CLOCKMOVEMENT INCLUDING A CHRONOGRAPH MECHANISM, IN PARTICULAR WITH FRACTIONAL SECONDS

Description

Technical field of the invention

[0001] The present invention relates to a watch movement comprising a chronograph mechanism.

[0002] The present invention relates to a watch movement comprising a chronograph mechanism featuring a fraction-of-a-second counter.

[0003] More specifically, the invention relates to a chronograph mechanism comprising a mechanism for resetting a fraction-of-a-second counter.

[0004] The invention also relates to a timepiece comprising such a chronograph mechanism. Technological background

[0005] Chronograph mechanisms allow time to be measured on demand via several chronograph counters, for example minutes and seconds.

[0006] Chronograph mechanisms typically include a reset mechanism for resetting the chronograph counters, i.e., repositioning them in a reference position, so that time can be measured again on demand.

[0007] Typically, such a reset mechanism consists of a reset control that can be operated by the user, for example via a pusher, an actuation point accessible from outside the case in which the watch movement is mounted.

[0008] The reset control cooperates directly or indirectly with a reset hammer which strikes the reset cams carried by the various chronograph counters.

[0009] Some complex chronograph mechanisms can be equipped with an additional counter to display fractions of a second.

[0010] It is therefore necessary to plan for a reset of this fraction-of-a-second counter.

[0011] One solution involves using an additional hammer to strike a reset cam on the fraction-second counter. However, this solution further complicates the mechanism and increases the number of parts in the watch movement. Moreover, the presence of a reset cam on the fraction-second counter introduces an additional imbalance that must be managed, particularly when the chronograph is stopped, given the counter's rapid rotation (one revolution per second).

[0012] Another solution was proposed in document CH703797 which eliminates the need for a reset cam on the fraction-second counter.

[0013] This solution involves using a clutch that kinematically connects the escape wheel to the axis of the lightning seconds pinion. The clutch comprises: a first toothed wheel fixed to the escape wheel; a first six-toothed star mounted on the axis of the lightning seconds pinion; a second six-toothed star mounted freely on the axis of the lightning seconds pinion and connected to the first star by a pin driven into the first star and passing through an oblong slot in the second star.

[0014] However, this solution is complex to manufacture and implement. Furthermore, given the configuration of such a system, the chronograph is not precise because it exhibits a one-step delay in the escape wheel corresponding to one alternation of the anchor. Finally, achieving precise positioning of the fraction-seconds display at the zero position is difficult due to manufacturing tolerances.

[0015] Document EP 3 059 642 A1 reveals a chronograph with two power sources: a spring-loaded mechanism for the chronograph function and a conventional power source for the running time. This document also shows the presence of a rocker switch that works in conjunction with the chronograph counter.

[0016] Therefore, there is a need to improve chronograph mechanisms, and in particular chronograph mechanisms featuring a fraction-second counter, as well as to improve the resetting mechanisms for the counters of such chronograph mechanisms. Summary of the invention

[0017] In this context, one of the objectives of the invention is to propose a chronograph mechanism that solves at least one of the problems raised previously.

[0018] One of the objectives of the invention is to provide a reset mechanism that offers a precise reset, in particular of a chronograph fraction-second hand, exactly opposite a predetermined graduation on the dial.

[0019] One of the objectives of the invention is to offer a reliable and secure reset mechanism allowing precise resetting, thus eliminating imbalance problems on chronograph counters with rapid rotations.

[0020] In this context, the invention relates to a clockwork movement comprising a timekeeping gear dedicated to dividing the time of said clockwork movement, said timekeeping gear being driven by a first energy source and regulated by a regulating organ; the clockwork movement comprising a chronograph mechanism including: a chronograph gear driven by a second power source; the chronograph gear comprising a chronograph counter having a counter wheel and a display fixed to rotate with the counter wheel; a chronograph start / stop control device configured to couple the chronograph gear to the regulating organ, or to the timekeeping mechanism, on demand, to regulate the chronograph gear from the regulating organ; a reset mechanism for resetting said chronograph counter comprising a movable reset control between a neutral rest position and a reset position.

[0021] The chronograph mechanism according to the invention further comprising a rocker, movable in rotation about an axis of rotation, configured to cooperate with the chronograph counter; said rocker being configured to be controlled by the chronograph start / stop control device between a first stable position, called the stop position, in which the rocker blocks the rotation and maintains the position of the counter wheel, and a second stable position, called the neutral position, in which the counter wheel is free to rotate;the reset control being configured to cooperate, in the reset position, with the rocker to angularly position the latter in a third intermediate position in which the rocker partially releases the counter wheel so as to allow rotation of the counter wheel until it is positioned in a reset reference position, the counter wheel being driven by the second power source driving the chronograph gear train.;

[0022] In addition to the characteristics mentioned in the preceding paragraph, the watch movement according to the invention may have one or more additional characteristics from among the following, considered individually or in all technically possible combinations: the counter wheel has teeth comprising a long tooth having an end portion radially further from the center of the counter wheel than the other teeth constituting the teeth; the rocker being inserted between two consecutive teeth of the counter wheel teeth in said first stable rocker position to block rotation and maintain the position of the counter wheel, the rocker interacting with the end portion of the long tooth in said third intermediate position to partially release the counter wheel and allow rotation of the counter wheel until the long tooth comes to rest against the rocker, positioning the counter wheel in a zeroing reference position; the counter wheel has asymmetrical or wolf's tooth teeth;The rocker arm comprises a first arm configured to feel different states of the chronograph start / stop control device, a second arm configured to cooperate with the counter wheel, and a third arm configured to cooperate with the reset control; the third arm of the rocker arm cooperates with a recess in the reset control, the recess having a profile configured to guide the rocker arm into said third intermediate position when the reset control is in the reset position; the chronograph mechanism comprises an elastic element configured to return the rocker arm to its first stable position; the chronograph start / stop control device comprises a column wheel configured to drive the rocker arm between its first stable position, called the stop position, and its second stable position, called the neutral position;The counter is a fraction-second counter and the rocker is a lightning bolt rocker; the chronograph gear train includes a seconds counter with a seconds display; the reset mechanism includes a seconds reset organ attached to the seconds display and a reset hammer shaped to cooperate with the seconds reset organ and to generate a driving torque under the action of the reset control until the seconds reset organ is positioned in a reference position; the chronograph gear train includes a minute counter with a minutes display;The reset mechanism comprises a minute reset element integral with the minute display, the reset hammer being shaped to cooperate with the minute reset element and to generate a motor torque under the action of the reset control until the minute reset element is positioned in a reference position; the regulating element comprises a high-frequency oscillator having an oscillation frequency greater than or equal to 5Hz.

[0023] Another aspect of the invention relates to a timepiece comprising such a clockwork movement according to the invention.

[0024] The timepiece is preferably a wristwatch comprising a watch case configured to receive and house the timepiece movement according to the invention. Brief description of the figures

[0025] The aims, advantages and features of the present invention will become apparent from the detailed description below, which refers to the following figures: there figure 1 illustrates schematically and functionally a clockwork mechanism 1 according to the invention; the figure 2 is a schematic plan view representation of the clockwork movement 1 according to the invention comprising a chronograph mechanism in a stopped state before being started; the figure 3 illustrates the same clockwork movement according to the invention with the chronograph mechanism in working order; the figure 4 illustrates the same clockwork movement according to the invention with the chronograph mechanism in a stopped state occurring after the chronograph mechanism has been started; the figure 5illustrates the same clockwork movement according to the invention with the chronograph mechanism in a reset state when the chronograph mechanism reset control is pressed.

[0026] In all figures, common elements bear the same reference numbers unless otherwise specified. Detailed description of the invention

[0027] There figure 1 shows a functional schematic representation of a clockwork movement 1 according to the invention.

[0028] There figure 2 shows a schematic plan view representation of the clockwork movement 1 according to the invention comprising a chronograph mechanism 10.

[0029] There figure 2 particularly represents the chronograph mechanism 10 in a neutral position, that is to say in a stopped state with the chronograph counters in their reference position before the chronograph mechanism was started.

[0030] There figure 3 illustrates the same clockwork movement 1 with the chronograph mechanism 10 in a working state of the chronograph gear train 20.

[0031] There figure 4 illustrates the same clockwork movement 1 with the chronograph mechanism 10 in a stopped state of the chronograph gear train 20, occurring after a start-up of the chronograph mechanism 10.

[0032] There figure 5 illustrates the same clockwork movement 1 with the chronograph mechanism 10 in a reset state of the chronograph gear 20 when the reset control of the chronograph mechanism is pressed.

[0033] With reference to figures 1 to 5 , the clock movement 1 according to the invention classically comprises a plate 2 serving as a support for the various elements of the clock movement 1, in particular a timekeeping gear 100 dedicated to the division of time which is driven by a main energy source 150.

[0034] The energy source 150 is, for example, a barrel constituting an energy reserve to power the timekeeping mechanism.

[0035] In a conventional manner, the timekeeping gear 100 drives the displays of a time display, for example an hour hand 111 cooperating with an hour scale, a minute hand 112 cooperating with a minute scale and a seconds hand 113, or sweep second hand, cooperating with a seconds scale.

[0036] The 100 hour gear is classically regulated by a 120 regulating organ.

[0037] The regulating organ 120 traditionally comprises an oscillator 121 and an escapement 122. The oscillator 121 can be a mechanical or electrical oscillator.

[0038] For example, oscillator 121 is a mechanical balance-spring type oscillator. Such a balance-spring oscillator has, for example, an oscillation frequency between 2.5 and 4 Hz.

[0039] For example, the 121 oscillator is a high-frequency mechanical or electrical oscillator, that is, oscillating at a frequency greater than 4Hz.

[0040] For example, the 121 oscillator is a high-frequency mechanical or electrical oscillator, that is, oscillating at a frequency greater than or equal to 5Hz.

[0041] The chronograph mechanism 10 includes a chronograph gear train 20 which can be kinematically linked, on demand, with the time train 100, via a clutch 50 controlled by a chronograph start / stop control device 30.

[0042] The chronograph start / stop control device 30 is configured to couple on demand the chronograph gear 20 to the regulating organ 120, or to the time gear 100, to regulate the chronograph gear 20 from the regulating organ 120 of the clock movement 1.

[0043] The chronograph start / stop control device 30 comprises a user-operable start / stop control member 31 and a clutch rocker 51 controlled via the actuation of the start / stop control member 31.

[0044] The chronograph gear train 20 is driven by a dedicated secondary energy source 35, different from the main energy source 150 of the timekeeping gear train 100. Thus, the entire chronograph gear train 20 is powered by a secondary energy source 35, independently of the main energy source 150 which drives the timekeeping gear train 100.

[0045] The secondary energy source 35 is, for example, a barrel constituting an energy reserve to power the chronograph gear 20.

[0046] The chronograph gear 20 includes at least one chronograph counter, preferably a fractional second counter 23 or lightning counter, for displaying fractions of a second.

[0047] The chronograph gear train 20 may also include a second chronograph counter, and possibly a third chronograph counter.

[0048] The second chronograph counter is, for example, a 22-second counter, and the third chronograph counter is, for example, a 21-minute counter.

[0049] The chronograph gear 20 can also include an hour counter without departing from the scope of the invention.

[0050] The fractional second counter 23 includes a counter wheel, referred to here as a lightning wheel 231, coupled to a fractional second counter shaft, driving a fractional second display 234, for example a pointer, also called a lightning pointer.

[0051] The minute counter 21 comprises a minute counter wheel 211 coupled to a minute counter shaft, driving a chronograph minute display 214, for example a hand as shown on the figure 1 .

[0052] The seconds counter 22 has a seconds counter wheel 221 coupled to a seconds counter shaft, driving a chronograph seconds display 224, for example a hand.

[0053] In the example of implementation shown in figures 2 to 5The seconds counter 22 is superimposed on the fractional-second counter 23, so that the fractional-second counter tree coincides with the seconds counter tree. For readability, the seconds counter 22 is schematically represented with a dashed line so as not to obscure the fractional-second counter 23. Of course, another configuration is possible without departing from the scope of the invention.

[0054] In a conventional manner, the minute counter wheel 211 and the second counter wheel 221 are mounted by friction on their respective shafts.

[0055] The chronograph gear train 20 may include intermediate chronograph wheels 24, 25, 26 to obtain the desired ratios between the different counters 21, 22, 23 of the chronograph mechanism 10. The chronograph gear train 20 may include more intermediate wheels depending on the needs and architectures of the watch movement 1, as well as the placement of the different chronograph counters on the plate 2.

[0056] In the example shown, the clutch 50 is a differential clutch cooperating with the clutch rocker 51, the clutch rocker allowing one of the inputs of the differential clutch to be blocked on demand depending on the running or stopped state of the chronograph.

[0057] In the example shown, the clutch rocker 51 is configured to block one of the inputs of the differential clutch 50 via an intermediate clutch wheel 53 meshed with the differential clutch 50.

[0058] According to an alternative embodiment, the clutch can be a rocker clutch allowing the pivoting of an intermediate clutch wheel 53.

[0059] According to one embodiment, the clutch is a vertical clutch.

[0060] Thus, the 50 clutch allows you to: to couple the chronograph gear 20 to the time gear 100 and / or to the regulating organ 120 of the clock movement 1 to start the various chronograph counters 21, 22, 23 and regulate them at the rate of the regulating organ 120; to decouple the chronograph gear 20 from the time gear 100 and / or from the regulating organ 120 of the clock movement 1 to stop the chronograph gear 20 and the various displays 214, 224, 234 of the chronograph counters 21, 22, 23.

[0061] Typically, the 50 differential clutch includes: a first input wheel driven by the timekeeping gear train and therefore having a rotation speed regulated by the regulating organ; an output wheel meshed with said chronograph gear train 20, here with an intermediate wheel 27 meshed with the fractional seconds counter 23; a second free-running input wheel cooperating directly or indirectly with the intermediate clutch wheel 53, which can be blocked in rotation by the clutch rocker 51 controlled by the chronograph start / stop control organ 30.

[0062] The clutch 50 also includes a drive assembly configured to rotate the output wheel at said rotational speed of the first input wheel, when the second input wheel is locked in rotation via the clutch rocker 51.

[0063] Preferably, the 50 clutch is a differential ball clutch. Thus, the drive assembly is formed by the cooperation of balls and an elastic element, formed by a spring washer, ensuring the non-slip rolling of the balls on the first input wheel and the output wheel.

[0064] The chronograph start / stop control device 30 includes a column wheel 63 to control the various rockers according to the on or off state of the chronograph.

[0065] In the illustrated embodiment, the chronograph start / stop control unit 31 is configured to set the column wheel 63 in motion each time the user presses it, so that each press of the chronograph start / stop control unit 31 causes the column wheel 63 to rotate one step. Conventionally, the different angular positions of the column wheel 63 allow the movements of the various rockers, levers, etc. of the chronograph mechanism 10 to be coordinated for starting and stopping the chronograph gear train 20, as well as for resetting the various displays 214, 224, 234 of the counters 21, 22, 23 of the chronograph mechanism 10.

[0066] The different angular positions of the column wheel 63 allow the clutch rocker 51 to be controlled between an inactive position in which the clutch rocker 51 is not in contact with the intermediate clutch wheel 53 and an activated position in which the clutch rocker 51 blocks the rotation of the intermediate clutch wheel 53, and therefore the second free-running input wheel of the clutch 50.

[0067] The clutch rocker 51 has a first end 511 configured to cooperate with the column wheel 63, and particularly to feel the position of the column wheel 63 by feeling the presence of a column 631 or an inter-column space 632 of the column wheel 63, and a second end 512, in the form of a beak, configured to cooperate with the teeth of the intermediate clutch wheel 53 according to the position of the first end 511 on a column 631 or in an inter-column space 632.

[0068] Thus, the clutch rocker 51 switches between the inactive position (illustrated in the figure 1 ) in which the first end 511 is in contact with a column 631 and the second end 512 is at a distance from the intermediate clutch wheel 53, and the activated position (illustrated in the figure 2 ) in which the first end 511 of the clutch rocker 51 is housed in an inter-column space 632 and the second end 512 is inserted between two consecutive teeth of the intermediate clutch wheel 53, to block the rotation of the intermediate clutch wheel 53 meshed with the clutch 50.

[0069] The clutch rocker 51 cooperates with an elastic element 54 configured to ensure contact of the first end 511 of the clutch rocker 51 with the column wheel 63.

[0070] Since the operation of a chronograph mechanism 10 with such a column wheel 63 is widely known, there is no need to explain the operation of such a wheel further.

[0071] The chronograph mechanism 10 includes a reset mechanism 40 for the counters 21, 22, 23 of the chronograph gear train 20, and more particularly for the displays 214, 224, 234 associated respectively with these counters 21, 22, 23.

[0072] The reset mechanism 40 includes reset elements 215, 225 attached to the shafts of the chronograph counters 21, 22. The reset elements 215, 225 cooperate conventionally with one or more hammers (not shown) allowing their positioning in a reference position and the resetting of the displays 214, 224 of the counters 21, 22.

[0073] The reset devices 215, 225 of the minute counters 21 and second counters 22 are for example reset cams in the shape of a snail, a heart, or other, whose shape allows repositioning in a reference position of the displays 214, 224, at the end of the stroke of the hammer(s).

[0074] The reset mechanism 40 includes a reset control 60 which can be operated by the user, for example via a push button or an actuation pin 61. The reset control 60 is movable in rotation about an axis of rotation 66 between a neutral rest position and a reset position allowing the reset of the displays 214, 224, 234.

[0075] The reset control 60 cooperates directly or indirectly with the reset hammer or hammers to enable the resetting of the displays 214, 224 of the associated counters 21, 22.

[0076] The reset command to 60 cooperates directly or indirectly with a lightning flip-flop 70 for resetting the fractional second display 234 of the fractional second counter 23.

[0077] In a conventional manner, the reset control 60 can only be operated by the user when the chronograph is stopped, i.e., when the chronograph gear train 20 is stopped, and the column wheel 63 is in a certain angular position allowing the reset control 60 to be switched.

[0078] The reset control 60 cooperates with a reset elastic element 62 configured to reposition the reset control 60 to its neutral rest position between each user activation. The repositioning of the reset control 60, under the elastic effect of the reset elastic element 62, results in the hammer(s) returning to their neutral position.

[0079] The chronograph mechanism 10 features a lightning-fast rocker 70 configured to interact with the fractional second counter 23.

[0080] The reset command to 60 cooperates directly or indirectly with a lightning flip-flop 70 for resetting the fractional second display 234 of the fractional second counter 23.

[0081] The lightning bolt rocker 70 is configured to cooperate with the start / stop control device 30 so as to control the angular position of the lightning bolt rocker 70 as a function of the start or stop of the chronograph gear 20 and therefore of the start or stop of the fractional second counter 23.

[0082] The lightning-fast flip-flop 70 is also configured to cooperate with the reset control 60 to allow a reset of the fractional second counter 23, and more specifically of the fractional second display 234, when the reset control 60 is actuation.

[0083] Thus, the lightning-fast rocker 70 has a dual function. A first function is to hold the fraction-of-a-second display 234 in position when the chronograph is stopped, and a second function is to ensure that the fraction-of-a-second display 234 is repositioned to the reference position when the chronograph is reset by actuating the reset control 60.

[0084] The lightning-fighting rocker 70 is mobile in rotation around a rotation axis 76. The position of the rotation axis 76 can be adjusted by means of an eccentric.

[0085] The chronograph mechanism 10 is configured to angularly position the lightning bolt lever 70 in three positions, ensuring three different actions. These three positions will be described in more detail later in this description.

[0086] The lightning-fast rocker 70 has a first arm 71 configured to cooperate with the chronograph start / stop control device 30 and to feel the different states of the start / stop control device 30.

[0087] More specifically, the first arm 71 has a free end forming a feeler cooperating with the column wheel 63 of the chronograph start / stop control device 30 to position the lightning bolt rocker 70 in two stable positions which form two of the three positions of the lightning bolt rocker 70.

[0088] In a first angular position of the column wheel 63, the feeler of the first arm 71 is positioned in an inter-column space 632 of the column wheel 63, as visible in Figures 1 , 3 And 4, when the chronograph gear 20 is stopped. This position defines the first stable position of the lightning bolt rocker 70, which occurs at the same time as the chronograph mechanism 10 stops.

[0089] In a second angular position of the column wheel 63, the feeler of the first arm 71 is in contact with a column 631 as visible in the figure 2 . This second position defines a second stable position of the lightning bolt rocker 70 occurring at the same time as the start-up of the chronograph gear 20 and its coupling with the time gear 100.

[0090] The lightning-fast rocker 70 has a second arm 72, extending substantially opposite the first arm 71 with respect to the axis of rotation 76. The second arm 72 has an end beak 720 configured to cooperate and block the rotation of the fraction-second counter 23, and more particularly the lightning-fast wheel 231 of the fraction-second counter 23.

[0091] In the first stable position of the 70-volt lightning-fast tilting mechanism, known as the stopping position, illustrated in Figures 1 And 3 , the thunder wheel 231 is blocked in rotation by the end beak 720 of the second arm 72 of the thunder rocker 70 which is inserted between two consecutive teeth of the teeth 233 of the thunder wheel 231.

[0092] In the second stable position of the 70-folding electrostatic tilt, known as the neutral position, as illustrated in the figure 2, the lightning bolt wheel 231 is free and can be driven in rotation by the chronograph gear 20 in order to count fractions of a second.

[0093] The change of position, between the stop and neutral position, of the lightning-fast rocker 70 is controlled by the column wheel 63, itself driven in rotation at each activation of the chronograph start / stop control organ 31.

[0094] Preferably, the thunder wheel 231 has an asymmetrical toothing 233, also called wolf toothing.

[0095] The teeth of the thundering wheel 231 are composed of a series of identical teeth forming a regular set of teeth and a long tooth 232, that is to say, having a greater height than the other teeth of the set of teeth 233. In other words, the long tooth 232 extends radially beyond the regular teeth of the thundering wheel 231.

[0096] The lightning trigger rocker 70 has a third arm 73 configured to cooperate directly or indirectly with the reset control 60 and position the lightning trigger rocker 70 in a third, so-called intermediate position, illustrated more particularly in the figure 4 .

[0097] This third intermediate position of the lightning switch 70 is not a stable position but a position imposed by the angular position of the reset control 60 when it is held partially or totally pressed by the user in the reset position.

[0098] This third arm 73 is used as a lever by the reset control 60 to position the lightning bolt rocker 70 in the intermediate position located angularly between the stop position and the neutral position. This intermediate position can only be reached from the stable stop position of the lightning bolt rocker 70, which locks the lightning bolt counter 23 in position when the chronograph is stopped.

[0099] In this intermediate position of the lightning rocker 70, the end beak 720 is radially further from the center of rotation of the lightning wheel 231 than in the stop position of the lightning rocker 70.

[0100] In this intermediate position of the fluttering rocker 70, the end beak 720 is therefore clear of the regular teeth of the fluttering wheel 231, allowing the fluttering wheel 231 to rotate, but is positioned sufficiently close to the periphery of the fluttering wheel 231 to be in the path of the long tooth 232 and thus be able to interact with the long tooth 232 to block the rotation of the fluttering wheel 231 in a particular position, the reference position. Thus, in this intermediate position of the fluttering rocker 70, the end beak 720 allows a partial rotation of the fluttering wheel 231, that is, less than a full turn, until the fluttering wheel 231 is positioned in the reference position.

[0101] More specifically, in this intermediate position of the lightning rocker 70, the end beak 720 of the lightning rocker 70 constitutes a positioning stop preventing the long tooth 232 from passing beyond the end beak 720, during the rotation of the lightning wheel 231. When the long tooth 232 is in contact with the end beak 720, the lightning wheel 231 is held in its reference position which corresponds to the zero position of the fraction-second display 234.

[0102] To place the lightning toggle 70 in the intermediate position, the reset control 60 has means configured to cooperate with the lightning toggle 70, and more particularly with the third arm 73.

[0103] In the illustrated embodiment, the reset control 60 has a recess 67 configured to receive, guide, and partially house the third arm 73 and act upon it. Contacting the reset control 60 with the third arm 73 causes the lightning bolt rocker 70 to rotate towards its neutral position, thus moving the end beak 720 away from the regular teeth of the lightning bolt wheel 231 and from the center of rotation of the lightning bolt wheel 231, as previously described.

[0104] The lightning toggle 70 cooperates with an elastic lightning toggle 80 configured to return the lightning toggle 70 to its stop position.

[0105] When the reset control 60 is released, the electrostatic spring 80 tends to position the end beak 720 in its stop position, i.e. inserted between two consecutive teeth of the toothing 233, to hold the electrostatic wheel 231 in position until the next start-up of the chronograph mechanism 10.

[0106] The reset mechanism 40 also includes a retaining element 64 to secure the reset mechanism 40 and ensure that the hammer(s) are fully actuated to their reset position. The retaining element 64 is configured to momentarily prevent the activation of the reset control 60, and therefore of the hammer(s), until a certain force is applied to the reset control 60.

[0107] The retaining element 64 is a safety device preventing an undesired reset of the various displays 214, 224, 234 of the counters 21, 22, 23 of the chronograph mechanism 10. The retaining element 64 exhibits a dynamic behavior similar to a mechanical fuse.

[0108] The retaining member 64 comprises a portion fixed to the plate 2 and an elastic portion arranged to exert the retaining force against the actuation of the reset control 60. The elastic portion is configured to deform when a force greater than the retaining force is applied to the reset control 60, thus releasing the full movement of the reset control 60, allowing the hammer to move to its reset position ( figure 4 ). The reset control 60 includes, for example, a stud 65 intended to bear against the elastic portion of the retaining element 64.

[0109] More specifically, the stud 65 is supported at the level of a retaining notch provided at the level of the free end of the elastic portion of the retaining member 64. The retaining notch has a retaining surface and a tipping point beyond which the retaining member 64 allows the rapid and clear activation of the reset control 60 thus allowing the hammer(s) to be fully actuated until the hammer(s) come into contact with the reset cams 215, 225 of the chronograph counters 21, 22 and the repositioning of these cams in their reference position.

[0110] The release of the reset control 60 also actuates the lightning rocker 70, causing a slight rotation towards its neutral position, which slightly moves the end beak 720 of the second arm 72 away from the regular teeth of the lightning wheel 231. The released lightning wheel 231 continues its rotation in the direction of travel, consuming energy from the energy reserve.

[0111] Advantageously, the lightning rocker 70, particularly the third arm 73, and the reset control 60 are configured to first actuate the lightning rocker 70 before the hammer(s) come into contact with the reset cams 215, 225 of the counters 21, 22, so as to ensure a complete reset of the fractional second display 234 before the complete reset of the seconds 224 and minutes 214 displays via the hammer(s). Operation of the chronograph mechanism of the watch movement

[0112] A first activation of the chronograph start / stop control 31 allows the chronograph gear 20 of the chronograph mechanism 10 to be started in the following manner.

[0113] Starting from the neutral position of the clockwork movement 1 illustrated in the figure 1 , a compulsion of the chronograph start / stop control organ 31 causes it to pivot around its axis of rotation, which in turn causes the column wheel 63 to rotate one step, here in the counterclockwise direction, thus modifying the arrangement of the inter-column spaces 632 and the columns 631 of the column wheel 63 in relation to the different rockers of the chronograph mechanism 10.

[0114] During the rotation of the column wheel 63, the clutch rocker 51 pivots to move from its inactive position (illustrated in the figure 1 ) to its activated position (illustrated in the figure 2) so as to block the rotation of the intermediate clutch wheel 53, inducing a blockage of the second free-running input wheel of the clutch 50.

[0115] The locking of the second idler wheel of the clutch 50 allows the chronograph gear 20 to be coupled to the time gear 100 of the clock movement 1, setting the chronograph gear in motion at the rate of the regulating organ 120.

[0116] Simultaneously with the tilting of the clutch rocker arm 51, the rotation of the column wheel 63 causes the tilting of the lightning rod rocker arm 70, which moves from its first stable position (stop position) (illustrated in the figure 1) in which the feeler of the first arm 71 is in an inter-column space 632 of the column wheel 63 and the end beak 720 of the second arm 72 is inserted between two consecutive teeth of the teeth 233 of the fulcrum wheel 231, in its second stable position (neutral position) (illustrated in the figure 2 ) in which the feeler of the first arm 71 is in contact with a column 631 of the column wheel 63 releasing the end beak 720 of the teeth 233 of the thundering wheel 231.

[0117] Thus, the various counters 21, 22, 23 of the chronograph gear 20 are free and driven in rotation at the rate of the regulating organ of the clock movement 1 by the coupling to the time gear 100.

[0118] When the user wishes to stop the chronograph mechanism 10, they activate the chronograph start / stop control organ 31 a second time, which pivots again around its axis of rotation, driving the column wheel 63 by one additional step. In this new position of the column wheel 63, illustrated in the figure 3 The first end 511 of the clutch lever 51 passes back over a column 631, causing the clutch lever 51 to pivot into its inactive position. The second idler wheel of the clutch 50 is thus released, which decouples the chronograph gear 20 from the timekeeping gear 100, bringing the chronograph gear 20 to a stop.

[0119] The probe of the first arm 71 of the lightning-flashing rocker 70 passes into an inter-column space 632 of the column wheel 63, positioning the lightning-flashing rocker 70 in its first stable position (stop position) under the effect of the elastic lightning-flashing member 80, in which the end beak 720 is inserted between two consecutive teeth of the teeth 233 of the lightning-flashing wheel 231, thus blocking the position of the fraction-second display 234.

[0120] This state of chronograph shutdown is particularly illustrated in the figure 3 .

[0121] Conventional additional means (not shown) may also be provided to hold the displays 214, 224 of the various counters 21, 22 of the chronograph mechanism 10 in position when the chronograph is stopped. Such means may be driven by the column wheel 63 by means of additional rocker arms interacting with the various columns 631 and inter-column spaces 632.

[0122] From this state of stop of the chronograph mechanism 10, the user can restart the chronograph by a third time activating the chronograph start / stop control organ 31, again causing the chronograph gear train 20 to start up as described previously with the pivoting of the corresponding rockers.

[0123] From this same state of stopping the chronograph mechanism 10, the user can also reset the various counters 21, 22, 23 of the chronograph gear train 20 by using the reset control 60, this reset being made possible by the position of the column wheel 63.

[0124] When a force greater than the holding force generated by the holding member 64 is applied to the reset control 60, the complete movement of the reset control 60 allows both the position of the lightning lever 70 to be changed so as to position it in its third intermediate position allowing a return to zero of the fractional second display 234, the lightning wheel 231 making a rotation driven by the second energy source 35 of the chronograph gear 20 until the long tooth 232 comes into contact with the end beak 720 of the second arm 72 of the lightning lever 70.

[0125] Simultaneously, the complete movement of the reset control 60 drives the hammer(s) of the chronograph mechanism 10 which strike the various reset organs 215, 225 to reset the various corresponding displays 214, 224 of the chronograph mechanism 10 to the reference position.

[0126] Additionally, activating the reset command 60 can release the position-holding means of the displays 214, 224 of the counters 21, 22.

[0127] When the reset control 60 is released, it returns to the neutral position under the effect of the elastic element 62, bringing the hammer(s) back to the neutral position, optionally repositioning the means for holding the displays 214, 224 of the counters 21, 22 in position to ensure that these displays 214, 224 are held in position, releasing its constraint exerted on the lightning lever 70 which, under the action of the elastic lightning element 80, repositions the end beak 720 between two consecutive teeth of the teeth 233 of the lightning wheel 231 to ensure that the lightning wheel 231 is held in position and thus avoid undesirable effects of fluctuation of the fraction-second display 234 while waiting for the next start-up of the chronograph mechanism 10.

[0128] As depicted in the various figures 2 to 5The chronograph mechanism 10 has been shown and described with a column wheel 63 to control the various movements of the different levers that rest against a column or between two columns. Of course, the chronograph mechanism 10 can also be a cam-driven chronograph mechanism replacing the column wheel 63, without departing from the scope of the invention, to control the different chronograph states.

[0129] The invention has been particularly described with a fraction-of-a-second counter. However, the invention is also applicable to a second, minute, or hour counter without departing from the scope of the invention.

[0130] The invention also relates to a timepiece, for example a wristwatch, comprising such a timepiece movement.

Claims

1. A horological movement (1) comprising a running train (100) dedicated to the division of time of said horological movement (1), said running train (100) being driven by a first power source (150) and regulated by a regulating member (120); the horological movement (1) comprising a chronograph mechanism (10) comprising: - a chronograph train (20) driven by a second power source (35); the chronograph train (20) comprising a chronograph counter (23) having a counter wheel (231) and a display (234) integral in rotation with the counter wheel (231); - a chronograph start / stop control device (30) configured to couple on demand the chronograph train (20) to the regulating member (120), or to the running train (100), to regulate the chronograph train (20) from the regulating member (120); - a reset mechanism (40) for resetting said chronograph counter (23), comprising a reset control (60) movable between a neutral rest position and a reset position; wherein the chronograph mechanism (10) comprises a lever (70), which is rotatable about an axis of rotation (76), configured to cooperate with the chronograph counter (23); said lever (70) being configured to be controlled by the chronograph start / stop control device (30) between a first stable position, referred to as the stop position, wherein the lever (70) blocks the rotation and maintains the position of the counter wheel (231), and a second stable position, referred to as the neutral position, wherein the counter wheel (231) is free to rotate; the reset control (60) being configured to cooperate, in the reset position, with the lever (70) to position the latter angularly in a third intermediate position wherein the lever (70) partially releases the counter wheel (231) so as to authorise rotation of the counter wheel (231) until it is positioned in a reset reference position, the counter wheel (231) being driven by the second power source driving the chronograph train.

2. The horological movement (1) according to the preceding claim, characterised in that the counter wheel (231) has a toothing (233) comprising a long tooth (232) having an end portion radially further from the centre of the counter wheel (231) than the other teeth constituting the toothing (233); the lever (70) being inserted between two consecutive teeth of the toothing (233) of the counter wheel (231) in said first stable position of the lever (70) to block the rotation and maintain the position of the counter wheel (231), the lever (70) interacting with the end portion of the long tooth (232) in said third intermediate position to partially release the counter wheel (231) and allow partial rotation of the counter wheel (231) until the long tooth (232) abuts against the lever (70) positioning the counter wheel in a reset reference position.

3. The horological movement (1) according to one of the preceding claims, characterised in that the counter wheel (231) has an asymmetrical toothing.

4. The horological movement (1) according to one of the preceding claims, characterised in that the lever (70) comprises a first arm (71) configured to sense different states of the chronograph start / stop control device (30), a second arm (72) configured to cooperate with the counter wheel (231), and a third arm (73) configured to cooperate with the reset control (60).

5. The horological movement (1) according to the preceding claim, characterised in that the third arm (73) of the lever (70) cooperates with a recess (67) of the reset control (60), the recess (67) having a profile configured to guide the lever (70) into said third intermediate position when the reset control (60) is in the reset position.

6. The horological movement (1) according to one of the preceding claims, characterised in that the chronograph mechanism (10) comprises an elastic member (80) configured to return the lever (70) to its first stable position.

7. The horological movement (1) according to one of the preceding claims, characterised in that the chronograph start / stop control device (30) comprises a column wheel (63) configured to control the lever (70) between its first stable position, known as the stop position, and its second stable position, known as the neutral position.

8. The horological movement (1) according to one of the preceding claims, characterised in that the counter (23) is a split-second counter and the lever (70) is a jumping lever.

9. The horological movement (1) according to one of the preceding claims, characterised in that the chronograph train (20) comprises a seconds counter (22) comprising a seconds display (224).

10. The horological movement (1) according to the preceding claim, characterised in that the reset mechanism (40) comprises a seconds reset member (225) integral with the seconds display (224) and a reset hammer shaped to cooperate with the seconds reset member (225) and to generate a motor torque under the action of the reset control (60) until the seconds reset member (225) is positioned in a reference position.

11. The horological movement (1)according to one of the preceding claims, characterised in that the chronograph train (20) comprises a minute counter (21) comprising a minute display (214).

12. The horological movement (1) according to the preceding claim, characterised in that the reset mechanism (40) comprises a minute reset member (215) integral with the minute display (214), the reset hammer being shaped to cooperate with the minute reset member (215) and to generate a motor torque under the action of the reset control (60) until the minute reset member (215) is positioned in a reference position.

13. The horological movement (1) according to the preceding claim, characterised in that the regulating member (120) comprises a highfrequency oscillator (121) having an oscillation frequency greater than or equal to 5 Hz.

14. A timepiece comprising a horological movement (1) according to one of the preceding claims.