EP0762243B1 - Timepiece with power-reserve indication - Google Patents

Description

The present invention relates to a device power reserve indication for a part electronic watchmaking.

More particularly, the invention relates to such a device for an electronic timepiece in which electrical energy is generated by a generator powered by a spring barrel.

We have known watches for a very long time mechanical with a device for indicating the power reserve generally operating differential and coupled to both the winding and the barrel which houses the watch spring, source of its walking energy. The organ indicator of such a device is then driven into a direction when reassembling the barrel and in the other during that the spring relaxes and advances the watch.

Such a device for indicating the reserve of step could be used in a timepiece of the electronic type comprising an energy generator electric coupled to the spring barrel and intended for supply a timepiece electronic circuit regulated by a quartz oscillator.

However, in such an application, due to the presence of electronic means, the classic mechanism indication of the reservation may appear complex and bulky, while the electronic circuit allows considerably simplify the indication of the reserve of market.

The object of the invention is to propose a solution simple and effective in this context to indicate so flawless and clearly the power reserve of an electronic timepiece that draws its energy electric of a generator driven by a spring of barrel, this generator also serving to regulate the walk from the room.

The invention therefore relates to a timepiece comprising a barrel, a spring housed in this barrel, mechanically coupled time display devices audit barrel, a generator of electrical energy also mechanically coupled to said barrel and intended to deliver an AC voltage, a connected rectifier to said generator to deliver a DC voltage to from said AC voltage, and a circuit regulator powered by said DC voltage and intended to control the speed of rotation of said generator to a set speed, said regulator circuit for this purpose comprising means for braking said generator when said regulator circuit finds that said generator rotates at a speed greater than said set speed. This timepiece is characterized in that said means for braking said generator are arranged so as to exert on this generating successive braking and in that it includes a power reserve indicator device arranged to perform a measurement relating to said successive braking and to provide an indication visual of the power reserve as a function of this measured.

• la figure 1 montre un schéma général simplifié d'une pièce d'horlogerie selon l'invention;
• la figure 2 est un diagramme des temps illustrant le fonctionnement de la pièce d'horlogerie selon l'invention;
• la figure 2 est un diagramme des temps illustrant le fonctionnement de la pièce d'horlogerie selon l'invention;
• les figures 3a à 3f montrent plusieurs variantes de dispositifs d'affichage pouvant être utilisés dans la pièce d'horlogerie selon l'invention.

Other characteristics and advantages of the invention will become apparent during the description which follows, given solely by way of example and made with reference to the appended drawings in which:

• Figure 1 shows a simplified general diagram of a timepiece according to the invention;
• Figure 2 is a timing diagram illustrating the operation of the timepiece according to the invention;
• Figure 2 is a timing diagram illustrating the operation of the timepiece according to the invention;
• Figures 3a to 3f show several variants of display devices that can be used in the timepiece according to the invention.

We will first refer to Figure 1 which represents a simplified general diagram of a part of watchmaking according to the invention. It should be noted that the part of this diagram concerning the regulator circuit intended to control the speed of rotation of the generator of this timepiece, will not described in detail here, the skilled person can without hardly build this slaving device while referring to the description of the Swiss patent application No 686 332 in the name of the Applicant patent application. However, to make it easier understanding of the present invention, it will be recalled briefly here the essential elements of the diagram and operation of this regulator circuit.

The timepiece equipped with a device for indicating the power reserve according to the invention has a mechanical energy source formed by a barrel 1 housing a spring 1a of the usual type in the horological technique, with manual or automatic winding.

Barrel 1 is mechanically coupled to rotor 2a an electric generator 2 via a gear train 3 symbolized by mixed lines.

Generator 2 includes a coil 2b at terminals B1 and B2 from which an alternating voltage is generated Ug, when the rotor 2a is rotated, this rotor bearing a permanent magnet generating a field magnetic symbolized by an arrow in Figure 1 and with which the coil 2b is coupled.

The terminals B1 and B2 of the coil 2b are connected to a rectifier 4 whose output terminals 4a and 4b provide a continuous voltage Ua derived from the voltage Ug alternative and intended to supply the various circuits of the timepiece.

Needles 5 or any other conventional means mechanical time display, are coupled to the train gear 3 to allow time display current and possibly date and day and other time indications.

The rotation speed of the hands 5 is maintained at a constant average value thanks to a circuit regulator 6 which controls this value at a speed of setpoint Vc.

As described in the aforementioned patent application, the regulator circuit components 6 are designed to adjust the speed of rotation of the rotor 2a, so that the 5 hands rotate at the required indication speed just an hour, when the rotor turns at the speed of setpoint Vc. This is four turns per second, per example.

The servo circuit 6 includes an oscillator 7 stabilized by a watchmaking type quartz and a divider of frequency 8 reducing the frequency of this oscillator to a value usable by a functional block 9 which controls the grid of a semiconductor component 10, by example an n type MOS transistor.

The latter is connected by its main circuit to terminals B1 and B2 of the coil 2b of the generator 2. By Therefore, this semiconductor component when it is made conductive, allows to short-circuit this coil and thus have a braking effect on the movement of generator rotation 2.

a) la vitesse moyenne de rotation du rotor 2a soit supérieure à la vitesse de consigne Vc, tant que le ressort de barillet 1a n'est pas presque complètement désarmé, à condition que la bobine 2b ne soit pas court-circuitée par le composant semi-conducteur 10, et que

b) cette vitesse moyenne de rotation soit inférieure à la vitesse de consigne Vc, si la bobine 2a est court-circuitée et ce même lorsque le ressort de barillet 1a est complètement remonté et que le couple moteur qu'il fournit, a une valeur maximale.

The constructive characteristics as well as the functionalities of the various elements which have just been described are designed in such a way that

a) the average speed of rotation of the rotor 2a is greater than the set speed Vc, as long as the barrel spring 1a is not almost completely disarmed, provided that the coil 2b is not short-circuited by the semi-component -conductor 10, and that

b) this average speed of rotation is less than the set speed Vc, if the coil 2a is short-circuited, even when the barrel spring 1a is completely wound up and the motor torque which it supplies, has a maximum value .

It should also be noted that within the framework of the present invention, the elements and functionalities briefly listed above could be achieved possibly other ways than that described in the aforementioned patent application, provided that the speed of generator rotation is regulated correctly as indicated above. This regulation must therefore be made as a function of the setpoint speed Vc required (determined by the correct indication of the time by the needles 5) through successive braking of generator 2 due to short-circuits repeated from coil 2b thereof.

The brake control signal SF which circulates on a line 11 between the functional block 9 and the grid of the semiconductor component 10 is of logic type and in the example shown, we admit that this signal is in the state logic "0" as long as the timepiece delays, that is to say as long as the average speed of the rotor 2a is lower than the set speed Vc. In these conditions, the component or transistor 10 remains blocked and the rotor 2a is not braked.

On the other hand, as long as the timepiece advances or that the average speed of the rotor 2a is greater than the set speed Vc, the brake control signal SF is made up of pulses of determined duration starting at the start of each alternation, for example positive, of the Ug voltage at terminals B1 and B2 of coil 2b. during each of these pulses of the control signal SF, this one is in state "1" making the transistor 10 conductive and braking the rotor 2a.

Information concerning the alternating voltage Ug delivered on terminals B1 and B2 of coil 2b reaches to the functional block 9 via a line 12.

The invention is based on the observation that the braking signal SF circulating on the conductor 11, in other words the frequency with which the rotor 2a is braked, is a measure of the arming state of the spring 1. Indeed, when the barrel spring is completely raised, i.e. the reserve of is maximum, the engine torque it produces is maximum. In these conditions, the rotor will have permanently tendency to spin faster than speed Vc setpoint and must therefore be braked at each start of a period of Ug tension.

As the barrel spring 1a is relaxes, the engine torque it provides decreases gradually, so that the rotor must be less and less less frequently be braked and gradually speed is going to be less and less frequently higher than the set speed Vc, until it is no longer at all braked. This will then mark the exhaustion of the power reserve and the timepiece ends up stop if the user does not wind the spring 1a.

According to the invention, the device for indicating the power reserve thus includes means which account for successive braking over periods successive times of predetermined duration and which develop a display signal from the number of brakes occurring during these periods of time successive. An example of realization of these means will be now described in more detail.

The connection 11 of the functional block 9 which transmits the brake control signal SF at transistor 10 is connected to a counter 13 responsible for counting the number of this signal. Its counting input C is therefore connected to connection 11. Its reset input R is connected to the output Q of a frequency divider 14 which fixes successive time periods of duration predetermined. In this case, the entry of this divider 14 is connected to the output of the frequency divider 8 of to further divide the output frequency of the last.

A memory 15 formed for example by a circuit of classic rocker lock, is connected by its inputs E1 to E4 respectively to certain outputs, here the outputs Q9 to Q12, of the counter 13. The clock input C of this memory is connected to the output Q of the divider of frequency 14. The outputs Q1 to Q4 of memory 15 are respectively connected to the inputs E1 to E4 of a decoder 16 whose outputs, here S1 to S9, are connected respectively in turn at inputs E1 to E9 of the means display or display 17.

In the example considered which is by no means limiting, the output signal of the frequency divider 8 at a period of 250 ms. The divisor division rate of frequency 14 is 2048, which gives rise to its one pulse output every 512 seconds (see figure 2). This signal thus determines the period of time predetermined during which we count the times that the transistor 10 puts the coil 2b in short circuit.

Suppose that the rotor 2a rotates too fast by relative to the set speed Vc during the duration whole of the counting period and is braked at the start of each period of Ug tension (this means that the spring is only at the beginning of its relaxation), the number of pulses of the control signal SF is greater than 2048. Therefore, the counter 13 must have a capacity upper and have one more toggle which gives a minimum necessary capacity of 4096.

Figure 2 illustrates with a diagram representing some significant signals as a function of time, how does the device for indicating the power reserve that we have just described.

Curve a) shows the divider output signal of frequency 14. This signal has a duration period D, chosen here as being equal to 512 seconds.

Curve b) shows the SF signal applied to the input of counting the counter 13, it being understood that the figure shows, by way of illustration, two counting periods relatively spaced during which the numbers of pulses are quite different from each other. They therefore account for two operating phases during which the winding of the spring is strong, respectively weak.

Curve c) represents the content of counter 13 respectively during the two periods represented, while curve d) shows the output of memory 15 which each time keeps the information of the period of previous count and which is reset to zero each counting period expires thanks to a signal reset which passes over a conductor 18 (figure 1).

Figure 3 shows some examples of implementation practical display means 17. The figure represents in a), b), c) and d) displays indicating the value memory output 15 respectively by an indication not graduated (a)) or graduated in 12 hour intervals for example (b), c), and d)). Well heard, the ways to achieve these display means are multiple and the skilled person will know how to design them easily. For example, dial C of the coin watchmaking may include a G window behind which moves a colored strip which is animated by a small actuator (not shown) receiving its signal decoder 16 control. Alternatively, a series of light-emitting diodes.

In e) and f) of Figure 3, there is shown respectively two other variants, one comprising a liquid crystal display CL showing the reserve of walking in hours, and the other comprising several O openings forming a scale graduated in periods of 12 hours for example. A light emitting diode can be provided behind each of these openings being suitably controlled by the outputs of the decoder 16.

The resolution of the display 17 can be arbitrary, for example by periods of a determined number of hours, as shown in b), c), d) and f) of Figure 3, by units of hours as in e), or by all or nothing using a single indicator, a variant which has not been shown in the drawings. The skilled person will know adapt memory 15, decoder 16 and display 17 to these different display possibilities that fit all within the framework of the invention.

In particular, it is clear that an increase in resolution goes hand in hand with an increase in capacity from memory 15.

However, as already explained above, it is possible to realize the elements and functionality in a way other than that described in the aforementioned Swiss patent application No 686 332. So, we understands that by analogy it is also possible, while remaining within the scope of the present invention, to measure the duration between each occurrence of a pulse of SC braking to determine the power reserve instead to count this number of pulses for a fixed duration predetermined, as explained above. In in this case, the power reserve is large if the duration between two successive pulses is short, i.e. when you have to brake often, and the reserve is low if this duration is long.

It is also possible that memory 15 cannot memorizes that a certain number of most significant bits of the output information of the counter 13, for example the four most significant bits, as shown in the figure 1. Under these conditions, we can theoretically display 16 separate information on display 17. This is generally considered redundant for the envisaged goal, a maximum of nine pieces of information should be sufficient to provide adequate information the user of the timepiece on his reserve of market.

It should be noted in passing that the device according to the invention can, to some extent, inform the user on the mechanical state of the part of watchmaking. For example, if display 17 fails not at the maximum reserve graduation, whereas the user has just completely wound the spring, this will mean for example that the timepiece has need overhaul and requires re-lubrication.

Claims (9)

1. Timepiece comprising a barrel (1), a spring (1a) contained in this barrel (1), time display organs (5) mechanically coupled to said barrel (1), an electric energy generator (2) also mechanically coupled to said barrel (1) and intended to provide an alternating voltage (Ug), a rectifier (4) connected to said generator (2) for providing a continuous voltage (Ua) from said alternating voltage (Ug), and a regulating circuit (6) fed by said continuous voltage (Ua) and intended to regulate the rotational speed of said generator to a reference speed (Vc), said regulating circuit (6) comprising means for braking said generator (2) when said regulating circuit observes that said generator rotates at a speed larger than said reference speed, this timepiece being characterized in that said means for braking said generator is adapted to apply successive braking operations on this generator and in that it comprises a device for indicating the power reserve adapted for effecting a measure representative of said successive braking operations and for providing a visual indication of the power reserve as a function of this measure.
2. Timepiece according to claim 1, characterized in that said generator comprises a coil (2b) and in that said means for braking this generator comprises a switching organ (10) formed of a semiconductor component and connected by way of its principal circuit to the terminals of said coil (2b) in such a way that it may short-circuit said coil under the control of said regulating circuit (6).
3. Timepiece according to claim 1 or 2, characterized in that said measure representative of said successive braking operations is a measure representative of the frequency of these successive braking operations.
4. Timepiece according to any of the preceding claims, characterized in that said measure representative of said successive braking operations consists in determining the mean frequency of these successive braking operations during successive periods of time of determined duration (D), said device for indicating the power reserve comprising to this effect means (8, 14) for fixing these successive periods of time and means (13) for counting, during each of said periods, the number of times that said generator is braked.
5. Timepiece according to claim 4, in which said regulating circuit (6) comprises a horological quartz oscillator (7) and a first frequency divider (8), characterized in that said means for fixing said periods of time of determined duration comprises a supplemental frequency divider (14) connected to the output of said first divider (8).
6. Timepiece according to claim 4 or 5 depending from claim 2, characterized in that said means for counting comprises a counter (13) connected to the control grid of said semiconductor component (10) for counting the number of times that this component short-circuits said coil (2b) during said determined duration (D).
7. Timepiece according to claim 6, characterized in that said counter (13) is connected to a memory circuit (15) which memorizes the state of said counter during each of said successive periods of time.
8. Timepiece according to any of claims 1 to 3, characterized in that said measure representative of said successive braking operations consists in determining the duration of time between these successive braking operations, said device for indicating the power reserve comprising to this effect means (8, 14) for measuring the duration between two successive braking operations.
9. Timepiece according to any of the preceding claims, characterized in that display means (17) are arranged for providing an hour-graduated information or a multiple hour-graduated information on a dial (C) of said timepiece.

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