CH707877A2 - Timepiece to universal time. - Google Patents

Abstract

The present invention relates to a timepiece of universal time comprising a switch for the time display comprising an hour hand (2) and a minute hand (3); a time zone mechanism for enabling time setting during a time zone change, this mechanism comprising a rotating city disk (4), a twenty-four hour disk (5) rotated at a rate of a turn in twenty-four hours, and a time zone correction mechanism kinematically connecting the city disc (4), the twenty-four hour disc (5) and the hour hand (2) of the referral to turn the two discs (4, 5) 24-hour counterclockwise and to advance the hour hand (2) by one hour at each time zone correction, and a mechanism date display device comprising a date indicator (6, 7) driven by a date wheel (8, 9). The timepiece further comprises a synchronization mechanism kinematically connected to the date mechanism and the time zone mechanism and for automatically adjusting the date at each time zone correction and in particular when such a time zone correction results. a date change.

Description

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

In what follows, the term "local" is used for everything related to the location where the user is, such as in the expressions "local time" or "local time zone". Similarly, the term "home" is used to refer to a user's place of residence or reference, such as "home time" or "home time zone". The home time zone is the time zone chosen as a reference (for example: Geneva).

[0003] There are many timepieces at universal times, especially wristwatches and pocket watches. The 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 and two movable discs surrounding said central portion. On the outer disk is inscribed the names of the twenty-four cities each representing a time zone, while the inner disk carries a graduation numbered from 1 to 24. The inner disk is kinematically connected to the hands of the time display and rotates right. one turn in twenty-four hours counterclockwise. Thus, CH 690 205 and CH 693 191 describe timepieces allowing an instant and easy reading of the time: it is sufficient to search on the outer disk for the city whose time is to be read and then read the adjacent figure on the inner disk.

In addition, the timepiece described in CH 693 191 also allows to change the time zone. Thus, during a journey of the user for example, it can actuate a time zone mechanism for advancing in steps of a <<turn> in the counterclockwise direction the outer disk to bring the city (time zone) desired at 12 o'clock in relation to the dial. This operation is easily done with a pusher-corrector located at 10 o'clock on the watch case. According to CH 693 191, each press of the push-button simultaneously moves the inner disk in steps of one turn in the anti-clockwise direction and the hour hand in one hour in the clockwise direction. The minute hand remains fixed.

Thus, if the user does not travel, the outer disk of the cities remains static, while the inner disk of twenty-four hours, which is connected to the time display, makes a turn in the counterclockwise direction. in twenty-four hours. The combination of the city's outer disk and the 24-hour inner disk allows the user to constantly read the time in the twenty-four most common time zones of the globe (see below for details on time zones and their distribution).

If the user changes time zone, it is sufficient to actuate the pusher-corrector by successive pressures to bring at noon compared to the dial the city corresponding to its new time zone. Each press of the pusher causes three simultaneous changes: the clockwise one-hour jump of the hour hand and the counter-clockwise 1/24 <a> turn of the outer and inner disks. . 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 relative to the dial on the outer disk.

In general, a timepiece timezone or universal time does not include date display. Indeed, the date can be different from one time zone to another and a change of time zone could have to cause a change of date.

In cases where the timepiece in time zones or universal time further comprises a date display, it is generally not possible to display the local date automatically without manual correction of the user. Thus, 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 changes manually time zone.

The object of the present invention is to produce a timepiece at universal times and for displaying the 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 object of the present invention is to produce a timepiece for displaying the world time and the local time in a chosen time zone and the date corresponding to said time zone synchronously so when the user changes the 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 needing to perform a manual correction of the date.

The present invention relates to a timepiece at universal times comprising: a switch for the time display comprising an hour hand and a minute hand; a mechanism of time zones to allow time setting during a time zone change, this mechanism comprising a rotating city disc, a twenty-four hour disc rotated at the rate of one turn in twenty-four hours. four hours, and a time zone correction mechanism kinematically connecting the disc of the cities, the twenty-four hour disc and the hour hand of the time switch so as to cause a 24 <è> <me> of turning the two discs anti-clockwise and advancing the hour hand by one hour at each time zone correction, and a date display mechanism including a date indicator driven by a date wheel. Said timepiece is distinguished by the fact that it further comprises a synchronization mechanism kinematically connected to the date mechanism and the time zone mechanism and for automatically adjusting the date at each time zone correction and in particular when such a time zone correction causes a date change.

The purpose of a universal time mechanism is to be able to simultaneously indicate the time in all other time zones. By convention, the globe is divided into twenty-four time zones. The zone covered by a spindle, 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 meridian and is generally referenced by the abbreviation UTC or UTC 0. When changing from one time zone to another, the time increases or decreases by one hour depending on whether we move east or west, the minute and the second being in principle the same (with some exceptions where the shift is of the order of half an hour or fifteen minutes, but which does not will not be processed here).

[0012] In general, countries tend to use a time zone such that the average solar time in their territory is not too far from the legal time (ie, for example, for that the solar noon is not too far from legal noon). There are, however, many exceptions to this principle: some countries crossed by several time zones have chosen only one legal time; some large countries are arbitrarily divided into several areas (Russia, Australia ...) that are sometimes out of step with the original time zone; some countries have chosen a time that does not correspond to an entire offset with UTC (Greenwich), such as India, with a 5:30 offset from UTC; finally, a part of the world's countries applies a system of summer time and winter time created to save energy. All these modifications compared to the initial system make the time zones lose their original form, swollen in the middle, tapered at the ends, in favor of a division by zones. Thus, in total, all the countries of the world currently use forty-three time zones or zones, including thirty-seven throughout the year.

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

It is obvious that 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, for example Paris for UTC +1 or San Francisco for UTC -8, instead of Geneva and Los Angeles respectively.

Given the use of a reference meridian (Greenwich) for these time zones, there is also a meridian where, regardless of the time, it is necessary when crossing to add or take away one day, depending on the direction of the crossing. This line may be considered to be 12 hours early or 12 hours behind the Greenwich meridian depending on whether the Earth is traveling east or west respectively. This line is called "date change line". It is an imaginary line on the surface of the Earth that runs along approximately the 180 th meridian (east and west) in the Pacific Ocean. According to Table 1 above, the date change line is crossed when switching from Auckland time zone to Midway time zone. During this passage between Auckland and Midway, it is necessary to move back the date of a day.

Thus, the date is also related to the time zone and in addition to the change of date to be made every day at midnight, it is necessary to adjust the date to the time zone in which the user is located, especially in case crossing the date change line.

In general, it is necessary to advance or move back the date of a day during the passage of date change line according to the direction of passage. However, there is a borderline case, between 11pm and midnight in the Auckland time zone where the date change line (at Midway time zone crossing) must have the date unchanged.

Thus, it would be desirable to make a timepiece at universal times, allowing the setting local time when changing time zones and including a date display mechanism that allows to manage all the time following cases: Correction of the date by a manual action (on manual activation of the user, the date advances by one day, for example when a month includes only 28, 29 or 30 days.This is a conventional function a date display); The date automatically advances from one day to midnight (again, it is a conventional function of a date display); The date moves back one day when changing time zones between Auckland and Midway, the change taking place before 23:00 Auckland time (normal case of the passage of the date change line); The date remains unchanged when changing time zones between Auckland and Midway, the change taking place between 23h and midnight Auckland time (case of crossing the date change line without changing the date).

It is noted that to achieve such a timepiece, it is necessary to always know the time and the local time zone chosen by the user.

The invention will now be described in detail with reference to the accompanying figures which illustrate by way of example an embodiment of a timepiece at universal times according to the invention. <tb> Fig. 1 <SEP> is a front view of a timepiece according to the invention, the time zone being London (UTC), the local time being 22:10 and the date showing the 31. <tb> Fig. 2 <SEP> illustrates the mechanism for synchronizing the date and the time zone in the timepiece of FIG. 1. <tb> Fig. 3 <SEP> is a sectional view of the mechanism of FIG. 2. <tb> Fig. 4 <SEP> is an exploded view of the mechanism of FIG. 2. <tb> Figs. 5 to 7 <SEP> illustrate the automatic change of the date at midnight, the time zone being London, the hour being respectively 23:30 on the 31st, midnight and 00:30 the 1st of the following month. <tb> Figs. 8 to 10 <SEP> illustrate the passage of the date change line with the change of time zone from Auckland to Midway in the normal case: <tb> Fig. 8 <SEP> illustrates the timepiece of FIG. 1 at 10:10 pm, Auckland time on the 31st. <tb> Fig. 9 <SEP> illustrates the timepiece of FIG. 1 in an intermediate position when switching from Auckland time zone to Midway time zone. <tb> Fig. 10 <SEP> illustrates the timepiece of FIG. 1 to 11:10 pm, Midway time on day 30, the date having declined by one day to reflect the passage of the date change line. <tb> Figs. 11 to 13 <SEP> illustrate the passage of the date change line with the time zone change from Auckland to Midway in the borderline case: <tb> Fig. 11 <SEP> illustrates the timepiece of FIG. 1 to 23:10, Auckland time on the 31st. <tb> Fig. 12 <SEP> illustrates the timepiece of FIG. 1 in an intermediate position when switching from Auckland time zone to Midway time zone. <tb> Fig. 13 <SEP> illustrates the timepiece of Figure 1 at 00:10, Midway time as of 31, the date remaining unchanged.

The timepiece according to the invention partially illustrated in the figures is a universal time wristwatch allowing the setting time on a time zone change and the display of the date. It comprises conventionally a watch case (not shown) and a winding stem 1. It also comprises a time display including a hour hand 2 and a minute hand 3.

The timepiece includes a mechanism for displaying universal times and time zones. Such a mechanism is known to those skilled in the art and may be similar to that described in CH 693191. In the illustrated embodiment, the mechanism for displaying universal times and time zones comprises an outer disk 4 on which is affixed the names of twenty-four cities each corresponding to a time zone (according to Table 1 above). This outer disk 4 is called the disk of the cities 4. A first inner disk 5, called a twenty-four hour disk 5, has a numbering from 1 to 24. The twenty-four hour disk 5 is kinematically connected to the hour wheel. the mechanism of the time display of the timepiece so that it rotates continuously in the opposite direction of clockwise to the rhythm of a turn in twenty-four hours. The twenty-four hours disk and the hour hand 2 are therefore dependent so that it is impossible to shift them relative to each other.

The hour displayed by the hands of the hours 2 and minutes 3 corresponds to the city of the disc cities 4 located at 12 o'clock relative to the dial of the timepiece. In fig. 1, the time shown 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 any manipulation: to know the time of Denver, it is enough to find the inscription Denver on the disc of the cities 4 and to read the corresponding figure on the Twenty-four hour disk 5, in this case 15. Thus, in Denver, it is 15 hours and 10 minutes, the minute being supposed universal.

The mechanism for displaying the universal times and time zones still allows the user to change the time zone and automatically display the time corresponding to this new time zone. In general, the timepiece comprises an actuating mechanism, such as a pushbutton, which can be manually operated by the user the number of times necessary to bring the city corresponding to the new time zone and recorded on the city disc 4 at 12h compared to the dial of the timepiece. Each actuation of the actuating mechanism causes the rotation of the disc of the cities 4 and the twenty-four hour disc 5 of a 24th turn in the anti-clockwise direction and simultaneously the one hour advance of the hour hand 2. Such an actuating mechanism is well known to those skilled in the art and is described in detail for example in CH 693 191. It may include a pusher located at 10 o'clock relative to the housing of the room d watchmaking (symbolized by an arrow F1sur the figures) and actuating a double rocker acting on one hand on a toothing of the disc of the cities 4 to rotate it anti-clockwise and secondly via a ratchet carried by the rocking, on an hour correction wheel. The hour correction wheel causes, on the one hand, the twenty-four hour disc 5 and, on the other hand, the hour hand 2 with an angular value corresponding to one hour, one counterclockwise the other clockwise respectively.

The timepiece also includes a date display mechanism. Such a mechanism is well known to those skilled in the art and includes a date indicator operated once a day at midnight passage by the hour wheel of the timepiece via a suitable wheel. In the illustrated embodiment, the date indicator is in the form of a second inner disk, called a date disk 6, bearing a numbering from 1 to 31 and cooperating with a date hand 7 pivoted at the center of the movement of the the timepiece. The date hand 7 may for example be driven midnight by a date finger 8 which rotates one step. Said date finger 8 is secured to a date wheel 9 kinematically connected in known manner to the hour wheel of the timepiece.

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

When the user changes the time zone by means of the time zone change button F1 provided for this purpose, it triggers the rotation of a 24 <i> turn in the anti-clockwise direction of the disk of the cities 4 and of the twenty-four hours disc 5 and the advance of one hour of the hour hand 2 via the hours wheel of the timepiece. This rotation of the hours wheel of the timepiece also causes the rotation of the date wheel 9 and the date finger 8. Thus, each time zone change causes the rotation of a step of the date wheel 9 via the hour wheel.

In the illustrated embodiment, the button for changing the time zone F1activates a double rocker which causes on the one hand the city disc 4 of a 24th turn in the counter-clockwise direction and which acts by means a ratchet on a twenty-four hour star that drives a timezone wheel rotated in the center of the movement and engaged with the hour wheel, thus driving the hour hand 2, the date wheel 9 and the finger 8. An intermediate wheel 26 engaged with the date wheel 9 then rotates the disc 24 hours, the assembly being arranged so that the hour hand 2 advance one hour and the disc of Twenty-four hours rotates by 24 <i> turn counter-clockwise. In the illustrated embodiment, it is therefore the date wheel 9 which drives the twenty-four hour disc 5 during normal operation and during a manual time zone change by the user.

The timepiece according to the invention further comprises a synchronization mechanism of the date at the local time to synchronize the date to the time zone during a time zone change and in particular during a time zone change. change of time zone causing the passage of the date change line.

The synchronization mechanism comprises a differential gear 10 pivoted in the center of the movement concentrically at the hands of the hours 2 and minutes 3. The differential gear 10 comprises a central tube 11 pivoted on the plate 20 concentrically to the switch. The date hand 7 is driven at one end of said central tube 11 on the dial side of the timepiece. The central tube 11 serves to support the other elements constituting the differential gearing 10. A first sun gear 12 is pivoted on the central tube 11. An input star 13 is concentrically mounted and integral with the first sun gear 12. A wheel satellite carrier 14 is pivotally mounted on the central tube 11 above the assembly formed by the first sun gear 12 and the star input 13. The planet wheel 14 carries a satellite mobile 15 comprising a first 15a satellite and a second satellite 15b pivoted about the same axis on the planet wheel 14. The first satellite 15a is engaged with the first sun gear 12 while the second satellite 15b is engaged with a second sun wheel, said 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 to ensure the proper positioning of said wheel and thereby the s tability of the date hand 7 which is driven on the central tube 11 and thus secured to said output wheel 16. A second jumper 25 fixed on the plate 20 cooperates with the planet wheel 14 to ensure its proper positioning. A third jumper 28 also fixed on the plate 20 cooperates meanwhile with the star input 13 to ensure its proper positioning.

The differential gear 10 is arranged so that once a day, at midnight, the date finger 8 causes the star input 13 of a step clockwise.

The synchronization mechanism further comprises a date correction lever 18 pivoted at A on the plate 20 of the movement of the timepiece. The movements of the date correction lever 18 are limited by means of a screwthread 19 passing through a slot 21 made in the date correction lever 18. The date correction lever 18 comprises two arms 18a, 18b. At the end of its first arm 18a is articulated a correction finger 22 intended to cooperate with the planet wheel 14 of the differential gearing 10. The second arm 18b of the date correction lever 18 carries a roller 23 intended to cooperate with a pin 24 carried by the disk of the cities 4 and positioned on said disk of the cities 4 near the Auckland landmark to indicate the passage of the line of change of date, the passage between the time zones of Auckland and Midway. Thus, the date correction flip-flop 18 is operated by the pin 24 of the city disc 4 when the user moves from the Auckland time zone to the Midway time zone. The date correction lever 18 remains stationary in all other cases.

The differential gear 10 and in particular the input star 13, the planet carrier wheel 14 and the satellite mobile 15 are shaped to function as follows: when the input star 13 rotates one step in the clockwise direction 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 pivots one pitch counterclockwise and the star input 13 remains stationary, the output wheel 16 rotates one step counterclockwise; when the planet wheel 14 pivots counterclockwise 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 FIGS. 5 to 13.

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

This change of date at the midnight crossing is illustrated in FIGS. 5 to 7 . The selected time zone is London. In FIG. 5, the time displayed is 23:30 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 date. input star 13 of the differential gear 10.

FIG. 6 illustrates an intermediate position at midnight in which the date is changing. At the passage of midnight, the hour wheel of the timepiece drives with a step via a suitable gear the date wheel 9 which carries the date finger 8. It then comes into engagement with the star of input 13 of the differential gear 10 and rotates one step clockwise. In this general case, no time zone change occurs, the date correction lever 18 therefore remains motionless and in particular does not cause via its correcting finger 22 the planet carrier wheel 14 which therefore remains motionless. 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. in the clockwise direction and the date hand 7 moves towards the marker 1 on the date disc 6. FIG. 7 illustrates the situation at 00:30: the date has changed, the date hand 7 now indicating the 1 and the date finger 8 is no longer in contact with the input star 13 of the differential.

Figs. 8 to 10 illustrate the operation of the date synchronization mechanism during the passage of the time zone from Auckland to that of Midway and therefore during the passage of the date change line, said passage being between midnight and 23:00 pm Auckland. In this case, the date must go back one day.

In FIG. 8, the time displayed is 22:10 Auckland time (at 12 o'clock on the dial) and the date hand 7 indicates the 31. When the user actuates the time zone change button to change the time zone, the disc 4 cities is driven a 24 <i> turn in the counterclockwise direction and Midway is brought to 12 o'clock on the dial. At the same time, the hour hand 2 advances one hour driven by the hour wheel. Said hour wheel also causes the date wheel 9 and the date finger 8 to step one step. The twenty-four hour disc 5 also pivots with a 24th turn in the anti-clockwise direction entrained in this wheel. embodiment of the date wheel 9 via an intermediate mobile 26. The pivoting of the disc of the cities 4 brings the pin 24 in contact with the roller 23 of the correction scale of date 18. Under the action of said pin 24, the The date correction lever 18 pivots at A and the correcting finger 22 actuates the planet wheel 14 by rotating it one step in the counterclockwise direction as illustrated in FIG. 9 (intermediate position).

In this situation, the star input 13 remains fixed since the date finger 8 is not engaged with said star 13 (midnight has not been crossed). As a result, the planet carrier wheel 14 drives the output wheel 16 one step anti-clockwise 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 illustrated in FIG. 10, after the passage of the date change line, the time zone displayed at 12 o'clock on the dial is Midway, the time indicated by the switch is 23:10 and the date hand 7 indicates the 30. The date has far back one day when passing the date change line.

Figs. 11 to 13 illustrate the borderline case where the user changes their time zone and passes the date change line while it is between 23:00 and midnight Auckland time. In this case, the date must remain unchanged.

In FIG. 11, the time displayed is 23:30 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 disc of the cities 4 is driven by a 24th turn in the counterclockwise direction and Midway is brought at 12 o'clock on the dial. At the same time, the hour hand 2 advances one hour driven by the hour wheel. Said hour wheel also causes the date wheel 9 and the calendar finger 8 to step by one step. The twenty-four hour disc 5 is also rotated by a 24th turn in the counterclockwise direction driven in this form. execution by the date wheel 9 via an intermediate mobile 26.

However, as shown in FIG. 12, in this particular case, advancing by one hour, the hour hand 2 passes from 23h to midnight. Consequently, the date finger 8 comes into contact with the input star 13 and rotates it one step in the clockwise direction (usual date change at midnight). Simultaneously, the pin 24 carried by the disk of the cities 4 comes into contact with the roller 23 of the date correction lever 18. Under the pulse of the pin 24, the date correction lever 18 pivots at A and the correction finger 22 makes rotate the planet wheel 14 in a counter-clockwise direction. However, the differential gearing 10 is so designed that the simultaneous rotation of the input star 13 by one clockwise pitch and the planet gear wheel 14 by one counterclockwise pitch still leaves the wheel output 16. Thus, in this limit case, the date hand 7 secured to said output wheel 16 via the central tube 11 does not move and the date remains unchanged at the time zone change.

The differential gear 10 thus automatically synchronizes the date according to the time zone chosen in all cases. Said differential gear 10 thus takes two input information: the local time: the star of entry 13 is rotated of a step in the clockwise direction in case of passage of midnight (and manual correction of the date as one will see it further) and remains immobile in all the others case; the passage of the date change line: the planet wheel 14 is rotated by a step counterclockwise if a change in 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 backs, the date ahead or the date remains unchanged.

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

To ensure accurate positioning of the date hand 7 for the 31 days of the month, the output wheel 16 preferably includes thirty-one teeth. As mentioned above, the output wheel 16 has its own jumper 17 to ensure the stability of the date hand 7. The gear ratios of the other components of the differential gear 10 necessary for the proper functioning of said mechanism are easily calculable. In particular, in the illustrated embodiment, there is: input star 13 to sixty-two teeth, first solar wheel 12 to thirty-one teeth, satellite carrier wheel 14 to thirty-one teeth; first satellite 15a with ten teeth, second satellite 15b with twenty teeth, exit wheel 16 to thirty-one teeth.

Thus, in the illustrated embodiment, if the input star 13 is a 62 rpm clockwise and the planet wheel 14 remains stationary, the output wheel 16 is 31 <th> turn clockwise (and so the date advances by one day). If the planet-carrier wheel 14 is 31 <i> turn clockwise and the entry star 13 remains stationary, then the exit wheel 16 turns 31 <i> turn in the anti-clockwise direction. hour (and thus the date moves back). If the input star 13 makes a clockwise turn of 62 and the planet wheel 14 turns 31 clockwise, then the output wheel 16 remains stationary ( and the date does not change).

As indicated above, the timepiece according to the invention may further comprise a manual correction mechanism of the calendar for months comprising only 28, 29 or 30 days. The date correction mechanism can be directly connected to the differential gear 10 so that the user actuation of said correction mechanism causes the clockwise rotation of the input star 13. This correction mechanism can for example be operated 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 on said pushbutton actuates a second date correction flip-flop whose spout 27 cooperates with the input star 13 to advance it one step in the clockwise direction. With this mechanism of manual correction of the date, the user can if he wishes to change the time zone and simultaneously manually correct the date without a conflict appears, the differential gearing 10 ensuring that, in any case, the date displayed after the time zone change is correct.

Thus, the timepiece according to the invention and in particular the differential gear 10 makes it possible to provide all the functions expected of a date, namely automatic date change at midnight and possibility of manual correction of the date for 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 causing the advance of one hour and the particular case of the passage of the time zone. a date change line that includes the general case where the date goes back and the limit case in which the date remains unchanged.

In addition, the differential gear 10 described above has the advantage of being in the form of an independent additional mechanism and therefore easily adaptable to an existing movement displaying the universal times and time zones such as described in CH 693191.

The present embodiment has been described by way of example only. In particular, the time zone change buttons F1 and date change F2 could be replaced by any appropriate means for operating the time zone mechanism and the manual date correction mechanism. An advantage of the present embodiment is to use only one pushbutton for the change of time zone, setting the time and the corresponding date is done automatically.

In the present embodiment, each press on the time zone change button F1 causes the passage to a time zone further east of the previous one and the advance of one hour (the mechanism turns from west). is). Of course, it is obvious that the time zone mechanism could be arranged so that each press on the time zone change button F1 leads to the passage to a time zone further west of the previous one and the one hour recoil (rotation of the time zone). 'East and West). In this case, the city disc and the twenty-four hours disc then turn 24 ème clockwise while the hour hand moves backwards, that is, takes a step of one hour counter-clockwise. The passage of the date change line in this direction then implies to advance the date of a day or to leave it unchanged as the case may be. This inversion is within the abilities of those skilled in the art and does not entail 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 to allow the automatic synchronization of the date display with the mechanism of universal hours and time zone change. This synchronization is performed by means of a synchronization mechanism kinematically connected to the time zone correction mechanism and the date mechanism that includes the timepiece and for automatically adjusting the date during a time zone change by the user and in particular, when said change entails the passage of the date change line, and that it is necessary to advance or retreat the date of a day or leave it unchanged as the case may be.

The timepiece according to the invention thus offers an easy reading of the universal times, the possibility of changing the time zone and the display of the synchronized date automatically to the local time zone displayed even in the limit 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 at universal times comprising: - a switch for the time display comprising an hour hand (2) and a minute hand (3); A mechanism of time zones for enabling time-setting during a time zone change, this mechanism comprising a rotating city disc (4), a twenty-four hour disc (5) driven in rotation with a turn in twenty-four hours, and a time zone correction mechanism kinematically connecting the city disc (4), the twenty-four hour disc (5) and the hour hand (2) of the time-shifting so as to make a 24 th turn in a first direction to both disks (4, 5) and to rotate the hour hand (2) by one hour in a second direction opposite the first one to each time zone correction, and - A date display mechanism comprising a date indicator (6, 7) driven by a date wheel (8, 9), characterized in that it further comprises a synchronization mechanism kinematically connected to the date mechanism and the time zone mechanism and making it possible to automatically adjust the date at each time zone correction and in particular when such a spindle correction time changes the date. 2. Timepiece according to claim 1, characterized in that the time zone correction mechanism kinematically connecting the city disc (4), the twenty-four hour disc (5) and the hour hand ( 2) of the time switch is arranged to turn the two discs (4, 5) counterclockwise 24 <i> and to advance the hour hand (2) by hour clockwise at each time zone correction. 3. Timepiece according to claim 1 or 2, characterized in that the synchronization mechanism comprises a differential gear (10). 4. Timepiece according to claim 3, characterized in that the differential gear (10) comprises a first input mobile (12, 13) arranged to be driven by the date wheel (8, 9) each day at the passage of midnight, a second mobile input (14) arranged to be driven by the disk cities (4) during a time zone correction causing the passage of the date change line, a satellite mobile (15) pivoted on the second movable input (14) and an output movable (16) arranged to drive the date indicator (6, 7), the differential gear (10) being shaped so that the date indicator (6, 7) advances by one day when the first input mobile (12, 13) rotates one step clockwise and the second input mobile (14) remains stationary, moves back by one day when the first input mobile (12, 13) remains stationary and the second input mobile (14) rotates one step counter-clockwise and remains stationary when the first and second input mobiles (12, 13, 14) are simultaneously pivoted one step clockwise and one step apart respectively. counter clockwise. 5. Timepiece according to claim 4, characterized in that the synchronization mechanism further comprises a rocker (18) arranged to be pivoted by the disc cities (4) during a time zone correction causing the passage of the date change line, the rocker (18) comprising a correction finger (22) arranged to cooperate with the second mobile input (14) of the differential gear (10) for the drive thereof . 6. Timepiece according to one of claims 4 or 5, characterized in that the first mobile input (12,13), the second mobile input (14) and the mobile output (16) are concentric. 7. Timepiece according to one of claims 3 to 6, characterized in that the date indicator comprises a date hand (7) rotatable and cooperating with a date scale (6) carried by a dial of the timepiece, said date hand (7) being integral with the output mobile (16). 8. Timepiece according to one of claims 4 to 7, characterized in that the date mechanism further comprises a manual date correction mechanism manually operable by a user to advance the date, said correction mechanism being arranged to drive the first input gear (12, 13) of the differential gear (10) during a manual date correction.