EP1426837B1 - Timepiece with power-reserve indication - Google Patents

Abstract

Timepiece has a barrel (1), spring (1a) within the barrel and time display means (5). An electric generator (2) is coupled to the barrel. The generator commands the activation means (10) of an analogue power reserve indicator (11), via an electric value transmitted by electric coupling between the generator actuating means, during braking periods.

Description

The present invention relates to a timepiece with a generator with indication of the power reserve.

Such a timepiece comprises a barrel, in which is housed a spring. Time display members are mechanically coupled to the barrel, as well as a generator of electrical energy. A regulator circuit is provided to slave the frequency of the generator to a reference frequency. For this purpose, the regulator circuit comprises switching means arranged to electrically brake the generator during braking periods, when the regulator circuit finds that the frequency of the generator is greater than that of reference.

It is known from the prior art, in particular the document EP 0 762 243 in the name of the present Applicant, such a timepiece, represented in the Figure 1 . The timepiece comprises a source of mechanical energy formed by a cylinder 1 in which is housed a spring 1a, manual or automatic winding, the winding device is not shown here.

The barrel 1 is mechanically coupled to the magnetized rotor 2a of an electric generator 2 via gear 3. The generator 2 comprises at least one coil 2b from which is generated an alternating voltage Ug, when the magnetized rotor 2a is driven by rotation, generating a magnetic field symbolized by means of an arrow and with which is coupled said at least one coil 2b.

The terminals of the coil 2b (or coils) are connected to a rectifier 4 outputting a rectified voltage Ua for supplying the regulator circuit 6, which will be discussed below.

Analogical elements for displaying a time indication 5, typically a set of hands or any other conventional means of mechanical time display, are mechanically coupled to the barrel through the gear trains 3 of the movement and are integral in rotation of the rotor 2a. The rotation speed of the needles 5 is maintained at a constant mean value by means of the regulator circuit 6, which is intended to slave the frequency of the generator to a reference frequency, so that the speed of the hands corresponds to the speed required to obtain a correct indication of the time.

This regulator circuit 6 will not be described in detail here, the person skilled in the art being able to construct such a servo-control device with reference to the description of Swiss Patent Application No. 686,332 in the name of the present Applicant. However, to make easier its understanding, we will recall here the essential elements of this circuit and its operation.

This regulator circuit 6 comprises a clock oscillator 6a stabilized by a quartz watchmaker and a frequency divider 6b reducing the frequency of this oscillator 6a to a frequency usable by a logic circuit 6c which controls, by means of a control signal 8, a switching member 7, for example a transistor, for braking the generator 2 in order to regulate its frequency at a reference frequency advantageously corresponding to a correct indication of the time by the display members of the time indication 5.

The timepiece according to this document also comprises a device indicating the power reserve 9. This device comprises a counter 9a counting the successive braking signals 8 for a period of time determined by means of an additional frequency divider 9b . A memory 9c is connected at the output of the counter 9b so as to store the data recorded during the determined period of time, at the output of which is connected a decoder 9d transforming the stored data into a control signal of incremental display means 9e of the power reserve 17, made by means of either a colored band or a liquid crystal cell. Incremental display means means a display 9e comprising successive lines that illuminate or appear to the point corresponding to the value of the measured or calculated quantity.

One of the main advantages of a timepiece with a generator is to be able to reconcile the use of a traditional mechanical watch movement with the precision of quartz.

This is why the solution recommended in the document EP 0 762 243 , although operating properly, nevertheless has the disadvantage of using incremental display members of the power reserve controlled by an indicator device consisting essentially of additional electronic elements to those necessary for the operation of the regulator circuit. In addition these additional electronic elements have the effect of increasing the overall consumption of the electronic circuit, which can be detrimental to the accuracy of the time indication.

Moreover, a solution that would incorporate a conventional device for indicating the power reserve has the disadvantage of not using the indications provided during the operation of the generator and in particular during braking periods of the latter.

In order to overcome the disadvantages of the prior art, the idea according to the invention is to provide an analog indication of the power reserve while using the indications related to the operation of the generator without increasing the power consumption of the room. watchmaking.

For this purpose, the invention relates to a timepiece as defined in the preamble of the description, characterized in that the generator is arranged to control means for actuating an analog component of the power reserve, by means of an electrical quantity transmitted by electrical coupling between the actuating means and the generator, during the braking periods.

According to an advantageous embodiment, the actuating means comprise a stator and a rotor, and are electrically coupled to the generator by means of the stator, the latter being also magnetically coupled to the rotor which mechanically displaces the analogical member display of the power reserve between a first position corresponding to the spring loaded at a second position corresponding to the disarmed spring.

• La Figure 1, déjà décrite, représente un schéma simplifié d'une pièce d'horlogerie selon l'art antérieur ;
• la Figure 2 représente un schéma général simplifié d'une pièce d'horlogerie selon un mode de réalisation préféré de l'invention ;
• les Figures 3A, 3B et 3C représentent la commande électrique selon le mode de réalisation préféré de la Figure 2 ;
• les Figures 4A et 4B représentent un mode de réalisation avantageux des moyens d'actionnement ;
• la Figure 5 représente une vue en coupe d'un dispositif indicateur selon un mode de réalisation avantageux de l'invention ;
• les Figures 6A, 6B et 6C représentent le déplacement du rotor aimanté utilisé dans les moyens d'actionnement en fonction de l'armage du ressort ; et
• la Figure 7 représente une variante des moyens de commutation selon le mode de réalisation de la Figure 2.

Other features and advantages of the invention will become apparent from the following description, given solely by way of example and with reference to the appended drawings in which:

• The Figure 1 , already described, represents a simplified diagram of a timepiece according to the prior art;
• the Figure 2 represents a simplified general diagram of a timepiece according to a preferred embodiment of the invention;
• the Figures 3A, 3B and 3C represent the electrical control according to the preferred embodiment of the Figure 2 ;
• the Figures 4A and 4B represent an advantageous embodiment of the actuating means;
• the Figure 5 is a sectional view of an indicating device according to an advantageous embodiment of the invention;
• the Figures 6A, 6B and 6C represent the displacement of the magnetized rotor used in the actuating means as a function of the arming of the spring; and
• the Figure 7 represents a variant of the switching means according to the embodiment of the Figure 2 .

We will now refer to the Figure 2 , which represents a simplified diagram of a timepiece according to a preferred embodiment of the invention. There are a number of elements in common with those presented in the context of the Figure 1 of the prior art, which will not be exposed again and whose references have been kept identical.

As mentioned in the above-described prior art, the generator 2 is braked during braking periods, when the regulator circuit 6 finds that the frequency of the generator is greater than a determined reference frequency. The voltage Ug across the coil 2b of the generator, shown in FIG. Figure 3A , is an AC voltage, where the braking periods of this coil are represented by the zones marked f1, f2 and f3.

It has been demonstrated that during these braking periods of the generator, energy is dissipated in the coil or coils 2b in the form of an electric magnitude G1, represented in FIG. Figure 3B , linked to the power reserve. Indeed, when the generator is braked frequently, the average energy dissipated is important, which means that the remaining power reserve is important. Conversely, when the generator is braked less frequently, the average dissipated energy decreases and the remaining power reserve is less important.

A device indicating the power reserve is therefore provided. It comprises actuating means 10 actuating an analog display element of the power reserve 11. These actuating means 10 are advantageously formed of an electrically actuated actuator having a stator comprising in particular a coil 10b and a magnetized rotor 10a.

The control of these actuating means 10 is transmitted by electrical coupling between the coils 2b and 10b, by means of the switching means 7a to 7d, in the form of an electrical quantity G2 dependent on the electrical magnitude G1 dissipated during braking periods. This electrical quantity G2, which advantageously corresponds to the electric current I passing through the additional coil 10b, makes it possible not only to supply the actuating means 10, but also to induce a mean magnetic field, rotating the magnetized rotor 10a.

In the particular example of the actuator with magnetized rotor, it is necessary to ensure that the average magnetic field induced in the additional coil 10b, is not zero. For this, different variants are possible for the implementation of the switching means, two variants of which are given by way of example, respectively to Figures 2 and 7 .

According to a first advantageous variant, represented in FIG. Figure 2 , it is intended to use as switching means an H-shaped rectifier bridge comprising 4 switches 7a to 7d.

In order to obtain a transmitted electrical magnitude G2, in the form shown in FIG. Figure 3C , the 4 switches 7a to 7d are controlled by a control signal 8 delivered by the regulator circuit 6, as explained below.

When no braking is to be applied to the generator coil 2b, the four switches 7a-7d are in the open position, as shown, and the electrical magnitude transmitted to the additional coil is zero.

When braking is applied to the coil 2b, it will be distinguished, as mentioned above, the positive and negative half-waves of the electrical magnitude G1. During the positive alternations of the electrical variable G1, the switches 7a and 7b are simultaneously switched to the closed position, while at the same time the switches 7c and 7d are simultaneously switched to the open position. And, during negative alternations of this same magnitude G1, the switches 7a and 7b are then switched simultaneously in the open position, while at the same time the switches 7c and 7d are then switched to the closed position. Inverse commutations of the switches can also be envisaged. The opposite commands applied to the switching means 7a-7b and 7c-7d are obtained via the inverters 8a and 8b.

The resulting transmitted electrical magnitude G2 is represented in FIG. Figure 3C . It will be noted for this purpose that according to this first variant, the magnitude G2 is advantageously transmitted during braking periods of the generator, that is to say, all the time that these periods.

According to a second possible variant, it is simply planned to transmit to the additional coil 10b either the positive half-waves or the negative half-waves, by using switching means comprising two switches, as shown in FIG. Figure 7 .

When no braking is to be applied to the generator coil 2b, the two switches are then switched to the open position.

When braking is applied to the coil 2b, one will also distinguish the positive and negative half-waves of the electrical variable G1. During positive half cycles, one of the switches is switched to the closed position, the other then switched to the open position. During the negative alternations, the inverse commutations are then carried out. According to this variant, the transmitted magnitude G2 provides information on the power reserve only during the positive or negative half-waves following the connection adopted, during the braking periods.

It will be noted for this purpose that according to this second variant, the magnitude G2, not shown, is transmitted during the braking periods, that is to say not necessarily all the time that these periods last, but for example only during certain periods. periods like positive alternations.

Whatever the variant used for the switching means, the magnetized rotor 10a is arranged to drive the display member 11 from a first position corresponding to the spring loaded to a second position corresponding to the disarmed spring. The detailed operation of this power reserve indicator device is given below in the context of the Figures 4 to 6 .

The Figure 4A represents a top view of a power actuator according to a preferred embodiment of the invention.

As mentioned above, the actuating means comprise in particular an actuator 10 comprising a coil 10b secured to a stator 12 having a cavity 13, preferably circular, thus defining first and second stator portions 12a and 12b, connected by narrowed areas of material 12c and 12d, said stator portions 12a and 12b defining two opposite magnetic poles (N and S) during the supply of the coil, that is to say during braking periods of the generator. It will be noted for this purpose that the stator is advantageously formed by a material with high magnetic permeability.

The circular cavity 13 has on its periphery two isthmals 14a and 14b substantially diametrically opposed. The axis D defined along the diameter connecting the two isthms 14a and 14b forms for example an angle of approximately 45 ° with the axis E defined along the length of the stator 12.

The actuator 10 also comprises a magnetized rotor 10a, preferably circular, centered in the cavity 13 defined by the stator 12 and rotatably mounted on a shaft 15. The magnetic poles (N and S) of the magnetized rotor 10a have been represented according to the so-called rest position of the rotor.

The position of rest is understood to mean Figure 6C ), the position taken by the rotor 10a when the stator coil 10b is not energized, ie when the average induced magnetic field in the coil is zero. This rest position is defined in particular by the geometry of the stator 12 and the position of the isthmus 14a and 14b. The rotary displacement of the magnetized rotor 10a with respect to the stator 12 is given in detail in FIGS. Figures 6A to 6C .

The Figure 4B represents the drive mechanism preferably used with the actuator 10 of the Figure 4A . The rotor, not visible on this Figure 4B , is mounted on the shaft 15, the latter defining with the drive gear 16, a drive mobile of the indicator member of the power reserve. As will be shown in the context of Figures 6A to 6C , the useful angle of indication of the power reserve being of the order of 60 °, it is advantageously provided with a reduction mobile formed by a reduction gear 17 engaged with the drive wheel 16 and mounted on a shaft 18 driving the analog body indication of the power reserve represented by Figure 5 . It is advantageously provided a ratio of 2 or 3 between the number of teeth of the drive wheel 16 and that of the gear wheel 17, which increases the angle to view the power reserve for a useful angle of 60 °, a viewing angle of about 120 ° or 180 ° is available respectively.

In order to prevent the power reserve indicator member from being displaced outside the viewing angle, for example due to shock, or excessive manipulation of the winding mechanism, means are provided for blocking this indicator organ. For this purpose, it is preferable to use a reduction wheel 17 having a recessed sector 20, defining first and second bearing surfaces 21a and 21b intended to cooperate with a single abutment 19. Advantageously, the recessed sector 20 has an angle at center of 120 °. The two extreme positions for which the bearing surfaces 21a and 21b are in contact with the stop 19 correspond to the two extreme positions of the power reserve indicator member, that is to say to a first corresponding position. the spring loaded and a second position corresponding to the disarmed spring.

It should be noted that other stop devices can be provided, in particular in the form of pins placed on either side of the viewing angle on the dial of the timepiece.

The Figure 5 represents a sectional view of the entire power reserve indicator device according to the embodiment shown in FIGS. Figures 4A and 4B . The plate 22 serves as a support, in particular for the stator 12 and the coil 10b, as well as for the shafts 15 and 18 on which the driving gears 16 and gear 17 respectively are respectively mounted. An upper bridge 23 makes it possible to fix the stop 19 A recess made in the upper bridge and in the dial 24 of the timepiece allows the passage to the shaft 18 on which is mounted an analog body 11 indicating the power reserve, typically a needle moving in look of adequate graduations. Of course, the use of a disk providing an indication through a window can also be provided, or any other suitable analog display means.

The Figures 6A, 6B and 6C represent the displacement of the magnetized rotor relative to the stator according to the winding of the spring housed in the timepiece cylinder. This displacement corresponds to the evolution of the magnetic equilibrium position defined by the opposition between the average magnetic coupling existing between the stator (12) and the rotor due to the electrical quantity transmitted during the braking periods and the positioning coupling existing between the stator and the rotor due to the geometry of the stator, the latter being at high magnetic permeability.

The Figure 6A corresponds to the initial position of the magnetized rotor 10a when the spring is fully armed. The generator is then frequently braked by the switching means to reduce its frequency of operation at the reference frequency. During the braking periods, the coil 10b is electrically coupled to the coil 2b of the generator, which generates a magnetic field through the stator 12. The resulting average induced magnetic field makes it possible to assimilate the stator to a magnetic dipole, whose a first stator part 12a corresponds for example to the north magnetic pole N, and a second stator part 12b to the south magnetic pole S.

In this case, the pole N of the stator part 12a attracts the pole S of the magnetized rotor 10a. At this magnetic torque between the stator and the rotor is opposed the positioning torque whose effect is to attract the magnetized rotor 10a to its rest position shown in FIG. Figure 6C . The position of the rotor is given by the magnetic equilibrium position.

The Figure 6B represents an intermediate position for which the spring is no longer fully armed. The braking applied to the generator is then less frequent and the magnetic dipole means of the stator is less important. Thus, the magnetic equilibrium position of the magnetized rotor 10a is between the initial position defined at Figure 6A and the rest position defined at the Figure 6C . The rotor rotates in the direction indicated by the arrow.

The Figure 6C represents as mentioned above, the rest position of the magnetized rotor 10a, that is to say the position for which the generator is no longer braked, when the spring is disarmed or when the generator is not more able to operate at the reference frequency.

In this case, the magnetic torque between the stator and the rotor is zero and therefore the magnetic equilibrium position of the rotor no longer depends only on the positioning torque, the rotor then being in its so-called rest position depending on the geometry of the stator . For this purpose, the stator has narrowed areas of material 12c and 12d and isthmals 14a and 14b formed at the periphery of the circular cavity 13. The rest position then forms an angle (a) of about 80 ° between the E axis of the stator and the north-south axis (NS) of the magnet rotor.

It will be noted on this occasion, that there are actually two rest positions, the one represented and the position of inverse polarity, that is to say angularly shifted by 180 °. The magnet is arbitrarily placed in the position shown when mounting this indicator device of the power reserve.

As additional remarks, it will be noted that it has been demonstrated that the analog power reserve indication member gives information on the aging of the oil used for the movement of the timepiece, especially at the level of the wheels, this body not indicating a maximum reserve when the spring is completely armed. Advantageously, this member will also be used as an indicator of aging of the timepiece oil for replacement.

It should also be noted that a viscous oil is advantageously used at the indicator device in order to increase its stability.

In addition, it should be noted that the planned generator preferably corresponds to that defined in Figure 1 of the document EP 1 109 083 filed in the name of the present Applicant, incorporated herein by reference. Such a generator comprises a rotor having two flanges arranged on either side of three flat coils, connected in series, forming the stator and shifted substantially 120 ° relative to one another relative to the axis of the rotor. in the same plane orthogonal to this one. Six magnets are fixed radially and at regular intervals on each flange, vis-à-vis the coils. The polarity of two consecutive magnets or vis-à-vis is opposite.

It will be noted for this purpose that it is possible to provide other modes of execution of the generator, in particular a generatrix mechanically coupled to the mainspring of the cylinder so as to generate an oscillation movement at a frequency controlled by means of the circuit regulator.

Finally, it will be noted that other embodiments of the actuating means may be provided, in particular according to the two variants presented below.

According to a first variant, the actuating means comprise in particular a connected coil, by means of switching means, for example from the Figure 2 with the generator coil or coils during braking periods, in which a ferromagnetic body, such as an iron-nickel alloy or a combination of alloys of the steel-brass type, is disposed. During braking periods, the coil is fed via an electrical quantity transmitted by the generator, dependent on the power reserve. The induced magnetic field, depending on this electrical quantity and therefore on the power reserve, has the effect of deforming the ferromagnetic body by magnetostriction. This deformation of the ferromagnetic body is used to indicate the power reserve by any appropriate mechanical means.

According to a second variant, the actuating means comprise in particular a wire formed by a shape memory alloy connected in series with the generator coil or coils during braking periods of the latter. A shape memory alloy can acquire two different shapes, a high temperature form and a low temperature form, these two forms being imposed by the electrical quantity transmitted during the braking periods which has the effect of increasing the temperature of said wire formed by an alloy of this type. The most commonly used alloys are CuZnAl, TiNi and CuAlNi. It should be noted that, advantageously, the addition of Beryllium in CuAl alloys makes it possible to obtain significantly lower processing temperatures, while ensuring good stability at high temperature.

Claims (9)

1. Timepiece including a barrel (1), a spring (1a) housed in the barrel, time display members (5) mechanically coupled to said barrel, an electric energy generator (2) also coupled to said barrel, and a regulator circuit (6) for enslaving the frequency of said generator to a reference frequency, said regulator circuit including for this purpose switching means (7) arranged for electrically braking said generator during braking periods, when said regulator circuit detects that the frequency of said generator is higher than the reference frequency, said timepiece being characterized in that the generator is arranged so as to control actuating means (10) of an analogue power reserve member (11), via an electric quantity (G2) transmitted by electric coupling between the actuating means and the generator, during said braking periods.
2. Timepiece according to claim 1, characterized in that said actuating means (10) of said power reserve display member are arranged so as to move said display member (11) from a first position corresponding to the spring being wound to a second position corresponding to the spring being let down.
3. Timepiece according to claim 1 or 2, wherein the generator includes at least one coil (2b) and characterized in that said actuating means include an additional coil (10b), said electric coupling between the actuating means and the generator being achieved by said switching means (7a, 7b, 7c, 7d) arranged for electrically coupling said coils at the time of said braking periods.
4. Timepiece according to claim 3, characterized in that said electric quantity (G1) is alternating, and in that said switching means (7a, 7b, 7c, 7d) are arranged so as to switch so as to transmit a rectified electric quantity (G2) to said additional coil (10b).
5. Timepiece according to claim 3 or 4, characterized in that the actuating means (10) include an electrically controlled actuator formed by a stator (12) including said additional coil (10b) and by a magnetised rotor (10a), the latter being magnetically coupled to the stator and mechanically coupled to said analogue power reserve display member (11).
6. Timepiece according to claim 5, characterized in that the stator (12) has a circular cavity (13) on which are arranged two necks (14a, 14b) arranged such that the useful angle of the rotor (10a) corresponding to its rotating movement is approximately 60°.
7. Timepiece according to claim 5 or 6, characterized in that said rotor (10a) is arranged so as to be coupled to said analogue power reserve display member (11) via a gear reduction wheel set including a gear reduction wheel (17) having a hollowed sector (20) and in that a stop member (19) is arranged in said sector so as to limit the rotational angle of said wheel.
8. Timepiece according to any of claims 1 to 7, characterized in that a viscous oil is arranged so as to be used to obtain a stable indication of the power reserve by the display member.
9. Timepiece according to any of the preceding claims, characterized in that the analogue power reserve display member also is arranged so to provide an indication as to the aging of oils of said timepiece, the first position being slightly offset.

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