CH716684A2 - Split-seconds chronograph mechanism for watch movement. - Google Patents

Abstract

The invention relates to a chronograph mechanism comprising a counting wheel set intended to drive a display member of a first unit of time, a reset device comprising a hammer (40) designed to exert pressure. on a cam (6) for resetting the counting mobile, a fly-back mobile intended to drive an additional display member of the first time unit, and comprising a catching device arranged in such a way that the display members can be driven in synchronism and being superimposed on one another, the adjustment device comprising a feeler (28) arranged to cooperate with an indexing cam carried by the counting mobile, the reset cam (6) and the indexing cam being produced in the form of a single central cam carried by a shaft (4) of the counting mobile.

Description

Technical area

The present invention relates to a chronograph mechanism for a watch movement, comprising a counting mobile, associated with a first unit of a measured time and intended to ensure the training of a display member of the first unit of time, a control device capable of allowing training at the request of the counting mobile, a reset device arranged to act on demand on the counting mobile and positioning it in a predefined angular rest orientation, the device reset comprising a hammer arranged to exert pressure on a reset cam of the counting mobile, a split-second wheel intended to drive an additional display member of the first time unit, and comprising a catching device arranged in such a way that the display members of the first unit of time can be driven in synchronism and being superimposed on each other e, the catching device comprising a feeler arranged to cooperate with an indexing cam carried by the counting mobile.

[0002] The present invention also relates to a watch movement comprising such a watch mechanism as well as a timepiece comprising such a watch movement.

State of the art

[0003] Such display mechanisms are already known from the state of the art, in particular when the first unit of time is the second.

[0004] By way of example, the work entitled "Theory of horology", by C.-A. Reymondin et al., Edited by the Fédération des Ecoles Techniques (Switzerland), ISBN 2-940025-10-X, describes and illustrates a construction of a split-seconds chronograph mechanism meeting the above characteristics, on pages 249 to 251. Typically , the chronograph mechanism is located on the bridge side of the watch movement and the split-seconds mechanism is added on top, to finally be the mechanism located closest to the back of the case of the corresponding watch. Starting from a standard chronograph mechanism, a split-seconds mobile can be added to the watch movement while the shaft of the chronograph seconds mobile is replaced by a tube through which the shaft of the split-seconds mobile is used, intended to carry the corresponding display needle. A catch-up device is also used, this generally comprising a specific split-seconds cam added to the end of the shaft of the chronograph seconds wheel set, while the split-second wheel unit comprises an arm carrying a feeler held in position. support against the split-seconds cam under the effect of the action of an elastic member. Thus, when the split-seconds mobile is free to turn, it occupies a predefined relative position with reference to the chronograph seconds mobile, generally such that the two corresponding hands are superimposed. Furthermore, the mechanism comprises a device for locking the split-seconds mobile designed to be able to lock the latter on demand and immobilize the corresponding display hand, in order to read an intermediate time. When the split-second mobile is released, the split-second hand catches up with the chronograph seconds hand, under the effect of the action of the catching device, in such a way that the two hands are again superimposed.

Split-seconds function chronograph mechanisms are not widely used because of their complexity, particularly in terms of assembly and adjustments. Thus, these mechanisms have only been subject to a limited number of modifications and developments over time.

[0006] Patent application CH 682201G A3 describes an alternative construction to that described above, making it possible to add a split-seconds function to a standard watch movement already comprising a chronograph mechanism. To this end, all the components relating to the split-seconds mechanism are located on the base movement on its dial side rather than on the bridges side as is generally the case.

Overall, all the known constructions are relatively complex and the need still exists to develop solutions which make it possible to simplify them.

Disclosure of the invention

A main aim of the present invention is to provide an alternative construction to the constructions already known for producing a chronograph mechanism incorporating a split-seconds mobile, making it possible to simplify its production with reference to known constructions.

To this end, the present invention relates more particularly to a chronograph mechanism of the type mentioned above, characterized in that the reset cam and the indexing cam are produced in the form of a single and same central cam carried by a shaft of the counting mobile.

[0010] Thanks to these characteristics, the construction is simplified since it comprises fewer components than the previous constructions, and in addition it has a lower thickness due to the use of a single core instead of the two conventional cores.

Preferably, one can provide that the take-up device comprises a board on which an arm carrying the probe is rotatably mounted, as well as an elastic member exerting a force on the arm tending to position the probe resting against the central cam.

[0012] In this case, the arm can advantageously carry a guide member arranged to cooperate with the board of the take-up device and ensure guiding of the feeler in a guiding direction substantially parallel to the direction of the shaft of the counting mobile. . In particular, provision can be made for the guide member to comprise first and second guide fingers respectively arranged on either side of the board in the direction of guidance.

Advantageously, provision can be made for the fly-back mobile to be arranged, with reference to the counting mobile, such that its board is adjacent to the central cam in the direction of the shaft of the counting mobile. Thus, the catching device making it possible to ensure the indexing between the counting and fly-back mobile units can be produced in a relatively compact manner.

According to a first variant embodiment, provision can be made for the board to be located on the dial side with reference to the central cam, the split-seconds mobile comprising a tube, intended to carry a split-seconds hand of the first unit of time and, through which is arranged the shaft of the counting mobile, the latter being intended to carry a display hand of the first unit of time.

According to an alternative embodiment, provision can be made for the board to be located on the bridge side with reference to the central cam, the shaft of the counting mobile having the shape of a tube, intended to carry a display needle of the first time unit and, through which is arranged a split-second mobile shaft, the latter being intended to carry a split-second hand of the first time unit.

In general, provision can be made for the first unit of time to be the second.

Furthermore, one can also provide, in general, that the chronograph mechanism according to the invention has the form of an independent module capable of being assembled to a basic watch caliber, preferably to a plate of this last, so that a kinematic link is established to ensure the operation of the control device.

The present invention also relates to a watch movement comprising a chronograph mechanism meeting the characteristics which have just been stated.

Provision can be made for the central cam to be arranged on the dial side of the plate of the watch movement, or on the bridges side, even though the arrangement on the dial side may have greater appeal for the wearer of the corresponding watch if the latter does not have a dial or a transparent dial allowing the mechanism to be viewed.

In general, the present invention also relates to a timepiece comprising a watch movement meeting the characteristics stated above.

Brief description of the drawings

Other characteristics and advantages of the present invention will emerge 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 example and in which : FIGS. 1, 2 and 3 represent simplified views, respectively in perspective, from above and from the side, of part of a chronograph mechanism according to a preferred embodiment of the present invention, and Figure 4 shows a simplified cross-sectional view of part of the chronograph mechanism according to the preferred embodiment of Figures 1 to 3.

Mode (s) for carrying out the invention

Figures 1, 2 and 3 show part of the same chronograph mechanism 1 according to a preferred embodiment of the present invention, according to three different respective views, more precisely in perspective, in top view and in view next to.

The chronograph mechanism 1 according to the present invention can be directly integrated into a watch movement or it can be assembled with a basic watch movement in the form of an additional module without departing from the scope of the invention.

The chronograph mechanism 1 comprises in particular a counter for the seconds of measured time, or a mobile for counting the seconds, comprising a chronograph seconds wheel 2. The seconds wheel 2 can be driven in any known and suitable manner, and a person skilled in the art will not encounter any particular difficulty in implementing a drive mechanism allowing it to be driven according to his own needs. and constraints.

[0025] Thus, the construction details of the basic watch movement and of the mechanism for driving the seconds wheel 2 will not be discussed here, for the sake of brevity and simplification, given that the implementation of the present invention does not depend directly on it.

The main characteristics of the chronograph mechanism 1 will now be presented with the aid of FIGS. 1 to 3 which illustrate a preferred embodiment thereof in three different views making it possible to better visualize all the aspects which will be treated.

Conventionally, in addition to the seconds wheel 2, the seconds counting mobile comprises a shaft 4, integral with the seconds wheel 2, a reset cam 6, integral with the shaft 4, as well as a finger 8 for driving a minute counter of the measured times, not shown.

The shaft 4 is typically intended to carry a chronograph seconds display hand (not illustrated).

The finger 8 is produced here, by way of non-limiting illustration, in the form of an elastic finger made in one piece with a transmission wheel 10 integral with the shaft 4. In known manner, the finger 8 is intended to cooperate at each revolution of the seconds counter with a minute counter to advance it by one step. The driving of the minute counter is typically possible in only one direction, the finger 8 retracting elastically in the opposite direction.

It will be noted that the transmission wheel 10 has a hole 12 intended to facilitate the gripping thereof during the indexing of the finger 8 with reference to the shaft 4 and therefore, more precisely, to the reset cam 6 which defines the position of the shaft 4 associated with a zero measured time, or also the corresponding position of the chronograph seconds display hand.

Of course, the chronograph mechanism 1 is intended to be associated with a control device making it possible to drive and stop at the request of the counting mobile, in particular of the seconds wheel 2, as well as to a reset device intended to act on demand on the counting mobile (s) and position (s) according to respective angular orientations of predefined rest.

According to the present invention, the chronograph mechanism 1 also comprises a split-seconds mobile 20 intended to drive a display member of the additional measured time seconds (not shown), typically a split-seconds hand seconds, and comprising a catching device arranged in such a way that the chronograph and split-second seconds display hands can be driven in synchronism and being superimposed on one another.

The split-second mobile 20 comprises a split-second board 22 integral with a split-second shaft 26 intended to carry the split-second needle.

The catching device comprises a feeler 28 arranged to cooperate with an indexing cam carried by the mobile for counting the seconds of the measured times. For this purpose, the feeler 28 is carried by an arm 30 rotatably mounted on the flyback board 22, being subjected to the permanent action of a spring 32 carried by the flyback board 22 tending to push the arm 30 in the direction from the center of the second counting mobile. The spring 32 is here produced in one piece with the split-second board 22 without limitation.

It appears more clearly from Figure 3 that the indexing cam with which the probe 28 cooperates is here the reset cam 6 of the second counting mobile, in accordance with the basic principle of the present invention. Thus, instead of using two different cams spaced apart from one another on the chronograph seconds mobile, as is usually the case, the present invention proposes to use only one and the same. cam to perform the two functions concerned, namely, on the one hand, the resetting of the chronograph seconds counter, and, on the other hand, the indexing of the split-seconds mobile on the chronograph seconds counter.

Thanks to this characteristic, not only the thickness of the mechanism is reduced with reference to the previous mechanisms, but also the number of components is also reduced and the assembly of the mechanism is simplified.

Note that the feeler 28 is produced here in a particular form, that is to say in the form of a cylindrical roller rotatably mounted on a tenon 34 assembled to the arm 30.

Furthermore, it will also be noted that according to the preferred embodiment illustrated in the figures, by way of non-limiting illustration, the split-seconds mobile is located on the dial side of the chronograph seconds mobile. Thus, the fly-back shaft 26 is hollow to define a passage for the shaft 4 of the chronograph seconds counter. In such a configuration, the chronograph seconds hand will be located above the split-seconds hand, whereas a reverse configuration is more generally found.

Of course, the reverse configuration can also be envisaged without departing from the scope of the present invention, that is to say that the split-seconds mobile can be arranged on the bridge side of the chronograph seconds mobile. In this case, it is the shaft of the chronograph seconds mobile which should be hollow to define a passage for the split-seconds shaft, while the split-seconds hand would be located above the seconds hand. chronograph.

The construction characteristics according to the present invention can give rise to specific constraints to be taken into account, in particular according to the thickness of the reset cam 6. In fact, the thinner this cam is, the more l The space available between the seconds wheel 2 and the board 22 of the split-second mobile is limited. However, this space must remain sufficient to allow the simultaneous passages of the feeler 28 and of a hammer 40 for resetting the counter of the seconds of time measured, as illustrated in FIG. 4.

Figure 4 illustrates part of the chronograph mechanism 1 in a cross-sectional view passing through the shafts 4 and 26 as well as through the feeler 28.

It appears that split-second pliers 42 are furthermore arranged at least partially in the same plane as the split-second board 22, to cooperate with the latter at the request of the user, when he wishes to read an intermediate time by blocking the rattrapante needle.

The chronograph mechanism 1 shown in Figure 4 is of the modular type, in a nonlimiting manner, being assembled between a plate 44 of additional module and bridges, including a chronograph bridge 46 visible in the center. A tube 48 is assembled to the chronograph bridge 46 to ensure guidance not only of the split-seconds shaft 26 but also, on the outside, of a roadway and an hour wheel (not visible) for display. of the current time.

FIG. 4 more particularly illustrates one configuration among other possible ones, in which the feeler 28 and the hammer 40 are superimposed, which makes it possible to illustrate the impact of the thickness of the reset cam 6 on the construction of the mechanism in terms of vertical flats (in a direction parallel to the direction of the shafts 4 and 26), in particular precisely between the feeler 28 and the hammer 40.

The Applicant has developed means making it possible to secure the construction, in particular in the event of impact, more clearly visible in FIGS. 1 to 3.

These securing means comprise a guide member comprising first and second guide fingers 50, 52 arranged to cooperate with the split-second board 22 and ensure guidance of the feeler 28 in a guiding direction substantially parallel to the direction of the shafts 4 and 26. For this purpose, the guide fingers 50, 52 are arranged on either side of the fly-back board 22, facing a portion 54 of the board having an internal periphery of slightly modified shape for be able to cooperate with the guide fingers 50, 52 regardless of the position of the probe 28.

Thus, in the event of an impact, for example, the fingers 50, 52 are capable of defining stops, in relation to the portion 54 of the board 22, to limit the amplitude of the movements of the arm 30 in the direction of the 'thickness of the mechanism.

The foregoing description attempts to describe a particular embodiment by way of nonlimiting illustration and, the invention is not limited to the implementation of certain particular characteristics which have just been described, such as for example the nature of the magnitude displayed by the display members are intended to display or the shape and the manner in which certain components are produced when they can be modified without impact on the implementation of the present invention , such as for example the shape of the feeler 28, of the arm 30, of the spring 32 or of the finger 8 for driving the minute counter when the main counting wheel set is intended to count the seconds of measured time. It is also conceivable to produce a movement which would include two split-seconds according to the invention, in particular one for the seconds and one for the minutes, without departing from the scope of the invention.

The exemplary embodiment which has been described allows those skilled in the art to produce a counting mechanism of limited space, in particular according to the direction of the thickness of the mechanism, comprising a main display member as well that an associated split-seconds member, capable of presenting some adaptations according to its own needs without departing from the scope of the present invention.

Claims (11)

1. Chronograph mechanism (1) for a watch movement, comprising a counting mobile, associated with a first unit of a measured time and intended to ensure the driving of a display member of said first unit of time, a control device capable of allowing training at the request of said counting mobile, a reset device arranged to act on demand on said counting mobile and position it in a predefined angular rest orientation, said reset device comprising a hammer (40) designed to exert pressure on a cam (6 ) resetting said mobile counting device to zero, a fly-back mobile (20) intended to ensure the driving of an additional display member of said first unit of time, and comprising a catch-up device arranged in such a way that said display members of said first unit of time can be driven in synchronism and being superimposed on one another, said catching device comprising a feeler (28) arranged to cooperate with an indexing cam carried by said counting wheel set, characterized in that said reset cam (6) and said indexing cam are produced in the form of one and the same central cam carried by a shaft (4) of said counting wheel set. 2. Mechanism (1) according to claim 1, characterized in that said take-up device comprises a board (22) on which an arm (30) carrying said feeler (28) is rotatably mounted, as well as an elastic member (32 ) exerting a force on said arm (30) tending to position said probe (28) in abutment against said central cam. 3. Mechanism (1) according to claim 2, characterized in that said arm (30) carries a guide member arranged to cooperate with said board (22) and ensure guidance of said sensor (28) in a substantially parallel guiding direction. in the direction of said shaft (4) of said counting mobile. 4. Mechanism (1) according to claim 3, characterized in that said guide member comprises first and second guide fingers (50, 52) respectively arranged on either side of said board (22) in said direction of guidance. 5. Mechanism (1) according to one of claims 2 to 4, characterized in that said split-seconds mobile (20) is arranged, with reference to said counting mobile, such that said board (22) is adjacent to said central cam in the direction of the shaft (4) of said counting mobile. 6. Mechanism according to claim 5, characterized in that said plate (22) is located on the dial side with reference to said central cam, said fly-back mobile (20) comprising a hollow shaft (26) intended to carry a fly-back needle. said first unit of time and through which is arranged said shaft (4) of said counting mobile, the latter being intended to carry a display hand of said first unit of time. 7. Mechanism (1) according to claim 5, characterized in that said board is located on the bridge side with reference to said central cam, said shaft of said counting mobile having the shape of a tube intended to carry a display needle of said first unit of time and through which is arranged a shaft of said fly-back wheel set, the latter being intended to carry a fly-back hand of said first unit of time. 8. Mechanism (1) according to one of the preceding claims, characterized in that said first unit of time is the second. 9. Mechanism (1) according to one of the preceding claims, characterized in that it has the form of an independent module capable of being assembled to a basic watchmaking caliber, preferably to a plate of the latter, of such so that a kinematic link is established to ensure the operation of said control device. 10. Watch movement comprising a chronograph mechanism (1) according to one of claims 1 to 9. 11. Timepiece comprising a horological movement according to claim 10.