CH688950GA3 - Synchronization device of an analog display with an electronic counter in a timepiece. - Google Patents

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 of 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 hour wheel. 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 DEG. 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 “pseudoabsolute” coordinate system, that is to say that knowing the starting position, the position of the hands indicating the time information can be found with a high accuracy due to an overabundance of information.

Thus, the invention relates to a synchronization device 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 arranged to be driven by said gear train, and comprising at least two pairs of conductive arms electrically connected together and which extend longitudinally from the axial center of this wheel towards contact pads located on an electronic circuit arranged in below said wheel, said pairs of arms being arranged symmetrically with respect to said center with an angle of symmetry OMEGA between each pair, the two arms of the same pair having an angular offset alpha, an electronic control device connected to said circuit, the synchronization device comprises said control device, - Said contact pads being arranged circularly and defining a ring, the length of each of said pads having an angle at the center phi, said pads being separated from each other by an angle at the center epsilon, and having an angle of gamma repetition = phi + epsilon, the gamma repetition angle repeating an integer m of times in the OMEGA symmetry angle when phi> / = alpha, and the gamma repetition angle repeating an integer 2 m of times in the angle of symmetry OMEGA when phi <alpha, and comprising m first distinct contact areas of detection being distributed regularly over a first half of said ring, and having a length phi 1 which is greater than or equal to said angle alpha, and m second and third distinct contact pads distributed regularly and alternately over a second half of said ring, each second pad having a length phi 2 and each t third range having a length phi 3, these lengths phi 2 and phi 3 being less than said angle alpha, in order to connect two tracks with said arms.

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.

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 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 OMEGA which is here 180 DEG. However, the spring 2 may include several pairs of arms taking advantage of the same geometries. The OMEGA angle of symmetry thus depends on the number of pairs of arms. The symmetries would then change to 120 DEG for three pairs, to 90 DEG for four pairs and 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.

Fig. 2a shows a sectional view of an arm of the spring 2 of FIG. 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 the other. 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 alpha angular offset between them. The two pairs of arms of the embodiment described here are arranged symmetrically with respect to the center C. The angle alpha is in this example 40 DEG, 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 alpha, 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 of 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 processing the 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 ranges, here three kinds of different ranges T1 or T2 or T3 and T4 and T5, which are each separated from one another by a separating space having an angle at the center epsilon. The length of a track is defined by the angle at the center phi. We also define the sum of the length of a track and the separating space as the gamma repetition angle, so gamma = phi + epsilon.

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

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 tracks T4 is phi 2, and of each of the third tracks is phi 3. phi 2 and phi 3 are here of the order of 20 DEG, therefore phi 2 = phi 3 <alpha. The areas T4 and T5 are spaced from each other by a distance epsilon 2, here of the order of 10 DEG. 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 impulse when the conductive arms 4, 6, 8, 10 come into frictional contact with the pads, as will be explained in more detail below. In the embodiment shown in FIG. 3, the third contact pads T5 are distributed alternately with respect to the contact pads T4.

As the arms are arranged symmetrically, in this example, at 180 DEG, the gamma repetition angle must be repeated an integer m of times in the OMEGA angle of symmetry, which here is 180 DEG. Thus, the following conditions are obtained:

if phi> / = alpha: m. gamma = OMEGA, and if phi <alpha: 2m. gamma = OMEGA,

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. Fig. 3 shows the example with OMEGA = 180 DEG and where m = 3, therefore where there are three tracks of the same contact on one half of the ring A, namely 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 tracks there are three T4 contacts, and for the third tracks 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:

for phi <alpha: alpha = n. gamma - phi = (n-1). phi + n. epsilon (1); for phi> / = alpha: alpha = m. (gamma / (m-1)) - phi, where m> 2 (2)

The parameter (n-1) corresponds to the number of contact pads between two arms, that is to say in the angle alpha. For condition (1), we understand that when this condition is met, the length of the electrical contact is extended to 2. phi, and for condition (2), the length of the electrical contact is extended to (alpha + phi). Thus, for the example given, in which 10 DEG corresponds to twenty minutes, as will be explained in more detail below, the length of the contact is 40 + 50 = 90 DEG. As this corresponds to three hours, the parameter m has the value "3". In fig. 3, we see that phi 1> alpha, and that phi 2 = phi 3 <alpha. For the example given, phi 1 must therefore fulfill condition (2), while phi 2 and phi 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. The 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 figs. 1 and 3, the tracks will be linked 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 DEG ). 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 the tracks T3 and T5 are thus linked together (fig. 4a). If the position of the analog display is advanced by one hour, tracks T1, T3 and T4 will be linked (fig. 4b). By advancing another hour, tracks T1 and T5 will be linked (fig. 4c), and after another hour, tracks T1, T2 and T4 will be linked together (fig. 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.

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 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 Vdd, therefore T5 = Vdd. However, as can be seen in fig. 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 Vdd. 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 Vdd, 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 as follows (always according to fig. 4 and 5): <tb> <TABLE> Columns = 10 <tb> Head Col 1: state no. <tb> Head Col 2: 1 <tb> Head Col 3: 2 <tb> Head Col 4: 3 <tb> Head Col 5: 4 <tb> Head Col 6: 5 <tb> Head Col 7: 6 <tb> Head Col 8: 7 <tb> Head Col 9: 8 <tb> Head Col 10: 9 <tb> <SEP> T1 + T2 + T3 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 5 <SEP> 5 <SEP> 5 <SEP> 4 <CEL AL = L> 4 <CEL AL = L> 4 <tb> <SEP> T4 + T5 <SEP> 1 <SEP> 3 <SEP> 2 <SEP> 2 <SEP> 3 <SEP> 1 <SEP> 1 <SEP> 3 <SEP> 2 <tb> </TABLE> <tb> <TABLE> Columns = 10 <tb> Head Col 1: state no. <tb> Head Col 2: 10 <tb> Head Col 3:11 <tb> Head Col 4:12 <tb> Head Col 5:13 <tb> Head Col 6:14 <tb> Head Col 7:15 <tb> Head Col 8:16 <tb> Head Col 9:17 <tb> Head Col 10:18 <tb> <SEP> T1 + T2 + T3 <SEP> 6 <SEP> 6 <SEP> 6 <SEP> 2 <SEP> 2 <SEP> 2 <SEP> 3 <CEL AL = L> 3 <CEL AL = L> 3 <tb> <SEP> T4 + T5 <SEP> 2 <SEP> 3 <SEP> 1 <SEP> 1 <SEP> 3 <SEP> 2 <SEP> 2 <SEP> 3 <SEP> 1 <tb> </TABLE>

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 memorized by the microprocessor P, states 8 or 10 can just be a very small movement of the hour hand of the analog display, see fig. 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 fig. 6b.

In fact, since the change of an hour corresponds in principle to three changes of states 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 of two with 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)

1. Synchronization device (D) for an electronic timepiece which comprises a time base, a train, an analog display driven by said train to display time information, and an electronic counter for storing some of said information, said device synchronization 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 OMEGA between each pair, the two arms of the same pair (4, 6; 8, 10) having an angular offset alpha, an electronic control device (P) connected to said circuit, the synchronization device (D) comprises said control device, - 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 phi, said pads being separated from one of the other of an angle at the center epsilon, and having a repetition angle gamma = phi + epsilon, the repetition angle gamma repeating an integer m of times in the angle of symmetry OMEGA when phi> / = alpha, and the gamma repetition angle repeating an integer 2 m times in the OMEGA symmetry angle when phi <alpha, and comprising m first distinct detection contact areas (T1, T2, T3) distributed regularly over the first half of said ring (A), and having a length phi 1 which is greater than or equal to said angle alpha, and m second (T4) and m third (T5) distinct contact pads distributed regularly and alternately over a second half of said ring (A) , every two xth range having a length phi 2 and each third range having a length phi 3, these lengths phi 2 and phi 3 being less than said angle alpha, in order to connect two ranges with said arms (4, 6, 8, 10). 2. Synchronization device (D) according to claim 1, characterized in that said contact wheel (1) is a twelve hour wheel making one revolution in twelve hours. 3. Synchronization device (D) according to claim 1, characterized in that said contact wheel (1) is a twenty-four hour wheel making one revolution in twenty-four hours. 4. Synchronization device (D) according to any one of the preceding claims, characterized in that the angular offset alpha between the two arms of the same pair (4, 6; 8, 10) is forty degrees. 5. 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 contact wheel (1). 6. 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 is located said hour wheel (1). 7. 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 operate in both detection ranges and supply ranges.