HK1231971B - Moon phase display mechanism for timepieces - Google Patents

Description

Moon phase display mechanism for watches

Technical Field

The invention relates to a moon phase display mechanism comprising a control wheel driven by a movement, which controls a moon phase disc behind an aperture in a dial.

The invention also relates to a watch or timepiece comprising a movement.

The present invention relates to the field of horological complications, in particular astronomical complications.

Background Art

Moon phase displays are expensive complications in horology.

However, the known mechanism cannot properly account for the correct display that is valid in both the Northern and Southern Hemispheres. In fact, the new moon visible in one hemisphere does not correspond to the new moon in the other hemisphere, but rather to its mirror image. This makes it difficult to correctly interpret the double moon.

International patent WO 2011/113170 in the name of BVLGARI ROTH & GENTA discloses a retrograde moon phase display mechanism with a double heart-shaped cam, each heart-shaped piece corresponding to a lunar cycle, so that the phase indicator wheel moves in opposite directions during the waxing and waning of the moon phase.

European Patent EP 2392976 in the name of Audemars Piguet discloses a highly complex mechanism for a more detailed moon phase display than known mechanisms, requiring stacked discs on three levels and very specific components, which, in the case of enamel dials and discs, require new tools and the management of additional components. This mechanism can be adapted to either hemisphere through the use of a special disc that is installed during assembly of the watch, but it does not allow for instantaneous switching of the moon phase display to match the view in one hemisphere or the other.

US Patent No. 2014/247699 in the name of TIMEX discloses a known mechanism for an electronic watch designed to simultaneously or selectively display the moon phases for the northern and/or southern hemispheres.

Summary of the Invention

The present invention proposes a direct reading, requiring no understanding for observers in the Northern Hemisphere or Southern Hemisphere, using a simple mechanism that is particularly compact in thickness and can be maintained and changed at will. The invention is economical because it uses a conventional dial and disk and does not require additional display components. The moon disc control mechanism of the invention is designed to be easily integrated into a mechanism with a conventional moon wheel. The invention preferably uses a conventional control device, such as a GMT or similar control device, which can be easily reused in this specific application to drive a shuttle that, without any other function, causes the moon disc to rotate, allowing it to be viewed in the selected hemisphere.

To this end, the invention relates to a moon phase display mechanism having a control wheel driven by a movement, which controls a moon phase disc behind an aperture in the dial, as described in claim 1 .

The invention also relates to a watch or timepiece comprising such a movement, as claimed in claim 6.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become apparent upon reading the following detailed description with reference to the accompanying drawings, in which:

- Figure 1 shows a schematic perspective top view of the mechanism according to the invention as seen by a user.

- Figure 2 shows the same mechanism in a similar manner, viewed from below.

- Figure 3 is a top plan view corresponding to Figure 1.

- Figure 4 is a bottom plan view corresponding to Figure 2.

– Fig. 5 is a cross-sectional view taken along line A-A of Fig. 3 .

– Figure 6 is an exploded perspective top view corresponding to Figure 1 .

- Figure 7 is an exploded perspective bottom view corresponding to Figure 2.

- Figure 8 is a bottom view showing hidden parts of the mechanism not visible in the other figures, and illustrating the collaboration of one arm of the double lever with the heart-shaped cam.

- Figure 9 shows the Moon as seen by an observer in the Northern Hemisphere at a given moment, and Figure 10 shows the Moon as seen in the Southern Hemisphere at the same moment.

- Figure 11 shows a schematic front view of a watch comprising a mechanism according to the invention and comprising a separate display device indicating the hemisphere in which the moon is displayed.

- Figure 12 is a block diagram showing such a watch comprising a movement and a control device both cooperating with a mechanism according to the invention.

DETAILED DESCRIPTION

The present invention relates to a moon phase display mechanism 1 for a watch or a clock.

In a known manner, the complete display mechanism comprises a conventional drive wheel, known as the moon wheel (usually having 59 teeth), which operates stepwise or continuously (not shown in the accompanying drawings) and is arranged to drive two moon phase indicator wheels 100 and 110 which rotate in directions opposite to each other thanks to the addition of an intermediate wheel (not shown) for driving one of these two moon phase indicator wheels 100 and 110.

Each of the two moon phase indicator wheels 100 and 110 carries a cam for resetting to 0, respectively 90, 80. Advantageously, as shown in the figures, these cams 80, 90 are heart-shaped cams similar to those used in chronographs or time zone change mechanisms.

According to the invention, moon phase display mechanism 1 thus comprises the following components, coaxial along a common pivot axis D and superposed on one another:

– a first moon phase indicator wheel 110 , which carries a first heart-shaped cam 80 by means of a tube 111 ;

A second moon phase indicator wheel 100 , comprising an aperture 101 through which the tube 111 passes and which directly carries the second heart-shaped cam 90 .

The moon phase display mechanism 1 also includes the following components centered on the same axis D:

– a control wheel 30 driven by movement 900 and carrying a set of levers arranged to cooperate with cams 80 and 90 ;

- a moon phase disc 20 pivoted by a control wheel 30;

A moon phase display dial 10 comprising an aperture 11 behind which a moon phase disc 20 moves.

The control wheel 30 is connected alternately to two feelers or rollers by means of a double rod 40 in order to obtain alternately information from one or the other of the two cams 80 or 90 (ie North or South).

According to the invention, the control wheel 30 comprises means 31 for guiding the double lever 40 comprising two arms 43, 53 arranged so that at any one time only one of them cooperates in contact with one of the second heart-shaped cam 90 and the first heart-shaped cam 80. Each heart-shaped cam 80, 90 is arranged to display the phase of the moon as seen in the northern or southern hemisphere and to allow the moon phase disc 20 to pivot in the direction appropriate for that hemisphere.

The change of hemispheres is controlled by the action of control device 500 causing pivoting of control wheel 30, which is free-wheeled but elastically held and secured to moon phase disc 20 by a first spring 70. This first spring 70 comprises a finger 71 arranged to intercept beak 33 of control wheel 30.

More specifically, the change of hemisphere is achieved by means of a control wheel 30 operating as a free wheel but elastically held by a first spring 70 positioned and secured below moon phase disc 20 by means of pins 74, 75 or the like. This first spring 70 is movable within a limited range inside a cutout 32 of control wheel 30 and comprises a finger 71 arranged to intercept beak 33 of control wheel 30.

More specifically, control wheel 30 comprises an elongated, preferably annular, hole forming said means 31 for guiding this double lever 40 about axis D, in which hole moves a trunnion 48 included in double lever 40. A hole 44 in trunnion 48 guides a pin 41 or the like fastened to moon phase disc 20 in hole 21.

The relative pivoting movement between control wheel 30 and moon phase disc 20 is thus limited by the travel of trunnion 48 in oblong hole 31 .

The double rod 40 comprises the following components in two different parallel planes:

- a lower arm 43 carrying a hammer 42 arranged to cooperate with a second heart-shaped cam 90;

An upper arm 53 carrying a hammer 54 arranged to cooperate with a first heart-shaped cam 80 .

This double lever 40 also comprises a return arm 51 articulated by an arbour 63 at the end of a second spring 60 , the second spring 60 being fastened here to the control wheel 30 by means of pins 63 , 64 or the like.

At any given moment, moon phase display mechanism 1 provides a moon phase display in only one hemisphere, which obviates any need for interpretation by the user.

The user can activate the other hemisphere by means of a conventional control device 500, such as a pusher/button, a pull-out or the like, and each time mechanism 1 remains stationary in its new position - the northern or southern hemisphere. Preferably, the control device 500 is actuated against an elastic reset device, such as a spring, and the reciprocator operated by the control device is immobilized in the manner of a ballpoint pen by a reversible locking device. Advantageously, therefore, in a known manner, the hemisphere selection control circuit can also indicate, by means of a separate display device, the hemisphere in which the currently displayed moon phase is located after operation of the control device 500. FIG11 shows a non-limiting example in which a pointer 502 in the aperture 501 indicates whether the moon phase is present in the northern or southern hemisphere.

Action on the control device 500 causes the control wheel 30 to pivot. It will be understood that this action on the control device 500 is reversible: two successive actions on the control device 500 have the effect of pivoting the control wheel 30 in two opposite directions.

In the rest position of mechanism 1, that is, when it is not actuated, a given hemisphere is selected, and the combination of the above-described devices ensures that one of the hammers 42, 54 of double lever 40 remains supported on a flat portion 82, 92 included in the associated heart-shaped piece 80, 90. Furthermore, since first moon phase indicator wheel 110 or second moon phase indicator wheel 100 is driven by a moon wheel driven by watch movement 900, a torque can be applied to double lever 40, causing trunnion 48 to remain supported at one end of oblong hole 31 of control wheel 30. Finger 71 of first spring 70 is now abutted against a first side of beak 33 of control wheel 30. Moon phase disc 20 is thus driven without play in a first pivoting direction.

When control device 500 is actuated by the user, this action has the effect of imparting a pivoting movement on control wheel 30 in the direction opposite to that previously described, and trunnion 48 is transferred to the other end of elongated hole 31, which has the effect of pivoting double lever 40 against second spring 60 (which had previously held it in position on one of the heart-shaped pieces 80, 90), so that the other hammer 54, 42 then bears on the other heart-shaped piece 90, 80, in contact with its flat portion 92, 82, and then drives control wheel 30 in the opposite direction, causing first spring 70 to jump, finger 71 of which passes over beak 33 and then remains bearing on the second side of beak 33. Once the position is determined, control wheel 30 then regularly pivots moon-phase disc 20 in the opposite direction.

Subsequent actions on the control device 500 reversibly initiate the operation.

Display mechanism 1 according to the invention is particularly stable and does not require any particular friction surfaces: the torque supplied to the moon wheel by movement 900 is sufficiently high to ensure that one of arms 43 , 53 of double lever 40 is permanently driven by corresponding heart 80 , 90 , and that the thrust transmitted to control wheel 30 by the control device makes it possible to rotate through the notch corresponding to finger 71 passing over beak 33 .

In short, this simple, compact mechanism offers new and advantageous functions to the user. It is driven in the conventional manner by the moon wheel and can easily replace any conventional moon phase display mechanism, the only significant modification being to equip a watch 1000 combining movement 900 and mechanism 1 with a control device 500, such as those used in GMT time zone change mechanisms.

The present invention also relates to a watch 1000 or timepiece comprising a movement 900 arranged to permanently drive the first moon phase indicator wheel 110 and the second moon phase indicator wheel 100 in opposite directions. Furthermore, the watch 1000 comprises a control device 500 arranged to pivot the control wheel 30 to control the change of the moon phase display in the northern hemisphere or the southern hemisphere.

More particularly, the control device 500 is arranged so that after each operation of the control device 500, the mechanism 1 remains immobilized in the new position reached, the control device 500 being actuated against elastic return means and the reciprocator controlled by such control device 500 being immobilized by reversible locking means.

More particularly, watch 1000 includes separate display means for indicating whether the northern or southern hemisphere is where the moon phase currently displayed is located after actuation of control means 500.

Claims (8)

1. A moon phase display mechanism (1), the moon phase display mechanism (1) comprising a control wheel (30) driven by a movement (900), the control wheel (30) driving a moon phase disk (20) behind an aperture (11) of a dial (10), characterized in that the moon phase display mechanism (1) comprises: a first moon phase indicator wheel (110) carrying a first heart-shaped cam (80), and a second moon phase indicator wheel (100) carrying a second heart-shaped cam (90), the first moon phase indicator wheel (110) and the second moon phase indicator wheel (100) being coaxial. The control wheel (30) is stacked and permanently driven in opposite directions, and includes a guide device (31) for guiding a double rod (40) comprising two arms (43, 53), the two arms (43, 53) being arranged such that at any given time only one arm cooperates in contact with one of the second heart-shaped cam (90) and the first heart-shaped cam (80), each heart-shaped cam (80, 90) being arranged to display the lunar phase visible in the Northern or Southern Hemisphere, and allowing the lunar phase disk (20) to pivot in a direction suitable for the hemisphere. 2. The moon phase display mechanism (1) as claimed in claim 1, characterized in that the change of the hemisphere is controlled by the pivoting action of the control wheel (30) by the control device (500), the control wheel (30) being a free wheel but elastically held and fastened to the moon phase disk (20) by a first spring (70), the first spring (70) including a finger-shaped portion (71) arranged to intercept the beak (33) of the control wheel (30). 3. The moon phase display mechanism (1) as claimed in claim 1, characterized in that the guiding device (31) includes an elongated hole in which a trunnion (48) contained in the double rod (40) is movable, the trunnion (48) guiding a pin (41) fastened to the moon phase disk (20) for driving the moon phase disk (20). 4. The moon phase display mechanism (1) as claimed in claim 1, characterized in that the double rod (40) includes a lower arm (43) and an upper arm (53) on two different parallel planes, the lower arm (43) carrying a hammer (42) arranged to cooperate with the second heart-shaped cam (90), the upper arm (53) carrying a hammer (54) arranged to cooperate with the first heart-shaped cam (80), and the double rod (40) further includes a reset arm (51) hinged at the end of a second spring (60) fastened to the control wheel (30). 5. The moon phase display mechanism (1) as claimed in claim 1, characterized in that the first moon phase indicator wheel (110) carries the first heart-shaped cam (80) by means of a tube (111) passing through the second moon phase indicator wheel (100), and the second moon phase indicator wheel (100) directly carries the second heart-shaped cam (90) arranged in a plane different from the first heart-shaped cam (80). 6. A watch (1000) or clock including a movement (900), the watch (1000) or clock further comprising a moon phase display mechanism (1) according to any one of claims 1-5, characterized in that the movement (900) is arranged to drive the first moon phase indicator wheel (110) and the second moon phase indicator wheel (100) in opposite directions at all times, the watch (1000) including a control device (500) arranged to pivot the control wheel (30) to control the change of the moon phase display in the Northern or Southern Hemisphere. 7. The watch (1000) according to claim 6, characterized in that the control device (500) is arranged such that after each operation of the control device (500), the moon phase display mechanism (1) remains fixed in the new position reached; the control device (500) is actuated against the elastic reset device, and the reciprocator controlled by the control device (500) is fixed by a reversible locking device. 8. The watch (1000) according to claim 7, characterized in that the watch (1000) includes a separate display device for indicating whether the currently displayed moon phase is in the Northern or Southern Hemisphere after the control device (500) is actuated.