of horological balance springs ( 2 a), the average of whose stiffnesses lies within a predetermined range, and the method includes forming in a wafer the horological balance springs ( 2 b, 2 c) with dimensions that differ from the dimensions required to obtain the batch of horological balance springs ( 2 a), the average of whose stiffnesses lies within the predetermined range, determining the stiffnesses of the systems, computing a dimensional correction to be applied to the horological balance springs, and modifying the dimensions of the horological balance springs ( 2 b, 2 c) formed, on the basis of a dimensional correction computed to obtain the batch of horological balance springs ( 2 a).

First claim

The invention claimed is:

1 . A method for manufacturing a batch of horological balance springs ( 2 a ), comprising an average stiffness within a predetermined range, which method comprises the following steps of:
a) forming, in a wafer ( 1 ), horological balance springs ( 2 b , 2 c ), of the batch of horological balance springs ( 2 a ), with dimensions that differ from dimensions required to obtain the batch of horological balance springs ( 2 a ) comprising the average stiffness within said predetermined range; b) forming, in the wafer ( 1 ), systems ( 3 ) for indicating a reference stiffness for determining stiffnesses of the batch of horological balance springs ( 2 a ); c) determining the stiffnesses of said systems ( 3 ) formed; d) computing a dimensional correction to be applied to the horological balance springs ( 2 b , 2 c ) formed, on the basis of the determined stiffnesses of said systems ( 3 ); and e) modifying the dimensions of the horological balance springs ( 2 b , 2 c ) formed, on the basis of a dimensional correction computed to obtain the batch of horological balance springs ( 2 a ), the average of whose stiffnesses lies within said predetermined range, wherein the systems ( 3 ) comprise a first system ( 3 ) and a second system ( 3 ), wherein the horological balance springs ( 2 b , 2 c ) comprise a first horological balance spring ( 2 b , 2 c ) and a second horological balance spring ( 2 b , 2 c ), and wherein forming, in the wafer ( 1 ), the systems ( 3 ) comprises:
arranging the first system ( 3 ) closer to the first horological balance spring ( 2 b , 2 c ) than to any other of the horological balance springs ( 2 b , 2 c ), and
arranging the second system ( 3 ) closer to the second horological balance spring ( 2 b , 2 c ) than to any other of the horological balance springs ( 2 b , 2 c ).

2 . The method according to claim 1 , wherein forming the horological balance springs ( 2 b , 2 c ) and forming said systems ( 3 ) are carried out by deep reactive-ion etching.

3 . The method according to claim 1 , wherein forming the systems ( 3 ) comprises forming a system ( 3 ), of the systems ( 3 ), in the wafer ( 1 ) and closer to a first one of the horological balance springs ( 2 b , 2 c ) than to a second one of the horological balance springs ( 2 b , 2 c ).

4 . The method according to claim 1 , wherein forming said systems ( 3 ) comprises forming, in the wafer ( 1 ), a plurality of groups of oscillating elements ( 10 ), each group of the groups of oscillating elements ( 10 ) constituting each of said systems ( 3 ) respectively, and each group surrounding a respective one of the horological balance spring ( 26 , 2 c ) in the wafer ( 1 ).

5 . The method according to claim 1 , wherein forming said systems ( 3 ) comprises forming, in the wafer ( 1 ), a plurality of oscillating elements ( 10 ) each of which is arranged closer to respective ones of the horological balance spring ( 2 b , 2 c ) than others of the horological balance springs ( 2 b , 2 c ).

6 . The method according to claim 1 , wherein determining the stiffnesses comprises estimating at least one resonant frequency of each of the systems ( 3 ).

7 . The method according to claim 1 , wherein determining the stiffnesses comprises estimating at least one resonant frequency of each of the systems ( 3 ) by an electronic device executing an algorithm for computing stiffness on a basis of the resonant frequency.

8 . The method according to claim 1 , wherein determining the stiffnesses comprises estimating at least one resonant frequency of each of the systems ( 3 ) by an electronic device executing an algorithm for computing stiffness on a basis of the resonant frequency, wherein the stiffness is any of a stiffness of an oscillating element ( 10 ) of the systems ( 3 ), a first average stiffness of all of a plurality of oscillating elements ( 10 ) of the systems ( 3 ), and a second average stiffness of less than all of the plurality of oscillating elements ( 10 ) of the systems ( 3 ).

9 . The method according to claim 1 , wherein the computing the dimensional correction comprises determining, from the stiffnesses of said systems ( 3 ), a thickness (e) of material to be added to or removed from at least one dimension of the horological balance spring ( 2 b , 2 c ) of the batch of horological balance springs ( 2 a ).

10 . The method according to claim 1 , wherein at least one of the systems ( 3 ) comprises an oscillating element ( 10 ) that is in a shape of a tuning fork.

11 . The method according to claim 1 ,
wherein the systems ( 3 ) comprise a plurality of first systems ( 3 ), including the first system ( 3 ), and a plurality of second systems ( 3 ), including the second system ( 3 ), and wherein forming, in the wafer ( 1 ), the systems ( 3 ) comprises:
arranging the plurality of first systems ( 3 ) closer to the first horological balance spring ( 2 b , 2 c ) than to any other of the horological balance springs ( 2 b , 2 c ), and
arranging the plurality of second systems ( 3 ) closer to the second horological balance spring ( 2 b , 2 c ) than to any other of the horological balance springs ( 2 b , 2 c ).

12 . The method according to claim 11 ,
wherein the first systems ( 3 ) and the second systems ( 3 ) each comprise a plurality of oscillating elements ( 10 ).

Assignees

• Nivarox Far Sa

Inventors

• Chassin Geoffrey
• Cusin Pierre

Classifications

• Y10T29/49609

  Spring making · CPC title

• Y10T29/49579

  Watch or clock making · CPC title

• G04D7/10

  for hairsprings {of balances} · CPC title

• G04B17/066 Primary

  Manufacture of the spiral spring (locking of the spiral spring by the regulating lever G04B18/026; spiral spring with temperature compensation G04B17/227; fixation of the spiral spring on the collet G04B17/32; mainspring G04B1/14) · CPC title

• G04D3/0069

  for working with non-mechanical means, e.g. chemical, electrochemical, metallising, vapourising; with electron beams, laser beams · CPC title