EP0911707B1 - Method for manufacturing a balance hairspring for a clockwork and hairspring obtained thereby. - Google Patents

Method for manufacturing a balance hairspring for a clockwork and hairspring obtained thereby. Download PDF

Info

Publication number
EP0911707B1
EP0911707B1 EP97118332A EP97118332A EP0911707B1 EP 0911707 B1 EP0911707 B1 EP 0911707B1 EP 97118332 A EP97118332 A EP 97118332A EP 97118332 A EP97118332 A EP 97118332A EP 0911707 B1 EP0911707 B1 EP 0911707B1
Authority
EP
European Patent Office
Prior art keywords
balance
spring
zone
heat treatment
manufacturing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP97118332A
Other languages
German (de)
French (fr)
Other versions
EP0911707A1 (en
Inventor
Philippe Marmy
Eric Favre
Christoph Schlenker
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ETA SA Manufacture Horlogere Suisse
Original Assignee
ETA SA Manufacture Horlogere Suisse
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ETA SA Manufacture Horlogere Suisse filed Critical ETA SA Manufacture Horlogere Suisse
Priority to EP97118332A priority Critical patent/EP0911707B1/en
Publication of EP0911707A1 publication Critical patent/EP0911707A1/en
Application granted granted Critical
Publication of EP0911707B1 publication Critical patent/EP0911707B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B17/00—Mechanisms for stabilising frequency
    • G04B17/04—Oscillators acting by spring tension
    • G04B17/06—Oscillators with hairsprings, e.g. balance
    • G04B17/066—Manufacture of the spiral spring

Definitions

  • the present invention relates to a method of manufacturing a pendulum balance spring for a watch movement and more particularly to such a method making it possible to reduce the sensitivity of the spiral to impacts.
  • the invention also relates to a spiral obtained in particular according to this method.
  • the accuracy of the running of a mechanical movement watch depends essentially on the isochronism of its regulating organ.
  • the latter is formed by the sprung balance assembly.
  • the balance is generally a steering wheel with two or three arms and the hairspring is a long spiral wound metal spring, for example flat or cylindrical whose turns are equidistant.
  • the hairspring is fixed to the balance by its inner end by means of a ring called ferrule, which is intended to be adjusted on the balance shaft, while the outer end of the hairspring is attached to a part called piton, fixed on the pendulum bridge.
  • ferrule ring called ferrule
  • this regulating member is associated with a racket which is an element carrying pins between which the outer turn passes before the peak.
  • the racket makes it possible to modify the operation of the watch by lengthening or shortening the active length of the hairspring by acting on the points of contact of the outer turn with the pins.
  • the main purpose of the invention is therefore to overcome the drawbacks of the above-mentioned prior art by providing a method of manufacturing a balance spring which gives the spring a better impact resistance.
  • the object of the invention is also to provide a balance spring that is not very sensitive to shocks without considerably increasing its cost price.
  • the invention relates to a method of manufacturing a balance spring balance of a watch movement as defined in claim 1 of the patent.
  • This method makes it possible to release the internal stresses of the material resulting from cold deformation of the hairspring and in particular of the portion of the outer turn located in the vicinity of the racket pin and the pin integral with the balance bridge, so that the resistance to permanent deformation of the hairspring following a shock is improved.
  • the spiral is made of an alloy steel
  • the step of the second heat treatment consists of heating said zone to a temperature of between 500 and 650 ° C and preferably between 510 and 550 ° C.
  • the zone which undergoes the second heat treatment extends to from the attachment point of the stud on the outer turn and inward of the spiral on a circular arc of less than 200 ° and preferably on an arc less than 140 °.
  • the transition zone between the outer turn and the previous turn will be included in the zone undergoing the second heat treatment.
  • the invention also relates to a balance spring balance of a watch movement as defined in claim 7 of the patent.
  • the Vickers hardness of the outer end zone is 10% less than the hardness of the remainder of the hairspring.
  • a hairspring 1 mounted on a rocker 2 and intended to form the regulating member of a clockwork movement (not shown), ie the member which determines the unwinding speed of the gear train leading to the needles of time and of which only the wheel 4 and the exhaust pinion 6 are visible at the figure 1 .
  • the rocker 2 is formed of a three-armed flywheel 8.
  • the spiral 1 is a wire or a metal strip wound in the form of a spiral.
  • the metal used to manufacture the hairspring is preferably an alloy steel, for example a ferronickel steel, and that after shaping, the entire hairspring 1 undergoes a first conventional heat treatment to fix the final shape and the elasticity characteristics. required of the hairspring.
  • the hairspring 1 comprises an inner end 10 through which it is fixed to a shell 12 fitted on a balance shaft 14.
  • the hairspring 1 comprises an incomplete outer turn 16, defining an outer end zone, which ends with an end 18 attached to a stud 20.
  • the stud 20 is secured to a balance bridge 22 fixed to the plate (not shown) of the movement.
  • Pins 24 of the racket 26, between which the outer turn 16 passes before being fixed to the stud 20 are also shown in the figure.
  • the outer turn 16 is connected to the previous turn 26 by a transition zone 28 forming a step or step extending substantially radially inward.
  • the radial distance D between the outer turn 16 and the previous turn 26 is equal to several steps of the spiral at rest, of course this distance may vary depending on the types of spiral.
  • the hairspring 1 is subjected during its manufacture to a second localized heat treatment step. More particularly, this additional heat treatment consists of subjecting at least the outer turn 16 or outer end zone of the hairspring 1 to heating at a temperature of between 500 and 650 ° C. and preferably between 510 and 550 ° C.
  • the treated portion 16 of the hairspring 1 is subjected to heating for a time sufficient for the aforementioned temperatures to be reached at heart of this portion. Given the small thickness of the wire or the band forming the hairspring (generally between 2.5 to 4.5 hundredths of a millimeter) the heating time is very short. After heating, the treated turn 16 is cooled in air to room temperature.
  • the part of the spiral 1 which undergoes the heat treatment comprises the transition zone 28 and will generally extend inwardly of the spiral 1 beyond the outer turn 16 on a arc of less than 200 ° and preferably on a circular arc of less than 140 ° from the attachment point 18 of the peak on the outer turn 16.
  • the heat source for carrying out the heat treatment advantageously comprises a laser beam.
  • the use of a laser beam for the heating operation has the particular advantage of being able to precisely control the portion of the hairspring to be heated by controlling the focusing point of the beam.
  • the laser beam can be easily applied in the form of laser pulses of very short durations in the vicinity of the portion to be heated at successive points along this portion as is symbolized in the figure by dashed circles.
  • the duration of each laser pulse is of the order of 0.6 to 0.7 ms.
  • the laser beam is preferably applied in the region adjacent to the portion to be treated of the spiral which is on the outside of the hairspring 1.
  • heating means that a laser beam can be considered by the skilled person to achieve this heat treatment.
  • a visible or invisible light source such as a scanning infrared beam, a high frequency induction system, a directed micro-torch or any other means for obtaining localized heating.
  • a visible or invisible light source such as a scanning infrared beam, a high frequency induction system, a directed micro-torch or any other means for obtaining localized heating.
  • the duration of the heating can vary according to the heating means used
  • the Applicant has found that the end zone of the hairspring which has undergone the heat treatment described above has a hardness lower than that of the remainder of the hairspring, the Vickers hardness measured in this outer end zone being lower than that of the remainder of the hairspring. approximately 10% to 15% to the hardness of the remainder of the hairspring.
  • the Vickers hardnesses measured on the parts of the untreated hairspring varied from 385 to 395 HV 0.025 and the Vickers hardnesses measured on the parts treated according to the invention of the same hairspring ranged from 360 to 375 HV 0.025 .

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Springs (AREA)

Description

La présente invention concerne un procédé de fabrication d'un spiral de balancier pour mouvement d'horlogerie et plus particulièrement un tel procédé permettant de diminuer la sensibilité du spiral aux chocs. L'invention concerne également un spiral obtenu notamment selon ce procédé.The present invention relates to a method of manufacturing a pendulum balance spring for a watch movement and more particularly to such a method making it possible to reduce the sensitivity of the spiral to impacts. The invention also relates to a spiral obtained in particular according to this method.

L'exactitude de la marche d'une montre à mouvement mécanique dépend essentiellement de l'isochronisme de son organe régulateur. Ce dernier est formé par l'ensemble balancier-spiral. Le balancier est généralement un volant à deux ou trois bras et le spiral est un long ressort de métal enroulé en forme de spirale, par exemple plat ou cylindrique dont les spires sont équidistantes. Le spiral est fixé au balancier par son extrémité intérieure par l'intermédiaire d'une bague appelée virole, qui est destinée à être ajustée sur l'axe de balancier, alors que l'extrémité extérieure du spiral est attachée à une pièce appelée piton, fixée sur le pont de balancier. Un exemple de ce dispositif est donné dans le document CH 636 992 ou dans le document CH 474 099 . Généralement, à cet organe régulateur est associée une raquette qui est un élément portant des goupilles entre lesquelles passe la spire extérieure avant le piton. La raquette permet de modifier la marche de la montre en allongeant ou en raccourcissant la longueur active du spiral en agissant sur les points de contact de la spire extérieure avec les goupilles.The accuracy of the running of a mechanical movement watch depends essentially on the isochronism of its regulating organ. The latter is formed by the sprung balance assembly. The balance is generally a steering wheel with two or three arms and the hairspring is a long spiral wound metal spring, for example flat or cylindrical whose turns are equidistant. The hairspring is fixed to the balance by its inner end by means of a ring called ferrule, which is intended to be adjusted on the balance shaft, while the outer end of the hairspring is attached to a part called piton, fixed on the pendulum bridge. An example of this device is given in the document CH 636 992 or in the document CH 474,099 . Generally, this regulating member is associated with a racket which is an element carrying pins between which the outer turn passes before the peak. The racket makes it possible to modify the operation of the watch by lengthening or shortening the active length of the hairspring by acting on the points of contact of the outer turn with the pins.

La sensibilité aux chocs de cet organe régulateur est depuis longtemps un problème qui est resté sans solution satisfaisante. En effet tout choc que subit la montre peut entraîner des déformations des spires, conduisant à une perte de leur concentricité, voire, pour l'avant-dernière spire extérieure, à un contact avec le piton. Dans tous les cas il s'ensuit d'importantes perturbations de la marche et de l'amplitude du balancier et par conséquent une perte de ses qualités réglantes.The shock sensitivity of this regulator has long been a problem that has remained unsolved. In fact any shock that the watch undergoes may cause deformations of the turns, leading to a loss of their concentricity, or, for the penultimate outer turn, to a contact with the peak. In any case, it results in major disturbances of the walking and amplitude of the pendulum and consequently a loss of its regulating qualities.

L'invention a donc pour but principal de remédier aux inconvénients de l'art antérieur susmentionné en fournissant un procédé de fabrication d'un spiral de balancier qui confère au spiral une résistance aux chocs améliorée. L'invention a également pour but de fournir un spiral de balancier peu sensible aux chocs sans en augmenter considérablement le prix de revient.The main purpose of the invention is therefore to overcome the drawbacks of the above-mentioned prior art by providing a method of manufacturing a balance spring which gives the spring a better impact resistance. The object of the invention is also to provide a balance spring that is not very sensitive to shocks without considerably increasing its cost price.

A cet effet l'invention a pour objet un procédé de fabrication d'un spiral de balancier d'un mouvement d'horlogerie tel que défini à la revendication 1 du brevet. Ce procédé permet de relâcher les contraintes internes du matériau qui résultent de déformation à froid du spiral et en particulier de la portion de la spire extérieure se trouvant au voisinage de la goupille de raquette et du piton solidaire du pont de balancier, de sorte que la résistance à la déformation permanente du spiral à la suite d'un choc est améliorée.For this purpose the invention relates to a method of manufacturing a balance spring balance of a watch movement as defined in claim 1 of the patent. This method makes it possible to release the internal stresses of the material resulting from cold deformation of the hairspring and in particular of the portion of the outer turn located in the vicinity of the racket pin and the pin integral with the balance bridge, so that the resistance to permanent deformation of the hairspring following a shock is improved.

Selon un mode de réalisation préféré, le spiral est réalisé en un acier allié l'étape du deuxième traitement thermique consiste à chauffer ladite zone à une température comprise entre 500 et 650°C et de préférence entre 510 et 550°C.According to a preferred embodiment, the spiral is made of an alloy steel the step of the second heat treatment consists of heating said zone to a temperature of between 500 and 650 ° C and preferably between 510 and 550 ° C.

On comprendra que les températures de traitement varient dans les gammes susmentionnées en fonction de la composition de l'alliage du ressort spiral considéré.It will be understood that the processing temperatures vary within the aforementioned ranges depending on the composition of the alloy of the spiral spring considered.

Selon une caractéristique préférée de l'invention, la zone qui subit le deuxième traitement thermique s'étend, à partir du point de fixation du piton sur la spire extérieure et vers l'intérieur du spiral sur un arc de cercle inférieur à 200° et de préférence sur un arc de cercle inférieur à 140°.According to a preferred characteristic of the invention, the zone which undergoes the second heat treatment extends to from the attachment point of the stud on the outer turn and inward of the spiral on a circular arc of less than 200 ° and preferably on an arc less than 140 °.

En tout état de cause la zone de transition entre la spire extérieure et la spire précédente sera comprise dans la zone qui subit le deuxième traitement thermique.In any case, the transition zone between the outer turn and the previous turn will be included in the zone undergoing the second heat treatment.

L'invention a également pour objet un spiral de balancier d'un mouvement d'horlogerie tel que défini à la revendication 7 du brevet.The invention also relates to a balance spring balance of a watch movement as defined in claim 7 of the patent.

Selon un mode préféré de l'invention, la dureté Vickers de la zone d'extrémité extérieure est inférieure de 10% à la dureté du reste du spiral.According to a preferred embodiment of the invention, the Vickers hardness of the outer end zone is 10% less than the hardness of the remainder of the hairspring.

D'autres caractéristiques et avantages de l'invention apparaîtront plus clairement à lecture de la description suivante d'un mode de réalisation de l'invention, donné à titre purement illustratif et non limitatif, cette description étant faite en liaison avec les dessins annexés dans lesquels :

  • la figure 1 est une vue en perspective d'un ensemble régulateur comprenant notamment un spiral selon l'invention; et
  • la figure 2 est une vue de dessus d'un spiral selon l'invention monté sur son balancier.
Other features and advantages of the invention will appear more clearly on reading the following description of an embodiment of the invention, given for purely illustrative and non-limiting purposes, this description being given in conjunction with the accompanying drawings in FIG. which :
  • the figure 1 is a perspective view of a regulator assembly comprising in particular a spiral according to the invention; and
  • the figure 2 is a top view of a hairspring according to the invention mounted on its balance.

A la figure 1, on voit un spiral 1 monté sur un balancier 2 et destiné à former l'organe régulateur d'un mouvement d'horlogerie (non représenté), c'est à dire l'organe qui détermine la vitesse de déroulement du rouage conduisant aux aiguilles d'indication de l'heure et dont seuls la roue 4 et le pignon 6 d'échappement sont visibles à la figure 1.To the figure 1 , we see a hairspring 1 mounted on a rocker 2 and intended to form the regulating member of a clockwork movement (not shown), ie the member which determines the unwinding speed of the gear train leading to the needles of time and of which only the wheel 4 and the exhaust pinion 6 are visible at the figure 1 .

Dans l'exemple représenté le balancier 2 est formé d'un volant à trois bras 8. Le spiral 1 est un fil ou une bande métallique enroulée en forme de spirale.In the example shown the rocker 2 is formed of a three-armed flywheel 8. The spiral 1 is a wire or a metal strip wound in the form of a spiral.

On notera que le métal utilisé pour fabriquer le spiral est de préférence un acier allié, par exemple un acier ferronickel, et qu'après conformation, le spiral 1 entier subit un premier traitement thermique classique pour fixer la forme définitive et les caractéristiques d'élasticité requises du spiral.It should be noted that the metal used to manufacture the hairspring is preferably an alloy steel, for example a ferronickel steel, and that after shaping, the entire hairspring 1 undergoes a first conventional heat treatment to fix the final shape and the elasticity characteristics. required of the hairspring.

Le spiral 1 comprend une extrémité intérieure 10 par laquelle il est fixé à une virole 12 ajustée sur un axe de balancier 14. Le spiral 1 comprend une spire extérieure 16 incomplète, définissant une zone d'extrémité extérieure, qui se termine par une extrémité 18 attachée à un piton 20. Le piton 20 est solidaire d'un pont de balancier 22 fixé à la platine (non représentée) du mouvement .The hairspring 1 comprises an inner end 10 through which it is fixed to a shell 12 fitted on a balance shaft 14. The hairspring 1 comprises an incomplete outer turn 16, defining an outer end zone, which ends with an end 18 attached to a stud 20. The stud 20 is secured to a balance bridge 22 fixed to the plate (not shown) of the movement.

La fixation des extrémités intérieure 10 et extérieure 18 du spiral 1 est classique et bien connue de l'homme de métier et ne sera par conséquent pas décrite plus en détail.Fixing the inner and outer ends 18 of the hairspring 1 is conventional and well known to those skilled in the art and will therefore not be described in more detail.

On a également représenté à la figure des goupilles 24 de la raquette 26, entre lesquelles passe la spire extérieure 16 avant d'être fixée au piton 20.Pins 24 of the racket 26, between which the outer turn 16 passes before being fixed to the stud 20 are also shown in the figure.

La spire extérieure 16 est reliée à la spire précédente 26 par une zone de transition 28 formant une marche d'escalier ou gradin s'étendant sensiblement radialement vers l'intérieur. Dans l'exemple représenté, la distance radiale D entre la spire extérieure 16 et la spire précédente 26 est égale à plusieurs pas du spiral au repos, bien entendu cette distance peut varier selon les types de spiraux.The outer turn 16 is connected to the previous turn 26 by a transition zone 28 forming a step or step extending substantially radially inward. In the example shown, the radial distance D between the outer turn 16 and the previous turn 26 is equal to several steps of the spiral at rest, of course this distance may vary depending on the types of spiral.

Selon l'invention, le spiral 1 est soumis au cours de sa fabrication à une deuxième étape de traitement thermique localisé. Plus particulièrement, ce traitement thermique supplémentaire consiste à soumettre au moins la spire extérieure 16 ou zone d'extrémité extérieure du spiral 1 à un chauffage à une température comprise entre 500 et 650°C et de préférence comprise entre 510 et 550°C. De façon avantageuse, la portion traitée 16 du spiral 1 est soumise à un chauffage pendant un temps suffisant pour que les températures susmentionnées soient atteintes au coeur de cette portion. Compte tenu des faibles épaisseurs du fil ou de la bande formant le spiral (comprise généralement entre 2,5 à 4,5 centièmes de mm) le temps de chauffage est très court. Après le chauffage, la spire traitée 16 est refroidie à l'air jusqu'à température ambiante.According to the invention, the hairspring 1 is subjected during its manufacture to a second localized heat treatment step. More particularly, this additional heat treatment consists of subjecting at least the outer turn 16 or outer end zone of the hairspring 1 to heating at a temperature of between 500 and 650 ° C. and preferably between 510 and 550 ° C. Advantageously, the treated portion 16 of the hairspring 1 is subjected to heating for a time sufficient for the aforementioned temperatures to be reached at heart of this portion. Given the small thickness of the wire or the band forming the hairspring (generally between 2.5 to 4.5 hundredths of a millimeter) the heating time is very short. After heating, the treated turn 16 is cooled in air to room temperature.

Selon un mode de réalisation préféré du procédé de l'invention, la partie du spiral 1 qui subit le traitement thermique comprend la zone de transition 28 et s'étendra généralement vers l'intérieur du spiral 1 au delà de la spire extérieure 16 sur un arc de cercle inférieur à 200° et de préférence sur un arc de cercle inférieur à 140° à partir du point de fixation 18 du piton sur la spire extérieure 16.According to a preferred embodiment of the method of the invention, the part of the spiral 1 which undergoes the heat treatment comprises the transition zone 28 and will generally extend inwardly of the spiral 1 beyond the outer turn 16 on a arc of less than 200 ° and preferably on a circular arc of less than 140 ° from the attachment point 18 of the peak on the outer turn 16.

La source de chaleur pour réaliser le traitement thermique comprend de façon avantageuse un faisceau laser. L'utilisation d'un faisceau laser pour l'opération de chauffage présente notamment l'avantage de pouvoir contrôler avec précision la portion du spiral à chauffer en contrôlant le point de focalisation du faisceau. En particulier, le faisceau laser peut être aisément appliqué sous forme d'impulsions laser de très courtes durées au voisinage de la portion à chauffer en des points successifs le long de cette portion comme cela est symbolisé à la figure par des cercles en pointillés. Typiquement la durée de chaque impulsion laser est de l'ordre de 0,6 à 0,7 ms. On notera à ce propos que le faisceau laser est appliqué de préférence dans la région voisine de la portion à traiter du spiral qui se trouve du côté de l'extérieur du spiral 1.The heat source for carrying out the heat treatment advantageously comprises a laser beam. The use of a laser beam for the heating operation has the particular advantage of being able to precisely control the portion of the hairspring to be heated by controlling the focusing point of the beam. In particular, the laser beam can be easily applied in the form of laser pulses of very short durations in the vicinity of the portion to be heated at successive points along this portion as is symbolized in the figure by dashed circles. Typically the duration of each laser pulse is of the order of 0.6 to 0.7 ms. It should be noted in this connection that the laser beam is preferably applied in the region adjacent to the portion to be treated of the spiral which is on the outside of the hairspring 1.

Il va de soi que d'autres moyens de chauffage qu'un faisceau laser peuvent être envisagés par l'homme de métier pour réaliser ce traitement thermique. En particulier on peut également prévoir une source de lumière visible ou invisible tel qu'un faisceau infrarouge à balayage, un système à induction à haute fréquence, un micro-chalumeau dirigé ou tout autre moyen permettant d'obtenir un chauffage localisé. On comprendra bien entendu que la durée du chauffage peut varier en fonction des moyens de chauffage utilisésIt goes without saying that other heating means that a laser beam can be considered by the skilled person to achieve this heat treatment. In particular, it is also possible to provide a visible or invisible light source such as a scanning infrared beam, a high frequency induction system, a directed micro-torch or any other means for obtaining localized heating. We will understand understood that the duration of the heating can vary according to the heating means used

Pour des raisons pratiques, il est avantageux de monter le spiral 1 sur le balancier, sans toutefois monter le piton 18, préalablement au traitement thermique de la partie du spiral décrite plus haut. Il est bien entendu que l'inverse peut être envisagé et que ce traitement thermique peut être réalisé en fin de fabrication du spiral, celui-ci étant livré à l'horloger préformé et prétraité thermiquement dans la zone d'extrémité extérieure, en vue de son montage classique sur le balancier sans autre traitement ultérieur.For practical reasons, it is advantageous to mount the balance spring 1 on the balance, without however mounting the stud 18, prior to the heat treatment of the part of the spiral described above. It is understood that the opposite can be envisaged and that this heat treatment can be performed at the end of manufacture of the hairspring, the latter being delivered to the watchmaker preformed and thermally pretreated in the outer end zone, in order to its classic mounting on the balance without further processing.

Par ailleurs la demanderesse a constaté que la zone d'extrémité du spiral qui a subi le traitement thermique décrit ci-dessus présentait une dureté inférieure à celle du reste du spiral, la dureté Vickers mesurée dans cette zone d'extrémité extérieure étant inférieure d'approximativement 10% à 15% à la dureté du reste du spiral. A titre d'exemple, les duretés Vickers mesurées sur les parties du spiral non traitées variaient de 385 à 395 HV0,025 et les duretés Vickers mesurées sur les parties traitées selon l'invention du même spiral variaient de 360 à 375 HV0,025.Furthermore, the Applicant has found that the end zone of the hairspring which has undergone the heat treatment described above has a hardness lower than that of the remainder of the hairspring, the Vickers hardness measured in this outer end zone being lower than that of the remainder of the hairspring. approximately 10% to 15% to the hardness of the remainder of the hairspring. By way of example, the Vickers hardnesses measured on the parts of the untreated hairspring varied from 385 to 395 HV 0.025 and the Vickers hardnesses measured on the parts treated according to the invention of the same hairspring ranged from 360 to 375 HV 0.025 .

Claims (9)

  1. Method for manufacturing a balance-spring (1) for a clockwork movement wherein a spring is formed by winding, from a wire or metal strip, said spring including an inner end intended to be fixed to a balance and a outer end zone having been subjected to a cold deformation intended to be fixed to the balance-spring stud (20) and wherein the whole spring is subjected to a first heat treatment subsequent to the winding step of said wire, the method being characterised in that it further includes an additional step consisting in subjecting the outer end (16) zone having been subjected to a cold deformation to a second heat treatment aiming at releasing the internal stress of the material.
  2. Manufacturing method according to claim 1, characterised in that the balance-spring is made of an alloyed steel and in that the second heat treatment step consists in heating said zone to a temperature ranging between 500 and 650°C and preferably between 510 and 550°C.
  3. Manufacturing method according to claim 1 or 2, characterised in that said zone which undergoes the second heat treatment extends, from the point of fixation of the stud onto the outer turn and towards the interior of the balance-spring on an arc of a circle less than 200° and preferably on an arc of a circle less than 140°.
  4. Manufacturing method according to any of the preceding claims, characterised in that the second heat treatment is achieved using a laser beam.
  5. Manufacturing method according to claim 4, characterised in that the laser beam is applied in proximity to said zone, in successive points along said zone.
  6. Manufacturing method according to any of the preceding claims, characterised in that said balance-spring is mounted on a balance prior to said second heat treatment.
  7. Balance-spring (1) for a clockwork movement formed of a wire or a strip would in a spiral including an inner end intended to be fixed to a balance and an outer end zone intended to be fixed to a stud (20) in a removable manner, characterised in that the outer end zone has on the one hand a hardness less than that of the rest of the balance-spring and on the other hand relaxed internal stress.
  8. Balance-spring (1) according to claim 7, characterised in that the Vickers hardness of the outer end zone (16) is 10% to 15% less than the hardness of the rest of the balance-spring (1).
  9. Balance-spring according to any of the preceding claims, characterised in that it is made of a ferronickel steel.
EP97118332A 1997-10-22 1997-10-22 Method for manufacturing a balance hairspring for a clockwork and hairspring obtained thereby. Expired - Lifetime EP0911707B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP97118332A EP0911707B1 (en) 1997-10-22 1997-10-22 Method for manufacturing a balance hairspring for a clockwork and hairspring obtained thereby.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP97118332A EP0911707B1 (en) 1997-10-22 1997-10-22 Method for manufacturing a balance hairspring for a clockwork and hairspring obtained thereby.

Publications (2)

Publication Number Publication Date
EP0911707A1 EP0911707A1 (en) 1999-04-28
EP0911707B1 true EP0911707B1 (en) 2011-07-13

Family

ID=8227508

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97118332A Expired - Lifetime EP0911707B1 (en) 1997-10-22 1997-10-22 Method for manufacturing a balance hairspring for a clockwork and hairspring obtained thereby.

Country Status (1)

Country Link
EP (1) EP0911707B1 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ATE474250T1 (en) 2008-03-20 2010-07-15 Nivarox Sa MONOBLOCK DOUBLE SPIRAL AND ITS PRODUCTION PROCESS
DE202013007838U1 (en) 2013-09-04 2013-11-13 Nivarox-Far S.A. Spiral balance adjusting device for a mechanical watch
DE202013010213U1 (en) 2013-11-13 2014-02-05 Nivarox-Far S.A. Spiral balance adjusting device for a mechanical watch
EP2993531B1 (en) 2014-09-08 2021-03-31 Precision Engineering AG A method for forming a spring

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH474099A (en) * 1965-06-30 1969-07-31 Lip Sa Method and device for manufacturing a timing apparatus hairspring

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1475005A (en) * 1966-02-18 1967-03-31 Process for manufacturing metal wires and metal wires obtained by this process

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH474099A (en) * 1965-06-30 1969-07-31 Lip Sa Method and device for manufacturing a timing apparatus hairspring

Also Published As

Publication number Publication date
EP0911707A1 (en) 1999-04-28

Similar Documents

Publication Publication Date Title
CH692532A5 (en) A method of making a balance spring for a horological movement.
EP1655642B1 (en) Balance-spring resonator spiral
EP1818736A1 (en) Shockproof collet
EP3451076B1 (en) Stud-holder for a mechanical clockwork movement
EP2196868A1 (en) Hairspring with curve elevation made from a silicon-based material
EP2930572A2 (en) Clock set using an amorphous metal alloy
CH700260A2 (en) Regulating member for mechanical watch, has balance and hairspring forming balance-spiral assembly, where balance is machined using micro-fabrication process to allow machining dimensional tolerance in order of micron
EP1605323A2 (en) Spiral spring for mechanical clockwork
EP1637940B1 (en) Collet for timepieces
CH685660B5 (en) Timepiece provided with drive means forms by a piezoelectric motor.
EP0911707B1 (en) Method for manufacturing a balance hairspring for a clockwork and hairspring obtained thereby.
EP3182211A1 (en) Composite part with resilient means under stress
EP3252542B1 (en) Part for fastening a timepiece hairspring
EP2107433B1 (en) Method for assembling a part on an axle
EP1654597B1 (en) Thermally-compensated balance wheel
EP2917792B1 (en) Method for balancing a clockwork balance wheel-hairspring assembly
EP2753985B1 (en) Clock movement having a balance-wheel and hairspring
CH692535A5 (en) Shock resistant balance spring manufacturing method for clock work movements in watches
CH701155B1 (en) Balance spiral type mechanical oscillator for e.g. wrist watch, has balance and spiral, which are made of non-magnetic material such as diamond, where material possesses very low thermal expansion coefficient
EP3537228B1 (en) Device for adjusting the vibration frequency of a bell of a chiming mechanism
CH714107B1 (en) Piton holder for a mechanical watch movement.
CH716896A2 (en) Exhaust plate, timepiece sub-assembly and oscillator balance.
JP2020159780A (en) Timepiece component, manufacturing method therefor, movement, and timepiece
CH708210A2 (en) Snowshoeing with lockable pins.
EP4286961A1 (en) Timepiece regulator provided with a precision index-assembly

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): CH DE FR GB LI

AKX Designation fees paid

Free format text: CH DE FR GB LI

17P Request for examination filed

Effective date: 19991028

RIN1 Information on inventor provided before grant (corrected)

Inventor name: SCHLENKER, CHRISTOPH

Inventor name: FAVRE, ERIC

Inventor name: MARMY, PHILIPPE

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: ETA SA MANUFACTURE HORLOGERE SUISSE

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

RTI1 Title (correction)

Free format text: METHOD FOR MANUFACTURING A BALANCE HAIRSPRING FOR A CLOCKWORK AND HAIRSPRING OBTAINED THEREBY.

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

17Q First examination report despatched

Effective date: 20100420

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): CH DE FR GB LI

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 69740243

Country of ref document: DE

Effective date: 20110908

REG Reference to a national code

Ref country code: CH

Ref legal event code: NV

Representative=s name: ICB INGENIEURS CONSEILS EN BREVETS SA

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20120416

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20111022

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 69740243

Country of ref document: DE

Effective date: 20120416

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20111022

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 20160927

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20160921

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20160922

Year of fee payment: 20

REG Reference to a national code

Ref country code: DE

Ref legal event code: R071

Ref document number: 69740243

Country of ref document: DE

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL