Patent Application
20190146414
The invention concerns the field of horology. It concerns, more specifically, a mechanism, commonly called an astronomical complication, which allows the display of both:
The astronomical features of the moon have been known for a long time and are notably described by James Ferguson in “Astronomy explained upon Sir Isaac Newton's principles”, the fifth edition of which was published in 1772.
The mean value of the lunar day (separating two crossings of the meridian) is 24 hours, 50 minutes and 28.328 seconds.
The solar day to lunar day ratio is thus:
As for the mean value of the lunation (the duration separating two full moons), this is 29 days, 12 hours, 44 minutes and 2.8 seconds.
Claiming to be inspired by Ferguson, E. Cloux, in his Horology course given at the Technical College of the Vallee de Joux (Switzerland) in 1949, drew a lunar day and moon phase display mechanism, in superposition on the solar day (with a mean value of 24 hours).
The mechanism drawn by E-Cloux, represented in
This ingenious mechanism makes it possible to display the moon crossing the meridian in 24 hours, 50 minutes, 31.58 seconds, and a lunation in 29.5 days.
It is seen that these are approximations of the mean lunar day and the mean lunation, imposed by the choice of gear ratio:
24 h>59/57=24 h 50 min 31.58 s
However, the mechanism drawn by E. Cloux has no member for making corrections to the display that are made necessary either by deviations resulting from the aforecited approximations, or, quite simply, by the mechanism stopping once the power source is depleted (usually a mainspring in mechanical watches, which, if not rewound will unwind completely).
Consequently, it is an object of the invention to propose a solution which makes it possible to correct, in a simple and reliable manner, the lunar day and lunation in the mechanism presented above.
To achieve the aforecited object, there is proposed a timepiece mechanism for displaying the lunar day and the moon phase, which includes:
As a result of this double correction system, which acts by using two distinct kinematic chains, it is possible to correct, in a simple and reliable manner, the lunar day display and the moon phase display.
According to a main embodiment, the lunar day display correction system and the moon phase correction system include a joint correction device for activating the lunar day display and, without activating the lunar day display, the moon phase. This joint correction device includes a sliding pinion which alone forms the first and second drive elements, said sliding pinion being able to adopt two adjustment positions, namely:
The correction device advantageously includes a carrier pinion which meshes with the sliding pinion and at least one small connecting rod which joins the axes of rotation of the sliding pinion and of the carrier pinion.
The first rotating element includes, for example, a toothed wheel which extends perpendicularly to the main axis, integral with a pipe which extends along the main axis. The second rotating element then includes an auxiliary wheel which extends perpendicularly to the main axis, integral with a sleeve which is friction fitted onto the pipe of the first rotating element.
The friction connection between the second rotating element and the first rotating element is advantageously achieved by indenting, which for example takes the form of a one-off deformation of the internal diameter of the tube of the second rotating element, in order to ensure friction on the conical slot made in the pipe of the first element.
According to a preferred embodiment, the moon wheel set includes two superposed integral wheels, namely:
According to a particular embodiment:
The central wheel preferably carries a crown toothing meshed with the moon pinion; further, the central wheel is advantageously fitted onto the pipe of the first rotating element.
The moon bearing is preferably mounted on the central wheel, for example, fitted onto the latter with the insertion of a smooth bearing.
The transmission wheel advantageously includes a pair of diametrically opposite jumper springs.
Finally, the star wheel typically has 29 or 30 teeth, or, in a preferred variant, 59 teeth.
Other features and advantages of the invention will appear in light of the following description of one embodiment, made with reference to the annexed drawings, in which:
Watch 1 includes, housed inside case 2, a timepiece movement which includes a bottom plate 7 and, mounted on the plate, at least one timepiece mechanism 8 designed to ensure display of the lunar day and moon phase.
As we will see, mechanism 8 is also designed to ensure display of the minutes and hour of the mean solar day but such a display is optional and could be provided by a separate mechanism.
Mechanism 8 belongs to the family of ‘astronomical’ complications; it is organised around a main axis A1 perpendicular to the general plane of plate 7.
The moon is displayed as a body, in the form of a sphere 9 driven in a double movement:
According to an embodiment illustrated in
As seen in
Motion-work 13 is driven in rotation by a drive device (not represented) including an energy source and a transmission. As astronomical complications are usually associated with mechanical watches, it is preferable for the energy source to be a mainspring associated with a balance/balance spring regulator. Nevertheless, if the energy source were a battery associated with a quartz resonator it would not be outside the scope of the invention.
As already mentioned, mechanism 8 is designed to display the minutes and the hour of the mean solar day.
For the minute display, mechanism 8 includes a cannon pinion 17, rotatably mounted about main axis A1 and provided with a centre pinion 18 meshing with large wheel 14, and with a tube 19 fitted (with the possibility of rotation) onto arbor 10 of centre wheel set 11. Cannon pinion 17 carries a minute hand 20 which, as illustrated in
For the hour display, mechanism 8 includes an hour wheel set 21, rotatably mounted about main axis A1 and provided with an hour wheel 22 meshing with medium wheel 15, and a hollow shaft 23 fitted (with the possibility of rotation) onto tube 19 of cannon pinion 17. Hour wheel set 21 carries an hour hand 24 which, as illustrated in
Hour wheel 22 is provided with a peripheral toothing typically having a number of teeth Z5=64, such that the gear reduction ratio (i.e. the ratio of rotational speeds) between hour wheel 22 and centre pinion 18 is:
Consequently, hour wheel set 21 makes one revolution about main axis A1 in 12 hours.
For the lunar day and moon phase display, mechanism 8 includes, firstly, a first rotating element 25 rotatably mounted about main axis A1 and meshing with motion-work 13.
More specifically, in the example illustrated, in particular, in
According to one embodiment illustrated in
In the illustrated example, pipe 27 is tiered, and includes a lower tier 28, integral with solar wheel 26, and an upper tier 29, of smaller diameter than that of tier 28. The lower tier and the upper tier are separated by a shoulder 30.
Solar wheel 26 meshes with small wheel 16 of motion-work 13. This solar wheel is provided with a peripheral toothing typically having a number of teeth Z6=64, such that the gear reduction ratio between first rotating element 25 and hour wheel set 21 is:
Consequently, first rotating element 25 makes one revolution about main axis A1 in 24 hours. In other words, the first rotating element can be used to measure the mean solar day. It can also be employed to display the mean solar day. Thus, in the illustrated embodiment (cf.
Mechanism 8 includes, secondly, a moon bearing 32 rotatably mounted about main axis A1. The moon bearing is provided with a meridian wheel 33. The moon bearing is also provided with a moon cover 34, fixed to the meridian wheel to rotate integrally therewith. In a variant, the meridian wheel and the moon cover form a one-piece part.
Meridian wheel 33 is provided with a peripheral toothing typically having a number of teeth Z7=57.
As seen in
Mechanism 8 includes, thirdly, a sphere 9 representing the moon, rotatably mounted relative to moon bearing 32 about a radial axis A3 perpendicular to main axis A1. Sphere 9 advantageously has two hemispheres of contrasting colours, namely:
Hemispheres 36, 37 can be made distinct by applying paint. However, in a preferred embodiment, the hemispheres are half-spherical calottes made from different materials and assembled to form sphere 9. Thus, dark hemisphere 36 can be made from biotite mica, obsidian or any other dark mineral, while light hemisphere 37 can be made of metal (for example silver or grey gold), or from a light-coloured mineral (for example moonstone).
Further, in the illustrated example, radial axis A3 is formed by a runner 38 that passes through sphere 9 and rotates integrally therewith. At an inner end, the runner is mounted in a sleeve 39 fitted into a hole 40 made in moon bearing 32.
As seen in
Moon pinion 41 is provided with a peripheral toothing typically having a number of teeth Z8=14.
Mechanism 8 includes, fourthly, a second rotating element 42, rotatably mounted about main axis A1. According to an embodiment illustrated in
Second rotating element 42 is mounted on first rotating element 25 with friction at their interface, referenced 45 (the interface is the surface where the first rotating element and the second rotating element make contact).
More precisely, sleeve 44 is friction fitted onto pipe 27 of the first rotating element. Even more precisely, the sleeve is friction fitted onto the lower tier 28 of the pipe. This friction fit is intended to make second rotating element 42 integral (in rotation about main axis A1) with first rotating element 25, while the torque, referenced C1, resulting from various circumferential forces respectively exerted on the first rotating element and on the second rotating element is lower than a friction torque, referenced CF, which determines the maximum adhesion force at interface 45.
In other words:
The friction connection at interface 45 between the second rotating element and the first rotating element can, in practice, be achieved by an indent 46, which takes the form, for example, as illustrated in the detailed inset of
Second rotating element 42 is provided with a star wheel 47. This peripherally formed star wheel 47, is, for example, cut externally in sleeve 44. It includes a series of triangular teeth 48, which are 30 in number here, but could be 29 in number, or even 59 in number (which is the approximate number of half-days in one lunation).
Mechanism 8 includes, fifthly, a central wheel 49, mounted on first rotating element 25 and geared with moon pinion 41. This central wheel advantageously carries a crown toothing 50 (i.e. whose teeth extend parallel to main axis A1) meshed with moon pinion 41. This toothing is, for example, cycloidal and has a number of teeth Z10 equal to the number of teeth Z8 of the moon pinion (namely Z10=14 here).
In the example illustrated in
According to a preferred embodiment illustrated in
Mechanism 8 includes, sixthly, a moon wheel set 52 which rotationally couples, with gear reduction, first rotating element 25 to meridian wheel 33 (and thus to moon bearing 32) to allow the moon bearing to be rotated by first rotating element 25. More precisely, moon wheel set 52 rotationally couples second rotating element 42 (integral in rotation with first rotating element 25 while C1<CF) to the meridian wheel.
Moon wheel set 52 is offset, rotatably mounted about an axis A4 parallel to main axis A1. According to an embodiment illustrated in
Lower wheel 53 is provided with a peripheral toothing typically having a number of teeth Z11=43. Upper wheel 54 is provided with a peripheral toothing typically having a number of teeth Z12=37 teeth. Consequently, the gear reduction ratio, referenced R, of solar wheel 26 to meridian wheel 33 (equal to the rotational speed ratio of moon bearing 32 to first rotating element 25) is:
This gear reduction ratio provides the displayed mean lunar day value, referenced J:
This is an excellent approximation of the real mean lunar day. Indeed, the lunar day displayed shows a loss of only 5/100ths of a second per solar day relative to the real lunar day (i.e. one day of loss every eight years).
The lunar day display is ensured by the circular path (i.e. the revolution) of sphere 9 about main axis A1. The moon crossing the zenith is represented by sphere 9 crossing twelve o'clock.
According to a preferred embodiment, illustrated in dotted lines in
The path of approximately 180° of sphere 9 above bar 55 (from the point of view of the wearer) represents the moon's path in the visible sky (lunar day), while the path of approximately 180° of sphere 9 below the bar represents the moon's path in the non-visible sky (lunar night).
Moon wheel set 52 is advantageously mounted on a bridge 56 which is itself fixed to plate 7. Its axis of rotation A4 is, for example, materialized by a screw in helical engagement with bridge 56.
Mechanism 8 includes, seventhly, a transmission wheel 57 integral with central wheel 49, designed to make the latter rotate integrally with second rotating element 42 during normal operation of mechanism 8, and conversely, to allow rotation of one relative to the other when the display is corrected, in conditions which will be set out below.
Transmission wheel 57 is provided externally with a toothing 58 and internally with at least one jumper spring 59.
According to an embodiment illustrated in
As illustrated in
The (or each) jumper spring 59 is engaged and mesh (via its head 64) with the toothing of star wheel 47. In its position of equilibrium (in the absence of any stress), jumper spring 59 would occupy a position in which head 64 is separated from main axis A1 by a distance smaller than the radius of the star wheel.
In normal operation, the (or each) jumper spring 59 is retained by its head 64 between two adjacent teeth 48 of star wheel 47. Jumper spring 59 is held in this position by its own elastic return force which tends to draw head 64 in the direction of main axis A1.
During normal operation, second rotating element 42, which is integral with first rotating element 25 (and thus driven therewith in rotation) rotates about main axis A1 in the clockwise direction (seen from above). Star wheel 47 consequently exerts on head 64 of the (or of each) jumper spring 59 a stress that causes the latter to butt, which tends to keep head 64 between two adjacent teeth 48 of the star wheel. In these conditions, the second rotating element (with the first rotating element) and transmission wheel 57 (with central wheel 49) are integral in rotation about main axis A1 and rotate together in the clockwise direction about the latter (
Central wheel 49 is made integral with transmission wheel 57, for example by means of feet 65, protruding onto the central wheel, driven into holes made in transmission wheel 57. In a variant, this attachment can be achieved using screws.
During a correction of the moon phase display, a drive torque is applied to transmission wheel 57 to drive it in rotation about main axis A1 (in the anticlockwise direction when seen from above, cf.
Second rotating element 42, friction mounted on first rotating element 25, resists the rotation of transmission wheel 57, and the torque resulting from the various circumferential forces exerted respectively on first rotating element and on transmission wheel 57 is referenced C2.
It is at this point that the elasticity of jumper spring(s) 56 plays a part. Each jumper spring 59 is set—i.e. dimensioned—to:
Jump torque CS is lower than friction torque CF, i.e.:
CS<CF
Consequently, the application of torque C2 alone can never cause second rotating element 42 to slide relative to first rotating element 25. The first and second rotating elements therefore remain integral in rotation (and thus immobile) during a moon phase correction.
During normal operation, central wheel 49 (with crown toothing 50) rotates integrally with the second rotating element (and thus with the first rotating element) at a rate of one complete revolution about main axis A1 in 24 hours.
Given gear reduction ratio R presented above, moon bearing 32 (with sphere 9) makes its own complete revolution more slowly (in 24 hours, 50 minutes and 28.378 seconds), And, given the fact that moon pinion 41 and crown toothing 50 include the same number of teeth (Z8=Z10), sphere 9 is driven slowly in rotation about radial axis A3 (in the clockwise direction when mechanism 8 is observed from the side, in the direction of radial axis A3).
Sphere 9 makes one complete rotation about its axis A3 in a number L of days corresponding to the displayed lunation value, i.e.:
This is an excellent approximation of the real lunation, with a loss of around 7 minutes per month compared to said real lunation (i.e. one day of loss every 17 years).
We have seen that the differences between the displayed lunar day and the real lunar day, on the one hand, and the displayed moon phase and the real moon phase on the other hand, are small. One lunar day correction and one lunation correction would be required after several years of uninterrupted operation of watch 1.
However, users who are diligent enough not to let the power reserve of a mechanical watch become depleted are rare. Thus, corrections required to reset the displays after watch 1 has stopped due to absent-mindedness of the user are more frequent than corrections required to make up losses accumulated by mechanism 8 during uninterrupted operation.
To correct the lunar day display, mechanism 8 is provided with a correction device 66 including a pinion 67 able to mesh with moon wheel set 52 to force rotation of moon bearing 32 about main axis A1 via a first correction train which bypasses transmission wheel 57 and which includes moon wheel set 52 and meridian wheel 33.
To correct the moon phase display, mechanism 8 is provided with a correction device 66 which includes a pinion 67 able to mesh with transmission wheel 57 to force rotation of sphere 9 about radial axis A3 via a second train which includes the transmission wheel, central wheel 49 and moon pinion 41.
Mechanism 8 could have two distinct correction devices to correct the lunar day display and the moon phase display separately. To activate them separately, watch 1 could be provided with two distinct winding mechanisms that could be operated independently of one another by the user (or a watchmaker).
However, in a preferred embodiment illustrated in the drawings, and more particularly in
This correction device 66 includes a sliding pinion 67 able to adopt two adjustment positions, namely:
In the example illustrated in
Carrier pinion 68 is rotatably mounted on bridge 56 about an axis A5 parallel to main axis A1 and advantageously materialized by a screw helically engaged with bridge 56.
Correction device 66 includes a winding mechanism 70 provided with a stem 71 mounted in a sliding pivot arrangement about and along a winding axis A6 perpendicular to main axis A1, and with a crown 72 integral in rotation with stem 71. The stem passes through case middle 3 and the crown is accessible to the user.
According to a particular embodiment illustrated in
Correction device 66 also includes a sliding member 74 provided with a winding pinion 75 (for example with a Breguet toothing) and a sliding pinion 76, mounted in a sliding pivot arrangement about and along winding axis A6, and coupled to winding mechanism 70, for example by a traditional pull out piece and lever mechanism (not represented), between:
Transmission of the rotation of winding mechanism 70 to carrier pinion 68 is advantageously achieved via an intermediate train, which typically includes a first intermediate wheel 77, meshed with sliding pinion 76, and a second intermediate wheel 78, inserted between the first intermediate wheel and the carrier pinion.
Finally, in an embodiment illustrated in particular in
Correction of the lunar day display causes a rotation of sphere 9 about its axis A3 and consequently a change in the moon phase display. This is why correction of the lunar day display must precede correction of the moon phase display.
Prior to any correction, cam 74 must be placed in the correction position, by pulling (in a conventional manner for the user or watchmaker) winding crown 72, which pushes sliding pinion 76 towards first intermediate wheel 77 to place them in mesh.
To correct the lunar day display, winding crown 72 must be rotated in a determined direction which depends on the number of pinions in intermediate train 77, 78. In the embodiment illustrated in
Rotation of winding crown 72 then drives, via intermediate train 77, 78, carrier pinion 68 in the clockwise direction (seen from above), which also tends to pivot connecting rods 69 in the clockwise direction and causes (or maintains) the meshing of sliding pinion 67 with moon wheel set 52.
The clockwise rotation of carrier pinion 68 then successively drives in rotation:
It will be noted that, during the lunar day correction, the resulting torque C2 which is exerted on auxiliary wheel 43 exceeds friction torque CF, such that, while first rotating element 25 remains rotationally immobile about axis A1 (since it is blocked by motion work 13), indent 46 yields and allows the auxiliary wheel to slide relative to pipe 27 at their interface 45.
The rotation of the winding crown 72 is stopped when the angular position of radial axis A3 of sphere 9 about main axis A1 is deemed to be correct, which ends the lunar day display correction.
The moon phase display must then be corrected. To do so, winding crown 72 must be rotated in the opposite direction to the direction followed during correction of the lunar day display. In the example illustrated in
The rotation of winding crown 72 drives, via intermediate train 77, 78, carrier pinion 68 in the anticlockwise direction (seen from above), which also tips connecting rods 69 in the anticlockwise direction until sliding pinion 67 meshes with intermediate phase wheel 73.
As the rotation of winding crown 72 continues, the anticlockwise rotation of carrier pinion 68 successively drives in rotation:
As soon as torque C2 attains jump torque CS (which the user or watchmaker's fingers are quite capable of causing to happen), transmission wheel 57, whose toothing 58 is meshed with intermediate phase wheel 73, is itself driven in rotation in the clockwise direction. All these movements are illustrated by the arrows in
However, jump torque CS is lower than the friction torque CF of second rotating element 42 on first rotating element 25. Consequently, despite the rotation of transmission wheel 57, the second rotating element remains immobile, since it is integral in rotation with the first rotating element, which is locked by motion-work 13.
Consequently, the jumper or jumpers 59 is/are shifted radially and jump from one tooth to the next as transmission wheel 57 rotates, as illustrated in dotted lines in
Central wheel 49, integral in rotation with transmission wheel 57, is driven, with its toothing 50, in rotation about axis A1 in the clockwise direction. As moon bearing 32 remains immobile, this rotation of the central wheel causes, via moon pinion 41 with which it meshes, rotation of sphere 9 about its radial axis A3, in the clockwise direction (seen from along axis A3).
In a first variant, by adding, for example, an additional wheel set to the moon phase correction train between the transmission wheel and the sliding pinion, the sphere then rotates in the anticlockwise direction, which corresponds to its direction of rotation in normal operation. In a second variant, assuming that, during a lunar day correction, sphere 9 is driven in a movement of revolution about main axis A1 in the clockwise direction, then the additional wheel set can be inserted in the kinematic chain of correction device 66. By way of alternative, in a third variant, one wheel set is removed from the kinematic chain of correction device 66. Finally, it is also possible to obtain a moon phase correction by reversing the relative position of the moon wheel set and the transmission wheel, the moon phase correction would then be made by rotating the crown in the clockwise direction, whereas the lunar day correction would be made by rotating the crown in the anticlockwise direction.
When star wheel 47 has 29 or 30 teeth, each jump of jumper spring(s) 59 from one tooth to the other corresponds to a correction of one day. When the star wheel has 59 teeth, each jump of the jumper spring(s) from one tooth to the other corresponds to a half-day correction. The wearer or watchmaker is informed of this correction (of one day or respectively a half-day) by the click sound that accompanies the jump of the jumper spring(s).
Once corrections to the lunar day display and the moon phase display are completed, the wearer pushes winding crown 72 back in, which moves cam 74 in translation, uncoupling sliding pinion 76 from first intermediate wheel 77.
During normal operation of watch 1, it is not inconvenient for sliding pinion 67 to remain meshed with moon wheel set 52 (as illustrated in
It is seen that the correction device 66 presented above makes it possible, in a simple, efficient, precise and reliable manner, to correct the lunar day and moon phase in mechanism 8. For the wearer or the watchmaker, the direction of rotation alone determines the correction applied.
| Number | Date | Country | Kind |
|---|---|---|---|
| 17201110.8 | Nov 2017 | EP | regional |
