EP0759584A1 - Synchronisation means with time zone detector - Google Patents

Abstract

The contact wheel, driven by the hour wheel of the movement, carries an axisymmetric central contact spring with four arms (4,6,8,10) touching conductive tracks (T1-T5) on a printed circuit board. The geometry of the arms ensures a periodic variation of the interconnections between the tracks. Three tracks (T1-T3) subtending equal angles of about 50 degrees at the centre are distributed uniformly around one half of the ring. Three pairs of tracks (T4,T5) individually subtending about 20 degrees are arranged around the other half. An electronic control signal processor memorises the contact configuration in the initial position, and detects any one-hour movement of the wheel.

Description

The present invention relates to a synchronization device for an electronic timepiece comprising an analog display for displaying certain time information and an electronic counter for storing some of said time information, this synchronization device being intended to synchronize the display with the counter. More specifically, the invention relates to such a device for a timepiece having combined digital and analog displays, the synchronization device being intended to synchronize these displays in the event of a change of time zones.

Such a synchronization device has already been proposed. Indeed, patent application FR-A-2 484 101 relates to a timepiece comprising a synchronization device which comprises a wheel carrying the minute or second hand on which two conductive strips rub. Electrical contact means are provided on one face of the wheel to raise and thus periodically short-circuit the two strips.

However, if the wheel is turned quickly, mechanical bounces can occur, thus hindering the short circuit. In addition, the detection accuracy and the correction which can still be carried out to compensate for any loss of information due to rebounds, are very limited.

Patent CH-B-653 846 also describes a synchronization device for a timepiece, making it possible to synchronize, in the event of a change in the date, an analog display with an electronic counter contained in the timepiece. Here, the synchronization device comprises a first annular cam which is located around the barrel of the wheel of the hours. A conductive strip, mounted on the planar annular part of the cam, has an inclined point which extends towards a conductive track connected to the electronic device of the timepiece. Three spacing pads are planted in the cam board and are distributed circularly in positions at 120 °. When the protruding studs are opposite the notches arranged in a second rotating cam located below the first cam, the first cam carrying the studs will be moved downward under the effect of a tinsel spring. The conductive strip is thus led to the conductive track. Such an arrangement also has the problem that, because of the displacement of the first cam with the conductive strip, mechanical rebounds occur when the second cam carrying the notches rotates rapidly, leading to a loss of information without the possibility of compensation or correction. . In addition, this system is difficult to adapt to detect changes in time zones.

The object of the present invention is to remedy these drawbacks of the prior art by a new and inventive solution which is set out in the claims.

The synchronization device proposed by the invention consists of a "pseudo-absolute" coordinate system, that is to say that by knowing the starting position, the position of the hand indicating the time information can be found with great precision because of a glut of information.

For this purpose, the hour wheel drives a contact wheel on which is fixed a contact spring with several arms. The arms make contact with conductive tracks distributed in a particular arrangement on the printed circuit associated with the synchronization device and with an electronic device for processing the control signals. By the geometry of the arms, the tracks are linked periodically in different configurations, for example every twenty minutes. The series of combinations forming the different possible configurations is repeated periodically. The electronic device for developing control signals, for example a microprocessor, stores the initial position corresponding to a certain configuration of the contacts, and, as the series of combinations is given, each movement of the hour wheel, for example, twenty minutes can be detected.

Thanks to the characteristics of the invention, the synchronization device can better detect changes in states while requiring less space for the electronic circuit connected to the device. Thus, the bulk, important insofar as the synchronization device is used in a timepiece, in particular a wristwatch, can remain minimal.

• la figure 1 représente schématiquement une vue de haut d'une roue de contact comportant un ressort contacts ayant des bras conducteurs du dispositif de synchronisation selon l'invention,
• la figure 2 montre plus en détail le ressort contacts avec ses bras conducteurs de la figure 1,
• la figure 2a montre en vue de coupe schématique un bras conducteur du ressort contacts de la figure 2,
• la figure 3 représente schématiquement la disposition des pistes de contact sur un circuit imprimé disposé sous la roue de contact de la figure 1,
• la figure 4 représente schématiquement les combinaisons faites entre le ressort contacts avec les pistes de contact,
• la figure 5 représente schématiquement la série des dix-huit combinaisons des contacts possibles, et
• la figure 6 montre un diagramme de changements d'état de l'affichage analogique à partir d'un état initial.

Other advantages and characteristics of the invention will emerge more particularly from the following description in which an embodiment of the object of the invention is described, by way of example only, with reference to the accompanying drawings, in which :

• FIG. 1 schematically represents a top view of a contact wheel comprising a contact spring having conducting arms of the synchronization device according to the invention,
• FIG. 2 shows in more detail the spring contacts with its conductive arms of FIG. 1,
• FIG. 2a shows in schematic sectional view a conductive arm of the contact spring of FIG. 2,
• FIG. 3 schematically represents the arrangement of the contact tracks on a printed circuit placed under the contact wheel of FIG. 1,
• FIG. 4 schematically represents the combinations made between the contact spring with the contact tracks,
• FIG. 5 schematically represents the series of eighteen combinations of the possible contacts, and
• FIG. 6 shows a diagram of changes of state of the analog display from an initial state.

FIG. 1 shows a contact wheel 1 of the synchronization device D according to the invention. The device D according to the invention is intended to be used in a timepiece to synchronize the digital display of a time zone with the analog display of the current time. A contact spring 2, in this example having four arms 4, 6, 8 and 10, is fixed to the contact wheel 1. The wheel 1 has a center C located on its axis of symmetry and is associated with a train of the part of watchmaking. The wheel 1 is arranged to be driven by the hour wheel, not shown, of the timepiece. In the example, the contact wheel is a twelve-hour wheel, but this wheel can also be a twenty-four hour wheel. The way of driving the wheel 1 by the clockwork gear can be carried out in a manner known to those skilled in the art which will not be described in detail here.

The contact spring 2 is mounted axi-symmetrically with respect to the wheel 1 in the center C of the latter, and is shown in more detail in FIG. 2. The spring 2 is made of a conductive material and here comprises two pairs of arms 4, 6 and 8, 10 which extend longitudinally from the center C towards the outside, with an angle of symmetry Ω which is here 180 °. However, the spring 2 may include several pairs of arms taking advantage of the same geometries. The angle of symmetry Ω thus depends on the number of pairs of arms. The symmetries would then change at 120 ° for three pairs, 90 ° for four pairs, and so on. The spring 2 comprises a hub 2a having a central opening 3 centered on the point C allowing the mounting of the spring 2 on the contact wheel 1 in a manner also known to those skilled in the art.

Figure 2a shows a sectional view of an arm of the spring 2 of Figure 2. The pairs of conductive arms 4, 6 and 8, 10 are electrically connected to each other by means of the hub 2a. Each arm is identical to one another. In this example, each arm 4, 6, 8, 10, only one being shown in FIG. 2a, comprises three different parts. A first part, referenced by 11, forms together with the first parts of the other arms the hub 2a. This inner part 11, coming from the center of the spring 2, is associated with a second central part 12 which, preferably, is slightly inclined relative to the first part 11. A third part 13 forms the free end of the arm and is still , preferably, inclined relative to the central part 12 of the arm. However, it is understood that the second part 12 and the free end 13 can be replaced by a single part having an inclination equal to the total inclination of the two parts 12 and 13. The free end 13 has an inclined point which s' extends to a contact track to make friction contact therewith as will be explained in more detail below.

The two arms of the same pair have an angular offset α between them. The two pairs of arms of the embodiment described here are arranged symmetrically with respect to the center C. The angle α being in this example 40 °, but it can also be chosen different. Indeed, the conditions to be fulfilled by the arrangement of the arms, and therefore the limit values of the angle α, depend on the arrangement of the contact tracks as will also be explained in more detail below.

The contact tracks are shown diagrammatically in FIG. 3. The tracks are deposited, by a method well known to those skilled in the art, on a printed circuit placed under the contact wheel 1 in FIG. 1. The circuit is associated with the synchronization device D according to the invention so that the latter is connected to an electronic device for developing control signals P, for example a microprocessor intended to receive electrical pulses which are generated when the arms 4, 6, 8, 10 come into contact with the contact tracks.

The tracks form contact pads arranged circularly and defining a ring A. As can be seen in FIG. 3, the ring A comprises several different pads, here three kinds of different pads T1 or T2 or T3 and T4 and T5, which are each separated from each other by a separating space having an angle at the center ε. The length of a track is defined by the angle at the center φ. We still define the sum of the length of a track and the separating space as the repetition angle γ, therefore $$\text{γ = φ + ε.}$$

FIG. 3 shows three first distinct contact areas, called detection areas referenced by T1, T2 and T3, each having a length φ ₁ which in this example is of the order of 50 °, therefore φ ₁ > α. The distance between each of these detection tracks is ε ₁ which is in this example of the order of 10 °. The first contact pads T1, T2, T3 are distributed regularly over the first half (180 °) of the ring A.

. Les plages T4 et T5 sont espacées l'une de l'autre d'une distance ε₂, ici de l'ordre de 10°. Les deuxièmes plages de contact T4 sont reparties régulièrement sur la deuxième moitié de l'anneau A. Ces plages T4 fonctionnent également comme des plages de détection, mais elles peuvent aussi fonctionner comme plages d'alimentation comme cela sera expliqué plus en détail plus loin. Les troisièmes plages de contact T5, sont également reparties régulièrement sur la deuxième moitié de l'anneau A. Les troisièmes plages T5 sont des plages d'alimentation qui, ensemble avec une des plages de contact T1, T2, T3 ou T4, engendrent une impulsion au moment où les bras conducteurs 4, 6, 8, 10 rentrent en contact de friction avec les plages, comme sera expliqué plus en détail ci-après. Dans le mode de réalisation représenté à la figure 3, les troisièmes plages de contact T5 sont reparties alternativement vis-à-vis des plages de contact T4.The ring A further comprises on its other half, called the second half, three second and three third contact pads, referenced T4 and T5. The length of each of the second ranges T4 is φ ₂ , and of each of the third ranges is φ ₃ , φ ₂ and φ ₃ are here of the order of 20 °, therefore ${\text{φ}}_{\text{2}}{\text{= <figure-callout id="3" label="φ" filenames="imgf0001.png" state="{{state}}">φ</figure-callout>}}_{\text{3}}\text{<α}$

. The areas T4 and T5 are spaced from each other by a distance ε ₂ , here of the order of 10 °. The second contact pads T4 are distributed regularly over the second half of the ring A. These pads T4 also function as detection pads, but they can also function as supply pads as will be explained in more detail below. The third contact pads T5, are also distributed regularly over the second half of the ring A. The third contact pads T5 are supply pads which, together with one of the contact pads T1, T2, T3 or T4, generate a pulse when the conductive arms 4, 6, 8, 10 come into frictional contact with the pads, as will be explained more in detail below. In the embodiment shown in FIG. 3, the third contact pads T5 are distributed alternately with respect to the contact pads T4.

comme il y a des deuxièmes et des troisièmes plages de contact.
Ce paramètre m correspond au nombre de phases, ou heures, dans la durée d'un contact, comme cela sera expliqué ci-après. La figure 3 montre l'exemple avec Ω=180° et où m=3, donc où il y a trois pistes d'un même contact sur une moitié de l'anneau A, à savoir pour les premières plages il y a trois contacts T1, T2 et T3 sur la première moitié, et sur la deuxième moitié de l'anneau A il y a six contacts, pour les deuxièmes plages il y a trois contacts T4, et pour les troisièmes plages il y a trois contacts T5.As the arms are arranged symmetrically, in this example, at 180 °, the repetition angle γ must be repeated an integer m of times in the angle of symmetry Ω, which is here 180 °. Thus, the following conditions are obtained: $$\begin{array}{c}\begin{array}{c}\text{if φ ≥ α: m · γ = Ω, and}\\ \text{if φ <α: 2m · γ = Ω,}\end{array}\end{array}$$

as there are second and third contact areas.
This parameter m corresponds to the number of phases, or hours, in the duration of a contact, as will be explained below. Figure 3 shows the example with Ω = 180 ° and where m = 3, so where there are three tracks of the same contact on one half of the ring A, i.e. for the first ranges there are three contacts T1, T2 and T3 on the first half, and on the second half of ring A there are six contacts, for the second areas there are three T4 contacts, and for the third areas there are three T5 contacts.

The particular arrangement of tracks T1 to T5 relating to the arm 4, 6, 8, 10 makes it possible, in fact, to obtain an extension of the contact time between an arm and a track. Thus, the resolution of the detection is improved. This extension depends on the angles chosen. In general we can say that the following two conditions are valid: $$\begin{array}{c}\begin{array}{c}\begin{array}{}\text{(1);}\text{for φ <α: α = n · γ-φ = (n-1) · φ + n · ε}\end{array}\\ \begin{array}{}\text{(2);}\text{for φ ≥ α: α = m · (γ / (m-1)) - φ, where m> 2}\end{array}\end{array}\end{array}$$

. Pour l'exemple donné, φ₁ doit donc remplir la condition (2), tandis que φ₂ et φ₃ doivent remplir la condition (1). Ainsi, on obtient n = 2 et m = 3.The parameter (n-1) corresponds to the number of contact pads between two arms, that is to say in the angle α. For condition (1), we understand that when this condition is met, the length of the electrical contact is extended to 2 · φ, and for condition (2), the length of the electrical contact is extended to (α + φ). Thus, for the example given, in which 10 ° corresponds to twenty minutes, as will be explained in more detail below, the length of the contact is 40 + 50 = 90 °. As this corresponds to three hours, the parameter has the value "3". In Figure 3, we see that φ ₁ > α, and that ${\text{<figure-callout id="2" label="φ" filenames="imgf0001.png" state="{{state}}">φ</figure-callout>}}_{\text{2}}{\text{= <figure-callout id="3" label="φ" filenames="imgf0001.png" state="{{state}}">φ</figure-callout>}}_{\text{3}}\text{<α}$

. For the example given, φ ₁ must therefore fulfill condition (2), while φ ₂ and φ ₃ must fulfill condition (1). Thus, we obtain n = 2 and m = 3.

The operation of the synchronization device D according to the invention is as follows.

All of the arms 4, 6, 8, 10 and the contact pads T1 to T5 form a time zone detector of the synchronization device D according to the invention. The change from one time zone to another is carried out by the user in a known manner, for example by pulling the stem of the timepiece comprising the device D according to the invention and then advancing the analog display , for example the hour hand. The analog display is set to the time chosen by the user, and the digital display of the time zone, which shows for example only the corresponding hour digit, must therefore be synchronized with the analog display modified by the synchronization device D according to the invention.

To this end, the electronic device for developing control signals, such as a microprocessor P, reads the coordinates of the position of the contact wheel 1 at the time when the stem of the timepiece is pulled to modify the analog display. Thus, the configuration of the generated pulse states is memorized. Analog and digital displays must be synchronized. By changing the analog display, the position of the contact wheel 1 is therefore modified in a corresponding manner. The arms 4, 6, 8, 10 will generate a series of pulses when they come into contact with the contact tracks T1 to T5. These pulses together form codes giving information corresponding to the information relating to time provided by the analog display.

The duration of a state defines the resolution of the detection and therefore depends on the geometry of the arms and contact tracks. For example, for the geometry shown in Figures 1 and 3, the tracks will be connected in different configurations every twenty minutes, which corresponds to a movement of ten degrees. However, it is understood that for a geometry different from that shown here, a change of state can last more or less long than twenty minutes or ten degrees. The resolution is determined by the desired result by considering physical and electronic restrictions of the synchronization device, such as the space available, and the consumption of the electronics.

In this example, the contact wheel 1 is a twelve-hour wheel. As the arms, which are associated with the contact wheel 1, have a symmetrical geometry, the sequence of the changes of states generated, that is to say the different possible configurations, will be repeated every six hours (180 ° ). In the example, we would still like to detect a change of state of twenty minutes. For this, we need three states per hour, and eighteen states in total. This therefore requires five different contacts (2 ⁵ = 32> 18).

FIG. 4 schematically represents several combinations of the arms of the contact spring 2 with the tracks T1 to T5. The starting position in this example is 12 noon. We see that thus the tracks T3 and T5 are linked together (Figure 4a). If the position of the analog display is advanced by one hour, the tracks T1, T3 and T4 will be linked (Figure 4b). By advancing another hour, tracks T1 and T5 will be linked (figure 4c), and after another hour, tracks T1, T2 and T4 will be linked together (figure 4d).

FIG. 5 schematically represents the series of eighteen combinations of the possible contacts for the example described above. We see that every ten degrees there is a change of state. The combination T1 = 0 and T2 = 0 and T3 = 0 is considered to indicate an error of device D.

. Toutefois, comme on peut voir à la figure 4b ou 4d, la piste T5 n'est pas toujours reliée aux autres pistes. Dans ce cas, c'est la piste T4 qui prend le rôle de piste d'alimentation. Au fait, T4 est toujours mis en sortie, à la tension V_dd. Uniquement pendant le moment de la lecture par le microprocesseur P, T4 est mis en entrée. Pour ceci on connecte le contact T4 à une porte Entrée-Sortie (I/O) du microprocesseur P. Si T4 n'est pas à la tension V_dd, la piste T5 n'est pas contactée. Ainsi, le contact T5 est utilisé comme une "pseudo-entrée" grâce à laquelle on obtient les cinq contacts nécessaires pour détecter les 18 états.In order for the microprocessor P to be able to read the states of the input contacts T1, T2, T3, the latter must be supplied, that is to say that a connection is required between a detection input contact T1, T2 or T3, and the power contact T5. To this end, track T5 is set to a supply voltage V _dd , therefore ${\text{T5 = V}}_{\text{dd}}$

. However, as can be seen in Figure 4b or 4d, track T5 is not always connected to the other tracks. In this case, the T4 track takes the role of feed track. In fact, T4 is always output, at the voltage V _dd . Only during the time of reading by the microprocessor P, T4 is put in input. For this, contact T4 is connected to an Input-Output (I / O) gate of microprocessor P. If T4 is not at voltage V _dd , track T5 is not contacted. Thus, the contact T5 is used as a "pseudo-input" thanks to which we obtain the five contacts necessary to detect the 18 states.

Thanks to the particular use of the contact T4, the detection resolution is increased without the need for additional tracks increasing the size of the device D according to the invention. It is understood that thus there are three different possibilities for supplying the contacts, that is to say by T4 and T5, by T5, or by T4.

Advantageously, the electrical contacts can be described by hexadecimal numbers. By giving the state T1 "high" the value "4", the state T2 "high" the value "2", the state T3 "high" the value "1", the state T4 "high" the value 2, and the state T5 "high" the value "1", the eighteen possible states are the following (always according to figure 4 and 5): state no. 1 2 3 4 5 6 7 8 9 T1 + T2 + T3 1 1 1 5 5 5 4 4 4 T4 + T5 1 3 2 2 3 1 1 3 2 state no. 10 11 12 13 14 15 16 17 18 T1 + T2 + T3 6 6 6 2 2 2 3 3 3 T4 + T5 2 3 1 1 3 2 2 3 1

The device for developing the control signals also comprises means for analyzing the states read by the microprocessor P. Of course, this analysis must react reasonably to each movement.

FIG. 6 shows a diagram of changes of state of the analog display starting from the initial state no. "9". It is understood that the digital display does not necessarily have to change with each movement of the analog display. If, for example, state 9 is read and then stored by the microprocessor P, states 8 or 10 may just be a very small movement of the hour hand of the analog display, see Figure 6a. A single change in a state is therefore not considered to be a defined movement. The memorized state then remains the old state. In the worst case, movements of almost forty minutes or almost twenty degrees are therefore not accepted as a jump of the hour hand requiring synchronization of the digital display, see Figure 6b.

In fact, since the change of an hour corresponds in principle to three changes of state of twenty minutes the movement of a change of one hour which is detected and which requires synchronization of the displays, corresponds to a change from two to four states, depending on the starting position of the hour hand. The minimum angle which is considered to jump by one hour would therefore be a little more than forty minutes or twenty degrees. In the worst case, the maximum angle is then just under 100 minutes or 50 degrees.

In analogy, we can analyze a jump of two hours from the hour hand of the analog display. Indeed, a movement or a jump of two hours which must be detected therefore corresponds to a movement of five to seven states. The minimum angle which is considered a jump of two hours would therefore be a little more than eighty minutes or forty degrees. The maximum angle considered a two hour jump will be just under 160 minutes or 80 degrees.

It should be noted that a change of more than seven states can no longer be interpreted correctly due to an uncertainty in the direction of the movement. Indeed, even if it is clear that such a change will correspond to a jump of three hours, we know that the detection of three hours corresponds to a change of eight to ten states. However, a change of ten states can no longer be detected, because it is no longer possible to determine the direction in which the hour hand will have moved.

Of course, the invention is not limited to the particular embodiment described above, which is given only by way of non-limiting example with respect to the subject of the invention.

Claims (7)

Synchronization device (D) for an electronic timepiece which comprises a time base, a gear train, an analog display driven by said gear train to display time information, and an electronic counter for storing some of said information, said synchronization device being intended to synchronize said display with said counter, characterized in that it comprises: - a contact wheel (1) arranged to be driven by said gear train, and comprising at least two pairs of conductive arms (4, 6; 8, 10) electrically connected together and which extend longitudinally from the axial center (C) from this wheel (1) to contact pads (T1, T2, T3, T4, T5) located on an electronic circuit arranged below said wheel (1), said pairs of arms being arranged symmetrically with respect to said center (C ) with an angle of symmetry Ω between each pair, the two arms of the same pair (4, 6; 8, 10) having an angular offset α, - an electronic control device (P) connected to said circuit and associated with said synchronization device (D), - said contact pads (T1, T2, T3, T4, T5) being arranged circularly and defining a ring (A), the length of each of said pads having an angle at the center φ, said pads being separated from one of the other by an angle at the center ε, and having a repeat angle $\text{γ = φ + ε}$

, the angle of repetition γ repeating an integer m of times in the angle of symmetry Ω when φ ≥ α, and the angle of repetition γ repeating an integer 2m of times in the angle of symmetry Ω when φ <α, and comprising - m first distinct detection contact pads (T1, T2, T3) being distributed regularly over a first half of said ring (A), and having a length φ ₁ which is greater than or equal to said angle α, and - m second (T4) and m third (T5) separate contact pads being distributed regularly and alternately over a second half of said ring (A), each second pad having a length φ ₂ and each third pad having a length φ ₃ , these lengths φ ₂ and φ ₃ being less than said angle α, in order to connect two tracks with said arms (4, 6; 8, 10). Synchronization device (D) according to claim 1, characterized in that said hour wheel (1) is a twelve hour wheel making one revolution in twelve hours. Synchronization device (D) according to claim 1, characterized in that said hour wheel (1) is a twenty-four hour wheel making one revolution in twenty-four hours. Synchronization device (D) according to any one of the preceding claims, characterized in that the angular offset α between the two arms of the same pair (4, 6; 8, 10) is forty degrees. Synchronization device (D) according to any one of the preceding claims, characterized in that said arms (4, 6; 8, 10) constitute a contact spring (2) mounted axi-symmetrically with respect to said hour wheel (1 ). Synchronization device (D) according to any one of the preceding claims, characterized in that each arm has a free end (13) which is inclined relative to the plane in which the said hour wheel (1) is located. Synchronization device (D) according to any one of the preceding claims, characterized in that said second contact pads (T4) are connected to an input-output door of said electronic control device (P) to function as detection ranges and that supply ranges.

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