EP2990883A1 - Clockwork balance wheel-hairspring assembly - Google Patents

Abstract

The invention relates to a balance-balance system comprising a balance oscillating around a balance shaft and a spiral of which an inner turn is fixed to the balance shaft or to a ferrule mounted integral with the shaft and one of which outer turn is fixed to a pin integral with a bridge, the balance having a hub, a serge, an arm connecting the hub to the serge, a front face having a recess and a rear face, the arm having a housing for receiving and maintaining a feeder, and the hairspring being mounted facing the front face of the balance. According to the invention, the weight is mounted on the arm on the side of the rear face of the balance, the distance between the bottom of the hole of the front face of the balance and the balance is in a predetermined range between 0.05mm and 1.50mm.

Description

Field of the invention

The invention relates to a sprung-balance assembly whose balance has means for adjusting the inertia.

The invention also relates to a watch movement comprising such a system and a timepiece equipped with such a movement.

Background of the invention

It is known from the patent CH 705 238 a pinch weight balance allowing adjustment of inertia and / or balancing. The balance has two arms each having a housing for receiving and pinching in position of a rod of a feeder. Depending on the direction of mounting of the balance in the movement it may be that access to the flyweights positioned on the underside of the balance is difficult or impossible and then requires disassembly. In addition, in the case where the distance between the peak and the inner diameter of the serge is too low the flyweights can hit the peak, thus harming the smooth operation of the balance.

Summary of the invention

The invention particularly aims to overcome the various disadvantages of these known techniques.

More specifically, an object of the invention is to provide a pendulum for obtaining a compact watch movement.

Another object of the invention is to provide a balance spring system allowing easy access to the flyweights for adjusting the inertia after the casing.

The invention also aims, at least in a particular embodiment, to provide a balance spring system that is simple to implement and inexpensive.

These objectives, as well as others which will appear more clearly later, are achieved according to the invention with the aid of a balance-balance system comprising at least one balance oscillating about a pivot axis via a control shaft. balance wheel mounted between a plate and a bridge (9) and aligned on said pivot axis, and at least one spiral of which an inner turn is fixed to said balance shaft or to a ferrule mounted integral with said balance shaft and an outer turn of which is fixed to a pin integral with the bridge carrying said shaft, said balance having a balance hub, a serge, at least one arm connecting said hub to said serge, a front face having a recess and a rear face, said at least one arm comprising a housing for receiving and maintaining a feeder, and said hairspring being mounted facing the front face of the balance.

According to the invention, said flyweight is mounted on the side of the rear face of the balance, on said at least one arm of said balance, and in that the distance between the bottom of the core of the front face of the balance and the balance is within a predetermined range of 0.05mm to 1.50mm

• la valeur de l'intervalle prédéterminé est comprise entre 0.10mm et 0.70mm ;
• la au moins une masselotte comprend une tête et une tige, la tête reposant contre la face arrière dudit balancier, et la tige reposant dans le logement ;
• la tête de la au moins une masselotte comprend des moyens de manipulation de manière à régler la au moins une masselotte depuis la face arrière du balancier ;
• la tige est affleurante avec le fond de la noyure de la face avant du balancier de manière à ce que la noyure ne présente pas d'élément saillant ;
• le diamètre de la tige de la au moins une masselotte est au moins égal à la largeur du logement ;
• l'au moins un bras, la serge et le moyeu forment un élément monobloc.

According to other advantageous variants of the invention:

• the value of the predetermined interval is between 0.10mm and 0.70mm;
• the at least one flyweight comprises a head and a rod, the head resting against the rear face of said balance, and the rod resting in the housing;
• the head of the at least one feeder comprises manipulation means so as to adjust the at least one feeder from the rear face of the balance;
• the stem is flush with the bottom of the hole of the front face of the beam so that the hole does not have a projecting element;
• the diameter of the rod of the at least one feeder is at least equal to the width of the housing;
• the at least one arm, the serge and the hub form a monobloc element.

The invention also relates to a watch movement comprising a balance-balance oscillator system according to the invention.

The invention also relates to a timepiece comprising a watch movement according to the invention.

Thus, the object of the present invention, by its different functional and structural aspects described above, makes it possible to obtain a clockwork movement comprising a balance-spring system whose access to the means for adjusting the inertia is particularly easy. .

Brief description of the drawings

• la figure 1a est une vue de dessous d'un balancier conforme à l'invention ;
• la figure 1b est une vue en coupe selon la ligne A-A de la figure 1 d'un balancier conforme à l'invention ;
• la figure 2 est une vue en coupe selon la ligne A-A de la figure 1 d'un système balancier-spiral conforme à l'invention équipant un mouvement horloger.

Other features and advantages of the invention will appear more clearly on reading the following description of a particular embodiment of the invention, given by way of a simple illustrative and nonlimiting example, and the appended figures, among which: :

• the figure 1a is a bottom view of a balance according to the invention;
• the figure 1b is a sectional view along line AA of the figure 1 a balance according to the invention;
• the figure 2 is a sectional view along line AA of the figure 1 a balance-balance system according to the invention equipping a watch movement.

Detailed Description of the Preferred Embodiments

A sprung balance assembly according to an exemplary embodiment will now be described in the following with reference to Figures 1a, 1b and 2 .

The invention thus relates to a sprung balance-balance system, intended to be incorporated in an oscillating mechanism within a watch movement, and comprising at least one rocker 1 oscillating about a pivot axis P via a balance shaft 40 aligned on the axis P and at least one hairspring 2.

As can be seen at figure 2 , the rocker shaft 40 is mounted between a plate 13 and a bridge 9, the rocker shaft 40 having at each of its ends a tapered pivot 41 to allow the rocker shaft 40 to pivot about the axis pivoting P by limiting the friction. An inner turn (not visible in the figures) of the hairspring 2 is fixed to the balance shaft 40 or to a shell 7 which can be integral with the hairspring 2 mounted integral with the balance shaft 40 and an outer turn 21 of the hairspring 2 is fixed to a stud 8 secured to a bridge 9.

The invention is described here in the particular case of a single balance spring and single spiral regulator member, the skilled person will extrapolate the invention to the case of several rockers and / or several spirals.

As can be seen in the figures, the balance 1 comprises a hub 3 carrying the balance shaft 40, a serge 4, at least one arm 5 connecting the hub 3 to the serge 4, a front face 10 having a core 11 and a flat rear face 12 which can also be embedded. The arm 5 comprises a housing 6 for receiving and holding at least one feeder 30, and the hairspring 2 is mounted opposite the front face 10 of the rocker 1 receiving the casing 11.

As can be seen on the Figures 1a and 1b , the rocker 1 comprises rigid parts constituted by the hub 3, the serge 4, and the arm 5 connecting the serge 4 to the hub 2. The housing 6 is delimited, on the one hand by a rigid portion of the balance 1, and on the other hand a portion 61 elastically deformable.

The arm 5 comprises a housing 6 for receiving and pinching in the position of a rod 32 of a flyweight 30. This weight 30 comprises a head 31 having handling means such as a control profile 33 arranged to cooperate with a tool, such as a screwdriver. Thus, the weight 30 can be adjusted from said rear face 12 of the balance 1. The rod 32 of the weight 30 extends the head 31, which is of greater diameter than that of the rod 32.

The diameter of the rod 32 of the weight 30 is chosen greater than the width of the housing 6 so that the rod 32 is retained by the portion 61 elastically deformable, the portion 61 exerting a restoring force.

Advantageously, the length of the rod 32 does not exceed the thickness of the arm 5, so that the rod 32 is not protruding and thus optimize the arrangement of parts within the movement to gain compactness.

This simple configuration of a feeder 30 consisting solely of the head 31 and the rod 32 is favorable for mounting the feeder on the balance 1 from the bottom of the latter.

The weight 30, once pinched in the housing 6, is angularly adjustable by means of a tool without being disturbed by the spiral 2 or by the limited space available. The weight 30 comprises an unbalance made by means of a flat portion 34 made on the head 31, as visible on the figure 1 a, to allow the inertia adjustment of the balance 1.

According to the invention, the weight 30 is mounted on the side of the rear face 12 of the balance 1, the head 31 resting against the rear face 12 of the balance 1 under the arm 5, the distance between the bottom of the face of the yoke before 10 of the balance 1 and the balance spring 2 is in a range V predetermined between 0.05mm and 1.50mm. More preferably, the predetermined interval V is between 0.10mm and 0.70mm. Such an arrangement provides a compact arrangement and thus reduce the size of the watch movement.

In a particularly advantageous manner, the rod 32 is flush with the bottom of the core 11 of the front face 10 of the rocker 1 so that the core 11 does not have a projecting element, the stud 8 can then be arranged at most near the serge 4, the piton 8 can even be closer to the bottom of the hole 11.

The arm 5, the serge 4 and the hub 3 form a single piece element, the rocker 1 can be made of a metal material.

The invention also relates to a watch movement and a timepiece equipped with a balance spring system according to the invention.

Thanks to these different aspects of the invention, there is a compact balance-balance system to reduce the thickness of the watch movement and implicitly the thickness of the watch case so as to provide a relatively thin watch.

Of course, the present invention is not limited to the illustrated example and is susceptible of various variations and modifications that will occur to those skilled in the art.

NOMENCLATURE

• 1. Pendulum,
• 2. Spiral,
• 21. Outside spire,
• 3. Hub,
• 4. Serge,
• 5. Arms,
• 6. Housing,
• 61. Elastic portion,
• 7. Ferrule,
• 8. Piton,
• 9. Bridge,
• 10. Front side,
• 11. Noyure,
• 12. Back side,
• 13. Platinum,
• 30. Masselotte,
• 31. Head,
• 32. Stem,
• 33. Adjustment profile
• 34. Flats,
• 40. Balance shaft,
• 41. Swivel,
• P. Pivot axis,
• V. predetermined value.

Claims (9)

System (100) sprung balance comprising at least one balance (1) oscillating about a pivot axis (P) via a balance shaft (40) mounted between a plate (13) and a bridge (9) and aligned with said pivot axis (P), and at least one spiral (2) of which an inner turn is fixed to said balance shaft (40) or a ferrule (7) mounted integral with said balance shaft (40) and of which an outer turn is fixed to a pin (8) secured to said bridge (9) carrying said balance shaft (40), said rocker (1) having a hub (3) balance (1), a serge (4), at least one arm (5) connecting said hub (3) to said seam (4), a front face (10) having a recess (11) and a rear face (12), said at least one arm (5) having a recess (6) for receiving and maintaining at least one feeder (30), and said hairspring (2) being mounted facing the front face (10) of the balance,
characterized in that said at least one flyweight (30) is mounted on the rear face (12) of the balance (1), on said at least one arm (5) of said balance (1), and in that the distance between the bottom of the core of said front face (10) of said beam (1) and said spring (2) is in a predetermined range (V) between 0.05mm and 1.50mm. The system (100) of claim 1, wherein the value of said predetermined interval is between 0.10mm and 0.70mm. System (100) according to claim 1 or 2, wherein said at least one feeder (30) comprises a head (31) and a rod (32), said head (31) resting against the rear face (12) of said balance ( 1), and said rod (32) resting in said housing (6). System (100) according to claim 1 or 2, wherein said head (31) of said at least one feeder (30) comprises handling means for adjusting said at least one feeder (30) from said rear face (12). ) of the balance (1). The system (100) of claim 3, wherein said rod (32) is flush with the bottom of the nose (11) of the front face (10) said balance (1) so that the hole (11) does not have a projecting element. System (100) according to claim 3 or 4, wherein the diameter of said rod (32) of said at least one feeder (30) is at least equal to the width of said housing (6). System (100) according to any one of claims 1 to 6, wherein said at least one arm (5), said serge (4) and said hub (3) form a one-piece element. Clockwork movement comprising a balance spring system (100) according to one of claims 1 to 7. Timepiece comprising a movement according to claim 8.

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