EP0959392A1 - Device for indicating the time of different time zones - Google Patents

Abstract

Watch device has an extra ring (60) that rotates around an axis (X0, X0') placed behind the dial (18) and having at least two sets of hands (22, 24) apparent through the face. Control means (70) cause rotation of the ring and means (86) reset the ring. Both are connected to the gear chain (36). The latter has a first mobile (50) with a common axis to that of the ring (60). Rotation of ring (60) to an angle ensures the rotation of corresponding hands (22, 24) for two different time zones.

Description

The invention relates to a device for indicating the time, such as that a watch, comprising a case provided with a background and a dial, analog time display means, motor means, and a train gears for transmitting the movement of the motor means to said display means.

We already know time indication devices, such than a digital watch or clock that displays directly the time for different time zones, the time differences being programmed into these digital devices so that by the simple choice of a country or a specific zone, the corresponding time is displayed automatically.

Document US-3,633,354 relates to a watch allowing to indicate the time simultaneously from two different places due to the presence of two small hands to indicate the hours, the angular position is adjusted independently by two systems of ordered.

Despite the existence of these prior art devices, there are a need for analog devices, for example with display by hands, allowing by the simple choice of a country or a time zone directly display the corresponding time without having to artificially recreate this shift by setting the time again watch.

The invention therefore aims to provide a device for indicating the time of the type which was indicated previously, which can be set to several time zones by a simple and safe maneuver, not risking not affect the time setting setting of the device and allowing display, by means of a marker, the time zone corresponding to the time indicated by the device.

According to the present invention, these objectives are achieved by the fact that the time indication device is characterized in that said dial has a window and in that said device further comprises a crown movable in rotation around a geometric axis, placed behind the dial and carrying at least two marks separated by an angle α and positioned radially so that each of said marks can appear through the window in an angular position of said crown corresponding to a time zone indicated by said associated reference mark, and control means unique able to rotate, on the one hand, return means of setting the time connected to said gear train, in a first position control means and, on the other hand, the crown, in a second position of the control means, in that said gear train comprises a first mobile forming a satellite whose axis is integral with the crown and in that said gear train is shaped so that the rotation of the crown of said angle α generates, by means of said train gears, a rotation of said display means corresponding to the time difference between the two time zones indicated by said markers.

According to an advantageous characteristic of the present invention, the gear train is shaped to allow rotation of the crown in both directions, the time difference can then be positive or negative.

In this way, the change of angular position, in a one way or the other, the crown changes, on the one hand, by train gears, the position of the analog time display means, that is to say the time indicated by said device, and, on the other hand, by the appearance of another marker across the window, the time zone displayed on the dial, associated with this marker and corresponding to the new time indicated.

• un étage inférieur comportant une roue d'entrée reliée auxdits moyens moteurs par un dispositif à friction et engrenant avec une chaussée solidaire de l'extrémité inférieure d'un axe matériel coaxial audit axe géométrique, l'extrémité supérieure dudit axe matériel faisant saillie au dessus du cadran et étant solidaire d'une première aiguille, ladite chaussée engrenant avec une roue inférieure d'un deuxième mobile formant satellite comportant une roue inférieure et une roue supérieure, ladite roue inférieure engrenant également avec lesdits moyens de renvoi de mise à l'heure,
• un étage intermédiaire comportant la roue supérieure du deuxième mobile, solidaire de ladite roue inférieure du deuxième mobile et engrenant avec une roue de liaison montée folle autour de l'axe matériel, ladite roue de liaison engrenant avec la roue inférieure du premier mobile, et
• un étage supérieur comportant la roue supérieure du premier mobile, solidaire en rotation avec ladite roue inférieure du premier mobile et engrenant avec une roue à canon solidaire de l'extrémité inférieure d'un palier monté fou autour de l'axe matériel, l'extrémité supérieure dudit palier faisant saillie au dessus du cadran et étant solidaire d'une deuxième aiguille.

According to a preferred embodiment of the present invention, the first mobile comprises a lower wheel and an upper wheel secured to the same axis and the gear train further comprises:

• a lower stage comprising an input wheel connected to said motor means by a friction device and meshing with a carriageway integral with the lower end of a material axis coaxial with said geometric axis, the upper end of said material axis projecting above of the dial and being integral with a first hand, said carriageway meshing with a lower wheel of a second mobile forming a satellite comprising a lower wheel and an upper wheel, said lower wheel also meshing with said time-setting return means ,
• an intermediate stage comprising the upper wheel of the second mobile, integral with said lower wheel of the second mobile and meshing with a link wheel idly mounted around the material axis, said link wheel meshing with the bottom wheel of the first mobile, and
• an upper stage comprising the upper wheel of the first mobile, integral in rotation with said lower wheel of the first mobile and meshing with a barrel wheel integral with the lower end of a bearing mounted idly around the material axis, the end upper of said bearing projecting above the dial and being integral with a second needle.

Thanks to this compact arrangement of the gear train, effectively direct rotation of the first needle movement by the driving means and, through the reports of the train of gears, the rotation of a second needle. Furthermore, thanks in particular to the first mobile connecting the crown to the gear train and to the friction device, placed between the gear train and the means motors, the rotation of the crown causes the second needle to rotate which shifts by an angle corresponding to the time difference sought.

According to an advantageous characteristic of the present invention, the control means comprise a control rod capable of to be moved in longitudinal translation between said first position allowing to rotate said return setting means to the time and said second position allowing to rotate said crowned.

In this way it is possible, by the operation of a single item, to order either the device time reset, which then generates a rotation of the two needles, or, by the rotation of the crown, a time difference only changing the angular position of the second needle.

In this case, it is provided that said means for returning the hour present a vertical wheel movable in rotation around an axis horizontal, meshing with the bottom wheel of the second mobile and being able to mesh with a vertical gear wheel located at the distal end of said control rod, in said first position of the control rod ordered.

Advantageously, the lower surface of the periphery of said crown is provided with teeth turned opposite said bottom and capable of cooperate with the teeth of a toothed wheel belonging to said means of ordered.

• la première aiguille est une grande aiguille pour l'indication des minutes ;
• la deuxième aiguille est une petite aiguille pour l'indication de l'heure ;
• le rapport de vitesse entre les premier et deuxième mobiles est égal à 1 et le rapport de vitesse entre les étages supérieur et inférieur est égal à 1/12 ;
• si l'on considère R1 comme étant le rapport de vitesse entre le deuxième mobile et les moyens moteurs et R2 comme étant le rapport de vitesse entre la roue de liaison de l'étage intermédiaire et le deuxième mobile, la relation suivante est vérifiée : α/360 (1 - 1/12 x 1/(R2 x R1)) + 1/12 = 0 ;
• si l'on considère R3 comme étant le rapport de vitesse entre le premier mobile et la roue de liaison de l'étage intermédiaire et R4 comme étant le rapport de vitesse entre la roue à canon et le premier mobile, la relation suivante est vérifiée : α/360 (R4 x R3 - 1) - 1/12 = 0 ;
• selon un mode de réalisation préférentielle, R1 = 1/4, R2 = 1/5, R3 = 5, R4= 1/3 et α = 45°.

The following advantageous arrangements are also preferably adopted:

• the first hand is a large hand for indicating the minutes;
• the second hand is a small hand for indicating the time;
• the speed ratio between the first and second mobiles is equal to 1 and the speed ratio between the upper and lower stages is equal to 1/12;
• if R1 is considered to be the speed ratio between the second mobile and the drive means and R2 to be the speed ratio between the connecting wheel of the intermediate stage and the second mobile, the following relationship is verified: α / 360 (1 - 1/12 x 1 / (R2 x R1)) + 1/12 = 0;
• if R3 is considered to be the speed ratio between the first mobile and the connecting wheel of the intermediate stage and R4 to be the speed ratio between the gun wheel and the first mobile, the following relationship is verified: α / 360 (R4 x R3 - 1) - 1/12 = 0;
• according to a preferred embodiment, R1 = 1/4, R2 = 1/5, R3 = 5, R4 = 1/3 and α = 45 °.

• une série de dépressions positionnées sur la surface interne de ladite couronne de façon régulièrement espacée sur un cercle concentrique à ladite couronne, les dites dépressions étant séparées entre elles d'un angle sensiblement égal audit angle α, et
• un tube vertical, disposé entre ledit fond et ladite couronne, dans lequel est logé un ressort de compression à l'extrémité supérieure duquel repose une bille venant prendre appui sur ladite surface interne de la couronne en regard dudit cercle, de sorte que lorsque ladite bille se trouve alignée verticalement avec l'une des dépressions, un repère apparaít au travers de ladite fenêtre.

According to another advantageous configuration, the device further comprises a system for stabilizing the angular position of said crown comprising:

• a series of depressions positioned on the internal surface of said crown in a regularly spaced fashion on a circle concentric with said crown, said depressions being separated from each other by an angle substantially equal to said angle α, and
• a vertical tube, disposed between said bottom and said crown, in which is housed a compression spring at the upper end of which a ball rests coming to bear on said internal surface of the crown opposite said circle, so that when said ball is aligned vertically with one of the depressions, a mark appears through said window.

In this way, a stable angular position is ensured and crown constant outside of periods when a offset of the time indicated by the device, by the rotation of the crown which corresponds to a time zone change.

The invention will be better understood, and features side effects and their advantages will become apparent during the description of a embodiment given below by way of example.

It is understood that the description and the drawings are not given for information only and not limitative.

• la figure 1 est une élévation partiellement transparente d'un dispositif selon la présente invention ;
• la figure 2 est une vue en coupe selon la direction II-II de la figure 1 ;
• la figure 3 est une vue simplifiée de la figure 1 sur laquelle le dispositif est dans une première position ;
• la figure 4 est un schéma illustrant la cinématique du dispositif de la figure 3 selon une vue identique à celle de la figure 2 ;
• les figures 5 et 6 correspondent respectivement à des vues identiques à celles des figures 3 et 4 pour une deuxième position du dispositif selon l'invention ; et,
• les figures 7 et 8 correspondent à des vues identiques à celles des figures 3 et 4 pour une troisième position du dispositif.

Reference will be made to the accompanying drawings, in which:

• Figure 1 is a partially transparent elevation of a device according to the present invention;
• Figure 2 is a sectional view along the direction II-II of Figure 1;
• Figure 3 is a simplified view of Figure 1 in which the device is in a first position;
• Figure 4 is a diagram illustrating the kinematics of the device of Figure 3 in a view identical to that of Figure 2;
• Figures 5 and 6 correspond respectively to views identical to those of Figures 3 and 4 for a second position of the device according to the invention; and,
• Figures 7 and 8 correspond to views identical to those of Figures 3 and 4 for a third position of the device.

The device for indicating the time shown on the Figures 1 to 8 can be produced, depending on the dimensions used, in the form a watch or a pendulum without modifying the description which go follow. This device for indicating the time 10 comprises a case 12 containing the mechanism, this housing 12 comprising a bottom 14, a wall cylindrical lateral 16 and being delimited in the upper part by a dial 18 at the upper surface of which we find all the inscriptions necessary for the time reading such as whole numbers in Roman numerals or in Arabic numerals (reference 20) as well as fancy names or decoration patterns.

Conventionally in itself, the device 10 is provided with means analog time display in the form of a large hand 22 for the indication of the minutes and a small hand 24 for the indication for hours, these two hands 22, 24 being mobile in rotation around the same geometric axis (X0, X0 '). The large needle 22 is integral with the upper end of a material axis 26 whose lower end is integral with a center gable or roadway 28. This roadway 28 meshes with an input wheel 30 whose axis is connected, via a friction system 32, to motor means 34. These motor means 34 may be of a nature diverse. Conventionally the motor means 34 consist of a motor step by step controlled by an integrated circuit, itself powered electrically by means of a battery and subjected to the pulses of a oscillator or quartz.

The small hand 24, which makes a full turn of the dial in twelve hours, is driven indirectly, by the same motor means 34 with a speed ratio of 1/12 compared to the large needle 22. This is produced by a gear train 36 composed of three stages 36a, 36b and 36c and connecting the roadway 28 to a cannon wheel 38. The cannon wheel is integral with the lower end of a bearing 39 mounted idly around the axis central 26 and the upper end of which protrudes above the dial 18, is integral with the small needle 24 which is placed under the large needle 22. The operation of the device 10, apart from the phases of time setting or time difference is as follows: at the floor level bottom 36a of the gear train 36, the motor means 34 drive in rotation the input wheel 30 meshing with the roadway 28, or pinion of center, at a speed ratio equal to 1, the roadway 28 and the wheel inlet 30 having the same diameter. Besides the entry wheel 30, the roadway 28 meshes with another toothed wheel 41 of larger diameter forming the lower wheel of a second mobile 40 rotating around an axis (X1, X1 ') fixed relative to the central axis (X0, X0'). Material axis 44, bearing jointly the lower 41 and upper 42 wheels of the second mobile 40, is rotatably mounted at the bottom 14 of the housing.

The second mobile 40 also includes an upper wheel 42 surmounting the lower wheel 41 and belonging to an intermediate stage 36b of the gear train 36. This upper wheel 42 meshes with a connecting wheel 46 mounted madly around the central axis 26 and meshing with a pinion 51 forming the lower wheel of a first mobile 50 whose axis support material 54 is integral with a crown 60.

At the upper stage 36c of the gear train 36, the upper wheel 52 of the first mobile 50 meshes with the barrel wheel 38 of so that the rotational movement of the motor means 34 is transmitted up to the small needle 24 with a ratio of 1/12 between the barrel wheel and pavement 28, that is to say between the upper floor 36c and the lower floor 36a of gear train 36.

The first mobile 50 is mounted in rotation about an axis geometric (X2, X2 ') which is, like the axis (X1, X1') of the second mobile 40, parallel to the axis (X0, X0 '). However, unlike the axis (X1, Xl '), the axis (X2, X2 ') is not fixed relative to the axis (X0, X0') but is movable rotating around the axis (X0, X0 ') because it follows the angular displacement of crown 60.

The time indication device 10 also includes control means 70 allowing the time setting of the device 10 or jet lag. In the preferred embodiment illustrated, these control means 70 are unique and include a rod control 72 horizontal, the proximal end of which protrudes from the housing by an opening disposed at the side wall 16, a head grip 74 being fixed to this proximal end. The distal end of the control rod 72 carries a toothed wheel 76 of axis (Y0, Y0 ') horizontal and perpendicular to the axis (X0, X0 '). The control rod 72 is carried by a U-shaped stirrup 80 whose ends form a landing for the rod 72, two compression springs 82 each extending between the internal face of one of the legs of the stirrup 80 and a stop rib 84 annular placed around the control rod 72. These springs 82 are identical and tend to bring the control rod 72 into a position rest in which the stop rib 84 is centered relative to the two branches of stirrup 80.

If the user pushes the control rod 72, it comes in stop in a first extreme position or advanced position in which the toothed wheel 76 cooperates with time-setting return means consist of a vertical return wheel 86 movable in rotation around a horizontal axis (Y1, Y1 '). The deflection wheel 86 has a double system of teeth for meshing with, on the one hand, the toothed wheel 76 and, on the other share, the lower wheel 41 of the second mobile 40. Thus, in the position projection of the control rod 72, by rotating the gripping head 74 around the axis (Y0, Y0 '), the user can thus, through the train gears 36, simultaneously rotate the large needle 22 and the small hand 24 for resetting the device 10, the resistant torque developed by the pavement 28 being sufficient to disengage the wheel input 30 of the motor means 34 by eliminating the effect of the system at friction 32.

In a second extreme stop position, corresponding to a retracted position, the control rod 72 kept pulled by the traction exerted by the user on the gripping head 74, allows the toothed wheel 76 to mesh with a toothing 61 arranged at the lower surface of the periphery of the crown 60, facing the bottom 14 of the housing 12. It is in this withdrawal position that the control rod 72 allows for an angular offset of the crown 60 resulting in a jet lag, that is to say the rotation of the only small hand 24, as described below.

Contrary to what happens in the case of setting the time, when the crown 60 is rotated, the friction system 32 remains active for so that the drive means 34 remain coupled to the input wheel 30, which immobilizes the central axis 26 and the large needle 22.

If the user rotates the crown 60 by an angle α, the axis (X2, X2 ') and the first mobile 50 also rotate by an angle α relative to the central axis (X0, X0'), the small needle 24 then moving by an offset angle D verifying the following formula: D = α (1- R4 x R3) where R4 is the ratio of the upper stage, that is to say the ratio between the barrel wheel 38 and the first mobile 50 and R3 is the ratio between the first mobile 50 and the connecting wheel 46.

At the end of this time shift operation, the stem of control 72 returns to its illustrated rest position, the train of gears 36 then operating normally between the driving means 34 and the small needle 24, the first mobile 50 remaining in its new angular position.

In the illustrated embodiment, it is intended that get a one hour time difference from the small hand 24 when α = 45 °, α being the angle of rotation of the crown 60.

The position of the crown 60 is identified by the display of marks 62 carried on the upper surface of the crown 60, one of these marks 62 which can be viewed through a window 19 cut out from the dial 18 at the same distance from the axis (X0, X0 ') as the pins 62. The marks 62 (A, B, C ...) are spaced from each other by the same angle α.

In the initial position shown in Figures 1 and 3, the mark B visible through window 19 corresponds to a time difference no. We will take as the starting position of hands 22 and 24, that illustrated in FIG. 3, position in which the device 10 indicates eight quarter past eight (8.15 a.m.).

To move to the position illustrated in Figure 5, from the starting position of FIG. 3, the user has maneuvered the means of control 70 so as to rotate the crown 60 by an angle equal to - α (- 45 °), which caused, through the gear train, a rotation of the small needle 24 at an angle equal to D, that is to say 1/12 turns or 30 °, of so that in Figure 5 the device 10 displays a quarter past nine (9.15 a.m.) and it is the mark C, corresponding to a time difference of + 1 hour, which appears in window 19.

On the other hand, if from the initial position of figure 3, the user rotates the crown 60 by an angle equal to + 45 ° (+ α or 1/8 of turn), it is the reference A which appears in the window 19, this reference corresponding to a time difference of - 1 hour, and the small hand 24 a rotated by an angle equal to - 30 °, that is to say - 1/12 turn, so that the device displays a quarter past seven (7.15 a.m.).

Thus, thanks to this arrangement, it is possible, at any time, to perform a time difference in the display of the device 10, by acting only on the small hand 24, this time difference may be done in both directions. This advantageous arrangement is made possible due to the fact that the crown 60 and all the cogs of the train gear 36 can rotate in both directions which optimizes order handling regardless of the number of hours offset that you want to apply to the device.

In addition, this time difference can correspond to any number of hours desired. Indeed, the number of benchmarks 62 is not limited to 3 as in the figures but may be greater: up to 8 for α = 45 °. In addition, the crown can be rotated more than one turn to obtain the jet lag desired.

It is of course possible to design other devices having the value of the angle at a value different from 45 °, such as 60 °, by recalculating the appropriate ratios at the level of the gear train 36.

The example illustrated in FIGS. 1 to 8 presents three references 62 (A, B and C) each corresponding to three adjacent time zones which can correspond to the three time zones present within the Europe of so that the device illustrated can constitute a watch usable in any the European territory, each of the landmarks 62 (A, B, C) corresponding to one of these time zones and can be replaced by the initials of a country the corresponding time zone.

So that the crown 60 remains in a stable position between two jet lag maneuvers, it is expected that the device 10 includes a stabilization system 90 cooperating reversibly with the crown, in the positions of crown 60 corresponding to the display of one of the markers 62 through the window 19. So preferential, as illustrated in FIGS. 1 to 8, this system of stabilization 90 includes a ball 92 mounted on a spring 94 placed vertically in a tube 96, the opening of which is oriented in the direction of the crown.

A series of depressions 98 is located on the lower surface of crown 60 along a circle concentric with crown 60, the depressions being regularly spaced at an angle equal to the angle α.

The compression spring 94 keeps the ball in abutment against the crown 60 so that when the ball faces a depression 98, the ball 92 is partially housed in this depression 98. The crown remains then stable in this angular position as long as the user does not exercise sufficient torque on the control rod 72 to overcome the compressive strength of spring 94.

Advantageously, it is expected that when the ball arrives in look of one of the depressions 98, one of the marks 62, appears through window 19.

The device 10 which has just been presented can also be used for jet lag which, instead of coming from a time zone change, comes from the time difference between the time summer and winter time.

It is understood that other gear trains having a arrangement different from that of the gear train 36 described and illustrated above may allow the same type of jet lag to be obtained.

Without departing from the scope of the present invention, the control means 70 may have a shape other than that of the control rod 72 and can also be in the form of two separate control systems, one for setting the time and the other for the time difference created by the angular movement of the crown 60.

The device described above can also be adapted for the incorporation of an additional needle for the indication of seconds via an additional gear stage, preferably placed above the upper stage of the gear train 36.

Claims (11)

Time indication device (10), such as a watch, comprising: a- a housing (12) provided with a bottom (14) and a dial (18), b- analog time display means (22, 24), c- motor means (34), and d- a gear train (36) for transmitting the movement of the motor means (34) to said display means (22, 24), characterized in that said dial (18) has a window (19) and in that said device (10) further comprises: e- a crown (60) movable in rotation about a geometric axis (X0, X0 '), placed behind the dial (18) and carrying at least two marks (62) spaced apart by an angle α and positioned radially so that each of said marks (62) can appear through the window (19) in an angular position of said crown (60) corresponding to a time zone indicated by said associated mark (62), and f- single control means (70) capable of driving in rotation, on the one hand, return means (86) for setting the time connected to said gear train (36), in a first position of the means control (70) and, on the other hand, the crown (60), in a second position of the control means, in that said gear train (36) comprises a first mobile (50) forming a satellite whose axis is integral with the crown (60) and in that said gear train (36) is shaped so that the rotation of the crown (60) of said angle α generates, by means of said gear train (36), a rotation of said display means (22, 24) corresponding to the time difference between the two time zones indicated by said marks ( 62). Device according to claim 1, characterized in that said control means (70) include a control rod (72) capable of being moved in longitudinal translation between said first position for driving in rotation said return means (86) of setting the time and said second position for driving in rotation said crown (60). Device according to any one of the preceding claims, characterized in that said first mobile (50) comprises a lower wheel (51) and an upper wheel (52) secured to the same axis (54) and in that said gear train (36) also includes: a lower stage (36a) comprising an input wheel (30) connected to said motor means (34) by a friction device (32) and meshing with a solid roadway (28) of the lower end of a material axis ( 26) coaxial with said geometric axis (X0, X0 '), the upper end of said material axis (26) projecting above the dial (18) and being integral with a first needle (22), said carriageway (28) meshing with a lower wheel (41) of a second mobile (40) forming a satellite comprising a lower wheel (41) and an upper wheel (42), said lower wheel (42) also meshing with said return means (86) for setting on time, an intermediate stage (36b) comprising the upper wheel (42) of the second mobile (40), integral with said lower wheel (41) of the second mobile (40) and meshing with a connecting wheel (46) mounted loosely around the material axis (26), said connecting wheel (46) meshing with the lower wheel (51) of the first mobile, and an upper stage (36c) comprising the upper wheel (52) of the first mobile (50), integral in rotation with said lower wheel (51) of the first mobile (50) and meshing with a barrel wheel (38) integral with the lower end of a bearing (39) mounted idly around the material axis (26), the upper end of said bearing (39) projecting above the dial (18) and being integral with a second needle (24) . Device according to claims 2 and 3, characterized in that said time setting return means have a vertical wheel (86) mobile in rotation around a horizontal axis (Y0, Y0 '), meshing with the lower wheel (41) of the second mobile (40) and being able to mesh with a vertical gear (76) located at the distal end of said control rod (72), in said first position of the control rod control (72). Device according to any one of the preceding claims, characterized in that said gear train (36) is shaped so as to allow rotation of the crown (60) in both directions, the offset time worked being positive or negative. Device according to any one of the preceding claims, characterized in that the lower surface of the periphery of said crown (60) is provided with teeth (61) turned opposite said bottom (14) and able to cooperate with the teeth of a toothed wheel (76) belonging to said control means (70). Device according to any one of Claims 2 to 6, characterized in that said first needle is a large needle (22) for the indication of the minutes, in that said second hand is a small hand (24) for indicating the time, in that the speed between the first and second mobiles (40, 50) is equal to 1 and in this that the speed ratio between the upper (36c) and lower (36a) stages is equal to 1/12. Device according to claim 7, characterized in that, if R1 is considered to be the speed ratio between the second mobile (40) and the drive means (34) and R2 as the speed ratio between the connecting wheel (46) of the intermediate stage (36b) and the second mobile (40), the following relationship is verified: α / 360 (1-1 / 12 × 1 / (R2 × R1)) + 1/12 = 0. Device according to claim 7, characterized in that, if R3 is considered to be the speed ratio between the first mobile (50) and the connecting wheel (46) of the intermediate stage (36b) and R4 as being the speed ratio between the cannon wheel (48) and the first mobile (50), the following relationship is verified: α / 360 (R4 × R3-1) -1 / 12 = 0. Device according to claims 8 and 9, characterized in that R1 = 1/4, R2 = 1/5, R3 = 5, R4 = 1/3 and α = 45 °. Device according to any one of the preceding claims, characterized in that it further comprises a system for stabilizing (90) the angular position of said crown (60) comprising: a series of depressions (98) positioned on the internal surface of said crown (60) in a regularly spaced fashion on a circle concentric with said crown (60), said depressions (98) being separated from each other by an angle substantially equal to said angle α, and a vertical tube (96), disposed between said bottom (14) and said crown (60), in which is housed a compression spring (94) at the upper end of which rests a ball (92) coming to bear on said surface internal crown (60) opposite said circle, so that when said ball (92) is aligned vertically with one of the depressions (98), a mark (62) appears through said window (19).

Images