Chronograph mechanisms, watch movements and watches

Abstract

To provide a chronograph mechanism including a holding device that holds a chronograph counter display in a fixed position.SOLUTION: A chronograph mechanism 10 includes: a seconds counter 210 forming a first chronograph counter and having a seconds counter display 214; and a second chronograph counter 220 having a second chronograph counter display 224. The chronograph mechanism 10 includes a position-holding device 240 that holds the second chronograph counter display 224 in a fixed position. The position-holding device 240 is configured to ensure that the second chronograph counter display 224 is held in the fixed position only when the second chronograph counter display 224 is in an angular reference position and when the chronograph mechanism 10 is stopped.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a chronograph mechanism including a device for holding the display of a chronograph counter for a timepiece movement in a fixed position, in particular a reference position.

[0002] The invention further relates to a timepiece movement including such a chronograph mechanism.

[0003] The invention further relates to a timepiece including such a timepiece movement. [Background technology]

[0004] The chronograph mechanism allows measuring time on demand by means of several chronograph counters, e.g. a minutes counter and a seconds counter.

[0005] Play in chronograph counter displays is a well-known problem in watchmaking. This play becomes noticeable and problematic after the counters have been reset to zero.

[0006] This play can cause the display to wobble and be visible to the user, especially in the event of a minor shock. This play can also cause the display to move forward of the dial scale, especially relative to a reference position.

[0007] This play in the display is due in particular to the various gears that are accumulated in the gear train between the seconds counter that engages the running train and the various counters of the chronograph set running from the seconds counter.

[0008] In order to avoid this undesirable play in the chronograph display, it is known to use a jumper acting on one of the wheels of the minute counter wheel set, thereby maintaining the stability of each angular position assumed by that wheel of the minute counter wheel set, and since the action of such a jumper is permanent, the stability of the minute counter display is maintained in each position both when the chronograph mechanism is stopped and when it is started.

[0009] Conventionally, the jumper has a beak terminating in two inclined surfaces arranged to rest between the tips of two consecutive teeth of a given wheel of the minute counter wheel set. When a given wheel of the minute counter wheel set is driven by the seconds counter wheel set via a gear train, the teeth of the given wheel of the minute counter wheel set lift the jumper, which then drops between the other two teeth.

[0010] As can be easily understood, such a holding device which holds the minute counter in a fixed position results in a relatively high power consumption with each step through which the minute counter is driven.

[0011] This power consumption causes the speed of the clock movement to change or the amplitude of the regulating member to change. The variations in the speed of the movement or the isochronism of the regulating member are due, at least in part, to the fact that the power consumption during the start of the chronograph mechanism does not remain the same, since power is consumed for every complete revolution of the seconds counter when the minutes counter is driven.

[0012] As a result, there is a need to improve the chronograph mechanism, and in particular the holding device that holds the chronograph counter display in a fixed position. Summary of the Invention

[0013] In this context, the present invention provides a chronograph mechanism for a timepiece movement that meets this need.

[0014] In this context, the invention relates to a chronograph mechanism for a timepiece movement having a chronograph train comprising a seconds counter forming a first chronograph counter, the seconds counter comprising a seconds counter axle carrying a seconds counter display, a seconds counter wheel and a drive finger driving an inter-counter wheel in steps between each revolution of the seconds counter wheel, the second chronograph counter comprising a second chronograph counter axle carrying a second chronograph counter display and a second chronograph counter wheel actuated by the inter-counter wheel.

[0015] The chronograph mechanism further includes a position-maintaining device that holds the second chronograph counter display in a fixed position, and the position-maintaining device is configured to ensure that the second chronograph counter display is held in a fixed position only when the second chronograph counter display is in a predetermined angular reference position and when the chronograph mechanism is stopped.

[0016] Such a position-keeping device according to the invention makes it possible to avoid wobbling and angular play that may be visible to the user on the display of the chronograph counter after resetting, when the chronograph train is no longer engaged with the running train and when the various wheel sets of the chronograph train are no longer engaged with each other.

[0017] In addition to the features mentioned in the previous paragraph, the clock movement according to the invention may have one or more complementary features from among the following, considered on an individual basis or according to any technically possible combination: - Position keeping device a positioning cam which rotates integrally with the second chronograph counter axle; a jumper configured to cooperate with a positioning cam to ensure that the positioning cam is held in said angular reference position of the second chronograph counter display when the chronograph mechanism is stopped; Including, - said positioning cam is superimposed on said second chronograph counter wheel; - the positioning cam has a convex relief, the convex relief being configured to cooperate with a complementary relief of the concave jumper, the concave jumper being configured to receive and accommodate the convex relief of the positioning cam; - the positioning cam has a concave relief, the concave relief being adapted to cooperate with a complementary convex relief of a jumper adapted to be received in the concave relief of the positioning cam; - the positioning cam further forms a reset cam for the second chronograph counter, - the positioning cam is in the shape of a heart, and the jumper cooperates with a tip of the heart to hold the second chronograph counter display in said angular reference position when the chronograph is stopped; - the jumper has a concave relief adapted to cooperate with a tip of the heart of the positioning cam forming a convex relief, - the jumper has a convex relief configured to cooperate with a concave relief formed on the tip of the heart of the positioning cam; - the jumper is an integral part including a part which cooperates with the positioning cam in a resiliently movable manner; - the jumper includes a lever that can be rotated about an axis of rotation, the lever cooperating with a resilient member that operates to position the lever so that it rests against a positioning cam; - The position of the lever's rotation axis can be adjusted by eccentricity to fine-tune the angle reference position of the second chronograph counter display; - the chronograph mechanism includes a gear train disposed between the seconds counter and the second chronograph counter, said gear train including said inter-counter wheel; - said angular reference position of the second chronograph counter display is a reference position or a reset position, The second chronograph counter is a chronograph hour counter or a chronograph minute counter.

[0018] Another aspect of the invention relates to a timepiece movement including a chronograph mechanism according to the invention.

[0019] The invention further relates to a timepiece comprising a timepiece movement according to the invention.

[0020] The timepiece is, for example, a wristwatch including a watch case adapted to receive and house a timepiece movement according to the invention. [Brief description of the drawings]

[0021] The objects, advantages and features of the present invention will be better understood upon reading the detailed description given below in conjunction with the following drawings, in which:

[0022] [Figure 1] FIG. 1 is a schematic perspective view of a first embodiment of a chronograph mechanism according to the invention, comprising a position-holding device for holding a chronograph counter in a fixed position, in particular in a reference position; [Diagram 2] FIG. 2 is a top view of the chronograph mechanism of FIG. 1. [Diagram 3] FIG. 2 is a bottom view of the chronograph mechanism of FIG. 1. [Figure 4] FIG. 2 is a functional block diagram of the chronograph mechanism of the timepiece movement according to the invention shown in FIG. 1, illustrating the interaction of the various elements of the timepiece movement with the various elements of the chronograph mechanism. [Diagram 5] FIG. 2 is a perspective view of a second embodiment of a chronograph mechanism according to the invention, comprising a position-holding device for holding a chronograph counter in a fixed position, in particular in a reference position;

[0023] In all figures, common elements are given the same reference numbers unless otherwise specified. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] FIG. 1 is a schematic perspective view of a first embodiment of a chronograph mechanism 10 according to the invention, comprising a position-holding device 240 for holding a chronograph counter in a fixed position, in particular a reference position.

[0025] FIG. 2 is a top view of the chronograph mechanism 10 of FIG.

[0026] FIG. 3 is a bottom view of the chronograph mechanism 10 of FIG.

[0027] FIG. 4 is a functional block diagram of the chronograph mechanism 10 of the timepiece movement 1 according to the invention, illustrating the interaction of the various elements of the timepiece movement 1 with the various elements of the chronograph mechanism 10, which will be explained below.

[0028] Conventionally, the chronograph mechanism 10 is coupled to a running train 110 of the time movement 1, dedicated to the time scale, via a coupling device 115, and is arranged to be driven on demand. Conventionally, the running train 110 is regulated by a regulating member 120.

[0029] Conventionally, the operating train 110 drives the hands of the time display, in particular the hour hand which cooperates with the hour scale, the minute hand which cooperates with the minute scale, and the second hand which cooperates with the second scale.

[0030] The chronograph mechanism 10 includes a chronograph train 20. The chronograph train 20 includes a first chronograph counter 210. The first chronograph counter 210 is configured to be driven by a running train and configured to be regulated in time to a regulating member 120 of the timepiece movement 1 via a coupling device 115. Conventionally, this first chronograph counter 210 is a chronograph seconds counter.

[0031] The chronograph seconds counter 210 includes a seconds wheel 212, also called chronograph wheel. The seconds wheel 212 is attached to a seconds stem 211. The seconds stem 211 carries and is rigidly connected to a chronograph seconds display 214, for example a chronograph seconds hand.

[0032] The chronograph seconds counter 210 includes a drive finger 215 that rotates integrally with the seconds axle 211. The drive finger 215 is configured to drive the inter-counter wheel 23 in a step manner each time the chronograph seconds counter 210 makes one complete revolution.

[0033] In the illustrated embodiment, drive fingers 215 are flexible drive fingers, although other configurations are possible while still remaining within the scope of the invention.

[0034] The chronograph train 20 includes at least one second chronograph counter 220. The second chronograph counter 220 includes a second chronograph counter wheel 222 mounted on a second chronograph counter axle 221. The second chronograph counter axle 221 carries and is rigidly connected to a second chronograph counter display 224, e.g. a hand.

[0035] The second chronograph counter 220 may be a chronograph minute counter or a chronograph hour counter.

[0036] The position-holding device 240 for holding the chronograph mechanism 10 according to the present invention in a fixed position makes it possible to hold the chronograph counter with which it is associated in a fixed position, and in this embodiment makes it possible to hold the second chronograph counter 220 only in a pre-determined angular position of the counter display, preferably only in a reference position of the display, for example only in the reset position of the display, when the chronograph mechanism 10 is stopped.

[0037] Preferably, the second chronograph counter 220 is an hour counter, and the chronograph mechanism 10 according to the invention comprises a position-holding device 240 which holds the hour counter in a fixed position, in particular in a reference position.

[0038] In particular, the position-holding device 240 according to the invention is particularly useful when associated with an hour counter, since, notably due to the various gear clearances present in the gear train 250 provided between the chronograph seconds counter 210 and the chronograph hour counter (in this case the second chronograph hour counter 220), a wobble in the hour display is visible to the user after resetting.

[0039] The gear train 250 includes an inter-counter wheel 23 which is driven in a step each time the seconds counter 210 makes a complete revolution.

[0040] In the embodiment shown, the gear train 250 further comprises two intermediate wheels 24, 25 arranged between the inter-counter wheel 23 and the second chronograph counter 220, in order to obtain a desired gear ratio in the second chronograph counter wheel 222.

[0041] For example, if the second chronograph counter 220 is an hour counter making one complete rotation in 12 hours, the gear train 250 is shaped to obtain a reduction ratio of 1 / 24 with the inter-counter wheel 23 including 30 teeth and driven at one step per minute.

[0042] The intercounter wheel 23 cooperates with a jumper 30 having a beak terminating in two inclined surfaces configured to cooperate with the tips of two successive teeth of the intercounter wheel 23 to maintain the angular position of the intercounter wheel 23 at each step.

[0043] Preferably, the jumper 30 includes adjustment means for adjusting the relative position of the jumper 30 with respect to the inter-counter wheel 23. This enables the jumper 30 to correct the angular position of the inter-counter wheel 23 in order to accurately position the inter-counter wheel 23 with respect to the drive finger 215 of the seconds counter 210.

[0044] Advantageously, the position maintaining device 240 is a reference position maintaining device configured to ensure that the second chronograph counter display 224 is stably maintained in a reference position, in particular after a reset of the chronograph counter when the second chronograph counter wheel 222 and the various wheel sets of the gear train 250 are no longer in driving contact with the running train 210.

[0045] That is, the position maintaining device 240 ensures that when the second chronograph counter display 224 is in a reference position and the chronograph train 20 is not driven by the running train 110 of the clock movement 1, the second chronograph counter display 224 is stably maintained in the reference position.

[0046] The position maintaining device 240 is a positioning cam 226 which rotates integrally with the stem of the second chronograph counter 221; a jumper 242 configured to cooperate with the positioning cam 226; Includes.

[0047] The positioning cam 226 is a separate part from the second chronograph counter wheel 222 .

[0048] The positioning cam 226 is superimposed on the second chronograph counter wheel 222 such that the jumper 242 only interacts with the positioning cam 226 and not with the second chronograph counter wheel 222 .

[0049] As a result, it becomes completely clear that the position-holding device 240 according to the present invention is different from an index device configured to index each step or angular position of the second chronograph counter by interacting with the teeth of the second chronograph counter wheel 222.

[0050] The positioning cam 226 has a relief 229 which is arranged to cooperate with a complementary relief 242.2 of the jumper 242. That is to say, the positioning cam 226 has only one possible index position.

[0051] In the first embodiment shown in figures 1 to 3, the positioning cam 226 further forms a reset cam which resets the second chronograph counter 220. Such an embodiment allows combining two functions in the same part, using two different areas of the heart shape, thereby minimizing the overall dimensions of the chronograph mechanism 10.

[0052] For example, the positioning cam 226 is in the shape of a heart. In this embodiment, the tip of the heart joining the two lobes 227, 228 forms a relief 229 of the positioning cam 226.

[0053] That is to say, the tip of the heart forms a convex relief 229 that is configured to cooperate with the jumper 242, and in particular with a complementary relief 242.3 in the form of a recess in the jumper 242. The complementary relief 242.3 is configured to receive and accommodate the tip of the heart of the positioning cam 226, thus retaining the positioning cam 226 in this particular angular position when no driving force is exerted on the chronograph train 20 or the second chronograph counter 220.

[0054] In an alternative embodiment, a recess may be formed at the end of the heart-shaped tip to cooperate with a complementary convex relief formed in the jumper 242 .

[0055] The jumper 242 may be a unitary part, a portion of which is resiliently movable and configured to cooperate with the positioning cam 226 .

[0056] According to the embodiment shown in Figures 1 to 3, the jumper 242 comprises a lever 242.1 rotatable about an axis of rotation 243. The lever 242.1 cooperates with a resilient member 242.2 which acts to position the lever 242.1 so that it abuts against the positioning cam 226.

[0057] The elastic member 242.2 is shaped in such a way that the lever 242.1 generates a low frictional force on the smooth parts of the positioning cam 226, but a high frictional force when the relief of the positioning cam 226 and the relief of the jumper 242 cooperate to hold the second chronograph counter display 224 in the reference position. That is, a certain torque must be applied to the second chronograph counter 220 in order for the relief 229 of the positioning cam 226 to disengage from the relief 242.3 of the jumper 242. For example, starting the chronograph mechanism 10 which drives the chronograph train 10 generates a torque in the second chronograph counter 220 sufficient to disengage the reliefs 229, 242.3 of the positioning cam 226 and the jumper 242, respectively.

[0058] In general, the jumper 242 is configured to generate a positioning torque for the positioning cam 226 sufficient to overcome any imbalance that may be present in the second chronograph counter display 224, for example during a small shock to the timepiece movement 10.

[0059] Without any specific action (resetting or starting) to the chronograph train 20, the engagement of the relief 229 of the positioning cam 226 with the complementary relief 242.3 of the jumper 242 prevents the second chronograph counter display 224 from wobbling and ensures that the second chronograph counter display 224 is held in a constant position, preferably a reference position, unless the chronograph mechanism 10 is started.

[0060] The position-retaining device 240 according to the invention thus provides a solution that allows a reduction in power consumption, since the peak power consumption when the second chronograph counter 220 completes one full revolution is only in the path of the relief 229 of the positioning cam 226. Outside the path of the relief 229, the friction forces occurring between the smooth parts of the positioning cam 226 and the jumper 242 are negligibly small.

[0061] The position of the axis of rotation 243 of the lever 242, more precisely of the lever 242.1, can be adjusted by means of the eccentric 241, which allows the position of the lever 242.1 and of the complementary relief 242.3 to be precisely adjusted so that the angular holding position of the second chronograph counter display 224 with respect to the scale of the dial is ultimately corrected, i.e. the eccentric 241 makes it possible to adapt to the different manufacturing tolerances of the various components of the timepiece movement 1 and to fine-tune the angular holding position of the second chronograph counter display 224.

[0062] 5 shows a second embodiment of the chronograph mechanism 10 according to the invention, which is the same as the first embodiment except for the features described below.

[0063] In this second embodiment, the positioning cam 446 is disengaged from the reset cam of the second chronograph counter 220 .

[0064] The positioning cam 446 has the form of a smooth wheel with a circular cam track with a concave relief 447. The concave relief 447 is arranged to cooperate with the convex relief 444 of the jumper 442. Naturally, the reverse arrangement is also possible.

[0065] As in the first embodiment, the jumper 442 may be formed by a lever 442.1 rotatable about an axis of rotation 443 and cooperating with a resilient member 442.2. The resilient member 442.2 is adapted to engage with the lever 442.1 by a positioning cam. 446 442.1 to abut against the

[0066] The invention further relates to a timepiece, such as a wristwatch, comprising such a timepiece movement.

Claims

1. A chronograph mechanism (10) for a timepiece movement (1) having a chronograph train (20), comprising: a seconds counter (210) forming a first chronograph counter, said seconds counter (210) comprising a seconds counter axle (211) carrying a seconds counter display (214), a seconds counter wheel (212) and a drive finger (215) configured to drive an inter-counter wheel (23) in a stepwise manner for each revolution of said seconds counter wheel (212); a second chronograph counter (220) having a second chronograph counter axle (221) carrying a second chronograph counter display (224) and a second chronograph counter wheel (222) actuated by the inter-counter wheel (23); Including, the chronograph mechanism (10) includes a position-holding device (240) that holds the second chronograph counter display (224) in a fixed position; The chronograph mechanism (10), characterized in that the position-maintaining device includes a positioning cam (226, 446) that rotates together with an axle of the second chronograph counter (221) to ensure that the second chronograph counter display (224) is maintained in a constant position only when the second chronograph counter display (224) is in an angular reference position and when the chronograph mechanism (10) is stopped, and a jumper (242, 442) configured to cooperate with the positioning cam (226, 446).

2. A chronograph mechanism (10) as described in claim 1, characterized in that the jumper (242, 442) is configured to ensure that the positioning cam (226, 446) is maintained in a constant position when the second chronograph counter (224) is in the angular reference position and when the chronograph mechanism (10) is stopped.

3. 3. The chronograph mechanism (10) according to claim 2, characterized in that said positioning cam (226, 446) is superimposed on said second chronograph counter wheel (222).

4. 3. The chronograph mechanism (10) according to claim 2, characterized in that the positioning cam (226) has a convex relief (229) configured to cooperate with a complementary relief (242.3) of the jumper (242) configured to receive and accommodate the convex relief (229) of the positioning cam (226).

5. 3. The chronograph mechanism (10) according to claim 2, characterized in that said positioning cam (446) has a concave relief (444) configured to cooperate with a complementary relief (447), which is a convex relief of said jumper (442) configured to be received in said concave relief (444) of said positioning cam (446).

6. 3. The chronograph mechanism (10) according to claim 2, characterized in that said positioning cam (226) further forms a reset cam for said second chronograph counter (220).

7. 7. The chronograph mechanism (10) according to claim 6, characterized in that the positioning cam (226) is heart-shaped, and the jumper (242) cooperates with an end of the heart to hold the second chronograph counter display (224) in the angular reference position when the chronograph mechanism (10) is stopped.

8. 8. The chronograph mechanism (10) according to claim 7, characterized in that the jumper (242) has a concave relief (242.3) configured to cooperate with a heart-shaped tip of the positioning cam (226) forming a convex relief (229).

9. 8. The chronograph mechanism (10) according to claim 7, characterized in that said jumper (242) has a convex relief configured to cooperate with a concave relief formed in the tip of the heart of said positioning cam (226).

10. 3. The chronograph mechanism (10) according to claim 2, characterized in that said jumper is an integral part, a part of which cooperates with said positioning cam (226, 446) by being capable of elastically moving said positioning cam (226, 446).

11. 3. The chronograph mechanism (10) according to claim 2, characterized in that the jumper (242, 442) includes a lever (242.1, 442.1) rotatable about an axis of rotation (243, 443), the lever (242.1, 442.1) abutting against the positioning cam (226, 446) by cooperating with an elastic member (242.2, 442.2) which operates to position the lever (242.1, 442.1).

12. 12. The chronograph mechanism (10) according to claim 11, wherein the position of the axis of rotation (243, 443) of the lever (242.1, 442.1) can be adjusted by an eccentric (241) to fine-tune the angular reference position of the second chronograph counter display (224).

13. 2. The chronograph mechanism (10) according to claim 1, further comprising a gear train (23, 24, 25) arranged between said seconds counter (210) and said second chronograph counter (220), said gear train including said inter-counter wheel (23).

14. 2. The chronograph mechanism (10) according to claim 1, characterized in that the angular reference position of the second chronograph counter display (224) is a reset position.

15. 2. The chronograph mechanism (10) according to claim 1, characterized in that said second chronograph counter (220) is a chronograph hour counter.

16. A timepiece movement (1) including a chronograph mechanism (10) according to claim 1.

17. A timepiece including a timepiece movement (1) according to claim 16.

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