Chronograph mechanism

Abstract

The invention relates to a chronograph mechanism comprising - the stopwatch hour hand (6) and the stopwatch minute hand (7) in an overlaid position with the normal hour hand (3) and the normal minute hand (4) to display a normal time, - the stopwatch hour hand (6), the stopwatch minute hand (7) and the second hand (8) are driven to be positioned at 12 o'clock, before the time measurement, - the stopwatch hour hand (6), the stopwatch minute hand (7) and the second hand (8) are driven to measure the time, - the stopwatch hour hand (6), the stopwatch minute hand (7) and the second hand (8) are blocked to display the measured time, and - the stopwatch hour hand (6) and the stopwatch minute hand (7) are repositioned in an overlaid position with the normal hour hand (3) and the normal minute hand (4) after displaying the measured time in order to display the normal time. Fig. 3a

Description

Chronograph mechanism TECHNICAL FIELD OF THE INVENTION The present invention relates to a chronograph mechanism. The invention also relates to a watch comprising a chronograph mechanism. STATE OF THE ART Mechanical watches, and in particular complicated watches, are constructed in such a way as to be able to display several indications such as the date, month, week, power reserve, chronograph, time difference, etc. In the case of a chronograph watch, reading the displayed information is often difficult due to the dial's clutter and reduced legibility caused by the various apertures and indications, the centered hour, minute, and second hands, as well as the small subdials with their off-center, non-coaxial hands. To improve visibility, watches exist where the normal time hands and chronograph hands are superimposed. For example, document EP 1491972 describes a watch mechanism that includes i) a minute hand and an hour hand for displaying normal time, and ii) a split-seconds minute hand and a split-seconds hour hand arranged coaxially with the normal time display hands. In normal mode, the normal time hands and the split-seconds hands move synchronously and are superimposed.To display a desired time, the split-seconds hands are locked in a stop mode to mark a desired instant and re-engaged, after a desired time interval has elapsed, in a synchronous movement with the normal time hands in a position superimposed on them, then return to zero. The mechanism described in document EP1491972 is designed to temporarily decouple two gear trains, one for normal timekeeping and the other for chronograph timekeeping, which are normally synchronized. The mechanism described in document EP1491972 is described as an alternative to a conventional chronograph (see paragraph

[0088] Indeed, it allows you to pause to display a moment or duration but does not include a chronograph seconds hand, and does not provide a way to reset the hands. SUBJECT OF THE INVENTION One aim of the present invention is to propose a chronograph mechanism that minimizes the size of the dial compared to existing mechanisms. Another object of the present invention is to provide a chronograph mechanism in which the chronograph components are at least partly invisible or masked when the chronograph mechanism is inactive, for example the chronograph hands. These objects are at least partially affected by the present invention. To this end, a first aspect of the present invention relates to a chronograph mechanism, capable of driving and blocking a chronograph hour hand, a chronograph minute hand and a sweep second hand, arranged coaxially with a normal hour hand and a normal minute hand. The chronograph mechanism or mechanism for measuring time according to the present invention comprises a chronograph hour hand, a chronograph minute hand and a second hand, arranged coaxially with a normal hour hand and a normal minute hand. The mechanism controls the movement of the hands; in other words, it drives or blocks them, in the following way: - The chronograph hour hand and the chronograph minute hand are driven synchronously and in a superimposed position, respectively with the normal hour hand and with the normal minute hand, to display normal time. - The chronograph hour hand, the chronograph minute hand, and the second hand are driven to be positioned at 12 o'clock, before the time measurement. - The chronograph hour hand, the chronograph minute hand, and the second hand are driven to measure time. - the chronograph hour hand, the chronograph minute hand and the second hand (8) are locked to display the measured time, and - the chrono hour hand and the chrono minute hand are repositioned in a superimposed position and re-engaged synchronously, respectively with the normal hour hand and with the normal minute hand, after displaying the measured time to display the normal time. The chronograph hand(s) are defined as chronograph hands, also called counter hands or split-seconds hands. The normal hands are defined as normal time hands. These normal or normal time hands display normal time, in other words, the normal operation of the mechanism. Advantageously, when the mechanism is running normally, the chronograph hands (hours and minutes) are superimposed. The chronograph hands move from this superimposed position during time measurement when the mechanism is in chronograph mode. After the measured time has been displayed, the chronograph minute and hour hands are then repositioned superimposed with the normal minute and hour hands, respectively. In other words, the space occupied is equivalent to three hands, while the mechanism has five. This superimposition minimizes the bulk of the mechanism, particularly on a dial designed to be coupled with it. This makes it easier to read the normal time, as the user is not visually distracted by the chronograph hands. The user can read the normal time using three normal hands (hour, minute, and second), just as on a watch without a chronograph. Advantageously, according to the present invention, the chronograph is read directly on the dial, that is, without additional subdials. The absence of subdials avoids visual clutter. This provides better visibility of both the chronograph and normal time hands. Advantageously, according to the present invention, the chronograph function of the mechanism is concealed when the mechanism is in normal operation, particularly because the chronograph minute and hour hands are superimposed on the normal minute and hour hands. In other words, the chronograph according to the present invention allows the display elements of the chronograph function to be visible only when the latter is in use. This simplifies the dial and eliminates the need for superfluous hands, such as the chronograph minute and hour hands, when they are not in use. Preferably, in a superimposed position, either the chronograph hour hand is below the regular hour hand, and the chronograph minute hand is below the regular minute hand, or the chronograph hour hand is above the regular hour hand, and the chronograph minute hand is above the regular minute hand. Thus, the chronograph and regular hour hands on the one hand, and the chronograph and regular minute hands on the other, occupy the space of a single hand in normal operation. Visually, The user cannot distinguish the chronograph hands from the normal hands, which makes it easier to read the normal time. Preferably, the seconds hand serves as both the regular seconds hand and the chronograph seconds hand. This dual function of the seconds hand reduces the number of hands in the mechanism required to perform both functions: normal timekeeping and chronograph. Preferably, the seconds hand continues its sweep after the measured time has been displayed. Thus, after the measured time has been read, when exiting the chronograph function, the seconds hand is released from the reading position and continues its sweep to display the normal seconds. Preferably, the mechanism is operated by a single pusher. - The chronograph hour hand, the chronograph minute hand, and the seconds hand can be moved to the 12 o'clock position following an initial press of the pusher. - The chronograph hour hand, the chronograph minute hand, and the second hand can be driven to measure time by releasing the pusher. - The chronograph hour hand, the chronograph minute hand, and the second hand can be locked to display the measured time following a second press of the pusher. - The chronograph hour hand and the chronograph minute hand can be moved to a superimposed position, respectively with the normal hour hand and with the normal minute hand, following a third actuation of the pusher. The pusher is an example of an actuator that is operated by the user to control the mechanism, notably to switch between the chronograph function and normal running. Ideally, the pusher is the sole actuator controlling the mechanism. This centralizes control and makes the mechanism easier for the user to operate. Traditional chronograph mechanisms typically use two pushers to control the chronograph function: one to start and stop the chronograph, and another to reset it. Using a single pusher or actuator allows the chronograph function to be concealed or made less visible. This also minimizes the size of the mechanism, particularly within the case that houses it. Preferably, the second hand continues its journey from its position of timing following the said third actuation of the pusher. Preferably, the mechanism includes a split-seconds module (64), equipped with a chronograph hour wheel (66) and a chronograph minute wheel (67), each wheel (66, 67) comprising a chronograph hour (38) and minute (39) core, a clutch and brake board for the hours (52) and minutes (53), a split-seconds wheel for the hours (68) and minutes (71), which are free on the axis of rotation of the chronograph hour wheel (66) and respectively on the axis of rotation of the chronograph minute wheel (67), and an intermediate chronograph hour (69) and chronograph minute (72) wheel. The split-seconds module (or system) allows the chronograph hour hand to be superimposed on the normal hour hand, and the chronograph minute hand on the normal minute hand. In the present invention, the split-seconds module allows the normal hour and minute hands to be superimposed on the chronograph hour and minute hands. This superimposition of hands replaces the resetting of the hands generally found in prior art chronograph mechanisms. The use of the split-seconds module in the chronograph mechanism allows the chronograph hour and minute hands to be hidden when the mechanism is running normally. Preferably, the split-seconds wheel for hours and minutes and the intermediate wheel for chronograph hours and minutes each include conjugate drive means such that the split-seconds wheel for hours and minutes drives the intermediate wheel for chronograph hours and minutes respectively, so as to superimpose the chronograph hour hand and the chronograph minute hand respectively with the normal hour hand and with the normal minute hand to display normal time. Preferably, the mechanism includes a hammer-actuating module equipped with a hammer. The hammer is capable of striking an hour chronograph heart, a minute chronograph heart, and a second chronograph heart, so as to position the hour chronograph hand, the minute chronograph hand, and the seconds hand at 12 o'clock. When the hammer strikes a heart, it positions the chronograph hand attached to that heart at 12 o'clock. Preferably, the hammer-actuating module is coupled to the pusher or actuator. Pressing the pusher triggers the hammer to strike the hour chronograph heart, the minute chronograph heart, and the second chronograph heart. Preferably, the hammer comprises one angular portion per heart, each angular portion being arranged to bear against a heart, at least one of said angular portions comprising a flexible distal part. The angular portion is also called the flat. Preferably, the hammer is arranged so that each angular portion comes to rest on the corresponding heart simultaneously or almost simultaneously. Preferably, at least one angular portion includes a flexible distal section. The presence of a flexible section on at least one angular portion facilitates simultaneous contact between each angular portion and its corresponding heart. The angular portion containing the flexible distal section has a greater contact stroke on a heart than an angular portion without a flexible distal section. The flexible distal section is deformable when bearing on the heart. This compensates for any play that may exist during contact between the angular portions of the hammer without flexible sections and the hearts. Preferably, the mechanism includes a clutch-disengagement module for the chronograph hour hand and the chronograph minute hand, equipped with an hour clutch rocker and a minute clutch rocker which respectively control a chronograph hour oscillating pinion and a chronograph minute oscillating pinion capable of engaging with respectively an hour clutch and braking board and with a minute clutch and braking board, so as to measure time. The clutch-disengagement module enables the timekeeping function. When the clutch module is disengaged: the chronograph function is inactive, and the minute and hour clutch levers are in the disengaged position so that the chronograph hour and minute oscillating pinions spin freely; in other words, these pinions do not drive the hour and minute clutch and braking boards respectively, and thus the chronograph minute and hour hands do not measure time. When the clutch module is disengaged, the chronograph hour and minute hands are synchronized and superimposed with the normal hour and minute hands. Preferably, when the clutch module is disengaged, the chronograph hour and minute hands are driven by the split-seconds module. When the clutch module is engaged: the chronograph function is active, and the minute and hour clutch levers are in the engaged position so that the chronograph hour and chronograph minute oscillating pinions drive the hour clutch and brake board and the minute clutch and brake board respectively, and thus the chronograph minute and chronograph hour hands measure a time. Preferably, when the clutch module is engaged: the split-seconds hour module is decoupled and the chronograph hour hand is driven by the clutch and brake hour board; for example, the clutch and brake hour board drives the intermediate chronograph hour wheel in contact with the chronograph hour wheel attached to the chronograph hour hand to measure time; the split-seconds minute module is decoupled and the chronograph minute hand is driven by the clutch and brake minute board; for example, the clutch and brake minute board drives the intermediate chronograph minute wheel in contact with the chronograph minute wheel attached to the chronograph minute hand to measure time. The clutch-disengagement module in the engaged position allows time to be measured while maintaining normal operation to display the time. Preferably, in the engaged position, the energy of the watch movement transmitted by a finishing gear powers two kinematic chains, one chain for normal time and a second kinematic chain for the chronograph function. Preferably, in the engaged position, with regard to both normal and chronograph minutes, the finishing gear, for example the intermediate wheel, drives: the split-seconds minute wheel, which meshes with the minute wheel to drive the normal minute hand and thus display the normal time (i.e., the normal time kinematic chain); and, for example, via a deflection connected to the intermediate wheel, the minute clutch and brake board via the minute oscillating pinion. This board is integral with the intermediate chronograph minute wheel. The intermediate chronograph minute wheel meshes with the chronograph minute wheel to... drive the chronograph minute hand and measure time (i.e. chronograph kinematic chain); Preferably, in the engaged position, with regard to normal hours and chronograph hours, the finishing gear, for example the large average mobile, drives: the split-seconds hour wheel in contact with the hour wheel to drive the normal hour hand and thus display the normal time (i.e. normal time kinematic chain), and for example via a deviation connected to the large average mobile, the clutch and braking board of the hours via the oscillating pinion of the hours, said board is integral with the intermediate chronograph hour wheel, the intermediate chronograph hour wheel meshes with the chronograph hour wheel to drive the chronograph hour hand and measure the time (i.e. chronograph kinematic chain); Preferably, the mechanism includes a locking module comprising an hour lock (56) for locking an hour clutch and brake board (52), and a minute lock (57) for locking a minute clutch and brake board (53), so as to display the measured time. The locking module allows the hour counter and minute counter to be locked with the measured hours and minutes to display the measured time. Preferably, the mechanism includes a clutch / disengagement module for the seconds hand. This clutch / disengagement module may be equipped with two articulated clips capable of engaging and disengaging a seconds clutch disc. When the seconds clutch disc is disengaged, the seconds hand stops, allowing the measured time to be displayed alongside the measured seconds. Preferably, the mechanism includes a hammer actuation module, the clutch-disengagement module for the chronograph hour hand and the chronograph minute hand, the clutch-disengagement module for the seconds hand and the locking module for the chronograph hour hand and the chronograph minute hand, can preferably be actuated by a column wheel, the column wheel being driven in rotation by a control, the control being moved by the pusher. Preferably, the clutch-disengagement module of the second hand is actuated by a lever moved by a hammer, said hammer being actuated by the hammer actuation module. According to a second aspect, the invention relates to a watch movement comprising a mechanism according to the invention. Preferably, the movement includes a finishing gear driven by a power source, and in which the mechanism includes a clutch module according to the invention, the finishing gear being engaged with the oscillating hour pinion and the oscillating minute pinion which respectively drive the hour clutch and brake board and the minute clutch and brake board to actuate respectively the chronograph hour hand and the chronograph minute hand so as to measure time. According to a third aspect, the invention relates to a timepiece comprising a movement according to the invention or a mechanism according to the invention. Preferably, the timepiece is a watch equipped with a dial on which are mounted the normal hour hand, the normal minute hand and the second hand, the chrono hour hand, the chrono minute hand. The invention according to the present invention may comprise one embodiment or several embodiments in combination. The embodiments described for the mechanism according to the present invention also apply to the movement and the timepiece according to the invention, mutatis mutandis and vice versa. BRIEF DESCRIPTION OF THE FIGURES Other advantages and features will become apparent from the description of the invention, as well as from the accompanying figures which represent a non-limiting example of the invention, and in which: Figure 1 is a side view of the watch showing the superposition of the watch hands for the chronograph mechanism according to the invention; Figures 2a to 2d successively represent the different display stages of the chronograph watch; Figures 3a to 3e represent the different operating stages of the chronograph mechanism; Figures 4a to 4d represent the different operating stages of a hammer actuation module; Figures 5a and 5b represent the different operating stages of a clutch module for the chronograph hour and minute hands, associated with a disengagement module for the seconds hand; Figures 6a and 6b represent the different stages of operation of the clutch-disengagement module of the seconds hand; Figures 7a and 7b represent the different stages of operation of a module for locking the chronograph hour and minute hands; Figure 8 is a partial isometric view of the split-seconds module, from the back of the watch; Figure 9 is a partial isometric view of the split-seconds module from the dial side of the watch; and Figure 10 is a partial cross-sectional view of the split-seconds module. DESCRIPTION OF EXAMPLES OF THE INVENTION'S IMPLEMENTATION The present description is not exhaustive; each feature can advantageously be combined with any other feature of the same or another embodiment. It should be noted from the outset that the figures are not to scale. One embodiment is illustrated in Figures 1 to 10, but the invention is not limited to this embodiment. In the embodiment illustrated in figures 1 and 2a-2d, the watch 1 comprises a clock movement not shown, a dial 2 and five hands 3, 4, 6, 7 and 8. The five hands 3, 4, 6, 7 and 8 are coaxial and rotate in different planes with respect to the central axis A by being driven by the clock movement. The chronograph watch 1 thus comprises a standard hour hand 3 in the center, a standard minute hand 4 in the center, a chronograph hand or 12-hour counter or chronograph hour hand 6 in the center, a chronograph hand or 60-minute counter or chronograph minute hand 7 in the center, and a standard seconds hand or sweep second hand 8 in the center. The sweep second hand 8 also serves as the chronograph seconds hand. The five hands 3, 4, 6, 7, and 8 of the watch 1 are superimposed on one another (see Fig. 1). The normal hour hand 3 is positioned first near the dial 2. The chronograph hour hand 6 is positioned on top of the normal hour hand 3. The normal minute hand 4 is positioned on top of the chronograph hour hand 6. The chronograph minute hand 7 is positioned on top of the normal minute hand 4. The seconds hand is positioned on top of the chronograph minute hand 7. In normal operation, that is, in normal running mode when the chronograph is inactive (see Fig. 2a), only the chronograph hour hand 6, the hand The minute hand (7) and the seconds hand (8) are visible, so the chronograph watch 1 has a three-hand display. The hour chronograph hand (6) is superimposed on and rotates in sync with the regular hour hand (3). The regular hour hand (3) is thus hidden beneath the hour chronograph hand (6). The minute chronograph hand (7) is superimposed on and rotates in sync with the regular minute hand (4). The regular minute hand (4) is thus hidden beneath the minute chronograph hand (7). The user can read the regular time; in the case of Fig. 2a, the chronograph watch 1 displays 7 hours, 8 minutes, and 13 seconds. The chronograph watch 1 comprises a single operating button or pusher 9. The pusher 9 is three-stage and activates a chronograph mechanism 11 in the illustrated example of the chronograph watch 1 according to the present invention. Following the first press of pusher 9 by the user (Arrow P1 in Fig. 2b), the chronograph mechanism 11 will move to the start position and reset to zero. The seconds hand 8, as well as the chronograph hour hand 6 and split-seconds minute hand 7, will be positioned at 12 o'clock (see Fig. 2b). The timing of the event can then begin. The single seconds hand 8 transforms into the chronograph seconds hand when the chronograph starts. Following the release of the pusher 9 by the user, the chronograph hour hand 6, the chronograph minute hand 7 and the seconds hand 8 are driven by the mechanism 11 to measure time. Following a second press of the pusher 9 by the user (Arrow P2 in Fig. 2c), the chronograph mechanism 11 is moved to the stop position. The user can then read the elapsed time, in the case of Fig. 2c, which is 1 hour, 29 minutes, and 9 seconds. Following a third press of pusher 9 (Arrow P3 in Fig. 2d), the chronograph mechanism 11 returns to its standard operating position (see Fig. 2d). Unlike a traditional chronograph in which the hands are reset, the third press of the chronograph function resets the chronograph hour hand 6 and the chronograph minute hand 7. The chronograph hour hand 6 and the chronograph minute hand 7 reposition themselves over their respective hands, the normal hour hand 3 and the normal minute hand 4. The seconds hand 8 continues its sweep from its timing position. The user can once again read the time; in the case of Fig. 2d, the chronograph watch 1 displays 8 hours, 38 minutes, and 17 seconds. The operation of the chronograph mechanism 11 will be explained in more detail below with reference to Figs. 3a-3e to 10. The operation comprises three stages, a first start stage, a second stop stage and a third catch-up stage. The first start stage is broken down into three phases: a first start phase with the initial state of the chronograph mechanism 11, a second start phase with the resetting of the chronograph mechanism 11, and a third start phase with the starting of the chronograph mechanism 11. The chronograph mechanism 11 includes a column wheel 12. The column wheel 12 is kept in rotation by means of a jumper 13. As shown in Fig. 3a, following the initial actuation of push button 9 by the user, and during the first phase of the first start step, push button 9 will move linearly and press (Arrow P1) against a lever forming a control 14. Control 14 will pivot, which will move a control hook 16 located at one of its free ends. The control hook 16 will engage with the column wheel 12 and rotate it. After the push button 9 is released, control 14 is returned to its initial position by a control spring 17. Simultaneously with the first actuation of the push button 9, the control 14 will actuate a hammer actuation module 18. The hammer actuation module 18 comprises a cocking arm 19. A second free end, opposite the first free end of the control 14, bears against the cocking arm 19 (see Fig. 4a). By pivoting, the cocking arm 19 will cock a cocking spring 20, which rests against a hammer rocker 21. The hammer rocker 21 is returned by a hammer rocker spring 22. The hammer rocker 21 is held in place by a latch 23, which is returned by a latch spring 24. As shown in Figs. 3b and 4b, following the first actuation P1 of the push button 9 by the user, and during the second start phase of the first start step, the pivoting of the column wheel 12 will also actuate the hammer actuating module 18. To achieve this, the hammer actuating module 18 includes a hammer rocker stop 26, equipped with a hammer rocker stop hook 27 located at one of its free ends, the latter cooperating with the column wheel 12. The hammer rocker stop 26 is returned by a hammer rocker stop spring 28. The hammer rocker stop 26 will then clear the passage for the hammer rocker 21. The hammer rocker 21 will subsequently drive a hammer 29. The column wheel 12 will also actuate a clutch-disengagement module 30 for the hour chronograph hand 6 and the minute chronograph hand 7 (see Figs. 5a- 5c). The clutch-disengagement module 30 includes an hour clutch rocker 31 equipped with a clutch rocker hook 32 located at one of its free ends and engaging the column wheel 12. The hour clutch rocker 31 is returned by an hour clutch rocker spring 33. The hour clutch rocker 31 rests against a minute clutch rocker 34. The minute clutch rocker 34 is returned by a minute clutch rocker spring 36 (visible in Fig. 3a). The hour clutch rocker 31 will be held initially by a clutch rocker hook 37 in order to prevent engaging while the hammer 29 presses on an hour chrono cam or heart 38, a minute chrono cam or heart 39 and a second chrono cam or heart 41. The control 14 continues to press on the winding arm 19, until the winding arm 19, by pivoting, pivots the lock 23 which then releases the hammer rocker 21. Thanks to the winding force of the winding spring 20, the hammer rocker 21 will drive the hammer 29, and the hammer 29 will come to press on the chronograph hearts of the hours 38, minutes 39 and seconds 41 (see Figs. 4b and 5b). The movement of the hammer 29 will have two effects. The first effect is that the eccentric being driven onto it will move a safety hook 42 which cooperates with the clutch rocker hook 37 of the hour clutch rocker 31. The disengagement of the clutch rocker hook 37 from the safety hook 42 releases the hour clutch rocker 31 and the minute clutch rocker 34 at the end of the hammer 29's stroke. The second effect of the hammer's movement is that it also pivots a disengagement lever 43, which in turn drives a seconds hand clutch-disengagement module 44 for the seconds hand 8, comprising two clamps 45 and 46. These two clamps are articulated together, for example, by a knee joint. The clamps 45 and 46 disengage the seconds hand 8 while the hammer 29 presses on the chronograph hearts of the hours 38, minutes 39, and seconds 41 (Figs. 3b, 5b, and 6b). As shown in Fig. 3c, following the first actuation P1 and the release of pusher 9 by the user, and during the third phase of the first start step, the hammer 29 returns to its initial starting position due to the release of pusher 9. The hammer 29 releases the pressure on the clutch lever 43, which thus returns to its starting position. The clutch calipers 45 and 46 also return to their starting position under the action of their spring 47. The second hand 8 then begins to move. The hammer 29 releases the hook 42 via the eccentric whose beak comes to be positioned just behind the clutch rocker hook 37 of the hour clutch rocker 31. The hour clutch rocker 31 is ready to be reattached in the next step. As shown in Fig. 3d, following a second actuation of the push button 9 by the user (Arrow P2), and in the second stop stage, the control 14 will again switch and take the control hook 16, rotating the column wheel 12. By rotating, the column wheel 12 actuates the hammer rocker blocker 26, which prevents the hammer rocker 21 from driving the hammer 29. By rotating, the column wheel 12 actuates the seconds clutch-disengagement module 44 with the two clamps 45 and 46, which lift and disengage a seconds clutch disc 48, and thus stop the seconds hand 8 (see Figs. 6a and 6b). As it rotates, the column wheel 12 actuates the two levers 31 and 34: the hour clutch lever 31, which disengages an oscillating hour pinion 49, and the minute clutch lever 34, which disengages an oscillating minute pinion 51. By disengaging the oscillating hour pinion 49 and the oscillating minute pinion 51, the chronograph hour hand 6 and the chronograph minute hand 7 are respectively disengaged. As they disengage, the two clutch levers 31 and 34 cause the safety catch 42 to flex, which then immediately re-engages with the clutch lever catch 37 of the hour clutch lever 31. When the chronograph is engaged, the oscillating pinion at hours 49 engages with a clutch and brake board at hours 52, and the oscillating pinion at minutes 51 engages with a clutch and brake board at minutes 53. The oscillating pinion at hours 49 and the oscillating pinion at minutes 51 then engage with the appropriate gears of the watch movement, for example via a mobile of the finishing gear, which in turn drives the chronograph hand at hours 6 and the chronograph hand at minutes 7. The clutch and brake board for the 52-hour hand is mounted coaxially with the 38-hour chronograph heart. The clutch and brake board for the 53-minute hand is mounted coaxially with the 39-minute chronograph heart. As it rotates, the column wheel 12 actuates a locking module 54 for the hour chronograph hand 6 and the minute chronograph hand 7. The locking module 54 includes an hour stopper 56 which bears against a minute stopper 57 (see Figs. 7a and 7b). The column wheel 12 actuates the hour stopper 56 by engaging with an hour stopper hook 58 located at one of its ends. free. The hour 56 lock is returned by an hour 59 lock spring and the minute 57 lock is returned by a minute 61 lock spring. The hour stopper 56 and the minute stopper 57 pivot and stop the chronograph hour hand 6 and the chronograph minute hand 7 respectively. To do this, the hour stopper 56 has a protrusion 62 which comes into contact with the clutch and brake board of the hour hand 52. Similarly, the minute stopper 57 has a protrusion 63 which comes into contact with the clutch and brake board of the minute hand 53 (visible in Figs. 7a, 7b and 8). As shown in Fig. 3e, following a third actuation of the push button 9 by the user (Arrow P3), and in the third catch-up step, the control 14 will again switch, which will cause the control hook 16 to rotate the column wheel 12. As it rotates, the column wheel 12 actuates the seconds hand clutch-disengagement module 44 with the two clamps 45 and 46, which release the seconds clutch disc 48 and thus allow the seconds hand 8 to resume its normal operating course. As it rotates, the column wheel 12 actuates the hour stopper 56 and the minute stopper 57, which respectively release the pressure on the hour clutch and brake plate 52 and the minute clutch and brake plate 53, and consequently on the hour chronograph hand 6 and the minute chronograph hand 7 (see Fig. 7a). The locking module 54 for the hour chronograph hand 6 and the minute chronograph hand 7 actuates these two hands 6 and 7 via a split-seconds module 64. The split-seconds module 64 has the following configuration and operation. The locking module 54 includes an hour chronograph wheel 66 and a minute chronograph wheel 67. The hour chronograph movement 66 comprises the hour chronograph heart 38, the hour clutch and brake board 52, a split-seconds hour wheel 68, which is freely adjusted on the axis, and an intermediate hour chronograph wheel 69, these elements being mounted coaxially. The minute chronograph movement 67 comprises the minute chronograph heart 39, the minute clutch and brake board 53, a split-seconds minute wheel 71, which is freely adjusted on the axis, and an intermediate minute chronograph wheel 72, these elements being mounted coaxially. When the pressure on the chronograph hand at 6 o'clock is released, it becomes completely free, allowing the split-seconds wheel at 68 o'clock to engage and catch up with the chronograph wheel at 73 o'clock, thus allowing the chronograph hand at 6 o'clock to overlap with the normal hour hand at 3 o'clock. And when The pressure on the minute 7 chrono hand is released, the latter having become completely free will allow the minute 71 split-seconds wheel to engage and catch up with a minute 74 chrono wheel, thus allowing the minute 7 chrono hand to overlap with the normal minute 4 hand. The intermediate chronograph hour wheel 69 meshes with a chronograph hour wheel 76. The intermediate chronograph minute wheel 72 meshes with a chronograph minute wheel 77. The 68-hour split-seconds wheel is attached to a 78-hour split-seconds heart, and the 71-minute split-seconds wheel is attached to a 79-minute split-seconds heart. A split-seconds hour shoe 81 is mounted with its spring on the intermediate chronograph hour wheel 69, and a split-seconds minute shoe 82 is mounted with its spring on the intermediate chronograph minute wheel 72. In normal operation, the split-seconds heart for the hours and minutes 78 and 79, attached respectively to the split-seconds wheel for the hours and minutes 68 and 71, drives respectively the split-seconds shoe for the hours and minutes 81 and 82, attached respectively to the intermediate chronograph hour and minute wheel 69 and 72. Thus, the normal hour hand 3 and the normal minute hand 4 are respectively perfectly aligned with the chronograph hour hand 6 and the chronograph minute hand 7. When the chronograph pusher 9 is engaged or disengaged, the chronograph mechanism 11 drives the clutch and brake plates of the hour 52 and minute 53 hands. The spring of the split-seconds hand of the hour 81 and minute 82 hands is very weak, and the friction of the split-seconds hand of the hour 81 and minute 82 hands on the split-seconds heart of the hour 78 and minute 79 hands is less than the torque reaching the chronograph hands of the hour 6 and minute 7 hands, the split-seconds hand of the hour 81 and minute 82 hands will slip on the split-seconds heart of the hour 78 and minute 79 hands. The intermediate wheel of the chronograph hours and minutes 69 and 72, attached to the rest of the chronograph movement of the hours 66 and minutes 67, will therefore be able to drive the corresponding chronograph wheel of the hours 76 and minutes 77, while the split-seconds wheel of the hours 68 and minutes 71 will continue to be driven by the associated normal wheel of the hours 73 and minutes 74, the heart 78 rotating the shoe 81 according to its course. Compared to a classic single-button chronograph, the chronograph mechanism 11 according to the invention has the following differences and advantages. The chronograph hands for the hours 66 and minutes 67 are "split-seconds" type. Therefore, they must be connected to both the minute wheel (driven by the finishing wheel) and the chronograph wheel, and each chronograph hand for the hours 66 and minutes 67 must be perfectly free at the moment of the split-seconds operation. In normal operation, the timer gear drives the split-second wheels of the hours 68 and minutes 71 and the oscillating pinions of the hours 49 and minutes 51 (driven for example by a deviation of the timer gear) spin in the air since they are not engaged with the clutch and brake boards of the hours 52 and minutes 51. In chronograph mode, the minute train always drives the split-seconds wheels of the hour 68 and minute 71 to display the normal time, and the chronograph hour 76 and chronograph minute 77 wheels. But the clutch and brake boards of the hour 52 and minute 51 are engaged with the oscillating pinions of the hour 49 and minute 51, and drive the chronograph hour 76 and chronograph minute 77 wheels with a torque greater than that of the minute train: the split-seconds shoe of the hour 81 and minute 82 will slip on the split-seconds heart of the hour 78 and minute 79. During the initial start-up and reset phase, when the chronograph mechanism 11 is triggered, hammer 29 presses the chronograph hearts for the hours 38, minutes 39, and seconds 41 only at the moment of start. Since the chronograph mechanism 11 is operated with a single pusher 9, hammer 29 must be deactivated for the two subsequent presses, P2 and P3. A hammer rocker 21 allows hammer 29 to be activated or deactivated by pivoting. Furthermore, the clutch must not be engaged simultaneously with hammer 29 pressing the chronograph hearts for the hours 38, minutes 39, and seconds 41, to avoid damaging the gear train, but not too late either, because if the chronograph hands for the hours 66 and minutes 67 are free, the split-seconds function will activate. The seconds hand 8 acts as the chronograph seconds hand when the chronograph mechanism 11 is engaged. This seconds hand 8 must be disengaged the moment the hammer 29 strikes the chronograph seconds heart 41, so as not to strain the finishing gear train (not shown in the figures), which could stop the movement as long as the user presses the pusher 9. The configuration of the chronograph mechanism 11 means that it has three clutches: the clutch-disengagement module 30 with the hour clutch and braking board 52 for the hour chronograph hand 6, the minute clutch and braking board 53 for the minute chronograph hand 7, the clutch- disengagement of the seconds hand 44 with the seconds clutch disc 48. In general, a classic chronograph has only one clutch. The present invention is not limited to the embodiments described and illustrated. Numerous modifications can be made without departing from the scope of the claims. This application describes various technical features and advantages with reference to the figures and / or various embodiments. Those skilled in the art will understand that the technical features of a given embodiment can in fact be combined with features of another embodiment unless the contrary is explicitly stated, or it is obvious that such features are incompatible, or that the combination does not provide a solution to at least one of the technical problems mentioned in this application. Furthermore, the technical features described in a given embodiment can be isolated from the other features of that embodiment unless the contrary is explicitly stated.

Claims

DEMANDS 1. Chronograph mechanism for measuring time comprising a chronograph hour hand (6), a chronograph minute hand (7) and a seconds hand (8), arranged coaxially with a normal hour hand (3) and a normal minute hand (4), the mechanism being characterized in that the chronograph hour hand (6) and the chronograph minute hand (7) are driven synchronously and in a superimposed position, respectively with the normal hour hand (3) and with the normal minute hand (4) to display normal time, the chronograph hour hand (6), the chronograph minute hand (7) and the seconds hand (8) are driven to be positioned at 12 o'clock, before the time measurement, the chronograph hour hand (6), the chronograph minute hand (7) and the seconds hand (8) are driven to measure time, the chronograph hour hand (6),The chronograph minute hand (7) and the seconds hand (8) are locked to display the measured time, and the chronograph hour hand (6) and the chronograph minute hand (7) are repositioned in a superimposed position and re-engaged synchronously, respectively with the normal hour hand (3) and with the normal minute hand (4), after the measured time has been displayed, to display the normal time.

2. Mechanism according to claim 1, wherein the sweep hand serves as a normal seconds hand and as a chronograph seconds hand.

3. Mechanism according to claim 1 or 2, wherein the second hand continues its course after displaying the measured time.

4. Mechanism according to any one of claims 1 to 3, wherein the mechanism is controlled by a pusher (9), the chronograph hour hand (6), the chronograph minute hand (7) and the seconds hand (8) are driven to position themselves at 12 o'clock, following a first actuation of the pusher (9), The chronograph hour hand (6), the chronograph minute hand (7) and the second hand (8) are driven to measure the time, following a release of the pusher (9), the chronograph hour hand (6), the chronograph minute hand (7) and the second hand (8) are blocked to display the measured time, following a second actuation of the pusher (9), the chronograph hour hand (6) and the chronograph minute hand (7) are driven to position themselves in a superimposed position, respectively with the normal hour hand (3) and with the normal minute hand (4), following a third actuation of the pusher (9).

5. Mechanism according to claim 4, wherein the second hand continues its course from its timing position following said third actuation of the pusher (9).

6. A mechanism according to any one of claims 1 to 5, wherein, in a superimposed position, either the chronograph hour hand is below the normal hour hand and the chronograph minute hand is below the normal minute hand, or the chronograph hour hand is on top of the normal hour hand and the chronograph minute hand is on top of the normal minute hand.

7. Mechanism according to any one of claims 1 to 6, wherein the mechanism comprises a split-seconds module (64), equipped with an hour chronograph wheel (66) and a minute chronograph wheel (67), each wheel (66, 67) comprising an hour chronograph core (38) and a minute chronograph core (39), an hour clutch and brake board (52) and a minute chronograph wheel (53), an hour split-seconds wheel (68) and a minute split-seconds wheel (71), which are free on the rotation axis of the hour chronograph wheel (66) and respectively on the rotation axis of the minute wheel (67), and an intermediate hour chronograph wheel (69) and minute chronograph wheel (72).

8. Mechanism according to claim 7, wherein the split-seconds hour (68) and minute (71) wheel and the intermediate chronograph hour (69) and chronograph minute (72) wheel each respectively comprise conjugate drive means such that the split-seconds hour (68) and minute (71) wheel respectively drive the intermediate wheel of the chrono hour (69) and chrono minute (72) hands, so as to superimpose the chrono hour hand (6) and the chrono minute hand (7) respectively with the normal hour hand (3) and with the normal minute hand (4) to display normal time.

9. Mechanism according to any one of claims 1 to 8, wherein the mechanism comprises a hammer actuation module (18), the hammer (29) being able to press on a chrono hour heart (38), on a chrono minute heart (39) and on a chrono second heart (41), so as to position at 12 o'clock the chrono hour hand (6), the chrono minute hand (7) and the seconds hand (8).

10. Mechanism according to claim 9, wherein the hammer comprises an angular portion per core, each angular portion being arranged to bear against a core, at least one of said angular portion comprises a flexible distal part.

11. Mechanism according to any one of claims 1 to 10, wherein the mechanism comprises a clutch-disengagement module (30) for the chronograph hour hand (6) and the chronograph minute hand (7), provided with an hour clutch rocker (31) and a minute clutch rocker (34) which respectively control a chronograph hour oscillating pinion (49) and a chronograph minute oscillating pinion (51) suitable for engaging respectively with an hour clutch and braking board (52) and with a minute clutch and braking board (53), so as to measure time.

12. Mechanism according to any one of claims 1 to 11, wherein the mechanism comprises a locking module including, an hour locker (56) capable of locking an hour clutch and brake board (52), and a minute locker (57), capable of locking a minute clutch and brake board (53), so as to display the measured time.

13. Mechanism according to any one of claims 1 to 12, wherein the mechanism comprises a clutch-disengagement module (44) for the seconds hand (8), equipped with two articulated clamps (45, 46), suitable for engaging and releasing a seconds clutch disc (48).

14. Mechanism according to any one of claims 7 to 13, wherein the hammer actuation module (18), the clutch-disengagement module (30) of the chronograph hour hand (6) and the chronograph minute hand (7), the clutch-disengagement module (44) of the seconds hand (8) and the locking module (51) of the chronograph hour hand (6) and the chronograph minute hand (7), are actuated by a column wheel (12), driven in rotation by a control (14), moved by the pusher (9).

15. Mechanism according to claim 13 or 14, wherein the clutch-disengagement module (44) of the second hand (8) is actuated by a lever moved by a hammer (29), actuated by the hammer actuating module (18).

16. A clock movement comprising a mechanism according to any one of claims 1 to 15.

17. Watch movement according to claim 16, wherein the movement comprises a finishing gear driven by a power source, and wherein the mechanism comprises a clutch module according to claim 9, the finishing gear being engaged with the oscillating hour pinion (49) and the oscillating minute pinion (51) which respectively drive the hour clutch and brake board (52) and the minute clutch and brake board (53) to actuate respectively the chronograph hour hand and the chronograph minute hand so as to measure time.

18. Timepiece comprising a movement according to one of claims 16 or 17 or a mechanism according to one of claims 1 to 15.

19. Timepiece according to claim 18, wherein the timepiece is a watch equipped with a dial (2) on which are mounted the normal hour hand (3), the normal minute hand (4) and the seconds hand (8), the chronograph hour hand (6), the chronograph minute hand (7)

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