Timepiece comprising a chronograph mechanism

A timepiece with a movement that includes: a power source; an element for displaying the current time; a chronograph mechanism including a control mobile (60) including at least one control member for activating the start, stop and reset functions of the chronograph. The control mobile (60) further includes a driving member having a toothed sector (84) kinematically connected to the control member. The timepiece further includes a button that can be rotated, the button being rigidly connected by teeth that can be kinematically connected to the toothed sector so that the pivoting of the button activates the start, stop and reset functions of the chronograph.

TECHNICAL FIELD

The present invention relates to the field of mechanical horology. It more particularly concerns a timepiece comprising a movement equipped with:a power source,means for displaying the current time, anda chronograph mechanism comprising a control mobile including at least one control member to activate the start, stop and reset functions of the chronograph.

BACKGROUND OF THE INVENTION

Chronograph mechanisms are varied and are well known by those skilled in the art. There are two main types, depending on whether the control mobile is a column wheel or a cam. One can in particular refer to the work “Théorie de l'horlogerie” by Reymondin et al, Fédération des Ecoles Techniques, 1998, ISBN 2-940025-10-X, pages 225 to 252, to find details on these mechanisms.

Conventionally, the functions of the chronograph mechanism are activated using two push-pieces, acting on the control mobile, at a driving member. In chronographs with column wheels, the driving member is a toothed plate. In a cam chronograph, there are two shuttles that make up the cam. The shuttles form both the control member and the driving member. Indeed, one of the push-pieces acts on one of the shuttles so that its movement activates the start and stop functions, and the other of the push-pieces acts on the other one of the shuttles so that its movement activates the reset function.

Also known are single push-piece chronographs, in which all of the functions are performed, as the name indicates, by a single push-piece. The latter part acts in translation on a column wheel, the control member of which is adapted to control all of the functions. Elegantly, this push-piece is generally housed in a control arbor and protrudes from the crown situated at the end of the arbor. The latter performs, conventionally, the setting and winding functions of the movement, independently of the chronograph. The winding is done in position 0 of the control arbor, i.e. when the latter is in its proximal position relative to the movement, and the setting is done in position 1 of the control arbor, i.e. in a more remote position of the arbor relative to the movement.

It can be noted that in both types of chronograph, bulky levers with sometimes complex forms are inserted between the push-pieces and the driving member of the control member.

The present invention aims to propose a particularly original alternative to activate the functions of a chronograph mechanism and avoiding the aforementioned drawbacks.

BRIEF DESCRIPTION OF THE INVENTION

More precisely, the invention concerns a timepiece as defined in the first paragraph above, characterized in that the control mobile also comprises a driving member including a toothed sector kinematically connected to the control member. The timepiece also comprises a button capable of being driven in rotation, this button being integral with a toothing capable of being kinematically connected to the toothed sector, such that the pivoting of said button activates the start, stop and reset functions of the chronograph.

It can be noted that, advantageously, the proposed construction makes it possible to eliminate the levers between the control arbor and the driving member. In fact, they can be easily adapted to an existing chronograph mechanism.

Other advantageous features are defined in the claims.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows the main elements of a chronograph mechanism according to one preferred embodiment of the invention, the elements being mounted on a frame. This mechanism can be integrated into or mounted modularly on a basic movement which, for the sake of clarity, is not shown. Naturally, this movement comprises a power source to drive a going train and to display the current time using display members. A control arbor8, visible inFIG. 2, also called winding stem, is provided conventionally to be able to occupy a first position in which it is arranged to wind the power source, and a second position in which it is arranged to act on the display means. These two functions are well known by those skilled in the art and can be done by a system including a winding pinion, a castle-wheel and a pull-out piece.

Like a conventional cam chronograph mechanism,10shows an oscillating pinion, driven continuously by a second wheel of the movement. This pinion10is mounted on a lever12ending with a first feeler-spindle14. A spring member16exerts a force on the lever12tending to bring the pinion10into contact with a chronograph wheel18, designed to turn at a rate of one revolution per minute, when the pinion10is coupled.

Typically, the wheel18is provided with60teeth, so as to provide precise coupling to the second. The chronograph wheel18is designed to support a display member for the second of the measured time. A heart-piece20is mounted integral on the axis of the wheel18. Moreover, an elastic finger22is also arranged on the wheel18, to drive once per revolution, an intermediate train24, engaged with a minute counter wheel26. The counter wheel26is designed to support a display member of the minute of the measured time. A heart-piece28is mounted integral on the axis of the wheel26. A jumper spring30ensures the positioning of the wheel26.

A brake-lever32is mounted pivoting on the frame. It includes a brake34designed to cooperate with the chronograph wheel18to block its rotation, and a second feeler-spindle36designed to control the positioning of the brake-lever32, as will be understood later. A spring35is arranged so as to exert a force tending to press the brake34against the chronograph wheel18.

A double-hammer38is provided so as to cooperate with the heart-pieces20and28, to reset the second and minute display members. The double-hammer38is provided with a lever40including a third feeler-spindle42, designed to control the position of the double-hammer38. A yoke44is pivotably mounted on the lever. On either side of the pivot point, the yoke44is provided with first48and second50support surfaces, respectively, to cooperate with the heart-pieces. Two pins52arranged on the lever40are provided to limit the pivoting of the yoke44. A spring54exerts a force on the yoke tending to bring the support surfaces48and50against their respective heart-piece.

A control mobile60is arranged to cooperate with the different feeler-spindles and thus to position the above elements so as to activate the start, stop and reset functions of the chronograph mechanism. According to the embodiment chosen as illustration, the control mobile comprises a control member made up of a cam pivoting around an axis AA. One can, for more clarity, refer toFIGS. 2,3and4, which more particularly show the elements of the cam.

The cam includes a first shuttle62(FIG. 2), called upper. It has an active zone64designed to cooperate with the third feeler-spindle42of the double-hammer38. Depending on the position of the cam, the active zone64is arranged so as to oppose or not oppose the force exerted by the spring54. Respectively, the support surfaces do or do not cooperate with the heart-pieces of the wheels18and26.

The cam includes a second shuttle66(FIG. 3), called intermediate, integral in rotation with the first. It has an active zone78designed to cooperate with the first feeler-spindle14of the yoke12. Depending on the position of the cam, the active zone78is arranged so as to oppose or not oppose the force exerted by the spring member16. Respectively, the pinion10is not coupled or is coupled with the chronograph wheel18. The shuttle66also includes a protruding element, such as a pin80, the role of which will appear later.

The cam also includes a third shuttle76(FIG. 4), called lower. The shuttle76has two hollows70a, separated by a tooth70b, with which a jumper72cooperates, so as to define the two stable positions of the cam corresponding to the start and stop functions of the chronograph. Moreover, one of the hollows, that defining the stop function, extends beyond the level defined by the tooth70b, by an inclined plane70cwith which the jumper72cooperates to position the cam for the reset function of the chronograph. Lastly, the shuttle76has a housing74positioned and dimensioned such that the pin80is positioned there, without play in the direction of rotation of the cam. The shuttle76also has an active zone68designed to cooperate with the second feeler-spindle36of the brake-lever32. Depending on the position of the cam, the active zone68is arranged so as to oppose or not oppose the force exerted by the spring35. Respectively, the brake34does not cooperate or cooperates with the chronograph wheel18.

An additional spring82is positioned so as to act on one of the shuttles, preferably on the third shuttle76, when the reset function is activated, so that it is harder for the user to activate.

According to one important aspect of the invention, the shuttle76extends in a toothed sector84, concentric to the axis AA. One therefore understands that by acting on the toothed sector84, one will drive the pivoting of the lower cam and, with it, via the cooperation between the pin80and the walls of the housing74, the pivoting of the shuttles66and62. One will note that the pin80and the housing74could be reversed, the pin80being on the shuttle76and the housing being on the shuttle66.

To act on the toothed sector, the timepiece according to the invention proposes using the control stem8of the movement. Other than the winding pinion and the castle-wheel, the stem8supports an additional pinion86, integral in rotation and designed to mesh with the toothed sector84, in a predetermined position of the stem8. As shown inFIG. 5, the pinion86and the toothed sector84mesh at 90°. One therefore sees that this construction makes it possible to avoid any arm and intermediate lever between the crown of the winding stem, which serves as actuating member for the chronograph, and the control mobile. There is indeed a direct transmission of the power, by meshing between the pinion86and the sector84. The operation is particularly flexible and precise relative to a mechanism comprising arms and levers between the push-pieces and the control mobile.

To allow comfortable operation of the activation of the chronograph functions, the movement of the toothed sector must be fairly quick, relative to the rotation of the crown. Indeed, for example, the starting of the chronograph must be done after a limited rotation of the crown and not after a complete revolution. In this aim, the diameter of the pinion86is relatively significant, typically in the vicinity of 5 mm. Moreover, according to the construction illustrated in the drawing, the toothed sector84can be situated on the periphery of the movement. The pinion86is then relatively close to the crown, which can make it difficult to mount in the case. To offset this problem, the stem is preferably jointed, essentially at the pinion, between the latter part and the crown. The portion of the stem supporting the pinion86can thus be easily assembled in the movement, while the other portion, designed to support the crown, can be mounted after interlocking, through the outside.

The position of the castle-wheel and the winding pinion can advantageously be adapted such that, in its proximal position, the stem makes it possible to activate the chronograph functions. There is therefore no need to exert any prior traction on the stem to start the chronograph. When the control stem is pulled into a second position, the power source can be wound and, in a third distal position, the setting can be done.

We will now describe the activation of the different functions of the chronograph, in reference toFIGS. 6,7and8.

Idle (FIG. 6), the toothed sector84is essentially symmetrical relative to the axis of the control stem. The cam is kept in that position by the jumper72, which cooperates with a first hollow70a. The first feeler-spindle14of the lever12bears on the active zone78of the shuttle66. The pinion10is uncoupled from the chronograph wheel18. At the second feeler-spindle36of the brake-lever32, the active zone68of the third shuttle76does not oppose the spring35and the brake34cooperates with the wheel18to block it. The third feeler-spindle42of the double-hammer cooperates with the active zone64of the first shuttle62to oppose the spring54. The hammer is raised and the support surfaces do not cooperate with the heart-pieces20and28.

To activate the start function of the chronograph, the crown is pivoted by the wearer in the counterclockwise direction, so as to drive the rotation of the shuttle76in the clockwise direction, in reference toFIG. 7. The rotation of the shuttle76drives the simultaneous pivoting of the shuttles66and62. The jumper72goes into the other hollow70aand thus keeps the cam in that position. The first feeler-spindle14of the lever12no longer bears on the active zone78of the shuttle66, which therefore no longer opposes the spring16. The pinion10is coupled on the chronograph wheel18. The second feeler-spindle36of the brake-lever32bears on the active zone68of the third shuttle76, which opposes the spring35. The brake34no longer cooperates with the wheel18. The hammer is still raised and the support surfaces do not cooperate with the heart-pieces20and28.

Clockwise pivoting of the crown by the wearer causes the counterclockwise rotation of the shuttle76, in reference toFIG. 6. The shuttles66and62also pivot and the jumper72goes back into the first hollow70a. One is then in the idle position previously described, the chronograph is stopped. The wearer can restart and stop the chronograph as desired, without resetting.

To activate the reset, the wearer must, in reference to the idle position, by way of which he must necessarily pass, pivot the crown clockwise, driving the counterclockwise rotation of the shuttle76, in reference toFIG. 8. The shuttles66and62also pivot, stressing the additional spring82, and the jumper72goes up on the inclined flank70c. The first feeler-spindle14of the lever12is still bearing on the active zone78of the shuttle66. The pinion10is uncoupled from the chronograph wheel18. The second feeler-spindle36of the brake-lever32bears on the active zone68of the third shuttle76, which opposes the spring35. The brake34does not cooperate with the wheel18. The third feeler-spindle42of the double-hammer no longer cooperates with the active zone64of the first shuttle62. Under the effect of the spring54, the hammer falls and the support surfaces press the heart-pieces20and28, to reset the display members. When the user releases the crown, the jumper72returns the mechanism to its idle position, through action on the inclined flank70c.

It is therefore the jumper that positions the cam such that the functions can be performed correctly. However, the user could pivot the crown too much, which could cause the shuttles to force on the feeler-spindles. To avoid this, it is possible to have banking elements on the frame, on either side of the shuttle76.

Thus is proposed a chronograph mechanism making it possible to activate the different functions particularly originally, while eliminating any lever between the control stem and the driving member of the control member.

FIGS. 9 and 10propose two other embodiments, also making it possible to actuate the different functions of the chronograph according to a principle similar to that proposed above.

InFIG. 9, we see the toothed sector84ending the third shuttle76. A ring90dimensioned so as to essentially surround the movement is arranged on the casing-ring. More particularly, the inner diameter of the ring90is sufficient for the movement to be able to be positioned there, while its outer diameter allows that ring90to be masked by the casing ring or inside the watch case. The ring90is placed on the casing ring and is guided in rotation, possibly by stones. The ring90is at least partially toothed and comprises a first90aand second90btoothing, on its inner periphery and on its outer periphery, respectively. The toothings can be directly notched in the ring, on the entire periphery or not, or, as in the example shown inFIG. 9, be made by attached pieces, making it possible to arrange the toothings only in the required zones. Such an arrangement can be interesting in terms of bulk.

To actuate the chronograph functions, a button92is mounted in rotation in the case, so as to be accessible from the outside by the wearer of the watch. In the illustrated example, but non-limitingly, the button92can pivot along an axis perpendicular to the plane of the movement. In other words, the button defines a plane essentially parallel to that of the movement. The button92is integral in rotation with a toothing, typically assuming the form of a pinion94arranged coaxially thereto. This pinion94meshes with the ring90, preferably by the second toothing90bsituated at its outer periphery. The toothed sector84is engaged with the first toothing90asituated at the inner periphery of the ring.

Thus, by pivoting the button92, the user can actuate the different functions of the chronograph. One will note that the button92can also be mounted pivoting along an axis parallel to that of the movement, the pinion94meshing perpendicularly with the ring.

InFIG. 10, there is also a toothed sector84ending the third shuttle76. A rack96is mounted mobile in translation inside the case or the movement, being guided by at least one oblong opening, inside which a fixed element cooperates, such as a screw, for example, fixed on a support of the movement or on the case of the movement. A person skilled in the art can use any other means at his disposal to mount the rack. A button92is mounted in rotation in the case, in order to be accessible from the outside. In one advantageous embodiment, the button is mounted on the upper portion of the case, on the dial side, possibly in a corner of said case, in the event of a square case with a round dial. As in the preceding embodiment, the button92can pivot along an axis perpendicular to the plane of the movement and is integral with a pinion94, which is coaxial thereto. The rack96meshes on one hand with the pinion94and on the other hand with the toothed sector84. A person skilled in the art will easily be able to adapt the different levels of these elements such that the rack96can transmit a rotation of the button92to the driving member of the chronograph mechanism. In particular, the toothed sector84normally being situated on the side of the back of the movement, if the button92is situated on the dial side, the pinion94can be connected to the button92by an arbor that passes through the movement. Thus, by pivoting the button, the user can actuate the different functions of the chronograph.

The embodiments ofFIGS. 9 and 10have the same advantages as above, with the additional advantage of releasing the control stem for a third function, in particular for correcting a date or a GMT, for example. In these embodiments, the control stem98no longer has a functional connection with the chronograph mechanism. Moreover, the builder can arrange the control member of the chronograph particularly flexibly, in reference to the button.

The description above was provided as a non-limiting example of the invention. Thus, the control member could also be a column wheel, the toothed sector of the driving member then assuming the form of a wheel. The activation of the different functions will then have to be adapted. Thus, the crown would still have to turn in the same direction to go from one function to the other, the chronograph only being able to function according to the start/stop/reset sequence. Certain details of the embodiments could obviously be adapted by one skilled in the art, in particular at the connection between the shuttles, or in the limitation of the travel of the cam.