EP2790069B1 - Universal watch - Google Patents

Description

The present invention relates to a timepiece with universal time and provided with a date display mechanism.

In what follows, the term “local” is used for everything concerning the place where the user is located, for example in the expressions “local time” or “local time zone”. Similarly, the term “home” is used to designate anything relating to a user's home or reference location, such as in the expressions “home time” or “home time zone”. The home time zone is the time zone chosen as a reference (for example: Geneva).

There are many universal time timepieces, especially wristwatches and pocket watches. Swiss patents CH 690 205 and CH 693 191 each describe, for example, a timepiece whose central part of the dial comprises an hour hand and a minute hand as well as two movable discs surrounding said central part. The outer disc is inscribed with the names of the twenty-four cities each representing a time zone, while the inner disc has a graduation numbered from 1 to 24. The inner disc is kinematically connected to the hands of the time display and rotates at the right rate. one turn in twenty-four hours counterclockwise. So, CH 690 205 and CH 693 191 describe timepieces allowing easy and instantaneous reading of the time: all you have to do is look on the outer disc for the city whose time you want to know and then read the adjacent number on the inner disc.

In addition, the timepiece described in CH 693 191 also allows you to change the time zone. Thus, during a trip of the user for example, he can actuate a time zone mechanism making it possible to advance in steps of a 24th of a turn in an anti-clockwise direction the outer disc to bring the city ( time zone) desired at 12 o'clock in relation to the dial. This operation is easily carried out using a push-corrector located at 10 o'clock on the watch case. According to CH 693 191 , each press of the push-button simultaneously advances the inner disc in steps of one 24th of a turn counterclockwise and the hour hand one hour clockwise. The minute hand remains fixed.

Thus, if the user is not traveling, the outer city disc remains static, while the inner twenty-four hour disc, which is connected to the clock display, rotates counterclockwise in twenty-four hours. four hours. The combination of the outer city disc and the inner twenty-four hour disc allows the user to constantly read the time in the twenty-four most common time zones around the globe (see below for details on time zones and their distribution).

If the user changes time zone, it suffices for him to actuate the push-corrector by successive pressures to bring the city corresponding to his new time zone to midday relative to the dial. Each pressure on the push-button causes three simultaneous changes: the clockwise jump of one hour of the hour hand and the anti-clockwise advance of 1 / 24th of a turn of the outer and inner discs. Following a time zone correction, the time displayed by the timepiece corresponds to the time zone and therefore to the city displayed at 12 o'clock in relation to the dial on the outer disc.

In general, a timepiece with time zones or world time does not include a date display. Indeed, the date may be different from one time zone to another and a change of time zone could have to lead to a change of date.

In cases where the timepiece with time zones or world time furthermore includes a date display, it is generally not possible to display the local date automatically without manual correction by the user. So, for example, in a timepiece allowing the display of several time zones, the date is generally that of the home time zone (for example Geneva) and does not change with the time zone even if the user manually changes time zone.

The document EP 2 455 823 describes a timepiece allowing the display of several time zones and comprising a display of the date of the month in the selected time zone and a time zone correction mechanism (correction of the position of the city disc, the 24 hour disc , the 12 hour hand and the date disc) allowing you to change the time zone. This correction mechanism will cause the date to be displayed and automatically change the date (forward or backward) if the time zone correction occurs at the end of a day, regardless of whether this time zone correction results in the crossing of the line. change of date. Therefore, in some special cases in which the date should remain unchanged (see below), the date displayed by this timepiece after the time zone correction will be wrong and will not correspond to the time zone chosen by the user. .

The object of the present invention is to provide a timepiece with universal hours and allowing the display of time zones and comprising a date display mechanism, said date display displaying the date of the local time zone chosen by the user. In other words, the aim of the present invention is to provide a timepiece making it possible to display universal time and local time in a chosen time zone and the date corresponding to said time zone in a synchronized manner so that when the user changes time zone, the displayed date is automatically that of the chosen time zone and not that of a particular home time zone, without the user having to perform a manual correction of the date.

The present invention relates to a timepiece with universal hours according to claim 1. In particular, said timepiece is distinguished by the fact that it further comprises a synchronization mechanism kinematically connected to the date mechanism and to the time zone mechanism and making it possible to adjust automatically the date at each time zone correction and in particular when such a time zone correction results in a date change.

The purpose of a world time mechanism is to be able to simultaneously indicate the time in all other time zones. By convention, the terrestrial globe is divided into twenty-four time zones. The zone covered by a time zone, bounded by two meridians 15 ° apart, extends from the north pole to the south pole; it is centered on a meridian whose longitude is multiple of 15 °. The first time zone is centered on the Greenwich Mean Time and is generally referenced by the abbreviation UTC or UTC 0. When passing from one time zone to another, the time increases or decreases by one hour depending on whether the we move towards the east or towards the west, the minute and the second being in principle the same (except for a few exceptions where the shift is of the order of half an hour or quarter of an hour, but which will not be discussed here).

In general, countries tend to use a time zone in such a way that the average solar time in their territory is not too far from legal time (that is to say, for example, so that noon solar is not too far from legal noon). However, there are many exceptions to this principle: some countries crossed by several time zones have chosen a single legal time; some large countries are arbitrarily divided into several zones (Russia, Australia, etc.) which are sometimes offset from the original time zone; some countries have chosen a time that does not correspond to an entire offset with UTC (Greenwich), for example India with an offset of 5:30 compared to UTC; finally, some countries around the world apply a summer time and winter time system created to save energy. All these modifications compared to the initial system cause the time zones to lose their original shape, swollen in the middle, tapered at the ends, in favor of a division into zones. Thus, in total, all the countries of the globe currently use forty-three time zones or time zones, thirty-seven of which are used throughout the year.

In the following, only the twenty-four usual so-called “entire” time zones extending between UTC +12 and UTC -11 (in winter time) will be considered, UTC 0 designating the reference time zone of Greenwich . Each of these twenty-four “entire” time zones is associated with a city according to the following table. <i> Table 1: time zone and city correspondence </i> Time zone City Country UTC -11 Midway (atoll) UTC -10 Hawaii UTC -9 Anchorage UTC -8 Los Angeles UTC -7 Denver UTC -6 Mexico UTC -5 New York UTC -4 La Paz UTC -3 Rio UTC -2 South Georgia (island) UTC -1 Azores (archipelago) UTC 0 London UTC +1 Geneva UTC +2 Cairo UTC +3 Riyadh UTC +4 Moscow UTC +5 Karachi UTC +6 Dhaka UTC +7 Jakarta UTC +8 Hong Kong UTC +9 Tokyo UTC +10 Sydney UTC +11 Noumea UTC +12 Auckland

Obviously, the choice of cities representing each of the entire time zones is arbitrary. It is possible to choose another city corresponding to a given time zone, such as Paris for UTC +1 or San Francisco for UTC -8, instead of Geneva and Los Angeles respectively.

Considering the use of a reference meridian (Greenwich) for these time zones, there is also a meridian where, whatever the time, it is necessary when crossing it to add or subtract a day , depending on the direction of the crossing. This line can be considered to be located 12 hours ahead or 12 hours behind the Greenwich meridian depending on whether one travels the Earth respectively towards the east or towards the west. This line is called the “date change line”. It is an imaginary line on the surface of the Earth that runs approximately along the 180th meridian (east and west) in the Pacific Ocean. According to Table 1 above, the date change line is therefore crossed when the Auckland time zone changes to the Midway time zone. During the said passage between Auckland and Midway, it is therefore necessary to set the date back one day.

Thus, the date is also linked to the time zone and in addition to the date change which must be made every day at midnight, it is necessary to adjust the date to the time zone in which the user is located, in particular when changing from the date line.

In general, it is necessary to move the date forward or back by one day when crossing the date change line depending on the direction of the passage. However, there is a borderline case, between 11 p.m. and midnight in the time zone corresponding to Auckland where during the passage of the change line date (when switching to the time zone corresponding to Midway) the date must remain unchanged.

• Correction de la date par une action manuelle (sur actionnement manuelle de l'utilisateur, la date avance d'un jour, par exemple lorsqu'un mois ne comprend que 28, 29 ou 30 jours. Il s'agit d'une fonction conventionnelle d'un affichage de quantième);
• La date avance automatiquement d'un jour à minuit (là encore, il s'agit d'une fonction conventionnelle d'un affichage de quantième);
• La date recule d'un jour lors d'un changement de fuseau horaire entre Auckland et Midway, le changement ayant lieu avant 23h, heure d'Auckland (cas normal du passage de la ligne de changement de date);
• La date reste inchangée lors d'un changement de fuseau horaire entre Auckland et Midway, le changement ayant lieu entre 23h et minuit heure d'Auckland (cas limite du passage de la ligne de changement de date sans modification de la date).

Thus, it would be desirable to produce a timepiece with universal hours, allowing the setting to the local time during a change of time zones and comprising a date display mechanism which makes it possible to manage all of the following cases:

• Correction of the date by a manual action (on manual actuation by the user, the date advances by one day, for example when a month only includes 28, 29 or 30 days. This is a conventional function. a date display);
• The date automatically advances one day at midnight (again, this is a conventional function of a date display);
• The date is set back one day when there is a change of time zone between Auckland and Midway, the change taking place before 11 p.m. Auckland time (normal case of crossing the date change line);
• The date remains unchanged during a change of time zone between Auckland and Midway, the change taking place between 11 p.m. and midnight Auckland time (borderline case of crossing the date change line without modification of the date).

It can be seen that in order to produce such a timepiece, it is necessary to constantly know the time as well as the local time zone chosen by the user.

• La figure 1 est une vue de face d'une pièce d'horlogerie selon l'invention, le fuseau horaire étant Londres (UTC), l'heure locale étant 22h10 et le quantième affichant le 31.
• La figure 2 illustre le mécanisme permettant la synchronisation du quantième et du fuseau horaire dans la pièce d'horlogerie de la figure 1.
• La figure 3 est une vue en coupe du mécanisme de la figure 2.
• La figure 4 est une vue éclatée du mécanisme de la figure 2.
• Les figures 5 à 7 illustrent le changement automatique de la date à minuit, le fuseau horaire étant Londres, l'heure étant respectivement 23:30 le 31, minuit et 00:30 le 1 du mois suivant.
• Les figures 8 à 10 illustrent le passage de la ligne de changement de date avec le changement de fuseau horaire d'Auckland à Midway dans le cas normal:
  • La figure 8 illustre la pièce d'horlogerie de la figure 1 à 22h10, heure d'Auckland en date du 31.
  • La figure 9 illustre la pièce d'horlogerie de la figure 1 dans une position intermédiaire lors du passage du fuseau horaire d'Auckland au fuseau horaire de Midway.
  • La figure 10 illustre la pièce d'horlogerie de la figure 1 à 23h10, heure de Midway en date du 30, la date ayant reculé d'un jour pour tenir compte du passage de la ligne de changement de date.
• Les figures 11 à 13 illustrent le passage de la ligne de changement de date avec le changement de fuseau horaire de Auckland à Midway dans le cas limite:
• La figure 11 illustre la pièce d'horlogerie de la figure 1 à 23h30, heure d'Auckland en date du 31.
• La figure 12 illustre la pièce d'horlogerie de la figure 1 dans une position intermédiaire lors du passage du fuseau horaire d'Auckland au fuseau horaire de Midway.
• La figure 13 illustre la pièce d'horlogerie de la figure 1 à 00h30, heure de Midway en date du 31, la date étant restée inchangée.

The invention will now be described in detail with reference to the appended figures which illustrate by way of example one embodiment of a timepiece with universal hours according to the invention.

• The figure 1 is a front view of a timepiece according to the invention, the time zone being London (UTC), the local time being 10:10 p.m. and the date displaying the 31st.
• The figure 2 illustrates the mechanism allowing the synchronization of the date and the time zone in the timepiece of the figure 1 .
• The figure 3 is a sectional view of the mechanism of the figure 2 .
• The figure 4 is an exploded view of the mechanism of the figure 2 .
• The figures 5 to 7 show the automatic date change at midnight, the time zone being London, the time being 23:30 on the 31st, midnight and 00:30 on the 1st of the following month respectively.
• The figures 8 to 10 illustrate the passage of the date line with the change of time zone from Auckland to Midway in the normal case:
  • The figure 8 illustrates the timepiece of the figure 1 at 10:10 p.m. Auckland time on the 31st.
  • The figure 9 illustrates the timepiece of the figure 1 in an intermediate position when changing from the Auckland time zone to the Midway time zone.
  • The figure 10 illustrates the timepiece of the figure 1 at 11:10 p.m. Midway time on the 30th, the date having moved back one day to reflect the crossing of the date line.
• The figures 11 to 13 illustrate the passage of the date line with the change of time zone from Auckland to Midway in the borderline case:
• The figure 11 illustrates the timepiece of the figure 1 at 11:30 p.m. Auckland time on the 31st.
• The figure 12 illustrates the timepiece of the figure 1 in an intermediate position when changing from the Auckland time zone to the Midway time zone.
• The figure 13 illustrates the timepiece of the figure 1 at 12:30 a.m. Midway time on the 31st, the date remaining unchanged.

The timepiece according to the invention partially illustrated in the figures is a wristwatch with universal hours allowing the time to be set during a change of time zone and the display of the date. It conventionally comprises a watch case (not shown) and a winding stem 1. It also comprises a time display comprising in particular an hour hand 2 and a minute hand 3.

The timepiece includes a mechanism for displaying world times and time zones. Such a mechanism is known to those skilled in the art and may be similar to that described in CH 693 191 . In the illustrated embodiment, the mechanism for displaying world times and time zones comprises an outer disk 4 on which is affixed the name of twenty-four cities each corresponding to a time zone (according to Table 1 above ). This outer disc 4 is called city disc 4. A first inner disc 5, called the twenty-four hour disc 5, has a numbering from 1 to 24. The twenty-four hour disc 5 is kinematically linked to the hour wheel. of the time display mechanism of the timepiece so that it rotates continuously counterclockwise at the rate of one revolution in twenty-four hours. The twenty-four hour disc 5 and the hour hand 2 are therefore dependent so that it is impossible to shift them relative to each other.

The time displayed by the hour 2 and minute 3 hands corresponds to the city on the city disc 4 located at 12 o'clock in relation to the dial of the timepiece. On the figure 1 , the time displayed is local time for London and is 22 hours and 10 minutes. Reading the time in another time zone is immediate and does not require manipulation: to find out the time in Denver, just find the Denver inscription on the 4 cities disk and read the corresponding number on the twenty-four hour disc 5, in this case 15. Thus, in Denver, it is 15 hours and 10 minutes, the minute being assumed to be universal.

The mechanism for displaying world times and time zones still allows the user to change time zones and automatically display the time corresponding to this new time zone. In general, the timepiece comprises an actuating mechanism, such as a pusher, which can be actuated manually by the user the number of times necessary to bring the city corresponding to the new time zone and recorded on the city disk 4 at 12 o'clock in relation to the dial of the timepiece. Each actuation of the actuating mechanism causes the rotation of the city disc 4 and the twenty-four hour disc 5 by a 24th of a turn in the anti-clockwise direction and simultaneously the advance of one hour of the clock hand. hours 2. Such an actuation mechanism is well known to those skilled in the art and is described in detail for example in CH 693 191 . It may in particular include a pusher located at 10 o'clock relative to the case of the timepiece (symbolized by an arrow F ₁ in the figures) and actuating a double latch acting on the one hand on a toothing of the city disc 4 for the rotate anti-clockwise and on the other hand via a pawl carried by the rocker, on an hour correction wheel. The hour correction wheel drives on the one hand the twenty-four hour disc 5 and on the other hand the hour hand 2 by an angular value corresponding to one hour, one counterclockwise l 'other clockwise respectively.

The timepiece also includes a date display mechanism. Such a mechanism is well known to those skilled in the art and comprises a date indicator actuated once a day at the passage of midnight by the hour wheel of the timepiece by means of an appropriate gear train. In the illustrated embodiment, the date indicator has the form of a second internal disc, called date disc 6, bearing a numbering from 1 to 31 and cooperating with a date hand 7 pivoted at the center of the movement of the date. the timepiece. The date hand 7 can for example be driven at the passage of midnight by a date finger 8 which turns it. with a step. Said date finger 8 is itself integral with a date wheel 9 kinematically connected in a known manner to the hour wheel of the timepiece.

The date display mechanism further includes a manual date correction mechanism allowing the user to manually correct the date for months that have only 28, 29 or 30 days. For example, this correction mechanism can be actuated by means of a pusher or of the winding stem 1 so that the date hand 7 is pivoted by one step on each actuation of said pusher or on each revolution of the stem. winding mechanism 1. Such a correction mechanism is well known to those skilled in the art. Concerning the embodiment illustrated, it will be seen later that the mechanism for synchronizing the date to the time zone advantageously allows such a manual correction of the date.

When the user changes time zone by means of the time zone change button F ₁ provided for this purpose, he triggers the rotation of a 24th of a turn in the anti-clockwise direction of the city disc 4 and of the twenty disc. -4 hours 5 as well as the advancement of one hour of the hour hand 2 via the hour wheel of the timepiece. This rotation of the hour wheel of the timepiece also causes the rotation of the date wheel 9 and of the date finger 8. Thus, each change of time zone causes the rotation of one step of the date wheel 9. via the hour wheel.

In the embodiment illustrated, the time zone change button F ₁ actuates a double rocker which, on the one hand, drives the city disc 4 by a 24th turn in the anti-clockwise direction and which acts by means of '' a pawl on a twenty-four hour star which drives a time zone wheel pivoted in the center of the movement and in mesh with the hour wheel, thus driving the hour hand 2, the date wheel 9 and the date 8. An intermediate mobile 26 engaged with the date wheel 9 then rotates the twenty-four hour disc 5, the assembly being arranged so that the hour hand 2 advances by one hour and the twenty-four hour disc 5 pivots a 24th of a turn in the anti-clockwise direction. In the embodiment illustrated, it is therefore the date wheel 9 which drives the twenty-four-hour disc 5 in normal operation and during a manual time zone change by the user.

The timepiece according to the invention further comprises a mechanism for synchronizing the date with local time making it possible to synchronize the date to the time zone during a change of time zone and in particular during a change of zone. time leading to the passage of the date line.

The synchronization mechanism comprises a differential gear 10 pivoted at the center of the movement concentrically with the hour 2 and minute hands 3. The differential gear 10 comprises a central tube 11 pivoted on the plate 20 concentrically with the hand. The date hand 7 is driven out at one end of said central tube 11 on the dial side of the timepiece. The central tube 11 serves as a support for the other elements constituting the differential gear 10. A first sun wheel 12 is pivoted on the central tube 11. An input star 13 is mounted concentrically and integral with the first sun wheel 12. A wheel satellite carrier 14 is pivotally mounted on the central tube 11 above the assembly formed by the first sun wheel 12 and the input star 13. The satellite carrier wheel 14 carries a satellite mobile 15 comprising a first satellite 15a and a second satellite 15b rotated around the same axis on the planet wheel 14. The first satellite 15a is engaged with the first sun wheel 12 while the second satellite 15b is engaged with a second sun wheel, called a wheel output 16, driven on the central tube 11. A first jumper 17 pivoted on the planet wheel 14 cooperates with said output wheel 16 in order to guarantee the correct positioning of said wheel and thereby the stability of the needle. when ième 7 which is driven out on the central tube 11 and therefore integral with said output wheel 16. A second jumper 25 fixed to the plate 20 cooperates with the planet wheel 14 to guarantee its correct positioning. A third jumper 28 also fixed on the plate 20 cooperates for its part with the input star 13 to ensure its correct positioning.

The differential gear 10 is arranged so that, once a day, at the passing of midnight, the date finger 8 drives the input star 13 by one step in the clockwise direction.

The synchronization mechanism also comprises a date correcting lever 18 pivoted in A on the plate 20 of the movement of the timepiece. The movements of the date correcting latch 18 are limited by means of a screw foot 19 passing through a slot 21 made in the date correcting latch 18. The date correcting latch 18 comprises two arms 18a, 18b. At the end of its first arm 18a is articulated a correcting finger 22 intended to cooperate with the planet wheel 14 of the differential gear 10. The second arm 18b of the date correcting lever 18 carries a roller 23 intended to cooperate with a pin 24 carried by the cities disc 4 and positioned on said cities disc 4 near the Auckland marker to indicate the passage of the date change line, ie the passage between the Auckland and Midway time zones. Thus, the date correcting latch 18 is actuated by the pin 24 of the city disc 4 when the user changes from the Auckland time zone to that of Midway. The date corrective latch 18 remains stationary in all other cases.

• lorsque l'étoile d'entrée 13 pivote d'un pas dans le sens horaire entraînée par le doigt de quantième 8 et que la roue porte-satellite 14 reste immobile, la roue de sortie 16 pivote d'un pas dans le sens horaire;
• lorsque la roue porte-satellite 14 pivote d'un pas dans le sens horaire et que l'étoile d'entrée 13 reste immobile, la roue de sortie 16 pivote d'un pas dans le sens anti-horaire;
• lorsque la roue porte-satellite 14 pivote d'un pas dans le sens horaire et que l'étoile d'entrée 13 pivote d'un pas dans le sens horaire, alors la roue de sortie 16 reste immobile.

The differential gear 10 and in particular, the input star 13, the planet wheel 14 and the planet wheel 15 are shaped to operate as follows:

• when the input star 13 rotates one step clockwise driven by the date finger 8 and the planet wheel 14 remains stationary, the output wheel 16 rotates one step clockwise;
• when the planet wheel 14 rotates one step clockwise and the input star 13 remains stationary, the output wheel 16 rotates one step anti-clockwise;
• when the planet wheel 14 rotates one step clockwise and the input star 13 rotates one step clockwise, then the output wheel 16 remains stationary.

The operation of the date synchronization mechanism and in particular of the differential gear 10 during a change of date or time zone will now be described in detail with reference to figures 5 to 13 .

The first case described is that of the date change taking place every day at the passage of midnight, the user not effecting any change of time zone at this time.

This classic date change at the passage of midnight is illustrated in figures 5 to 7 . The selected time zone is London. In the figure 5 , the displayed time is 11:30 pm and the date hand 7 indicates the 31. In this position before midnight, the date finger 8 of the date display mechanism is not yet in contact with the input star 13 of the differential gear 10.

The figure 6 illustrates an intermediate position at midnight in which the date is changing. As midnight passes, the hour wheel of the timepiece drives the date wheel 9, which carries the date finger 8, by one step via an appropriate gear. This then engages the star of input 13 of the differential gear 10 and rotates it one step clockwise. In this general case, no time zone change occurs, the date correcting lever 18 therefore remains stationary and in particular does not drive, via its correction finger 22, the planet carrier wheel 14 which therefore remains stationary. The output wheel 16 of the differential gear 10 then rotates one step clockwise via the satellite mobile 15. Thus, the central tube 11 and the date hand 7 integral with the output wheel 16 also pivot. clockwise and the date hand 7 moves in the direction of mark 1 on the date disc 6. The figure 7 illustrates the situation at 12:30 am: the date has changed, date hand 7 now indicating 1 and date finger 8 is no longer engaged with input star 13 of the differential.

The figures 8 to 10 illustrate the operation of the date synchronization mechanism during the passage from the Auckland time zone to that of Midway and therefore during the passage of the date change line, said passage taking place between midnight and 11:00 p.m. Auckland time. In this case, the date must move back one day.

On the figure 8 , the time displayed is 10:10 p.m. Auckland time (at 12 o'clock on the dial) and the date hand 7 indicates 31. When the user actuates the time zone change button F ₁ to change the time zone, the city disc 4 is driven a 24th of a turn counterclockwise and Midway is brought to 12 o'clock on the dial. Simultaneously, the hour hand 2 advances by one hour driven by the hour wheel. Said hour wheel also drives the date wheel 9 and the date finger 8 by one step. The twenty-four hour disc 5 also pivots a 24th of a turn in the anti-clockwise direction driven in this form of a clock. execution by the date wheel 9 via an intermediate mobile 26. The pivoting of the city disc 4 brings the pin 24 into contact with the roller 23 of the date correcting lever 18. Under the action of said pin 24, the corrective lever of date 18 pivots in A and the correcting finger 22 actuates the planet wheel 14 by rotating it one step clockwise as illustrated in figure 9 (intermediate position).

In this situation, the input star 13 remains fixed since the date finger 8 is not engaged with said star 13 (midnight has not been crossed). Consequently, the planet wheel 14 drives the output wheel 16 by one step in the anti-clockwise direction via the satellite mobile 15. The date hand 7 carried by the central tube 11 integral with the output wheel 16 rotates counterclockwise and moves back one mark. Thus, as shown in figure 10 , after the crossing the date line, the time zone displayed at 12 o'clock on the dial is Midway, the time indicated by the hand is 11:10 p.m. and the date hand 7 indicates the 30th. The date has therefore been set back by one day when the date line is crossed.

The figures 11 to 13 illustrate the borderline case where the user changes time zone and crosses the date line when it is between 11:00 p.m. and midnight Auckland time. In this case, the date must remain unchanged.

On the figure 11 , the time displayed is 11:30 p.m. Auckland time and the date hand 7 displays the 31. When the user actuates the time zone change button F ₁ to change the time zone, the cities disc 4 is driven. a 24th turn counterclockwise and Midway is brought to 12 o'clock on the dial. Simultaneously, the hour hand 2 advances by one hour driven by the hour wheel. Said hour wheel also drives the date wheel 9 and the date finger 8 by one step. The twenty-four hour disc 5 also pivots a 24th of a turn in the anti-clockwise direction driven in this form of a clock. execution by the date wheel 9 via an intermediate mobile 26.

Now, as shown in figure 12 , in this particular case, by moving forward one hour, the hour hand 2 goes from 11 p.m. to midnight. Consequently, the date finger 8 comes into contact with the input star 13 and rotates the latter by one step in the clockwise direction (usual date change at midnight). Simultaneously, the pin 24 carried by the city disc 4 comes into contact with the roller 23 of the date correcting lever 18. Under the impetus of the pin 24, the date correcting lever 18 pivots at A and the correcting finger 22 makes rotate the planet wheel 14 clockwise by one step. However, the differential gear 10 is so designed that the simultaneous rotation of the input star 13 by one step clockwise and the planet carrier wheel 14 by one step clockwise leaves the star wheel stationary. output 16. Thus, in this limiting case, the date hand 7 integral with said output wheel 16 via the central tube 11 does not move and the date remains unchanged when the time zone changes.

• l'heure locale : l'étoile d'entrée 13 est pivotée d'un pas dans le sens horaire en cas de passage de minuit (et de correction manuelle de la date comme on le verra plus loin) et reste immobile dans tous les autres cas ;
• le passage de la ligne de changement de date : la roue porte-satellite 14 est pivotée d'un pas dans le sens horaire si un changement de fuseau horaire entraîne le passage de la ligne de changement de date.

The differential gear 10 therefore makes it possible to automatically synchronize the date according to the time zone chosen in all cases. Said differential gear 10 therefore takes two pieces of information as input:

• local time: the input star 13 is rotated one step clockwise when midnight has passed (and manual correction of the date as we will see below) and remains stationary in all the others case;
• the passage of the date change line: the planet wheel 14 is rotated one step clockwise if a change of time zone causes the passage of the date change line.

At the output of the differential gear 10 on the output wheel 16, depending on the combination of inputs, three choices are possible: the date goes back, the date advances or the date remains unchanged.

Those skilled in the art will be able to determine the appropriate gear ratios for the correct operation of the differential gear 10 described above. The gear ratios corresponding to the illustrated embodiment are detailed below by way of example.

• étoile d'entrée 13 à soixante-deux dents,
• première roue solaire 12 à trente et une dents,
• roue porte-satellite 14 à trente et une dents ;
• premier satellite 15a à dix dents,
• deuxième satellite 15b à vingt dents,
• roue de sortie 16 à trente et une dents.

In order to guarantee precise positioning of the date hand 7 for the 31 days of the month, the output wheel 16 preferably comprises thirty-one teeth. As mentioned above, the output wheel 16 has its own jumper 17 in order to ensure the stability of the date hand 7. The gear ratios of the other components of the differential gear 10 necessary for the correct operation of said gear. mechanism are easily calculable. In particular, in the embodiment illustrated, we have:

• entry star 13 to sixty-two teeth,
• first sun wheel 12 to thirty-one teeth,
• planet wheel 14 with thirty-one teeth;
• first satellite 15a with ten teeth,
• second satellite 15b with twenty teeth,
• output wheel 16 to thirty-one teeth.

Thus in the embodiment illustrated, if the input star 13 makes a 62nd turn clockwise and the planet wheel 14 remains stationary, the output wheel 16 makes a 31st turn in the clockwise (and therefore the date advances by one day). If the planet wheel 14 makes a 31st turn clockwise and the input star 13 remains stationary, then the output wheel 16 makes a 31st turn anti-clockwise (and therefore the date moves back). If input star 13 makes a 62nd turn clockwise and if planet wheel 14 makes a 31st turn clockwise, then output wheel 16 remains stationary (and the date does not change. ).

As indicated above, the timepiece according to the invention may also include a manual date correction mechanism for months comprising only 28, 29 or 30 days. The date correction mechanism can be directly connected to the differential gear 10 so that actuation by the user of said correction mechanism causes the clockwise rotation of the input star 13. This correction mechanism can for example be actuated by means of a date pusher (symbolized by an arrow F2 in the figures) placed on the watch case at 8 o'clock for example. Pressing said pusher actuates a second date correction rocker, the beak 27 of which cooperates with the input star 13 to cause the latter to advance one step in the clockwise direction. With this manual date correction mechanism, the user can, if he wishes, change the time zone and simultaneously manually correct the date without a conflict appearing, the differential gear 10 ensuring that, in all cases, the date displayed after the change of time zone is correct.

Thus, the timepiece according to the invention and in particular the differential gear 10 makes it possible to ensure all the functions expected of a date, namely automatic passage of the date at midnight and the possibility of manual correction of the date for the months in 28, 29 or 30 days. In addition, the timepiece according to the invention makes it possible to synchronize the date to the local time zone by managing both the standard case of the change of time zone leading to the advance of one hour and the particular case of the passage of the time zone. date change line which includes the general case where the date rolls back and the cutoff case where the date remains unchanged.

In addition, the differential gear 10 described above has the advantage of having come in the form of an additional independent mechanism and therefore easily adaptable to an existing movement displaying world times and time zones like that described in CH 693 191 .

The present embodiment has been described by way of example only. In particular, the time zone change buttons F ₁ and date change F ₂ could be replaced by any appropriate means making it possible to actuate the time zone mechanism and the manual date correction mechanism. An advantage of the present embodiment is to use only a single push-button for changing the time zone, the time and the corresponding date being set automatically.

In the present embodiment, each pressure on the time zone change button F ₁ causes the passage to a time zone more to the east of the previous one and the advance by one hour (the mechanism turns from west to west. East). It is of course obvious that the time zone mechanism could be arranged so that each pressure on the time zone change button F ₁ causes the passage to a time zone more to the west of the previous one and the retreat of one hour ( east and west rotation). In this case, the city disk and the the twenty-four hour disc then turns a 24th turn clockwise while the hour hand moves back, that is to say, takes one hour counterclockwise. Passing the date change line in this direction then involves moving the date forward by one day or leaving it unchanged as appropriate. This reversal is within the abilities of those skilled in the art and does not involve any complex modification with respect to the embodiment described. In particular, the differential mechanism of such a variant is in all respects similar to that described above.

The main characteristic of a timepiece according to the invention is that it allows the automatic synchronization of the date display with the universal hour and time zone change mechanism. This synchronization is carried out by means of a synchronization mechanism kinematically connected to the time zone correction mechanism and to the date mechanism that the timepiece comprises and making it possible to automatically adjust the date during a change of time zone by the user and in particular, when said change results in the passage of the date change line, and the date must be moved forward or back by one day or left unchanged as appropriate.

The timepiece according to the invention thus offers easy reading of world times, the possibility of changing the time zone as well as the display of the date automatically synchronized with the local time zone displayed even in borderline cases. The timepiece according to the invention therefore offers great comfort for the user, who is assured of reading the local time and date in all cases.

Claims (8)

1. Timepiece with global times, comprising:

   • a time display comprising an hours wheel, an hours hand (2) kinematically connected to the hours wheel and a minutes hand (3);

   • a mechanism for displaying global times and time zones which is arranged to allow setting when changing time zone, this mechanism comprising a rotating city disc (4), a twenty-four hour disc (5) kinematically connected to the hours wheel in order to be caused to rotate, one full rotation every twenty-four hours, and an actuating mechanism arranged to be manually actuated by the user and to cause, each time it is actuated, the rotation of the city disc (4) and the twenty-four hour disc (5) by one 24^th of a full rotation in a first direction and to pivot the hours hand (2) of the time display by one hour in a second direction opposite to the first direction,

   • a mechanism for displaying the date comprising a date indicator (6, 7) driven by a date going train (8, 9) kinematically connected to the hours wheel for driving same, and

   • a mechanism for synchronising the date arranged to synchronise the date to the time zone when changing time zone and kinematically connected to the mechanism for displaying the date and to the city disc (4),

   characterised in that the mechanism for synchronising the date is arranged:

   • to move the date indicator (6, 7) and to cause the date to fall back by one day when actuation of the actuation mechanism causes the passage from the time zone of Auckland to that of Midway and thus passage through the International Date Line, said actuation occurring between midnight and 23:00, Auckland time;

   • not to move the date indicator (6, 7) and to leave the date unchanged when actuation of the actuation mechanism causes the passage from the time zone of Auckland to that of Midway and thus passage through the International Date Line, said actuation occurring between 23:00 and midnight, Auckland time;

   such that the mechanism for synchronising the date allows the date to be automatically adjusted upon each change in time zone and in particular when such a change in time zone causes a change in date.
2. Timepiece as claimed in claim 1, characterised in that the mechanism for correcting the time zone kinematically connecting the city disc (4), the twenty-four hour disc (5) and the hours hand (2) of the time display is arranged so as to have the two discs (4, 5) effect one 24^th of a full rotation in the anti-clockwise direction and to advance the hours hand (2) by one hour in the clockwise direction upon each time zone correction.
3. Timepiece as claimed in claim 1 or 2, characterised in that the synchronisation mechanism comprises a differential gear (10).
4. Timepiece as claimed in claim 3, characterised in that the differential gear (10) comprises a first input mobile (12, 13) arranged to be driven by the date going train (8, 9) each day upon passing midnight, the differential gear (10) further comprising a second input mobile (14) arranged to be driven by the city disc (4) upon a time zone correction causing the passage through the International Date Line, a satellite mobile (15) pivoted on the second input mobile (14) and an output mobile (16) arranged to drive the date indicator (6, 7), the differential gear (10) being shaped such that the date indicator (6, 7) advances by one day when the first input mobile (12, 13) pivots by one step in the clockwise direction and the second input mobile (14) remains stationary, falls back by one day when the first input mobile (12, 13) remains stationary and the second input mobile (14) pivots by one step in the clockwise direction, and remains stationary when the first and second input mobiles (12, 13, 14) each simultaneously pivot by one step in the clockwise direction.
5. Timepiece as claimed in claim 4, characterised in that the synchronisation mechanism further comprises a lever (18) arranged to be pivoted by the city disc (4) upon a time zone correction causing the passage through the International Date Line, the lever (18) comprising a correcting finger (22) arranged to cooperate with the second input mobile (14) of the differential gear (10) for driving same.
6. Timepiece as claimed in any one of claims 4 or 5, characterised in that the first input mobile (12, 13), the second input mobile (14) and the output mobile (16) are concentric.
7. Timepiece as claimed in any one of claims 4 to 6, characterised in that the date indicator comprises a rotatable date hand (7) which cooperates with a date scale (6) borne by a dial of the timepiece, said date hand (7) being fixedly attached to the output mobile (16).
8. Timepiece as claimed in any one of claims 4 to 7, characterised in that the date mechanism further comprises a mechanism for manually correcting the date which can be manually actuated by a user to advance the date, said correction mechanism being arranged to drive the first input mobile (12, 13) of the differential gear (10) when manually changing the date.

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