EP1475679A1 - Device for displaying the phases of the moon, in particular in a timepiece - Google Patents

Abstract

The device has an axle that is rotatably mounted on a turntable to make a predefined number of turns by lunar month. A transmission mechanism provides a kinematical link between the axle and a mobile indicator (3) to enable the indicator to make a turn by lunar month with respect to a dial (1). The indicator is rotatably mounted at a point of the mechanisms rotating support that makes two turns by lunar month. The mobile indicator moving behind the dial includes an S-shaped separation line between a dark and a bright zone seen across a circular aperture of the dial. The indicator includes a rotational axis that passes by a center of symmetry of the separation line. The transmission mechanism includes another rotational axis de-centered with respect to the aperture. The rotating support of the transmission mechanism includes a trajectory passing by a center of the circular aperture of the dial.

Description

The present invention relates to a device for displaying the phases of the moon, especially in a watch or other timepiece, comprising a dial equipped with a circular window, a moving indicator in the form of a plate, moving behind the dial and having a substantially S-shaped dividing line between a dark area and a bright area which can be seen through the window, the indicator having a pivot axis which passes through a center of symmetry of the separation line, an input element rotatably mounted on a plate and making a determined number of turns per lunation, and a transmission mechanism ensuring a kinematic connection between the input element and the indicator.

In traditional moon phase displays, a disc bearing two images of the full moon makes a U-turn per lunation behind a semi-circular window of particular shape, illustrated for example in the patent US 508 467. One of the edges of the window has two convex arcs which bite on the image of the full moon, respectively as the moon increases and decreases. The shape of the moon image thus displayed is correct only at the beginning and at the end of the lunation (starting from the new moon), when the lit part has the shape of a crescent, and at full moon. During the other phases, the displayed image has a shape false, because the shape of the dividing line between the light area and the area dark does not conform to reality: it is curved instead of being straight at first and at the last quarter, and it is curved the wrong way between each quarter and the full moon.

Different solutions have been proposed to avoid this drawback.

A display device of the kind indicated above in the preamble is described in US Patent 6,507,536 and has two rotating indicator discs partially superimposed, each carrying a dark area delimited by a curve. The rest of the upper disc is transparent to reveal part of the disc lower, outside the new moon phase. The two discs are driven by synchronously by gears. Their respective dark areas are combine behind the window to give, at each phase of the moon, an image where the shape of the light area corresponds as much as possible to that of the moon seen from the Earth. Such a device is relatively bulky in plan. At the phases where the line of separation is formed by combining the dark areas of the two discs, cannot always avoid the appearance of a break in this line where the edges of the two dark areas intersect. Also, the image of the moon cannot be formed in a single plane, since it consists of two offset parts mutually deep in the direction of vision, and this constitutes a drawback from an aesthetic point of view.

In patent application EP 1 103 872, the moon is represented by a transparent circular disc which moves linearly in front of a dark screen having a curved elongated opening. The width of the opening varies by a maximum in the middle, corresponding to the diameter of the lunar disc, zero at the ends. The lunar disc moves by pressing against a sinuous cam surface, so that one edge of the opening is tangent to the disc and the other edge forms a line of separation roughly in line with reality, between the clear part and the dark part of the lunar disc. However, the device described in this document is too bulky to be incorporated into a watch. In addition, such a display is difficult to read if it is not lit from behind.

The present invention relates to a device for displaying the lunar phases making it possible to largely avoid the drawbacks of the prior art and to show, in a circular window, an image of the illuminated area and the area dark of the moon that is as close as possible to reality. An additional goal is to allow the two areas mentioned above to be represented in the same plane.

To this end, the invention relates to a display device of the kind indicated in preamble, characterized in that the transmission mechanism comprises a support rotary making two turns per lunation and whose axis of rotation is offset relative to at the counter, in that the indicator is pivotally mounted at a point on the rotary support whose path passes through the center of the window, and in that said kinematic link is arranged so that the indicator performs one revolution per lunation in relation to the dial.

Compared to the device illustrated by US Pat. No. 6,507,536, this arrangement is distinguishes above all by the use of a single mobile indicator, whose movement is more complex than the simple rotary movement provided for in said patent. Firstly, this makes it possible to optimally combine the S-shape of the line of separation and movement of the indicating organ with respect to the position and window size, so that the part of the dividing line visible in the window as closely as possible to reality. On the other hand, the light area and the dark area of the indicator member can advantageously be in the same plane.

In addition, this arrangement allows a particularly embodiment advantageous which is characterized in that the movement of the indicator during a the lunation includes a first and a third stage during which the indicator moves without turning noticeably relative to the dial, and a second and a fourth step during each of which the indicator moves by turning substantially half a turn from the dial. Thanks to such a combination of translation and rotation movements, it is possible to change the image displayed as a function of time in a way that best imitates the evolution of the appearance of the moon as a function of time.

la figure 1 est une vue en plan par transparence du mécanisme d'un mode de réalisation préféré d'un dispositif d'affichage des phases de lune selon l'invention, destiné à être entraíné par un mouvement d'horlogerie,

la figure 2 est une vue en coupe suivant la ligne brisée II-II de la figure 1,

les figures 3 à 5 représentent en plan différents niveaux du mécanisme représenté aux figures 1 et 2,

la figure 6 représente en perspective le mécanisme vu de dessous,

les figures 7 à 14 montrent huit positions successives de l'indicateur du dispositif d'affichage, correspondant à des phases de lune décalées chacune d'un huitième de la durée d'une lunaison,

la figure 15 est une vue en plan analogue à la figure 1, représentant un autre mode de réalisation du mécanisme du dispositif d'affichage,

la figure 16 est une vue en coupe schématique suivant la ligne XVI-XVI de la figure 15,

la figure 17 est une vue en plan analogue à la figure 1, représentant encore un autre mode de réalisation du mécanisme du dispositif d'affichage, et

la figure 18 est une vue en coupe schématique suivant la ligne XVIII-XVIII de la figure 17.

Other characteristics and advantages of the present invention will appear in the following description of a preferred embodiment and of various variants, serving as nonlimiting examples, with reference to the appended drawings, in which:

FIG. 1 is a plan view by transparency of the mechanism of a preferred embodiment of a device for displaying the moon phases according to the invention, intended to be driven by a clockwork movement,

FIG. 2 is a sectional view along the broken line II-II of FIG. 1,

FIGS. 3 to 5 show in plan different levels of the mechanism represented in FIGS. 1 and 2,

FIG. 6 represents in perspective the mechanism seen from below,

FIGS. 7 to 14 show eight successive positions of the indicator of the display device, corresponding to moon phases offset each by an eighth of the duration of a lunation,

FIG. 15 is a plan view similar to FIG. 1, showing another embodiment of the mechanism of the display device,

FIG. 16 is a schematic sectional view along the line XVI-XVI of FIG. 15,

FIG. 17 is a plan view similar to FIG. 1, showing yet another embodiment of the mechanism of the display device, and

FIG. 18 is a schematic sectional view along the line XVIII-XVIII of FIG. 17.

With reference to FIGS. 1 to 6, the device for displaying the moon phases comprises a dial 1, which can be the dial of a watch in which the device is installed, this dial having a circular window 2 through which the observer can see a moving indicator 3 in the form of a plate, which moves in its own plane just behind dial 1. The upper surface of indicator 3 is subdivided into a dark zone 4 and a light zone 5 which are separated from each other by a sinuous line 6 approximately S-shaped, as seen more clearly in Figure 7. The dividing line 6 has rotational symmetry by relative to its central point C, which is preferably on a straight section 7 from line 6. Point C coincides with a pivot axis 8 of indicator 3. From preferably, the dark area 4 is black and the light area 5 is yellow commonly used in moon phase displays, but other colors are usable. The terms "dark" and "light" used here to describe zones 4 and 5 of the indicator are only of relative value and should be interpreted as qualifying tones or colors capable of representing the parts of the moon which are respectively unlit and sunlit.

The outer contour 10 of the indicator 3 does not play a particular role and here presents approximately the shape of an 8. The shape represented in the drawings is chosen so as to minimize the space occupied by the indicator during its movement, while ensuring that the outline 10 will never be visible in the window 2. Line 12 visible in Figure 1 represents the outer limit of the area traversed by the indicator 3. Its shape makes it possible in particular to place the window 2 relatively close to the center 11 of dial 1, where the axes are usually located watch hands. As best seen in Figure 7, each of the zones 4 and 5 of the indicator comprises an approximately circular head 4a, 5a which is larger than window 2, in order to fully cover the area of this one to represent the new moon and the full moon, and a curved and tapered tail 4b, 5b whose minimum width from each point of the dividing line 6 is chosen so that the outline 10 does not appear in the window. At the border between the head and the tail, the greatest width of the tail is only slightly greater than the counter radius. The contour 10 has a re-entrant angle there which limits the area 12 covered by the indicator 3, especially in the vicinity of the center 11 of the dial.

As seen particularly in Figure 2, indicator 3 is supported and driven by a mechanism 14 mounted on a plate 13 with a movement watchmaking. The mechanism 14 comprises as input element a shaft 15 on which is fixed a rotary support plate 16 which extends below the indicator 3. The shaft 15 is rotatably mounted in the plate 13, by a bearing not represented, and it is driven by the clockwork movement so as to make two turns by lunation around its axis 17, that is to say in about 29.53 days. of the gear arrangements for obtaining such a period of revolution at from the hour wheel of a watch movement are well known and finds various variations in watchmaking literature, so it is not necessary to describe them here.

The indicator 3 is pivotally mounted around its axis 8 at a point off-center of the plate 16, for example by means of a ball bearing 18 which maintains the indicator in a position parallel to the plate. Axis 8 of the indicator is arranged so that its circular path around the axis 17, so also the trajectory of the central point C of the dividing line 6, passes through the axis 19 of the window 2 and therefore also through the center D (FIG. 7) of the window.

The mechanism 14 also comprises means for orienting the indicator 3 relative to the dial 1. In the preferred embodiment described here, these means are double and work alternately: first means of orientation keep indicator 3 in a constant orientation during a U-turn plate 16, while second orientation means block the pivoting of the indicator 3 on the plate 16 and therefore make it rotate with the latter during its second U-turn.

The first orientation means comprise a toothed wheel 20 fixed to the indicator 3, a toothed wheel 21 fixed to the plate 13 and a satellite mobile 22 having a shaft 23 rotatably mounted in the plate 16 by a ball bearing 24 so as to be able to rotate around its axis 25. The mobile 22 includes a wheel upper gear 26, permanently meshed on the wheel 20, and a gear lower 27 which meshes temporarily on the wheel 21. Indeed, the teeth of the wheel 21 extends only a little less than half the circumference, the remaining part 28 is smooth and recessed so as not to touch the wheel 27. The pitch diameters of toothed wheels 21 and 27 are equal, so that when the plate 16 makes a U-turn, for example in the direction of arrow A, the wheel 27 and therefore the mobile 22 make a U-turn in the same direction. Like wheels 20 and 26 also have equal diameters, the wheel 20 and the plate 3 make at the same time a U-turn in the opposite direction with respect to plate 16. When the latter performs a U-turn, the U-turn of the indicator in the opposite direction then has the effect that the indicator does not rotate relative to fixed elements such as dial 1 and the stage 13. In other words, the indicator then moves without changing orientation, in translating along the semi-circular path of its axis 8. At this moment, the wheel 27 arrives at the end of the toothing 21 and will be released from the latter at the during the second half-turn of the plate 16, during which the second means will act.

The second orientation means comprise a fixed cam 30, arranged between the fixed wheel 21 and the plate 13, and a rotary cam 31 which is part of the mobile satellite 22. The cam 30 has a substantially circular cam surface 33, centered on axis 17, the ends of which extend by two arcs 34 of smaller radius, between which the cam 30 has a recess 35. The cam 31 is formed by a disc in which are cut two symmetrical recesses forming cam surfaces 36 with the same radius as the surface 33 of the cam 30. The cam 31 has thus roughly the shape of a double ax, whose ends 37 can engage in the recess 35 of the cam 30 while the toothed wheels 21 and 27 are engaged.

When the toothed wheel 27 of the satellite mobile 22 emerges from the gear teeth 21, one of the cam surfaces 36 of the cam 31 is supported sliding on the cam surface 33 of the fixed cam 30. Thus, during the U-turn following the plate 16, the pivoting of the mobile 22 and of the indicator 3 on the plate 16 is blocked, so that the indicator rotates in a block with the plate. So he turns a half-turn with respect to dial 1 during the second half-turn of the stage. Then, the wheel 27 meshes again on the wheel 21 and the cycle begins again. Indicator 3 will again make a U-turn from the dial during the next full turn of the plateau 16.

The movements described above of indicator 3 during two turns of the plate 16, that is to say of a lunation, result in the positions represented in Figures 7 to 14. In these drawings, the dial 1 is assumed to be transparent for better to see the positions of the indicator, but in practice it is obviously opaque and an observer can only see the part of indicator 3 located behind the window 2 and forming an image of the different phases of the moon.

Figure 7 shows the new moon phase, where only the dark area 4 is visible in window 2. The center C of the indicator is then outside the window, as well as the entire dividing line 6. At this stage, the wheel 27 begins to mesh on the fixed wheel 21 and the indicator 3 will therefore move without rotate while its center C is moving as indicated by arrow B.

When the age of the moon reaches an eighth of the lunation, indicator 3 has the position shown in Figure 8 and it gives in window 2 the image of a crescent crescent moon. The indicator continues to move without rotating, until the first quarter shown in Figure 9. The section of the dividing line 6 which is then visible in the window 2 is substantially rectilinear, in accordance with the appearance real moon in the first quarter.

At this moment, the wheel 27 comes out of the wheel 21 and these are the cams 30 and 31 which will then control the orientation of the indicator 3, to rotate it as described above. This pivoting can be seen in Figure 10, which represents the growing gibbous moon, and continues to the full position moon shown in Figure 11, where we only see the light area 5 in the window 2, while the dividing line 6 is no longer visible.

From the full moon, the first means of orientation come into action to keep constant the orientation of indicator 3 in the gibbous moon phase decreasing, represented in figure 12, until the last quarter phase represented in figure 13. In the two figures 10 and 12 representing the moon Gibbous, we notice that the visible part of the dividing line 6 has a curvature conforms to reality and a shape that approaches the elliptical shape that we see in reality on the moon.

From the position of FIG. 13, the indicator 3 is again oriented by the second orientation means and will therefore make a U-turn until the phase of new moon shown in figure 7, passing through the position of figure 14 where its clear zone 5 is visible in the form of a crescent.

The foregoing description and the drawings show that the configuration of the moon indicator 3 and the movements imposed on it by the mechanism 4 display in window 2 images of the different moon phases which are very close to the real appearance of the moon.

In addition, the appearance of the displayed image is impeccable by the fact that the area dark and the light area of the image are in the same plane, immediately behind the opening of the dial. However, if we do not attach importance to this characteristic, it is possible to remove for example the dark zone 4 from indicator 3, which would then only have the shape of its light area 5, and give a dark color on the plate 16 which would then become visible in the window. Conversely, we could keep only the dark area of indicator 3 and give a light color on the tray 16.

In the embodiment shown, where the indicator 3 comprises the two zones 4 and 5, the plate 16 is never visible through the window and it could therefore be replaced by a smaller support element, sufficient to carry the bearings 18 and 24 relative to shaft 15.

We can conceive a simplified version of the mechanism described above, in which the indicator 3 would rotate regularly with respect to the dial throughout the lunation. It would be enough to remove the second means of orientation and replace the toothed wheels 21 and 27 by a pair of complete toothed wheels having a 1: 2 transmission ratio. However, such a system offers a less good agreement between the displayed image and the actual appearance of the moon over time, the variation of the displayed light area being too fast in certain phases and too slow in others.

We will now describe two other embodiments, in which the kinematics of indicator 3 can be substantially similar to that of the preferred embodiment, but is obtained by means of different mechanisms.

In the version illustrated by Figures 15 and 16, the indicator 3 carrying the zone dark 4, the light area 5 and the dividing line 6 has substantially the same shape than in the previous example and it is also pivotally mounted, in its center C, on the rotary support plate 16 by means of a shaft 43. The difference resides in the means of orientation of the indicator 3. This comprises on its face upper, along its outer contour, a sinuous rim 40 which serves as a cam and defines a slide 41 of constant width having an S trace. The underside of the dial 1 carries a fixed annular guide 42 situated around the periphery of the window 2 and engaged in the slide 41, the outside diameter of the guide being substantially equal to the width of the slide.

As in the previous example, the rotation of the plate 16 at a rate of two turns by lunation drives the center C of indicator 3 on a circular path 46 which passes through the center D of the window 2. The cam flange 40 sliding against the guide fixed 42 rotates the indicator 3 on the plate so that the movement of the indicator is similar to that described with reference to Figures 7 to 14.

In the version illustrated by Figures 17 and 18, the indicator 3 carrying the zone clear 5 and the dividing line 6 (the dark area has been omitted to clarify the drawing) has substantially the same shape as in the previous examples and it is also pivotally mounted, at its center C, on the rotary support plate 16. The indicator orientation means 3 are formed by a cam system different from that of the example of FIGS. 15 and 16, but producing substantially the same movements of the indicator.

At its center C, the indicator 3 comprises a shaft 50 which crosses the plateau of support 16, where it is mounted for example by a ball bearing. Below the plate 16, this shaft ends in a transverse arm 52 carrying two followers of cam formed by two pins 53 parallel to the shaft. These pins are engaged slidingly in a cam groove 55 formed in a fixed element, for example the plate 13. The layout of the groove 55, as seen in the drawing, is designed to produce the indicator movements described above, everything ensuring that the pins 53 follow the desired path when they pass through the crossing point 56 of the groove, but different paths are also possible. We could also provide two separate grooves, one for each pins. A single groove is sufficient here because the two pins 53 are arranged symmetrically with respect to the center C of the dividing line 6 and of the indicator.

We note that the orientation means of the last two examples include in each case two complementary bodies formed respectively by a cam and one or more cam followers, one of the organs being integral with the indicator and the other being fixed. This results in a great simplicity of the transmission mechanism that drives the indicator.

Claims (9)

Moon phase display device, in particular in a timepiece, comprising a dial (1) provided with a circular aperture (2), a mobile indicator (3) in the form of a plate, moving behind the dial and having a substantially S-shaped dividing line (6) between a dark area (4) and a bright area (5) which can be seen through the window, the indicator having a pivot axis (8) which passes by a center of symmetry (C) of the separation line, an input element (15) rotatably mounted on a plate and making a determined number of turns per lunation, and a transmission mechanism (14) ensuring a connection kinematics between the input element and the indicator,
characterized in that the transmission mechanism (14) comprises a rotary support (16) making two turns per lunation and the axis of rotation (17) of which is offset relative to the window (2),
in that the indicator (3) is pivotally mounted at a point on the rotary support (16) whose path passes through the center (D) of the window,
and in that said kinematic connection is arranged such that the indicator (3) makes one revolution per lunation with respect to the dial. Device according to claim 1, characterized in that the dark area (4) and the bright area (5) are both located on the indicator (3). Device according to claim 1 or 2, characterized in that the dark zone (4) and / or the light zone (5) each comprises or comprise a substantially circular head (4a, 5a), larger than the window (2), and a curved tail (4b, 5b) whose maximum width is approximately equal to the radius of the window. Device according to one of the preceding claims, characterized in that the separation line (6) comprises a substantially straight section (7) on which its center of symmetry (C) is located. Device according to one of the preceding claims, characterized in that the movement of the indicator (3) during a lunation comprises a first and a third step during which the indicator moves without substantially rotating relative to the dial, and a second and a fourth step during each of which the indicator moves by rotating substantially a half-turn relative to the dial. Device according to claim 5, characterized in that said kinematic connection comprises first gear orientation means (20 to 27), for maintaining the orientation of the indicator during said first and third stages, and second means for cam orientation (30, 31) for rotating the indicator with the rotary support during said second and fourth steps. Device according to claim 6, characterized in that the first orientation means comprise gears (20 to 27) which rotate the indicator by half a turn in one direction on the rotary support (16) while the latter ci makes a U-turn in the opposite direction. Device according to one of claims 1 to 5, characterized in that said kinematic connection comprises cam orientation means, comprising a fixed guide (42) disposed around the periphery of the window (2) and engaged in a sinuous slide ( 41) defined by a cam flange (40) on the indicator (3). Device according to one of claims 1 to 5, characterized in that said kinematic connection comprises cam orientation means, comprising at least one cam groove (55) formed in a fixed element and at least two cam followers ( 53) integral with the indicator (3) and slidably engaged in said one or more grooves.

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