EP4113218B1 - Mechanism for combined display of a lunar calendar and the phases of the moon for a timepiece movement - Google Patents

Description

Technical field

The present invention relates to a mechanism for displaying a lunar date, for a watch movement, comprising a date wheel carrying a display hand arranged to move opposite a lunar date indicator scale, the date wheel being intended to be driven by a drive wheel of the watch movement in such a way that the display hand is capable of traveling along the indicator scale in a maximum of thirty days.

State of the art

While most timepieces with a calendar function include a watch movement whose operation is based on the Gregorian calendar, which is a solar calendar, such display mechanisms based on the lunar cycle, for example the Hijri, Jewish, Chinese, Japanese or Korean calendars, are also known in the prior art. Generally, in the remainder of the text, the expression "lunar calendar" will be used to designate all the calendar systems used in different cultures or nations that are based on the cycles of the Moon.

For example, Parmigiani Fleurier has been marketing a perpetual Hegirian calendar watch model in its Tonda range (registered trademark) since the beginning of 2020. This model is presented here: http://fr.worldtempus.com/article/montres/style-et-tendance/parmigiani-fleurier-calendrier-perpetuel-hegirien-28202.html .

As is the case with this model, watches with a calendar function sometimes feature an additional mechanism for displaying the phases of the Moon. Indeed, the aforementioned timepiece features a display of the Hijri calendar arranged in a counter located at nine o'clock on the dial, as well as a mechanism for displaying the phases of the Moon arranged in a counter located at six o'clock.

More precisely, the mechanism for displaying the phases of the Moon is conventional here, since it uses a disc bearing a representation of the Moon rotating behind the dial, to reveal a portion of the disc through an aperture whose specific outline defines a mask making it possible to represent the different phases of the Moon according to its evolution during a lunar month.

A large number of different constructions are known to implement a cooperation between a disc bearing a representation of the Moon and a mask in order to display the phases of the Moon, preferably with the greatest possible precision. These display mechanisms are more or less bulky on the dial of the corresponding timepieces, but generally make the latter attractive to a certain category of customers.

The document RU 2572466 C1 discloses a mechanism for displaying the lunar date by moving a central indicator hand opposite a circular peripheral scale of graduations extending from 1 to 30. This document provides an alternative embodiment according to which the indicator hand also carries a ring defining an aperture cooperating with the dial to display the phases of the Moon. For this purpose, a dark shape is drawn in the center of the dial, this being adapted to illustrate the phases of the Moon at each instant in collaboration with its lighter peripheral region and with the aperture. With such a mechanism, the combined display of the lunar date and the phases of the Moon occupies the entire corresponding dial.

Mechanisms of alternative construction are also known in connection with Gregorian calendars, thanks to which a less cumbersome display of the phases of the Moon can be implemented, generally at the expense of the precision of the display. Thus, for example, the company Jaquet Droz marketed in the early 2000s a wristwatch ("Les Lunes", with triple calendar) with a retrograde display of the phases of the Moon comprising five representations of the Moon associated with five successive instants of a lunar cycle and a retrograde hand, driven to position itself successively opposite these representations according to the progress in a lunar cycle. The (Gregorian) date was displayed by means of a central date hand moving opposite a scale of 31 graduations arranged on the periphery of the dial. This same company presented in 2013 an evolution of its display mechanism making it both less bulky and more precise (in its "Eclipse" collection still marketed today). Indeed, the current mechanism for displaying the phases of the Moon includes a fixed representation of the Moon opposite which moves a disc-shaped cover carried by the end of a hand driven in a complex movement. As regards the display of the associated (Gregorian) date, several variants are currently marketed: either the date is displayed by a central hand moving in relation to a scale of 31 graduations arranged on the periphery of the dial, or it is displayed by a date hand driven retrogradely to move in relation to a scale of 31 graduations extending along a circular sector.

While juxtaposing the moon phase and date displays on a watch dial requires the use of a significant portion of the corresponding dial, it has of course also been proposed to superimpose them to limit the surface area they occupy together. For example, the Montblanc company markets a model called "Star Legacy Moonphase" (visible here: https://www.montblanc.com/en-ch/wrist-watch_cod10163292706843707.html ) in which the date and moon phase displays (both conventional) are arranged coaxially. The dimensions of the moon phase display are limited by the diameter of the dial, so that it does not encroach on the central hand, which results in a date indicator scale whose values have a reduced height and are difficult to read. In addition, the gain in display surface area comes at the expense of the thickness of the display mechanism due to the coaxiality of the two displays.

It is clear from the above that it remains interesting for a manufacturer of watch mechanisms or movements to be able to offer a combined mechanism for displaying the date and moon phases which is both precise and legible, compact and of simple construction.

Disclosure of the invention

A main object of the present invention is therefore to propose a mechanism for displaying a lunar calendar combined with a display of the phases of the Moon of appearance and construction different from those of known display mechanisms and which is both precise and readable, compact and of simple construction.

• par le fait qu'il soit agencé de telle manière que le mobile de quantième présente un mouvement rétrograde, l'échelle indicatrice étant ouverte,
• par le fait qu'il comporte une bande colorée s'étendant sensiblement d'une extrémité à l'autre de l'échelle indicatrice en étant sensiblement parallèle à cette dernière, la bande colorée présentant une portion claire destinée à illustrer au moins partiellement la Lune, et une portion sombre complémentaire, la proportion entre les portions claire et sombre variant le long de l'échelle indicatrice pour prendre en compte l'évolution de l'apparence de la Lune en fonction du quantième lunaire, et
• par le fait que l'aiguille d'affichage présente un guichet sensiblement circulaire agencé pour se déplacer en regard de la bande colorée et en délimiter une portion d'affichage, à chaque instant, pour afficher les phases de la Lune.

To this end, the present invention relates more particularly to a display mechanism of the type indicated above, characterized

• by the fact that it is arranged in such a way that the date wheel exhibits a retrograde movement, the indicator scale being open,
• by the fact that it comprises a colored band extending substantially from one end to the other of the indicator scale while being substantially parallel to the latter, the colored band having a light portion intended to illustrate at least partially the Moon, and a complementary dark portion, the proportion between the light and dark portions varying along the indicator scale to take into account the evolution of the appearance of the Moon according to the lunar calendar, and
• by the fact that the display hand has a substantially circular window arranged to move opposite the colored band and delimit a display portion thereof, at each instant, to display the phases of the Moon.

These features provide a combined display of the lunar date and the phases of the Moon that is extremely compact and simple in construction, without compromising either the readability of the date display or the accuracy of the display of the phases of the Moon. Indeed, as a non-limiting example, the Hegirian calendar being a lunar calendar, its months have a variable length, either twenty-nine days or thirty days, to take into account the actual duration of the lunar cycle or synodic period (approximately twenty-nine days, twelve hours and forty-four minutes). The fact that a single display hand simultaneously indicates the lunar date and the phases of the Moon makes it possible to ensure that the moon phases are displayed correctly at all times, based on the lunar calendar displayed.

Preferably, it can be provided that the date wheel is rotatable, the indicator scale and the colored band then extending along two arcs of a circle which are substantially parallel to each other.

• comporte un mobile de rétrograde comprenant une roue, destinée à être entrainée par le mobile d'entrainement du mouvement horloger pour faire un tour sur elle-même en trente jours maximum, ainsi qu'une came en colimaçon,
• qu'il comporte un râteau portant un bec coopérant avec la périphérie de la came ainsi qu'un secteur denté agencé en prise avec une denture du mobile de quantième, et
• qu'il comporte un organe de rappel élastique agencé pour tendre à maintenir le bec en appui contre la périphérie de la came.

For this purpose, it is preferable to provide that the display mechanism

• includes a retrograde wheel comprising a wheel, intended to be driven by the drive wheel of the watch movement to complete one revolution on itself in a maximum of thirty days, as well as a spiral cam,
• that it comprises a rack carrying a beak cooperating with the periphery of the cam as well as a toothed sector arranged in engagement with a toothing of the date wheel, and
• that it comprises an elastic return member arranged to tend to keep the beak pressed against the periphery of the cam.

The present invention also relates to a watch movement comprising a drive wheel arranged to drive the date wheel of a display mechanism according to the preceding characteristics.

More particularly, it is advantageous to provide that the drive wheel is arranged in such a way that the date wheel exhibits a movement, once per day, such that the display hand travels the indicator scale in a maximum of thirty days.

According to a preferred embodiment, it is also possible to provide that the watch movement comprises a short month correction member arranged to advance the display hand directly from the value 29 of the indicator scale to the value 1 at the end of the last day of the twenty-nine-day months.

According to an advantageous embodiment variant, it can be provided that the drive wheel is a date disc.

The present invention also relates to a timepiece comprising a watch movement according to the preceding characteristics.

Brief description of the drawings

• la figure 1 représente une vue de face partielle simplifiée d'un exemple de pièce d'horlogerie selon un mode de réalisation préféré de la présente invention, et
• la figure 2 représente une vue de face simplifiée d'une partie d'un mouvement horloger selon un mode de réalisation préféré de la présente invention.

Other characteristics and advantages of the present invention will appear more clearly on reading the detailed description of a preferred embodiment which follows, made with reference to the appended drawings given by way of non-limiting example and in which:

• there Figure 1 represents a simplified partial front view of an example of a timepiece according to a preferred embodiment of the present invention, and
• there Figure 2 represents a simplified front view of a part of a watch movement according to a preferred embodiment of the present invention.

Method(s) of carrying out the invention

There Figure 1 represents a simplified view of a part of a timepiece 1 according to the present invention.

The elements of the timepiece 1 are not shown for the sake of simplification and to the extent that they do not play a particular role in the implementation of the present invention. Furthermore, the timepiece 1 is deliberately presented here in a basic form for the same sake of simplification, and the person skilled in the art will not encounter any particular difficulty in adapting the present teaching according to his own needs, to produce a timepiece whose elements not directly linked to the implementation of the invention may differ from those presented here, without departing from the scope of the invention as defined by the appended claims.

Timepiece 1 includes a clockwork movement (which will be partially described in relation to the Figure 2 ) surmounted by a dial 2 bearing indexes 4 for displaying the current time in relation to central hands for the current hours 6 and the current minutes 8.

In accordance with the present invention, the timepiece 1 also comprises a hand 10 for retrograde displaying the lunar date. The hand 10 is intended to be driven by the watch movement in such a way that its free end moves opposite a fixed indicator scale 12 of the lunar date carried by the dial 2. As mentioned above, lunar calendars typically have months of twenty-nine or thirty days, so the indicator scale 12 includes thirty date graduations, only odd values being indicated here as a non-limiting example.

Furthermore, the dial 2 further comprises a fixed colored band 14 extending substantially from one end to the other of the indicator scale 12 while being substantially parallel to the latter. The colored band 14 has a light portion 16 intended to at least partially illustrate the Moon, and a complementary dark portion 18, the proportion between the light 16 and dark 18 portions varying along the indicator scale 12 to take into account the evolution of the appearance of the Moon depending on the lunar calendar.

As will be understood, a broad interpretation of the term "colored" must be considered here, the really important characteristic here being to be able to clearly distinguish the two portions 16 and 18 from each other, which could also be suitable with a white portion 16 and a black or gray portion 18. The dark portion 18 could also include light patterns symbolizing stars, in a known manner.

It can be seen that the hand 10 has a substantially circular window 20, arranged here near its free end to move opposite the colored band 14 and delimit a display portion thereof, at each instant, to display the phases of the Moon.

Thanks to this arrangement, the window 20 scans the entire colored band 14 during a given month and allows the phases of the Moon to be displayed precisely throughout the month (lunar, for example Hijri), from and until the new Moon, on the first and thirtieth of the month, passing through the full Moon, on the fifteenth of the month.

There Figure 2 represents a front view of a part of a clock movement 22 making it possible to control the movements of the hand 10 to implement the display which has just been described.

The watch movement 22 comprises a display mechanism 24 of the lunar calendar of the basic type, for non-limiting illustration purposes. By analogy with the complication called "simple (Gregorian) calendar", the movement watchmaker 22 which will be partially described below is intended to control the movements of the hand 10 in such a way that it advances each month by one step per day, to pass from the value 1 of the indicator scale 12 to the index corresponding to the 30, before returning to the position located opposite the 1. When a given month has only twenty-nine days, the user can correct the value displayed for the lunar calendar, from the 30th to the ^1st of the following month, by acting on an external control member, for example a crown (not visible) carried by a correction stem 26. Of course, a dedicated pusher or corrector could be provided as an alternative.

The 22 watch movement can advantageously include a basic watch caliber including a calendar mechanism, of the simple calendar type, in the most basic version. This calendar mechanism typically includes a date disc or ring driven from a twenty-four-hour wheel to advance one step per day and complete one rotation on itself in thirty-one days. Most of the time, this date disc is driven by internal teeth.

Thus, it is possible to replace the conventional date disc with a date disc 28 slightly modified to have external teeth 30 in addition to its conventional internal teeth. The date disc 28 can then act as a drive wheel for the lunar date display mechanism 24, acting on the latter once a day.

The display mechanism 24 of the lunar calendar comprises a frame 32, preferably secured to the plate of the basic watch caliber, carrying a star 34 whose branches cooperate with the external toothing 30 of the date disc 28. The star 34 is secured to a pinion 36 meshing with a wheel 38 of a retrograde wheel set also comprising a spiral cam 40.

The frame 32 further carries a rotating rack 42, carrying a beak 44 arranged to cooperate with the periphery of the cam 40, as well as a toothed sector 46 arranged in engagement with a wheel 48 of a date wheel 50 carrying the hand 10 for displaying the lunar date and the phases of the Moon.

An elastic return member 52, here taking the form of a spiral spring, acts on the arbor of the date wheel set 50 to tend to rotate the hand 10 in the counterclockwise direction as seen from the Figure 2 The rake 42 thus also tends to turn counterclockwise, which has the effect of keeping its beak 44 in permanent contact against the periphery of the cam 40.

A jumper 54 is also provided to ensure the maintenance of the angular orientation and the end of the jumps of the star 34, in a conventional manner.

It is understood from the above that the date disc 28 advances the star 34 by one step each day, which in turn drives the cam 40 in rotation, in the clockwise direction of rotation as seen from the Figure 2 , at an angle such that hand 10 passes from one date graduation to the next.

At the end of the thirtieth day of each thirty-day month, the beak 44 leaves the portion of the periphery of the cam 40 with the largest radius to fall onto its portion with the smallest radius under the effect of the action of the elastic return member 52. During this movement, the rack 42 pivots in the counterclockwise direction of rotation in such a way that the needle 10 suddenly passes from the index corresponding to 30 to graduation 1 of the indicator scale 12.

As mentioned above, when a month that has just ended had only twenty-nine days, the user must manually intervene on a short month correction organ, on the ^1st of the following month while hand 10 still points to the index corresponding to the 30th of the (previous) month, to advance star 34 by one step and drop beak 44 onto the portion of the periphery of cam 40 with the smallest radius, and thus move hand 10 to the value 1 of the indicator scale 12. The short month correction organ may also be actuated to set the date following a prolonged stoppage of watch movement 22.

Of course, it is possible to provide as an alternative that the display mechanism 24 includes a directly integrated short month correction organ, to correct the value of the date at the end of short months, in the manner of the complication called "annual calendar" in relation to the Gregorian calendar taking into account the difference in duration between the thirty-day months and the months of thirty-one days. A large number of technical solutions have already been presented in relation to the Gregorian calendar to carry out this type of correction, and the person skilled in the art will not encounter any particular difficulty in implementing such a short month correction member integrated into the display mechanism 24, without departing from the scope of the invention as defined by the appended claims. Alternatively, it is also possible to implement the display mechanism according to the invention in relation to a perpetual lunar calendar mechanism, such as for example the perpetual Hegirian calendar mechanism implemented in the watch mentioned above, marketed by Parmigiani Fleurier. Such a mechanism could in particular make it possible to ensure the driving of the wheel 38 in such a way that it makes one revolution on itself in twenty-nine days or in thirty days depending on the duration of the current month, sparing any intervention by the user.

Thanks to the features just presented, a combined display mechanism of a lunar calendar and moon phases is obtained, which is compact, precise, offers excellent readability and which, moreover, can be easily adapted to an existing mechanism.

The implementation of the present invention is not limited to certain particular characteristics as illustrated and described. Indeed, the person skilled in the art will not encounter any particular difficulty in adapting the present teaching to his own needs and implementing a display mechanism incorporating only part of these characteristics without departing from the scope of the present invention as defined by the claims. Thus, for example, the hand displaying the date and the phases of the Moon could have a retrograde translational movement, the indicator scale and the colored band being linear in this case. The drive wheel, in the watch movement, as well as the transmission chain to the date display wheel may take different forms while remaining within the scope of the invention as defined in the claims. The star could for example be pivoted in steps under the effect of the action of a lever. Alternatively, even if such a variant would present reduced readability, it it is possible to provide that the distribution between the light and dark portions of the colored band is carried out in such a way that the latter includes representations of the Moon arranged next to each other and illustrating the evolution of the phases of the Moon throughout the month, the number of representations of the Moon depending essentially on the length of the colored band.

Claims (8)

1. A display mechanism (24) for displaying a lunar date for a clock movement (22), comprising a date wheel (50) carrying a display hand (10) arranged to move opposite an indication scale (12) indicating the lunar date, said date wheel (50) being intended to be driven by a drive wheel (28) of the clock movement (22) in such a way that said display hand (10) is able to travel along said indication scale (12) in a maximum of thirty days,

   characterised in that it is arranged in such a way that said date wheel (50) has a retrograde movement, said indication scale (12) being open,

   in that it comprises a coloured band (14) extending substantially from one end of said indication scale (12) to the other, being substantially parallel to said indication scale, said coloured band (14) having a light portion (16) intended to illustrate at least part of the Moon, and a complementary dark portion (18), the proportion between said light (16) and dark (18) portions varying along said indication scale (12) to take account of the changing appearance of the Moon according to the lunar date, and

   in that said display hand (10) has a substantially circular window (20) arranged to move opposite said coloured band (14) and delimit a display portion thereof, at each moment, to display the phases of the Moon.
2. Mechanism (24) according to claim 1, characterised in that said date wheel (50) is rotatable, said indication scale (12) and said coloured band (14) extending along two arcs of a circle that are substantially parallel to each other.
3. Mechanism (24) according to claim 2, characterized

   in that it includes a retrograde mobile comprising a wheel (38), intended to be driven by the drive wheel (28) of the clock movement (22) to make one revolution in a maximum of thirty days, as well as a spiral cam (40),

   in that it comprises a rack (42) carrying a beak (44) cooperating with the periphery of said cam (40) as well as a toothed sector (46) arranged in engagement with a toothing of said date wheel (50), and

   in that it comprises an elastic return member (52) arranged to tend to maintain said beak (44) bearing against the periphery of said cam (40).
4. Clock movement (22) comprising a display mechanism according to one of the preceding claims, and a drive wheel (28) arranged to drive said date wheel (50) of said display mechanism (24).
5. Clock movement (22) as claimed in claim 4, characterised in that said drive wheel (28) is arranged in such a way that said date wheel (50) moves once a day such that said display hand (10) travels along said indication scale (12) in a maximum of thirty days.
6. Clock movement (22) according to claim 5, characterised in that it includes a short month correction device arranged to advance said display hand (10) directly from the value 29 of said indication scale (12) to the value 1 at the end of the last day of twenty-nine day months.
7. Clock movement (22) according to any one of claims 4 to 6, characterised in that said drive wheel (28) is a date disc.
8. Timepiece (1) comprising a clock movement (22) according to any one of claims 4 to 7.

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