CH720711A2 - Clock movement comprising a chronograph mechanism, in particular with a jumping second - Google Patents

Abstract

The invention relates to a timepiece movement (1) comprising on the one hand a chronograph mechanism 10 and on the other hand a time train driven by a first energy source and regulated by a regulating member. The chronograph mechanism (10) comprises firstly a chronograph train (20) driven by a second energy source and comprising a chronograph counter (23) having a counter wheel (231), secondly a chronograph start/stop control device (30) configured to couple the chronograph train (20) to the regulating member on demand and thirdly 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. The chronograph mechanism (10) comprises a lever (70) configured to be controlled by the chronograph start/stop control device (30) between a first stable position in which the lever (70) blocks the rotation of the counter wheel (231) and a second stable position in which the counter wheel (231) is free to rotate. The reset control (60) is configured to cooperate with the lever (70) to angularly position the latter in a third intermediate position in which the lever (70) allows rotation of the counter wheel (231) until the latter is positioned in a zero-reset reference position under the effect of the second energy source driving the chronograph gear train.

Description

Technical field of the invention

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

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

[0003] More particularly, 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 by means of 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 to a reference position, so that time can be measured again on demand.

[0007] Conventionally, such a reset mechanism consists of a reset control that can be manipulated by the user, for example via a push button, an actuating stud accessible from the outside of 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 then necessary to provide a reset of this fraction-of-a-second counter.

[0011] One solution is to use an additional hammer to strike a reset cam carried by the fractional second counter. However, such a solution further complicates the mechanism and increases the number of parts in the clockwork movement. In addition, the presence of a reset cam on the fractional second counter creates an additional imbalance that must be managed, particularly when the chronograph is stopped, given the rapid rotation of the counter (1 revolution per second).

[0012] Another solution was notably proposed in document CH703797 making it possible to avoid the use of a reset cam on the fraction-of-a-second counter.

[0013] This solution consists in using a clutch kinematically connecting the escapement wheel to the axis of the jumping seconds pinion. The clutch comprises: a first wolf-toothed wheel secured to the escapement wheel; a first six-tooth star driven onto the axis of the jumping seconds pinion; a second six-tooth star mounted freely on the axis of the jumping 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 has a delay of one step of the escape wheel corresponding to an alternation of the anchor. Finally, it is difficult to obtain precise positioning of the fractions of seconds display in zero position given the manufacturing tolerances.

[0015] Therefore, there is a need for improving chronograph mechanisms, and in particular chronograph mechanisms having a fractional second counter, as well as for improving the counter reset mechanisms of such chronograph mechanisms.

Summary of the invention

[0016] In this context, one of the objectives of the invention is to propose a chronograph mechanism making it possible to resolve at least one of the problems raised above.

[0017] One of the objectives of the invention is to propose a zero-reset mechanism which provides precise zero-reset, in particular of a chronograph fraction-second hand, exactly opposite a predetermined graduation on the dial.

[0018] One of the objectives of the invention is to propose a reliable and secure zero-reset mechanism allowing precise zero-reset making it possible to overcome the problems of imbalance on chronograph counters with rapid rotations.

[0019] In this context, the invention relates to a timepiece movement comprising a time train dedicated to dividing the time of said timepiece movement, said time train being driven by a first energy source and regulated by a regulating member; the timepiece movement comprising a chronograph mechanism comprising: – a chronograph train driven by a second energy source; the chronograph train comprising a chronograph counter having a counter wheel and a display rotationally secured to the counter wheel; – a chronograph start/stop control device configured to couple the chronograph train to the regulating member, or to the time train, on demand to regulate the chronograph train from the regulating member; – a reset mechanism for resetting said chronograph counter comprising a reset control movable between a neutral rest position and a reset position.

[0020] The chronograph mechanism according to the invention further comprising a lever, movable in rotation about an axis of rotation, configured to cooperate with the chronograph counter; said lever being configured to be controlled by the start/stop control device of the chronograph between a first stable position, called the stop position, in which the lever 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 lever to angularly position the latter in a third intermediate position in which the lever partially releases the counter wheel so as to allow rotation of the counter wheel until it is positioned in a zero reset reference position, the counter wheel being driven by the second energy source driving the chronograph gear train.

[0021] In addition to the features mentioned in the preceding paragraph, the timepiece movement according to the invention may have one or more additional features among the following, considered individually or in all technically possible combinations: – the counter wheel has a toothing comprising a long tooth having an end portion radially further from the center of the counter wheel than the other teeth constituting the toothing; the lever being inserted between two consecutive teeth of the toothing of the counter wheel in said first stable position of the lever to block rotation and maintain the position of the counter wheel, the lever 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 into abutment against the lever positioning the counter wheel in a zero-reset reference position; – the counter wheel has asymmetrical or wolf-toothed toothing; – the lever comprises a first arm configured to sense 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 lever cooperates with a recess in the reset control, the recess having a profile configured to guide the lever into said third intermediate position when the reset control is in the reset position; – the chronograph mechanism comprises an elastic member configured to return the lever to its first stable position; – the chronograph start/stop control device comprises a column wheel configured to drive the lever between its first stable position, called the stop position, and its second stable position, called the neutral position; – the counter is a fraction-of-a-second counter and the lever is a foudroyante lever; – the chronograph gear train comprises a seconds counter comprising a seconds display; – the reset mechanism comprises a seconds reset member secured to the seconds display and a reset hammer shaped to cooperate with the seconds reset member and to generate a driving torque under the action of the reset control until the seconds reset member is positioned in a reference position; – the chronograph gear train comprises a minute counter comprising a minute display; – the reset mechanism comprises a minutes reset member secured to the minutes display, the reset hammer being shaped to cooperate with the minutes reset member and to generate a driving torque under the action of the reset control until the minutes reset member is positioned in a reference position; – the regulating member comprises a high-frequency oscillator having an oscillation frequency greater than or equal to 5 Hz.

[0022] Another aspect of the invention relates to a timepiece comprising such a timepiece movement according to the invention.

[0023] 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

[0024] The aims, advantages and characteristics of the present invention will become apparent upon reading the detailed description below, referring to the following figures: - Figure 1 schematically and functionally illustrates a timepiece movement 1 according to the invention; - Figure 2 is a schematic plan view of the timepiece movement 1 according to the invention comprising a chronograph mechanism in a stopped state before starting; - Figure 3 illustrates the same timepiece movement according to the invention with the chronograph mechanism in a running state; - Figure 4 illustrates the same timepiece movement according to the invention with the chronograph mechanism in a stopped state occurring after starting the chronograph mechanism; - Figure 5 illustrates the same timepiece movement according to the invention with the chronograph mechanism in a reset state when the reset control of the chronograph mechanism is pressed.

[0025] In all figures, common elements bear the same reference numbers unless otherwise specified.

Detailed description of the invention

[0026] Figure 1 shows a functional schematic representation of a clock movement 1 according to the invention.

[0027] Figure 2 shows a schematic representation in plan view of the clockwork movement 1 according to the invention comprising a chronograph mechanism 10.

[0028] Figure 2 particularly shows 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 is started.

[0029] Figure 3 illustrates the same clockwork movement 1 with the chronograph mechanism 10 in a running state of the chronograph gear train 20.

[0030] Figure 4 illustrates the same clockwork movement 1 with the chronograph mechanism 10 in a state of stopping of the chronograph gear train 20, occurring after starting of the chronograph mechanism 10.

[0031] Figure 5 illustrates the same timepiece movement 1 with the chronograph mechanism 10 in a state of resetting the chronograph gear train 20 when the chronograph mechanism reset control is pressed.

[0032] With reference to Figures 1 to 5, the clockwork movement 1 according to the invention conventionally comprises a plate 2 serving as a support for the various elements of the clockwork movement 1, in particular for a time train 100 dedicated to the division of time which is driven by a main energy source 150.

[0033] The energy source 150 is for example a barrel constituting an energy reserve for powering the time train.

[0034] Conventionally, the time train 100 drives the displays of a time display, for example an hour hand 111 cooperating with an hour graduation, a minute hand 112 cooperating with a minute graduation and a second hand 113, or second hand, cooperating with a second graduation.

[0035] The hourly gear 100 is conventionally regulated by a regulating organ 120.

[0036] The regulating organ 120 traditionally comprises an oscillator 121 and an escapement 122. The oscillator 121 can be a mechanical or electrical oscillator.

[0037] For example, the oscillator 121 is a mechanical oscillator of the sprung balance type. Such a sprung balance has, for example, an oscillation frequency of between 2.5 and 4 Hz.

[0038] For example, the oscillator 121 is a high-frequency mechanical or electrical oscillator, i.e. oscillating at a frequency greater than 4 Hz.

[0039] For example, the oscillator 121 is a high-frequency mechanical or electrical oscillator, i.e. oscillating at a frequency greater than or equal to 5 Hz.

[0040] The chronograph mechanism 10 comprises a chronograph gear train 20 which can be kinematically connected, and on request, with the time gear train 100, by means of a clutch 50 controlled by a chronograph start/stop control device 30.

[0041] The chronograph start/stop control device 30 is configured to couple on demand the chronograph gear train 20 to the regulating organ 120, or to the time gear train 100, to regulate the chronograph gear train 20 from the regulating organ 120 of the timepiece movement 1.

[0042] The chronograph start/stop control device 30 comprises a start/stop control member 31 which can be manipulated by the user and a clutch lever 51 controlled via the actuation of the start/stop control member 31.

[0043] The chronograph gear train 20 is driven by a dedicated secondary energy source 35, different from the main energy source 150 of the time 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 actuating the time gear train 100.

[0044] The secondary energy source 35 is for example a barrel constituting an energy reserve for powering the chronograph gear train 20.

[0045] The chronograph gear train 20 comprises at least one chronograph counter, preferably a fraction-of-a-second counter 23 or foudroyante counter, for displaying fractions of a second.

[0046] The chronograph gear train 20 may also include a second chronograph counter, and possibly a third chronograph counter.

[0047] The second chronograph counter is for example a 22 seconds counter, and the third chronograph counter is for example a 21 minutes counter.

[0048] The chronograph gear train 20 may also include an hour counter without departing from the scope of the invention.

[0049] The fractional second counter 23 comprises a counter wheel, here called a lightning wheel 231, coupled to a fractional second counter shaft, driving a fractional second display 234, for example a needle, also called a lightning needle.

[0050] 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 in FIG. 1.

[0051] The seconds counter 22 comprises a seconds counter wheel 221 coupled to a seconds counter shaft, driving a chronograph seconds display 224, for example a hand.

[0052] In the embodiment shown in FIGS. 2 to 5, the seconds counter 22 is superimposed with the fractions of a second counter 23, so that the fractions of a second counter shaft is merged with the seconds counter shaft. For greater readability, the seconds counter 22 is schematically shown in dotted lines so as not to mask the fractions of a second counter 23. Of course, another configuration is possible without departing from the context of the invention.

[0053] Conventionally, the minute counter wheel 211 and the second counter wheel 221 are frictionally mounted on their respective shafts.

[0054] 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 timepiece movement 1, as well as the location of the different chronograph counters on the plate 2.

[0055] In the example shown, the clutch 50 is a differential clutch cooperating with the clutch lever 51, the clutch lever making it possible to block one of the inputs of the differential clutch on demand depending on the running or stopping state of the chronograph.

[0056] 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.

[0057] According to an alternative embodiment, the clutch may be a rocking clutch allowing the pivoting of an intermediate clutch wheel 53.

[0058] According to an alternative embodiment, the clutch is a vertical clutch.

[0059] Thus, the clutch 50 makes it possible to: – couple the chronograph gear train 20 to the time gear train 100 and/or to the regulating organ 120 of the timepiece movement 1 to start the various chronograph counters 21, 22, 23 and regulate them at the rate of the regulating organ 120; – decouple the chronograph gear train 20 from the time gear train 100 and/or from the regulating organ 120 of the timepiece movement 1 to stop the chronograph gear train 20 and the various displays 214, 224, 234 of the chronograph counters 21, 22, 23.

[0060] Conventionally, the differential clutch 50 comprises: – a first input wheel driven by the time train and therefore having a rotation speed regulated by the regulating member; – an output wheel meshed with said chronograph train 20, here with an intermediate wheel 27 meshed with the fraction-of-second counter 23; – a second idle input wheel cooperating directly or indirectly with the intermediate clutch wheel 53, which can be blocked in rotation by the clutch lever 51 controlled by the chronograph start/stop control member 30.

[0061] The clutch 50 also comprises a drive assembly configured to rotate the output wheel at said rotation speed of the first input wheel, when the second input wheel is blocked in rotation via the clutch lever 51.

[0062] Preferably, the clutch 50 is a ball differential clutch. Thus, the drive assembly is formed by the cooperation of balls and an elastic element, formed by a spring washer, ensuring the rolling without slipping of the balls on the first input wheel and the output wheel.

[0063] The chronograph start/stop control device 30 comprises a column wheel 63 for controlling the various levers depending on the start or stop state of the chronograph.

[0064] In the illustrated embodiment, the chronograph start/stop control member 31 is configured to set the column wheel 63 in motion each time the user presses it, such that each press of the chronograph start/stop control member 31 causes the column wheel 63 to rotate by one step. Conventionally, the different angular positions of the column wheel 63 make it possible to coordinate the movements of the different levers, levers, etc. of the chronograph mechanism 10 for starting and stopping the chronograph gear train 20, as well as to allow the different displays 214, 224, 234 of the counters 21, 22, 23 of the chronograph mechanism 10 to be reset to zero.

[0065] The different angular positions of the column wheel 63 make it possible to control the clutch lever 51 between a non-activated position in which the clutch lever 51 is not in contact with the intermediate clutch wheel 53 and an activated position in which the clutch lever 51 blocks the rotation of the intermediate clutch wheel 53, and therefore the second idle input wheel of the clutch 50.

[0066] The clutch lever 51 comprises a first end 511 configured to cooperate with the column wheel 63, and particularly to sense the position of the column wheel 63 by sensing 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 as a function of the position of the first end 511 on a column 631 or in an inter-column space 632.

[0067] Thus, the clutch lever 51 switches between the non-activated position (illustrated in FIG. 1) in which the first end 511 is in contact with a column 631 and the second end 512 at a distance from the intermediate clutch wheel 53, and the activated position (illustrated in FIG. 2) in which the first end 511 of the clutch lever 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.

[0068] The clutch rocker 51 cooperates with an elastic member 54 configured to ensure contact of the first end 511 of the clutch rocker 51 with the column wheel 63.

[0069] The operation of a chronograph mechanism 10 with such a column wheel 63 being widely known, it is not necessary to further explain the operation of such a wheel.

[0070] The chronograph mechanism 10 comprises a mechanism 40 for resetting the counters 21, 22, 23 of the chronograph train 20, and more particularly the displays 214, 224, 234 associated respectively with these counters 21, 22, 23.

[0071] The reset mechanism 40 comprises reset members 215, 225 secured to the shafts of the chronograph counters 21, 22. The reset members 215, 225 conventionally cooperate with one or more hammers (not shown) allowing them to be positioned in a reference position and the reset of the displays 214, 224 of the counters 21, 22.

[0072] The reset members 215, 225 of the minute counters 21 and seconds counters 22 are, for example, reset cams in the shape of a snail, heart, or other, the shape of which allows repositioning in a reference position of the displays 214, 224, at the end of the stroke of the hammer(s).

[0073] The reset mechanism 40 comprises a reset control 60 that can be manipulated by the user, for example via a push button or an actuating pad 61. The reset control 60 is rotatable about an axis of rotation 66 between a neutral rest position and a reset position allowing the displays 214, 224, 234 to be reset.

[0074] The reset command 60 cooperates directly or indirectly with the reset hammer or hammers to enable the reset of the displays 214, 224 of the associated counters 21, 22.

[0075] The reset command to 60 cooperates directly or indirectly with a lightning trigger 70 for resetting the fraction-second display 234 of the fraction-second counter 23.

[0076] Conventionally, the reset control 60 can be actuated by the user only when the chronograph is stopped, that is to say when the chronograph gear train 20 is stopped, and when the column wheel 63 is in a certain angular position allowing the reset control 60 to tilt.

[0077] The reset control 60 cooperates with an elastic reset element 62 configured to reposition the reset control 60 in a neutral rest position between each user request. The repositioning of the reset control 60, under the elastic effect of the elastic reset element 62, causes the repositioning of the hammer(s) in their neutral position.

[0078] The chronograph mechanism 10 comprises a foudroyante lever 70 configured to interact with the fraction-of-a-second counter 23.

[0079] The reset command to 60 cooperates directly or indirectly with a lightning trigger 70 for resetting the fraction-second display 234 of the fraction-second counter 23.

[0080] The foudroyante lever 70 is configured to cooperate with the start/stop control device 30 so as to control the angular position of the foudroyante lever 70 as a function of the running or stopping of the chronograph gear train 20 and therefore the running or stopping of the fraction-of-a-second counter 23.

[0081] The lightning trigger 70 is also configured to cooperate with the reset control 60 to allow a reset of the fraction-second counter 23, and more particularly of the fraction-second display 234, when the reset control 60 is actuated.

[0082] Thus, the lightning lever 70 has a dual function. A first function consists in holding the fraction-of-a-second display 234 in position when the chronograph is stopped and a second function consists in ensuring repositioning in the reference position of the fraction-of-a-second display 234 when the chronograph is reset to zero by actuation of the reset control 60.

[0083] The lightning rocker 70 is rotatable about an axis of rotation 76. The position of the axis of rotation 76 can be adjusted by means of an eccentric.

[0084] The chronograph mechanism 10 is configured to angularly position the foudroyante lever 70 in three positions ensuring three different actions. These three positions will be described in more detail in the remainder of the description.

[0085] The lightning lever 70 comprises a first arm 71 configured to cooperate with the chronograph start/stop control device 30 and sense the different states of the start/stop control device 30.

[0086] More particularly, 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 foudroyante lever 70 in two stable positions which form two of the three positions of the foudroyante lever 70.

[0087] 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 FIGS. 1, 3 and 4, when the chronograph gear train 20 is stopped. This position defines the first stable position of the foudroyante lever 70 occurring at the same time as the stopping of the chronograph mechanism 10.

[0088] 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 FIG. 2. This second position defines a second stable position of the lightning lever 70 occurring at the same time as the starting of the chronograph gear train 20 and its coupling with the time gear train 100.

[0089] The lightning lever 70 comprises a second arm 72, extending substantially opposite the first arm 71 relative to the axis of rotation 76. The second arm 72 comprises an end beak 720 configured to cooperate and block the rotation of the fraction-of-second counter 23, and more particularly the lightning wheel 231 of the fraction-of-second counter 23.

[0090] In the first stable position of the lightning rocker 70, called the stop position, illustrated in FIGS. 1 and 3, the lightning wheel 231 is blocked in rotation by the end beak 720 of the second arm 72 of the lightning rocker 70 which is inserted between two consecutive teeth of the toothing 233 of the lightning wheel 231.

[0091] In the second stable position of the lightning lever 70, called the neutral position, as illustrated in FIG. 2, the lightning wheel 231 is free and can be driven in rotation by the chronograph gear train 20 so as to count the fractions of a second.

[0092] The change of position, between the stop and neutral positions, of the lightning lever 70 is controlled by the column wheel 63, itself driven in rotation with each request of the chronograph start/stop control member 31.

[0093] Preferably, the lightning wheel 231 has an asymmetrical toothing 233, also called a wolf toothing.

[0094] The teeth of the lightning wheel 231 are composed of a series of identical teeth forming a regular toothing and a long tooth 232, that is to say having a greater height than the other teeth of the toothing 233. In other words, the long tooth 232 extends radially beyond the regular toothing of the lightning wheel 231.

[0095] The lightning lever 70 comprises a third arm 73 configured to cooperate directly or indirectly with the reset control 60 and position the lightning lever 70 in a third position, called intermediate, illustrated more particularly in FIG. 4.

[0096] This third intermediate position of the lightning lever 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 completely pressed by the user in the reset position.

[0097] This third arm 73 is used as a lever by the reset control 60 to position the foudroyante lever 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 foudroyante lever 70 locking the foudroyante counter 23 in position when the chronograph is stopped.

[0098] In this intermediate position of the lightning lever 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 lever 70.

[0099] In this intermediate position of the lightning rocker 70, the end beak 720 is therefore disengaged from the regular toothing of the lightning wheel 231, allowing a rotation of the lightning wheel 231, but is in a position sufficiently close to the periphery of the lightning wheel 231 to be on the path of the long tooth 232 and thus to be able to interact with the long tooth 232 to block the rotation of the lightning wheel 231 in a particular position, the reference position. Thus, in this intermediate position of the lightning rocker 70, the end beak 720 allows a partial rotation of the lightning wheel 231, that is to say less than a complete turn, until positioning the lightning wheel 231 in the reference position.

[0100] More particularly, in this intermediate position of the lightning lever 70, the end beak 720 of the lightning lever 70 constitutes a positioning stop preventing the passage of the long tooth 232 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 maintained in its reference position which corresponds to the zero position of the fractions of a second display 234.

[0101] To place the lightning rocker 70 in the intermediate position, the reset control 60 has means configured to cooperate with the lightning rocker 70, and more particularly with the third arm 73.

[0102] In the illustrated embodiment, the reset control 60 comprises a recess 67 configured to receive, guide and partially house the third arm 73 and act on it. The contacting of the reset control 60 with the third arm 73 is accompanied by a rotation of the lightning rocker 70 towards its neutral position so as to move the end beak 720 away from the regular toothing of the lightning wheel 231 and from the center of rotation of the lightning wheel 231, as indicated above.

[0103] The lightning rocker 70 cooperates with an elastic lightning member 80 configured to return the lightning rocker 70 to its stop position.

[0104] When the reset control 60 is released, the elastic lightning member 80 tends to position the end beak 720 in its stop position, that is to say inserted between two consecutive teeth of the toothing 233, to hold the lightning wheel 231 in position until the next start of the chronograph mechanism 10.

[0105] The reset mechanism 40 also comprises a retaining member 64 for securing the reset mechanism 40 and ensuring complete actuation of the hammer(s) to their reset position. The retaining member 64 is configured to momentarily retain the actuation of the zeroing control 60, and therefore of the hammer(s), as long as a certain force is not applied to the zeroing control 60.

[0106] The retaining member 64 is a safety member preventing an unwanted resetting of the various displays 214, 224, 234 of the counters 21, 22, 23 of the chronograph mechanism 10. The retaining member 64 exhibits dynamic behavior similar to a mechanical fuse.

[0107] The retaining member 64 comprises a portion secured 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, thereby releasing the complete movement of the reset control 60 allowing the movement of the hammer to its reset position (FIG. 4). The reset control 60 comprises, for example, a stud 65 intended to bear on the elastic portion of the retaining member 64.

[0108] More particularly, the stud 65 bears at a retaining notch provided at the free end of the elastic portion of the retaining member 64. The retaining notch has a retaining surface and a tilting point beyond which the retaining member 64 allows rapid and direct actuation 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 these cams are repositioned in their reference position.

[0109] The release of the reset control 60 also actuates the lightning rocker 70 generating a slight rotation towards its neutral position, which slightly separates the end beak 720 of the second arm 72 from the regular toothing of the lightning wheel 231. The released lightning wheel 231 continues its rotation in the direction of travel while consuming energy from the energy reserve.

[0110] Advantageously, the lightning lever 70, particularly the third arm 73, and the reset control 60 are configured to first actuate the lightning lever 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 fractions of a second display 234 before the complete reset of the seconds 224 and minutes 214 displays via the hammer(s).

How the chronograph mechanism of the clock movement works

[0111] A first request of the chronograph start/stop control 31 makes it possible to start the chronograph gear train 20 of the chronograph mechanism 10 in the following manner.

[0112] From the neutral position of the clockwork movement 1 illustrated in FIG. 1, a request to the chronograph start/stop control member 31 causes it to pivot about its axis of rotation, the latter causing 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 relative to the different levers of the chronograph mechanism 10.

[0113] Upon rotation of the column wheel 63, the clutch rocker 51 tilts from its non-activated position (shown in FIG. 1) to its activated position (shown in FIG. 2) so as to block rotation of the intermediate clutch wheel 53, thereby causing the second idler input wheel of the clutch 50 to become blocked.

[0114] Blocking the second idle input wheel of the clutch 50 makes it possible to couple the chronograph gear train 20 to the time gear train 100 of the clockwork movement 1, setting the chronograph gear train in motion at the rate of the regulating organ 120.

[0115] Simultaneously with the tilting of the clutch lever 51, the rotation of the column wheel 63 causes the lightning lever 70 to tilt, which passes from its first stable position (stop position) (illustrated in FIG. 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 toothing 233 of the lightning wheel 231, to its second stable position (neutral position) (illustrated in FIG. 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 toothing 233 of the lightning wheel 231.

[0116] Thus, the various counters 21, 22, 23 of the chronograph gear train 20 are free and driven in rotation at the rate of the regulating organ of the clockwork movement 1 by the coupling to the time gear train 100.

[0117] When the user wishes to stop the chronograph mechanism 10, he/she activates the chronograph start/stop control member 31 a second time, which pivots once again about its axis of rotation, rotating the column wheel 63 by an additional step. In this new position of the column wheel 63 illustrated in FIG. 3, the first end 511 of the clutch lever 51 passes back onto a column 631, causing the clutch lever 51 to tilt into its non-activated position. The second idle input wheel of the clutch 50 is therefore released, which decouples the chronograph gear train 20 from the time gear train 100, stopping the chronograph gear train 20.

[0118] The feeler of the first arm 71 of the lightning lever 70 passes through an inter-column space 632 of the column wheel 63 positioning the lightning lever 70 in its first stable position (stop position) under the effect of the lightning elastic member 80, in which the end beak 720 is inserted between two consecutive teeth of the toothing 233 of the lightning wheel 231 thus blocking the position of the fractions of a second display 234.

[0119] This state of stopping the chronograph is particularly illustrated in figure 3.

[0120] Conventional additional means (not shown) may also be provided to maintain in position the displays 214, 224 of the various counters 21, 22 of the chronograph mechanism 10 in this stopped state of the chronograph. Such means may be controlled by the column wheel 63 by means of additional levers interacting with the various columns 631 and inter-column spaces 632.

[0121] From this state of stopping of the chronograph mechanism 10, the user can restart the chronograph by activating the chronograph start/stop control member 31 a third time, again causing the chronograph gear train 20 to start as described previously with the corresponding pivoting of the levers.

[0122] From this same stopping state of the chronograph mechanism 10, the user can also reset the various counters 21, 22, 23 of the chronograph gear train 20 by requesting the reset command 60, this reset being permitted by the position of the column wheel 63.

[0123] When a force greater than the retaining force generated by the retaining member 64 is applied to the reset control 60, the complete movement of the reset control 60 makes it possible to modify the position of the foudroyante lever 70 so as to position it in its third intermediate position allowing a return to zero of the fractions of a second display 234, the foudroyante wheel 231 performing a rotation driven by the second energy source 35 of the chronograph gear train 20 until the long tooth 232 comes into contact with the end beak 720 of the second arm 72 of the foudroyante lever 70.

[0124] Simultaneously, the complete movement of the reset control 60 drives the hammer(s) of the chronograph mechanism 10 to strike the various reset members 215, 225 to return the various corresponding displays 214, 224 of the chronograph mechanism 10 to the reference position.

[0125] In a complementary manner, the actuation of the reset control 60 can release the means for holding the displays 214, 224 of the counters 21, 22 in position.

[0126] When the reset control 60 is released, it returns to the neutral position under the effect of the elastic member 62, returning the hammer(s) 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, releases its stress exerted on the lightning lever 70 which, under the action of the elastic lightning member 80, repositions the end beak 720 between two consecutive teeth of the toothing 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 fractions of a second display 234 while waiting for the next start of the chronograph mechanism 10.

[0127] As shown in the various figures 2 to 5, the chronograph mechanism 10 has been shown and described with a column wheel 63 to control the various movements of the various levers which are supported against a column or between two columns. Of course, the chronograph mechanism 10 can also be a chronograph mechanism with cams replacing the column wheel 63 without departing from the context of the invention, to control the various states of the chronograph.

[0128] The invention has been particularly described with a fraction-of-a-second counter. However, the invention is also applicable to a seconds, minutes or hours counter without departing from the scope of the invention.

[0129] The invention also relates to a timepiece, for example a wristwatch, comprising such a timepiece movement.

Claims (14)

1. A clockwork movement (1) comprising a time train (100) dedicated to dividing the time of said clockwork movement (1), said time train (100) being driven by a first energy source (150) and regulated by a regulating member (120); the clockwork movement (1) comprising a chronograph mechanism (10) comprising: – a chronograph train (20) driven by a second energy source (35); the chronograph train (20) comprising a chronograph counter (23) having a counter wheel (231) and a display (234) rotationally secured to the counter wheel (231); – a chronograph start/stop control device (30) configured to couple on demand the chronograph gear train (20) to the regulating organ (120), or to the time gear train (100), to regulate the chronograph gear train (20) from the regulating organ (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; said timepiece movement (1) being characterized in that the chronograph mechanism (10) comprises a lever (70), movable in rotation about an axis of rotation (76), configured to cooperate with the chronograph counter (23); said rocker (70) being configured to be controlled by the chronograph start/stop control device (30) between a first stable position, called the stop position, in which the rocker (70) blocks rotation and maintains the position of the counter wheel (231), and a second stable position, called the neutral position, in which the counter wheel (231) is free to rotate; the reset control (60) being configured to cooperate, in the reset position, with the rocker (70) to angularly position the latter in a third intermediate position in which the rocker (70) partially releases the counter wheel (231) so as to allow rotation of the counter wheel (231) until positioning the latter in a zero reset reference position, the counter wheel (231) being driven by the second energy source driving the chronograph gear train. 2. Clock movement (1) according to the preceding claim, characterized in that the counter wheel (231) has a toothing (233) comprising a long tooth (232) having an end portion radially further from the center of the counter wheel (231) than the other teeth constituting the toothing (233); the rocker (70) being inserted between two consecutive teeth of the toothing (233) of the counter wheel (231) in said first stable position of the rocker (70) to block the rotation and maintain the position of the counter wheel (231), the rocker (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 a partial rotation of the counter wheel (231) until the long tooth (232) comes into abutment against the rocker (70) positioning the counter wheel in a zero-reset reference position. 3. Clock movement (1) according to one of the preceding claims, characterized in that the counter wheel (231) has asymmetrical teeth. 4. Clockwork movement (1) according to one of the preceding claims, characterized 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. Clockwork movement (1) according to the preceding claim, characterized in that the third arm (73) of the lever (70) cooperates with a recess (67) of the zero-reset control (60), the recess (67) having a profile configured to guide the lever (70) into said third intermediate position when the zero-reset control (60) is in the zero-reset position. 6. Clockwork movement (1) according to one of the preceding claims, characterized in that the chronograph mechanism (10) comprises an elastic member (80) configured to return the lever (70) to its first stable position. 7. Clockwork movement (1) according to one of the preceding claims, characterized 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, called the stop position, and its second stable position, called the neutral position. 8. Clock movement (1) according to one of the preceding claims, characterized in that the counter (23) is a fraction of a second counter and the lever (70) is a lightning lever. 9. Clock movement (1) according to one of the preceding claims, characterized in that the chronograph gear train (20) comprises a seconds counter (22) comprising a seconds display (224). 10. Clock movement (1) according to the preceding claim, characterized in that the zero-reset mechanism (40) comprises a seconds zero-reset member (225) secured to the seconds display (224) and a zero-reset hammer shaped to cooperate with the seconds zero-reset member (225) and to generate a driving torque under the action of the zero-reset control (60) until the seconds zero-reset member (225) is positioned in a reference position. 11. Clock movement (1) according to one of the preceding claims, characterized in that the chronograph gear train (20) comprises a minute counter (22) comprising a minute display (224). 12. Clock movement (1) according to the preceding claim, characterized in that the zero-reset mechanism (40) comprises a minute-reset member (215) secured to the minute display (214), the zero-reset hammer being shaped to cooperate with the minute-reset member (215) and to generate a driving torque under the action of the zero-reset control (60) until the minute-reset member (215) is positioned in a reference position. 13. Clock movement (1) according to the preceding claim, characterized in that the regulating member (120) comprises a high-frequency oscillator (121) having an oscillation frequency greater than or equal to 5 Hz. 14. Timepiece comprising a timepiece movement (1) according to one of the preceding claims.