CH688171B5 - additional mechanism of astronomical representation for timepieces. - Google Patents

Description

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CH 688 171G A3

Description

The present invention relates to an additional astronomical representation mechanism for timepieces comprising a first device intended to provide a representation of the appearance of the moon as a function of time at a predetermined geographic location, combined with a second device intended to produce a visualization of the convolution movement of the moon, and a representation of the celestial vault animated by a rotational movement.

Timepieces are known which are provided with such additional mechanisms. Application EP 0 107 177 describes a mechanism reproducing in a window of a watch the movement of the moon relative to the earth and the evolution of its appearance during its different phases.

The utility model DE-U 8 610 323 reveals a pendulum with a device showing the appearance of the moon as a function of time combined with a visualization of the convolution movement of the moon and a representation of the sky on a rotating disc . This representation of the sky is provided on the same disc as the openings indicating the convolution of the moon. The position of the latter relative to the stars is therefore fixed, which does not correspond to reality.

Application WO 91/11756 refers to a device for representing the appearance of the moon combined with the convolution movement of the latter, without representation of the sky.

Application DE-A 3 602 976 describes a device intended to provide a representation of the appearance of the moon and of the convolution movement of the moon and the sun. For this purpose, a moon disc includes an opening through which a wheel carrying a representation of the moon is visible. The moon disc also includes a representation of the sun and stars. The position of the stars is therefore fixed relative to that of the moon, which does not give a correct astronomical representation.

The object of the present invention is to remedy the aforementioned drawbacks and to create an additional mechanism making it possible to visualize the appearance and the convolutional motion of the moon in relative motion with respect to the representation of the celestial vault also in rotation.

The invention is characterized for this purpose by the fact that the additional mechanism comprises a third device arranged so as to provide a representation of the celestial vault visible at said geographical location, animated by a rotation movement in the counterclockwise direction which is independent of the convolution movement of the moon, so that the position and appearance of the latter on the representation of the sky is changed as a function of time.

We obtain by these characteristics a faithful representation of a certain number of astronomical phenomena and in particular of the relative movements of rotation of the celestial vault and the moon, as well as the evolution of the aspect of the latter on the sky in rotational movement.

According to a preferred embodiment, the mechanism is characterized in that the second device comprises a first disc rotatably mounted above a base plate and carrying said first device, and in that the third device comprises a second at least partially transparent disc rotatably mounted above the first disc and provided with the representation of the sky, each of the discs being connected by means of at least one declutching member to a driving member.

These characteristics allow a precise, simple and reliable construction, as well as a very faithful astronomical representation.

Advantageously, the second device is arranged so as to produce a movement of rotation of the representation of the moon in a counterclockwise direction around a center and so as to indicate the moment of the passage of the moon at the meridian M of said geographical location, the speed of rotation of this circular movement being substantially equal to 0.9961 revolution in 24 hours.

This gives a more complete indication of the movement of the moon relative to the geographic location of the observer.

According to a preferred embodiment, the third device is arranged so that the speed of the rotational movement of the representation of the sky is substantially equal to 1.00274 turn in 24 hours.

The timepiece thus offers a precise animated representation of the sky visible at said geographic location.

According to a favorable embodiment, it comprises a drive shaft disposed in a decentralized manner relative to the center, the declutching members being constituted by two declutching wheels engaged in friction on this drive shaft and cooperating with the periphery of said first and second discs.

The drive shaft can be kinematically connected to the barrel of the timepiece.

It is thus possible to obtain a construction of a very reduced height, of a small overall size and comprising a reduced number of parts.

Favorably, the mechanism comprises a glass covering the second disc provided with at least one indication delimiting the visible field of the celestial vault at said geographical location.

According to an advantageous embodiment, the first device comprises a moon phase wheel mounted under the first disc opposite an opening of this disc having a diameter corresponding to the diameter of the representation of the full moon, the moon phase wheel being provided at its upper surface at least one geometric figure making it possible to reproduce the appearance of the moon phases in

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CH 688 171G A3

function of time, this moon phase wheel being driven in rotation by means of a planetary gear mounted under the first disc and of which a gear meshes with a fixed pinion disposed on the center of rotation of the first disc.

By these characteristics, one obtains a very natural representation of the aspect of the moon varying during a lunar cycle.

The mechanism favorably comprises an adjustment and correction device comprising two crowns made integral in rotation with a movable bezel, the crowns being connected to the first, respectively second, disc by means of clutch members arranged so that it there is no mechanical connection between the crowns and the discs when the movable bezel is not rotated, and so that the movable bezel is mechanically connected to the first, respectively to the second disc, when the movable bezel is rotated according to a first, respectively a second, direction of rotation, the declutching member, respectively the declutching members, then interrupting the drive of the first, respectively of the second disc, by the driving member.

This construction allows precise and simple adjustment and adjustment of all the movements of the additional mechanism.

Other advantages bring together the characteristics expressed in the dependent claims and the description setting out the invention below in more detail with the aid of drawings which schematically represent, by way of example, an embodiment.

Fig. 1 is a view of a pocket watch comprising an additional mechanism of astronomical representation in accordance with the invention.

Fig. 2 schematically represents a view of the additional mechanism in exploded form.

Figs. 3a and 3b show a cross-sectional view of this additional mechanism.

Fig. 4 illustrates the device for training and correcting the movement of the sky in plan view.

Fig. 5 is a sectional view through the device for driving and correcting the movement of the sky.

Fig. 6 illustrates the device for training and correcting the movement of the moon in plan view.

Fig. 7 is a sectional view through the device for driving and correcting the movement of the moon.

Fig. 8 is a plan view of the device making it possible to obtain the representation of the lunar phases.

The timepiece illustrated in fig. 1 consists of a pocket watch 1 with a winding and time-setting element 2, a cover 3 hinged to the case 4 of the watch and capable of covering the rear face 5 of the watch. This rear face 5 is intended to provide an astronomical representation and is in particular arranged so as to show the celestial vault with the stars visible at a determined geographical location of the terrestrial globe, for example Geneva. The representation 10 of this celestial vault is applied to a disc of the sky 11 rotating concentrically around the center 7 of the movement of the watch corresponding to the pole star.

Offset on the lower surface of the watch glass 8, an opening line 9 makes it possible to determine the stars visible in the sky at this geographical location, for example Geneva, at any time of the day or night. The sky disc 11 with its representation of the celestial vault also determines the time of passage to the meridian M of a predetermined star, for example the star SIRIUS 12.

The sky disc 11 described counterclockwise 1.00 2748 763 turn in 24 hours; the theoretical speed value being 1.0 027 3781 2 turns in 24 hours, an error of +5 min results. 43.7 s per year.

The rear face 5 is also arranged so as to provide a representation of the moon 15 moving concentrically at the center 7 of the movement by indicating its time of passage at the meridian M, therefore its position in the sky. The state of the moon, namely the lunar phase, is also represented at every moment of the day or night.

The counterclockwise rotation of the moon mechanism is 0.9 961 413 637 revolutions in 24 hours. The theoretical value being 0.9 961 368 073 turn in 24 hours, it results in an error of +2 min. 34.5 s per year.

The representation of the lunar phase is obtained by a planetary gear device with two satellite wheels and presents a period between two identical states of the moon, namely between two lunar months, of 29 days 12 hours 44 min. 50s. The theoretical value is 29 days 12 hours 44 min. 2.8 s, an error of +47.2 s per lunation results.

A mobile telescope 17 makes it possible to carry out the adjustments and corrections either of the angular position of the celestial vault by rotation counterclockwise of this telescope 17, or of the position of the moon and of its phase by clockwise rotation of this bezel.

Figs. 2 to 8 allow to better understand the construction of the additional mechanism at the base of this astronomical representation. With reference to fig. 2 to 8, this mechanism comprises a base plate 20 screwed onto a bridge 21 of the watch movement. A moon disc 22 is rotatably mounted by means of a bearing 19 on a central axis 23 located at the center 7 of the movement of the watch. The mechanism has six rollers 24 mounted freely rotating on cylin4

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CH 688 171G A3

dres pivots 25 arranged on the base plate at the periphery of the moon disc 22. The transparent sky disc 11 is provided with a representation of the celestial vault and arranged in a rotating manner above the moon disc 22 and supported at its periphery by the rollers 24. The watch glass 8 with its opening 9 is fixed to a fixed bezel 26 and the latter is held in place by screws 27 on the base plate 20. Finally, the movable bezel 17 is mounted and maintained on the fixed bezel 26 thanks to a spring ring 28. A sliding ring 29 facilitates the rotation of the movable bezel 17 during corrections.

The moon disc 22 has a complex structure. It is surmounted by a background disc from the sky

30 of blue color having a circular opening 31 corresponding to the diameter of the representation of the full moon. The moon disc 22 has an opening 32 communicating with the opening

31 of identical size (see fig. 2 and 3a).

A recess 34 provided in the lower part of the moon disc 22 (see fig. 3a) is closed by a bridge 35. The planetary gear device 36 intended to produce the representation of the lunar phase is housed in this recess 34. This device is shown in plan in fig. 8 and comprises a moon phase wheel 38 of yellow color on which are transferred two blue circles 39 diametrically opposite with respect to its central axis 40 and having a diameter substantially identical to the diameter of the circular opening 31 provided in the bottom disc of the sky 30. This moon phase wheel 38 is rotated by means of a planetary train 42 comprising two satellite wheels 44 and 49. A moon phase return 43 rotates around an axis 45 and engages d on the one hand with a fixed pinion 46 which comes in one piece with the central axis 23 and on the other hand with a pinion 47 mounted freely rotating on the axis 40. The moon phase wheel 38 and the pinion 47 are not therefore not united. The first satellite wheel 44 meshes with this pinion 47 and rotates around an axis 48. It is integral with a second satellite wheel 49 which it meshes with the moon phase wheel 38.

Thus, during the rotation of the moon disc 22, the entire planetary gear device 36 is driven in rotation about the axis 23 and the moon phase wheel 38 is thus also driven in rotation.

By cooperating with the opening 31, this moon phase wheel 38 produces an exact representation of the state of the moon at any time for a predetermined geographic location.

The drive of the moon discs 22 and the sky discs 11 is explained with reference to FIGS. 3b, 4 and 6. A drive member 50, such as the barrel of the watch movement, sets in motion a drive wheel 51 secured to a drive shaft 52 on which a first clutch release wheel of the clutch is engaged in friction. sky 53 cooperating with the sky disc 11 and a second moon release wheel 54 cooperating with the moon disc 22.

Two superimposed correction crowns 56 and 57 are rotatably mounted on the base plate 20 and made integral in rotation with the movable bezel 17 by means of a pin 58 cooperating with openings 59, 60 provided in the crowns 56, 57.

The upper correction crown 56 meshes with a sky disengaging return gear 62, the axis 63 of which is slidably mounted in slots 64 of the base plate 20 and of the fixed bezel 26 (FIGS. 4 and 5). . When it is desired to correct the position of the sky disc 11, the movable telescope 17 is rotated counterclockwise. The latter drives the upper correction crown 56 which moves the pinion 62 in the direction of the sky disengaging wheel 53 and meshes with the latter to rotate the sky disc 11 counterclockwise. During the correction, the sky declutching wheel 53 disengages on the drive shaft 52. Outside the correction period, the pinion 62 is not meshed with the wheel 53, thus preventing the movable telescope 17 from being driven by the motor 50.

With reference to fig. 6 and 7, the lower ring gear 57 meshes with a moon disengaging return gear 70, the axis 71 of which is slidably mounted in slots 72 of the base plate 20 and of the fixed bezel 26. An intermediate gear 73 permanently meshes with the moon disengaging wheel 54. When correcting the position of the moon disc, the movable bezel 17 and the crown 57 are turned clockwise and the pinion 70 is moved in the direction of the pinion intermediate 73 to drive the latter, the moon release wheel 54 and the moon disc 22, which then rotates counterclockwise.

During the correction, the moon clutch release wheel 54 disengages by friction on the drive shaft 52. Outside the correction period, the moon clutch release gear 70 is not meshed with the intermediate gear 73 to prevent the movable telescope 17 from being rotated by the shaft 52.

An adequate choice of the teeth of the different gears provides an excellent chronological representation of the lunar phases and the position of the stars.

For this purpose, the sky declutching wheel 53 comprises a number Z53 of 38 teeth and the sky disc 11 a number Zn of 321 teeth. With this choice of teeth, the theoretical speed of revolution of the sky disc 11 is close to the real speed of naked revolution;

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1.002748763 round / 24 hours where

Nso = 3.2 revolutions / 24 hours corresponding to the speed of rotation of the barrel 50;

Z50 = 90 = number of teeth of the toothing of the barrel 50;

Z51 = 34 = number of teeth of the drive wheel 51;

Z53 = 38 = number of teeth of the overhead clutch wheel 53;

Z11 = 321 = number of teeth of the sky disc 11.

With these gear ratios the imprecision is +0.941 s / 24 hours, i.e. +5 min. 43.7 s / year.

The real speed of revolution ri22 of the moon disc 22 is given by the formula:

n50

'50

'53

3.2

90

38

not

1 1 =

'51

'1 1

34. 321

n ^ Q. Z50 - 254 3.2. 90. 43

n22 = = = 0.996141 3637

Z51. Z22 34. 377 tour / 24 hours where

Z54 = 43 = number of teeth of the moon clutch wheel 54;

Z22 = 377 = number of teeth of the moon disc 22.

With these gear ratios the imprecision is +0.423 s / 24 hours, i.e. + 2min. 34.5 s / year.

The speed of rotation n38 of the moon phase wheel 38 is determined by the teeth of the wheels of the planetary gear device 36 and is given by the formula:

n22 - Z47 - Z49 0.9661413637 .8.10

38 = = = 0.016931 2834

Z44. Z3Q 55. 83 turns / 24 hours corresponding for a lunation at

0.5 / 0.0169312834 =

29.53113393 days =

29 days 12h 44 min. 50 s where

Z47 = 8 = number of teeth of pinion 47;

Z44 = 55 = number of teeth of the first satellite wheel 44;

Z49 = 10 = number of teeth of the second satellite wheel 49;

Z38 = 83 = number of teeth of the moon phase wheel 38;

The number of teeth of the fixed pinion 46 is also 8 and the number of teeth of the moon phase return 43 is 60. An inaccuracy of + 47.2 s / lunation is obtained.

To correct the angular position of the sky disc 11, you have to do ns6 = 0.8 turn with the telescope 17 counterclockwise to obtain a correction of 1 turn with the sky disc, because n- | 1. Z-j 1 1.321 n56 = = = 0.8 turn

Z56 392

or

n56 = 0.8 = number of turns of the correction crown 56, therefore of the moving telescope 17; Z56 = 392 = number of teeth of the upper correction crown 56;

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Likewise, to correct the angular position of the moon disc 22, you must do n57 = 0.8 turn with the movable telescope 17 clockwise to make a correction of 1 turn with the moon disc, because n22 • z22 1 • 377

= = = 0.80 turn

Z57 460

or

n57 = 0.8 = number of turns of the lower correction crown 57, therefore of the moving telescope 17; Z57 = 460 = number of teeth of the lower correction crown 57.

In practice, to update the sky disc, it is necessary to record on an astronomical calendar supplied with the watch, the time of passage through the meridian of the predetermined geographic location (eg Geneva) of the chosen star, for example SIRIUS. A first triangular index 80 is transferred onto the sky disc 11 at its periphery opposite the chosen star. The index is then adjusted to the meridian mark "M" of the fixed bezel by turning the movable bezel 17 counterclockwise. The time difference between the reading time taken and the time when setting is then calculated. The fixed bezel 26 is provided with a graduation divided into 24 parts corresponding to 24 hours. Each part includes 12 subdivisions of 5 minutes. Knowing said time difference, the index 80 is set to the scale corresponding to the time of adjustment. If the adjustment time is after the recorded passage time, the index will be advanced counterclockwise by the time difference and if the adjustment time is before the detected passage time, the index will be advanced 24 hours minus the calculated time difference.

To regulate the position of the moon in the sky, it is necessary to note in the astronomical calendar the hour of passage of the moon at the meridian of the predetermined geographical place. A second triangular index 81 is transferred onto the background disc of the sky 30 fixed to the moon disc 22 on the spoke connecting the center of the disc 30 to the center of the opening 31. This second index 81 is set to the meridian mark "M »Of the fixed telescope 17. The difference between the recorded time of passage of the moon and the time of adjustment is then calculated and the second index 81 is set to the scale corresponding to the time of adjustment. If the setting time is after the passing time recorded, the second index 82 will be advanced counterclockwise by this difference; otherwise, it will be advanced 24 hours minus the calculated time difference.

To update the lunar phase or the state of the moon, the movable telescope 17 must be rotated as many times as necessary to reveal the full moon on the background disc of the sky 22 while replacing the second index 81 as well. before. Then the day of the full moon is noted in the astronomical calendar and the number of days separating this date from the day of the watch setting is calculated. The index is then made to have a number of turns equivalent to the number of days calculated previously. After these adjustment operations, the additional mechanism of astronomical representation is perfectly adjusted for at least one year, the angular inaccuracies due to the limited number of teeth of the gears being very small.

It is understood that the embodiment described above is in no way limiting and that it can receive any desirable modifications within the framework as defined by claim 1. In particular, the additional mechanism may be integrated in other types of timepieces, for example in wristwatches or table clocks. Instead of being mounted on the rear face of the timepiece, the mechanism could constitute the front face and be combined with the time indication. Instead of being centered, it could be arranged eccentrically. One could also provide an additional mechanism comprising a representation of the celestial vaults of two hemispheres N and S arranged on both sides of a pocket watch or side by side on a clock.

The number of gears, their ratios, the declutching and clutching devices, as well as the adjustment and correction device could, of course, be designed differently. The drive member 50 may be of any mechanical, electrical or other nature.

Claims (14)

Claims 1. Additional astronomical representation mechanism for timepieces comprising a first device (31 to 49) intended to provide a representation of the appearance of the moon as a function of time at a predetermined geographic location, combined with a second device (22 , 50, 54) intended to produce a visualization of the convolution movement of the moon, and a representation of the celestial vault (10) animated by a rotational movement, characterized in that it comprises a third device (11, 50, 53) arranged so as to provide a representation of the celestial vault (10) visible at said geographical location animated by a rotation movement in the counterclockwise direction which is independent of the 7 5 10 15 20 25 30 35 40 45 50 55 60 65 OH 688 171G A3 convolution movement of the moon (15) so that the position and appearance of the latter on the representation of the sky is changed as a function of time. 2. Mechanism according to claim 1, characterized in that the second device comprises a first disc (22) rotatably mounted above a base plate (20) and carrying said first device (31 to 49), and in that the third device comprises a second disc (11) at least partially transparent, rotatably mounted above the first disc (22) and provided with the representation of the sky, each of the discs being connected by the 'Intermediate of at least one declutching member (53, 54) to a driving member (50). 3. Mechanism according to claim 1 or 2, characterized in that the second device (22, 50, 54) is arranged so as to produce a movement of rotation of the representation of the moon counterclockwise around a center (7) and so as to indicate the moment of the passage of the moon at the meridian M of said geographical location, the speed of rotation of this circular movement being substantially equal to 0.9961 revolutions in 24 hours. 4. Mechanism according to one of claims 1 to 3, characterized in that the third device (11, 50, 53) is arranged so that the speed of the rotational movement of the representation of the celestial vault is substantially equal to 1.00274 turn in 24 hours. 5. Mechanism according to one of claims 1 to 4, characterized in that the first device (31 to 49) is arranged so that the period between two identical states of the appearance of the moon is substantially equal to 29 days 12 hours and 44 minutes. 6. Mechanism according to claims 2 and 5, characterized in that it comprises a drive shaft (52) disposed decentralized relative to the center (7), the declutching members being constituted by two clutch release wheels (53 , 54) engaged in friction on this drive shaft and cooperating with the periphery of said first and second discs (22, 11). 7. Mechanism according to claim 6, characterized in that the drive shaft (52) is intended to be kinematically connected to a barrel (50) of the timepiece. 8. Mechanism according to claim 5, characterized in that it comprises a crystal (8) covering the second disc (11) provided with at least one indication (9) delimiting the visible field of the celestial vault at said geographical location. 9. Mechanism according to claim 5, characterized in that the first device comprises a moon phase wheel (38) mounted under the first disc (22) opposite an opening (31) of this disc having a diameter corresponding to the diameter of the representation of the full moon, the moon phase wheel (38) being provided on its upper surface with at least one geometric figure making it possible to reproduce the appearance of the moon phases as a function of time, this phase wheel moon (38) being rotated by means of a planetary gear (42) mounted under the first disc (22) and of which a gear (43) meshes with a fixed pinion (46) disposed on the center of rotation of the first disc (22). 10. Mechanism according to one of claims 6 and 7, characterized in that it comprises an adjustment and correction device comprising two crowns (56, 57) made integral in rotation with a movable bezel (17), the crowns ( 56, 57) being connected to the first, respectively second disc (11, 22) by means of clutch members (62, 70) arranged so that there is no mechanical connection between the crowns ( 56, 57) and the discs when the movable bezel (17) is not rotated, and so that the movable bezel (17) is mechanically connected to the first (11), respectively to the second disc (22), when the movable bezel (17) is rotated along a first, respectively a second, direction of rotation, the declutching member (53, 54), respectively the declutching members, then interrupting the drive of the first, respectively of the second disc by the driving member (50). 11. Mechanism according to claim 10, characterized in that the clutch members are constituted by pinions (62, 70) meshing with one or the other of the two crowns (56, 57) and comprising axes capable of '' be moved transversely so as to establish or interrupt a mechanical connection by gear between one or the other of the rings and the first or the second disc (11, 22). 12. Mechanism according to claim 7, characterized in that the barrel (50) to which it is intended to be connected comprises a gear with 90 teeth, the mechanism comprising a drive wheel (51) with 34 teeth integral with the shaft drive (52), a first disengaging wheel (53) with 38 teeth meshing with a gear secured to the second disc (11) comprising 321 teeth, and a second disengaging wheel (54) with 43 teeth meshing with a gear secured of the first disc (22) having 377 teeth, the speed of rotation of the barrel (50) being 3.2 revolutions in 24 hours. 13. Mechanism according to claims 9 and 12, characterized in that the fixed pinion (46) comprises 8 teeth, the gear (43) of the planetary gear (42) comprising 60 teeth and being connected by a second pinion (47) to 8 teeth to a first satellite wheel (44) with 55 concentric teeth and integral with a second satellite wheel (49) with 10 teeth which meshes with the moon phase wheel (38) comprising 83 teeth, the latter comprising on its upper surface two diametrically opposite circles (39) of dark color on a yellow background. 14. Pocket watch comprising an additional mechanism according to one of the preceding claims, characterized in that it constitutes its rear part (5). 8