CH719238A2 - Balance with inertia adjustment. - Google Patents

Abstract

The invention relates to a balance wheel (1) for a clock movement, comprising rigid parts consisting of a hub (2) defining the pivot axis (A) of said balance wheel (1), a rim (3), four arm (4) connecting the rim (3) to the hub (2), and comprising four slots (7) for receiving and pinching in position a flyweight (6, 6'), each slot (7) being delimited by on the one hand by an arm (4), and on the other hand by an elastic arm (5) comprising a first end (5B) integral with said arm (4), and a second distal end (5A) free with respect to said hub ( 2), to said arm (4), and relative to the serge. According to the invention, the balance (1) comprises two pairs of weights (6, 6'), each pair of weights having different masses to ensure different regulating powers, a first pair of weights (6) allowing coarse adjustment, and a second pair of weights (6') allowing fine adjustment.

Description

Technical field of the invention

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

[0002] The invention also relates to a timepiece movement comprising such a system as well as a timepiece equipped with such a movement.

Technology background

[0003] A balance wheel is known, the moment of inertia of which is adjustable by means of adjustment screws which are arranged at its periphery. This type of device is known in particular within mechanical oscillators whose base frequency of the oscillator is adjusted by the moment of inertia of the balance wheel. In general, such a pendulum comprises a rim, arms and a certain arrangement of screws or weights fixed to the rim or the arm of the pendulum which make it possible, by adjusting their positions, to modify the moment of inertia of the pendulum. These screws or weights are positioned using keys or screwdrivers which allow their position to be adjusted.

[0004] It is for example known from patent CH264669 a balance equipped with headless adjustment screws which are screwed from the outside of the balance rim and which are embedded in its thickness. This embodiment is intended to advantageously replace the rockers provided with screws whose heads are arranged either projecting on the periphery of the rim, or in a recess of the rim.

[0005] From patent EP1837719B1 is also known a balance rim comprising studs of material directed radially towards the inside of the balance, which are each traversed by a tapped hole in order to accommodate weights which are screwed from the inside of the balance. . In this configuration, gripping the weights is not easy, and the balance rim thus risks being marked during adjustment.

[0006] These balances with adjustment screws have yet another drawback, which is the difficulty of guaranteeing an established adjustment during the operation of the movement, one or more screws being able to be partially or totally unscrewed, which is detrimental to the proper functioning and the regularity of the pendulum.

Summary of the invention

[0007] The object of the invention is in particular to overcome the various drawbacks of these known techniques.

[0008] More specifically, an object of the invention is to provide a balance with inertia adjustment allowing easy and rapid adjustment.

[0009] The invention also aims, at least in one particular embodiment, to provide a pendulum with inertia adjustment which is simple to implement and inexpensive to produce.

[0010] These objectives, as well as others which will appear more clearly subsequently, are achieved according to the invention with the aid of a pendulum for a clockwork movement, comprising rigid parts constituted by a hub defining the pivot axis of said balance, a rim, four arms connecting said rim to the hub, and comprising four slots for receiving and clamping in position a flyweight, each slot being delimited on the one hand by an arm, and on the other hand by an elastic arm comprising a first end secured to said arm, and a second distal end free with respect to said hub, said arm, and said serge sector.

[0011] According to the invention, the balance comprises two pairs of flyweights, each pair of flyweights having different masses to ensure different regulating powers, a first pair of flyweights allowing coarse adjustment, and a second pair of flyweights allowing adjustment END.

[0012] In accordance with other advantageous variants of the invention: - each pair of flyweights has different dimensions, the flyweights of the first pair being larger than the flyweights of the second pair, or vice versa; – the weights of the first pair are heavier than the weights of the second pair, or vice versa; – the pairs of flyweights are made of a different material; – the weights of the first pair and the weights of the second pair are arranged on a separate radius of the balance wheel; – the weights of the first pair are arranged on a first radius close to the rim and the weights of the second pair are arranged on a second radius close to the hub of the balance wheel; – the arms, rim and hub form a one-piece element.

[0013] 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.

Brief description of figures

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 non-limiting example, and the appended figures , among which: - Figure 1 is a perspective view of a balance according to the invention according to a first embodiment.

Detailed description of the invention

[0016] The balance wheel 1 for a clock movement, provided with a device for adjusting its inertia making it possible to adjust the frequency of oscillation of said balance wheel, comprises rigid parts constituted by a hub 2 defining the pivot axis A of the rocker arm 1, a rim 3 of circular shape, four arms 4 connecting said rim 3 to hub 2, and comprising four slots 7 for receiving and clamping in position a flyweight 6,6'.

Each slot 7 is delimited on the one hand by an arm 4, and on the other hand by an elastic arm 5 comprising a first end 5B secured to said arm 4, and a second distal end 5A free with respect to said hub 2, to said arm 4, and to said serge sector 3.

As shown, the balance 1 comprises four arms, forming a hub 4 at their intersection, the hub 4 being provided with an orifice 40 intended to receive a balance shaft.

The slot 7 is delimited by a rigid part of the arm 4 and by an elastic arm 5 which is permanently biased towards the arm 4 when the flyweight is inserted into the slot 7.

[0020] According to the invention, the balance comprises two pairs of flyweights 6, 6', each pair of flyweights having different dimensions to ensure different regulating powers, a first pair of flyweights 6 allowing coarse adjustment, and a second pair 6' flyweight allowing fine adjustment.

[0021] The flyweights 6, 6' of each pair are arranged in slots 7 facing each other with respect to the pivot axis A of the balance, or even arranged according to an axial symmetry of axis A, for a balanced distribution of the masses on the balance 1.

[0022] In order to distinguish the flyweights 6, 6' and position them correctly, the flyweights 6 of the first pair are larger than the flyweights 6' of the second pair, or vice versa.

According to one embodiment of the invention, the weights 6 of the first pair and the weights 6 'of the second pair are arranged on a separate radius of the balance.

[0024] For example, the weights 6 of the first pair are arranged on a first radius close to the rim 3 and the weights 6' of the second pair are arranged on a second radius close to the hub 2 of the balance, the pair of flyweights 6' close to the hub 2 of the balance allowing fine adjustment.

Similarly, the weights 6 of the first pair are heavier than the weights 6 'of the second pair, or vice versa. For this, different materials can be used to make the flyweights 6,6'. For example, the weights 6 are made of gold or a gold alloy such as 18K 3N gold, and the weights 6' are made of titanium or a titanium alloy such as grade 5 titanium.

The weights 6,6 'include a head 61 in the form of a disc and optionally a foot 62 of cylindrical shape.

Advantageously, the slot 7 has a shape complementary to that of the head 61 or the foot 62 of the counterweight 6, 6'. This embodiment is particularly advantageous because it makes it possible to limit the thickness of the balance 1 once the flyweights 6,6' have been mounted on the balance 1.

[0028] During the installation of the weights 6.6 'in the slots 7, the weights 6.6' are pinched in the slots 7 and are held by friction in their position under the effect of the elasticity of the arm rubber band 5.

The adjusting weights 6.6' are provided with a slot 63 to adjust the angular position of the weight by means of a tool cooperating with the slot 63 to transmit a torque around the axis of rotation of the flyweight 6.6'. According to the embodiment illustrated in Figure 1, each flyweight 6,6' has a flat 64 on the disc forming the head 61.

[0030] Of course, those skilled in the art will be able to adapt the balance 1 and set up any other type of weight 6,6 'so as to be able to adjust the inertia of the balance 1.

[0031] Such a configuration therefore allows simple and rapid adjustment of the balance, the larger and/or heavier weights initially allowing coarse adjustment to be made, and the smaller and/or lighter weights allowing in a second step to fine-tune the setting.

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

[0033] Thanks to these various aspects of the invention, there is a compact rocker arm making it possible to adjust the position of the flyweights easily and inexpensively to manufacture.

Of course, the present invention is not limited to the example illustrated and is susceptible to various variants and modifications which will become apparent to those skilled in the art.

Claims (10)

1. Pendulum (1) for a clock movement, comprising rigid parts consisting of a hub (2) defining the pivot axis (A) of said balance (1), a rim (3), four arms (4) connecting said rim (3) to the hub (2), and comprising four slots (7) for receiving and clamping in position a flyweight (6,6'), each slot (7) being delimited on the one hand by an arm (4), and on the other hand by an elastic arm (5) comprising a first end (5B) secured to said arm (4), and a second distal end (5A) free with respect to said hub (2), to said arm (4), and relative to the serge (3), characterized in that the balance (1) comprises two pairs of weights (6,6'), each pair of weights (6,6') having different masses to ensure different regulating powers, a first pair of weights (6) allowing coarse adjustment, and a second pair of flyweights (6') allowing fine adjustment. 2. Balance (1) according to claim 1, characterized in that the weights (6,6 ') of each pair are arranged in the slots (7) vis-à-vis with respect to the pivot axis (A ) of the balance (1). 3. Balance (1) according to claim 1 or 2, characterized in that each pair of flyweights (6,6') has different dimensions, the flyweights (6) of the first pair being larger than the flyweights (6' ) of the second pair, or vice versa. 4. Balance (1) according to one of claims 1 to 3, characterized in that the weights (6) of the first pair are heavier than the weights (6 ') of the second pair, or vice versa. 5. Balance (1) according to one of claims 1 to 4, characterized in that the pairs of weights (6,6 ') are made of a different material. 6. Balance (1) according to one of claims 1 to 5, characterized in that the weights (6) of the first pair and the weights (6 ') of the second pair are arranged on a separate radius of the balance. 7. Balance (1) according to claim 6, characterized in that the weights (6) of the first pair are arranged on a first radius close to the rim (3) and the weights (6 ') of the second pair are arranged on a second spoke close to the hub (2) of the balance wheel. 8. Balance (1) according to any one of claims 1 to 7, wherein the arms (2), the rim (10) and the hub (4) form a single piece. 9. Clock movement comprising a balance (1) according to one of claims 1 to 8. 10. Timepiece comprising a movement according to claim 9.