EP0744675B1 - Time measuring instrument particularly electric wrist watch of the analogue type - Google Patents

Description

The present invention relates to a time instrument, in particular a wristwatch, of the analog type supplied by an electrical energy source and comprising at least one recursive cycle indicator driven by a motor dedicated and an electronic circuit arranged to control all of the functions of the time instrument and in particular the movement of said indicator recursive cycle, this circuit comprising at least one voltage reference or internal resistance and a comparator designed to detect at least one level of predetermined load defined by the voltage or internal resistance of said source of electrical energy.

We know many watches with analog display or display digital, mainly of the liquid crystal type, which are provided with means for detecting the end of battery life.

For watches with digital display, the display includes a symbol becoming apparent as soon as the critical level is detected by measuring the internal voltage or resistance of the battery. We know that when the battery nearing the end of its life, its blood pressure drops and its internal resistance increases and the measurement of detection of the passage of their value below or beyond thresholds predetermined to detect the approach of the end of battery life.

For watches with analog display, there are other ways to make their owner attentive to the approach of the end of battery life. A death means is described in the Swiss patent n ° 616 046 in the name of CITIZEN WATCH CO Ltd, and includes an electronic circuit which causes "limping" or irregular oscillation of the second hand which advances four seconds every four seconds. In this same patent is described a complicated electromechanical mechanism including a symbol attached to the end of a needle and which becomes apparent through a window arranged in the dial called the date window and which is brought above the disc of date when the battery approaches its end of life.

Swiss Patent No. 616,046 in the name of Ebauches S.A. proposes to display the end of battery life by a disc placed below a specially designed dial window provided for this function, this disc being moved integrally with the kinematic chain of the analog display, the polarity of the quiescent state of the engine to be modified when displaying end of battery life.

Another embodiment is described in the European patent application published under n ° 0621 519 of ISA FRANCE S.A. The display of a position excess of a recursive display is generated by an independent motor. In this embodiment, it is necessary to ensure that before the end of the life of the stack, this excess position is not apparent, which amounts to skipping this state, whereas at the end of battery life, it is necessary to ensure the display of this surplus position excluding normal positions.

Other well-known embodiments are described in particular in the patents Swiss n ° 616 296, 616 046, 684 623. They all have at least one or the other of the faults described below.

Some provide a sometimes complex complementary mechanism for display a signal indicating the end of battery life.

Some require the creation of an additional window in the dial, which which modifies, even degrades, the traditional aesthetics of the watch.

In some cases, the application is limited because the display is directly linked to the main kinematic chain of the watch.

In other cases, extra space between the dial and the disc display is required which increases the size of the gauge.

Some systems are not reversible. The battery end of life display does not may not disappear after its appearance, and a battery exposed to cold may momentarily reach the detection thresholds, but at a temperature ambient it regains its properties of charged battery. We must then do disappear the end of battery display which only appeared momentarily.

Some systems are dependent on mechanical engineering parameters difficult to modify which does not allow adaptation of the duration of operation before a battery change, i.e. they cannot integrate technical progress in terms of increased longevity average of batteries and generalized reduction in consumption of movements.

Other systems use an excess position of a mobile at the expense information normally conveyed by this mobile. For exemple, the date display is hidden in favor of an end indication of battery life.

In addition, some systems are designed in such a way that the display of the approach of the end of battery life requires the implementation of means energy consumers, which has the negative effect of speeding up this approach.

Finally, systems that use the second hand are of course not applicable only on calibers providing such a needle, which is not generally not the case for calibers for ladies' watches.

The object of the invention is to remedy the drawbacks of the prior art and to propose a watch comprising means for indicating the imminent end of battery life without additional devices and easy to implement in usual constructions of watch movements.

This goal is achieved for a time instrument as defined in the preamble and characterized in that said electronic circuit is arranged to control a moving the recursive cycle indicator such as the apparent indication provided by this indicator in normal mode occupies a first position constant and that the apparent indication provided by the indicator in case of detection of a charge level lower than said predetermined charge level, occupies a second position offset from said first position constant.

According to a first main embodiment, the offset of said second position relative to said first position remains constant.

According to a variant, the apparent indication, when it occupies said second position, may be accompanied by the additional display of a symbol.

According to a second main embodiment, the offset of said second position relative to said first position is progressive and increases with the decrease in voltage or increase in internal resistance of the source of electrical energy.

According to a first particularly advantageous embodiment, the shifting of the second position is carried out in stages, each stage corresponding to a predetermined threshold of voltage or internal resistance of the source of electrical energy.

According to a second particularly advantageous embodiment, the shifting of the second position is carried out in stages, each stage corresponding to a separate indication which is automatically displayed in a predetermined time after detection of said predetermined charge level.

In these embodiments, each offset level corresponds to the complementary display of a different symbol and said symbol is associated with the indication carried by the recursive cycle indicator, placed on this indicator offset from the indication, in the direction of movement of the indicator.

According to a preferred embodiment, the electronic circuit is arranged for control the movement of the recursive cycle indicator so that reversible, the indication display being shifted in the event of detection of a charge level lower than said predetermined charge level and becoming again normal if a return to a charge level higher than this is detected predetermined charge level.

• la figure 1 représente une vue schématique illustrant une forme de réalisation préférée d'un instrument horaire selon l'invention,
• la figure 2 illustre l'affichage du quantième de la montre de la figure 1 lorsqu'elle marche en mode normal,
• la figure 3 illustre l'affichage du quantième lorsqu'elle marche en mode "fin de vie de pile",
• la figure 4 représente un graphe qui illustre l'évolution de la tension et de la résistance interne d'une pile au cours de sa vie,
• la figure 5 illustre une autre forme de réalisation où l'affichage du jour est décalé et accompagné d'un symbole pour signaler l'approche de la fin de vie de la pile,
• la figure 6 illustre une forme de réalisation où l'affichage du quantième est accompagné d'un symbole pour signaler l'approche de la fin de vie de la pile, et
• les figures 7A, 7B, 7C et 7D illustrent une variante dans laquelle on affiche par des moyens différents une approche progressive de la fin de vie de la pile.

The invention will be better understood with reference to the description of a preferred embodiment given by way of nonlimiting example and to the appended drawings in which:

• FIG. 1 represents a schematic view illustrating a preferred embodiment of a time instrument according to the invention,
• FIG. 2 illustrates the display of the date of the watch in FIG. 1 when it is operating in normal mode,
• FIG. 3 illustrates the display of the date when it operates in "end of battery life" mode,
• FIG. 4 represents a graph which illustrates the evolution of the voltage and of the internal resistance of a battery during its life,
• FIG. 5 illustrates another embodiment where the day display is shifted and accompanied by a symbol to signal the approach of the end of life of the battery,
• FIG. 6 illustrates an embodiment in which the date display is accompanied by a symbol to signal the approach of the end of life of the battery, and
• FIGS. 7A, 7B, 7C and 7D illustrate a variant in which a progressive approach to the end of battery life is displayed by different means.

With reference to FIG. 1, the watch shown diagrammatically includes a electric power source 10 consisting of a battery which powers a electronic circuit and, through this circuit, two electric motors 11 and 12 which operate the hour hands 13, minutes 14 and seconds 15 for motor 11 and a date disc 16 for which is motor 12. The date disc has the numbers 1 to 31 arranged for example on a circle centered on the axis of the needles and each number corresponding to a day of the month, appears successively in a window 17 provided in the dial 18 of the watch.

The control link between the motor 11 and the needles 13, 14 and 15 as well that between the motor 12 and the date disc 16 are respectively represented by lines 19 and 20 in phantom.

Note that the date "15", which appears in the window 17, is perfectly centered, which means, as will be explained later, that the battery is charged and the watch operates in normal mode.

The electronic circuit mainly comprises a quartz oscillator 21 associated with a microprocessor 22 of the watchmaking type which controls directly the two motors 11 and 12, as well as a circuit 23 for controlling the voltage of the battery. This control circuit essentially comprises a comparator 24, a special circuit 25, known per se, for example from Swiss patent application no. 651,999, British publication 2,111,223 or Swiss Patent No. 672,391 arranged to store for example a reference voltage threshold, or a internal resistance threshold and two resistors 26 and 27 called respectively resistance of the divider bridge and resistance of the bridge. These two resistors 26 and 27 are connected by one of their common terminals 28 to a positive input 29 of comparator 24. The other terminal of resistor 27 is connected to ground T. The other terminal of the resistor 26 is connected to the positive terminal of the battery. The negative input 30 of the comparator 24 is connected to the special circuit 25 which is also connected to ground T by its other terminal. Comparator output 31 24 is connected to microprocessor 22.

In this embodiment, the recursive parameter is the date. It might be replaced by any other recursive parameter such as for example the day, the week, month or year. The disc with the indication of this parameter recursive is driven by an independent motor by a kinematic chain which his own. The movement of information to contiguous information is generated by the motor which is supplied by a number of + N or -N not. This number is preferably between 10 and 300.

The control circuit 23 is arranged to detect the voltage U of the battery or its internal resistance Ri and to compare it with a predetermined threshold value. When the effective value of the internal voltage or resistance reaches these respective threshold values, the circuit 23 transmits appropriate information to the microprocessor 22 which controls the motor 12 by a number of pulses + M or -M distinct from the number + N or -N corresponding to normal mode. In practice, if N is for example equal to 100 pulses, M will be equal to Nn where n is advantageously equal to 10 pulses. This has the effect of causing an offset of the recursive display, in such a way that the information displayed, in this case the date, remains perfectly visible in the window 17, but is moved relative to its normal position for provide the wearer of the watch with additional information which he will interpret as an indication of the end of battery life.

The offset may, where appropriate, be accompanied by a symbol or sign particular which has the function of attracting even more the attention of the wearer on the information already implicitly contained in the display offset.

By admitting that the displacement of the disc 16 of the date, day, month or of the year constituting said recursive parameter, is proportional to the number of not traversed by the motor 12 or by supply pulses supplied by the microprocessor 22, the apparent surface displayed corresponds to the proportion n / N of the total area of the counter. If N = 100 and n = 10, the apparent surface useful for displaying the end of battery life by means of a symbol completing the offset is 10% while the area useful for displaying the parameter recursive remains 90%, which is more than enough for this information remains clearly legible.

FIG. 2 shows an enlarged view of the display of a date 40, in this case on the 15th day, in window 17, when the watch is running in normal mode.

Figure 3 shows this display when the battery reaches the end of its life. Firstly the date 40 is shifted upwards, and on the other hand, under the 15th day of month appears a line 41 which is hidden in normal mode. In this case, the displacement of the date disc corresponds to N - n not, the number n of no missing being responsible for the observed lag.

In this embodiment, the visualization or signaling of the end of life of the battery is transmitted to the watch user by two complementary signs: one is the date shift which is considered the main sign, the other is line 41 which could also be replaced by any other sign or ideogram at the choice of the manufacturer.

FIG. 4 represents the evolution of the voltage U _p of the battery of a watch and of its internal resistance R _i as a function of time t. The curve 50 which corresponds to the voltage varies over time. This voltage is substantially constant and has a value U ₀ during a time interval which can be several years. It decreases more and more quickly when the battery approaches its end of life, that is to say when it reaches the end of charge. On this curve are for example identified two thresholds U _A and U _B which are reached respectively at time t _A and at time t _B separated by a time interval Δt1. There are in fact several approaches leading to the display of the end of life of the battery. One of these approaches may consist in detecting the first threshold U _A and in carrying out a display as described with reference to FIG. 3. Another approach consists in detecting the first threshold U _A and in proceeding as above, then detecting the threshold U _B to reinforce this display, for example by increasing the date shift. A third approach may consist in detecting other thresholds U _C , U _D , etc. and to increase the offset each time and possibly to complete each offset by displaying a sign or an ideogram.

Finally, a fourth approach may consist in detecting only a single threshold U _A and in displaying a first offset, whether or not accompanied by a sign at time t _A corresponding to this detection, then in displaying one or more progressive offsets also whether or not accompanied by signs after time intervals Δt1, Δt'1, Δt "1 etc. these time intervals may be equal or preferably decreasing.

The same observations apply to the internal resistance R _i which is substantially constant and equal to R _i0 as long as the battery is charged as shown in curve 51 of FIG. 4 and which increases when the battery approaches its end of life. To detect this end of life, it is possible to detect a threshold R _iA of this internal resistance and proceed to display the offset date. As before, the offset can be increased when a second threshold R _{iB is detected} . The detection of the two thresholds is separated by a time interval Δt2 which could also serve as a basic reference for determining when the offset of the date display must be increased. As before, the number of detected thresholds is not limited to two and the offset as well as the display of signs can be progressive.

Various embodiments of the display of signs indicating the end of life of the battery are illustrated by the following figures.

Figure 5 displays the day inside a window 52. It can be seen that the day displayed, in this case LUNDI is not centered laterally inside the counter and it is also accompanied by a point 53. We find in this realization of both the offset and the complementary sign.

Figure 6 shows the offset display of the day, in this case the fifteenth day of the month shifted in window 17. It is accompanied by a point 53 similar to that of figure 5.

We will note in these two examples, as elsewhere in that of FIG. 3, that the offset is always carried out in the direction of movement of the support, that is to say, the date disc and the day disc. The sign is associated with the indication, but only appears when this indication is shifted. In normal operation the sign is masked by the dial and does not appear in the window.

FIGS. 7A, 7B, 7C, and 7D illustrate a progressive shift in the display of the date and a progressive variation in the display of complementary signs. Figure 7A shows the window 17 in which the calendar "29" appears perfectly centered. The battery is charged, the watch operates in normal mode. Figure 7B shows the window 17 in which the date "30" appears offset and accompanied by a sign 60 having the shape of a first rectangle. This offset display corresponds to the detection of a threshold U _A or R _iA of the voltage or of the internal resistance of the battery.

Figure 7C shows the window 17 in which the date "13" appears offset, the offset being amplified relative to that of the date 30 of Figure 7B, and accompanied by a second rectangle 61 adjacent to rectangle 60 and larger than this latest. This display can correspond to the detection of a second voltage threshold U _B or of a second internal resistance threshold R _iB . However, it can also appear at the end of a time interval Δt1 or Δt2 equal for example to 14 or 15 days which separate the date "30" from the date "13" of the following month.

Figure 7D shows the window 17 in which appears the date "20" even more strongly offset and accompanied by a third rectangle 62 attached to the previous ones and larger than the two rectangles 60 and 61. This display may be the result of detecting a third voltage threshold or internal resistance or appear automatically after a time interval predetermined after the previous offset display.

In this case, this display appears seven days after the display shown by Figure 7C.

Various variants are possible both in terms of display mode and in terms of detection mode. Each achievement is a particular combination of these different modes.

One of the advantages of this system compared to many solutions of the art previous, is that it is reversible, in other words that the "defect of centering" the indication of the recursive cycle appears as soon as the charge level becomes insufficient and disappears as soon as it becomes sufficient. This quality is notably interesting in the charge area close to the predetermined charge level below which the offset occurs. Indeed, some external parameters, such as in particular the temperature, can have an influence on the state of charge. A significant drop in temperature usually causes a fall voltage and an increase in the internal resistance of the battery. So when the watch is worn in a place where the temperature is low and when the battery is close to its "critical" charge level, the voltage threshold or internal resistance is detected prematurely and causes the shift of display.

If the watch is later worn in a place where the temperature is higher high, the voltage rises and the internal resistance drops and exceeds again the threshold values. The electronic circuit is designed so that the pulses offset are compensated. For example, if the display offset was generated by a number n of missing pulses, the total number of pulses supplying the corresponding motor 11 being N-n, it would be necessary supply this motor with N + n pulses so that the next step is carried out with the required offset compensation.

Claims (9)

1. Time-keeping instrument, in particular an analog-type wrist watch, powered by a source of electric energy and comprising at least one indicator of a recursive cycle driven by a dedicated motor and an electronic circuit adapted so as to control all the functions of the time-keeping instrument and in particular the movement of said indicator of recursive cycle, this circuit comprising at least a reference of voltage or of internal resistance and a comparator designed so as to detect at least a predetermined level of charge defined by the voltage or the internal resistance of said source of electric energy, characterized in that said electronic circuit is adapted to control a movement of the indicator of recursive cycle such that the apparent indication furnished by this indicator in its normal mode occupies a first constant position and that the apparent indication furnished by the indicator in case of detection of a level of charge less than said predetermined level of charge occupies a second position displaced with respect to said first constant position.
2. Time-keeping instrument according to claim 1, characterized in that the displacement of said second position with respect to said first position remains constant.
3. Time-keeping instrument according to claim 1, characterized in that the apparent indication, when it occupies said second position, is accompanied by the complementary display of a symbol.
4. Time-keeping instrument according to claim 1, characterized in that the displacement of said second position with respect to said first position is progressive and increases with the decrease of the voltage or the increase of the internal resistance of the source of electrical energy.
5. Time-keeping instrument according to claim 4, characterized in that the displacement of the second position is effectuated by stages, each stage corresponding to a predetermined threshold of voltage or of internal resistance of the source of electric energy.
6. Time-keeping instrument according to claim 4, characterized in that the displacement of the second position is effectuated by stages, each stage corresponding to a distinct indication which is automatically displayed within a predetermined time limit after the detection of said predetermined level of charge.
7. Time-keeping instrument according to claims 5 and 6, characterized in that each stage of displacement corresponds to the complementary display of a different symbol.
8. Time-keeping instrument according to claim 7, characterized in that said symbol is associated with the indication carried by the indicator of the recursive cycle, provided on this indicator in a displaced manner with respect to the indication, in the direction of the movement of the indicator.
9. Time-keeping instrument according to claim 1, characterized in that the electronic circuit is adapted to control the movement of the indicator of the recursive cycle in a reversible manner, the display of the indication being displaced in case of detection of a level of charge less than said predetermined level of charge and becoming normal again in case of detection of a return to a level of charge greater than this predetermined level of charge.

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