HK1257134B - Timepiece comprising a day/night display that takes account of seasonal variations - Google Patents

Description

Timepiece comprising day/night display means taking into account seasonal variations

Technical Field

The invention relates to a timepiece comprising a timepiece movement and a sunrise and sunset indicating device taking into account seasonal variations, the sunrise and sunset indicating device comprising a ball representing the earth, a support and a ring mounted on the support and arranged concentrically with the ball, the ring being arranged to indicate the position of the earth's boundary line, and the ring and the ball being arranged so as to be able to pivot relative to each other about a first axis corresponding to the polar axis of the earth at a rate of one revolution per 24 hours and to pivot relative to each other about a second axis intersecting the first axis perpendicularly at the centre of the ball, the ring being mounted so as to pivot on the support about the second axis, the sunrise and sunset indicating device further comprising an annual cam having a profile representing the inclination of the sun with respect to the equatorial plane and being arranged to be driven in rotation at a rate of one revolution per year, the cam follower is arranged to cooperate with the annual cam, and the kinematic chain is arranged to connect the cam follower with the ring so that the plane contained by the ring forms an angle with the first axis equal to the angle of the relative inclination of the sun with respect to the equatorial plane.

Background

The duration of the daytime is the time between the time when the upper edge of the sun appears above the horizon in the east at sunrise to the time when the upper edge of the sun disappears below the horizon in the west at sunset every day. Whenever there is half of the earth's surface that is illuminated by the sun and the other half that is in the dark. A boundary between the earth's dark and illuminated parts of the earth is the boundary between the illuminated parts of the earth and the parts of the earth that are in the dark. Geometrically, the earth's boundary of light and dark is a great circle around the earth. The great circle extends in a plane perpendicular to the orbital plane of the earth around the sun (called the ecliptic plane). It is also noted that the center of the earth is at the intersection of these two planes.

Generally, the duration of daylight varies throughout the year and also depends on latitude. The variation is due to the inclination of the rotation axis of the earth rotating about itself with respect to the ecliptic plane. The inclination corresponds by definition to the latitude of the regression line, i.e. + -. 23 deg. 27'. As is generally known, the duration of daylight is shortest in the winter solstice of the northern hemisphere and shortest in the summer solstice of the southern hemisphere. At the circadian half-point, the duration of the day and night is equal anywhere on the earth.

There are already known timepieces arranged to indicate the current position of the dividing line between day and night and satisfying the definition given in the preamble above. In particular, european patent documents EP2911013, EP2977832 and EP3007012 in the name of the applicant are described. However, the use and design of these timepieces presents a certain number of difficulties.

In particular, the hoop and the earth are arranged to be driven by the movement to rotate relative to each other at a rate of one revolution per 24 hours, thereby providing an indication of the current position of the earth's boundary on the earth's surface. In this regard, it will be understood that the hour wheel of a timepiece can advantageously be used as a driving element for this rotation, since it usually completes one revolution every 12 hours. This requires only to compare the hour wheel with, for example, a wheel having a ratio equal to 1: 2. However, one problem with this configuration is that when the hands of the timepiece are acted to switch from summer to winter, for example, the indication of the current position of the earth's light and dark boundary on the earth moves, although this does not reflect the actual movement of the sun in the sky.

Disclosure of Invention

It is an object of the present invention to overcome the above-mentioned drawbacks of the prior art. The invention achieves this object by providing a timepiece movement according to the appended claim 1.

According to the invention, the timepiece movement includes a manually actuatable time varying mechanism arranged to pivot the hour wheel set step-wise independently of the motion work. It will be appreciated by those skilled in the art that one advantage of this correction mechanism is that it makes it possible to change the time zone or switch between summer and winter time without affecting the watch's indication of minutes and seconds.

According to the invention, the timepiece movement also comprises, on the one hand, a second kinematic chain connecting the time wheel set with the ring or with the ball in order to drive the ring or ball so as to rotate one with respect to the other at a rate of one revolution per 24 hours, and on the other hand, a disengagement mechanism arranged to disengage the second kinematic chain when the time-varying mechanism is implemented to pivot the time wheel set to change from summer time to winter time or vice versa. One advantage of this arrangement is that the rotation of the rings or spheres relative to each other at a rate of one revolution per 24 hours is not affected by any daylight/winter time corrections.

Furthermore, according to the invention, the timepiece comprises a calendar mechanism comprising date display means for displaying the date arranged to be driven by the hour wheel set and month display means arranged to be driven by the date display means. Furthermore, the year cam is arranged to be driven by the date display device. One advantage of this design is that the year cam can automatically return to the correct position without any possible error, simply by resetting the date of the calendar mechanism, after the timepiece has stopped for an indefinite period of time.

According to the invention, the date display device is driven by an hour wheel set. Under these conditions, the hour correction automatically causes a correction of the calendar mechanism when the wearer of the timepiece pivots the hour wheel set step-wise forward or backward by means of the time-varying mechanism.

According to one advantageous variant of the invention, the timepiece movement comprises a first hour wheel, called "hour wheel", meshing with the motion work and forming part of a pair of hour wheels, and a second hour wheel, called "hour wheel". Furthermore, the time-varying mechanism comprises a coupling and positioning device which is disengageable and arranged to selectively disengage the first and second hour wheels and to rotate them integrally.

Drawings

Other characteristics and advantages of the invention will become apparent from the following description, given by way of non-limiting example only, with reference to the accompanying drawings, in which:

fig. 1 is a block diagram schematically illustrating the kinematic connections between the different mechanisms of a timepiece according to a first particular embodiment of the invention;

fig. 2 is a block diagram schematically illustrating the kinematic connections between the different mechanisms of a timepiece according to a second particular embodiment of the invention;

fig. 3A and 3B are a cross-sectional view and a view, respectively, of an exemplary mechanism thus known, comprising a first hour wheel and a second hour wheel and a disengageable coupling device arranged to rotate and position the two hour wheels in one piece, or to disengage the two hour wheels.

Detailed Description

The attached fig. 1 is a block diagram showing kinematic connections associating different mechanisms of a timepiece according to a first exemplary embodiment of the invention. The schematic diagram of this particular base shows, by means of thick arrows, the means for transmitting the driving force provided by the movement to the various mechanisms and, by means of thin arrows, the kinematic link arranged to transmit the commands manually input by the user.

In the schematic representation of fig. 1, the arrows symbolize kinematic connections which connect the symbols representing the different mechanisms of the timepiece between them. The mechanism denoted by the symbol is a drive mechanism 103 combining a drive member, a speed regulation member and an escapement, a minute wheel set (reference numeral 105) integral with the minute display member and arranged to be driven by the drive mechanism at a rate of one revolution per hour, an hour wheel set 107 rotating integrally with the hour display member, a motion work 106 connecting the minute wheel set with the hour wheel set so that the hour wheel set is driven at a rate of one revolution per 12 hours, a time change mechanism (reference numeral 101) interposed between the motion work 106 and the hour wheel set 107. In the illustrated example, the hour wheel set is arranged to rotate one full turn every 12 hours. However, it will be appreciated that according to the invention, the hour wheel set may alternatively be arranged to rotate at a rate of one revolution per 24 hours.

Still referring to fig. 1, it can be seen that the timepiece illustrated also comprises a calendar mechanism 121, which calendar mechanism 121 comprises in particular a date display 123 for displaying the date arranged to be driven via the time wheel set 107 and a month display 125 arranged to be driven by the date display via a monthly drive (reference 127 in fig. 1). According to a first embodiment constituting the subject of the invention, the date display 123 comprises a date wheel (not shown) and the monthly drive 127 is arranged to increment the month display 125 by one each time the date wheel passes from a position corresponding to the last day of the month to a position corresponding to the first day of the next month. The calendar mechanism 121 of the present specification is preferably a perpetual calendar mechanism or an annual calendar mechanism. It should be recalled that, as is well known to those skilled in the art, a perpetual calendar mechanism is one that automatically takes into account the different durations of the months and leap years, unlike a perpetual calendar, which does not take into account the 2-month or leap years considered as 30-day months. Therefore, the annual calendar mechanism must be manually corrected once per year at the end of 2 months. Since perpetual calendar mechanisms and calendar mechanisms are well known to those skilled in the art, the operation of the calendar mechanism 121 will not be described in detail. This further illustrates that the invention is not limited to timepieces comprising a perpetual calendar mechanism or an annual calendar mechanism. The calendar mechanism may also be of a different type.

According to the invention, the illustrated timepiece also comprises a sunrise and sunset indicating device for indicating sunrise and sunset taking into account seasonal variations. These devices comprise a sphere representing the earth, a support and a ring mounted on the support concentrically with the sphere and arranged to indicate the position of the earth's bright-dark boundary. The ring and the ball are arranged to be driven to rotate relative to each other at a rate of one revolution per 24 hours about a first axis corresponding to the polar axis of the earth. Furthermore, the ring is mounted on the support so as to be able to pivot relative to the ball also about a second axis which intersects the first axis perpendicularly at the centre of the ball. The sunrise and sunset indicating device further comprises an annual cam having a profile representative of the relative inclination of the sun with respect to the equatorial plane and arranged to be driven in rotation at a rate of one revolution per year, a cam follower arranged to cooperate with the annual cam, and a first kinematic chain arranged to connect the cam follower with the annular ring so that the plane contained by the annular ring forms an angle with the first axis equal to the inclination angle of the sun with respect to the equatorial plane. Referring to fig. 1, it can be seen that in the embodiment shown, the timepiece comprises a sunrise and/or sunset indicating mechanism comprising a sphere 117 representing the earth and a hemispherical case 113 arranged concentrically with the sphere 117 so as to darken or hide half of the earth. The housing 113 has a substantially circular edge 113a and it will be appreciated that this edge forms the said collar of the sunrise and sunset indicator device according to the invention. Still referring to fig. 1, it can also be seen that the year cam is designated 111 and forms part of a recliner mechanism (generally designated 109). It should also be understood that a cam follower (not shown) also forms part of the recliner mechanism.

According to the invention, the date display means 123 are arranged to drive the year cam 111 via the third kinematic chain 118. As already mentioned, the date display device 123 of the present example comprises a date wheel (not shown), and the third kinematic chain 118 adopts a chain arranged downstream of the date wheel and having a speed of 1: 12 in the form of a reduction gear train. In this case, the reduction gear train comprises a 16-tooth pinion integral with the date wheel, a 48-tooth gear meshing with this 16-tooth pinion and integral with a 14-tooth intermediate pinion, which in turn meshes with a 56-tooth gear integral with the year cam 111 (the various gears and pinions are not shown in fig. 1). The year cam is thus arranged to rotate one revolution when the date wheel rotates 12 revolutions. Therefore, it should be understood that the year cam 111 and the calendar mechanism 121 are arranged to advance in synchronization.

According to the embodiment of the invention shown in fig. 1, the movement of the hemispherical shell 113 relative to the sphere 117 is the result of a combination of different rotations about two perpendicular axes intersecting at the center of the sphere. The first of these two rotations is performed by the ball 117, the ball 117 being arranged to rotate about the first of these two axes at a rate of one revolution per 24 hours, and the other rotation corresponding to the pivoting of the hemispherical shell 113 representing the darkness (dark hemisphere) about the second axis and occurring as a function of the inclination angle of the hemisphere with respect to the first axis. Sunrise and/or sunset indication mechanism 115 is shown twice in fig. 1, as the movement of dark hemisphere 113 and sphere 117 relative to each other is two functionally independent movements. With reference to this figure, it will be understood that the mechanism 115 is shown for the first time to depict the rotation of the sphere 117 about the first axis at a rate of one revolution per 24 hours, and for the second time to depict the pivoting of the dark hemisphere 113 about the second axis.

According to the invention, the pivoting movement about the second axis is controlled using a year cam 111, the profile of the year cam 111 representing the inclination of the sun above or below the equatorial plane. A cam follower (not shown) is arranged to transmit the change in cam profile to the hemispherical shell 113 via the first kinematic chain 112. According to a first embodiment of the invention, the dark hemisphere 113 is mounted to pivot on a fixed support and, like the arrangement of the first kinematic chain 112, the arrangement of the indicating means 115 may, for example, comply with the description given in european patent document EP 2911013. This document is incorporated by reference into the present specification.

According to an embodiment of the invention, time wheel set 107 is connected to ball 117 by a kinematic chain 120 (hereinafter "second kinematic chain 120"). The second kinematic chain is arranged to drive the sphere in rotation so that it rotates at a speed of one revolution per 24 hours about a first axis corresponding to the polar axis of the earth. Fig. 1 also shows a disengagement mechanism 133 arranged to disengage the second kinematic chain 120 on command.

Referring again to fig. 1, it can be seen that the timepiece of which the operation is shown also comprises a number of correction mechanisms arranged to be manually actuated by the wearer of the timepiece. First, as already mentioned, a time change mechanism (reference numeral 101) is interposed between the motion work 106 and the hour wheel set 107. As will now be explained, the mechanism 101 can be controlled in two different ways depending on whether the time change relates to an actual change in longitude after e.g. a trip or to a change from winter time to summer time or vice versa. In the example illustrated, when the wearer of the timepiece changes time zone during travel, he can correct the time indication by means of the control stem 131 of the timepiece. To do this, he must pull stem 131 to position T2 before rotating the crown to move the hour hand forward or backward in a series of hour jumps. As seen above, the time wheel set 107 drives the calendar mechanism 121 and the year cam 111. In addition, hour wheel set 107 also drives ball 117 to rotate about the first axis. It will therefore be understood that the year cam 111, the calendar mechanism 121 and the sunrise and/or sunset indicating mechanism 115 are arranged to advance synchronously not only when they are driven by means of the drive mechanism 103 but also when they are driven manually forwards or backwards by means of the control stem 131 in the position T2.

In the example illustrated, the wearer of the timepiece can move the time indication forward or backward by just an hour by pressing on the push member P2 when switching from winter time to summer time or vice versa. Pressing on the pusher P2 actuates not only the time-varying mechanism 101 but also the disengaging mechanism 133 synchronously to disengage the second kinematic chain 120. It will be appreciated that disengaging the second kinematic chain when switching from summer to winter or vice versa prevents movement of the hour hand from affecting the relative angular position of the dark hemisphere 113 with respect to the sphere 117.

The timepiece of this example includes, in addition to the time changing mechanism 101, a time setting mechanism of a conventional type. This time-setting mechanism allows the wearer of the timepiece to set the time by using the control stem 131. To do this, he must move stem 131 to position T3 before rotating the crown. As in most current timepieces, the time-setting mechanism is arranged to drive a motion work 106, which motion work 106 in turn drives a minute wheel set 105 and an hour wheel set 107. As in the case of the preceding containing correction of the time zone, the hour wheel set 107 drives the calendar mechanism 121 and the year cam 111 via the third kinematic chain 118. In addition, hour wheel set 107 also drives ball 117 to rotate about the first axis. It will be appreciated that the year cam 111, the calendar mechanism 121 and the sunrise and/or sunset indicating mechanism 115 are arranged to advance synchronously also when they are driven manually forwards or backwards by means of the control stem 131 in the position T3.

Finally, the calendar mechanism of the timepiece of the present embodiment also includes a mechanism for correcting the month display device 125 of the calendar mechanism 121. When the wearer of the timepiece wishes to correct the month indication, for example after the timepiece has stopped for an indefinite period of time, he can advance the month indication step by actuating the pusher P1. According to this example, the actuation of the pusher P1 by the timepiece wearer has the effect of driving the date wheel 123 in rotation at high speed. The correction mechanism is arranged so that a single press on the pusher is sufficient to advance the date wheel by one full turn if required. However, the movable stopper also included in the correction mechanism has the following functions: after the passage of the 31 st day of the month, the date wheel is stopped as soon as it reaches the angular position corresponding to the indication of the first day of the month. On the first day of the shift from the last day of the month to the next month, the date wheel actuates the month driving means 127, which has the effect of increasing the month display means 125 by one. Therefore, it will be appreciated that this month display correction mechanism has the advantage of allowing the link between the date and the month to be maintained during the correction. The correction mechanism that has just been described is known as such. This correction mechanism is described in european patent publication EP2503410 entitled "Calendar mechanism comprising a quick month corrector". This document is incorporated by reference into the present patent application.

As already explained, the date display device 123 is arranged to drive the year cam 111 via the third kinematic chain 118. Further, according to the first embodiment, the third kinematic chain 118 employs a chain disposed downstream of the date wheel and having 1: 12 in the form of a reduction gear train. Under these conditions, it will be understood that the month display correction mechanism simultaneously corrects the angular position of the year cam 111, since the month correction is combined with the rapid advance of the date.

Fig. 2, which is attached, is a very similar diagram to that of fig. 1, but shows kinematic connections associating different mechanisms of a timepiece according to a second exemplary embodiment of the invention. As will be seen, the second embodiment is very similar to the first embodiment, in particular both the calendar mechanism and the correction mechanism arranged to be actuated by the wearer of the timepiece are the same as described in relation to the first embodiment. Fig. 2 shows a drive mechanism 203 incorporating a drive member, a speed regulation member and an escapement, a minute wheel set (reference numeral 205) integral with the minute display member and arranged to be driven by the drive mechanism at a rate of one revolution per hour, an hour wheel set 207 rotating integrally with the hour display member, a motion work mechanism 206 connecting the minute wheel set with the hour wheel set so that the hour wheel set is driven at a rate of one revolution per 12 hours, a time change mechanism (reference numeral 201) interposed between the motion work mechanism 206 and the hour wheel set 207, a tilt angle control mechanism (reference numeral 209) including an annual cam 211 and a cam follower (not shown), a sunrise and/or sunset indicating mechanism (reference numeral 215) including a sphere 217 representing the earth and a hemispherical housing 213 arranged concentrically with the sphere.

Fig. 2 also shows a calendar mechanism 221, which calendar mechanism 221 comprises in particular a date display for displaying a date 223 arranged to be driven via the time wheel set 207 and a month display 225 arranged to be driven by the date display via a month-wise drive (reference numeral 227). According to a second embodiment constituting the subject of the invention, the date display means 223 comprise a date wheel (not shown) and the monthly drive 227 is arranged to increment the month display means 225 by one each time the date wheel reaches a position corresponding to the first day of the next month from a position corresponding to the last day of the month. As in the case of the foregoing with respect to the first embodiment, the calendar mechanism 221 of the timepiece according to the second embodiment is preferably a perpetual calendar mechanism or an annual calendar mechanism. Further, according to the present invention, the date display mechanism 223 is arranged to drive the year cam 211 via the third kinematic chain 218. In the illustrated example, the third kinematic chain may be the same as the kinematic chain 118 described above with respect to the first exemplary embodiment.

In the second embodiment, as in the first embodiment, the relative motion of the hemisphere 213 and the sphere 217 is the result of a combination of different rotations about two perpendicular axes intersecting at the center of the sphere. However, according to the second embodiment, the dark hemisphere 213 makes two rotations at the same time because the sphere 217 is not driven. This mode of operation can be achieved by the fact that the support (not shown) on which the dark hemisphere 213 is mounted is a rotating support. Still referring to fig. 2, it will be appreciated that in the illustrated embodiment, wheel set 207 is connected to a rotary support (not shown) by a kinematic chain 220 (hereinafter "second kinematic chain 220"). The arrangement of the indication means 215 and the second kinematic chain 220 may, for example, conform to the description in one or the other of the european patent documents EP2977832 and EP 3007012. Both of these documents are incorporated by reference in this specification.

Referring again to fig. 2, it can be seen that reference mechanism 216 is interposed between tilt control mechanism 209 and indicating mechanism 215. It can be seen that mechanism 216 includes an output connected to indicating mechanism 215 and includes two inputs. Kinematic connection 221 (referred to as "fourth kinematic chain" 221) connects time wheel set 207 with the first of the two inputs. The mechanism 216 is thus driven by the first input, via which the hour wheel set is referred to as the "drive input". It can also be seen that the cam follower (not shown) is connected to the second input by a kinematic chain 212 (referred to as "first kinematic chain 212") arranged to transmit the variation of the annual cam profile. The mechanism 216 is therefore controlled by the profile of the year cam 211 via its second input, referred to as the "control input". Just as the second kinematic chain 220, the output of the mechanism 216 is arranged to drive the indicator mechanism at a rate of one revolution per 24 hours. However, the mechanism 216 drives the indicating mechanism at some offset relative to the second kinematic chain 220. The mechanism 216 may be implemented in many ways without departing from the scope of the invention. It may be, for example, a differential mechanism, in particular as described in european patent No. ep 2977832. It may also be a release mechanism, in particular as described in european patent No. ep 3007012.

Referring now to fig. 3A and 3B, a time change mechanism, generally indicated by reference numeral 101, will now be described in more detail. Recall that mechanism 101 has been shown in fig. 1 as interposed between motion work 106 and hour wheel set 107. Further, the mechanism 201 shown in fig. 2 may be the same as the mechanism 101. The mechanism 101 comprises a first tube 2, called inner tube, the first tube 2 being intended to be mounted in a conventional manner for rotation about a rotation axis X on a cannon-pinion shaft C (shown in fig. 1) driven by a drive mechanism 103. The inner tube 2 carries a hand 4 forming an hour hand, the hand 4 being pressed from the outside onto the free end of the inner tube 2 projecting from the mechanism 101.

The inner tube 2 thus constitutes an hour wheel tube and it carries a first outer gear 6, called the lower gear, comprising a plate 7. It should be pointed out here that advantageously this lower gear 6 forms an hour wheel and it meshes with the gear 8 (partially shown) of the motion work 106 (fig. 1). In normal operation, the hour wheel 6 receives time information transmitted by the gear wheel 8 of the motion work, which, as will be seen below, transmits this information indirectly to the inner hour wheel tube 2 and the hands 4. In fact, the lower hour wheel 6 is mounted to rotate freely on the hour wheel tube 2. To this end, the end of the hour wheel tube 2 opposite to its free end carrying the hands 4 comprises a collar 10, which collar 10 forms a shoulder that freely supports a star wheel 12, the lower hour wheel 6 being fixedly held on the star wheel 12. The star wheel 12 comprises a plate 13, an outer ring gear 14 and a circular flange 16, the circular flange 16 being arranged below the plate 13 in a manner peripherally adjacent to the ring gear 14, behind the ring gear 14 and coaxially thereto.

The hour wheel 6 is held fixedly on the side of the star wheel 12 against the toothing 14 of the star wheel 12. In practice, the hour wheel 6 is externally press-fitted onto the flange 16, pressed and/or riveted thereto, via the central portion of its plate 7 with the aperture. The star wheel 12 and the hour wheel 6 thus rotate directly in one piece and, in the present case, form a single piece which is placed on the hour wheel tube 2 as a result of their assembly. The star wheel 12 and the hour wheel 6 can thus be moved together at the same time via the gear wheel 8 of the motion work.

The time varying mechanism further comprises two drive disks 20, the drive disks 20 being stepped and each having a cylindrical base 22, with a post 24 extending in a perpendicular manner from the cylindrical base 22. Said discs are engaged in the ring gear 14 of the star wheel 12 at rest via their base 22 and they rest freely via this base and on the side (no reference numeral) of the plate 7 of the hour wheel 6. This rest position is also shown in the top view of fig. 3B. The disc 20 is also retained elastically in the ring gear 14 in this rest position by elastic return means 26, where the elastic return means 26 are formed by a closed annular spring mounted coaxially with the star wheel 12 and acting radially on the outer periphery of the base 22 of the disc 20. It should be noted here that the spring 26 is freely mounted against the drive disk 20, without using any fixed attachment on the mechanism 1. The spring 26 also rests freely against and more specifically against the plate 7 of the hour wheel 6. The spring 26 is therefore self-supporting and self-centering.

The time change mechanism further includes a second tube 30 called an outer tube, and the second tube 30 includes a guide hole 31 and is externally attached to the first tube 2 via the guide hole 31. This second tube 30 carries a second external gear 32, arranged above the lower hour wheel 6 and called "upper gear". It should be noted here that the upper and lower positions of the gears 6 and 32 refer to the diagram of fig. 3A, which shows the correction mechanism with the hour hand above. The upper gear 32 comprises a plate 33 and it meshes, via its external toothing, with a gear wheel 34, the gear wheel 34 in turn being driven by a correction member that can be actuated manually from the outside of the timepiece.

The upper gear 34 thus forms a time-varying gear which, as will become clear, can directly correct the position of the hour wheel tube 2 and of the pointer 4 without acting on the motion work and therefore without destroying other time information such as minutes and seconds, which are usually kinematically connected with the hour wheel tube 2 via said motion work. Advantageously, the outer tube 30 is press-fitted onto the inner hour wheel tube 2 from the outside and it is thus fixed thereto. The two tubes are thus rotated in one piece and they can move together. It will be appreciated that the hour wheel tube 2, outer tube 30 and upper gear 34 together form an hour wheel set 107. The upper correction gear 34 can thus act on the inner hour wheel tube 2 via the outer tube 30.

It should be noted that the hour wheel tube 2 is also driven by the motion work mechanism 106 and in particular by the gear wheel 8 of the motion work mechanism during normal operation. This is why the plate 33 of the correction wheel 32 is provided with radial grooves 36 in which the uprights 24, which can translate radially, are freely engaged in the radial grooves 36. Thus, when the star wheel 12 itself is driven by the hour wheel 6, the disc 20 can drive the correction gear 32 and the two tubes 2 and 30 in rotation.

In order to change to another time zone, the user of the timepiece must rotate the correction wheel 34; the disk 20 is then angularly displaced and jumps in the toothing 14 of the star wheel 12 (while the star wheel 12 and the hour wheel 6 remain stationary), so that the spring 26 is oval. The disc 20 then returns to the rest position in the ring gear 14 of the star wheel 12, but offset with respect to the position of fig. 3B. The pointer 4 then indicates another time zone. It should be noted that although the ring gear of the star wheel 12 has 12 teeth (to indicate 12 hours) in the figures, the ring gear may have 24 teeth for application to a 24 hour timepiece.

It should also be clear that various alterations and/or modifications apparent to those skilled in the art may be made to the embodiments constituting the subject matter of the present description without departing from the scope of the invention as defined by the appended claims.

Claims (19)

1. Timepiece comprising a timepiece movement, a calendar mechanism (121) and a sunrise and sunset indicating device (109, 115) taking into account seasonal variations, the timepiece movement comprising a minute wheel set (105), a motion work (106), an hour indicating member and a time wheel set (107), the time wheel set (107) rotating integrally with the hour indicating member and being arranged to be driven by the minute wheel set (105) via the motion work (106) at a speed of one revolution per 12 hours or at a speed of one revolution per 24 hours, the calendar mechanism (121) comprising a date display device (123) arranged to be driven via the time wheel set (107) and a month display device (125) arranged to be driven by the date display device, the sunrise and sunset indicating device comprising a sphere (117) representing the earth, a support and a ring (113a) mounted concentrically with the sphere on the support and arranged to indicate the position of the earth's boundary line, the sphere (117) being arranged to be driven in rotation at a rate of one revolution per 24 hours about a first axis corresponding to the polar axis of the earth, and the ring (113a) being mounted on the support so as to be also pivotable relative to the sphere (117) about a second axis intersecting the first axis perpendicularly at the center of the sphere, the sunrise and sunset indicating device further comprising a year cam (111), a cam follower and a first kinematic chain (112), the year cam (111) having a profile representative of the inclination of the sun with respect to the equatorial plane and being arranged to be driven in rotation at a rate of one revolution per year, the cam follower being arranged to cooperate with the year cam, the first kinematic chain being arranged to connect the cam follower with the ring (113a) so that the plane contained by the ring forms an angle with the first axis, this angle is equal to the angle of inclination of the sun with respect to the equatorial plane; said timepiece movement including a second kinematic chain (120) connecting the time wheel set (107) with the ball (117) in order to drive the ball at a rate of one revolution per 24 hours, said timepiece movement including, on the one hand, a manually actuatable time varying mechanism (101) and, on the other hand, a disengagement mechanism (133), which time varying mechanism (101) is arranged to pivot the time wheel set (107; 2, 30, 32) step-wise independently of the travel gear (106; 8), said disengagement mechanism (133) being arranged to disengage the second kinematic chain (120) when the time varying mechanism (101) pivots the time wheel set to change from summer time to winter time or from winter time to summer time, so that the ball can be driven at a rate of one revolution per 24 hours without being affected by the summer/winter time correction, and the year cam (111) is arranged to be driven by the date display device (123) via a third kinematic chain (118).

2. Timepiece movement according to claim 1, including a first hour wheel (6), which meshes with the motion work (8; 106) and is called a motion work hour wheel, and a second hour wheel (32), which is called an hour wheel, integral with the set of hour wheels (2, 30, 32; 107), and the time-varying mechanism (101) including disengageable coupling means (12, 20, 36) arranged to rotate the first (6) and second (32) hour wheels integrally in one or the other of a plurality of predetermined relative angular positions, which are equidistant and spaced from each other by an angle corresponding to the distance travelled by the hour-indicating member (4) per hour.

3. Timepiece according to claim 1, characterised in that the calendar mechanism (121) comprises a month display correction mechanism for correcting a month display (125), arranged to simultaneously correct the angular position of the year cam (111) so that the month display and the year cam remain synchronised after correction.

4. Timepiece according to claim 1, characterised in that the date display device (123) comprises a date wheel and in that the third kinematic chain (118) comprises a 16-tooth pinion integral with the date wheel, a 48-tooth pinion meshing with the 16-tooth pinion and integral with a 14-tooth intermediate pinion, which in turn meshes with a 56-tooth pinion integral with the year cam (111).

5. The timepiece according to claim 1, characterised in that the calendar mechanism (121) is a perpetual calendar mechanism or a perpetual calendar mechanism.

6. Timepiece according to claim 1, wherein the support on which the ring (113) is mounted is stationary.

7. Timepiece according to claim 1, characterized in that the sunrise and sunset indicating means (115, 109) taking account of seasonal variations comprise a casing (113) arranged concentrically to the sphere (117) representing the earth, arranged to delimit one part of the earth at night from another part at daytime, and having the general shape of a hemisphere and a generally circular edge forming the ring (113a) arranged to indicate the position of the earth's boundary line.

8. Timepiece according to claim 7, wherein the second axis is substantially collinear with the diameter of the ring (113a), and the case (113) carries two pivots extending from the two ends of the diameter, the two pivots pivoting on the support.

9. Timepiece according to claim 8, characterised in that the edge of the case (113) has two notches arranged at diametrically opposite positions in a middle portion between the two pivots.

10. Timepiece comprising a timepiece movement, a calendar mechanism (221) and a sunrise and sunset indicating device (209, 215) taking into account seasonal variations, the timepiece movement comprising a minute wheel set (205), a motion work (206), an hour indicating member and a time wheel set (207) rotating integrally with the hour indicating member and arranged to be driven by the minute wheel set (205) via the motion work (206) at a speed of one revolution per 12 hours or at a speed of one revolution per 24 hours, the calendar mechanism (221) comprising a date display device (223) arranged to be driven via the time wheel set (207) and a month display device (225) arranged to be driven by the date display device, the sunrise and sunset indicating device comprising a sphere (217) representing the earth, a support and a ring (213a) mounted concentrically with the sphere on the support and arranged to indicate the position of the earth's boundary line, said ring (213a) being arranged to be driven in rotation at a rate of one revolution per 24 hours about a first axis corresponding to the polar axis of the earth and being mounted on said support so as to also pivot relative to the sphere (217) about a second axis intersecting the first axis perpendicularly at the centre of the sphere, said sunrise and sunset indicating device further comprising a year cam (211), a cam follower and a first kinematic chain (212), said year cam (211) having a profile representative of the inclination of the sun with respect to the equatorial plane and being arranged to be driven in rotation at a rate of one revolution per year, said cam follower being arranged to cooperate with said year cam, said first kinematic chain (212) being arranged to connect said cam follower with said ring (213a) so that the plane contained by said ring forms an angle with said first axis, this angle is equal to the angle of inclination of the sun with respect to the equatorial plane; said timepiece movement including a second kinematic chain (220) connecting the hour wheel set (207) to the ring (213a) in order to drive the ring at a rate of one revolution per 24 hours, said timepiece movement including, on the one hand, a manually actuatable time-varying mechanism (201) and, on the other hand, a disengagement mechanism (233), which time-varying mechanism (201) is arranged to pivot the hour wheel set (207; 2, 30, 32) step-wise independently of the travel gear (206; 8), said disengagement mechanism (233) being arranged to disengage the second kinematic chain (220) when the time-varying mechanism (201) pivots the hour wheel set to change from summer time to winter time or from winter time to summer time, so that the ring can be driven at a rate of one revolution per 24 hours without being affected by the summer/winter time correction, and the year cam (111) is arranged to be driven by the date display device (223) via a third kinematic chain (218).

11. Timepiece movement according to claim 10, including a first hour wheel (6), which meshes with the motion work (8; 206) and is called a motion work hour wheel, and a second hour wheel (32), which is called an hour wheel, integral with the set of hour wheels (2, 30, 32; 207), and the time-varying mechanism (201) includes disengageable coupling means (12, 20, 36) arranged to rotate the first (6) and second (32) hour wheels integrally in one or the other of a plurality of predetermined relative angular positions, which are equidistant and spaced from each other by an angle corresponding to the distance travelled by the hour-indicating member (4) per hour.

12. The timepiece according to claim 10, characterized in that the calendar mechanism (221) comprises a month display correction mechanism for correcting a month display (225), which is arranged to simultaneously correct the angular position of the year cam (211) so that the month display and the year cam remain synchronized after correction.

13. Timepiece according to claim 10, characterised in that the date display device (223) comprises a date wheel and in that the third kinematic chain (218) comprises a 16-tooth pinion integral with the date wheel, a 48-tooth pinion meshing with the 16-tooth pinion and integral with a 14-tooth intermediate pinion, which in turn meshes with a 56-tooth pinion integral with the year cam (211).

14. The timepiece according to claim 10, characterized in that the calendar mechanism (221) is a perpetual calendar mechanism or a perpetual calendar mechanism.

15. Timepiece according to claim 10, wherein the support on which the ring (213a) is mounted rotates, and the second kinematic chain (220) comprises a train of wheels connecting the hour wheel set (207) with the rotating support.

16. Timepiece according to claim 10, characterised in that the sunrise and sunset indicating means (215, 209) taking account of seasonal variations comprise a casing (213) arranged concentrically to the sphere (217) representing the earth, arranged to delimit one part of the earth at night from another part at daytime, and having the general shape of a hemisphere and a generally circular edge forming the ring (213a) arranged to indicate the position of the earth's boundary line.

17. The timepiece according to claim 16, characterised in that the second axis is substantially collinear with the diameter of the ring (213a), and in that the case (213) carries two pivots extending from the two ends of the diameter, which pivot on the support.

18. Timepiece according to claim 17, wherein the edge of the case (213) has two notches arranged at diametrically opposite positions in a middle portion between the two pivots.

19. Timepiece according to claim 1 or 10, wherein the timepiece is a wristwatch.