EP3032358A1 - Chronograph mechanism for a clock movement - Google Patents

Abstract

The present invention relates to a chronograph mechanism, for a watch movement (1), comprising a driving mobile capable of being rotated by a driving wheel for driving on demand a driven wheel (10, 20). ) via a transmission wheel (38, 42, 142), the driven wheel (10, 20) being for controlling the movements of a display member, each driving wheel, driving, transmission (38, 42, 142) and driven (10, 20) having a shaft (72, 78, 82) integral with a first wheel (11, 40, 68). At least one of the driving, transmitting (38, 42, 142) and driven (10, 20) mobiles comprises a second wheel (70, 76) frictionally mounted on the corresponding shaft (72, 78) and arranged to cooperate with the first wheel (11, 21) of another mobile (10, 20) among the drive, driving, transmission (38, 42, 142) and driven (10, 20).

Description

Technical area

The present invention relates to a chronograph mechanism, for a watch movement, comprising a driving mobile capable of being rotated by a driving wheel for driving on demand a mobile driven via a mobile transmission, the drive wheel itself being intended to be driven from a power source of the watch movement, the driven mobile being intended to control the movements of a display member, each mobile driving, driving, transmission and driven having a shaft integral with a first wheel.

State of the art

Chronograph mechanisms including gear wheels of this type are well known in the field of watchmaking. A conventional example is presented in the book entitled " Theory of Clocks ", by C.-A.Reymondin et al., Published by the Federation of Technical Schools (Switzerland), ISBN 2-940025-10-X, especially pages 232-237 .

These chronograph mechanisms have a large number of mobile components interacting with each other and their development is very complex.

In particular, a difficulty recognized in the design of these mechanisms lies in the development of a clutch device allowing in particular to limit as much as possible a jump of the chronograph hand when setting into operation the measurement of 'a time, as explained on pages 234-235 of the work cited above. To limit the amplitude of this jump, it is common to provide a large set of gear between the wheel of the clutch and the chronograph seconds counter wheel with which it meshes. However, the presence of such a set of gear requires the establishment of a friction spring on the mobile seconds chronograph to avoid a kinking of the corresponding display needle. In addition, triangular profile teeth are generally provided on these two wheels to attempt to address the problems just mentioned, but such a tooth profile results in poor transmission of forces between these wheels. These known solutions in particular have an adverse impact on the progress of the watch movement.

Other solutions have been proposed, either by the implementation of particular tooth profiles, as for example in the patent EP 1437633 B1 or by implementing different constructions of the clutch device, as for example in the patent application EP 2112564 A1 which has a complex construction with a differential gear.

These alternative, unconventional solutions are complex and expensive. Thus, there is still a need to find an alternative approach for producing a chronograph mechanism that is simple to implement and that at least partially addresses at least some of the problems mentioned above.

Disclosure of the invention

A main object of the present invention is to propose an alternative construction of a chronograph mechanism of the type which has just been described, presenting few modifications with reference to known constructions, while using conventional type components, but allowing at least partly to address the above problems.

To this end, the present invention relates more particularly to a chronograph mechanism of the type mentioned above, characterized in that at least one of the driving, transmission and driven mobiles comprises a second wheel frictionally mounted on the shaft. corresponding and arranged to cooperate with the first wheel of another mobile among the driving mobiles, driving, transmission and led.

Thanks to these characteristics, the second wheel can rotate freely on its shaft when the value of the torque to be transmitted exceeds a predefined value.

Such an eventuality can occur essentially in two cases in the chronograph wheel, in a non-limiting way.

On the one hand, the implementation of the above features, in connection with a conventional construction chronograph gear clutch device, at least partially solves the problems mentioned above. Indeed, for example, in the case of a conventional chronograph mechanism in which reset hammers are pressed on the heart cams of the stop chronograph mobiles, it is necessary to synchronize perfectly the passage of the clutch from its disengaged state to its engaged state with the lifting of the hammers releasing the chronograph mobiles. The mobile mounted on the clutch rocker here plays the role of mobile transmission between a wheel field and mobile seconds chronograph. In this case, the introduction of a wheel frictionally mounted on its shaft in the chronograph train, according to the present invention, makes it possible to lift the hammers only after the change of position of the clutch and to avoid especially the jump of the second chronograph hand when starting the measurement of a time. Any discrepancy between the teeth of the wheels of the clutch and the chronograph mobile is thus caught up by the friction, without impact on the position of the display needle.

Thus, it will be noted that, in general, the second wheel can be frictionally mounted on the shaft of the transmission wheel and be arranged to cooperate with the first wheel of the driven wheel, while the first wheel of the transmission wheel is arranged. to cooperate with the first wheel of the moving mobile.

In other words, to return to the particular case mentioned above, the second wheel can be frictionally mounted on the shaft of the clutch mobile to cooperate with the wheel of the mobile chronograph seconds, while the first wheel (conventional) mobile clutch cooperates with the wheel on fields.

It is also possible to provide, alternatively, that the second wheel is mounted frictionally on the shaft of the driven mobile and is arranged to cooperate with the wheel of the transmission mobile while the first wheel of the driven mobile is intended to control the movements of a display member.

In other words, to return to the particular case mentioned above, the second wheel can be mounted frictionally on the mobile shaft of the second chronograph being arranged to cooperate with the wheel of the clutch mobile, the latter cooperating itself with the wheel on fields, in a conventional way.

On the other hand, it may be desirable to decouple a mobile from the rest of the chronograph train during the resetting of the measured time. Indeed, during this operation, the reset hammers fall on the heart cams carried by chronograph mobiles seconds, minutes and possibly hours, to rotate quickly and reposition the display members in their rest position. In addition to the fact that mobiles turn quickly, they do not necessarily all turn in the same direction, hence the need to decouple some mobiles from each other. In particular, the minute chronograph mobile is generally driven by jumps from the chronograph mobile seconds when measuring a time. This training is typically performed by a finger arranged in such a way that it can retract during the reset, if necessary. Thus, the construction according to the present invention makes it possible, for example, to implement a simplified construction for driving the minute chronograph mobile, having a kinematic connection, from a driving mobile, in which is involved a wheel mounted rubbing on his tree.

According to a preferred embodiment, the mobile minute chronograph can be driven from the mobile center of the watch movement which is associated with the chronograph mechanism according to the invention. In this case, the mobile center performs the role of mobile leading to the mobile chronograph minutes, it advantageously leads via a mobile transmission comprising an intermediate mobile. The intermediate mobile or mobile minutes of chronograph then advantageously comprises a wheel frictionally mounted on its shaft.

Alternatively, the mobile driving the drive of the mobile chronograph minutes can be a mobile seconds chronograph, this training being performed via an intermediate mobile comprising a shaft to be pivotally mounted on the corresponding watch movement and carrying a wheel friction assembly.

In general, the first and second wheels may advantageously each have a toothing having an NIHS 20-25 toothing profile. This profile, conventional in the workings other than those of the chronograph mechanisms, ensures better performance than the triangular profiles generally used in particular between the clutch wheel and the wheel of the mobile seconds chronograph. In addition, the use of such a tooth profile avoids a clogging of the second display needle of the measured times without having to use the conventional friction spring.

Preferably, the second wheel (frictionally assembled on its shaft) and the first wheel with which it cooperates each have a micro-module toothing. In addition, the first wheels associated with wheels other than the second wheel preferably each have a small module toothing.

Furthermore, the present invention also relates to a chronograph mechanism having the characteristics mentioned above and comprising
a core cam intended to be integral in rotation with the display member,
a reset hammer having a suitable surface for cooperating with the core cam,
a brake for, in the operating position, maintaining fixed the angular position of a wheel of the mobile driven integral with the cam in the heart,
a clutch rocker carrying the transmission mobile, and
a column wheel intended to cooperate with the hammer, the brake and the clutch rocker, to actuate them according to different modes of START, STOP, RESET operation of the chronograph mechanism. According to a preferred embodiment of the invention, the hammer, the clutch rocker and the column wheel are shaped and arranged in such a way that, when the START mode is engaged, the hammer is lifted from the cam. heart just after the clutch rocker is actuated by the column wheel to place it in its engaged state.

In addition, it can then advantageously be provided that the brake, the clutch rocker and the column wheel are shaped and arranged in such a way that, when the STOP mode is engaged, the brake acts on the wheel of the driven wheel, to maintain its fixed angular position, before the actuation of the clutch rocker by the column wheel to place it in its disengaged state.

The present invention also relates to a watch movement comprising a chronograph mechanism exhibiting the characteristics which have just been exhibited, as well as a timepiece equipped with such a watch movement.

Brief description of the drawings

Other features and advantages of the present invention will appear more clearly on reading the detailed description of a preferred embodiment which follows, made with reference to the accompanying drawings given by way of non-limiting examples and in which:

• la figure 2 représente une vue de face simplifiée du mécanisme de la figure 1, dans un deuxième état de fonctionnement;
• la figure 3 représente une vue de face simplifiée du mécanisme de la figure 1, dans un troisième état de fonctionnement;
• la figure 4 représente une vue en perspective simplifiée d'un premier détail de construction du mécanisme de la figure 1, et
• la figure 5 représente une vue en perspective simplifiée d'un deuxième détail de construction du mécanisme de la figure 1.

- the figure 1 represents a simplified front view of a chronograph mechanism according to a preferred embodiment of the invention, in a first operating state;

• the figure 2 represents a simplified front view of the mechanism of the figure 1 in a second operating state;
• the figure 3 represents a simplified front view of the mechanism of the figure 1 in a third operating state;
• the figure 4 represents a simplified perspective view of a first construction detail of the mechanism of the figure 1 , and
• the figure 5 represents a simplified perspective view of a second construction detail of the mechanism of the figure 1 .

Mode (s) of realization of the invention

The figures 1 , 2 and 3 represent a same view from above of a part of a watch movement 1 comprising a chronograph mechanism according to a preferred embodiment of the present invention, the latter being visible by its bridges side in first, second and third states of respective operation. More specifically, the figure 1 illustrates the chronograph mechanism in its rest state after resetting (RESET operating mode), the figure 2 illustrates this mechanism during the measurement of a time (START mode of operation) and, the figure 3 illustrates this mechanism after stopping the measurement of a time, before resetting its counters (STOP function mode).

The figures 1 , 2 and 3 illustrate, in a simplified manner, the main elements of the chronograph mechanism for driving conventional display elements, namely chronograph seconds hands and chronograph minutes (not visible).

It is obvious that this movement is represented by way of nonlimiting illustration and that the skilled person can implement the object of the present invention by adapting it to a chronograph mechanism of alternative construction without departing from the scope of the present invention. 'invention. In particular, it will be noted that the general structure of this chronograph mechanism is here close to that mentioned above in the prior art, to illustrate the fact that the implementation of the present invention requires only a few modifications to existing mechanisms, without calling into question the important progress it represents.

This movement 1 comprises frame elements including a bridge 2, on which are mounted mobiles, levers, latches and other clock components, of which only those related to the chronograph mechanism are illustrated and will be described in detail in this presentation . These components could be mounted on a plate, alternatively, without departing from the scope of the invention.

The chronograph mechanism includes chronograph counters 10 (or chronograph seconds counter) and minutes 20.

Each of these counters comprises a mobile (whose wheel 11, 21 is visible) intended to be driven in connection with a time base (that of the finishing train or a time base specific to the chronograph) and is arranged to drive in rotation a measured time display member (not shown). In addition, in this embodiment, the mobile minute counter 20 also includes a second wheel 23 which is frictionally mounted on the shaft of this mobile, the role of which will be explained below.

Each counter also comprises a core cam 12, 22, each cam being integral in rotation with the corresponding display member and intended to cooperate with a suitable surface of a corresponding reset hammer 14, 24.

The chronograph mechanism illustrated here by way of non-limiting example is of the type comprising a column wheel 30. The latter can be rotated on itself by a hook 32, integral with a control 34 whose pivoting can be controlled, conventionally, from a pusher 35.

More precisely, the chronograph mechanism illustrated and described in this example is of the three-stroke single-pusher type, in other words a complete operating cycle corresponds to three steps of the column wheel 30. In fact, each pressure on the pusher 35 causes a rotation of one step of the column wheel 30, successively passing the chronograph function from a state at rest (RESET mode) to a measurement state of a time (START mode), the state of measurement of a time (START mode) to a stopped state (STOP mode) or from the stopped state (STOP mode) to the idle state (RESET mode). For this purpose, the alternation of solids (columns) and empty acts on different latches to activate or deactivate functions relating to the measurement of time intervals.

The column wheel cooperates in particular with a clutch rocker 36, carrying a clutch mobile 38 and pivotally mounted on the frame between a first position, resting or disengaged, and a second position, driving or engaged. The clutch rocker 36 is arranged here to establish or interrupt a kinematic connection in the chronograph wheel, and to allow the driving of driven mobiles, here the chronograph counters 10 and 20, from a finishing train (no represented), by means of a mobile moving, here a wheel of seconds 40 commonly called wheel over fields with respect to the counter 10, and by either a center mobile (not visible) or the chronograph wheel 11 for Regarding the counter 20. In this sense, the clutch mobile acts as a transmission mobile between the mobile and at least one driven mobile. The driving mobile is here driven by a drive wheel (not visible), itself driven from a power source of the watch movement, possibly via a finishing train.

As described below, the mobile minute counter 20 is, in this embodiment, driven by the center mobile (or minutes) of the watch movement, via an intermediate mobile 42 which meshes permanently with the wheel 23 of the 20. In a variant (described later, in connection with the illustration of the figure 5 ) the minute counter 20 can be instead driven, still via an intermediate mobile 142, from the seconds counter 10 when the latter is engaged with the clutch mobile 38. According to this variant, it is the mobile 142 and not the mobile 20 which comprises a wheel frictionally mounted on the shaft of the mobile.

The column wheel 30 also cooperates with brakes 44 and 46 whose function is, typically, to maintain fixed the angular position, respectively, of the chronograph wheel 11 and the wheel of the minute counter 21, when the measurement of a time is interrupted before resetting.

Furthermore, the column wheel 30 is arranged to cooperate with the reset reset hammer 14, while the latter cooperates itself with the reset hammer minutes 24 via a first nozzle 48, so that both hammers are synchronized. Indeed, the seconds hammer 14 comprises a second spout 50 cooperating or not with the columns of the column wheel 30 to define the angular position of the hammer. The hammers are capable of moving, in a conventional manner, between a rest position, in which each of them bears against the core cam with which it is associated, and a raised position, in which each of them is remote from the core cam with which it is associated to let the corresponding wheel 11, 21 free to turn and measure a time.

Various springs 52, 54, 56, 58, 60, 62 and 64 have also been shown in non-limiting manner, these acting respectively on the control 34, on the reset hammers of the seconds 14 and minutes 24, on the brakes seconds 44 and minutes 46, the clutch rocker 36 and the column wheel 30, to set default positions, in a known manner.

The figure 1 illustrates the watch movement while the chronograph mechanism is in its idle state (RESET mode). In this state, the hammers 14 and 24 are positioned in abutment against the core cams 12, 22 to keep the display members of the measured times immobile, in their position corresponding to the measurement of a zero time.

At the same time, the brakes 44 and 46 are here preferably positioned at a distance from the wheels 11 and 21. The brakes could also be positioned in abutment against the wheels 11 and 21, in this state, without departing from the scope of this invention.

The clutch lever 36 is positioned in its disengaged position, bearing on a column of the column wheel 30, in such a way that the kinematic connection between the field wheel 40 and the chronograph wheel 11 is not established, the clutch mobile 38 not meshing with the chronograph wheel 11 in this configuration. In this embodiment, the friction wheel 23 of the mobile minute counter 20 meshes permanently with a wheel of the intermediate mobile 42, while the other wheel of the intermediate mobile 42 meshes with the mobile center of the watch movement. Since the hammer 24 acting against the core 22 keeps the wheel 21 of the minute counter 20 at the zero position, there is a disengagement between the wheels 21 and 23 thanks to the friction of the wheel 23, and the wheel 21 remains stationary.

Pressing on the pusher 35 rotates the column wheel 30 by one step, via the control 34, to position it in its configuration shown in FIG. figure 2 , corresponding to the measurement of a time (START mode).

When the column wheel 30 rotates, it actuates the clutch rocker 36 and the hammers 14, 24. In particular, the column on which the clutch rocker 36 was resting support shifts and drops the rocker clutch in the vacuum located between it and the next column, under the action of the spring 62, to place the clutch rocker in its engaged state.

The clutch mobile 38 then enters into engagement with the chronograph wheel 11.

The hammers 14 and 24 are raised, just after the fall of the rocker, by a column of the column wheel 30, to release the chronograph counters wheels seconds 11 and minutes 21.

The brakes 44 and 46 remain in their support on the same columns as in the rest configuration to stay away from the chronograph wheels 11 and 21.

During measurement, the clutch mobile 38 acts as a transmission mobile between the field wheel 40 and the chronograph wheel 11. No longer being blocked by the hammer 24, acting against the heart 22, the wheel minutes of chronograph 21 engages with the wheel 23 so that the wheel 21 is driven by the mobile center of the watch movement, through the mobile 42 also fulfilling the role of a mobile transmission.

Pressing the pusher 35 again rotates the column wheel 30 one step, via the control 34, to position it in its configuration shown in FIG. figure 3 , corresponding to the interruption of the measurement of a time (STOP mode).

When the column wheel 30 rotates, a new column raises the clutch lever 36 which interrupts the kinematic connection between the clutch mobile 38 and the chronograph wheel 11, in its disengaged state.

The hammer 14 remains resting on the same column as in the previous phase, while the brakes 44 and 46 are released, before the rise of the rocker 36, by shifting the columns on which they had previously rested, and can fall on the chronograph wheels of seconds 11 and minutes 21 to lock in their respective positions, under the effect of the action of their respective springs 58 and 60.

Pressing the pusher 35 again turns the column wheel one step further to return to the configuration illustrated in FIG. figure 1 (RESET mode).

The figure 4 illustrates a simplified perspective view of a first construction detail of the chronograph wheel which has just been described.

More specifically, the figure 4 illustrates more clearly the mode of cooperation between the leading, transmission and driven mobiles, that is to say between the field wheel 40, the clutch mobile 38 and the chronograph wheel 11.

It appears from figure 4 that the clutch mobile, or transmission, comprises a first wheel 68 arranged in permanent engagement with the field wheel 40, in a conventional manner.

The present invention provides the arrangement of a wheel frictionally mounted on its shaft in the chronograph wheel. This wheel is here a second wheel 70 frictionally mounted on the shaft 72 of the clutch mobile 38. A bridge 73 is integral with the clutch rocker 36 to ensure pivotal mounting of the shaft 72.

When the clutch rocker 36 falls between two columns of the column wheel 30, to move from its position illustrated on the figure 1 to that illustrated on the figure 2 (Engaging the START mode), the first wheel 68 rolls on the field wheel 40, driving the shaft 72 and the second wheel 70 in rotation in the same direction.

The toothing of the second wheel 70 then engages in the toothing of the chronograph wheel 11 with a combined movement of translation and rotation.

The clutch rocker 36, the hammers 14, 24 and the columns of the column wheel 30 are preferably shaped and arranged in such a way that the hammers 14, 24 are still bearing against the core cams 12, 22 at the moment when the toothing of the second wheel 70 engages in the toothing of the chronograph wheel 11.

Thus, when the teeth of the second wheel 70 and the chronograph wheel 11 are not aligned with each other, which causes the jump of the needle in the mechanisms of the prior art as mentioned above. high, the second wheel 70 slides here on its shaft 72, thanks to its frictional assembly, to align its toothing with that of the wheel 11, under the effect of the action of the spring 62 pushing the clutch lever 36 into position. direction of the wheel 11. This movement does not involve needle jumping here because the wheel 11 is blocked by its reset hammer 14.

The shapes of the spout 50 and columns of the column wheel 30 are adapted to ensure a lifting of the hammer 14 of the cam 12 as soon as the toothing of the second wheel 70 is engaged in that of the wheel 11. The measurement of a time can then start.

The assembly of the second wheel 70 on the shaft 72 can be made in any known manner and adapted and the skilled person will not encounter any particular difficulty to implement it. As a non-limiting illustrative example, the skilled person can draw inspiration from the teaching of the patent CH 701075 B1 to achieve this assembly.

Alternatively, it is possible to provide that the clutch mobile has only one wheel 68, the second wheel 70 being in this case frictionally assembled on the shaft of the chronograph mobile 10 being arranged to mesh with the In this case, the second wheel 70 would slide on the shaft of the mobile 10 during the fall of the clutch lever 36, while the chronograph wheel 11 would be blocked by the hammer 14, to avoid a jump of the corresponding needle.

Mention may also be made of the possibility of assembling the second friction wheel 70 on the driving mobile, that is to say on the shaft integral with the field wheel 40, without departing from the scope of the present invention. In this case, the wheel field 40 would be driven by the watch movement but it is the second wheel 70 which would be arranged in permanent engagement with the single wheel 68 of the clutch mobile 38, or alternatively with the drive wheel .

The figure 5 illustrates an example of an alternative construction of the chronograph wheel of Figures 1 to 3 , allowing to highlight an alternative approach to ensure the training of the minute counter. According to this variant, the minute counter 20 no longer has a friction wheel and the entire mobile is driven, via an intermediate mobile 142, from the seconds counter 10 when the latter is engaged with the clutch mobile 38 .

Depending on the angular positions of the wheels 11 and 21 being measured a time, it is possible that these two wheels are rotated in opposite directions during the reset by the hammers 14, 24.

According to this variant, the method of driving the minute counter 20 from the seconds counter 10 via a finger can be replaced by a gear, including a wheel fitted with friction on its shaft and having a better accuracy. Operating.

Indeed, it appears from figure 5 that the intermediate mobile 142 comprises first and second wheels 74 and 76, the first 74 is integral with the shaft 78 of the mobile 142, while the second 76 is frictionally mounted on the shaft 78.

The first wheel 74 is here arranged in permanent engagement with a reference 80 secured to the shaft 82 of the mobile counter seconds 10.

So, in the variant of the figure 5 during the measurement of a time, the movement of the second mobile 10 is transmitted to the mobile of minutes 20 by the intermediate mobile 142, which makes it possible to obtain a display trailing timed minutes, in contrast to jumping retractable finger mechanisms.

During a resetting operation, the second wheel 76 begins to slide on its shaft 78 as soon as the seconds and minutes mobiles 20 are driven in a non-synchronized way by their respective hammers.

In this case, the moving mobile is the mobile seconds chronograph 10 whose movements are transmitted to the mobile minutes of chronographs 20, playing the role of mobile led through the intermediate mobile 142 acting as a mobile transmission .

Of course, a person skilled in the art will be able to choose whether the wheel frictionally mounted on the shaft of the intermediate mobile 142 is that which meshes with the mobile of the seconds 10 or that which meshes with the mobile of the minutes 20 without departing from the scope of the 'invention. Alternatively, it is also possible to provide that the wheels 74 and 76 are both integral with the axis 78 but that the wheel frictionally mounted on its shaft is the return 80 of the mobile seconds 10.

Thanks to the construction which has just been described, in particular by the implantation of a wheel frictionally mounted on its shaft in a judicious location, it appears how a construction chronograph mechanism close to known constructions can be realized, while avoiding some operating problems like jumping the needle at startup.

It will also be noted, in general, that the wheels of the chronograph train according to the present invention may advantageously each have a toothing having an NIHS tooth profile 20-25 or other warhead gear with good transmission efficiency. This profile, conventional in the workings other than those of the chronograph mechanisms, ensures better performance than the triangular profiles generally used in particular between the clutch wheel and the wheel of the mobile seconds chronograph. In addition, the use of such a tooth profile makes it possible to avoid the needling of the needle display of the measured time seconds without having to use the conventional friction spring. Preferably, the wheel frictionally mounted on its shaft and the wheel with which it cooperates each have a micro-module toothing, while the other wheels preferably each have a small module toothing.

The foregoing description attempts to describe a particular embodiment by way of non-limiting illustration and the invention is not limited to the implementation of certain particular features which have just been described, for example the number of mobiles that the chronograph gear train or the implantations illustrated and described for the wheel frictionally mounted on its shaft.

The skilled person will not encounter any particular difficulty in adapting the content of the present disclosure to his own needs and implementing a chronograph wheel having at least one wheel frictionally mounted on one of the shafts of the gear train, without leaving of the scope of the present invention. In particular, it will be noted that several friction wheels can be combined in the same part of the gear train without departing from the scope of the invention, or that a single friction wheel can be used, such as that of the clutch mobile , without necessarily implementing the intermediate mobile 42 or 142.

Claims (14)

Chronograph mechanism, for a watch movement (1), comprising a driving mobile capable of being rotated by a driving wheel for driving on demand a driven wheel (10, 20) via a transmission wheel (38, 42, 142), said driving wheel being itself intended to be driven from a power source of the watch movement, said driven wheel (10, 20) being intended controlling the movements of a display member, each of said drive, driving, transmission (38, 42, 142) and driven (10, 20) having a shaft (72, 78, 82) secured to a first wheel (11, 40, 68, 74),
characterized in that at least one of said driving, transmitting (38, 42, 142) and driven (10, 20) driving wheels comprises a second wheel (70, 76) frictionally mounted on the shaft (72, 78). ) corresponding and arranged to cooperate with said first wheel (11, 21) of another mobile (10, 20) among said driving, driving, transmission (38, 42, 142) and driven (10.20) mobiles . Mechanism according to claim 1, characterized in that said second wheel (70) is frictionally mounted on the shaft (72) of said moving transmission part (38) and is arranged to cooperate with the first wheel (11) of said driven movable ( 10) while the first wheel (68) of said transmission wheel (38) is arranged to cooperate with the first wheel (40) of said mobile driving. Mechanism according to claim 2, characterized in that the first wheel (40) of said driving mobile is a wheel on fields while the first wheel (11) of said driven mobile (10) is a chronograph seconds wheel, and in that said transmission wheel (38) is a clutch mobile carried by a clutch rocker (36) intended to be arranged on the watch movement (1) being able to move between first and second positions, respectively associated with states engaged and disengaged between said second wheel (70) of said transmission wheel (38) and the first wheel (11) of said driven wheel (10). Mechanism according to claim 1, characterized in that said second wheel is frictionally mounted on the shaft (82) of said driven wheel (10) and is arranged to cooperate with the first wheel (68) of said transmission wheel (38) while the first wheel (11) of said driven wheel (10) is intended to control the movements of a display member. Mechanism according to claim 4, characterized in that the first wheel (40) of said driving mobile is a wheel on fields while the first wheel (11) led from said mobile (10) is a wheel of the chronograph seconds, and in that said transmission wheel (38) is a clutch mobile carried by a clutch rocker (36) intended to be arranged on the watch movement (1) being able to move between first and second positions, respectively associated with states engaged and disengaged between the first wheel (68) of said transmission wheel (38) and said second wheel of said driven wheel (10). Mechanism according to claim 1, characterized in that said moving mobile is a mobile (10) chronograph seconds while said mobile is a moving mobile (20) chronograph minutes, said mobile transmission comprising an intermediate mobile (142) comprising a shaft (78) for pivotal mounting on the watch movement (1) and carrying a frictionally mounted wheel (76). Mechanism according to one of the preceding claims, characterized in that said first and second wheels (11, 40, 68, 70, 76) each have a toothing having an NIHS tooth profile 20-25 or a warhead type toothing. Mechanism according to claim 7, characterized in that said second wheel (70, 76) and the first wheel (11, 21) with which it cooperates each have a micro-module toothing. Mechanism according to claim 8, characterized in that said first wheels associated with wheels other than said second wheel each have a small modulus toothing. Mechanism according to one of Claims 1 to 9, comprising
a core cam (12) intended to be integral in rotation with the display member,
a reset hammer (14) having a surface adapted to cooperate with the core cam (12),
a brake (44) for, in the operating position, maintaining fixed the angular position of a wheel of said driven wheel (11) integral with the core cam (12),
a clutch rocker (36) carrying the transmission wheel (38), and a column wheel (30) for cooperating with said hammer (14), said brake (44) and said clutch rocker (36), to operate them according to different operating modes START, STOP, RESET of the chronograph mechanism,
characterized in that the hammer (14), the clutch rocker (36) and the column wheel (30) are shaped and arranged in such a way that, when the START mode is engaged, the hammer (14) is raises the core cam (12) just after the clutch lever (36) is actuated by the column wheel (30) to place it in its engaged state. Mechanism according to claim 10, characterized in that the brake (44), the clutch rocker (36) and the column wheel (30) are shaped and arranged in such a way that when the STOP mode is switched on, the brake (44) acts on said wheel of the driven wheel (11), to maintain its fixed angular position, before actuation of the clutch rocker (36) by the column wheel (30) to place it in its state disengaged. Watch movement (1) comprising a chronograph mechanism according to one of claims 1 to 11. Horological movement (1) according to claim 12, comprising a going train comprising a movable center driven in rotation from a power source of the timepiece movement (1), characterized in that said movable center fulfills the role said mobile driving while said driven mobile is a mobile (20) minute chronograph, said mobile transmission comprising an intermediate mobile (42) for transmitting the movements of said mobile center said mobile (20) minutes chronograph. Timepiece comprising a chronograph mechanism according to one of claims 12 or 13.

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