Leap year indication mechanism for a clock movement having a perpetual calendar indication

Abstract

To provide a leap year display mechanism that is relatively simple in design and minimizes power consumption.SOLUTION: A leap year display mechanism 10 for a timepiece movement having a perpetual calendar display, comprises: a drive element 21 connected to a month wheel set 20 that rotates by one step per month; a transmission star 30 intended to be mounted on a structure of the timepiece movement, the transmission star 30 arranged along a stroke of the drive element 21 so as to rotate when the month wheel set 20 completes one full rotation; and a leap year display part 40 connected to the transmission star 30 via a reduction gear train 32, the leap year display part 40 rotated by one step per rotation of the month wheel set 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the field of timepieces, and in particular to timepieces with a perpetual calendar display.

[0002] More particularly, the present invention relates to a leap year indication mechanism for a timepiece movement having a perpetual calendar indication. [Background technology]

[0003] The perpetual calendar mechanism is a well-known horological complication that allows the display of the date by adapting to the length of the months automatically, i.e. without the need for manual intervention, and taking into account leap years in particular.

[0004] In some watches, the perpetual calendar mechanism is connected to a display which indicates whether the current year is a leap year or a normal year.

[0005] These mechanisms are complex to manufacture and assemble, and typically consume a lot of power. Summary of the Invention

[0006] The present invention overcomes the above-mentioned shortcomings by providing a leap year indication solution that is relatively simple in design and minimizes power consumption.

[0007] The mechanism according to the invention is particularly suitable for roller displays.

[0008] To this end, the present invention comprises: a drive element connected to a moon wheel set which is rotated by one step per month; a transmission star intended to be attached to a structure of the clock movement and arranged along the stroke of the drive element so as to rotate when the moon wheel set completes one full revolution; A leap year indicator connected to the transmission star via a reduction gear train so that it rotates one step with each revolution of the moon wheel set; The present invention relates to a leap year indication mechanism for a clock movement having a perpetual calendar indication including

[0009] In particular embodiments, the invention may further comprise one or more of the following features, which must be considered individually or according to any technically possible combination:

[0010] In a particular embodiment, the drive element takes the form of a finger that is eccentrically attached to the lunar wheel set by a recessed type mechanical connection.

[0011] In a particular embodiment, the transmission star has four teeth.

[0012] In certain embodiments, the leap year indicator includes an indicator representing the current year type, including leap and normal years.

[0013] In certain embodiments, the leap year indicator takes the form of a roller that includes an indicator wall on which an index representing the current year type is displayed.

[0014] In a particular embodiment, the leap year indicator includes an annular bearing surface via which the leap year indicator is mounted to the reduction gear train, the annular bearing surface being connected to the indicator wall by an end wall.

[0015] In a particular embodiment, the leap year indicator includes a mechanism for adjusting its angular position, the mechanism being formed by a radial lug attached to an annular bearing surface, which connects the annular bearing surface to the end wall, the radial lug including a threaded hole cooperating with a screw that engages a curved, elongated slot in the end wall.

[0016] In a particular embodiment, the reduction gear train includes a first wheel rigidly mounted coaxially to the transmission star for rotation therewith, and a second wheel rigidly mounted coaxially to the leap year indicator for rotation therewith.

[0017] In a particular embodiment, the reduction gear train is configured such that one step of the leap year indicator corresponds to one eighth of its rotation. [Brief description of the drawings]

[0018] Further features and advantages of the invention will appear on reading the following detailed description, given by way of non-limiting example and with reference to the attached drawings, in which:

[0019] [Figure 1] 1 shows a partially exploded perspective view of a leap year display mechanism of a clock movement having a perpetual calendar display according to a preferred embodiment of the present invention. [Diagram 2] 2 shows a cross-sectional view of a characteristic part of the display mechanism in FIG. 1. [Diagram 3] 3 shows a cross-sectional view taken along the cutting plane AA in FIG. 2. [Figure 4] 3 shows a cross-sectional view taken along the cutting plane BB in FIG. 2.

[0020] It should be noted that for purposes of clarity, the drawings have not necessarily been drawn to scale. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] As can be seen in the exploded view of FIG. 1, the present invention relates to a leap year indication mechanism 10 for a timepiece movement having a perpetual calendar indication.

[0022] The leap year indicator mechanism 10 comprises a moon wheel set 20 which rotates by one step per month. A drive element 21 is connected to the moon wheel set 20. In a preferred embodiment of the invention, the drive element 21 advantageously takes the form of a finger and is attached to the moon wheel set 20 by a mechanical connection of the recessed type, i.e. without any degrees of freedom.

[0023] The drive element 21 is advantageously mounted eccentrically with respect to the axis of rotation of the lunar wheel set 20, as shown in Figure 1, and is intended to rotate the transmission star 30 by one step for each revolution made by the lunar wheel set 20. In detail, the transmission star 30 is mounted so that it can rotate with respect to a structure, such as a plate or a bridge, of the clock movement (not shown in the drawings), preferably by means of a support structure 31 shown in Figures 2 and 3.

[0024] The transmission star 30 is connected to a leap year display 40 via a reduction gear train 32. With each revolution of the month wheel set 20, the leap year display 40 is rotated by one step.

[0025] In the embodiment shown in the drawings, the invention is advantageously applied to a roller type date indicator. Alternatively, the invention can be adapted to any type of date indicator without any design difficulties for the person skilled in the art. In particular, the invention can be adapted to a disk type date indicator.

[0026] As can be seen in figures 1 and 2, the lunar wheel set 20 takes the form of a roller comprising a number of flaps 22 displaying the names of the months. These flaps 22 are arranged to be supported by a frame which can rotate relative to a support structure 31, which in a preferred embodiment of the invention can rotate relative to said mobile structure. In detail, the lunar wheel set 20 comprises six flaps 22, each flap displaying two different months and arranged to complete half a rotation for each full rotation of the frame. The frame is rotated to complete one full rotation every six months by a date mechanism known per se to those skilled in the art. Such a lunar wheel set 20 is described in EP 3267266.

[0027] The frame is formed, for example, by a shaft 23, each of whose two ends is rigidly connected to a flange 24 for co-rotation, as can be seen in the exploded view in Fig. 1 or in the cross-section in Fig. 2. In detail, each of the two ends of the shaft 23 is arranged to pivot in a support structure 31 intended to be attached to the structure of the clock movement. The drive element 21 is preferably mounted on one of these flanges 24 so as to pivot about the longitudinal axis of the shaft 23 when the moon wheel set 20 is rotating.

[0028] The support structure 31 may include a circularly extending groove 310 whose centre is aligned with the axis of rotation of the axle 23. The drive element 21 may be housed inside said groove 310 throughout its entire stroke. This feature allows the dimensions of the display mechanism according to the invention to be reduced.

[0029] Advantageously, as shown in Figure 1, the reduction gear train 32 includes a first wheel 320 rigidly mounted coaxially to the transmission star 30 for rotation therewith, and a second wheel 321 rigidly mounted to the leap year indicator 40 for rotation therewith. As can be seen in the cross-sectional view of Figure 2, the second wheel 321 includes a tubular portion 323 by which the second wheel 321 is rotatably arranged on the support structure 31. In a preferred embodiment of the invention, the leap year indicator 40 has a degree of rotational mobility relative to the support structure 31 by cooperating with the tubular portion 323 of the second wheel 321, as will be described in more detail below.

[0030] Therefore, as shown in Figures 1, 2 and 4, the reduction gear train 32 preferably has only two wheels.

[0031] Furthermore, the rotation axis of the drive element 21, the rotation axis of the transmission star 30, the rotation axes of the first wheel 320 and the second wheel 321 of the reduction gear train 32, and the rotation axis of the leap year indicator 40 are parallel to one another.

[0032] Advantageously, the reduction gear train 32 includes a holding star 322 rigidly connected to and rotating with the second wheel 321. The holding star 322 is arranged to cooperate with the jumper 33 to hold the second wheel 321, and thus the leap year indicator 40, at predetermined discrete angular positions.

[0033] Preferably, as shown in the exploded view of FIG. 1 and in the cross-sectional view of FIG. 4, jumper 33 is configured to be held against retaining star 322 by jumper spring 34.

[0034] Alternatively, the jumper 33 may itself be formed by an elastic strip, which may be arranged against the retaining star 322 by deformation of the elastic strip. In such a case, the leap year indicator mechanism 10 does not include a separate jumper spring.

[0035] In a preferred embodiment of the present invention, the reduction gear train 32 is configured such that one step of the leap year indicator 40 corresponds to one eighth of a revolution. In particular, since the drive element 21 rotates the transmission star 30 one quarter of a revolution, the reduction gear train 32 is dimensioned to produce a one-half reduction ratio with the retaining star 322 including eight teeth. Since the month wheel set 20 makes two complete revolutions per year, the leap year indicator 40 rotates at a rate of one complete revolution every four years.

[0036] Leap year indicator 40 carries an indicia 41 which represents the current year. Indicia 41 includes leap years and normal years. In particular, indicia 41 of leap year indicator 40 represents a series of eight characters which are intended to be visible one after the other at a rate where two consecutive characters are displayed per year. In the preferred embodiment, these characters are formed by the sequence 1, 1, 2, 2, 3, 3, B, B.

[0037] The indicator 41 may be visible through a window made in an exterior part (not shown in the drawings) that covers the leap year indicator 40 .

[0038] Preferably, the leap year indicator 40 takes the form of a roller including a cylindrical indicator wall 42. On the cylindrical indicator wall 42, an index 41 is displayed that indicates the type of the current year. Furthermore, the leap year indicator 40 includes an annular bearing surface 43, by which the leap year indicator 40 is attached, without any degree of freedom, to the second wheel 321 of the reduction gear train 32, in particular to the tubular part 323, as shown in FIG. 2. More particularly, the annular bearing surface 43 is pressed into or joined to the tubular part 323. Advantageously, the tubular part 323 may include any other element, such as a flute or a key for stopping the rotation. The annular bearing surface 43 is connected to the indicator wall 42 by an end wall 44, as shown in the embodiment visible in FIG. 2.

[0039] Advantageously, leap year indicator 40 may include a mechanism for adjusting its angular position. More specifically, as shown diagrammatically in FIG. 2, this adjustment mechanism may be formed by a radial lug 45 attached to an annular bearing surface 43, which is connected by this lug 45 to the end wall 44 and thus to the indicator wall 42. In particular, radial lug 45 includes a threaded hole intended to cooperate with a screw 46. Screw 46 is engaged in an oblong hole 47 made in end wall 44, which extends in a curvilinear direction. This curvilinear direction is defined by the arc of a circle whose centre is aligned with the axis of rotation of leap year indicator 40.

[0040] That is, when the screw 46 is loosened, the indicator wall 42 can move relative to the annular bearing surface 43. This movement corresponds to an angular displacement defined by the travel of the screw 46 between the ends of the slot 47. When the screw 46 is tightened, the leap year indicator 40 is held in place.

[0041] A number of adjustment mechanisms are envisioned which correspond to those described above, namely the radial lugs 45, screws 46, and slots 47 shown in FIG.

[0042] Advantageously, the annular bearing surface 43, and thus the second wheel 321 and the leap year indicator 40, are prevented from translational movement relative to the support structure 31 by the central screw 48, which is intended to cooperate with a thread made in said support structure 31. In particular, as can be seen in the cross-sectional view of Figure 2, the tubular portion 323 is inserted between two axial bankings formed by the head of the central screw 48 and the support structure 31, thereby eliminating any translational movement of the second wheel 321 and the leap year indicator 40.

[0043] In general, it should be noted that the implementations and embodiments considered above are described as non-limiting examples, and thus other alternative implementations and embodiments may be envisioned.

Claims

1. A leap year indication mechanism (10) for a timepiece movement having a perpetual calendar indication, comprising: a drive element (21) connected to a lunar wheel set (20) which is rotated by one step per month; a transmission star (30) intended to be attached to a structure of the timepiece movement and aligned along the stroke of the drive element (21) so as to rotate when the moon wheel set (20) completes one full rotation; a leap year indicator (40) connected to said transmission star (30) via a reduction gear train (32), said leap year indicator (40) being rotated by one step for each complete rotation of said month wheel set (20); Including, 1. A display mechanism, characterized in that the leap year indicator (40) takes the form of a roller including an indicator wall (42) on which an index (41) indicating the type of the current year, including leap year and normal year, is displayed.

2. 2. The display mechanism according to claim 1, wherein the drive element (21) is eccentrically mounted on the lunar wheel set (20) by means of a recessed type mechanical connection.

3. 3. An indicator mechanism according to claim 1 or 2, wherein the transmission star (30) has four teeth.

4. The leap year indicator (40) includes an annular bearing surface (43) and is attached to the reduction gear train (32) by the annular bearing surface (43); 2. An indicator mechanism according to claim 1, wherein the annular bearing surface (43) is connected to the indicator wall (42) by an end wall (44).

5. The leap year display unit (40) includes a mechanism for adjusting its own angular position, The mechanism is formed by radial lugs (45) attached to the annular bearing surface (43), the radial lugs (45) connecting the annular bearing surface (43) to the end wall (44); 5. An indication mechanism according to claim 4, wherein the radial lug (45) includes a threaded hole cooperating with a screw (46) which is engaged with an elongated hole (47) made in the end wall (44) and extending in a curvilinear direction about the axis of rotation of the leap year indicator (40).

6. 2. The display mechanism of claim 1, wherein the reduction gear train (32) includes a first wheel (320) rigidly mounted coaxially to the transmission star (30) and rotating therewith, and a second wheel (321) rigidly mounted coaxially to the leap year display portion (40) and rotating therewith.

7. 2. The display mechanism of claim 1, wherein the reduction gear train (32) is configured such that one step of the leap year indicator (40) corresponds to one eighth of a revolution.

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