Timepiece movement including a chronograph mechanism

Abstract

One aspect of the invention relates to a clockwork movement (100) comprising: a timekeeping gear train (110) driven by a first energy source (50); a regulating member (120) for regulating the timekeeping gear train (110); a chronograph mechanism (130) comprising a chronograph gear train (140) driven by a second energy source (40); a clutch (150) configured to couple the chronograph gear train (140) to the regulating member (120) on demand in order to regulate the chronograph gear train (140) from the regulating member (120); a chronograph start / stop control device (250) cooperating with the clutch (150); characterized in that the clutch (150) is a differential clutch comprising: a first input wheel (151) driven by said time gear (110) and having a rotation speed regulated by the regulating member (120); an output wheel (152) meshed with said chronograph gear (140);a second free-running input wheel (153) cooperating directly or indirectly with the chronograph start / stop control device (250); the clutch (150) comprising a drive assembly (165, 166) configured to rotate the output wheel (152) at said regulated rotational speed of the regulating member (120), when the rotation of the second input wheel (153) is blocked via the chronograph start / stop control device (250).

Description

Technical field of the invention

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

[0002] More particularly, the invention relates to a timepiece movement comprising a chronograph mechanism cooperating with an auxiliary energy source different from a main energy source dedicated to the movement and to the indication of the time.

[0003] More particularly, the invention relates to a clutch for coupling the rapidly regulating member of the watch movement to the chronograph mechanism when the chronograph mechanism is activated.

[0004] The invention also relates to a timepiece comprising such a timepiece movement. Technological background

[0005] Existing mechanical watch movements comprising a chronograph mechanism have disadvantages, such as variation in the rate of the movement or variation in the amplitude of the regulating organ between the different activation states of the chronograph mechanism, for example between the running and stopping of the chronograph.

[0006] These variations in the rate of the movement or the isochronism of the regulating organ come at least in part from the fact that the energy consumed is not the same depending on the function engaged (start or stop in particular) of the chronograph mechanism.

[0007] One of the proposed solutions to this drawback is to separate the chronograph gear train from the main power source of the time train of the watch movement, in order to dedicate this power source exclusively to the time train and the time indication. Thus, the power reserve of the watch movement does not depend on the activation state (on or off) of the chronograph mechanism.

[0008] Such a solution is notably described in patent CH 703 797 B1. This document describes the use of a main barrel driving a time train actuating an hour display and a minute display, a regulating organ comprising a balance spring and an escapement, regulating the time train, as well as the use of a secondary barrel dedicated to the chronograph mechanism and to driving a chronograph train. A clutch makes it possible to couple and regulate the chronograph train from the regulating organ of the movement when activating the chronograph mechanism via a chronograph start / stop control device.

[0009] The proposed clutch comprises a wolf tooth secured to the escape wheel cooperating with a clutch wheel bearing a jumping seconds pinion shaft, a first 6-tooth star secured to the jumping seconds pinion and a second six-tooth star mounted freely on the jumping seconds pinion shaft and connected to the first star by a pin passing through an oblong slot in the second star.

[0010] However, such a clutch is complex to produce, bulky and requires making the escape wheel, which is an extremely sensitive part in a watch movement, more complex.

[0011] Additionally, such a clutch has a different energy consumption between starting and stopping the chronograph movement, which poses problems.

[0012] Therefore, there is a need to improve watch movements equipped with a chronograph mechanism powered by a power source different from the main power source of the time train for time indication. Summary of the invention

[0013] In this context, the invention proposes a watch movement comprising a chronograph mechanism and a clutch making it possible to couple on demand, instantly, and with low consumption of driving energy, the chronograph mechanism to the regulating organ of the movement.

[0014] In this context, the invention relates to a clockwork movement comprising: a time train dedicated to the division of time of said clockwork movement, said time train being driven by a first energy source; a regulating member for regulating the time train; a chronograph mechanism comprising a chronograph train driven by a second energy source; a clutch configured to couple the chronograph train to the regulating member on demand to regulate the chronograph train from the regulating member; a chronograph start / stop control device cooperating with the clutch; characterized in that the clutch is a differential clutch comprising: a first input wheel driven by said time train and having a rotation speed regulated by the regulating member; an output wheel meshed with said chronograph train; a second idle input wheel cooperating directly or indirectly with the chronograph start / stop control device; the clutch comprising a drive assembly configured to rotate the output wheel at said regulated rotation speed of the regulating member, when the second input wheel is blocked in rotation via the chronograph start / stop control device.

[0015] In addition to the characteristics mentioned in the preceding paragraph, the clockwork movement according to the invention may have one or more additional characteristics among the following, considered individually or in all technically possible combinations: the differential clutch is a ball differential clutch; the first input wheel is integrated into the time train; the output wheel is parallel to the first input wheel, the output wheel meshing directly or indirectly with the chronograph train; the first input wheel and the output wheel are coaxial; the drive assembly is formed by balls carried by the second input wheel and configured to roll between the first input wheel and the output wheel, and by an elastic element configured to push the first input wheel and the output wheel towards each other, so as to generate a rolling without slippage of the balls in contact with the first input wheel and the output wheel; the elastic element is a spring washer; said time train drives an hour display and a minute display; the second energy source is dedicated to the chronograph train;said second energy source is a barrel; the chronograph gear train comprises a chronograph minute counter and a chronograph second counter; the chronograph gear train comprises a fractional second counter; the chronograph mechanism comprises a reset mechanism for resetting at least one of the chronograph counters included in the chronograph gear train; the regulating member comprises a high-frequency oscillator having an oscillation frequency greater than or equal to 5 Hz; the chronograph start / stop control device comprises a clutch lever configured to block the free rotation of the second input wheel when a start / stop control member is activated.;

[0016] Another aspect of the invention relates to a timepiece comprising such a timepiece movement according to the invention. The timepiece is preferably a wristwatch comprising a watch case configured to receive and house the timepiece movement according to the invention. Brief description of the figures

[0017] The aims, advantages and characteristics of the present invention will appear on reading the detailed description below with reference to the following figures: there figure 1 is a schematic representation in plan view of a clockwork movement according to the invention; the figure 2 is a functional block diagram of the clockwork movement according to the invention illustrated in figure 1 ; there figure 3 is a sectional view of a differential clutch of the clockwork movement according to the invention.

[0018] In all figures, common elements bear the same reference numbers unless otherwise specified. Detailed description of the invention

[0019] There figure 1 shows a schematic representation in plan view of a clockwork movement 100 according to the invention.

[0020] There figure 2 is a functional block diagram of the clockwork movement 100, according to the invention, illustrated in figure 1 to illustrate the interactions between the different elements of the clockwork movement 100 which will be described later.

[0021] The clockwork movement 100 according to the invention comprises a time train 110 dedicated to the division of time, and driven by a first energy source 50, called the main energy source.

[0022] The first energy source 50 is for example a barrel constituting an energy reserve to power the time train 110.

[0023] The time train 110 drives the hands of a time display, in particular an hour hand 111 cooperating with an hour scale, a minute hand 112 cooperating with a minute scale and a second hand 113, or second hand, cooperating with a second scale.

[0024] The 110 hour train traditionally comprises an hour wheel carrying the hour hand 111 of the time display, a minute wheel carrying the minute hand 112 of the time display and a second wheel carrying the second hand 113 of the time display.

[0025] The 110 hour gear train can also include intermediate wheels if necessary.

[0026] The 110 hour gear train is regulated by a 120 regulating organ.

[0027] The regulating organ 120 traditionally comprises an oscillator 121 and an escapement 122.

[0028] Oscillator 121 is a mechanical or electrical oscillator.

[0029] For example, oscillator 121 is a mechanical oscillator of the sprung balance type. Such a sprung balance has, for example, an oscillation frequency of between 2.5 and 4 Hz.

[0030] For example, oscillator 121 is a high-frequency mechanical or electrical oscillator, i.e. oscillating at a frequency greater than 4Hz.

[0031] For example, oscillator 121 is a high-frequency mechanical or electrical oscillator, i.e. oscillating at a frequency greater than or equal to 5Hz.

[0032] The 100 clockwork movement further includes a 130 chronograph mechanism.

[0033] The chronograph mechanism 130 comprises a chronograph train 140 driven by a second energy source 40, called the secondary energy source, which is different from the main energy source 50.

[0034] Thus, the entire chronograph gear train 140 is powered by the second energy source 40, independently of the first energy source actuating the time gear train 110.

[0035] Preferably, this second energy source 40 is dedicated to driving the chronograph gear train 140. However, it is also possible to use this second energy source 40 to power an additional complication of the timepiece movement 100.

[0036] The second energy source 40 is for example a barrel constituting an energy reserve dedicated to the chronograph gear train 140. For this purpose, the barrel is sized to provide the energy necessary for the operation of the chronograph mechanism 130.

[0037] Thus, when the first energy source 50 and the second energy source 40 are barrels, all the energy consumed by the chronograph train 140 is delivered by the second barrel 40 and all the energy of the first barrel 50 is used solely for the time train 110, which makes it possible to increase the power reserve of the time train 110.

[0038] The 140 chronograph train includes a 141 chronograph minute counter and a 142 chronograph second counter.

[0039] The 141 chronograph minute counter has a 144 minute counter wheel driving a 145 chronograph minute hand.

[0040] The chronograph seconds counter 142 has a seconds counter wheel 146 driving a chronograph seconds hand 147.

[0041] In the example shown, the chronograph gear train 140 further comprises a fractional second counter 143, or jumping seconds counter, having a jumping seconds pinion 148 driving a jumping seconds chronograph hand 149.

[0042] The chronograph train 140 includes intermediate chronograph wheels to obtain the desired ratios between the different counters 141, 142, 143. In addition, the chronograph train 140 may also include additional intermediate wheels depending on the needs and architectures of the movement and the installation of the minute counters 141, seconds 142 and jumping seconds 143 in the timepiece movement 100.

[0043] The minute counters 141, seconds 142 and jumping seconds 143 conventionally comprise a reset cam, for example in the shape of a snail, heart, or other, for resetting, in a reference position, the counters by means of a reset mechanism 200 of the chronograph counters (visible on the block diagram of the figure 2 ).

[0044] The reset mechanism 200 traditionally comprises a reset control 210 that can be manipulated by the user, for example via a push button or an actuating pad. The reset control 210 cooperates directly or indirectly with a reset hammer 220 cooperating with the respective reset cams of the different counters 141, 142, 143.

[0045] Since the reset mechanism 200 is a conventional mechanism for resetting chronograph counters and is known to those skilled in the art, there is no need to describe it further for the implementation of the invention.

[0046] The clockwork movement 100 includes a clutch 150 configured to: coupling on request the chronograph train 140 to the regulating organ 120 of the watch movement 100 in order to be able to regulate the chronograph train 140, and consequently the various chronograph counters 141, 142, 143 at the rate of the regulating organ 120; decoupling the chronograph train 140 from the regulating organ 120 to stop the chronograph train 140 and the various hands 145, 147, 149 of the chronograph counters 141, 142, 143.

[0047] Thus, the clutch 150 makes it possible to kinematically connect, on demand, via a chronograph start / stop control device 250 the chronograph gear train 140 to the escapement 122.

[0048] There figure 3 is a sectional view of a clutch 150 of the clockwork movement 100 according to the invention.

[0049] The clutch 150 is a differential clutch comprising as first input the time train 110, as second input the start / stop control device of the chronograph 250 and as output the chronograph train 140.

[0050] More specifically, the differential clutch 150 comprises: a first input wheel 151 driven by the time train 110 and therefore having a rotation speed regulated by the regulating member 120; an output wheel 152 meshed with said chronograph train 140; a second input wheel 153 idler cooperating directly or indirectly with the chronograph start / stop control device 250.

[0051] The output wheel 152 is parallel to the first input wheel 151.

[0052] Preferably, the first input wheel 151 and the output wheel 152 are coaxial.

[0053] Preferably, the first input wheel 151, the second input wheel 153 and the output wheel 152 are coaxial.

[0054] The differential clutch 150 also comprises a drive assembly 165, 166 configured to rotate the output wheel 152 at said regulated rotation speed of the regulating member 120, when the second input wheel 153 is blocked in rotation via the chronograph start / stop control device 250.

[0055] Preferably, the differential clutch 150 is a ball differential clutch. Thus, the drive assembly is formed by the cooperation of balls 165 and an elastic element, formed by a spring washer 166, ensuring the rolling without slipping of the balls 165 on the first input wheel 151 and the output wheel 152.

[0056] The first input wheel 151 is secured to a clutch shaft 155. An input pinion 161 is riveted to the clutch shaft 155 so that the input pinion 161 and the first input wheel 151 form an input wheel.

[0057] For example, the input wheel set is integrated into the time train 110. In the exemplary embodiment, the input wheel set is interposed between a seconds wheel set 115 of the time train 110 and a multiplier wheel set 116 meshed with the escapement 122. Thus, the input wheel set is integrated into a first kinematic chain formed by the entire gear train between the first energy source 50 and the regulating member 120.

[0058] More particularly, the first input wheel 151 is meshed with the multiplier wheel 116 and the input pinion 161 is meshed with the seconds wheel 115 of the time train 110.

[0059] The output wheel 152 of the differential clutch 150 is at the end of the kinematic chain of the chronograph gear train 140. Thus a second kinematic chain is formed between the second energy source 40 and the differential clutch 150, and particularly the output wheel 152.

[0060] The output wheel 152 is mounted freely around the clutch shaft 155, for example by means of a ball bearing 156.

[0061] The second input wheel 153 is an idler wheel mounted to rotate freely around the clutch axis 155. The second input wheel 153 makes it possible to control the coupling between the first input wheel 151 and the output wheel 152.

[0062] The balls 165 ensuring the rotational drive of the output wheel 152 are arranged through the plate 157 of the second input wheel 153. The balls 165 bear on the first input wheel 151 and on the output wheel 152.

[0063] The first input wheel 151 and the output wheel 152 are held under tension by the spring washer 166 ensuring rolling without slippage of the balls 165 on the board of the first input wheel 151 and on the board of the output wheel 152.

[0064] Such a differential clutch 150 thus makes it possible, when activating the chronograph mechanism 130 by the chronograph start / stop control device 250, to couple the chronograph gear train 140, via the output wheel 152, with the time gear train 110 regulated by the regulating member 120 via the first input wheel 151.

[0065] The chronograph start / stop control device 250 comprises a start / stop control member 252 setting in motion a clutch lever 251 which is configured to block the free rotation of the second input wheel 153. The start / stop control member 252 can be formed by the assembly of a start control and a stop control, the two controls not necessarily being merged into a single member.

[0066] The coupling by blocking the rotation of the second input wheel 153 makes it possible to rotate the output wheel 152 with the regulation of the regulating member 120 of the time train 110.

[0067] Such animation is enabled by the slip-free rolling of the balls 165 on the respective boards of the first input wheel 151 and the output wheel 152.

[0068] In the illustrated configuration, the first input wheel 151 and the output wheel 152 have the same speed and rotation rate but with opposite direction.

[0069] When the chronograph mechanism 130 is stopped, the clutch lever 251 releases the second input wheel 153 so as to allow it to rotate freely. This has the effect of uncoupling the output wheel 152 and the first input wheel 151. In this stopped position of the chronograph mechanism 130, the output wheel 152 is stopped, and the two input wheels 151, 153 are rotatable.

[0070] The chronograph start / stop control device 250 may also include conventional means for maintaining the chronograph counters in position when the chronograph is stopped.

[0071] Such a differential clutch 150, preferably with balls like that presented in the present application, makes it possible to regulate on demand a complication, for example a chronograph mechanism 130, having a dedicated energy source 40.

[0072] Thus, such a differential clutch 150 makes it possible to avoid the use of a second regulating member with the synchronization complications that this implies.

[0073] The differential clutch 150 according to the invention makes it possible to very quickly couple and uncouple a complication, here a chronograph mechanism 130.

[0074] The differential clutch 150 according to the invention is a responsive and high-precision clutch due to the reliable clearances to be taken up between the engaged position (active chronograph mechanism) and the disengaged position (inactive chronograph mechanism) of the clutch.

[0075] Therefore, such a differential clutch is particularly suitable for a watch movement comprising a high-frequency oscillator and / or a foudroyante chronograph mechanism displaying divisions of a second. Indeed, these two application examples require a high reactivity of such a clutch, taking into account the very small division of time (fraction of a second) and / or the high frequency of the oscillations of a high-frequency oscillator.

[0076] The invention also relates to a timepiece, for example a wristwatch, comprising such a timepiece movement.

Claims

1. Horological movement (100) comprising: - a running train (110) dedicated to the time division of said horological movement, said running train (110) being driven by a first energy source (50); - a regulating member (120) for regulating the running train (110); - a chronograph mechanism (130) comprising a chronograph train (140) driven by a second energy source (40); - a coupling (150) configured to couple the chronograph train (140), on demand, to the regulating member (120) to regulate the chronograph train (140) using the regulating member (120); - a chronograph start / stop control device (250) cooperating with the coupling (150); characterised in that the coupling (150) is a differential coupling comprising: - a first input wheel (151) driven by said running train (110) and having a rotational speed that is regulated by the regulating member (120); - an output wheel (152) meshed with said chronograph train (140); - a second input wheel (153), which is an idle wheel, cooperating directly or indirectly with the chronograph start / stop control device (250); the coupling (150) comprising a drive assembly (165, 166) configured to rotate the output wheel (152) at said rotational speed regulated by the regulating member (120), when the rotation of the second input wheel (153) is blocked by the chronograph start / stop control device (250).

2. Horological movement (100) according to the preceding claim, characterised in that said differential coupling (150) is a differential ball coupling.

3. Horological movement (100) according to one of the preceding claims, characterised in that the first input wheel (151) is integrated into the running train (110).

4. Horological movement (100) according to one of the preceding claims, characterised in that the output wheel (152) is parallel to the first input wheel (151), the output wheel (152) meshing directly or indirectly with the chronograph train (140).

5. Horological movement (100) according to one of the preceding claims, characterised in that the first input wheel (151) and the output wheel (152) are coaxial.

6. Horological movement (100) according to one of the preceding claims, characterised in that the drive assembly is formed by balls (165) carried by the second input wheel (153) and configured to roll between the first input wheel (151) and the output wheel (152), and by a resilient element (166) configured to push the first input wheel (151) and the output wheel (152) towards one another, so as to generate a non-slip rolling of the balls (165) in contact with the first input wheel (151) and the output wheel (152).

7. Horological movement (100) according to the preceding claim, characterised in that the resilient element (166) is a spring washer.

8. Horological movement (100) according to one of the preceding claims, characterised in that said running train (110) drives an hour display (111) and a minute display (112).

9. Horological movement (100) according to one of the preceding claims, characterised in that said second energy source (40) is dedicated to the chronograph train (140).

10. Horological movement (100) according to one of the preceding claims, characterised in that said second energy source (40) is a barrel.

11. Horological movement (100) according to one of the preceding claims, characterised in that the chronograph train (140) comprises a chronograph minute counter (141) and a chronograph seconds counter (142).

12. Horological movement (100) according to one of the preceding claims, characterised in that the chronograph train (140) comprises a fraction-of-second counter (143).

13. Horological movement (100) according to one of claims 11 to 12, characterised in that the chronograph mechanism (130) comprises a zero-reset mechanism (200) for zero-resetting at least one of the chronograph counters (141, 142, 143) comprised in the chronograph train (140).

14. Horological movement (100) according to one of the preceding claims, characterised in that the regulating member (120) comprises a highfrequency oscillator (121) with an oscillation frequency greater than or equal to 5 Hz.

15. Horological movement (100) according to one of the preceding claims, characterised in that the chronograph start / stop control device (250) comprises a coupling yoke (251) configured to block the free rotation of the second input wheel (153) when a start / stop control member is activated (252).

16. Timepiece comprising a horological movement (100) according to one of the preceding claims.

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