CH719617B1 - Device for displaying discrete indications - Google Patents

Abstract

The invention relates to a device for displaying discrete indications for a timepiece movement, the display device comprising a dial (3), a first mobile and a second mobile pivoted with reference to the dial (3). The first mobile carries a first series of indications, the second mobile carries a revealer (2a, 2b), the device being arranged to rotate the first and second mobiles at the same angular speed with reference to the dial (3) during at least one phase of displaying an indication, the display device further comprising a phase shift mechanism capable of angularly offsetting the first and second mobiles between two display phases. The dial (3) is intended to partially mask the first and second mobiles, the dial (3) having an extended window (3a) capable of successively revealing the indications revealed by the superposition of an indication of the first mobile (1) with the revealer of the second mobile (2).

Description

Technical field

[0001] The present invention relates to a display device for a timepiece. It relates, more particularly, to a device for displaying discrete indications.

State of the art

[0002] There are many known examples of displaying discrete indications in watchmaking, starting with date displays. The time can also be displayed in digital form and the moon phases with a series of realistic images of the moon.

[0003] Application FR819282 describes a discrete time display: The hour indications are carried on disks pivoted on a dial itself pivoted with reference to the frame and rotated at a constant speed of half a revolution per hour. The indications appear successively in two openings arranged in the dial in a diametrically opposed manner. An external dial provided with a window extending over 180° makes it possible to make the opening containing the active indication visible and to mask the other opening. However, this type of display has a significant bulk both in thickness to ensure the guidance of the disks on the pivoting dial, and in the plane, which is almost entirely occupied by the mechanism, leaving only the possibility of a switch in the center to produce an additional display. In addition, the space available to carry the indications on the pivoted disks is limited, so that the indications have a limited size. Furthermore, the simultaneous display of two consecutive times when an hour passes, as shown in the first figure of application FR819282, introduces a risk of error in reading the time.

[0004] The third embodiment of application DE3918647 describes a discrete moon phase display in which moon images are formed using a lunar disk visible successively through twenty-eight different profiles of the moon cut out of an annular disk. The moon disk is rotated at a constant speed so that the position of the moon image on the periphery of the dial corresponds to the position of the moon in the sky. The profile ring is driven at the same speed for the duration of the display of a phase and is then instantly shifted by one twenty-eighth of a turn to display the next phase. However, reading information with this display mechanism can be misleading because the information appears upside down on the lower part of the dial. Anyone who plans nocturnal activity in a week by confusing the first and last quarters will end up with the new moon instead of the full moon and vice versa. Furthermore, a compromise must be made between the size of the images and their number, that is to say the fidelity of the phase represented.

[0005] Furthermore, the mechanisms for displaying discrete indications are often equipped with an instantaneous jump device allowing instantaneous passage from one indication to the next, as is frequently found in date mechanisms. Conventionally, these devices use jumpers, cams and springs and cause penalizing variations in the available driving torque. These mechanisms are generally designed to drive a mobile such as a date disc over a small angular travel and are not easily adaptable to achieve larger angular offsets.

[0006] The objective of the invention is to remedy the various drawbacks of the discrete indication display mechanisms of the prior art.

Disclosure of the invention

[0007] The object of the invention is achieved by a display device comprising a dial, a first and a second mobile pivoted with reference to the dial. the first mobile carries a first series of indications, the second mobile carries a first revealer. The device is arranged to rotate the first and second mobiles at the same angular speed with reference to the dial during at least one phase of displaying an indication. The display device further comprises a phase shift mechanism capable of angularly offsetting the first and second mobiles between two display phases. The dial is intended to partially mask the first and second mobiles and to allow the indications revealed by the superposition of an indication of the first mobile with a revealer of the second mobile to appear through an extended window.

[0008] This arrangement makes it possible to display large indications arranged around the perimeter of the dial and easily readable without risk of error.

[0009] According to an advantageous aspect, the first mobile is driven at constant speed and the phase shift mechanism is arranged to angularly shift the second mobile at the end of a display phase of an indication in order to reveal the following indication.

[0010] This arrangement allows the indications to appear and disappear instantly in the extended window to eliminate the risks of reading errors and loss of information.

[0011] According to an advantageous aspect, the indications are arranged according to the vertices of a star polygon, this particular arrangement making it possible to limit the amplitude of the angular shift during changes of displayed indications.

[0012] According to an advantageous aspect, the first mobile carries n series of indications arranged in concentric circles and the second mobile carries at least n revealers, each revealer being intended to reveal the indications of a series of indications.

[0013] This arrangement makes it possible to increase the surface area dedicated to the indications in order to display a large number of indications without reducing their sizes in proportion.

[0014] According to a particularly advantageous aspect of the invention, the phase shift mechanism comprises a first wheel intended to be driven at constant speed by the movement, a second wheel coaxial with the first wheel, intended to be kinematically connected to one of the first or second mobile, an elastic element arranged between the first and second wheels and tending to return the second wheel to a reference angular position relative to the first wheel, an input mobile intended to be driven by the movement and provided with discontinuous teeth arranged to mesh with the second wheel to drive it in rotation at a speed different from the first wheel during a period during which the elastic element accumulates energy, and arranged to temporarily disengage the second wheel to allow it to return to the reference angular position defined by the first wheel.

[0015] This arrangement allows instantaneous indication changes to be made with low and constant torque.

[0016] According to an advantageous aspect, the indications represent moon phases and the lower edge of the extended window symbolizing the horizon is horizontal or convex.

[0017] This arrangement makes it possible to reduce the duration during which the phase of the moon is not identifiable.

[0018] According to another advantageous aspect, at least one indication is always at least partially visible in the extended window.

[0019] This arrangement makes it possible to limit the loss of information and reading errors.

Brief description of the drawings

[0020] Other details of the invention will appear more clearly on reading the following description, given with reference to the appended drawings in which: – Figures 1 to 4 represent a first variant of a display according to the invention, – Figure 5 represents a kinematic diagram of a phase shift mechanism according to the invention, – Figures 6 to 10 represent different examples of dials of a moon phase display device according to the invention, – Figures 11 and 12 represent an advantageous variant of the display device of the invention before and after the transition from one image to the next, – Figures 13, 14 and 15 represent a variant of the display comprising two series of indications, – Figures 16 to 20 represent a first variant of a display comprising three series of indications, – Figures 21 to 25 represent a second variant of a display comprising three series of indications.

Embodiments of the invention

[0021] There are many known examples of discrete information displays in watchmaking, consisting of displaying a series of indications periodically. Date displays are the most common but different information can be displayed in this way such as digital time displays or moon phase displays. The indications are generally arranged in a circular manner on a disk or a ring as is also the case for the present invention. Other indication supports are possible such as rollers, movable flaps or strips but their height size limits their use for wristwatches. To distinguish the active image from those which are not, the display includes a revealer which can take different forms.

[0022] Application FR819282 presents a first type of revealer in the form of a window arranged in a dial positioned above a disk bearing time indications, making it possible to reveal the active indication and to hide the others. Generally speaking, the window can take the shape adapted to the indications to be revealed. It can just as well be a hollowed-out area as a translucent area revealing the indications of the first mobile.

[0023] Application DE3918647 presents a second type of developer consisting of a disk representing the visible face of the moon moving under an openwork annular disk bearing twenty-eight different profiles of the moon in order to form as many different images of the phases of the moon. The contrast between the profile through which the developer is visible and the other profiles makes it possible to reveal the active indication. In the same way as for the developer of the first type, the indications can be profiles cut out of the second mobile or translucent zones.

[0024] The different types of developers are equivalent and the term developer used throughout the application can take any appropriate form, in particular an opening in a second mobile positioned above a first mobile bearing indications or a developer placed on a second mobile itself arranged below a first mobile and visible successively through the different indications of the second mobile.

[0025] To enhance the contrast, the backgrounds of the first mobile and the second mobile may be of an identical color and texture. In all of the figures presented, the backgrounds of the first and second mobiles are gray. The edges of the window revealing the current hour digit in FIG. 3 are in reality barely visible, if at all. Similarly, for second-type developers, the background of the second mobile, identical to that of the first mobile, appears through the profiles of the inactive indications so that these indications are barely visible, if at all, and only the active indication to be displayed appears in a contrasting manner.

[0026] Figures 1 to 3 illustrate a first embodiment of a display of discrete indications according to the invention. Figure 1 shows a first mobile 1 in the form of an annular disk intended to be pivoted with reference to a dial 3 of the timepiece. A first series of indications 100 representing the hours from one to twelve is carried on the first mobile 1. The twelve indications are arranged in a circle according to the vertices of a star polygon {12/5} as illustrated in Figure 1. This arrangement makes it possible to move from one indication to another with a constant offset by going through all the indications in the series cyclically, returning to the first indication. Generally speaking, if n is the number of indications and p the step between two successive indications, each indication can extend over an angular sector of 360°/n, two successive indications being offset from each other by an angle 360°p/n. To form a star polygon of type {n/p}, the step p between two successive vertices must be chosen such that n and p have no common prime factor. The simplest star polygon is the pentagram and there is at least one star polygon for any integer n starting from seven. We could also arrange the successive indications contiguously according to the vertices of a convex polygon with p=1 but we will understand later that this arrangement is less favorable.

[0027] Figure 2 shows a second mobile 2 in the form of an annular disk intended to be pivoted with reference to dial 3 and which comprises two revealers 2a, 2b in the form of windows of a size slightly greater than that of the indications 100 of the first mobile 1. The second mobile 2 is intended to be placed coaxially with the first mobile 1 in order to mask the indications 100 of the first mobile with the exception of the indications located opposite the two revealers.

[0028] Figure 3 shows a view of a display according to the invention where the discrete indications are time indications. The display device comprises a dial 3 provided with an extended window 3a in the field of which the active indication moves. For this, the display device is arranged to rotate the first and second mobiles at the same angular speed during at least one phase of displaying an indication. In the embodiment presented, the indication of the current time is formed at the 9 o'clock position under the dial 3, then moves for one hour to the 3 o'clock position as shown in Figure 4. The second mobile is driven at the constant speed of half a revolution per hour, so that the two indicators 2a, 2b follow one another in the field of the window 3a. The change from one image to the next occurs when the two developers 2a, 2b occupy the 9 o'clock and 3 o'clock positions, hidden under the dial 3 as shown in FIG. 4. The first wheel set 1 is then instantly pivoted through an angle of 30° clockwise by a phase-shift mechanism 4 so that the next hour is positioned opposite the second developer 2b in the 9 o'clock position. FIG. 4 shows the display just before the switch between five and six o'clock. The two wheel sets then pivot jointly until the new hour reaches the 3 o'clock position and so on. It is preferable for the switch to take place under the dial 3 so as not to display two indications jointly, one of which would be erroneous, even if the risk of confusion seems limited in the case of the time display where two diametrically opposed indications are always six hours apart.

[0029] The phase shift value of 30° is the difference between the angular spacing of the indicators, i.e. 180°, and the angular spacing of two successive indications, i.e. 150°. If the successive indications were arranged contiguously every 30° on the first mobile, the angular phase shift value of 150° would be less favorable from an energy point of view.

[0030] The first and second mobiles could be slightly offset provided that the indicators remain superimposed on the indications in the display area corresponding to the extended window.

[0031] To facilitate reading the time, avoid the risk of confusion between the numbers 6 and 9 or free up the dial to produce other displays, it is possible to reduce the angular width of the window by increasing the number of indicators. The second wheel may, for example, have three indicators regularly spaced 120° apart and be driven at a speed of one third of a revolution per hour. The successive hour indications are then arranged at 150° in the anti-clockwise direction as in FIG. 11 and the phase shift value remains 30°.

[0032] When an indication is a time quantity, its movement during a display phase makes it possible to obtain information on a fraction of this time quantity. Thus, if the indication is the month of the year, the position of the month displayed can give the information on the date of the month. Similarly, the position of the date indication can give the time of day or the information on the minutes can give the second. In the embodiment presented, the position of the time displayed in the extended window 3a gives the information on the number of minutes elapsed in the current hour. To facilitate the reading of this information, the second mobile 2 and the dial 3 respectively comprise indicators 2i and an indication scale 3i. The indicators could also be placed on the first mobile 1 at the level of each of the indications 100.

[0033] In order not to lose the minute information during the few minutes before and after the time change during which the time indications are hidden, the shape of the window 3a can be adapted so that the indicators 2i remain visible at the 3 o'clock and 9 o'clock positions. An extension 3b of the window 3a, shown in FIG. 4, is provided for this purpose.

[0034] The angular offset between the first and second mobile is achieved by a preferably instantaneous phase shift mechanism 4. Many examples of such mechanisms are known, particularly in date displays. Conventionally, these mechanisms comprise cam or jumper systems with return springs which have the disadvantage of generating a significant and variable torque when they are actuated. This requires increasing the engine torque to the detriment of the power reserve to reduce the risk of untimely stopping in the event of joint actuation of another complication. Another disadvantage of these mechanisms is that they are designed to drive a date disc by a given angular amplitude using an actuator whose travel is limited. Commonly, they implement an actuator equipped with a pawl arranged to drive a mobile via a toothing. These mechanisms are not designed for variable and large amplitude movements.

[0035] The phase shift mechanism 4 of the present invention intends to remedy these drawbacks by proposing a low and constant resistive torque and a high adaptability of the phase shift angle. FIG. 5 represents a kinematic diagram of an exemplary embodiment of such a mechanism. The phase shift mechanism 4 comprises a first wheel 41 intended to be driven at constant speed by the movement as well as a second wheel 42, coaxial with the first wheel 41, and kinematically connected to an output wheel set 43. It will be understood subsequently that the output wheel set 43 can be one or the other of the first or second wheel sets 1, 2. An elastic element 44 is arranged between the first and second wheels 41, 42 and tends to return the second wheel 42 to a reference angular position relative to the first wheel 41. An input wheel set 45, intended to be driven at a continuous speed by the movement, is provided with discontinuous teeth 45d arranged to mesh with the second wheel 42 and drive it in rotation at a speed different from the first wheel 41. In the example of FIG. 5, the input wheel 45 also drives the first wheel 41 with a gear ratio different from the second wheel 42. As a result, the first wheel 41 and the second wheel 42 are angularly offset during a period which corresponds to one or more display phases of one or more indications during which the elastic element 44 accumulates energy. The angular offset of the first and second mobiles occurs when the second wheel 42 is opposite an interrupted sector of the discontinuous toothing 45d and disengages from the discontinuous toothing 45d. The second wheel 42 is then disengaged and is driven by the elastic element 44 to reach the reference angular position defined by the first wheel 41.

[0036] The reference position is obtained by a stop which angularly positions the second wheel 42 with reference to the angular position of the first wheel 41. The instantaneous change in position of the wheel 42 causes the instantaneous movement of the output wheel set 43 and therefore of one or the other of the first or second wheel sets in order to precisely position a revealer of the second wheel set 2 opposite a new indication of the first wheel set 1. Once the indication jump has been made, a portion of teeth of the input wheel set 45 meshes again with the second wheel 42 to ensure the joint movement of the first and second wheel sets while resuming the progressive offset of the first and second wheels. Even if the engagement of the second wheel 42 is not immediate after the jump, due to the minimum clearance necessary to ensure disengagement, the stop has the other function of momentarily driving the second wheel during the short transition period during which the second wheel is disengaged. This makes it possible to best adjust the size of the indicators to the size of the indications and to reduce the wasted space between the indications in order to prioritize the useful surface reserved for the indications. In the case of the secondary display of the minutes of the first embodiment presented, this also prevents the minute indicator from stopping when the hour passes.

[0037] The phase shift mechanism can be mounted in parallel between the movement and one of the first or second mobiles or in series between the two mobiles. In the latter case, the input wheel can be one of the first or second mobiles. Those skilled in the art will know how to adapt this mechanism to give it the desired characteristics. The output mobile 43 can be integral with the second wheel 42, the teeth can be internal or external. The interrupted toothing 45d can have several interruptions distributed regularly or irregularly depending on whether it is desired to obtain display durations of the indications and angular offsets that are equal or different as will be understood later. It is therefore particularly easy to adapt the different gear ratios to obtain the desired angular offsets.

[0038] Advantageously, the elastic element 44 may be a pre-stressed spiral spring working in an amplitude range where it has a substantially constant return torque. Furthermore, the phase shift mechanism of the invention does not contain a jumper or cam, so that the torque delivered by the elastic element can be extremely low in addition to being constant.

[0039] The device of the invention therefore makes it possible to produce a discreet display of indications which is easy to read, which does not present a consumption peak and which makes it possible to highlight a part of the movement or other displays in the central part of the dial.

[0040] Figures 6 to 10 illustrate another example of an embodiment of a display device according to the invention. Figure 6 shows a first mobile 1 on which eight indications 100 representing moon phases appear. The eight moon phases are distributed according to the vertices of an octogram {8/3}, two successive indications being separated by 135°. As in the preceding example, the display device comprises a second disk not shown carrying two diametrically opposed indicators and driven at a speed of four revolutions per lunation so that each of the eight phases is active for one eighth of a lunation where it moves from the 9 o'clock position to the 3 o'clock position. The phase change occurs under the dial 3 by an instantaneous rotation of 45° of the first mobile 1 in the counterclockwise direction.

[0041] In the case of a moon phase display, the loss of information during the phase change is particularly annoying. In the previous example of a discrete time display, the inability to read the time lasts about five minutes during which it is still possible to read the minutes. In the case of a moon phase display, the loss of information can last up to twenty-two hours for the example illustrated in FIG. 7. Each of the eight images of the moon occupies substantially an angular sector of 45° and travels half a dial revolution in one eighth of a lunation, or about 3.7 days. By convention, the moon is represented with a vertical terminator for the first and last quarters which approximates the image of the moon observable in the northern hemisphere. On the first mobile 1, the moon representations are oriented radially. In Figure 7, the lower edges of the extended window 3a also have a radial direction inclined at 22.5° relative to the horizontal so that the edge of the window is parallel to the terminator of the first and last quarters. As a result, in the position of Figure 7, after an angular displacement of 22.5° since the previous phase change, the active representation of the moon is still not identifiable: it may be the first quarter, the full moon or a gibbous moon. The same uncertainty occurs as soon as the image of the moon is half hidden under the right edge of the window. In total, the moon phase is not identifiable for a quarter of the display time of each phase, i.e. a little over twenty-two consecutive hours. Furthermore, no image appears in the extended window 3a for about five hours for a transition involving the full moon and for eleven hours in the other cases. Thus, at the rising of the last quarter or the last crescent, the moon begins to appear in the aperture after a movement of 22.5° or about eleven hours. The same disappearance of the moon occurs at setting for the first crescent and the first quarter. The extended aperture then presents a moonless sky so that it is impossible to distinguish a transition period from the display phase of the new moon.

[0042] The examples of FIGS. 8 to 10 partially overcome the drawback of the radial direction of the edges of the window of FIG. 7. Identification of the moon phase is possible when the terminator appears partially in the field of the extended window 3a. To reduce the duration of the loss of information, it is appropriate that the lower edge of the extended window 3a symbolizing the horizon line intersects the terminator as early as possible at moonrise and as late as possible at moonset. FIGS. 7, 8 and 9 represent the first quarter at moonrise. The radial direction of FIG. 7, parallel to the terminator, is the least favorable because it masks the terminator for the longest time. In FIGS. 8 and 9, the lower edge of the extended window symbolizing the horizon is respectively horizontal and convex, which limits the duration of the loss of information during transitions and, moreover, gives a more realistic appearance to the display than a concave horizon. In Figure 10 the profile of the lower edge of the extended window 3a is adapted to mask the indications at the time of the transition while limiting the duration of the loss of information.

[0043] Figures 11 and 12 show an advantageous embodiment that solves the problem of loss of information in the previous embodiment and the risks of reading errors in the prior art. A series of twelve indications 100, representing the hours, are arranged circularly on a first mobile according to the vertices of a star polygon {12/5}. A second mobile comprises two diametrically opposed indicators 2a, 2b. The first mobile is driven by the movement at a constant speed depending on the display time of an indication and the angular difference between two successive indications of the first mobile 1. In other words, the active indication will travel the angular difference separating it from the following indication during its display time. In the example shown, the successive indications are all arranged at 150° from each other and their display time is one hour. Consequently, the speed of the first mobile is 150° per hour, i.e. five revolutions in twelve hours. The second wheel carrying the indicators 2a, 2b is driven at the same speed for one hour so that a indicator 2a is superimposed on an indication of the first wheel and the active indication thus revealed moves in the extended window 3a. Only the one o'clock indication 101 in FIG. 11 and the two o'clock indication 102 in FIG. 12 are visible, the other indications shown in gray to facilitate understanding are in reality masked by the dial 3 or the second wheel 2. When the one o'clock indication 101 arrives in the 2:30 position shown in FIG. 11, i.e. 15° above the horizontal, the phase shift mechanism instantly shifts the second wheel by 30° clockwise, making the one o'clock indication 101 disappear and revealing the two o'clock indication 102 directly in the field of the extended window 3a as shown in FIG. 12.

[0044] In this embodiment, the shape and angular width of the extended window 3a are adapted to the arrangement of the indications on the first mobile and no longer to the number and size of the indicators of the second mobile as in the first embodiment. There is no longer any loss of information during the transition because an indication is always visible in the extended window. The risk of reading error of the prior art is also resolved because the extended window can be sized so that only one indication is visible at a time.

[0045] In this embodiment, the second wheel 42 of the phase shift mechanism described above is kinematically linked to the second wheel set 2. In the case where the first wheel set is driven at constant speed, it is also possible to use a retrograde mechanism to angularly shift the second wheel set which then only has one revealer. This retrograde mechanism can be inspired by the phase shift mechanism described above in which the first wheel is removed, the elastic element being placed between the second wheel and the frame in order to return the second wheel to a reference angular position relative to the frame. This reference angular position defines the position of the revealer at the time of the appearance of a new indication.

[0046] Generally speaking, for indications arranged according to the vertices of a star polygon {n/p}, it is interesting to choose the largest possible value of p on the one hand to limit the amplitude of the angular shift during changes of indications, on the other hand to increase the angular amplitude of the display of the indications and thus obtain a more extensive secondary indication scale. In the case of a moon phase display, this also makes it possible to give a dynamic representation of the movement of the moon in the extended window representing the sky.

[0047] The most common prior art moon displays comprise a disc carrying two moons driven at a speed of half a revolution per lunation. In its most ordinary embodiment, the moon disc is provided with a 59-tooth wheel driven by one tooth per day, making it possible to easily achieve a display period of 29.5 days. Since the duration of a synodic revolution of the moon is 29 days, 12 hours 44 minutes and 2.8 seconds, these displays need to be corrected regularly. To remedy this, some more sophisticated movements have a so-called "astronomical" moon display in which the moon disc is provided with a 135-tooth wheel driven by a 16-tooth wheel mounted on a 7-pointed star driven by a twenty-four-hour wheel. The display period thus obtained is 29 days 12 hours and 45 minutes generating a shift of only one day ahead in 122 years. However, the production of a 135-tooth wheel is not easy and this type of display remains rare.

[0048] The second embodiment in which the first mobile is driven at a constant speed makes it easier to produce an astronomical moon display. In this display, the different images of the moon are arranged according to the vertices of a star polygon {n/p} where n is the number of images and p is the pitch between two consecutive images. The angular difference between two consecutive images p*360°/n also corresponds to the angular amplitude of the movement of an active image. For n images, the total angular movement during a display cycle is p*360°, in other words the first mobile makes a number of revolutions equal to p during a display cycle. It is therefore easy to choose a number p divisor of 135 (p=3, p=5, p=9 or p=15) to produce an astronomical moon display by replacing the 135-tooth wheel with a 135/p-tooth wheel which is easier to produce. To obtain a continuous drive of the first mobile, the seven-tooth star of the intermediate mobile carrying the 16-tooth wheel is also replaced by a 10/35 reduction gear from the twenty-four-hour wheel or 10/70 from the twelve-hour wheel. By choosing a number of images n multiples of four to display the four characteristic phases, the most favorable combinations for producing an astronomical moon display are the following: {8/3}, {12/5}, {16/3}, {16/5}, {20/3}, {20/9}, {24/5}, {28/3}, {28/5}, {28/9}, {32/15}.

[0049] The discrete displays of the prior art in which the indications are arranged circularly on an annular disk, impose constraints between the number and the size of the indications. The moon phase display of the third embodiment of application DE3918647 has a disk bearing twenty-eight different moon images. The greater the number of images, the more faithful the image represented by the display is to the appearance of the moon observable in the sky, but the smaller this image is. It is therefore necessary to make a compromise between the size of the indications and the precision of the information provided by the display. An aim of the present invention is not to make any compromises and to produce a display of discrete indications which presents a large number of indications without having to reduce the size of these indications in proportion.

[0050] This aim is achieved by means of a first mobile 1 comprising a plurality of series of indications arranged according to concentric circles of distinct radii centered on the axis of rotation of the first mobile. FIGS. 13 to 15 give a first example of a discrete display of moon phases implementing this advantageous aspect of the invention. FIG. 13 illustrates a first mobile 1 carrying a first series of indications 100 arranged on an inner circle as well as a second series of indications 200 arranged on an outer circle, each comprising eight representations of the moon. Two consecutive moon phases do not belong to the same series of indications and are arranged at 157.5° from each other according to the directions of the vertices of a star polygon {16/7}.

[0051] Figure 14 illustrates a second mobile 2 comprising a first developer 2a and a second developer 2b intended to reveal respectively the indications of the first series of indications 100 and of the second series of indications 200. To optimize the useful surface dedicated to the indications, the shape of the developers 2a, 2b is adjusted to the shape of the indications, for example a circular shape for moon phases or an annular section shape for alphanumeric indications.

[0052] Figure 15 shows a dial 3 provided with an extended window 3a in which appears an image of the last quarter 101 formed by the superposition of the first revealer 2a of the second mobile 2 with an indication of the first series 100 of the first mobile 1. The display is shown just before a change of indications, after the active moon phase has described an arc of a circle of 157.5° centered on the twelve o'clock position in the extended window 3a. Immediately thereafter, the phase shift mechanism shifts the second wheel set 2 by an angle of 22.5° clockwise to superimpose the second revealer 2b with the next indication 201 of the second series and make it appear on the left of the extended aperture 3a while the image of the last quarter 101 disappears following the movement of the first revealer 2a under the dial 3. The first and second wheel sets 1, 2 are then driven together for 157.5° before a new shift of the second wheel set causes the next indication of the first series to appear. This embodiment makes it possible to increase the surface area available for the indications in order to produce a discrete display comprising a large number of indications without having to reduce their size. In the case of a moon phase display, this configuration makes it possible to produce a dynamic display which is renewed frequently and in which the images of the moon, as in reality, appear and disappear at different locations on the horizon and rise more or less high above the horizon.

[0053] The use of multiple series makes it possible to produce a discrete display comprising a large number of indications, for example a digital display of the minutes distributed according to two series of thirty indications, three series of twenty or four series of fifteen. Each indication of the same series is positioned at the same distance from the axis of rotation of the first mobile which is also the distance between the axis of rotation of the second mobile and the revealer(s) corresponding to this series.

[0054] Figures 16 to 25 illustrate two examples of a discrete moon phase display using a first mobile 1 comprising twenty-four indications distributed in three series of eight as shown in Figure 16. The display sequence takes place in a predefined order: the first indication of the first series 101 is followed by the first indication of the second series 201, then the first indication of the third series 301, then the second indication of the first series 102 and so on up to the eighth indication of the third series 308 before returning to the first indication of the first series 101. Unlike the previous displays presented, the angular difference between two consecutive indications is not constant. It is 112.5° between two consecutive indications of the first and second series as well as between two consecutive indications of the second and third series and it is only 90° between two consecutive indications of the third and first series.

[0055] Figure 17 illustrates a second mobile 2 arranged so that the angular offset only occurs when changing from an indication of the third series to an indication of the first series according to the steps illustrated in Figures 18 to 20. To this end, the second mobile 2 comprises a first, a second and a third revealer 2a, 2b, 2c arranged with the same angular distance as three successive indications 101, 201, 301 of the first mobile 1. Thus when the first revealer 2a is superimposed with the first indication of the first series 101, the second and third revealers 2b, 2c are respectively superimposed on the first indications of the second and third series 201, 301.

[0056] Figure 18 illustrates a transition between the display of an indication of the first series 101 and that of an indication of the second series 201. The transition is carried out continuously without there being any angular offset between the first and second moving parts. The size and shape of the extended window are freely adapted either to see only one moon image at a time in the extended window, or to minimize the loss of information by making the next image appear before the current image disappears.

[0057] Figure 19 shows the display during the transition between an indication of the second series 201 which gradually disappears under the right edge of the window and an indication of the third series 301 which appears under the left edge of the window.

[0058] Figure 20 shows the display just before an instantaneous transition between an indication of the third series 301 and the next indication of the first series 102 which is effected by an angular shift of the second mobile 2 of 45° in the clockwise direction so that the first revealer 2a is superimposed on the next indication of the first series 102 to reveal it. Unlike the previous embodiments presented, the phase shift mechanism is not triggered at each transition but only once out of three.

[0059] To illustrate the great freedom of design of the display mechanisms of the invention, FIGS. 21 to 25 represent a variant of the preceding display which uses a mobile 1 comprising three series of eight indications arranged in the same locations but in a different order. The first series of indications 101, 102 is arranged on the outer circle while the third series 301, 302 is arranged on the inner circle.

[0060] Figures 23 to 25 illustrate the display just before the transitions caused by the angular offsets of the second mobile 2. The indications of the first, second and third series appear in the extended window on the same radial line inclined at approximately 40° above the horizontal. The lower edge of the extended window symbolizing the horizon has a profile designed so that there is always one and only one indication at least partially visible and so that the terminator of this indication is always at least partially visible in order to allow the active phase to be identified. As can be seen in Figures 23 and 24, each indication of the first and second series 101, 201 travels an angle of 112.5° in the extended window before giving way to the following indication. An indication of the third series 301 only travels through an angle of 90° before being replaced by the next indication of the first series 102 as shown in FIG. 25. In the case where the phase shift mechanism presented above is used, the value of the phase shift angle is proportional to the duration and the angular amplitude of display of the active indication. This value is therefore 112.5/90=1.25 times greater after the display of an indication of the first or second series than after that of an indication of the third series. As can be seen in FIG. 21, the sum of three successive shifts allowing to pass from one indication to the next indication of the same series has a value of 45° which is broken down into two shifts of 16.071° (5/14 of 45°) and a shift of 12.857° (2/7 of 45°).

[0061] From these values, the angular position of the first, second and third indicators 2a, 2b, 2c on the second mobile 2 as shown in FIG. 22 is deduced. It is obviously possible to use another type of phase shift mechanism causing, for example, a shift of a constant value of 15° between two successive indications. In this case, the second and third indicators 2b, 2c would be arranged respectively at 127.5° and 105° from the first indicator 2a.

[0062] It may be noted that the size of the indications may vary from one series to another in order to optimize the total useful surface area devoted to the indications. A person skilled in the art will be able to combine the various features presented in the exemplary embodiments in order to produce a wide variety of discrete indication displays without departing from the scope of the invention.

[0063] The invention is composed of three essential elements which are the dial and the two mobiles. In the examples presented, the dial is fixed relative to the frame of the timepiece and the mobiles have been defined as pivoted in the frame of reference of the dial. It is entirely possible, without departing from the scope of the invention defined by the main claim, that in the frame of reference of the timepiece, one of the mobiles is fixed while being pivoted with reference to the dial which would itself be mobile in rotation in the frame of reference.

Claims (10)

1. A device for displaying discrete indications for a timepiece movement, the display device comprising a dial (3), a first mobile (1) and a second mobile (2) pivoted with reference to the dial (3), the first mobile (1) carrying a first series of indications (100), the second mobile (2) carrying a first revealer (2a), the device being arranged to rotate the first and second mobile (1, 2) at the same angular speed with reference to the dial (3) during at least one display phase of an indication, the display device further comprising a phase shift mechanism capable of angularly offsetting the first and second mobile between two display phases, characterized in that the dial (3) is intended to partially mask the first and second mobile, the dial (3) having an extended window (3a) capable of successively revealing the indications revealed by the superposition of an indication of the first mobile (1) with the revealer of the second mobile (2). 2. Device according to claim 1 in which the first and second mobiles (1, 2) are coaxial. 3. Device according to the preceding claim, in which the phase shift mechanism comprises: – a first wheel (41) intended to be driven at constant speed by the movement, – a second wheel (42) coaxial with the first wheel, intended to be kinematically connected to one of the first or second mobile, – an elastic element (44) arranged between the first and second wheels (41, 42) and tending to return the second wheel (42) to a reference angular position relative to the first wheel (41), – an input mobile (45) intended to be driven by the movement and provided with discontinuous teeth (45d) arranged to mesh with the second wheel (42) to drive it in rotation at a speed different from the first wheel (41) during a period during which the elastic element (44) accumulates energy, and arranged to temporarily disengage the second wheel (42) to allow it to reach the reference angular position defined by the first wheel (41). 4. Device according to one of the preceding claims, in which the first mobile (1) is driven at constant speed with reference to the dial (3) and in which the phase shift mechanism angularly shifts the second mobile (2) at the end of a display phase of an indication in order to reveal the following indication. 5. Device according to the preceding claim in which the phase shift mechanism is a retrograde mechanism. 6. Device according to one of claims 1 to 5 in which the second mobile (2) comprises at least two developers (2a, 2b). 7. Device according to one of the preceding claims in which at least one indication is always at least partially visible in the extended window. 8. Device according to one of the preceding claims in which the indications are arranged according to the vertices of a star polygon. 9. Device according to one of the preceding claims in which the indications represent moon phases and in which the lower edge of the extended window symbolizing the horizon is horizontal or convex. 10. Device according to one of the preceding claims, in which the first mobile (1) carries at least two series of indications arranged in concentric circles of distinct radii and in which the second mobile (2) carries at least two revealers, each revealer being intended to reveal the indications of a series of indications.