EP2990882B1 - Balance with inertia adjustment. - Google Patents

Description

Field of the invention

The invention relates to a balance wheel with inertia adjustment having means for adjusting the inertia.

The invention also relates to a timepiece movement comprising such a system as well as a timepiece equipped with such a movement.

Invention background

It is known from the patent CH 705 238 a balance with pinched weights allowing adjustment of the inertia and / or balancing. The balance has two arms each comprising a housing for receiving and pinching in position a rod of a counterweight, the head of the counterweight resting against the face

The pendulum described above has several drawbacks. First of all, it should be mentioned that access to the flyweights can be difficult depending on the architecture of the movement and make the adjustment of the inertia complicated, which can lead to an increase in the adjustment costs. In addition, such a balance is relatively bulky, the head of the weights resting in the recess of the balance, which can lead to an increase in the thickness of the movement.

It is known, for example, from patents CH 698 024 and EP 2,410,386 such inertia adjustment pendulums having means for adjusting the inertia.

We also know of the patent EP 1,351,103 , a balance wheel with inertia adjustment for a clockwork movement in which the serge has recesses for receiving weights so that there is no protruding part. If adjustment of the pendulum is facilitated, the latter requires machining for the recesses which is relatively delicate, time-consuming and expensive.

Summary of the invention

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

More specifically, an objective of the invention is to provide a balance wheel with inertia adjustment making it possible to obtain a compact watch movement.

The invention also aims, at least in one particular embodiment, to provide a balance wheel with inertia adjustment which is simple to implement and inexpensive to produce.

These objectives, as well as others which will appear more clearly hereinafter, are achieved according to the invention using a balance wheel with inertia adjustment, for a timepiece, comprising a hub defining the axis of pivoting of said balance, a serge, a veil extending between a lower plane and an upper plane on either side of a median plane, said veil comprising at least one arm connecting said serge to said hub, said at least one arm comprising a housing configured to receive and hold in place at least one counterweight, said at least one counterweight having a front face and a rear face

According to the invention, said at least one counterweight is integrated in said arm of said pendulum, and said at least one counterweight comprises upper wings and lower wings intended to bear on either side of said arm respectively at the level of the lower plane and from the upper plane to hold said at least one counterweight axially in place.

The invention also relates to a balance wheel with inertia adjustment, for a timepiece, comprising a hub defining the pivot axis of said balance wheel, a twill, a web extending between a lower plane and an upper plane on the one hand and on the other from a median plane, said web comprising at least one arm connecting said serge to said hub, said at least one arm comprising a housing configured to receive and hold in place at least one counterweight, said at least one counterweight having a front face and a rear face, and being of cylindrical shape whose said faces form the bases of the cylinder, said at least one counterweight being integrated in said arm of said balance, so that said front face and rear face are substantially in said upper plane and said lower plane.

• la face avant et la face arrière de la au moins une masselotte sont en retrait de 0µm à 1mm par rapport au plan supérieur et au plan inférieur ;
• la face avant et la face arrière de la au moins une masselotte sont saillantes jusqu'à 0.6mm par rapport au plan supérieur et au plan inférieur ;
• la au moins une masselotte est dans le plan médian du voile ;
• le logement et la au moins une masselotte sont de forme complémentaire ;
• la au moins une masselotte est pincée avec un couple de retenue prédéterminé au sein du logement ;
• le bras présente une partie élastique s'étendant dans le plan médian, la partie élastique étant apte à se déformer lors du montage de la au moins une masselotte ;
• le logement comprend des arrêts au niveau du plan supérieur et du plan inférieur pour maintenir en place la au moins une masselotte ;
• la au moins une masselotte est chassée dans le logement du bras du balancier ;
• le bras et la serge ont la même épaisseur.

In accordance with other advantageous variants of the invention:

• the front face and the rear face of the at least one counterweight are set back from 0 μm to 1 mm relative to the upper plane and to the lower plane;
• the front face and the rear face of the at least one counterweight projecting up to 0.6mm with respect to the upper plane and the lower plane;
• the at least one flyweight is in the median plane of the veil;
• the housing and the at least one counterweight are of complementary shape;
• the at least one counterweight is pinched with a predetermined retaining torque within the housing;
• the arm has an elastic part extending in the median plane, the elastic part being able to deform during assembly of the at least one counterweight;
• the housing includes stops at the upper plane and the lower plane to hold in place the at least one counterweight;
• the at least one flyweight is driven into the housing of the balance arm;
• the arm and the serge have the same thickness.

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

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

Thus, the object of the present invention, by its various functional and structural aspects described above, makes it possible to obtain a relatively compact balance wheel with inertia adjustment.

Brief description of the drawings

• la figure 1 est une vue en perspective d'un balancier conforme à l'invention selon un premier mode de réalisation ;
• la figure 2 est une vue en perspective d'un balancier conforme à l'invention selon un deuxième mode de réalisation ;
• les figures 3 et 4 sont respectivement des vues en coupe d'un balancier selon les premier et deuxième modes de réalisation illustrés aux figures 1 et 2.

Other characteristics 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 simple illustrative and nonlimiting example, and of the appended figures, among which :

• the figure 1 is a perspective view of a pendulum according to the invention according to a first embodiment;
• the figure 2 is a perspective view of a pendulum in accordance with the invention according to a second embodiment;
• the figures 3 and 4 are respectively sectional views of a pendulum according to the first and second embodiments illustrated in Figures 1 and 2 .

Detailed description of preferred embodiments

A timepiece movement according to an exemplary embodiment will now be described in the following, referring jointly to figures 1, 2 , 3 and 4 .

The invention thus relates to a balance 1 with inertia adjustment, for a timepiece, comprising a hub 4 defining the pivot axis A of the balance 1, a clamp 10, a web 11 extending between a lower plane Pi and an upper plane Ps on either side of a median plane Pm, the web 11 comprising at least one arm 2 connecting the serge 10 to the hub 4, the at least one arm 2 comprising a housing 3 configured to receive and keep at least one counterweight in place 5.

Advantageously, the balance has a front face 12 having a recess 14 and a rear face 13 which can also be recessed.

According to a particular embodiment, the height of the twill 10 can be identical to the web 11, in this case the balance 1 does not have any drowning which makes it possible to obtain the most compact balance possible.

As illustrated, the pendulum 1 comprises four arms, forming a hub 4 at their intersection, the hub 4 being provided with an orifice 40 intended to receive a pendulum axis 41, the web 11 thus being formed by the four arms and the hub 4.

The serge 10 is circular in shape and has no projecting part, like the arms 2, so that the balance 1 is as compact as possible.

As can be seen in the figures, the counterweight 5 is of cylindrical shape and comprises a front face 52 and a rear face 53 and can have, according to one embodiment of the invention, upper 54 and lower 55 wings.

Advantageously, each counterweight 5 is pinched in a housing 3 in a service position where a median plane which it comprises coincides with the median plane Pm of the web 11.

The balance 1 comprises rigid parts constituted by the hub 4, the clamp 10, and the arms 2 connecting the clamp 10 to the hub 4. The housing 3 is delimited, on the one hand by a rigid part of the balance 1, and on the other hand an elastically deformable arm 20.

According to a particular embodiment of the invention, not illustrated in the figures, the stick 10 of the pendulum is of the same thickness as the arms 2 of the stick 1 and is thus merged with the arms 2 of the stick, the arms 2 and the stick 10 then forming a planar element.

Advantageously, the housing 3 is delimited by a rigid part of the arm 2, and by an elastic part 20 secured to a rigid part of the arm 2, the elastic part 20 being permanently biased towards the rigid part of the arm 2 delimiting the housing 3 .

Advantageously, the arm 2 has, in the extension of the housing 3, a recess 21 intended to facilitate the deformation of the elastic part 20.

According to a preferred embodiment, the housing 3 is substantially of the same shape as the counterweight 5. This embodiment is particularly advantageous since it allows the thickness of the balance 1 to be limited once the weights 5 are mounted on the balance 1.

In this preferred embodiment, the elastic part 20 extends in the median plane Pm of the web, the arm 2 having a recess 21 facilitating the deformation of the elastic part 20.

The pendulum 1 also comprises weights 5 for adjustment in the form of a cylinder, the weights 5 being provided with an opening 50 in the shape of a half-moon, or any other shape, and drive means 51 such as a notch adjustment or any other means known to those skilled in the art for adjusting the position of the counterweight 5.

According to a first embodiment, illustrated in figures 1 and 3 , the housing 3 and the elastic part 20 of shape complementary to the counterweight 5 comprise stops 30 near the upper and lower edges of the housing 3 respectively at the upper plane Ps and the lower plane Pi to hold the counterweight 5 in place according to the median plane Pm in the housing 3 while leaving it free to rotate.

Such housings 3 make it possible to have weights 5 fully embedded in the arms 2 of the pendulum 1. When the weights 5 are placed in the housings 3, the weights are pinched in the housings 3 and are thus held by friction in their position under the effect of the elasticity of the elastic arm 20.

According to a second embodiment, visible to figures 2 and 4 , the counterweight 5 comprises upper and lower wings intended to bear on either side of the arm 2, and more precisely on either side of the housing 3, respectively at the lower plane Pi and the upper plane Ps so as to maintain the counterweight 5 in the housing 3 while leaving it free to rotate in the said housing 3.

Advantageously, the counterweight 5 is integrated in the arm 2 of the pendulum 1 so that the front and rear faces are substantially in the upper plane Ps and the lower plane Pi. By substantially, it is meant that the front faces 52 and rear 53 are set back from 0 μm to 1 mm relative to the upper plane Ps and to the lower plane Pi in the first embodiment and that the upper and lower wings of the counterweight 5 are projecting up to 0.6 mm relative to the upper plane Ps and in the lower plane Pi in the second embodiment. Such an arrangement makes it possible to obtain a balance wheel with inertia adjustment having a reduced bulk.

Such a pendulum 1 according to the invention makes it possible in particular to mount the weights 5 on the arms 2 of the pendulum 1 whatever the direction of mounting of the latter. Generally, a person skilled in the art will choose the direction of mounting of the weights 5 on the balance wheel 1 according to the ease of access to the weights 5 once the balance wheel 1 is mounted in a movement.

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

Thanks to these various aspects of the invention, there is a compact balance making it possible to reduce the thickness of the timepiece movement and inexpensive to manufacture.

Of course, the present invention is not limited to the illustrated example and is susceptible to various variants and modifications which will appear to those skilled in the art, without departing from the scope of the invention as defined by the appended claims.

NOMENCLATURE

• 1. Balance wheel,
• 10. Serge,
• 11. Sailing,
• 12. Front face of the pendulum,
• 13. Rear face of the pendulum,
• 14. Drowning,
• 2. Arm,
• 20. Elastic part,
• 21. Obviously,
• 3. Housing,
• 30. Judgments,
• 4. Hub,
• 40. Orifice,
• 41. Pendulum axis
• 5. Weight,
• 50. Opening,
• 51. Means of training,
• 52. Front face of the counterweight,
• 53. Rear face of the counterweight,
• 54. Upper wing of the flyweight,
• 55. Lower wing of the flyweight,
• A. Pivot axis;
• Pm. Median plane;
• Pi. Lower plane;
• Ps. Upper shot.

Claims (13)

1. Balance (1) with inertia adjustment, for a timepiece, comprising a hub (4) defining the pivot axis (A) of said balance (1), a felloe (10), a web (11) extending between a lower plane (Pi) and an upper plane (Ps) on either side of a median plane (Pm), said web (11) comprising at least one arm (2) connecting said felloe (10) to said hub (4), said at least one arm (2) comprising a housing (3) configured to receive and maintain in place at least one inertia-block (5),
   said at least one inertia-block (5) having a front face (52) and a rear face (53) and characterised in that said at least one inertia-block is integrated into said arm (2) of said balance (1), and in that said at least one inertia-block (5) comprises upper leaves (54) and lower leaves (55) intended to bear on either side of said arm (2) respectively at the lower plane (Pi) and at the upper plane (Ps) in order to maintain said at least one inertia-block (5) axially in place.
2. Balance (1) with inertia adjustment for a timepiece, comprising a hub (4) defining the pivot axis (A) of said balance (1), a felloe (10), a web (11) extending between a lower plane (Pi) and an upper plane (Ps) on either side of a median plane (Pm), said web (11) comprising at least one arm (2) connecting said felloe (10) to said hub (4), said at least one arm (2) comprising a housing (3) configured to receive and maintain in place at least one inertia-block (5), said at least one inertia-block (5) having a front face (52) and a rear face (53), and having a cylindrical shape, said faces of which form the bases of the cylinder, characterised in that said at least one inertia-block is integrated into said arm (2) of said balance (1), in such a way that said front face and rear face are substantially in said upper plane (Ps) and said lower plane (Pi)
3. Balance (1) according to claim 2, wherein said front face (52) and said rear face (53) of said at least one inertia-block (5) are set back by 0µm to 1mm with respect to said upper plane (Ps) and to said lower plane (Pi).
4. Balance (1) according to claim 1, wherein said front face (52) and said rear face (53) of said at least one inertia-block (5) protrude up to 0.6mm with respect to said upper plane (Ps) and to the lower plane (Pi).
5. Balance (1) according to any one of claims 1 to 4, wherein said at least one inertia-block (5) is in place according to said median plane (Pm) of said web.
6. Balance (1) according to any one of claims 1 to 5, wherein said housing (3) and said at least one inertia-block (5) have a complementary shape.
7. Balance (1) according to any one of claims 1 to 6, wherein said at least one inertia-block (5) is pinched with a predetermined retention torque inside said housing (3).
8. Balance (1) according to any one of claims 1 to 7, wherein said arm (2) has an elastic portion (20) extending according to said median plane (Pm), said elastic portion (20) being capable of being deformed during the mounting of said at least one inertia-block (5).
9. Balance (1) according to any one of claims 2 to 8, wherein said housing (3) comprises stops (30) at the upper plane (Ps) and at the lower plane (Pi) in order to maintain said at least one inertia-block (5) axially in place.
10. Balance (1) according to any one of claims 1 to 9, wherein said at least one inertia-block (5) is set in said housing (3) of said arm (2) of said balance (1).
11. Balance (1) according to any one of claims 1 to 10, wherein said arm (2) and said felloe (10) have the same thickness.
12. Horological movement comprising a balance (1) according to one of claims 1 to 11.
13. Timepiece comprising a movement according to claim 12.

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