EP0427077B1 - Electronic timepiece - Google Patents

Abstract

The invention relates to an electronic timepiece. This timepiece comprises: - a time base (G) supplying an output signal (Se), - means of displaying the time (TAF) connected to this time base by the intermediary of a dividing chain (14), - means of adjustment (16) connected to the dividing chain for adjusting over a predetermined periodicity the frequency variations of the output signal (Se), and - generating means (20) for generating an auxiliary signal (Sr) having a frequency distinctly higher than that of the output signal (Se). This timepiece is characterised in that the generating means (20) comprise slaving means to slave the frequency of the auxiliary signal (Sr) to that of the output signal (Se), the generating means being arranged to be connected selectively to the junction between the time base (G) and the dividing chain (14) in order to shorten, when checking the operation, the predetermined adjustment periodicity. The invention is particularly adapted so that its operation is efficiently measured.

Description

The invention relates to an electronic timepiece, the running of which can be controlled by a measurement system, such as those fitted to watch production lines or those currently available to watchmakers and jewelers.

Electronic timepieces, such as watches, are generally provided with a time base comprising a quartz resonator capable of supplying, in the most stable manner possible, a signal whose frequency is divided, the divided signal being transmitted, in the case of an analog electronic watch, to a stepping motor which controls time indicators (hands, calendar), while this signal is transmitted in the case of a digital watch to a circuit which generally controls a liquid crystal display device.

The precision of these timepieces is, on the commercial level, a characteristic which can be fundamental.

It was first considered that to obtain this precision it was necessary to be rigorous on the manufacture of quartz, so that for a long time one sought to set up methods and devices of implementation always more efficient, unfortunately excessively expensive .

To overcome this, we used electronic walking correction circuits incorporated in the watch circuit, which allowed us to use quartz whose frequency can deviate by a certain amount from the nominal frequency. . Therefore, we can admit a certain dispersion of the natural frequencies of quartz manufactured in series. In this case, for each time base, the frequency of its output signal is adjusted, either by adding pulses in the case of a low frequency crystal, or by suppressing pulses in the case of a high frequency quartz.

The pulse suppression technique or inhibition technique is that to which reference will be made in the description which follows. follow, it being understood that the invention can be applied by analogy to the technique of adding pulses.

In FIG. 1, there has been represented, in number N of pulses with respect to time t , the drift of an uncorrected output signal Se supplied by the time base, with respect to a nominal signal Sn which would cause the timepiece in a strictly exact manner.

In Figure 2, there is shown, still with respect to the nominal signal Sn, the shape of a corrected signal Sinh which corresponds to the output signal Se, but adjusted by inhibition.

The inhibition therefore consists in removing from the time base signal a number K of pulses every T seconds, T being the inhibition period.

To be able to carry out the finest possible inhibition (resolution), a relatively large inhibition period T is chosen, generally between 480 and 640 seconds, or between 8 and a little more than 10 minutes.

However, this inhibition period constitutes a major obstacle to the effective control of timepieces, control which is carried out for the following reasons.

First, like any industrial or semi-industrial product, and for obvious reasons of quality, timepieces are checked at the manufacturing stage.

This control which is carried out by a measurement called gait measurement must, to minimize the costs, be carried out over the shortest possible period M, the duration of which generally does not exceed one minute, that is to say a much shorter time than the above inhibition period.

Second, we know that in use, because of its aging or external constraints to which it is sensitive, such as humidity or temperature, quartz provides a signal which varies over time.

Thus, watchmakers have at their disposal a measuring device which, by an acoustic reception process or by magnetic detection, monitors the progress of timepieces that their customers entrust to them for this purpose.

As shown in FIG. 3, the timepiece 1 which must be checked is placed on a device 2 which indicates by a display means 3 if the running of the watch is good or if, on the contrary, it has any deviation.

Here again, this type of device available to watchmakers is designed to operate, for each measurement, over a period M of the order of a minute.

We observe, in the two cases which have just been described, the phenomena represented respectively in FIGS. 2a and 2b, these phenomena occurring as a function of the instant when the measurement is launched.

The first measurement MS1 represented in FIG. 2a is launched at time T1 and is stopped at time T2.

The measurement period M being eight to ten times shorter than the inhibition period T (this scale not being observed in the drawings), it can be seen that the inhibition could not have taken place, so that despite l existence of a correction at the level of the signal supplied by the time base, there remains between the corrected signal Sinh and the nominal signal Sn an error Na, corresponding to a number of pulses transmitted in excess.

The opposite phenomenon occurs for the measurement MS2 represented in FIG. 2b, where it begins at time T3 and ends at time T4.

Here, the inhibition occurs during the measurement period M so that the signal Sinh is deficient in a number Nb of pulses.

In summary, when checking a classic timepiece provided with electronic inhibition, the measurement of the gait can turn out to be completely false since the period M over which the measurement is carried out is much shorter than the period inhibition T. Thus the display means are supplied, during this measurement, on the basis of an output signal, either too corrected or not enough, this since, as shown in FIG. 2a, the inhibition in one case could not be realized, or on the contrary in another case as shown in Figure 2b, just to realize it induces the transmission of an over-corrected signal.

We know from the Acts of the European Chronometry Congress of 23 and 24 September 1988 in Geneva, Session 3, Communication 14, a timepiece in which adjustment means are provided which, with a periodicity of 640 seconds, adjust the frequency of the control signal of the display means of this part (these display means being constituted inter alia by the motor) in order to compensate for the frequency differences of the time base which are caused in particular by temperature variations . This timepiece also includes means making it possible to reduce the periodicity of the adjustment, and this in view of ensuring a frequency control of the time base which is not of too long duration. These means include a ring oscillator which is capable of supplying a signal of a relatively high frequency (greater than 2.1 MHz) and which is connected to the motor control circuit by means of a counting circuit. - even connected to an arithmetic and logic circuit coupled to a temperature measurement circuit.

This arrangement makes it possible to replace, during a control, the pulses normally applied to the motor, by control pulses repeating with a reduced periodicity (of 10 seconds) compared to the periodicity of the running correction in normal operation.

For this purpose, the ring oscillator which has, by construction, an unstable frequency, is controlled by comparison with the frequency of the time base oscillator then the periodicity of the control pulses is adjusted, by the arithmetic circuit and logical, as a function of the deviation of the oscillation of the time base caused by temperature variations. The control pulses which then take into account the influence of the gait adjustment can then be detected by a measuring device installed for example at the retailer responsible for after-sales service.

It can be seen that this assembly must necessarily include a complex calculation circuit which risks introducing errors, precisely when it is desired to check the correct functioning of the timepiece. In addition to its high cost, this assembly therefore has the drawback of not ensuring reliable control of the running of the watch. Finally, during the check, this assembly necessarily prevents the exact time of the timepiece from being kept.

The object of the invention is to provide a timepiece comprising a simple and reliable circuit allowing easy control of the movement of a timepiece provided with an adjustment device by inhibition or by adding a pulse, while offering the possibility of keeping the exact time.

• une base de temps destinée à fournir un signal de sortie dont la fréquence est une référence temporelle,
• des moyens d'affichage de l'heure raccordés à cette base de temps par l'intermédiaire d'une chaîne de division qui est susceptible de transformer le signal de sortie fourni par la base de temps en un signal dont la fréquence divisée est adaptée auxdits moyens d'affichage,
• des moyens d'ajustement raccordés à ladite chaîne de division pour ajuster sur une périodicité prédéterminée les écarts entre la fréquence dudit signal de sortie et une fréquence nominale idéale, et
• des moyens générateurs destinés, en vue du contrôle de la marche de ladite pièce d'horlogerie, à engendrer un signal auxiliaire de fréquence nettement supérieure à la fréquence dudit signal de sortie, cette pièce d'horlogerie étant caractérisée en ce que lesdits moyens générateurs comprennent des moyens d'asservissement pour asservir la fréquence dudit signal auxiliaire à celle du signal de la base de temps, et en ce que ces moyens générateurs sont agencés pour être connectés sélectivement à la jonction entre ladite base de temps et ladite chaîne de division pour raccourcir, lors du contrôle de la marche, ladite période prédéterminée d'ajustement.

It therefore relates to a timepiece comprising:

• a time base intended to supply an output signal whose frequency is a time reference,
• time display means connected to this time base via a division chain which is capable of transforming the output signal supplied by the time base into a signal whose divided frequency is adapted to said times display means,
• adjustment means connected to said division chain for adjusting the deviations between the frequency of said output signal and an ideal nominal frequency over a predetermined periodicity, and
• generator means intended, with a view to controlling the running of said timepiece, to generate an auxiliary signal of frequency clearly greater than the frequency of said output signal, this timepiece being characterized in that said generator means comprise servo means for slaving the frequency of said auxiliary signal to that of the time base signal, and in that these generating means are arranged to be selectively connected to the junction between said time base and said division chain to shorten , during the gait control, said predetermined adjustment period.

Thanks to these characteristics, it is the division chain of the timepiece which receives, during the control, a signal whose frequency of high value is rigorously subject to the frequency of the time base. However, as the periodicity of the adjustment of the gait (that is to say for example the inhibition) is derived directly from this chain of division, one can dispense with using a complex circuit of calculation. It therefore follows that the control can be carried out by means of the implementation of a simple circuit supplement which does not significantly increase the cost of the timepiece.

We know, from patent CH-A-664,868, another timepiece comprising a device whose primary purpose is to programming of a non-volatile memory for the modification of the inhibition number K , this timepiece likewise comprising means for its control, said in rapid mode. These means make it possible to raise the frequency of the signal supplied to the motor at a frequency F (in particular up to a frequency of the order of 32 Hz) by increasing to a value F / 2 the speed at which it is effected by inhibition the adjustment of the division rate, while in normal operation of this part, this adjustment is made every 60 seconds.

Thus, it is possible, thanks to these means, to carry out extremely rapid running checks, that is to say over approximately four periods of 1.32 ^e of a second.

However, this timepiece cannot find its application to measurement by conventional devices.

Indeed, to control the running of this timepiece it is essential to be able to compare, over two successive periods, signals with a frequency of about 32 Hz, the first period corresponding to the running of the watch without inhibition while that the second corresponds to that with inhibition.

Therefore, the control device, by comparison between these signals, must be able to determine whether the number of inhibitions present has been properly programmed.

This control method therefore requires a very specific device and does not meet the purpose set here.

In addition, in this type of control, the exact time is lost, which is a major drawback for many customers.

• la figure 1 est un graphique représentant, en nombre d'impulsions N par rapport au temps t, l'allure d'un signal de sortie Se provenant d'une base de temps, par rapport à un signal nominal Sn ;
• la figure 2 est un graphique similaire à celui de la figure 1, mais dans lequel on a représenté l'allure d'un signal inhibé Sinh correspondant au signal Se mais corrigé, par rapport au même signal nominal Sn ;
• les figures 2a et 2b sont des graphiques représentant de façon plus détaillée le comportement d'un signal inhibé Sinh par rapport au signal nominal Sn, d'une part lors d'une mesure MS1, et d'autre part, lors d'une mesure MS2 ;
• la figure 3 est une vue schématique en perspective d'un appareil de contrôle sur lequel est posé une pièce d'horlogerie dont la marche est à vérifier ;
• la figure 4 est une représentation très schématique d'une pièce d'horlogerie selon l'invention, en mode d'utilisation normal ;
• la figure 5 est une représentation du schéma de la figure 4 mais commuté en mode de contrôle.

The invention will be better understood on reading the detailed description which follows, taken with reference to the appended drawings which are given solely by way of example, and in which:

• FIG. 1 is a graph representing, in number of pulses N with respect to time t , the shape of an output signal Se coming from a time base, with respect to a nominal signal Sn;
• FIG. 2 is a graph similar to that of FIG. 1, but in which the appearance of an inhibited signal Sinh corresponding to the signal Se but corrected, is shown relative to the same nominal signal Sn;
• FIGS. 2a and 2b are graphs representing in more detail the behavior of an inhibited signal Sinh with respect to the nominal signal Sn, on the one hand during a measurement MS1, and on the other hand, during a measurement MS2;
• Figure 3 is a schematic perspective view of a control device on which is placed a timepiece whose operation is to be checked;
• Figure 4 is a very schematic representation of a timepiece according to the invention, in normal use mode;
• Figure 5 is a representation of the diagram of Figure 4 but switched to control mode.

Referring now to Figure 4, there will be described below a first embodiment of an electronic timepiece according to the invention, shown in its normal mode of use.

This timepiece includes a time base G which is provided with an oscillator 10 controlled by a quartz resonator 12 and which is capable of supplying an output signal Se with a frequency of 32,768 Hz.

At the output of the time base G is connected a first division chain 14 which receives from this time base G the output signal Se.

The division chain 14 has a division rate D equal to 32,768 and it is linked to a TAF display means which is sensitive to a signal divided into frequency Sd, emitted by this division chain.

The TAF display means comprises for example, in the case of an analog electronic timepiece, a stepping motor coupled to a gear train driving the hands. Of course, it can be formed, in the case of a digital electronic timepiece, by a microprocessor associated with a display of the liquid crystal type.

The display means TAF processes and transforms into a time indication the signal Sd transmitted by the first division chain 14, the signal Sd having a frequency of 1 Hz.

The timepiece of Figure 4 further includes an adjustment system 16 of the output signal Se.

The adjustment system 16 acts by a correction process on the division chain 14. For the description of the invention, reference is made below to a correction process by inhibition, it being understood that the invention can be '' apply indifferently to the technique of adding pulses.

A detailed description will not be given here of the operation or of the structure of an inhibition adjustment system since this type of system is now conventional and well known.

Such a system is for example described in patent CH-A-664,868.

At the output of the first division chain 14 is connected a second division chain 18.

This second division chain 18 which belongs to the adjustment system 16 consists of two dividers 18a and 18b.

The first divider 18a which is connected to the input of the second 18b has a division rate with a value N for example equal to 48, while the second divider 18b has a division rate U for example equal to 10.

Thus, the adjustment system 16 conventionally operates, in normal use mode, over an inhibition period T of 480 seconds.

Furthermore, the timepiece according to the invention comprises generator means 20 which, when they operate in the control mode and as will be explained below, allow efficient and error-free verification of the progress of the timepiece. These generator means 20 comprise at least one phase comparator 22 and a variable frequency oscillator 24 which is preferably of the voltage controllable type.

To this end, it will be noted that the power supply terminal of the variable frequency oscillator 24 is connectable to the power supply V + of the timepiece by means of a switch 31 provided between said power supply and the terminal d supply of this oscillator 24. One of the inputs of the phase comparator 22 is connectable to the output of the time base G by means of a switch 30 which is arranged between the output of the time base G and the input of the phase comparator 22.

Since the other input of the phase comparator 22 is connected to the output of the variable frequency oscillator 24, the frequency of which is controlled by the comparator 22, this arrangement forms a means for controlling the generator means 20 at the time base. G.

Consequently, the generator means 20 are capable of supplying an auxiliary signal Sr (FIG. 5) whose frequency can be controlled by the frequency of the output signal Se of the time base G.

A switch 32 is provided at the junction 28 between the time base G and the frequency divider 14. The common terminal of this switch 32 which forms the output terminal is therefore connected to the input of the division chain 14, while one of its input terminals is connected to the output of the time base G and the other is connected to the output of the variable frequency oscillator 24.

The switches 30, 31 and the switch 32 form actuation means arranged so that they simultaneously allow the supply of the generator means 20 and the connection of these generator means 20, on the one hand at the outlet of the base of time G with a view to their enslavement, and on the other hand at the entry of the chain of division 14.

These actuating means are moreover arranged so that when one acts on a member of the timepiece which is externally accessible, such as for example the rod and the crown 4 (FIG. 3), these actuating means are in their active (switches 31, 30) or switched (switch 32) position.

The construction of such a control by the rod and of these actuation means 30, 31, 32 is not given here in detail since it is conventional skills of a manufacturer of timepieces.

Furthermore, a divider 26 is provided between the output of the variable frequency oscillator 24, after its junction with the switch 28, and the input of the frequency comparator 22.

This divider 26 having a division rate P, it is therefore understood that the signal Sr which will be supplied by the generator means 20, during the control, may have a frequency P times higher than that of the output signal Se supplied by the base of time G.

In addition, as shown in Figures 4 and 5, it is particularly advantageous to provide a second switch 36 associated with the TAF display means.

The common terminal 36a of this switch, which here forms an output terminal, is connected to the input of the display means TAF.

One of the other terminals 36b, 36c which form input terminals, namely terminal 36b, is connected to the input of the divider 18a. The other terminal 36c is connected to the output of the first divider 18a of the division chain 18, this chain managing the operating frequency of the adjustment system 16.

It is therefore understood that thanks to this switch 36 and to the junction of its terminals 36b and 36c, the display means TAF can be selectively connected, either to the input or to the output of the divider 18a.

In addition, it will be specified that advantageously the division rate P of the divider 26 is chosen equal to the division rate N of the divider 18a.

According to yet another embodiment, the timepiece according to the invention can be provided with a divider 40 with a division rate Q, connected between the output of the time base G and the common junction of the switch 30 and switch 32.

This divider 40 makes it possible to decrease by Q times the frequency of the signal Sr supplied by the generator means 20, the division rate of the division chain 14 being, therefore, equal to D / Q.

Furthermore, in this second embodiment, a signal is provided at the input of the phase comparator 22, the duty cycle of which is that of a square signal, which makes it possible to use a phase comparator of simplified construction.

The operation of the timepiece according to the invention is as follows.

When using the timepiece in normal operating mode, the rod by means of its crown 4 (FIG. 3) is in its pushed position or simply pulled up to its reset notch. time or date movement, so that the switches 31, 30 and the switches 32, 36 are left in the position shown in FIG. 4.

The generator means 20 are not supplied and the time base G delivers to the division chain 14 its output signal Se.

The display means TAF is connected directly to the output of the division chain 14 from which the signal Sd comes.

Consequently, the signal Sd having a frequency of 1 Hz, the motor advances by one step every second and, via the hands, provides the normal time indication.

In addition, the division rate of the division chain 18 being equal to N x U, ie 480, the inhibition by the adjustment system 16 is repeated over a periodicity of 480 seconds.

During the control of the timepiece, it is placed on the console of the control device 2, which is shown in FIG. 3, the rod thanks to the crown 4 having been pulled to its so-called position. gait control.

In this position of the rod, and as shown in FIG. 5, the switches 30 and 31 are in their active position, so that the generator means 20, and more particularly the variable frequency oscillator 24, are supplied.

The time base G being connected to the generator means 20, and more particularly to the phase comparator 22, the frequency of the generator means 20 is controlled by that of the time base G.

Furthermore, the switches 32 and 36 are in their switched position.

Thus, the input of the division chain 14 is no longer connected to the output of the time base G, but to that of the generator means 20.

The generating means 20 therefore supply the division chain 14 with the auxiliary signal Sr which is a signal P times faster than the signal Se.

In addition, as the display means TAF is now connected to the output of the divider 18a, and as the division rate N of this divider is preferably chosen equal to that (P) of the divider 26, the signal Sd is found, which has a frequency of 1 Hz, at the output of the divider 18a.

Thus, in this operating mode, the generating means 20 deliver to the division chain 14 an auxiliary signal Sr with a frequency P times higher than that of the output signal Se of the time base G (in this case 48 times since P = N and N = 48), but representative of the frequency of this signal Se and this thanks to the control of the generator means 20 on the basis of time G.

Therefore, the signal at the output of the division chain 14 has a frequency of the same P times higher (originally 1 Hz and now 48 Hz) and as the value P is equal to the value N, we find at the output from the divider 18a a signal of a frequency N times reduced, that is to say again equal to 1 HZ (that is to say the signal Sd).

The display means TAF being connected at this point, it functions as when it is used in normal mode, and the motor which advances by one step per second provides the control device 2 with detectable information.

This information is processed by this device which indicates to the controller or the watchmaker via a display means 3, whether the running of the watch is correct or not.

Furthermore, the divider 18b receiving at its input the signal Sd (1 Hz), the inhibition period is no more than 10 seconds (ie 1 x 10 since U = 10).

The periodicity T of the adjustment is therefore reduced.

In addition, inhibition occurs in a completely normal manner (undisturbed) since the division rate N x U (480) which manages the "rhythm" of inhibition has remained constant.

This inhibition is therefore always launched every 480 pulses received from the output signal of the division chain 14, but since this signal is faster (48 times) the time between these pulses is reduced and the inhibition period (measurement relative to time and not with respect to the number of pulses) is correspondingly shortened.

Consequently, it can be seen that thanks to this arrangement, in which the timepiece comprises generator means which are provided with servo means for slaving the frequency of the auxiliary signal Sr to that of the signal Se supplied by the time base G , and in which the generating means are arranged to be selectively connected to the junction between the time base G and the division chain 14 in order to shorten, during the control of the walk, the periodicity of adjustment, it is possible perform a reliable and error-free measurement without losing the time provided by the timepiece.

Of course, this device would be entirely satisfactory even if the switch 36 were omitted. This would require the possibility of setting the control device 2 on a control frequency P times higher and then reset the timepiece, which of course is not an optimal solution.

Claims (12)

1. Electronic timepiece of the type comprising :

   - a timebase (G) adapted to supply an output signal (Se) at a frequency constituting a time reference,

   - time display means (TAF) connected to the timebase (G) via a dividing chain (14) able to convert the output signal (Se) supplied by the timebase into a signal (Sd) at a divided frequency adapted to said time display means (TAF),

   - adjustment means (16) connected to said dividing chain (14) to adjust over a predetermined adjustment time interval any deviation between the frequency of said output signal (Se) and a nominal standard frequency (Sn), and

   - generator means (20) for generating an auxiliary signal (Sr) of much greater frequency than said output signal (Se), for the purpose of controlling the timepiece's pace,
   this timepiece being characterized in that said generator means (20) comprise frequency control means for subordinating the frequency of said auxiliary signal (Sr) to the frequency of the signal (Se) of the timebase (G), and in that the generator means (20) are arranged to be selectively connected, during control of the timepiece's pace, to the junction between said timebase (G) and said dividing chain (14) whereby said predetermined adjustment time interval is reduced.
2. Timepiece according to claim 1, characterized in that said generator means (20) comprise at least one phase comparator (22) and a variable-frequency oscillator (24).
3. Timepiece according to claim 2, characterized in that a first input of the phase comparator (22) is connected to the output of the timebase (G) to form said frequency control means, another input of this phase comparator (22) being connected to the output of said variable-frequency oscillator (24) whose frequency is controlled by said comparator (22).
4. Timepiece according to claim 2 or 3, characterized in that said generator means (20) further comprise a divider (26) arranged between the output of the variable-frequency oscillator (24) and the corresponding input of the phase comparator (22).
5. Timepiece according to claims 1, 2, 3 or 4, characterized in that the output of the variable-frequency oscillator (24) is selectively connectable to the dividing chain (14) when the output of the timebase (G) is correlatively connected to the phase comparator (22) and disconnected from said dividing chain (14).
6. Timepiece according to one of the preceding claims, characterized in that the variable-frequency oscillator (24) is a voltage-controlled oscillator connectable to the timepiece power supply.
7. Timepiece according to one of the preceding claims, characterized in that it comprises actuating means (30, 31, 32) enabling supply of the generator means (20) and simultaneously connection of the generator means, on the one hand, with the output of the timebase (G) to subordinate said generator means thereto and, on the other hand, with the input of the dividing chain (14).
8. Timepiece according to claim 7, characterized in that said actuating means comprise contact breakers (30, 31) and switches (32, 36) controllable by actuation of an externally accessible part of the timepiece, such as a winding stem.
9. Timepiece according to claim 7 or 8, characterized in that said actuating means comprise a contact breaker (30) arranged between the output of the timebase (G) and the input of the phase comparator (22), a contact breaker (31) arranged between the timepiece power supply and the supply terminal of the variable-frequency oscillator (24), and a switch (32) arranged between, in the one hand, the input of the dividing chain (14) and, on the other hand, selectively with the output of the timebase (G) and the output of the variable-frequency oscillator (24) respectively.
10. Timepiece according to one of the preceding claims, characterized in that it comprises a switch (36) adjacent the display means (TAF), this switch (36) connecting the display means (TAF) selectively to the input or the output of a divider (18a).
11. Timepiece according to claim 10, characterized in that the division ratio (N) of said divider (18a) is equal to the division ratio (P) of the divider (26) of the generator means (20) .
12. Timepiece according to one of claims 9 to 11, characterized in that it further comprises a divider (40) arranged between the output of the timebase (G) and the common junction of the contact breaker (30) and switch (32).

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