Islamic hijiri calendar

Abstract

The invention relates to an Islamic Hijiri calendar for a mechanical clockwork movement, comprising a 30-position date indicator arranged to be driven by a date-driving mechanism and to engage with a large rocker (7). A month control mechanism is arranged to differentiate between the months with 29 days and those with 30 days. A year control mechanism is arranged to differentiate between an abundant year and a common year. During a common year, a large rocker (7) is arranged to engage with a date star (9) to move two teeth of the date star (9) in order to move from the 29th of a month to the 1st of the following month, the large rocker (7) resting on a month cam (4).

Description

[0001] The present invention relates to a mechanical Hijri calendar, particularly for use in analog timepieces. More specifically, it relates to a perpetual Hijri calendar that can be fitted into the movement of a wristwatch, a clock, or a pocket watch.

[0002] The Hijri calendar is a widely used modern lunar calendar. This calendar is characterized by years of 12 lunar months, which are shorter than solar years. Each Hijri year has approximately 354 days, or sometimes 355 days, consisting of 12 months of 29 and 30 days. Odd-numbered months have 30 days and even-numbered months have 29, meaning the year begins with a 30-day month and ends with a 29- or 30-day month. In reality, a Hijri year is slightly longer than 354 days. To compensate for this difference, the last month of some years in a 30-year correction cycle has 30 days instead of 29. This 30-year cycle includes 19 years of 354 days, called common years, and 11 years of 355 days, called abundant years.

[0003] EP0606576 on behalf of the applicant describes a Hijri calendar for an analog clock movement, comprising a date indicator with 30 positions advancing by one position to successively display the numbers 1, 2... 29, 30, 1, 2.... The calendar includes a first mechanism whose function is to drive, from a moving part of the movement, at the end of each day, the date indicator by a single step, a second mechanism cooperating with said first mechanism and whose function is to drive, at the end of even months, the date indicator by two successive steps to move it from the 29th to the 1st of the following month in a short interval of time.The calendar also includes a third mechanism cooperating with the other two mechanisms and whose function is to temporarily neutralize the action of the second mechanism at the end of abundant years, defined by a 30-year correction cycle, so that the date indicator displays 30 on the last day of the 12th and last month of said years.

[0004] WO2015062839, on behalf of the plaintiff, describes a Hijri calendar for a clockwork movement comprising a 30-position date indicator that advances in one-position increments to successively display the numbers 1, 2... 29, 30, 1, 2...The calendar includes a first date-driving mechanism whose function is to drive, from a wheel of the movement, at the end of each day, the date indicator by a single step, a second month-length correction mechanism arranged to cooperate with said first date-driving mechanism in order to drive, at the end of months of 29 days, the date indicator by two successive steps to move it from the 29th of one month to the 1st of the following month, the second month-length correction mechanism comprising a month cam having six bumps and six hollows, each hollow defining a position of the month cam corresponding to a 29-day month and each bump defining a position of the month cam corresponding to a 30-day month.The calendar also includes a third blocking mechanism that works in conjunction with the other two mechanisms and whose function is to temporarily neutralize the action of the second mechanism, which corrects the length of months, at the end of the twelfth month of abundant years, defined by a 30-year correction cycle. The third blocking mechanism is arranged so that, during the last month of said abundant years, it locks the month cam in a position corresponding to a 30-day month, so that the date indicator displays 30 on the last day of the twelfth and final month of said abundant years.

[0005] The present invention proposes a simplified Hijri calendar which displays the dates respecting the alternation of months of 29 and 30 days in a year, and the succession of common years and abundant years on one of the 30-year correction cycles.

[0006] According to the invention, a Hijri calendar for a mechanical clock movement comprises a date indicator with 30 positions that advances by one position to successively and cyclically display at the end of each day the numbers from 1 to 30, 1, 2...said date indicator being arranged to be driven by a date-driving mechanism and to cooperate with a large rocker, a month control mechanism arranged to distinguish months with 29 days from months with 30 days, the month control mechanism comprising a month star cooperating with a month cam comprising twelve positions, a year control mechanism arranged to distinguish an abundant year from a common year, the year control mechanism comprising a year sector arranged so as to skip a year star coupled to a year cam comprising flattened teeth and having a resting surface on each flattened tooth on which a finger rests in each abundant year, the finger resting on a hollow part between two flattened teeth to indicate a common year.The large rocker is arranged to cooperate directly during a common year with a day star to move two teeth of the day star to move from the 29th to the 1st of the following month, the large rocker resting on the month cam, the finger being mounted on the month cam which is concentric with the year cam.

[0007] Thanks to the present invention, the arrangement of the large rocker makes it possible to simplify the movement by avoiding the need to integrate a locking mechanism as is known from the prior art.

[0008] Indeed, in the prior art mechanisms, it is necessary to integrate a locking mechanism that neutralizes the action of a mechanism correcting the length of the months. For example, a locking lever pivoting around an axis should be integrated, having at one end a feeler applied against the year cam, and at the other end a locking finger. The locking lever is arranged so that, during a lean year, the feeler is positioned on a bump of the year cam, and the locking finger is abutted against a lug provided on the eleventh bump of the month cam, thus blocking and disengaging the month cam and preventing its pivoting when transitioning to the twelfth month of the lean year. In common years, the locking lever is positioned so that the locking finger does not impede the pivoting of the month cam when transitioning to the twelfth month of the common year.

[0009] Such a mechanism as described in the prior art is functional but more complicated to build and therefore to maintain.

[0010] In one form of execution, the large lever is arranged to cooperate with the finger so as to make a tooth pop off the star of days for the transition from the 30th to the 1st of the month during an abundant year.

[0011] According to this same form of execution, the finger is mounted pivoting around an axis and having at one end a beak arranged to receive a point of the large seesaw in each abundant year.

[0012] In one form of execution, the cam of the years has eleven irregularly distributed flattened teeth.

[0013] According to this same form of execution, a sector of the years is arranged to make a star of the years jump one step every year according to a 30-year cycle.

[0014] The features of the invention will become clearer upon reading the description of several embodiments given solely by way of example and not limiting the scope of the invention, with reference to the schematic figures, in which: There figure 1 represents a top view of a Hijri calendar mechanism during a common year; The figure 2 represents a top view of a Hijri calendar mechanism during an abundant year; The figure 3 represents a part of a watch movement comprising a Hijri calendar mechanism according to the present invention; The figure 4 represents a top view of a mechanism indicating on a watch dial the presence of a month with a duration of 29 days; The figure 5 represents a top view of a mechanism indicating on a watch dial the presence of a month with a duration of 30 days; and The figure 6 represents a top view of a mechanism indicating during the last month of the year the presence of a month with a duration of 30 days.

[0015] As illustrated in the figure 1 A Hijri calendar for a mechanical clock movement includes a 30-position date indicator advancing in one-position increments to successively and cyclically display at the end of each day the numbers from 1 to 30, 1, 2... said date indicator being arranged to be driven by a date-driving mechanism and to cooperate with a large rocker 7. The calendar also includes a month 1, 4 control mechanism arranged to distinguish between months with 29 days and months with 30 days, the month control mechanism having a month 1 star cooperating with a month 4 cam comprising twelve positions.The calendar also includes a year control mechanism arranged to distinguish an abundant year from a common year, the year control mechanism having a year sector 10 arranged to make a year star 5 coupled to a year cam 6 having flattened teeth 12 and having a resting surface 13 jump by one step (see . figure 2 ) on each flattened tooth 12 on which a finger 8 rests for each abundant year, the finger 8 resting on a hollow part 14 between two flattened teeth 12 to indicate a common year.

[0016] In a common year, the large seesaw 7 is arranged to cooperate with a star of days 9, to move two teeth of the star of days 9 to move from the 29th to the 1st of the following month, the large seesaw 7 relying on the cam of months 4.

[0017] In this example, the star of month 1, via links 2 and 3, positions the cam of month 4. A sector of year 10 advances the star of year 5 by one step per year according to a thirty-year cycle. During the 12th month of the common year, finger 8 positions itself, in its lower position, within the hollow of the cam of year 6, outside the range of the point 7a of the large rocker 7. The large rocker 7 advances two teeth of the star of days 9, moving from the 29th to the 1st of the following month.

[0018] The day star 9 has twenty-nine flat teeth 17 and one pointed tooth 18 indicating the transition to a new cycle of days in a month.

[0019] As illustrated in the figure 2 , during an abundant year, the large seesaw 7 is arranged to cooperate with the finger 8 so as to make a tooth jump the star of days 9 for the passage from the 30th to the 1st of the month.

[0020] The position of the month 4 cam indicates that the year is bountiful. In this configuration, finger 8 is located on the top of the year 6 cam. The large rocker 7 no longer rests on the month 4 cam, but on finger 8, causing the day 9 star to jump one tooth, for the transition from the 30th to the 1st of the following month.

[0021] In each of these examples, the 6-year-old cam has eleven flattened teeth 12 irregularly distributed.

[0022] The finger 8 is mounted pivoting around an axis 15 and has at one end a beak 16 arranged to receive a point 7b of the large rocker 7 in each abundant year.

[0023] As illustrated in the figure 4 , a rocker 19 probes the month cam 4 to determine whether the current month is a month of 29 days or 30 days, depending on the twelve positions represented on said month cam.

[0024] For this purpose, a disc 20, thanks to two distinct indications, here two different colors, indicates to the bearer, through an opening 21 of the day window 22, whether the month has a duration of 29 or 30 days.

[0025] The rocker 19 is arranged to cooperate with a toothed section of the disc 20, which pivots on the axis of the day star 9 and allows the 29 / 30 indication to be displayed through the day window. The rocker 19 moves the disc 20 from a first position where it indicates a month of 29 days to a second position where it indicates a month of 30 days, the rocker 19 bearing against the month cam 4.

[0026] In this example, the 20 dot is positioned to indicate a month with a duration of 29 days.

[0027] In the example illustrated in the figure 5 , the rocker 19 probes the month 4 cam positioned to determine that the current month is a month of a duration of 30 days.

[0028] Thus, the 20 disc is positioned to indicate to the bearer, through the opening 21 of the day window 22, that the current month is a month of 30 days.

[0029] In the example illustrated in the figure 6 , during the last month of the year, it is finger 8 which positions rocker 19 to indicate a month with a duration of 30 days.

[0030] In a bountiful year, finger 8 is located on the top of the year 6 cam. Rocker 19 no longer rests on the month 4 cam, but on finger 8 and allows the display of the month of a duration of 30 days through the day window.

[0031] Such a calendar can be incorporated into a timepiece, such as a wristwatch or a clock.

Claims

1. Islamic Hijri calendar for a mechanical clockwork movement, comprising: - a 30-position date indicator which advances by steps of one position to successively and cyclically display, at the end of each day, the numbers from 1 to 30, 1, 2 ..., the date indicator being arranged to be driven by a date-driving mechanism and to cooperate with a large rocker (7); - a month control mechanism (1, 4) arranged to differentiate between the months with 29 days and months with 30 days, the month control mechanism comprising a month star (1) cooperating with a month cam (4) comprising twelve positions; and - a year control mechanism which is arranged to differentiate between an abundant year and a common year, the year control mechanism comprising a year sector (10) arranged to cause a one-step skip by a year star (5) coupled to a year cam (6) comprising flattened teeth (12) and having a rest surface (13) on each flattened tooth (12) on which a finger (8) rests in each abundant year, the finger (8) resting on a hollow portion (14) between two flattened teeth (12) in order to indicate a common year, the large rocker (7) being arranged to rest on the month cam (4), characterized in that the finger (8) is mounted on the month cam (4) which is concentric with the year can (6) and in that the large rocker (7) is arranged to cooperate directly with a date star (9) during a common year in order to move forward by two teeth of the date star (9) to move forward from the 29th to the 1st of the following month.

2. Calendar according to Claim 1, wherein, in an abundant year, the large rocker (7) is arranged to cooperate with the finger (8) so as to cause the date star (9) to skip one tooth in order to move forward from the 30th to the 1st of the month.

3. Calendar according to either Claim 1 or Claim 2, wherein the year cam (6) comprises eleven irregularly distributed flattened teeth (12).

4. Calendar according to any one of the preceding claims, wherein the finger (8) is pivotably mounted about an axis (15) and comprises at one end a spout (16) configured to receive a tip (7b) of the large rocker (7) in each abundant year.

5. Calendar according to any one of the preceding claims, wherein a year sector (10) is arranged to make a year star (5) skip by one step per year, according to a 30-year cycle.

6. Calendar according to any one of the preceding claims, wherein a rocker (19) is arranged to cooperate with a toothing pivoting on the axis of the date star (9) in order to move a pad (20) from a first position where it indicates a 29-day month to a second position where it indicates a 30-day month, the rocker (19) resting on the month cam (4).

7. Calendar according to Claim 6, wherein the pad (20), as a result of two distinct indications, is arranged to indicate, through an opening (21) in a clock face (22), whether the month has a duration of 29 days or 30 days.

8. Timepiece comprising an Islamic Hijri calendar according to any one of Claims 1 to 7.

9. Timepiece according to Claim 8 in the form of a wristwatch.

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