HK1255859A1

HK1255859A1 - Calendar mechanism for a timepiece

Info

Publication number: HK1255859A1
Application number: HK18114935.9A
Authority: HK
Inventors: Kapetanovic Amel; Stahel Adrian; Forsey Stephen; Neboisa Christoph
Original assignee: Ct Time S.A.
Priority date: 2015-11-13
Filing date: 2016-11-11
Publication date: 2019-08-30

Description

Technical field

The present invention relates to the field of watchmaking and concerns, in particular, a calendar mechanism suitable for indicating information having a period varying according to at least one first cycle and one second cycle, such as a perpetual calendar.

State of the art

EP 1 351 104 describes a perpetual calendar mechanism. This calendar has a maximum month length of 31 days, which varies over a first 12-month cycle, and which has the sequence of 31-28-31-30-31-30-31-30-31-30-31 days per month. A second 4-year cycle of the Julian leap year is superimposed on this first cycle, which adds an extra day to the month of February. A removable tooth carried by a sliding lever interacts with a 24-hour wheel at the end of February of non-sextile years to advance the quantum of the indication from 28 directly to an indication of the following month. This indication is retracted in leap years so that the indication can show 29 hours before February, moving towards the 24th, and this is fragile.

EP 1 818 738 also incorporates a third 100-year cycle, to remove 29 February for years divisible by 100, and a fourth 400-year cycle to reinstate it for years divisible by 400.

The Islamic calendar is based on the lunar cycle, and includes a first cycle of 12 months, with odd months having 30 days, and even months having 29 days. To compensate for the difference between this cycle and the full Muslim year, the twelfth month of some years has 30 days instead of 29, according to a second cycle of 30 years. Several variations of this second cycle exist, but a commonly used variant defines the years in which the twelfth month has 30 days instead of 29 as follows: 2nd, 5th, 7th, 10th, 13th, 15th, 18th, 21st, 24th, 26th, and 29th.

These calendar mechanisms of earlier art are relatively complex, and require a lot of space in the movement.

The purpose of the present invention is to propose such a calendar mechanism which is simple, compact and reliable.

The Commission shall adopt implementing acts laying down the rules for the application of this Regulation.

More specifically, the invention relates to a calendar mechanism for a watch part, the said calendar mechanism being adapted to indicate information having a period varying according to at least one first cycle and one second cycle. first cycle means, for example, a month cycle in which the number of days in each month is invariable from one year to the next, for example from the first to the eleventh month of the Islamic calendar, or the months of January and March to December of the Western calendar (Julian or Gregorian). second cycle means, for example, a cycle of a different length from the first, for example, the number of 30 years that determines the number of days in the twelfth month of the Islamic calendar, the 4-year cycle of the Julian calendar, or the two-year cycle of the 400-day calendar that determines the number of days in February in order to give a complete indication of the number of cycles.

This mechanism consists of a monthly mobile comprising a wheel with a fixed number of teeth, which is chosen according to the maximum period of time for which the information is to be displayed.

The mobile also includes a swing arranged to move from an inactive to an active position and vice versa, with at least one tooth that can be removed from the mobile's perimeter. This tooth may be a conventional tooth extending into the plane of the swing, or a tooth extending perpendicular to that plane as a singing tooth, pin, ergot or similar, which are usually all considered to be teeth when they perform the same function.

The mechanism shall also include a drive mount consisting of a first drive organ arranged to interact with the fixed teeth and a second drive organ angularly offset from the first drive organ and arranged to interact with the removable tooth when the swing is in its active position.

The mechanism incorporates a first cam, the shape of which represents the variations of the period in question according to the first cycle, and a second cam, the shape of which represents the variations of the period in question according to the second cycle, and an indexing system in kinematic link with the wheel, the first cam and the second cam, adapted to index each of the said cams according to the said cycles.

A system for actuating the said pendulum is also incorporated in the mechanism, which comprises a first cam palpation device to come into contact with the first cam and a second cam palpation device to come into contact with the second cam, the said palpations being in kinematic link with each other and the actuation system being arranged to move the said pendulum from its inactive position to its active position under the control of each of the said cams.

Therefore, these two kinematically linked palpations allow the switch to be operated either according to the information carried by the first cam or according to the information carried by the second cam, so that it is controlled according to the overlap of the two cycles in order to display the desired complete cycle, and therefore the monthly moving is advanced by the appropriate number of steps at the end of each month.

The advantage is that the first cam and the second cam are each coaxial to the wheel and carried by the wheel, resulting in a particularly compact construction.

Each of these cams may be on the same side of the said wheel, or one on the first side of the said wheel, and the other on the opposite side.

In the latter case, the second palpation device extends advantageously through an opening in the wheel in order to be able to feel the cam on the side opposite to the first palpation device.

The advantage of the actuation system is that it includes a first lever fitted with the first palper and also a stop designed to make contact with the first swing in order to move it to its active position under the control of the first swing.

In one variant, not only the first but also the second palpation lever is carried by the first lever, which is a particularly compact arrangement.

In one variant, the actuating system includes an additional actuating motor in direct or indirect kinematic link with the first lever, which is arranged to move the said swing to its active position under the control of the second lever.

The advantage is that the additional drive is pivoted in relation to the wheel and includes an additional drive shaft designed to be supported against the said swing under the control of the said second shaft.

In one variant, the first cam is representative of the number of days in a month varying according to a first cycle, and the second cam is representative of the number of days in at least one particular month varying according to a second cycle, and the first cam is represented by a notch representing at least one month, the number of days of which is determined according to the second cycle. In a particular variant in which the first cycle has 12 months and the second cycle has 30 years, the first cam is represented by the number of days in the first to the 11th month, the notch corresponding to the 12th month, and the second cam is represented by the number of days in the 12th month, the number of days in the second cycle having 30 years. The notch in the first position of the second cam does not allow the number of days in the month to be determined by the cam to be influenced.

Alternatively, the first cycle has four years, the form of the first cam representing the number of days in February varies according to the first four-year cycle (i.e. 28 - 28 - 28 and then 28 or 29 (depending on the second cycle)), the notch corresponding to the month of February which could be leap year or not according to, for example, the Julian or Gregorian calendar.

The advantage of the mechanism is that it includes a second extra cam superimposed on the second cam, the combination of the second cam and the second extra cam defining a 400-year cycle, especially according to the Gregorian calendar. This avoids using a single cam with 400 sectors, and allows for the use of two simpler cams in superposition.

The advantage of this is that the swing has at least two removable teeth with the same spacing as two fixed teeth on the wheel. The mechanism is therefore reversible and maintains its indexation regardless of the direction of rotation of the drive unit.

It is advantageous to provide a day of the week display, preferably linked to the training mobile to easily indicate the day of the week.

Brief description of the drawings

Further details of the invention will be clearer by reading the following description, made by reference to the attached drawings in which: Fig. 1-3 are top-down views of a first embodiment of a calendar mechanism according to the invention in different positions;Fig. 4 is a schematic diagram illustrating the principle of operation of the calendar mechanism according to the invention;Fig. 5-8 are perspective and plan views of a second embodiment, seen from both sides of the mechanism; andFig. 9-11 are perspective views of a third embodiment, seen from both sides of the mechanism.

The method of implementation of the invention

Figures 1-3 show a schematic illustration of how a calendar mechanism 1 of the invention is made in the form of a Muslim calendar. In order to illustrate more clearly the interaction between the various components and to give a better appreciation of the depth in the figures, different cut-outs have been used.

Mechanism 1 includes a 3 month mobile, which includes a 4 wheel bearing 5 fixed teeth relative to wheel 4. The number of fixed teeth 5 is chosen based on the maximum number of days to display, including thirty in the illustrated case. An integer multiple of this number is also possible. Positioning of the 3 month mobile can be provided in a classic way by means of a jumper (not illustrated).

The 3 month mobile is driven by a 7 drive mobile, which has a first drive organ 7a fitted with four drive teeth or fingers separated by spaces, the latter being conformed to cooperate with the fixed teeth 5. The 7 drive mobile is arranged to be driven by itself by a basic movement (not shown) at a rate of one quarter turn per 24 hours, typically around midnight.

The 3 month mobile also features a 9 rocker, pivoted on wheel 4 at a pivot point 9a, which carries 11 removable teeth located in a different plane from the fixed 5 teeth and in solidarity with the 9 rocker. In the view from Figure 1, the 9 rocker and the 11 removable teeth are in their recessed - inactive - position while they are in their deployed - active - position in Figures 2 and 3. A booster spring (not shown) tends to keep the 9 rocker in its inactive position (Figure 1).

This second drive 7b is substantially similar in shape to the first drive 7a, but is angularly offset by 1/8 of a turn from the first drive 7a and is in a plane which allows it to cooperate with the removable teeth 11.

Therefore, if the removable teeth 11 are in their recessed position (Figure 1), the second drive 7b has no effect and for each quarter turn of the drive 7 the 3 month drive is rotated one step, i.e. one tooth in the illustrated case.

If the removable teeth 11 are in their active position (Figures 2 and 3), a quarter turn of the drive mobility 7 rotates the 3 month mobile one step by the interaction between the first drive 7a and the fixed teeth 5 and one step by the interaction between the second drive 7b and the removable teeth 11.

If the removable teeth 11 comprise only one tooth 11, the schedule 1 mechanism operates only in one direction of rotation. However, in the illustrated case where two removable teeth 11 are present and each overlap with a fixed pair of teeth of wheel 4 (or are offset from a fixed pair of teeth of wheel 4), with a separation similar or identical to the separation between two fixed teeth 5 of wheel 4, the schedule 1 mechanism operates in a reversible manner, i.e. the number of steps that the mobile month 3 takes following a drive in one or multiple directions (e.g. following a manual correction of the date in the usual rotation of the fixed teeth of wheel 3) can be correctly multiplied by the number of days that remain in the period shown in the figure, which is always a multiple of the number of days shown in the index of the mobile month 4 (in this case the number of steps that remain in the index of the mobile organ can be multiplied by the number of days correctly indicated in the index of the rotation).

The position of the 9th pendulum is controlled by a drive system 13 based on the position of a first cam 15 and a second cam 17. The first cam 15 is located between the pivot point 9a of the 9th pendulum and the axis of rotation of the mobile 3, and is arranged to rotate with respect to wheel 4. The shape of the first pendulum represents the first 12-month cycle, and thus has upper radius 15a parts representing the odd 29-day months, and lower radius 15b parts representing the even 30-day months.

The second cam 17 is located between pivot point 9a of the 9th pendulum and the periphery of wheel 4, and is also arranged to pivot relative to wheel 4. The shape of the second cam 17 represents the second 30-year cycle, which determines the number of days in the twelfth month. The shape of this cam 17 extends inward, and has upper radius parts 17a, which represent the twelfth months at 29 days, and lower radius parts 17b, which represent the twelfth months at 30 days.

This kind of cams is often called programming cams , because their shape determines the number of days indicated in a month, and is therefore used to program the sequence indicated by mechanism 1.

The cams 15, 17 are supported and driven in rotation relative to wheel 4 by means of an indexing system 19, which is schematically shown in Figures 1 to 3, and ensures that the angular position of each cam 15, 17 relative to wheel 4 is correctly indexed for the indicated date. As represented by the arrows, the indexing system 19 is driven by wheel 4, and drives both cams 15, 17 by means of an appropriate transmission system, such as a gear, Maltese cross, star or any other suitable system.

The operating system 13 includes a first lever 21 carrying a 21a palpation, with the first lever being pivoted on wheel 4 to a pivot point 21b by a spring (not shown). The first lever 21 also carries a plotted 21c-shaped buttress arranged to lean against a side of the swing 9 to bring the swing 9 to its active position (Figure 2). However, said first lever 21 could also work directly with said swing 9 without the use of a plot. Similarly, the first swing 9 could have a plot and the first lever 21 might not.

The first palpation device 21a follows the first cam 15 so that when the first palpation device 21a comes into contact with a portion of the lower 15b radius of the latter (Figure 1), plot 21c does not bring the swing 9 into its active position, and the retractable teeth 11 are in their recessed position, the second drive organ 7b cannot interact with the retractable teeth 11, and a 30-day cycle will therefore be displayed.

However, when the first palpation organ 21a is in contact with a portion of the upper radius 15a of the first cam (Figure 2), plot 21c brings the swing 9 and retractable teeth 11 into their active positions.

At the twelfth month, the first palpeur 21a is in notch 15c, and therefore plot 21c is away from the pendulum 9.

In order to feel the second cam 17, a second lever 23 is also pivoted on wheel 4 at a pivot point 23b, and is in kinematic linkage with the first lever 21 by means of complementary toothed segments 21d, 23d carried by each lever 21, 23. The second lever 23 has a second palper 23a, which is intended to come into contact with the second cam 17, at least during the twelfth month. If the twelfth month is 30 days, the second palper 23a is in contact with a part of the lower radius of the second cam 17, and the actuating device 13 adopts the configuration shown in Figure 1, except that the first palper 21a is actually facing the notch 15.

In the case of the twelfth month with 29 days, the second palper 23a is in front of a part of the upper radius 17a of the second cam 17, as shown in Figure 3. The first palper 21a being in front of notch 15c, it can therefore rotate further towards the axis of rotation of the first cam 15 than in the other positions of the first cam 15. The second palper 23a is therefore free to come into contact with, and take up position against, the upper radius 17a of the second cam 17, which rotates the second swing 23 clockwise (compared to the view of Figures 1 to 3).This rotation is transmitted to an additional drive motor 25 pivoted on wheel 4 and consisting of an additional drive motor 25a arranged to control the swing 9 and a gear motor 25b which is in kinematic connection with the second palpator 23a by means of a transmission lever 24. In the illustrated case, the gear motor 24 also has two gear sectors, even rack sectors, on either side of the gear motor 25b and with a complementary gear sector which includes the second lever 23.

It goes without saying that all kinds of kinematic links between levers 21, 23, 24 and the additional actuating motor 25 are possible, for example, plots cooperating with grooves, a belt or the like.

The mechanism is a generally binary logic system, which has the following transfer table: - What?

Came 1	Came 2	Bascule 9
0 (rayon inférieur)	0 (rayon inférieur)	0 (escamotée ; 30 jours)
0	1 (rayon supérieur)	0
1 (rayon supérieur)	0	1 (active ; 29 jours)
1	1	1 (active ; 29 jours)
X (encoche)	0	0
X	1	1 (active ; 29 jours)

It is clear that cam 1 has priority in this logic, and that only when the first palpation 21a is in front of notch 15c can cam 2 influence the position of the swing 9.

To avoid conflicts between the various components of mechanism 1, they are placed in appropriate planes so that they can overlap each other if necessary. For example, in Figure 1 the transmission lever 24 is overlapped by the first cam 15 which is therefore in another plane.

Figure 4 shows the schematic operation of mechanism 1 as described in the invention. The drive motor 7 drives wheel 4 and, if necessary, the removable teeth 11 at about midnight. If the removable teeth 11 are in their active position and are therefore driven by the second drive organ 7b, the force exerted on the swing drive wheel 4 one step further.

As wheel 4 is in kinematic linkage with the indexing system 19, each change in the angular position of the 3 month mobile changes the state of the indexing system, which changes the position of the first cam 15 and the second cam 17 so that they are correctly indexed relative to wheel 4 for the displayed date.

Figures 5 to 8 illustrate a second mode of implementation of a Muslim calendar mechanism 1 which applies the same principle as in Figures 1 to 3. These figures illustrate mechanism 1 from both sides, including the upper (Fig. 5 and 6) and lower (Fig. 7 and 8) sides, and from perspective (Fig. 5 and 7) and plane (Fig. 6 and 8) views, over a 30-day month. In these figures, the driving motive 7 has not been represented, but may be identical to that shown in Figures 1 to 3 or any other appropriate form.

This mode of manufacture differs mainly from the first in the positioning of the second cam 17 and the components of the actuation system 13.

As can be seen in Figures 5 and 6, the arrangement of the 9th swing, the first cam, the first palper, the 21a and the 21c are substantially unchanged.

However, the first lever 21 is curved so that its rack 21d engages directly with the toothed sector 25b of the additional actuator 25. Therefore, the intermediate levers 23 and 24 of the first embodiment have been removed.

The second cam 17 is on the opposite side of wheel 4, so on the opposite side of the first cam 15, and is located centrally, extending outwards. The second palpation pin 23a is a solidary pin of the first lever 21, which extends through an opening 4a made in wheel 4 so that the second cam 17 can be palpated.

Despite these structural changes, the principle of operation of the mechanism remains unchanged.

Figures 9 to 11 illustrate the same principle of operation as described above, but applied to the processing of the month of February of the Gregorian calendar. This system being more complicated than those described above, some assembly elements (axes, pins, etc.) have not been illustrated. Furthermore, the representation is highly schematic in order to make its operation more clearly visible, and the elements dealing with the leap days of the 31st and 30th of the month have been represented separately from those dealing with the leap day of the 29th of the month, on different figures.

Figure 9 shows the elements for the leap from the 31st day of the month in 30-day months and from each month of February, and the leap from the 30th day of the month to the end of each month.

In this embodiment, the wheel 4 of the month 1 mobile has 31 teeth (or alternatively an integer multiple of 31 teeth) which cooperates with a first drive organ 7a of the month 7 mobile and, in its standard operation, rotates clockwise in the view of Figure 9 at a rate of one turn per month.A second additional swing 29 is also pivoted on wheel 4 (its axis having also been removed from the figure), and also features two teeth that are one step off in the upward direction from those of the first additional swing 27, and which are positioned so that they can interact with yet another additional swing 7d located in yet another plane on the drive mobile.In addition, in the illustrated design, the drive organs are arranged in pairs, 180° offset, so that the drive unit makes one and a half turns per day.

The operation of these swings arising from a single 12-month cycle, mobile 3 has a first additional cam 31 which is followed by a palpation 27a of the first additional cam 27 in order to bring this cam to its active position at the end of the months of 28, 29 or 30 days. This additional cam 31 therefore has five protrusions corresponding to the months of less than 31 days. A second additional cam 33, in rotation with the first additional cam 31, is also followed by a palpation 29a of the second additional cam 28 in order to bring this cam into its active position each February, and to this end this additional cam 31 presents a protrusion corresponding to the month of February.

The indexing system 19 provides the angular relationship between the additional cams 31, 33 and wheel 4, by providing a rotational speed ratio of 11/12 or 13/12 of the additional cams 31, 33 with respect to wheel 4, depending on the relative rotational direction desired between these components.

Figures 10 and 11 illustrate the elements relating to February.The arrangement illustrated represents a modification of the system of Figures 5 to 8, and therefore only the differences with the way these latter figures are made will be described in detail here, the elements having the same reference signs performing the same functions, mutatis mutandis.

The first cam 15, the swing 9 (whose axis of rotation 9a has not been illustrated), and the drive system 13 components shown in Figure 10 are superimposed on the additional cams 27, 29 and 31, 33 so that the teeth 11 of the swing 9 can interact with the second drive organ 7b of the drive mobility 7.

The first cam 15 has 48 sectors representing the first cycle of 4 years/48 months, most of which have the same lower radius, 15b (months other than February). The three parts of the upper 15a radius are bumps representing the months of February that are always non-leap years and that bring the 9 swing into its active position in order to jump on the 29th of the month, and a notch 15c represents those of a year that could possibly be leap years (and therefore have 29 days) according to the Gregorian calendar (i.e. every year divisible by 4).

As in the embodiment of Figures 5 to 8, this notch delegates control of the swing 9 to at least a second cam 17, located on the opposite side of the wheel 4. In this case, the mechanism has not only a second cam 17, but also a second additional cam 18 coaxial to the second. These two cams are felt in parallel by the second palper 23a. - In the embodiment shown, the second cam 17 has twenty sectors, three of which have notches, and the second additional cam 18 has five sectors, one of which has a notch.

If we look at Figure 11, we see the second cam 17, which for example completes a 400-year cycle in relation to wheel 4, and the second additional cam 18, which completes a 20-year cycle in relation to the same wheel. Alternatively, for example, the second cam 17, can also complete a 80-year cycle, and the second additional cam 18, can complete a 400-year cycle. A single second cam 17, with 400 sectors, is indeed very difficult to make given the size of such a mechanism, and it is for this reason that the logical combination AND of two cams 17, 18 was chosen.

Therefore, if a notch of the second cam 17 and a notch of the second additional cam 18 are located below the second cam 23a (which is the case for every year divisible by 100 but not by 400), the latter falls into the combined notch (provided that the 21a notch, which is on the opposite side of wheel 4, is above notch 15c), and the first lever 21 pivots counterclockwise as seen in Fig. 10. Its rake 21d therefore commands the additional drive cam 25a to bring the 11 escapable teeth into their active position, and the 29th day of the month is configured for the years 1700, 1800, 1900, but not so for 1600, 2000 etc. For every other month of the year, February is displayed in at least one of the 17 and 18 positions and therefore the second cam is not in active, and the second and 29th teeth are not in active.

This system is also fully reversible and maintains its indexation during a reverse correction by means of the drive train.

However, the method illustrated is not exhaustive, and depending on the arrangement, size and nature of the cams 17, 18 drive means, any other appropriate speed ratio between them may be considered and is covered by the present invention, provided that the teeth 11 of the swing 9 are properly positioned when passing in front of the drive mobility 7. The important thing is that during the months of February in leap years (i.e. when the palper 21a has the possibility of falling into notch 15c) and when the teeth 11 are close to the drive mobility 7, cams 17 and 18 are correctly positioned.

In all embodiments, it is also possible to provide for a display device for any day of the week, which can be associated with the drive mobile 7.

Although the invention has been described by reference to a few particular embodiments, modifications are possible without going beyond the scope of the invention as defined by the claims. In particular, it should be noted that the same principle can also be applied to a Gregorian, Western annual or Julian, Chinese, Hebrew or similar calendar.

Claims

Calendar mechanism (1) for a timepiece, said calendar mechanism (1) being adapted to indicate information having a period varying according to at least a first cycle and a second cycle, said mechanism (1) comprising:
- a month-wheel (3) comprising a wheel (4) having a number of fixed teeth (5), said number being chosen on the basis of the maximum period of the information to be displayed, characterized in that the wheel (3) further comprises a control-lever (9) arranged to move between an inactive position and an active position and being provided with at least one retractable tooth (11),
and in that said mechanism (1) comprises:
- a drive-wheel (7) comprising a first driving organ (7a) arranged to engage with said fixed teeth (5) and a second driving organ (7b) angularly offset relative to the first driving organ (7a) and arranged to interact with said retractable tooth (11) when said lever (9) is in its active position;

- a first cam (15) representing the variations of said period according to the first cycle;

- at least one second cam (17) representing the variations of said period according to the second cycle;

- an indexing system (19) kinematically linked to said wheel (4), with said first cam (15) and with said second cam (17) and adapted to index each of said cams (15, 17) relative to said wheel (9) in function of said cycles;

- an actuating system (13) for said lever (9), the actuating system (13) comprising a first feeler-spindle (21a) intended to come into contact with the first cam (15) and a second feeler-spindle (23a) intended to come into contact with the second cam (17), said feeler-spindles (21a, 23a) being kinematically linked with each other and the actuating system (13) being arranged to move said lever (9) from its inactive position to its active position under the control of each of said cams (15, 17) .
Calendar mechanism (1) according to Claim 1, wherein said first cam (15) and said second cam (17) are each coaxial to said wheel (4) and are carried by this latter.
Calendar mechanism (1) according to any of Claims 1 and 2, wherein each of said cams (15, 17) is located on the same side of said wheel (4).
Calendar mechanism (1) according to any of Claims 1 and 2, wherein one of said cams (15, 17) is located on a first side of said wheel (4), and the other one of said cams (17, 15) is located on a second side of said wheel (4) .
Calendar mechanism (1) according to Claim 4, wherein the second feeler-spindle (23a) extends through an opening (4a) in said wheel (4) .
Calendar mechanism (1) according to any of the preceding claims, wherein the actuating system (13) comprises a first lever (21) provided with said first feeler-spindle (21a), the first lever (21) also comprising an abutment (21c) intended to come into contact with said lever (9) in order to move said lever to its active position under the control of said first cam (15).
Calendar mechanism (1) according to the preceding claim, wherein the second feeler-spindle (23a) is carried by the first lever (21).
Calendar mechanism (1) according to Claim 6, wherein the actuating system comprises a second lever (23) kinematically linked with said first lever (21), said second lever (23) carrying said second feeler-spindle (23a) .
Calendar mechanism (1) according to any of Claims 6 to 8, wherein the actuating system (13) comprises an additional actuating wheel (25) kinematically linked with at least said first lever (21) and arranged to move said lever (9) to its active position under the control of said second cam (17).
Calendar mechanism (1) according to Claim 9, wherein the additional actuating wheel (25) is pivoted relative to said wheel (4) and comprises an additional actuating cam (25a) intended to press against said lever (9) under the control of said second cam (17).
Calendar mechanism (1) according to any of the preceding claims, wherein said first cam (15) has a form (15, 15b) representing the number of days in a month varying according to a first cycle, and said second cam (17) has a form (17a, 17b) representing the number of days in at least one particular month that varies according to a second cycle, and wherein said first cam (15) comprises a notch (15c) representing at least one month, the number of days of which is determined according to said second cycle.
Calendar mechanism (1) according to Claim 11, wherein the first cycle comprises twelve months, the form of said first cam (15) representing the number of days from the first to the eleventh month varying according to the first twelve month cycle, the notch (15c) corresponding to the twelfth month, and wherein the second cycle comprises thirty years, the form of said second cam (17) representing the number of days of the twelfth month varying on the second thirty year cycle.
Calendar mechanism (1) according to Claim 11, wherein the first cycle comprises four years, the form of said first cam (15) representing the number of days in February varying according to the first four year cycle, the notch (15c) corresponding to the optionally leap year month of February, and wherein the second cycle comprises 400 years, the form of said at least one second cam (17) representing the number of days in February of the years divisible by four.
Calendar mechanism (1) according to Claim 13, further comprising a second additional cam (18) superposed on said second cam (17), the combination of the second cam (17) and of the second additional cam (18) defining a 400 year cycle.
Calendar mechanism (1) according to Claim 14, wherein said second feeler-spindle (23a) is arranged to feel the second cam (17) and the second additional cam (18) in parallel.
Calendar mechanism (1) according to any of the preceding claims, wherein said lever (9) carries at least two retractable teeth (11) having the same separation as two adjacent fixed teeth (5).
Calendar mechanism (1) according to any of the preceding claims, further comprising display a device for the day of the week, which is preferably associated with the drive wheel (7).