System for displaying time-of-day functions and chronograph

Abstract

The invention relates to a display system for a mechanical timepiece comprising a watch movement to provide a current time function, at least one sub-assembly (121) coupled to the watch movement to provide a chronograph function allowing the same time value to be alternately displayed by means of a single indicator for each of the current time and chronograph functions, said at least one sub-assembly (121) comprising a phase-shift tracking mechanism (123) arranged to mechanically monitor the angular offset between a driving wheel of the watch movement and a driven wheel of said at least one sub-assembly (121) allowing the driven wheel, controlling the movement of the single indicator, to be moved, when switching from the chronograph function to the current time function, according to said angular offset so that the single indicator displays the current time function.

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a mechanical display system for a time value, such as seconds, minutes or hours, for a current time function and a chronograph function. TECHNICAL BACKGROUND OF THE INVENTION

[0002] Typically, the mechanical display of the current time is separate from the mechanical chronograph display. Sub-dials or auxiliary dials and hands dedicated to the chronograph function are arranged around the center of the dial, while the current time is displayed with an hour ring around the periphery of the dial and other dedicated hands. The dial is therefore quite busy and can be difficult to read, i.e., to interpret. SUMMARY OF THE INVENTION

[0003] The invention aims to provide a display system combining current time and chronograph functions, the reading of which is greatly simplified.

[0004] To this end, the invention relates to a display system for a mechanical timepiece comprising a mechanical watch movement arranged to measure time, a function called current time, allowing the display of at least one time value using an indicator, characterized in that the display system comprises at least one sub-assembly coupled to the watch movement and comprising a control mechanism for selectively measuring a duration, a function called chronograph, allowing said same time value to be alternately displayed using a single indicator for each of the current time and chronograph functions, and in that said at least one sub-assembly comprises a phase-shift tracking mechanism arranged to mechanically monitor the angular offset between a driving wheel of the watch movement and a driven wheel of said at least one sub-assembly, allowing the driven wheel, controlling the movement of the single indicator, to be moved.During the transition from the chronograph function to the current time function, according to said angular offset, the single indicator displays the current time function.

[0005] Advantageously, according to the invention, the display system is mechanically capable of displaying, with the same indicator, the same time value for both a current time function and a chronograph function. Thus, according to an advantageous operation, the display system according to the invention is capable of switching between a current time function, displaying, for example, using at least one indicator, a time value such as hours, minutes, or seconds, the usual counting value of the finishing gear of the watch movement, and a chronograph function, displaying, with the same indicator, the value of a chronograph count obtained with the display system according to the invention. It is therefore very simple to read the time value because it is always displayed by the same indicator, whether the display system is in current time or chronograph mode.

[0006] Ingeniously, the display system does not use a standalone sub-module for the chronograph function. Instead, it employs a phase-tracking mechanism between a driven wheel that moves the single indicator (which is therefore not, as is usually the case, a wheel from the watch movement's finishing gear train) and a driving wheel from the finishing gear train. This mechanically compensates for any angular misalignment between the driven and driving wheels when the chronograph function is in use. Thus, when switching from the chronograph function to the current time display, the angular misalignment is mechanically transferred from the phase-tracking mechanism to the driven wheel, which then displays the time value from the watch movement's finishing gear train.

[0007] The invention may also include one or more of the following optional features, taken alone or in combination.

[0008] The phase-shift tracking mechanism may include a differential device mounted between the driving and driven wheels, designed to memorize any angular shift between them when the chronograph function is active. This differential device allows the finishing gear train to operate normally by independently controlling the movement of the driven wheel during chronograph operation. The driven wheel can therefore be stopped or moved as needed to achieve the desired reading on the single indicator during chronograph function.

[0009] The differential device includes an epicyclic gear train mounted between a first wheel and a second wheel, the first wheel being connected to the driven wheel and the second wheel being connected to the driving wheel, the epicyclic gear train being arranged to memorize the differential rotation angle between the driving wheel and the driven wheel when the chronograph function is active and to reproduce this phase shift when switching from the chronograph function to the current time function so that the single indicator displays the current time function.

[0010] Advantageously, according to the invention, in chronograph mode, the single indicator, although potentially angularly out of phase with the driving wheel, can be moved during timing by the driving wheel belonging directly or indirectly to the finishing gear train. The angular offset is thus stored by the phase-tracking mechanism while the chronograph function is transparently displayed for the user. Furthermore, each time the chronograph function is stopped, the phase-tracking mechanism monitors and mechanically increments any angular offset, without the single indicator changing position. Finally, when the user switches from the chronograph function to the current time function, the epicyclic gear train mechanically restores the recorded angular offset by transferring it to the driven wheel so that the single indicator displays the current time function.

[0011] The differential device can be controlled by a cam-hammer assembly driven by the control mechanism and arranged to restore the stored angular offset to the driven wheel when the hammer strikes the cam, so that the single indicator displays the current time. Similar to a chronograph reset mechanism (but with a different function), the hammer forces the cam (for example, heart-shaped) to return to the angular orientation of the driving wheel, which, thanks to the differential device, mechanically transfers the stored angular offset to the driven wheel, allowing the single indicator to display the current time.

[0012] Said, at least one subassembly, may include a device for locking the driven wheel, controlled by the control mechanism, so that the single indicator displays a fixed chronograph function counting position. To achieve the chronograph function stop mode, the locking device acts on the driven wheel to lock it and, incidentally, induce an angular shift between the driven wheel and the driving wheel. This angular shift is then immediately detected and mechanically stored by the phase-shift tracking mechanism.

[0013] The locking device may include at least one locking stop arranged to move between a locked position to prevent any movement of the driven wheel and a non-locking position in which the driven wheel is free from any constraint of the locking device. When the chronograph function is stopped, the locking device acts directly on the driven wheel to render the single indicator static. Advantageously, according to the invention, said at least one bistable locking stop (two stable positions) simply allows the chronograph function to be started (non-locking position) or stopped (locking position).

[0014] The driven wheel can be controlled by a cam-hammer assembly driven by the control mechanism and arranged to move the driven wheel to a predetermined angular position when the hammer strikes the cam, so that the single indicator displays a starting value for the chronograph function. In addition to the locking device, the display system can therefore, upon activation of the chronograph function, position the single indicator at a predetermined starting position (for example, at twelve o'clock using the cam-hammer assembly) and hold it stationary (using the locking device) until the user initiates the counting.

[0015] This at least one time value can be the hour or the minute. One can imagine, in particular, a first subset dedicated to displaying minutes using a single indicator and / or a second subset dedicated to displaying hours using a second single indicator. Of course, other time values ​​such as the second can be considered without departing from the scope of the invention.

[0016] Finally, the invention also relates to a timepiece characterized in that it comprises the display system as described above. More specifically, the timepiece may comprise a first subset in which the time value is the minute and a second subset in which the time value is the hour. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features and advantages of the invention will become clear from the description given below, which is by way of example and in no way limiting, with reference to the attached drawings, in which: there figure 1 is a schematic view of an example of a timepiece; the figures 2 and 3 These are top and bottom perspective views of an example of a watch movement with a display system; figures 4 to 7 are views of an example of the first subset of the seconds of the display system; the figures 8 to 10 are cross-sectional, top, and bottom views of an example of the second subset of the display system's minutes; figures 11 to 12 are top and bottom views of an example of the third subset of the display system's hours; the Figures 13 to 14 are top and bottom views of an example of a safety device for the control mechanism in the active position of the chronograph function; the Figures 15 to 16 are top and bottom views of an example of a safety device from the second subassembly; the f figures 17 to 18 are views of an example variant of the first subset of seconds in the display system; the figure 19 is a top perspective view of an example variant of the second and third subsets of the display system. DETAILED DESCRIPTION OF AT LEAST ONE EMBODIMENT OF THE INVENTION

[0018] In the various figures, identical or similar elements bear the same references, possibly with an additional subscript. Therefore, a description of their structure and function is not systematically repeated.

[0019] In all that follows, orientations are the orientations of the figures. In particular, the terms "upper", "lower", "left", "right", "above", "below", "forward" and "backward" are generally understood in relation to the direction in which the figures are represented.

[0020] In everything that follows, orientation terms are understood with respect to the orthogonal coordinate system shown on the figure 1 and in which we can distinguish: a longitudinal axis X, horizontal extending from back to front; a transverse axis Y, horizontal extending from left to right; and a vertical axis Z, extending from bottom to top.

[0021] The term "horizontal" is defined in relation to the XY plane (direction parallel to the main section of the 3A plate of the watch movement), the terms "vertical plane" are defined in relation to a horizontal component projected along the vertical axis Z (direction perpendicular to the horizontal direction and parallel to the thickness of the 3A plate of the watch movement 3).

[0022] By "fixed part" we mean all the elements or components fixed relative to the given reference frame such as, for example, relative to the 3A plate, i.e. static relative to the 3A plate or the 3A plate itself.

[0023] By "horological component 2", we mean all types of timekeeping or measuring instruments such as clocks, small clocks, watches, etc...

[0024] By "watch movement 3", we mean all types of mechanisms capable of counting time whether they are powered by mechanical energy (e.g. a barrel) or electrical energy (e.g. a battery).

[0025] By "value of a current time function," we mean the value of the clock movement's count 3, i.e., for example, the hours and / or minutes and / or seconds. In the example illustrated in the figure 1, there is a 5A hour indicator, a 5B minute indicator and a 5C second indicator intended to display three values ​​of the current time function of the watch movement 3.

[0026] By "value of a chronograph function" is meant the value of the on-demand counting of a duration by a display system 1 of the watch movement 3, i.e., for example, hours and / or minutes and / or seconds. In the example illustrated in the figure 1 , it is planned to use the same indicators 5A for hours, 5B for minutes and 5C for seconds to display the three values ​​of the chronograph function of the watch movement 3 using the display system 1.

[0027] In the example illustrated in figures 2 and 3We can see a watch movement 3 intended to be integrated into a timepiece 2, such as a wristwatch. The watch movement 3 preferably comprises an oscillator 4 with a balance-spring type resonator and a Swiss lever escapement. Since such an oscillator 4 is known to those skilled in the art and is not essential to the present invention, it will not be described further. Similarly, the watch movement 3 also comprises, in a known manner, a finishing gear 9, a correction mechanism (controlled by the crown 8A located at three o'clock), and preferably a self-winding mechanism.

[0028] In the example of figures 2 and 3The display system 1 is advantageously designed to use the same hour indicators 5A, minute indicator 5B, and second indicator 5C to alternately display the three values ​​of the chronograph function or the three values ​​of the current time function. Of course, the display system 1 could include fewer indicators, such as only one hour indicator 5A, only one minute indicator 5B, only one second indicator 5C, or even only minute and second indicators 5B and 5C, without departing from the scope of the invention.

[0029] The display system 1 is thus a mechanism semi-integrated into the watch movement 3. According to an advantageous operation, the display system 1 is able to switch between a current time function (by pressing the control organ 8B located at ten o'clock) displaying, in the example illustrated with the use of the hour indicators 5A, minute indicator 5B and second indicator 5C, the usual counting value of the finishing gear 9 of the watch movement 3, and a chronograph function (by pressing the control organ 8C located at four o'clock) displaying, in the example illustrated with the use of the hour indicators 5A, minute indicator 5B and second indicator 5C, the value of a chronograph function count obtained with the display system 1.

[0030] More specifically, after activating the chronograph function by pressing the control organ 8C located at four o'clock (the hour indicators 5A, minute indicator 5B and second indicator 5C all move to twelve o'clock), the user can start the time counting on demand (chronograph function) by pressing the control organ 8D located at two o'clock once and stop the time counting on demand (chronograph function) by pressing the same control organ 8D located at two o'clock a second time.

[0031] When the on-demand time display (chronograph function) is no longer needed, the user presses the control element 8B located at ten o'clock to display the usual counting value of the finishing gear 9 of the watch movement 3. In other words, regardless of the time measurement performed in chronograph function, the hour indicator 5A, minute indicator 5B, and second indicator 5C resynchronize with the values ​​of the finishing gear 9. It is then understood that the chronograph function values ​​can no longer be displayed, and pressing the chronograph function control element 8C located at four o'clock resets the hour indicator 5A, minute indicator 5B, and second indicator 5C to twelve o'clock, ready for another on-demand time measurement (chronograph function).

[0032] It is therefore understood that the display system 1 is a mechanism of three independent sub-assemblies 21, 121, 221, each coupled to a wheel preferably distinct from the finishing gear 9 in order to allow alternative switching between the current time function and the chronograph function by displaying, in the illustrated example, the values ​​with the same indicators 5A for hours, 5B for minutes and 5C for seconds.

[0033] In the example illustrated in figures 4 to 7 , a first subset 21 of the display system 1 is presented. The first subset 21 concerns the alternative display of the seconds of the current time function or the chronograph function by the same indicator 5C (a central hand in the example of the figure 1The first subassembly 21 mainly comprises a selective coupling mechanism 23, a locking device 29, and a control mechanism 25 to allow switching on demand between the current time function and the chronograph function (and between the two modes, i.e., start and stop, of the chronograph function). The first subassembly 21 of the display system 1 is intended to be coupled to a driving wheel 22 of the watch movement 3, enabling the counting of seconds for the current time function. In the example illustrated in figures 4 to 7 , the leading wheel 22 is the seconds wheel of the finishing gear 9 of the watch movement 3.

[0034] The selective coupling mechanism 23 mainly comprises a chronograph seconds wheel 27 and a clutch device 31. Preferably, the single seconds indicator 5C is fixed to the chronograph seconds wheel 27 (hand driven onto one end of a pivoting shaft 27A of the wheel 27 in the example of the figure 4 ). The chronograph seconds mobile 27 comprises a driven wheel 27B coupled to the driving wheel 22, via the shaft 27A, by a first cam 32 - first cam 32 follower 33 assembly and a friction spring 34.

[0035] More precisely, similarly to a catching mechanism, the follower 33 of the first cam 32 includes a lever 33A elastically constrained by an elastic element 33B (coil spring in the example of the figures 4 to 7 ) against the peripheral surface of the first cam 32 (heart-shaped in the example of the figures 4 to 7). The first cam 32 is thus fixedly mounted on the shaft 27A and the follower 33 of the first cam 32 is pivotally mounted on the driving wheel 22 (freely mounted in rotation relative to the shaft 27A).

[0036] Therefore, free from any constraint, the lever 33A, elastically pressed against the peripheral surface of the first cam 32, will move the first cam 32 to find the unique predetermined stable position of the first cam 32 - first cam follower 33 assembly (double base surface of the peripheral surface of the core 32 stably receiving the contact surface of the lever 33A in the example of figures 4 to 7Conversely, lever 33A, elastically pressed against the peripheral surface of the first cam 32, will move relative to the first cam 32 (sliding of the contact surface of lever 33A against the peripheral surface of the heart 32) if a relative movement is applied between the driving wheel 22 and the driven wheel 27B so that the seconds indicator 5C can display a value different from that of the driving wheel 22 (the seconds wheel of the finishing gear train 9 in the example illustrated in figures 4 to 7 ).

[0037] Advantageously, this configuration allows, without any other constraints, the driven wheel 27B to be synchronized with the rotation of the driving wheel 22. Thus, when the current time function is activated by pressing the control element 8B located at ten o'clock, the wheel 27B is synchronized with the driving wheel 22 so that the single indicator 5C displays the value of the current hour seconds, that is to say, it copies the rotation angle of the seconds wheel of the finishing gear 9 in the example illustrated in figures 4 to 7 .

[0038] As more clearly seen in the cross-sectional view of the variant of the figure 6The chronograph seconds wheel 27 comprises five levels, one above the other. More precisely, a first, lower level is formed by the driving wheel 22. A second level (located above the first level) comprises the first cam 32 - first cam follower 33 assembly. A third level (located above the second level) is formed by a second cam 35 (heart-shaped) (rotationally fixed to the first cam 32), which will be explained further below. A fourth level (located above the third level) is formed by the friction spring 34 (comprising an annular central hub mounted around the shaft 27A and four elastic arms extending radially from the outer diameter of the hub to the underside of the driven wheel 27B in the example of the figures 4 to 7 ) allowing the movement of the second cam 35 to be linked, below a predetermined constraint, with that of the driven wheel 27B located in the fifth level.

[0039] The locking device 29 mainly comprises a rocker 37 equipped with a stop 37A for locking the driven wheel 27B. The locking device 29 is arranged to move the rocker 37 between a locked position to prevent any movement of the driven wheel 27B, and a non-locking position in which the driven wheel 27B is free from any constraint of the locking device 29. Typically, as will be explained in more detail below, when the current time function is activated by pressing the control element 8B located at ten o'clock, the locking device 29 is arranged to force the rocker 37 into the non-locking position so that the single indicator 5C displays the value of the seconds of the current hour, i.e., copies the rotation angle of the seconds wheel of the finishing gear 9 in the example illustrated in figures 4 to 7 .

[0040] Furthermore, the locking device 29 is arranged so that, in the locked position, the rocker 37 pivots until the locking stop 37A is against the driven wheel 27B in order to prevent any movement of the driven wheel 27B. Typically, as will be explained in more detail below, when the chronograph function is activated by pressing the control organ 8C located at four o'clock, the rocker 37 in the locked position allows the single seconds indicator 5C to display a fixed value for the chronograph seconds.

[0041] It is understood that in the stationary position of the rocker arm 37, the driving wheel 22 and the driven wheel 27B will be able to move relative to each other. However, advantageously, the relative movement of the driving wheel 22 with respect to the driven wheel 27B is stored by the first cam 32 - first cam follower 33 assembly. In other words, the first cam 32 and the first cam follower 33 allow the phase shift between the driving wheel 22 and the driven wheel 27B without desynchronization.

[0042] Typically, when the current time function is activated by pressing the control element 8B located at ten o'clock, the locking device 29 is arranged to move the rocker 37 to its unlocked position so that, via the first cam 32 - first cam follower 33 assembly, the driving wheels 22 and driven wheels 27B resynchronize as already explained above, so that the single indicator 5C again displays the current time seconds value, i.e., copies the rotation angle of the seconds wheel of the finishing gear 9 in the example illustrated in figures 4 to 7 .

[0043] The clutch device 31 is designed to selectively allow the driven wheel 27B to be driven in rotation in conjunction with the driving wheel 22 so that the single seconds indicator 5C displays a chronograph function seconds count by the movement of the driving wheel 22. The clutch device 31 primarily comprises a lever 39 and an oscillating double pinion 41. The clutch device 31 is arranged to move the double pinion 41 between an engaged position (upper pinion 41A meshed with the driven wheel 27B) and a disengaged position (upper pinion 41A disengaged from the driven wheel 27B), the lower pinion 41B being permanently coupled with the driving wheel 22. In the example illustrated in figures 4 to 7The oscillating double pinion 41 is mounted in a tilting manner, that is to say, guided in oscillation between a recess in a fixed part of the watch movement 3 and the lever 39. In addition, as will be better explained below, the lever 39 is mounted pivoting between engaged and disengaged positions in order to move the double pinion 41.

[0044] More precisely, in the disengaged position of lever 39, the clutch device 31 is arranged to move the upper pinion 41A away from the double pinion 41 of the driven wheel 27B, thus freeing it from any constraint. Typically, as explained above, when the current time function is activated by pressing the control element 8B located at ten o'clock, the clutch device 31 is arranged to force the disengaged position of the double pinion 41 so that the single indicator 5C displays the value of the current hour seconds, i.e., it copies the rotation angle of the seconds wheel of the finishing gear 9 in the example illustrated in figures 4 to 7 .

[0045] Furthermore, the clutch device 31 is arranged so that, in the engaged position, the lever 39 pivots until the upper pinion 41A of the double pinion 41 meshes with the driven wheel 27B, thus coupling the movement of the driven wheel 27B to that of the driving wheel 22. Typically, as will be explained in more detail below, when the chronograph function is activated by pressing the control organ 8D at two o'clock for the first time, the clutch device 31 is arranged to force the lever 39 into its engaged position so that the single seconds indicator 5C displays a chronograph seconds count by the movement of the driving wheel 22.

[0046] Finally, the control mechanism 25 of the display system 1 allows, in particular, the control of sub-assemblies such as the functions of the first sub-assembly 21 of the seconds. The control mechanism 25 mainly comprises a hammer 43 - second cam 35 assembly of the seconds, a column-mounted mobile 25A, the control organ 8B of the current time function (located at ten o'clock on the timepiece 2), the control organ 8C of the chronograph function (located at four o'clock on the timepiece 2) and the control organ 8D of the start / stop of the chronograph function counting (located at two o'clock on the timepiece 2).

[0047] The control elements 8B, 8C, 8D are preferably mounted, under elastic tension, in a protruding position on the case of the timepiece 2. When the user presses elements 8B, 8C, 8D, they must first overcome a detent to begin moving the element, then overcome the elastic tension to bring the element to the depressed position and thus activate the dedicated function. When the user releases element 8B, 8C, 8D, it returns to the protruding position due to the elastic tension, and the detent is relocked. As explained below, preferably, the control mechanism 25 further includes a safety device 26 which can selectively, depending on the active function of the display system 1, block at least one of the control elements 8B, 8C, 8D in order to prevent any incorrect user command which could possibly lead to damage to parts.

[0048] As already explained above, in the example illustrated in figures 4 to 7 The second cam 35 (heart-shaped) is mounted in the third level of the chronograph seconds wheel 27. Furthermore, the hammer 43 is driven by the chronograph function control organ 8C (located at four o'clock on the timepiece 2). In other words, when the user activates the chronograph function control organ 8C (located at four o'clock on the timepiece 2), the force exerted by the user is used to move the hammer 43 to contact the peripheral surface of the second cam 35.

[0049] The second cam 35 is arranged so that, when the hammer 43 strikes the peripheral surface of the second cam 35, the driven wheel 27B is moved to a predetermined angular position so that the single indicator 5C displays the starting value of the chronograph seconds function. Typically, by pressing the control organ 8C located at four o'clock, the control mechanism 25 is arranged to activate the chronograph function. More precisely, the movement of the chronograph function control organ 8C (located at four o'clock on the timepiece 2) by the user causes the hammer 43 to strike the peripheral surface of the second cam 35 to initialize the chronograph function value via the indicator 5C (for example, the seconds indicator 5C is moved to twelve o'clock).

[0050] Next, thanks to the elastic return when the user releases the chronograph control organ 8C (located at four o'clock on the timepiece 2), the control mechanism 25 is arranged so that the locking device 29 is activated; that is, the locking stop 37A is pressed against the driven wheel 27B to prevent any movement of the driven wheel 27B. In other words, when the user releases the chronograph control organ 8C, the initial value of the chronograph indicator 5C is maintained (for example, the seconds indicator 5C is moved to twelve o'clock).

[0051] In the active chronograph function position (i.e., outside the current time function), the chronograph function start / stop control organ 8D (located at two o'clock on the timepiece 2) can be operated by a user to measure time on demand (counting mode), i.e., to move the single seconds indicator 5C. The control mechanism 25 is arranged, in particular by its column-mounted pivot 25A, so that, upon the first actuation of the chronograph function start / stop control organ 8D, the clutch lever 39 of the clutch device 31 is in the engaged position and the locking lever 37 of the locking device 29 is in the unlocked position.It is therefore understood that, during the first actuation of the 8D organ for starting / ending the chronograph function counting, the double pinion 41 meshes with the driving wheels 22 and 27B driven to couple the movement of the driven wheel 27B to that of the driving wheel 22 so that the single seconds indicator 5C displays a chronograph function seconds count by the movement of the driving wheel 22.

[0052] In the chronograph function's measuring position, the chronograph function start / stop control organ 8D (located at two o'clock on the timepiece 2) can be actuated by a user to stop the chronograph function's time measurement on demand, i.e., to stop the single seconds indicator 5C at a particular position chosen by the user. The control mechanism 25 is arranged, in particular by its column-mounted pivot 25A, so that, upon the second actuation of the chronograph function start / stop control organ 8D, the clutch lever 39 of the clutch device 31 is in the disengaged position and the locking lever 37 of the locking device 29 is in the locked position.It is therefore understood that, during the second actuation of the 8D start / end control organ of the chronograph function, the upper pinion 41A of the double pinion 41 moves away from the driven wheel 27B and the locking stop 37A pivots against the driven wheel 27B in order to prevent any movement of the driven wheel 27B so that the single seconds indicator 5C displays a stationary value of the chronograph function seconds selected by the user.

[0053] The chronograph function is therefore in stop mode again. It can then be understood that the chronograph function can switch back to counting mode to resume timekeeping via the seconds indicator 5C by pressing the chronograph start / stop control 8D (located at two o'clock on timepiece 2). Alternatively, the chronograph function can be reset by pressing the chronograph control 8C (located at four o'clock on timepiece 2). The stop mode will be retained, but the single indicator 5C will be reset to its initial position, for example, at twelve o'clock. The chronograph function can be reactivated to resume timekeeping via the seconds indicator 5C by pressing the chronograph start / stop control 8D (located at two o'clock on timepiece 2).

[0054] Finally, in the active chronograph function position (i.e., in both counting and stop modes), the current time function control 8B (located at ten o'clock on the timepiece 2) can be operated by a user to display the current time seconds using the single seconds indicator 5C. The control mechanism 25 is arranged, particularly by its column-mounted pivot 25A, so that, when the current time function control 8B (located at ten o'clock on the timepiece 2) is operated, the lever 39 of the clutch device 31 is in the disengaged position and the rocker 37 of the locking device 29 is in the unlocked position.It is therefore understood that, when the control organ 8B of the current time function is activated (located at ten o'clock on the clock part 2), the upper pinion 41A of the double pinion 41 moves away from the driven wheel 27B and the locking stop 37A moves away from the driven wheel 27B so that, by the first cam 32 - follower 33 of first cam 32 assembly, the driving wheels 22 and driven wheels 27B resynchronize as already explained above, so that the single indicator 5C again displays the value of the seconds of the current time.

[0055] Control mechanism 25 is partially represented by the example of Figures 13 and 14We can see in particular the column-mounted mobile 25A and the levers 46, 47, 48 cooperating respectively with the organ 8B for controlling the current time function (located at ten o'clock on the timepiece 2), the organ 8C for controlling the chronograph function (located at four o'clock on the timepiece 2) and the organ 8D for controlling the start / end of the chronograph function counting (located at two o'clock on the timepiece 2).

[0056] The column-based mobile 25A has several levels and is intended to cooperate with all sub-assemblies 21, 121, 221 as better explained below so that the activation of each of the control organs 8B, 8C, 8D allows the control mechanism 25 to activate the functions and / or modes of the display system 1 for each of the indicators 5A for hours, 5B for minutes and 5C for seconds.

[0057] More specifically, a first level comprises a first toothed section D1 (column wheel) designed to cooperate with the hook 45A of the ring 45 (explained below). A second level (below the first level) comprises a second toothed section D2 (ratchet wheel) designed to cooperate with the hook 48A of the lever 48 (which cooperates with the start / stop control element 8D for the chronograph function). Finally, a third level (below the second level) comprises a third toothed section D3 (column wheel) designed to cooperate with the hook 37B of the rocker 37 of the locking device 29 and the feeler 39A of the lever 39 of the clutch device 31.

[0058] Thus, when the current time function is activated by pressing the control element 8B located at ten o'clock, the control mechanism 25 is arranged, via the lever 46 and the hook 45A of the ring 45, to move the column-mounted mobile 25A in order, on the one hand, to force the disengaged position of the clutch device 31 (upper pinion 41A disengaged) and, on the other hand, by the movement of a lever 38A - finger 38 assembly, to maintain, by contact of the finger 38 against the lever 37C, the non-immobilizing position of the locking device 29 (locking stop 37A disengaged) so that the single indicator 5C displays the value of the seconds of the current hour, that is to say, copies the angle of rotation of the seconds wheel of the finishing gear 9 in the example illustrated in figures 4 to 7 .

[0059] Furthermore, when the chronograph function is activated by pressing the chronograph function control organ 8C located at four o'clock on the timepiece 2, the control mechanism 25 is arranged, via the lever 47, to move the hammer 43 and thus initialize the value of the chronograph function by the indicator 5C (for example the seconds indicator 5C is moved to twelve o'clock) and then impose the immobilization position of the immobilization device 29 (immobilization stop 37A against the driven wheel 27B) so that the initial value of the indicator 5C for the chronograph function is maintained.

[0060] Finally, when the chronograph function is active and the counting mode is activated by pressing the chronograph function start / stop control organ 8D located at two o'clock on the timepiece 2, the control mechanism 25 is arranged, via the lever 48, to move the column-mounted mobile 25A to force the clutch device 31 into the engaged position (coupling of the driving wheel 22 and the driven wheel 27B by the double pinion 41) and the locking device 29 into the disengaged position (locking stop 37A out of the way) so that the single seconds indicator 5C displays a chronograph function seconds count by moving the driving wheel 22 (the seconds wheel of the finishing gear train 9 in the example illustrated in figures 4 to 7 ).

[0061] Next, when the chronograph function stop mode is activated by pressing the chronograph function start / stop control organ 8D located at two o'clock on the timepiece 2 a second time in succession, the control mechanism 25 is arranged, via the lever 48, to move the column-mounted mobile 25A to impose the disengaged position of the clutch device 31 (double pinion 41 moved apart) and the immobilizing position of the immobilizing device 29 (immobilizing stop 37A against the driven wheel 27B) so that the single seconds indicator 5C displays a stationary chronograph function seconds count value.

[0062] As explained above, when the display of the measured time on demand (chronograph function) is no longer useful to the user, the latter presses the control organ 8B located at ten o'clock so that the single indicator 5C displays the value of the seconds of the current hour, that is to say, copies the rotation angle of the seconds wheel of the finishing gear 9 in the example illustrated in figures 4 to 7 It is then understood that the value of the seconds of the chronograph function can no longer be displayed again and that pressing the 8C control organ of the chronograph function located at four o'clock resets the 5C seconds indicator (for example at twelve o'clock) to be ready for a new measurement of time on demand (chronograph function).

[0063] Preferably, the control mechanism 25 includes a safety device 26 which can selectively, depending on the active function and / or mode of the display system 1, block at least one of the control organs 8B, 8C, 8D in order to prevent any incorrect user command which could possibly lead to damage to parts.

[0064] Of course, the safety device 26 is applicable to any system 1 displaying chronograph and current time functions, that is to say in particular not necessarily applying to a single indicator between the two functions and being able to apply to a more elaborate chronograph function (in particular with more than two control elements).

[0065] The safety device 26 mainly comprises the ring 45, which pivots relative to a fixed point of the watch movement 3. More specifically, in the example illustrated in Figures 13 and 14, the ring 45 has recesses 45B, 45C, stop 45D and rocker (not visible) intended to selectively prevent, according to the operation of the display system 1, the depressing of one of the control elements 8B, 8C, 8D.

[0066] According to a first operating logic of the control mechanism 25, the safety device 26 is arranged to prevent the simultaneous pressing of the current time control organ 8B (located at ten o'clock on the timepiece 2) and the chronograph control organ 8C (located at four o'clock on the timepiece 2). To this end, the safety device 26 comprises a first recess 45B intended to cooperate with the pin 46A of the lever 46 and a second recess 45C intended to cooperate with the pin 47A of the lever 47.

[0067] As seen at the figure 14When the chronograph function control organ 8C (located at four o'clock on the timepiece 2) is pressed in, the pin 47A is inserted into the second recess 45C. The shape of the second recess 45C then imposes an angular position of the ring 45 in which it is no longer possible for the pin 46A to be inserted into the first recess 45B (the pin 46A hits against the slope of the first recess 45B and the current time function control organ 8B can no longer be activated as long as the chronograph function control organ 8C is pressed in).

[0068] Conversely, as seen in the figure 13When the current time function control organ 8B (located at ten o'clock on the timepiece 2) is pressed in, the pin 46A is inserted into the first recess 45B. The shape of the first recess 45B then imposes an angular position of the ring 45 in which it is no longer possible for the pin 47A to be inserted into the second recess 45C (the pin 47A hits against the slope of the second recess 45C and the chronograph function control organ 8C can no longer be activated as long as the current time function control organ 8B is pressed in).

[0069] According to a second operating logic of the control mechanism 25, the safety device 26 is arranged to prevent the start / stop control organ 8D of the chronograph function (located at two o'clock on the timepiece 2) from being pressed when the display system 1 is in current time mode. To this end, the safety device 26 includes a stop 45D designed to cooperate with a stop 48B provided on the lever 48.

[0070] As seen at the figure 13 When display system 1 is in current time mode, the angular position of ring 45 causes stop 45D to be located on the path of lever 48B, preventing lever 48 from pivoting (chronograph function start / stop control 8D can no longer be activated until chronograph function control 8C has been pressed as illustrated in the figure 14Conversely, when lever 48 is at least partially depressed (the 8D control organ for starting / ending the chronograph function countdown is activated), the stop 48B of lever 48 is in the path of the stop 45D which no longer allows the lever 46 to be activated (the 8B control organ for the current time function becomes inoperative).

[0071] According to a third operating logic of the control mechanism 25, the safety device 26 is arranged to prevent the chronograph function control organ 8C from being pressed when the display system 1 is in chronograph counting mode. To this end, the safety device 26 includes a rocker (not visible) designed to cooperate with the lever 47 directly or indirectly, such as with the hammer 43.Thus, when the display system 1 is in chronograph function counting mode, the angular position of the rocker (not visible) induces a location of the rocker (not visible) intended to be on the path of lever 47 directly or indirectly such as on the path of hammer 43, in which it is no longer possible for lever 47 to rock (the organ 8C controlling the chronograph function (which notably causes the reset) can no longer be activated until the organ 8D controlling the start / end of the chronograph function counting has been pressed again to be at the end of the counting).

[0072] In the example illustrated in figures 8 to 10 The second subset 121 of the display system 1 is presented. The second subset 121 concerns the alternative display of minutes for the current time function or the chronograph function using the same indicator 5B (a central hand in the example of the figure 1The second subassembly 121 mainly comprises a phase-shift tracking mechanism 123, a locking device 129, and a control mechanism 25 to allow on-demand switching between the current time function and the chronograph function (and between the two modes, i.e., start and stop, of the chronograph function). The second subassembly 121 of the display system 1 is intended to be coupled to a driving wheel 122 of the watch movement 3, enabling the counting of minutes for the current time function. In the example illustrated in figures 8 to 10 , the driving wheel 122 is connected to the timing wheel of the finishing gear 9 of the watch movement 3.

[0073] The phase-shift tracking mechanism 123 mainly comprises a minute chronograph wheel 127 and a differential device 131. Preferably, the single minute indicator 5B is fixed to the minute chronograph wheel 127 (hand driven onto one end of a pivoting hollow shaft 127A of the wheel 127 in the example of the figure 9 , in which tree 27A is received).

[0074] The minute chronograph mechanism 127 comprises a driven wheel 127B to which the hollow shaft 127A is fixed. The driven wheel 127B is coupled by friction (for example, a friction spring) to the driving wheel 122. Finally, a first cam 127D is fixed to the driven wheel 127B and is intended to cooperate with a first hammer 133, as will be explained below.

[0075] Advantageously, this configuration allows, without any other constraints, the driven wheel 127B to be synchronized with the rotation of the driving wheel 122. Thus, when the current time function is activated by pressing the control element 8B located at ten o'clock, the driven wheel 127B is synchronized with the driving wheel 122 so that the single indicator 5B displays the value of the minutes of the current hour, that is to say, it copies the angle of rotation of the minute wheel of the finishing gear 9 in the example illustrated in figures 8 to 10 .

[0076] The immobilizing device 129 mainly comprises a jaw 137 equipped with two stops 137A, 137B for immobilizing the driven wheel 127B. The stops 137A, 137B are mounted on either side of the driven wheel 127B to form the jaw 137. The immobilizing device 129 is arranged to move the jaw 137 between an immobilizing position to prevent any movement of the driven wheel 127B, and a position of no immobilization in which the driven wheel 127B is free from any constraint of the immobilizing device 129.Typically, as will be better explained below, when the current time function is activated by pressing the control organ 8B located at ten o'clock, the immobilizing device 129 is arranged to impose the non-immobilizing position for the jaw 137 so that the single indicator 5B displays the value of the minutes of the current hour, i.e. copies the rotation angle of the timer wheel of the finishing gear 9 in the example illustrated in the. figures 8 to 10 .

[0077] Furthermore, the locking device 129 is arranged so that, in the locked position, the jaw 137 closes until the two locking stops 137A and 137B are against the driven wheel 127B, thus preventing any movement of the driven wheel 127B. Typically, as will be explained in more detail below, when the chronograph function is activated by pressing the control organ 8C located at four o'clock, the jaw 137 in the locked position allows the single minute indicator 5B to display a fixed value for the chronograph minutes.

[0078] In the example illustrated in Figures 9 and 10 The immobilizing device 129 comprises two plates 129A, 129B coupled at one end by a pinion 129C and, at the other end, by an elastic element 129D (a coil spring in the example of Figures 9 and 10). It is understood that the two plates 129A, 129B are arranged to perform opposite translations, one above the other, and each has teeth to permanently mesh with the pinion 129C. In the example of the Figures 9 and 10 To actuate the jaw 137, only the first plate 129A (which includes the first stop 137A) is actuated. This plate, via the pinion 129C, drives the reverse translation of the second plate 129B (which includes the second stop 137B). This configuration allows for a complex movement (two-point clamping / loosening) using a simple translational movement of the first plate 129A. Furthermore, the guidance is very precise, and the thickness (along the Z-axis) remains very compact.

[0079] Preferably, the elastic element 129D is arranged to impose the immobilization position of the jaw 137. In other words, when the jaw 137 is to be moved into the position of no immobilization, the force of the element 129D must be countered and when the control of the first plate 129A is released, the elastic element 129D, by elastic return, allows the reverse movement of the jaw 137 into the immobilization position.

[0080] It is understood that, in the immobilized position of the jaw 137, the driving wheels 122 and 127B driven wheels will be able to move relative to each other. However, advantageously, the relative movement of the driving wheel 122 with respect to the driven wheel 127B is stored by the differential device 131. In other words, the differential device 131 allows the phase shift between the driving wheels 122 and 127B driven wheels without desynchronization.

[0081] Typically, when the current time function is activated by pressing the control element 8B located at ten o'clock, the locking device 129 is arranged to move the jaw 137 to its unlocked position so that, via the differential device 131, the driving wheels 122 and 127B synchronize as already explained above, so that the single indicator 5B displays the value of the minutes of the current hour, i.e., copies the rotation angle of the timer wheel of the finishing gear 9 in the example illustrated in figures 8 to 10 .

[0082] Of course, the immobilizing device 129 is applicable to other functions for selectively achieving immobilization in a chronograph mechanism, particularly a chronograph that does not necessarily have a single indicator between two functions and that can be applied to a time value other than minutes. The immobilizing device 129 could also perform the function of a selective vertical clutch between two wheels by using stops 137A, 137B that move one of the wheels axially between first and second positions, either directly or indirectly.

[0083] The differential device 131 is designed to selectively allow the driven wheel 127B to be driven in rotation in conjunction with the driving wheel 122 so that the single minute indicator 5B displays a chronograph minute count based on the movement of the driving wheel 122. The differential device 131 primarily comprises first wheels 131A and second wheels 131B and an epicyclic gear train 135. The differential device 131 is arranged to advantageously retain any relative displacement of the driving wheel 122 with respect to the driven wheel 127B.In other words, the differential device 131 quantifies the phase shift between the driving wheel 122 and the driven wheel 127B, i.e., it moves by the differential rotation angle between the driving wheel 122 and the driven wheel 127B, and is able to reproduce this phase shift when switching from the chronograph function to the current time function to display the value of the minutes of the current time function by the single minute indicator 5B.

[0084] In the example illustrated in figures 8 to 10 The epicyclic gear train 135 is mounted by friction between the first 131A and second 131B wheels. As best seen in the example of the figure 8A planetary shaft 135A serves as a pivoting element for the first 131A and second 131B wheels; that is, these wheels are mounted to rotate freely around the planetary shaft 135A. Furthermore, a planet carrier 135B is mounted to rotate rigidly with the planetary shaft 135A and supports at least two planets 135C. Each planet 135C meshes, at its upper end, with a first peripheral ring 135D and, at its lower end, with a second peripheral ring 135E.

[0085] In the example illustrated in the figure 8The serrated outer diameter (friction pads) of the first peripheral ring 135D is mounted against the smooth inner diameter of the first wheel 131A. Similarly, the serrated outer diameter (friction pads) of the second peripheral ring 135E is mounted against the smooth inner diameter of the second wheel 131B. Furthermore, the driven wheel 127B is coupled to the outer teeth of the first wheel 131A, and the driving wheel 122 is coupled to the outer teeth of the second wheel 131B. Finally, a second cam 131C is fixed (or as a single unit in the example of the figure 8) on the planetary shaft 135A of the differential device 131 and intended to cooperate with a second hammer 143 as will be explained below to pass between an active memorization position of the differential device 131 (second hammer 143 away from the second cam 131C) and an inactive position (second hammer 143 against the second cam 131C) of the differential device 131.

[0086] Thus, when the current time function is activated by pressing the control element 8B located at ten o'clock, the phase-shift tracking mechanism 123 is arranged to impose the non-immobilizing position of the jaw 137 and an inactive position of the differential device 131 so that the single indicator 5B displays the value of the minutes of the current hour, i.e., copies the rotation angle of the timer wheel of the finishing gear 9 in the example illustrated in figures 8 to 10 .

[0087] Furthermore, when the chronograph function is activated by pressing the control organ 8C located at four o'clock, the phase-shift tracking mechanism 123 is arranged to enforce the locking position of the jaw 137 and the active memorization position of the differential device 131 so that the single minute indicator 5B displays a fixed starting position for the chronograph function's minute count. It is therefore understood that any relative displacement of the driving wheel 122 with respect to the driven wheel 127B (locked by the locking device 129) is registered by the differential device 131 by moving, via the epicyclic gear train 135 (second wheel 131B, satellites 135C, satellite carrier 135B, planetary shaft 135A), the second cam 131C.Therefore, at any time from the activation of the chronograph function, i.e. before, during and after the chronograph counting, any phase shift of the leading wheel 122 relative to the wheel 127B is memorized by the dedicated movement of the second cam 131C.

[0088] Next, when the chronograph function is activated by pressing the control element 8D at two o'clock for the first time, the phase-shift tracking mechanism 123 is arranged to enforce the non-immobilizing position of the jaw 137 and to maintain the active memorization position of the differential device 131. The single minute indicator 5B then displays (trailing display) a chronograph function minute count by the movement of the driving wheel 122 via friction with the driven wheel 127B (which therefore maintains its potential phase shift, i.e., the differential angle relative to the driving wheel 122, between the activation of the chronograph function by pressing the control element 8C at four o'clock and the start of the chronograph function count activated by pressing the control element 8D at two o'clock for the first time).

[0089] Finally, when the chronograph function's stop function is activated by pressing the control organ 8D at two o'clock a second time, the phase-tracking mechanism 123 is arranged to re-engage the locking position of the jaw 137 and to maintain the active memorization position of the differential device 131 so that the single minute indicator 5B displays a fixed position of the chronograph function's minute count. Consequently, any phase shift of the driving wheel 122 relative to the wheel 127B is always checked and memorized by the dedicated movement of the second cam 131C.

[0090] The control mechanism 25 of the display system 1 allows, in particular, the control of sub-assemblies such as the functions of the second sub-assembly 121 of the minutes. The control mechanism 25 mainly comprises a first assembly first hammer 133 - first cam 127D of the minutes, a second assembly second hammer 143 - second cam 131C of the minutes, a column-mounted mobile 25A, the organ 8B for controlling the current time function (located at ten o'clock on the timepiece 2), the organ 8C for controlling the chronograph function (located at four o'clock on the timepiece 2) and the organ 8D for controlling the start / end of the chronograph function counting (located at two o'clock on the timepiece 2).

[0091] As explained above, preferably, the control mechanism 25 includes a safety device 26 which can selectively, depending on the active function of the display system 1, block at least one of the control components 8B, 8C, 8D in order to prevent any incorrect user command which could possibly lead to damage to parts.

[0092] In the example illustrated in figures 8 to 10The first cam 127D (heart-shaped) is mounted to rotate with the driven wheel 127B. Furthermore, the first hammer 133 (mounted on the first plate 134A) is driven (specifically by lever 47) by the chronograph function control 8C (located at four o'clock on the timepiece 2). In other words, when the user activates the chronograph function control 8C (located at four o'clock on the timepiece 2), the force exerted by the user is used to move the first hammer 133 to contact the peripheral surface of the first cam 127D.

[0093] The first cam 127D is arranged so that, when the first hammer 133 strikes the peripheral surface of the first cam 127D, the driven wheel 127B is moved to a predetermined angular position so that the single indicator 5B displays the starting minute value of the chronograph function. Typically, by pressing the control organ 8C located at four o'clock, the control mechanism 25 is arranged to activate the chronograph function. More precisely, the movement of the chronograph function control organ 8C (located at four o'clock on the timepiece 2) by the user causes the first hammer 133 to strike the peripheral surface of the first cam 127D to initialize the chronograph function value via the indicator 5B (for example, the minute indicator 5B is moved to twelve o'clock).

[0094] Furthermore, the second cam 131C (heart-shaped) is mounted to rotate directly onto the planetary shaft 135A. In addition, the second hammer 143 (mounted on the second plate 134B) is driven by the movement (specifically by the control lever 45E) of the chronograph function control organ 8C (located at four o'clock on the timepiece 2). In other words, when the user activates the chronograph function control organ 8C (located at four o'clock on the timepiece 2), the force exerted by the user is used (via the ring 45) to move the second hammer 143 away from the peripheral surface of the second cam 131C.

[0095] It is therefore understood that any relative displacement of the driving wheel 122 with respect to the driven wheel 127B (blocked by the locking device 129) is recorded by the differential device 131 by moving, via the epicyclic gear train 135 (second wheel 131B, satellites 135C, satellite carrier 135B, planetary shaft 135A), the second cam 131C. Consequently, at any time from the activation of the chronograph function, i.e., before and after the chronograph countdown, any phase shift of the driving wheel 122 with respect to the wheel 127B is recorded by the dedicated displacement of the second cam 131C.

[0096] Next, thanks to the elastic return when the user releases the chronograph control organ 8C (located at four o'clock on the timepiece 2), the control mechanism 25 is arranged so that the locking device 129 is activated; that is, the locking stops 137A and 137B are pressed against the driven wheel 127B to prevent any movement of the driven wheel 127B. In other words, when the user releases the chronograph control organ 8C, the initial value of the chronograph indicator 5B is maintained (for example, the seconds indicator 5B is moved to twelve o'clock).

[0097] In the active chronograph function position (i.e., outside the current time function), the chronograph function start / stop control organ 8D (located at two o'clock on the timepiece 2) can be operated by a user to measure time on demand (counting mode), i.e., to move the single minute indicator 5B. The control mechanism 25 is arranged so that, upon the first actuation of the chronograph function start / stop control organ 8D, the jaw 137 of the locking device 129 is in the unlocked position and to maintain the active memorization position of the differential device 131.It is therefore understood that, during the first actuation of the 8D organ for starting / ending the chronograph function count, the unique 5B minute indicator then displays (trailing display) a count of the chronograph function minutes by the movement of the driving wheel 122 via friction with the driven wheel 127B (which keeps in memory the phase shift, i.e. the differential angle of the driving wheel 122 relative to the driven wheel 127B for the entire duration that the chronograph function is active).

[0098] In the chronograph function's measuring position, the chronograph function start / stop control organ 8D (located at two o'clock on the timepiece 2) can be actuated by a user to stop the chronograph function's time measurement on demand, i.e., to stop the single minute indicator 5B at a particular position chosen by the user. The control mechanism 25 is arranged so that, upon the second actuation of the chronograph function start / stop control organ 8D, the jaw 137 of the locking device 129 is in the locking position and to maintain the active memorization position of the differential device 131.It is therefore understood that, during the second actuation of the 8D organ for starting / ending the chronograph function count, any movement of the driven wheel 127B is prevented so that the unique 5B minute indicator displays a stationary value for the minutes of the chronograph function chosen by the user while checking and memorizing any phase shift of the driving wheel 122 relative to the driven wheel 127B.

[0099] The chronograph function is therefore once again in stop mode. It can then be understood that the chronograph function can switch back to counting mode to resume timekeeping via the minute indicator 5B by again activating the chronograph start / stop control 8D (located at two o'clock on the timepiece 2). Alternatively, the chronograph function can be reset by pressing the chronograph control 8C (located at four o'clock on the timepiece 2). The stop mode will be retained, but the single indicator 5B will be repositioned to its initial value, for example, at twelve o'clock, and the new phase shift of the driving wheel 122 relative to the driven wheel 127B will be memorized by the differential device 131.The chronograph function counting mode can be activated to start time counting by the minute indicator 5B by again actuating the chronograph function start / end counting control organ 8D (located at two o'clock on the timepiece 2).

[0100] Finally, in the active chronograph function position (i.e., in both counting and stop modes), the current time function control 8B (located at ten o'clock on the timepiece 2) can be operated by a user to display the current hour's minutes using the single minute indicator 5B. The control mechanism 25 is arranged so that, when the current time function control 8B (located at ten o'clock on the timepiece 2) is operated, the jaw 137 of the locking device 129 is in the unlocked position and the differential device 131 is in the inactive position.

[0101] It is therefore understood that, when the current time function control mechanism 8B (located at ten o'clock on the timepiece 2) is activated, the second hammer 143 strikes against the peripheral surface of the second cam 131C so that the latter resets its position by driving the driven wheel 127B (planetary shaft 135A, planet carrier 135B, planets 135C, first wheel 131A), particularly because the driving wheel 122 is substantially stationary and, incidentally, so is the second wheel 131B. In other words, the phase shift stored by the differential device 131 is applied to the driven wheel 127B so that the driving and driven wheels 122 and 127B resynchronize, allowing the single indicator 5B to again display the minutes of the current hour.It is then understood that the value of the minutes of the chronograph function can no longer be displayed again and that pressing the 8C control organ of the chronograph function located at four o'clock resets the 5B minute indicator (for example to twelve o'clock) to be ready for a new measurement of time on demand (chronograph function).

[0102] Preferably, as seen in the example of Figures 15 and 16 The second sub-assembly 121 for minutes includes a safety device 151 arranged to compensate for gear backlash, particularly when the display system 1 switches from the chronograph function to the current time function. The safety device 151 notably limits or even eliminates any display inaccuracy of the single minute indicator 5B when the current time function is activated.

[0103] Of course, the safety device 151 is applicable to any display system 1 with an indicator 5A, 5B, 5C equipped with at least one differential device 131 (and / or 231 below), that is to say in particular not necessarily including a chronograph function, not necessarily applying to a single indicator between two functions and being able to apply to a different time value than minutes.

[0104] Indeed, it has been observed that the differential itself and the transmissions between the driving wheel 122 and the driven wheel 127B exhibit gear backlash that can slightly shift (by a few degrees) the display of the single minute indicator 5B. In particular, the torques passing through the second sub-assembly 121 during the return to current time mode are those that can potentially generate the most significant backlash when the phase shift stored by the differential device 131 is applied to the driven wheel 127B.

[0105] The safety device 151 mainly comprises a constraint mechanism 153 and a control device 156. More specifically, in the example illustrated in Figures 15 and 16 , the safety device 151 is intended to be mounted between the lever 46 (associated with the organ 8B for controlling the current time function) and the minute chronograph mobile 127.

[0106] Thus, the safety device 151 is arranged to be activated by the current time function control element 8B (located at ten o'clock on the timepiece 2). The control device 156 is arranged to drive the constraint wheel 153 when the current time function control element 8B is activated. The control device 156 comprises a constraint rocker 155 and a control slide 157 arranged to orient a constraint finger 157A along a looped path B, during which the constraint finger 157A contacts the constraint wheel 153 to rotate it through a predefined angle, such as, for example, between 5 and 30 degrees, such as 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, or 30 degrees. The looped path B (dotted line) is formed by a cam 155B provided on the rocker 155 against which the finger 157A is guided.

[0107] As explained above, the lever 46, via in particular the ring 45, actuates the plate 134B but also the control drawer 157. More precisely, the control drawer 157 is arranged to impart a translation A (direction of the arrow of the Figures 15 and 16 ) or -A (opposite direction of the arrow Figures 15 and 16 ) of back-and-forth control when the current time function control element 8B is activated. Thus, the pivoting movement of lever 46 causes a translational movement A of the control slide 157. This translation A pushes the constraint finger 157A of the control slide 157 against the lower part of the cam 155B of the constraint rocker 155. The constraint finger 157A is elastically cantilevered by means of an elastic arm extending parallel to the direction of translation A. The rocker 155 is arranged to pivot elastically (elastic element 155A, for example, a coil spring in the example of the Figures 15 and 16) relative to a fixed point of the watch movement 3 in particular thanks to the shape of the cam 155B.

[0108] Therefore, at the end of translation A, the constraint finger 157A has traveled approximately half the path B (dotted line) and has passed over the cam 155B by elastic return. Thus, upon elastic return of the current time function control element 8B, the lever 46 imposes a translation -A on the control slide 157. By this translation -A, the constraint finger 157A completes the path B (dotted line) and comes into contact with the second ratchet wheel 153B of the constraint wheel 153 in order to apply a rotational constraint to it.

[0109] The second ratchet wheel 153B is coupled by friction (for example, a friction spring) to a first tension wheel 153A, which is permanently meshed with the driven wheel 127B. Thus, the rotational force exerted by the first wheel 153A eliminates all backlash in the second subassembly 121. The safety device 151 is configured so that the rotational force exerted by the first wheel 153A is greater than the force required to eliminate the backlash in the second subassembly 121. In other words, once the backlash is eliminated, the safety device 151 is configured so that the remaining generated force is discharged by the friction of the second ratchet wheel 153B (which pivots relative to the first tension wheel 153A with the remaining generated force).

[0110] It is therefore understood that, when the current time function is activated (the control element 8B located at ten o'clock), the safety device 151 exerts, via the first wheel 153B, a force that puts all the gears of the second sub-assembly 121 under stress (or tension). This limits or even eliminates any gear backlash, particularly when the phase shift stored by the differential device 131 is applied to the driven wheel 127B. The safety device 151 thus limits or even eliminates any inaccuracy in the display of the single minute indicator 5B when the current time function is activated.

[0111] In the example illustrated in Figures 11 and 12The third subassembly 221 of the display system 1 is presented. The third subassembly 221 functions similarly to the second subassembly 121 and concerns the alternative display of the times for the current time function or the chronograph function using the same indicator 5A (a central hand in the example of the figure 1 The third subassembly 221 mainly comprises a phase-shift tracking mechanism 223, a first locking device 229, and the control mechanism 25 to allow switching on demand between the current time function and the chronograph function (and between the two modes, i.e., start and stop, of the chronograph function). The third subassembly 221 of the display system 1 is intended to be coupled to a driving wheel 222 for counting the hours of the current time function. In the example illustrated in Figures 11 to 12The driving wheel 222 (complete rotation in one hour) is coupled by the linkage 222A to the driving wheel 122 (complete rotation in one minute) via a dedicated wheel of the differential device 131 of the second subassembly 121 to simplify the display mechanism 1, as illustrated by the example of figures 8 to 12 include the hours and minutes (indicators 5A and 5B).

[0112] The phase-shift tracking mechanism 223 mainly comprises a chronograph hour wheel 227, a second locking device 249, and a differential device 231. In the example illustrated in Figures 11 and 12 The unique 5A hour indicator is fixed to a display wheel 228 (hand driven onto one end of a hollow shaft 228A pivoting from the display wheel 228 in the example of the figure 11 , in which the hollow 27A shaft and 127A shaft are concentrically received).

[0113] The chronograph hour wheel 227 comprises a first driven wheel 227B meshed with the display wheel 228. The first driven wheel 227B is rotationally fixed to a second intermediate wheel 227C. Thus, the first driven wheel 227B is coupled to the driving wheel 222 by the differential device 231 (more precisely, by the second wheel 231B of the differential device 231) and the second intermediate wheel 227C. Finally, a first cam 227D is fixed between the first driven wheel 227B and the second intermediate wheel 227C, and is intended to cooperate with a first hammer 233 as will be explained below.

[0114] Advantageously, this configuration allows, without any other constraints, the driven wheel 227B to be synchronized with the rotation of the driving wheel 222. Thus, when the current time function is activated by pressing the control element 8B located at ten o'clock, the first driven wheel 227B is synchronized with the driving wheel 222 so that the single indicator 5A displays the current hour value, that is, it copies the rotation angle of the hour wheel of the finishing gear 9 in the example illustrated in Figures 11 and 12 .

[0115] The first immobilizing device 229 mainly comprises a first rocker 237 equipped with a stop 237A for immobilizing the first driven wheel 227B and, incidentally, the display wheel 228. The first immobilizing device 229 is arranged to move the rocker 237 between a immobilized position to prevent any movement of the first driven wheel 227B and, incidentally, the display wheel 228, and a position of no immobilization in which the first driven wheel 227B and, incidentally, the display wheel 228, is free from any constraint of the first immobilizing device 229.

[0116] The second locking device 249 mainly comprises a second rocker 257 equipped with a stop 257A for locking the locking wheel 231D. The second locking device 249 is arranged to move the rocker 257 between a locking position to prevent any movement of the locking wheel 231D and, consequently, of the second cam 231C, and a position of no locking in which the locking wheel 231D and, consequently, of the second cam 231C, are free from any constraint of the second locking device 249.

[0117] The differential device 231 is designed to selectively allow the first driven wheel 227B to be driven in rotation in conjunction with the driving wheel 222 so that the single hour indicator 5A displays a chronograph function countdown by the movement of the driving wheel 222. Similar to the minute differential device 131, the hour differential device 231 primarily comprises first 231A and second 231B wheels and an epicyclic gear train. The differential device 231 is arranged to advantageously retain any relative displacement of the driving wheel 222 with respect to the first driven wheel 227B and, incidentally, of the display wheel 228.In other words, the differential device 231 quantifies the phase shift between the driving wheels 222 and the driven wheel 227B, i.e. moves by the differential rotation angle between the driving wheels 222 and 227B, and is able to reproduce this phase shift when switching from the chronograph function to the current time function to display the value of the hours of the current time function by the single hour indicator 5A.

[0118] In the example illustrated in Figures 11 and 12The epicyclic hour train is not visible but is similar in configuration to the minute train (135), meaning that it is mounted by friction between the first 231A and second 231B wheels. A planetary shaft serves as a pivoting element for the first 231A and second 231B wheels, allowing them to rotate freely around the planetary shaft. Furthermore, a planet carrier is mounted to rotate directly with the planetary shaft and supports at least two planets. Each planet meshes, at its upper end, with a first peripheral ring gear and, at its lower end, with a second peripheral ring gear.

[0119] Similar to the example of the figure 8The serrated outer diameter (friction pads) of the first peripheral ring gear is mounted against the smooth inner diameter of the first wheel 231A. Similarly, the serrated outer diameter (friction pads) of the second peripheral ring gear is mounted against the smooth inner diameter of the second wheel 231B. Furthermore, the second intermediate wheel 227C is coupled to the outer teeth of the first wheel 231A. Finally, a second cam 231C is fixed to the planetary shaft of the differential device 231 and is designed to cooperate with a second hammer 243, as explained below, to switch between an active memorization position of the differential device 231 (second hammer 243 away from the second cam 231C) and an inactive position (second hammer 243 against the second cam 231C) of the differential device 231.

[0120] Thus, when the current time function is activated by pressing the control element 8B located at ten o'clock, the phase-shift tracking mechanism 223 is arranged to impose the non-locking position of the first stop 237A and an inactive position of the differential device 231 so that the single indicator 5A displays the current hour value, i.e., copies the rotation angle of the hour wheel of the finishing gear 9 in the example illustrated in Figures 11 and 12 .

[0121] Furthermore, when the chronograph function is activated by pressing the control element 8C located at four o'clock, the phase-shift tracking mechanism 223 is arranged to enforce the locking position of the first locking stop 237A, the non-locking position of the second locking stop 257A, and the active memorization position of the differential device 231 so that the single hour indicator 5A displays a fixed starting position for the chronograph function's hour counting (e.g., at twelve o'clock). It is therefore understood that any relative displacement of the driving wheel 222 with respect to the first driven wheel 227B (blocked by the locking device 229) is registered by the differential device 231 by moving, via the epicyclic gear train (second wheel 231B, satellites, satellite carrier, planetary shaft), the second cam 231C.

[0122] Then, when the start of the chronograph function counting is activated by pressing the control organ 8D located at two o'clock for the first time, the phase-shift tracking mechanism 223 is arranged to impose the non-immobilization position of the first immobilization stop 237A, the immobilization position of the second immobilization stop 257A and to maintain the active memorization position of the differential device 231.The unique 5A hour indicator then displays (trailing display) a count of the hours of the chronograph function by the movement of the driving wheel 222 via the differential device 131 (second wheel 231B, satellites, first wheel 231A) and the first driven wheel 227B and incidentally of the display wheel 228, while keeping the phase shift, i.e. the differential angle of the driving wheel 222, between the activation of the chronograph function by pressing the control organ 8C located at four o'clock and the start of the counting of the activated chronograph function by pressing the control organ 8D located at two o'clock for the first time.

[0123] Finally, when the chronograph function's stop is activated by pressing the control element 8D at two o'clock a second time, the phase-tracking mechanism 223 is arranged to re-engage the first stop 237A in its immobilized position, the second stop 257A in its un-immobilized position (specifically, via the teeth D1 of the column-mounted wheel 25A cooperating with the hook 257B of the second rocker 257), and to maintain the active memorization position of the differential device 131 so that the single hour indicator 5A displays a fixed position of the chronograph function's hour count. Consequently, any phase shift of the driving wheel 222 relative to the first driven wheel 227B, and consequently of the display wheel 228, is always checked and memorized by the dedicated movement of the second cam 231C.

[0124] The control mechanism 25 of the display system 1 allows, in particular, the control of sub-assemblies such as the functions of the third sub-assembly 221 of the hours. The control mechanism 25 mainly comprises a first assembly first hammer 233 - first cam 227D of the hours, a second assembly second hammer 243 - second cam 231C of the minutes, a column-mounted mobile 25A, the control organ 8B of the current hour function (located at ten o'clock on the timepiece 2), the control organ 8C of the chronograph function (located at four o'clock on the timepiece 2) and the control organ 8D of the start / end of the chronograph function counting (located at two o'clock on the timepiece 2).

[0125] As explained above, preferably, the control mechanism 25 includes a safety device 26 which can selectively, depending on the active function of the display system 1, block at least one of the control components 8B, 8C, 8D in order to prevent any incorrect user command which could possibly lead to damage to parts.

[0126] In the example illustrated in Figures 11 and 12The first cam 227D (heart-shaped) is mounted to rotate with the first driven wheel 227B. Furthermore, the first hammer 233 (mounted on the first plate 134A) is driven (specifically by lever 47) by the chronograph function control organ 8C (located at four o'clock on the timepiece 2). In other words, when the user activates the chronograph function control organ 8C (located at four o'clock on the timepiece 2), the force exerted by the user is used to move the first hammer 233 to contact the peripheral surface of the first cam 227D.

[0127] The first cam 227D is arranged so that, when the first hammer 233 strikes the peripheral surface of the first cam 227D, the first driven wheel 227B, and incidentally the display wheel 228, is moved to a predetermined angular position so that the single indicator 5A displays the starting hour value of the chronograph function. Typically, by pressing the control organ 8C located at four o'clock, the control mechanism 25 is arranged to activate the chronograph function. More precisely, the movement of the chronograph function control organ 8C (located at four o'clock on the timepiece 2) by the user causes the first hammer 233 to strike the peripheral surface of the first cam 227D to initialize the chronograph function value via the indicator 5A (for example, the hour indicator 5A is moved to twelve o'clock).

[0128] Furthermore, the second cam 231C (heart-shaped) is mounted to rotate directly onto the planetary shaft. In addition, the second hammer 243 (mounted on the second plate 134B) is driven by the movement (specifically by the control lever 45E) of the chronograph function control organ 8C (located at four o'clock on the timepiece 2). In other words, when the user activates the chronograph function control organ 8C (located at four o'clock on the timepiece 2), the force exerted by the user is used (via the ring 45) to move the second hammer 243 away from the peripheral surface of the second cam 231C.

[0129] It is therefore understood that any relative movement of the driving wheel 222 with respect to the first driven wheel 227B (blocked by the immobilizing device 129), and incidentally of the display wheel 228, is recorded by the differential device 231 by moving, via the epicyclic train (second wheel 231B, satellites, satellite carrier, planetary shaft), the second cam 231C.

[0130] Next, thanks to the elastic return upon release of the chronograph control organ 8C (located at four o'clock on the timepiece 2) by the user, the control mechanism 25 is arranged so that the locking device 229 is activated, i.e., the first locking stop 237A is pressed against the second intermediate wheel 227C to prevent any movement of the first driven wheel 227B and, consequently, of the display wheel 228. At the same time, the control mechanism 25 is arranged so that the locking device 249 is deactivated, i.e., the second locking stop 257A is moved away from the locking wheel 231D to allow any movement of the planetary shaft and, consequently, of the second cam 231C.In other words, when the user releases the chronograph function control organ 8C, the initial value of the chronograph function indicator 5A is maintained (for example, the seconds indicator 5A is moved to twelve o'clock) and the phase shift relative to the driving wheel 222 is checked and memorized.

[0131] In the active position of the chronograph function (i.e., outside of the current time function), the 8D chronograph function start / stop counting control organ (located at two o'clock on the timepiece 2) can be operated by a user to measure a time on demand (counting mode), i.e., move the single 5A hour indicator. The control mechanism 25 is arranged so that, at the first actuation of the start / end control organ 8D of the chronograph function, the first immobilization stop 237A of the immobilization device 229 is in the position of no immobilization, the second immobilization stop 257A is in the immobilization position (in particular by the teeth D1 of the column-mounted mobile 25A cooperating with the hook 257B of the second rocker 257) and to maintain the active memorization position of the differential device 231 (second hammer 243 away from the second cam 231C).It is therefore understood that, at the first actuation of the 8D organ for starting / ending the chronograph function's counting, the unique hour indicator 5A then displays (trailing display) a counting of the hours of the chronograph function by the movement of the driving wheel 222 via the differential device 231 (second wheel 231B, satellites, first wheel 231A, intermediate second wheel 227C) of the first driven wheel 227B and incidentally of the display wheel 228, while keeping in memory the phase shift, i.e. the differential angle of the driving wheel 222 relative to the first driven wheel 227B for the entire duration that the chronograph function is active.

[0132] In chronograph function measurement position, the 8D chronograph function start / stop counting control organ (located at two o'clock on timepiece 2) can be operated by a user to stop the chronograph function time measurement on demand, i.e., stop the unique 5A hour indicator at a particular position chosen by the user.The control mechanism 25 is arranged so that, during the second actuation of the start / end control organ 8D of the chronograph function, the first immobilization stop 237A of the immobilization device 229 is in the immobilization position, the second immobilization stop 257A is in the non-immobilization position (in particular by the teeth D1 of the column-mounted mobile 25A cooperating with the hook 257B of the second rocker 257) and to maintain the active memorization position of the differential device 231 (second hammer 243 away from the second cam 231C).It is therefore understood that, during the second actuation of the 8D organ for starting / ending the chronograph function's counting, any movement of the first driven wheel 227B and incidentally of the display wheel 228, is prevented so that the single hour indicator 5A displays a fixed value for the chronograph function's hour count chosen by the user while checking and memorizing any phase shift of the driving wheel 222 relative to the first driven wheel 227B and incidentally of the display wheel 228.

[0133] The chronograph function is therefore in stop mode again. It can then be understood that the chronograph function can switch back to counting mode to resume timekeeping via the hour indicator 5A by pressing the chronograph start / stop control 8D (located at two o'clock on timepiece 2). Alternatively, the chronograph function can be reset by pressing the chronograph control 8C (located at four o'clock on timepiece 2). The stop mode will be retained, but the single indicator 5C will be reset to its initial position, for example, at twelve o'clock. The chronograph function can be reactivated to resume timekeeping via the hour indicator 5A by pressing the chronograph start / stop control 8D (located at two o'clock on timepiece 2).

[0134] Finally, in the active chronograph function position (i.e., in both counting and stop modes), the current time function control 8B (located at ten o'clock on the timepiece 2) can be operated by a user to display the current hour value using the single hour indicator 5A. The control mechanism 25 is arranged so that, when the current time function control 8B (located at ten o'clock on the timepiece 2) is operated, the first stop 237A of the locking device 229 is in the unlocked position and the differential device 231 is in the inactive position.

[0135] It is therefore understood that, when the control organ 8B of the current time function is activated (located at ten o'clock on the clock part 2), the force exerted by the user is used to strike the second hammer 243 against the peripheral surface of the second cam 231C so that the latter resets its position by driving the first driven wheel 227B and incidentally the display wheel 228 (planetary shaft, satellite carrier, satellites, first wheel 231A, second intermediate wheel 227C), in particular because the driving wheel 222 is substantially immobile and incidentally also the second wheel 231B. In other words, the phase shift memorized by the differential device 231 is applied to the first driven wheel 227B and incidentally to the display wheel 228, so that the driving wheels 222 and driven wheels 227B resynchronize so that the single indicator 5A again displays the value of the current hour.It is then understood that the chronograph function's hour value can no longer be displayed again and that pressing the chronograph function control organ 8C located at four o'clock resets the hour indicator 5A (for example to twelve o'clock) to be ready for a new time measurement on demand (chronograph function).

[0136] The invention is not limited to the embodiments and variations shown, and other embodiments and variations will be obvious to those skilled in the art. Thus, the above embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features of different embodiments can also be combined and / or interchanged to provide other embodiments.Without limitation, it may be envisaged to decouple functionalities on several different components, such as, for example, decoupling the first cam 227D from the wheel 228 which carries the unique 5A hour indicator as explained above and applying it to the first cam 127D to mount it offset from the wheel 127B which carries the unique 5B minute indicator.

[0137] In another example illustrated in Figures 17 and 18 , a variant embodiment of the first subset 21 of the display system 1 is presented. References for elements identical to the example of figures 4 to 7are retained. It can be observed that the chronograph wheel 27 now only comprises the first cam 32 - follower 33 assembly of the first cam 32, and that the driven wheel 27B and the second cam 35 have been decoupled without departing from the scope of the invention. Thus, a return wheel 28 is used to transmit the movements to the driven wheel 27B. This configuration advantageously allows the locking device 29 to be relocated further away from the chronograph wheel 27, which advantageously allows for an off-center display of the seconds. However, the operation explained for the example of the figures 4 to 7 remains completely unchanged.

[0138] Furthermore, the control finger 38 can be concentric with the column-mounted mobile 25A, which allows for a more compact display mechanism 1. However, the operation explained for the example of the figures 4 to 7remains completely identical. Only the shape of the lever 37C of the rocker 37 is adapted to the location of the control finger 38.

[0139] Conversely, components can be grouped according to the intended embodiment, such as the number of indicators 5A, 5B, 5C. Thus, in the example explained above, hammers 143 and 243 may or may not be formed on the same control plate 134B. Similarly, hammers 133 and 233 may or may not be formed on the same control plate 134A. By way of non-limiting example, the figure 19This presents an example of a variant of the second and third subassemblies of the display system in which the locking devices 129 and 229 are coupled. More specifically, the rocker 237 equipped with the locking stop 237A is fixedly mounted on the first plate 129A. In fact, when the locking devices 129 and 229 are actuated, the driven wheel 127B and the second intermediate wheel 227C are locked in place by means of the same plates 129A, 129B, which makes the display mechanism 1 more compact.

[0140] In the examples cited above, where indicators 5A and 5B are used, the second and third subassemblies 121 and 221 are linked by the gear train 222A (comprising the driving wheel 222) so that only a single driving wheel 122 is connected to the finishing gear train 9. According to another embodiment, two separate driving wheels 122 and 222 could be connected to the same finishing gear train 9. Thus, the idler gear train 222A could be removed, particularly if only the minutes (indicator 5B) are desired, i.e., without the hours (indicator 5A), without departing from the scope of the invention.

[0141] Of course, other types of displays / indicators than those described above may be provided such as a cylinder, a sphere, a strip, a ring, one or more needles respectively pointers or one or more discs in linear, continuous, discontinuous, intermittent or retrograde operating mode with semi-instantaneous or instantaneous jump and / or in combination with these types of display listed without going out of the scope of the invention. LIST OF REFERENCES

[0142] 1 - Display system 2 - Clockwork component 3 - Clock movement 3A - Mainplate 4 - Oscillator 5A - Hour indicator 5B - Minute indicator 5C - Seconds indicator 8A - Crown 8B - Current time function control 8C - Chronograph function control 8D - Start / stop counting control 9 - Finishing wheel 21 - First seconds subset 22 - Driving wheel 23 - Selective coupling mechanism 25 - Control mechanism 25A - Column wheel 26 - Safety device 27 - Seconds chronograph wheel 27A - Shaft 27B - Driven wheel 28 - Return wheel 29 - Locking device 31 - Clutch device 32 - First cam 33 - First cam follower 33A - Lever 33B - elastic element 34 - friction spring 35 - second cam 37 - rocker arm 37A - locking stop 37B - hook 37C - control lever 38 - control finger 38A - control lever 39 - lever 39A - feeler 41 - double pinion 41A - upper pinion 41B - pinionlower 43 - hammer 45 - ring 45A - hook 45B - first recess 45C - second recess 45D - stop 45E - control lever 46 - lever 46A - peg 47 - lever 47A - peg 48 - lever 48A - hook 48B - stop 121 - second minute sub-assembly 122 - driving wheel 123 - phase-shift tracking mechanism 127 - minute chronograph wheel 127A - hollow shaft 127B - driven wheel 127D - first cam 129 - locking device 129A - first plate 129B - second plate 129C - pinion 129D - elastic element 131 - differential device 131A - first wheel 131B -second wheel 131C -second cam 133 -first hammer 134A -first hammer plate 134B -second hammer plate 135 -epicyclic gear train 135A -planetary shaft 135B -planet carrier 135C -planets 135D -first peripheral ring gear 135E -second peripheral ring gear 137 -jaw 137A -first locking stop 137B -second locking stop 143 -second hammer 151 -safety device 153-Constraint wheel 153A -First wheel 153B -Second ratchet wheel 155 -Constraint rocker 155A -Elastic element 155B -Cam 156 -Control device 157 -Control drawer 157A -Constraint finger 221 -Third hour sub-assembly 222 -Drive wheel 222A -Reverse wheel 223 -Phase tracking mechanism 227 -Hour chronograph wheel 227B -First driven wheel 227C -Second intermediate wheel 227D -First cam 229 -First locking device 228 -Display wheel 228A -Hollow shaft 231 -Differential device 231A -First wheel 231B -Second wheel 231C -Second cam 231D -Locking flywheel 233 - first hammer 237 - rocker 237A - locking stop 243 - second hammer 249 - second locking device 257 - second rocker 257A - second locking stop 257B - hook A - translational movement B - path D1 - first tooth D2 - second tooth D3 - third tooth

Claims

1. Display system (1) for a mechanical timepiece (2) comprising a mechanical clock movement (3) arranged to count time, a function called current time, allowing at least one time value to be displayed using an indicator (5A, 5B), characterized in that the display system (1) comprises at least one subassembly (121, 221) coupled to the watch movement (3) and comprising a control mechanism (25) for selectively measuring a duration, a function known as the chronograph, allowing the same time value to be alternately displayed using a single indicator (5A, 5B) for each of the current time and chronograph functions and in thatsaid at least one subassembly (121, 221) includes a phase-tracking mechanism (123, 223) arranged to mechanically monitor the angular offset between a driving wheel (122, 222) of the watch movement (3) and a driven wheel (127B, 227B) of said at least one subassembly (121, 221) enabling the driven wheel (127B, 227B), which controls the movement of the single indicator (5A, 5B), to be moved, when switching from the chronograph function to the current time function, according to said angular offset so that the single indicator (5A, 5B) displays the current time function.

2. Display system (1) according to the preceding claim, wherein the phase-shift tracking mechanism (123, 223) includes a differential device (131, 231) mounted between the driving wheel (122, 222) and the driven wheel (127B, 227B) and arranged to memorize any angular offset between the driving wheel (122, 222) and the driven wheel (127B, 227B) when the chronograph function is active.

3. Display system (1) according to the preceding claim, wherein the differential device (131, 231) comprises an epicyclic gear train (135) mounted between a first (131A) wheel and a second (131B) wheel, the first (131A) wheel being connected to the driven wheel (127B, 227B) and the second (131B) wheel being connected to the driving wheel (122, 222), the epicyclic gear train (135) being arranged to memorize the differential rotation angle between the driving wheel (122, 222) and the driven wheel (127B, 227B) when the chronograph function is active and to restore this phase shift when switching from the chronograph function to the current time function so that the single indicator (5A, 5B) displays the current time function.

4. Display system (1) according to claim 2 or 3, wherein the differential device (131, 231) is controlled by a cam (131C, 231C) - hammer (143, 243) assembly controlled by the control mechanism (25) and arranged to restore the angular offset stored to the wheel (127B, 227B) driven when the hammer (143, 243) strikes the cam (131C, 231C) so that the single indicator (5A, 5B) displays the current time function.

5. Display system (1) according to any one of the preceding claims, wherein said at least one subassembly (121, 221) comprises a device (129, 229) for immobilizing the driven wheel (127B, 227B) controlled by the control mechanism (25) so that the single indicator (5A, 5B) displays a fixed counting position of the chronograph function.

6. Display system (1) according to the preceding claim, wherein the immobilizing device (129, 229) comprises at least one immobilizing stop (137A, 137B, 237A) arranged to move between an immobilizing position to prevent any movement of the driven wheel (127B, 227B) and a position of no immobilization in which the driven wheel (127B, 227B) is free from any constraint of the immobilizing device (129, 229).

7. Display system (1) according to any one of the preceding claims, wherein the driven wheel (127B, 227B) is controlled by a cam (127D, 227D) - hammer (133, 233) assembly controlled by the control mechanism (25) and arranged to move the driven wheel (127B, 227B) to a predefined angular position when the hammer (133, 233) strikes the cam (127D, 227D) so that the single indicator (5A, 5B) displays a starting count value of the chronograph function.

8. Display system (1) according to any one of the preceding claims, wherein said at least one time value is the hour or minute.

9. Timepiece (2) characterized in that it includes the display system (1) according to any one of the preceding claims.

10. Timepiece (2) according to the preceding claim, comprising a first sub-assembly (121) in which the time value is the minute and a second sub-assembly (221) in which the time value is the hour.

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