EP2802941B1 - Regulating member for a mechanical chronograph - Google Patents

Description

Technical area

The present invention relates to an escapement for a horological movement, and in particular a mechanical regulating member with an escapement capable of sustaining and counting isochronous oscillations of a vibrating oscillator.

In one embodiment, the present invention relates to high frequency mechanical chronographs enabling time periods of measurement with a resolution better than 1/1000 ^th of a second, and having a vibrating oscillator with a frequency equal to or greater to a few tens of Hz, for example a frequency equal to or greater than 1 kHz. However, the regulating member of the invention can also operate at lower frequencies, from a few tens of Hz.

State of the art

The precise measurement of time over a given period amounts to adding the N first whole fractions of time counted over the period. A distinction should be made between measuring and counting time: to count an interval of time, for example a second, it is necessary to know how to divide it into equal fractions, for example in tenths or hundredths.

Thus, it is not possible to count less than a unit of measurement without cutting it more finely. To measure directly, the position of a needle whose movement is the result of a count must be noted.

There are certainly chronographs which make it possible to interpolate the whole fractions of time counted, in order to improve the displayed resolution. For example, there are chronographs equipped with a 5Hz oscillator which display, by interpolation, durations of less than a tenth of a second; one could also without further imagine chronographs fitted with a 50Hz oscillator, for example, and capable of displaying times with a resolution of one thousandth of a second. The interpolation can for example be carried out by determining the angular position of a hand, of a gear train, of the balance, or of the axis of the balance, for example by means of a cam rotating at each alternation with the balance and whose angular position determines the fraction of alternation in which we are at each instant. Such interpolation is in no way capable of counting or displaying the precise interval.

The precise mechanical measurement of periods of time therefore requires an oscillator having a natural frequency corresponding to the resolution that one wishes to obtain, as well as an escapement capable of sustaining these oscillations without disturbing their isochronism, and of counting it. By increasing the frequency of oscillation, the temporal resolution is improved, which makes it possible to distinguish very close intervals of duration. Improved temporal resolution is especially useful for chronographs, for which a temporal resolution of the order of a hundredth of a second is sometimes desired. A high oscillation frequency, however, generates energy consumption, particularly at the level of the escapement, which reduces the power reserve of the watch.

On the other hand, the incident energy which feeds the regulator in a traditional mechanical watch is done by means of a discontinuous system, the anchor wheel and the anchor. Traditionally, an escapement stops then accelerates at each alternation to communicate energy to the regulator. It is therefore necessary each time to "relaunch" the escape wheel, as well as the entire cog train which also stops and then restarts at each alternation. The overall inertia of this system induces a limit in the acceleration that the anchor wheel can receive and therefore in the energy transmitted. A conventional sprung balance system, associated with a given mechanical transmission chain, therefore has a frequency limit and corollary a limit in operating time.

For this reason, the chosen oscillation frequency is usually a compromise between the resolution requirements of the chronograph and the desire to maintain a high power reserve for the display of the current time.

The most widely used regulating organs include a spring-balance type oscillator and an anchor escapement. These devices, widely described in the technical literature, most often have oscillation frequencies of 4 or 5 Hz, ie 28,800 or 36,000 vibrations / hour.

There are known mechanical chronographs higher frequency, e.g. pulsing 360'000 / hour, and capable of measuring the 100 ^th of a second. The patent application US20110164477 describes a wristwatch with a first low frequency regulating device for counting the time, and a second regulating member to 360'000 oscillations per hour for the chronograph ^1/100 second. The applicant's caliber 360, then the Carrera Mikrograph watch presented by the applicant, exploit this construction. The 'Mikrotimer 1000' developed by the applicant manages to mechanically measure the ^1000th of a second thanks to an oscillator comprising a very high stiffness balance spring and a regulating member without balance, with low moment of inertia, giving rise to 3,600 '000 vibrations per hour.

We do not know, however, faster oscillators and mechanical escapements, allowing an even higher resolution. There is therefore a need to measure timed times with a resolution equal to or greater than known resolutions.

It has been observed in the context of the invention that the conventional spiral regulator is no longer suitable for constituting standards useful for measuring precise time or as soon as frequencies of the order of 500 to 800 are exceeded. Hz because it loses precision and consumes too much energy. Moreover, its overall inertia and its dynamic behavior are not suitable for high frequency oscillation.

One of the difficulties encountered in the production of increasingly rapid regulating organs is linked to the increase in the energy required for their operation. In conventional type exhausts, in fact, the escape wheel as well as all the gear train which drives it are subjected to an alternation of acceleration phases and rest phases, which causes a high loss of energy, which greatly reduces the power reserve of the watch. There is therefore a need for a regulating member for watches capable of maintaining isochronous oscillations faster than the known devices, with better energy efficiency.

Regulating members based for example on tuning forks are already known in the state of the art. The website “http://www.electric-clocks.nl/clocks/animations/AnimationT-Breguet.htm” describes a clock possibly developed by Louis François Clément Breguet, in which one of the branches of a tuning fork is excited by the anchor of an escapement.

où :

• f est la fréquence fondamentale de vibration du diapason en hertz ;
• R est le rayon des branches, en mètres ;
• l est la longueur des branches, en mètres ;
• E est le module d'Young du matériau dont est fait le diapason en pascals ;
• ρ est la masse volumique du matériau dont est fait le diapason, en kg/m2 .

The oscillation frequency f of a tuning fork with cylindrical branches varies according to the formula: $$f=\frac{R}{l^2}\sqrt{\frac{\mathit{\pi E}}{\rho }}$$

or :

• f is the fundamental vibrating frequency of the tuning fork in hertz;
• R is the radius of the branches, in meters;
• l is the length of the branches, in meters;
• E is the Young's modulus of the material of which the pascal tuning fork is made;
• ρ is the density of the material the tuning fork is made of, in kg / m2.

Therefore, the oscillation frequency decreases rapidly as the branches lengthen. Simple calculations show, however, that long lengths are necessary in order to obtain oscillation frequencies compatible with the operation of movements. mechanical. For example, the tuning fork described in the aforementioned website vibrates at 100Hz, which is already considered a very high frequency in mechanical watchmaking. This frequency, however, requires a very large tuning fork, which can barely be integrated into a pendulum, but would be impossible to place in a wristwatch. A shorter tuning fork would produce an unnecessarily high frequency, causing excessively rapid oscillation of the anchor, anchor wheel and movement, and therefore significant energy loss, reduced power reserve and excessive wear. pieces.

For all these reasons, the use of tuning forks in mechanical watchmaking has remained essentially confined to clocks, or to electric watches in which the high frequency of oscillation of the tuning forks can be useful. On the other hand, the use of tuning forks in movements for mechanical watches is generally considered inappropriate.

CH442153 or similar GB1138818 describe a timepiece movement comprising a tuning fork coupled or mechanically connected to an anchor mounted on an oscillating blade. This system makes it possible to vibrate the blade and therefore the anchor at a frequency lower than that of the tuning fork, which can therefore be more easily miniaturized. However, this document does not indicate whether the minimum dimensions that can be obtained are compatible with a wristwatch.

FR1505656 describes a movement for a pendulum comprising an anchor fitted with paddles and which oscillates perpendicular to the plane of the escape wheel.

US6775582 describes a movement with an elastic connection of the escape wheel.

Brief summary of the invention

An object of the present invention is to provide an escapement making it possible to maintain and count very high frequency oscillations as well as a clockwork mechanism using such an escapement. According to the invention, these aims are achieved in particular by means of the subject of the appended claims.

In particular, these objects are achieved by means of a regulating member as defined in independent claim 1. Preferred embodiments are defined in the dependent claims.

Thus, the oscillation frequency of this regulating member depends not only on the characteristics of the vibrating oscillator (blade or tuning fork), but also on the flexibility of the anchor beam.

The coupling between the vibrating oscillator and the flexible beam of the anchor makes it possible to reduce the oscillation frequency of the escapement. Thus, even a vibrating blade or a tuning fork with dimensions compatible with a wristwatch can be used in the regulating organ.

Moreover, the vibrating oscillator is intended for a mechanical chronograph. In a mechanical chronograph, a high oscillation frequency is useful as it allows times to be counted with high resolution. On the other hand, chronographs are generally used to measure relatively short durations, so that the loss of power reserve and The wear of the movement that a high frequency could cause is less of a problem.

In a preferred embodiment, the elastic blade is connected to the flexible beam of the anchor by a mechanical connector, which may include an arm. The coupling between the elastic blade and the flexible beam of the anchor is thus made through an arm which has its own flexibility, and which thus contributes to reducing or determining the frequency of oscillation of the system.

The anchors usually used in conventional watch escapements have two arms which carry the paddles and are integral with a beam, sometimes called a rod. The oscillation frequency is determined above all by the sprung balance assembly and an attempt is made to avoid any disturbance caused by the anchor on this frequency. For this reason, the rod of conventional escapement anchors is as rigid as possible, taking into account the constraints of mass (which must be reduced to reduce losses) and the minimum length of the anchor. No particular measure is taken to increase the flexibility of the anchor rod, so that its influence can be completely neglected when calculating the oscillation frequency of the balance-spring-escapement assembly.

According to the invention, the flexibility of the beam (or rod) of the anchor is used, instead of being reduced until it becomes negligible. Therefore, voluntary measures are taken to increase the flexibility of this beam.

In one embodiment, the section of the beam, and in particular its width (in the plane of the escape wheel), is reduced compared to a conventional anchor, in order to reduce its rigidity at constant length.

In order to avoid a too small section, and a risk of fragility, the length of the flexible beam is increased, which gives it a deliberately increased flexibility. Advantageously, the beam is therefore longer than in a classic Swiss lever escapement anchor. In one embodiment, the length of the flexible beam is at least twice as great as the maximum width of the anchor at the arms.

By combining these two measurements, we therefore obtain an anchor fitted with a beam in which the ratio between the width and the length is markedly smaller than in conventional anchors. In one embodiment, the maximum width of the flexible beam is less than one twentieth of its length, advantageously less than one thirtieth of its length.

These various measures make it possible to produce an anchor fitted with a flexible beam, that is to say a beam whose flexibility contributes significantly to the oscillation frequency of the escape wheel. In an advantageous embodiment, the anchor contributes for at least 1%, advantageously for at least 5%, for example for at least 10%, to the frequency of oscillation at the level of the escape wheel; that is, using a hypothetical perfectly rigid beam, instead of this flexible beam, would produce a regulating member oscillating at a frequency varying by at least 1%, preferably 5%, for example 10 %, compared to the oscillation frequency obtained by this flexible beam.

All these measurements therefore make it possible to produce a regulating organ for a mechanical chronograph based on a tuning fork, or on a vibrating blade, and therefore to overcome both the known problems of balance springs and the limitations of tuning forks.

Brief description of the figures

• La figure 1 illustre un mouvement d'horlogerie comprenant un organe réglant selon un aspect de l'invention.
• La figure 2 montre l'organe réglant de l'invention dans le mouvement de la figure 1, et
• La figure 3 représente le même organe réglant en vue explosée.
• Les figures 4a-4e montrent des phases de l'action de l'échappement de l'organe réglant de l'invention.
• La figure 5 illustre schématiquement une chaîne de transmission comprenant un barillet, un rouage multiplicateur, et un organe réglant selon un aspect de l'invention.
• La figure 6 montre la position du point de début de l'impulsion sur la surface d'impulsion de l'ancre de l'organe réglant de l'invention.
• La figure 7 montre la distance angulaire θ parcourue par la roue d'échappement en fonction du temps.

Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which:

• The figure 1 illustrates a timepiece movement comprising a regulating member according to one aspect of the invention.
• The figure 2 shows the regulating organ of the invention in the movement of the figure 1 , and
• The figure 3 represents the same regulating organ in exploded view.
• The figures 4a-4e show phases of the action of the exhaust of the regulating member of the invention.
• The figure 5 schematically illustrates a transmission chain comprising a barrel, a multiplier gear, and an adjusting member according to one aspect of the invention.
• The figure 6 shows the position of the start point of the pulse on the pulse surface of the anchor of the regulating member of the invention.
• The figure 7 shows the angular distance θ traveled by the escape wheel as a function of time.

Example (s) of embodiment of the invention

An embodiment of the regulating member of the invention is illustrated, in a simplified manner, on the figures 1 and 2 . In this example, the movement comprises a dual chain with a first regulating member, a first gear train and a first barrel (not shown) intended for measuring the current time, and a second regulating member, a second gear train and a second barrel. 32 intended for chronography. The oscillation frequency of the second regulating organ is greater than the oscillation frequency of the first regulating organ, in order to guarantee a necessary and sufficient power reserve for the chain dedicated to the display of the hour, and a very fine resolution for the measurement of durations by the chronograph.

The regulating organ of the chronograph comprises an escape wheel 60 with a predetermined number of protruding teeth having a precise geometry 63, preferably more than 25 teeth, for example 40 teeth. The high number of teeth reduces the pitch between the teeth and thus makes it possible to reduce the angular distance traveled by the escape wheel 60 at each alternation, thus reducing the amount of energy required for each alternation, and to increase the frequency. of oscillation.

This geometry and this number of teeth make it possible to quickly accelerate the anchor wheel and therefore to communicate energy as frequently as possible to the regulating member. Instead of completely stopping the anchor wheel at each cycle, this geometry slows it down at the end of the pulse. The cycle requires a very short pulse angle and as such allows a large number of teeth. The duration of a cycle is very short and it is during this period that the wheel must be accelerated to create sufficient kinetic energy. This escapement is therefore characterized by very high accelerations. The beam oscillator thus produced consumes significantly less energy than a conventional spiral oscillator, typically at least two times less than a conventional oscillator.

The anchor 80 of the chronograph comprises two arms intended to engage with the teeth of the escape wheel 60, secured to a flexible beam, also called a rod, 90. The length of the flexible beam 90, as well as its section and the material chosen gives it a voluntary flexibility; advantageously, the beam is therefore longer than in a conventional Swiss lever escapement anchor. The anchor therefore itself constitutes an oscillating element. The voluntary oscillations of the flexible beam (or rod) determine the resonant frequency of the coupled oscillator system consisting of the anchor and the vibrating blade 100.

The anchor pivots and deforms voluntarily at each alternation around the axis 91, which may be provided with a bearing of a ball or stone bearing.

The anchor is preferably devoid of paddles, in view of the speed of rotation of the escape wheel and the quantity of energy transmitted at each pulse; the production of sapphire or ceramic pallets would be complex and would considerably weigh down the anchor. Instead, the fork includes notches (or projections) 83a-83b not very prominent, with precise geometry, allowing the anchor to disengage from the teeth of the escape wheel with a rotation of very low amplitude. In an alternative, however, the rest surfaces 83a-83b could be made by stone or ceramic pallets. According to one characteristic of the invention, the escapement thus comprises an anchor 80 which oscillates around the point of articulation 93 with a very low oscillation angle, of the order of 4-5 ° for example. The cycle thus generated is different from the cycle of a conventional Swiss lever escapement.

The anchor 80 in this example does not include either stinger or peg. The articulation 93 at the end of the anchor 80 connects the anchor in an articulated manner to an arm 95. The other end of the arm 95 is connected to the free end of a vibrating blade 100. In this example no Limitingly, the arm 95 is mounted almost perpendicular to the vibrating blade 100, so that the transverse vibrations of the vibrating blade 100 are transmitted to the arm 95 and to the flexible beam 90 of the anchor. The axis of rotation 91 of the anchor being fixed, the arm 95 and the flexible beam 90 bend or unfold around the articulation 93 at each alternation.

Non-perpendicular assemblies can also be considered. Furthermore, it is also possible to produce systems in which the vibrating blade 100, the arm 95 and / or the anchor extend in planes different from each other.

The first end 103 of the vibrating blade is fixed relative to the plate. In this example, the first fixed end of the vibrating blade 100 is screwed onto the plate by means of the screw 101, other fixing means can be provided. A device 102 allows the assembly to be tuned by generating a preload: in the embodiment illustrated, this device comprises an eccentric 102 also screwed onto the plate and which can be rotated to apply a preload force to the vibrating blade 100; by turning this eccentric, the stress force applied to the vibrating blade is modified, and the resonant frequency of the vibrating blade and / or its coupling with the arm 95 is modified.

The vibrations of the free end of the vibrating blade 100 are transmitted to the anchor 90 through the arm 95. In one embodiment, the connection between the vibrating blade 100 and the arm 95 constitutes a single pivot and a slide. simple, allowing possible rotation and sliding between the two elements; the vibrating blade 100 fits into the arm. Any connection allowing the desired relative movement between the vibrating blade and the arm or coupler can be used, so as to avoid bracing of the arm 95 or of the vibrating blade 100 due to stresses exerted on this connection.

The beam 90 of the anchor thus acts as an exciter, the arm 95 constitutes a connecting beam, or connector, to transmit this excitation to the blade 100 (or oscillator) and make it vibrate or oscillate around its point of rest. Other types of exciters, including a magnetic exciter exerting a time varying magnetic field, can be used to vibrate the vibrating plate 100.

The escape wheel 60 is driven by a source of mechanical energy, for example one or more barrels 32 shown schematically on the figure. figure 6 , by means of a multiplier gear 35. The surfaces 81a and 81b of the anchor 80 alternately receive a mechanical pulse from the teeth 63 of the escape wheel 60, thus determining isochronous oscillations of the vibrating blade 100 connected to the anchor 80. The escape wheel 60 advances by one tooth at each alternation of said oscillations.

The mechanical power available at the escape wheel 60 is not constant but, in a known manner, decreases with the rate of the watch. From a maximum value, corresponding to the barrel completely reassembled, the power is gradually reduced during the relaxation of the barrel. Consequently, the amount of energy transmitted to the anchor 80 with each impulse given by the anchor wheel decreases with the load of the barrel.

In order to maintain a constant amplitude of the oscillations of the vibrating blade 100, and therefore an isochronous operation, the movement comprises means to guarantee that the moment transmitted to the anchor at each pulse is substantially constant, whatever the load on the barrel, at least during an operating range of the barrel sufficient to measure the times for which the chronograph is designed.

In a first embodiment, the barrel is modified so as to deliver a constant torque. For example, the barrel may include means for limiting the range of use in an area in which the torque supplied is substantially constant, by artificially reducing the running time of the chronograph. A barrel that can theoretically perform 7 to 10 revolutions in order to ensure a large power reserve can thus be limited and prevented from relaxing beyond one revolution, or less than one revolution, in order to guarantee that within this authorized range the torque supplied is as constant as possible.

In a second embodiment, which can also be combined with the first embodiment above, the barrel may be associated with a rocket or with another equivalent element to regulate the torque transmitted to the gear train 35.

In a third embodiment, the escape wheel 60 and / or the fork of the anchor 80 are modified in their geometry so as to transmit to the anchor a moment of impulse which is substantially independent of the engine torque transmitted to the escape wheel by the gear train 35. The geometry of the anchor receiving tooth is calculated so that a variation in torque at the anchor wheel will cause a variation in speed and therefore a linear contact zone between a point of contact at maximum speed and a point of contact at minimum speed. Whatever the point of contact, the moment will be constant by geometric variation of the lever arm. This third embodiment can be combined with the first and / or the second embodiment above.

The figures 4a-4e show phases of the action of the escapement of the regulating member according to this third embodiment of the invention. The figure 4a corresponds to the end of the fall, and to the start of the impulse on the exit surface 81b of the anchor 80. The rotation of the escape wheel 60 continues until the tip of the tooth 63 in contact with the anchor not butting against the rest notch 83b, as shown in the figure 4b . In this rest position on the outlet, the rotation of the escape wheel 60 is interrupted by the notch 83b on the fork of the anchor 80.

The oscillation of the anchor 80 under the effect of the vibrations of the vibrating blade 100 leads to the release of the tooth 63 and to the release of the escape wheel 60. A fall phase follows, until at the moment, visible on the figure 4c , where another tooth 63 of the wheel 60 contacts the other impulse surface 81a of the input arm of the anchor 80.

The rotation of the wheel 60 continues during the pulse phase on the input pulse surface 81a, until the tooth 63 reaches the rest notch 83a, as shown in the figure. figure 4d . This rest phase lasts until the moment of release, visible on the figure 4e , which gives rise to a new phase of fall and the start of another cycle.

Thus, in the escapement according to the invention, the pulse phases precede rest phases, while in most escapements used in wristwatches, the rest phases are followed by impulse phases, and impulse phases precede falls.

According to a preferred embodiment of the invention, the point of first contact between a tooth 26 and an impulse surface 81a-b of the anchor 80 is not fixed, but varies according to the speed of rotation of the escape wheel 60, and therefore the power transmitted by the cog. This aspect is illustrated on figure 6 . When barrel 32 is fully cocked, contact between tooth 63 and the impulse surface occurs at point 86a. With reduced power, acceleration of escape wheel 60 is limited, fall time increases, and contact occurs at point 81b, below. The displacement of this point of contact has the effect of modifying both the moment of impulse transmitted to the anchor 80, and / or the duration during which a moment is transmitted. Advantageously, the moment of impulse transmitted to the anchor is thus substantially independent of the speed of rotation of the escape wheel. A rapidly rotating escape wheel exerts a large force on the anchor 80 during the impulse, but at a point 86a close to the center of rotation of the anchor. An escape wheel driven by a less tensioned barrel reaches the anchor with less energy, but exerts the impulse force at a point farther from the center of rotation of the anchor. This results in an impulse moment transmitted to the anchor which is substantially constant.

The shape of the impulse surfaces 81a and 81b is optimized to ensure this constant impulse moment. In one embodiment, these pulse surfaces are curved, eg cycloid, preferably and eg brachistochrone. In another less optimal but simpler embodiment, the impulse surfaces are formed by straight line segments.

According to an important aspect of the invention, if the power available at the exhaust is insufficient, for example when the barrel is insufficiently armed, the release of the tooth 63 can take place before that it does not reach the notch of rest. In this case, the pulse phase is followed by a drop phase without stopping the escape wheel 60. During the next alternation, the escape wheel does not start from a rest condition, but already has a non-zero speed of rotation, and will be able to reach the rest notch (of the other arm of the anchor) despite the reduced available power, or at least to come closer to it. It is also possible that the very slow escape wheel does not come up against the rest notch until after a greater number of alternations, for example after three, four or more alternations. This characteristic, obtained in particular thanks to the not very prominent notches 83a-83b and to the geometer of the teeth 63, avoids completely stopping an escape wheel which has too little energy, and allows it to continue its acceleration during several successive alternations. .

The regulating member of the invention therefore comprises, in addition to the normal operating regime, with a rest phase for each alternation, an operating regime at reduced power, in which there is a rest phase every two, three or N alternations. In the reduced power mode, the operation of the regulating organ remains regular.

The figure 7 shows the angular distance θ traveled by the escape wheel 60 as a function of time. Line 200 shows the "ideal"rate; the escape wheel rotates at a constant speed. Curve 201 shows a curve corresponding to a conventional escapement, and to the escapement of the invention in its normal operating regime, in which the escape wheel is stopped at each alternation by the anchor, then accelerates again to 'to the next rest point during the next alternation. Curve 202 shows the angular distance traveled by the escape wheel of the invention in an operating speed at reduced power; during certain cycles, the anchor releases the escape wheel before stopping it, which allows the wheel to continue its acceleration during one or more successive alternations.

It has been found that the excitation of the oscillations of the vibrating blade 100 is better when the beam 90 of the anchor is itself flexible, and has a mass concentrated at its end. The flexibility of the beam makes it possible to transmit vibratory energy to the blade 100 without stopping the oscillation. In the example shown in figure 1 the mass is constituted by the hinge joint 93 itself. The connection between the flexible beam 90 of the anchor and the vibrating blade 100 is provided by an arm (or connector) 95. This arrangement therefore constitutes a system of oscillators coupled between the vibrating blade 100 and the flexible beam 90 of the anchor. It is also possible to provide an arm 95 (or connector) provided with a certain flexibility to allow it to oscillate. In this case, the arrangement therefore constitutes a system with three oscillators 100, 95, 90 coupled. The small mass can also constitute an additional tuning device. This device can for example be peelable or automatically ablated by means of a laser (automatic tuning, etc.).

It is well understood that the inertia of the anchor 80 and of the arm 95, and the coupling between the vibrations of the blade 100 and those of the flexible beam 90 modify the dynamics of the compound system. The natural frequencies of oscillation are generally not calculable with analytical methods, but can be obtained by known numerical simulation methods and also depend on the prestress applied to the blade 100. We can obtain oscillation frequencies of 1 kHz or higher.

In a variant, the anchor 80, the flexible beam 90 of the anchor, the arm 95 and the blade 100 are made in one piece. In this variant, the system can be completely flexible and devoid of joints.

The anchor 80, the flexible beam 90 of the anchor and the arm 95 and / or the blade 100 can be produced by micromachining processes, for example from a silicon wafer by an ionic etching process. reactive (DRIE) or by any other suitable process. Silicon can be coated a layer of silicon oxide to compensate for the influence of temperature.

In a variant, the anchor 80, the flexible beam 90 of the anchor and the arm 95 and / or the blade 100 can be made of metal, preferably a metal whose elastic and dimensional qualities do not depend on the temperature, such as than the elinvar.

The present invention also relates to a method for adjusting the oscillation frequency of a regulating member as described above. Several adjustment methods can be implemented independently of each other, or combined with each other.

As mentioned above, by turning the eccentric 102 near the fixed end 103 of the vibrating blade 100, the stress force applied to this blade is modified, which makes it possible to modify the frequency of the system.

The oscillation frequency can also be adjusted by varying the length of the vibrating portion of the flexible blade 100, for example by varying the embedding depth of the flexible blade. A micrometric screw can be provided for this purpose.

The oscillation frequency can also be modified by modifying the mass of the oscillating blade, or preferably a mass along or at the end of the anchor, for example the mass 93 forming the articulation with the arm 95. The variation in mass can for example be obtained by laser micromachining of mass 93 to correct the resonant frequency of the oscillating member.

External elements, for example removable or movable masses, can be added to or moved along vibrating mass 100, arm 95 and / or anchor 80 to change the frequency. External magnets can also be moved to exert a controlled influence on the vibrating blade 100.

According to another aspect of the invention, the escape wheel 60 is elastically coupled to the barrel or to the energy source 32. In the embodiment illustrated in FIG. figure 1 , a spiral spring 65 is interposed between the escape wheel 60 and the pinion 37 forming part of the gear train and coaxial with the escape wheel. This spiral spring stores the energy transmitted by the barrel through the gear train even when the escape wheel is blocked by the anchor and it cannot turn; as soon as the escape wheel is released following an oscillation of the anchor, the energy stored by the balance spring 65 is almost instantaneously released and transmitted to the escape wheel 60 which thus accelerates immediately. In addition, this acceleration is not slowed down by the inertia of the cog. This device makes it possible to overcome the inertia of the cog train, a major obstacle to the great accelerations of the escape wheel. The acceleration of the wheel 60 is limited essentially by its own inertia.

The escape wheel 60 will preferably be made so as to reduce its moment of inertia. It is preferably made of steel or of a light material, for example of silicon, of an Ni-P alloy, or of titanium, or of an alloy containing titanium.

The hairspring 65 therefore tightens during each resting phase of the anchor 80, then suddenly relaxes during release. It therefore oscillates at each alternation, like a balance spring in a conventional regulating organ. However, unlike a conventional regulating member, this hairspring does not directly determine the cycles of the escapement which are here determined by the vibrating blade. This spring is calculated specifically according to the mechanical power available at the anchor wheel, the inertias present and the speeds required on the anchor wheel.

The hairspring 65 also makes it possible to damp the shocks associated with the alternation between pulse phases and rest phases. This way, even if the rotation escape wheel is jerky, gear 35 and barrel 32 rotate with approximately constant speed, and fuel efficiency is improved.

An elastic coupling between the escape wheel and the gear train can also be obtained by means of an elastic element other than a spiral spring, for example another type of spring. Furthermore, an elastic coupling could also be provided at another location in the gear train between the barrel and the escape wheel, for example upstream of the pinion 37 on the escape shaft.

The illustrated adjustment member oscillates at a high frequency (preferably greater than 50Hz, typically greater than 500Hz, for example 1000Hz) therefore requires power which results, as with any chronograph, in a limited power reserve. Since the primary objective is to produce a precise instrument, care will be taken to guarantee a power reserve adapted to the duration of the time interval during which we are able to guarantee the target decimal chronometrically. This regulating member is therefore above all intended to regulate a chronograph used for limited periods, for example periods of less than a few hours, typically periods of a few minutes or corresponding for example to the typical duration of a sports event. Tests and simulations have shown that the use of a vibrating blade at 1000 Hz associated with the escapement of the invention makes it possible to reach or exceed the power reserve of a 500 Hz chronograph based on a hairspring, this which shows that at constant available energy, the efficiency, in terms of energy spent by alternation, is at least twice as high. The high frequency regulating organ is thus stopped most of the time, except when the chronograph is in use. In order to ensure instantaneous start-up of the regulating member, a launcher (not shown) is advantageously provided to set the vibrating blade into vibration when the user presses the START key of the chronograph. In one embodiment, this launcher acts by applying a pulse directly to the vibrating blade. In another embodiment, the launcher acts by applying a brief pulse to mass 93 at the joint between the arm. 95 and the anchor 80, so as to constrain this articulation and thus to exert a traction or a push on the free end of the vibrating blade which thus begins to oscillate. The same launcher can be used when the user presses the STOP key to block the regulating member, for example by pressing the joint 93 thus preventing the anchor 80 from oscillating.

The movement advantageously comprises openings making it possible to see the vibrating blade 100, the arm 95 and / or the anchor 90. Advantageously, the movement also makes it possible to see the hairspring 65. The movement can be integrated into a watch which makes it possible to see the through the dial one or more of the elements 90, 95, 100 and / or 65. Such an opening through the movement and the dial also makes it possible to hear the very characteristic noise of the oscillations of the regulating organ, for example the noise created by oscillations between 500 and 2000 Hz.

Reference numbers used in figures

32

barrel

35

cog

37

Pinion on the axle of the escape wheel

60

escape wheel

63

escape wheel tooth

65

elastic coupling, hairspring

80

anchor

81a, b

impulse surfaces

83a, b

rest stops

86a, b

pulse start point

90

flexible anchor beam (rod)

91

anchor axis

93

anchor joint

95

arms

100

vibrating blade

101

attachment point of the vibrating blade

102

eccentric

103

fixed end of the vibrating blade

Claims (17)

1. Regulating member for a mechanical chronograph movement comprising a vibrating oscillator (100) including a tuning-fork or a vibrating blade (100) mechanically connected to an anchor (80) having impulse surfaces (81a, 81b) alternately receiving a mechanical impulse from teeth (63) of an escapement wheel (60), so as to maintain isochronous oscillations of said vibrating oscillator, and to advance said escapement wheel (60) by one tooth with each alternation of said oscillations, a barrel (32) driving said escapement wheel through a gear (35),
   said vibrating oscillator (100) comprising an end (103) fixed with respect to a plate and a free end,
   the anchor (80) comprising a flexible beam (90) having a first end and a second end, and two arms integral with said first end of said flexible beam (90),
   characterized in that
   the free end of said vibrating oscillator (100) is connected to the second end of said flexible beam (90) so that the vibrations of the free end of the vibrating oscillator (100) are transmitted through this connection to the flexible beam (90) and so that the vibrations of the flexible beam (90) are transmitted through this connection to the vibrating oscillator (100).
2. Regulating member according to claim 1, wherein said flexible beam (90) comprises a concentrated mass at its second end.
3. Regulating member according to one of claims 1 or 2, wherein said vibrating oscillator (100) comprises an elastic blade attached to one end.
4. Regulating member according to claim 3, comprising an arm (95) as a mechanical connector for connecting said elastic blade to the flexible beam (90) of said anchor.
5. Regulating member according to claim 4, wherein said arm (95) is connected to the flexible beam (90) of the anchor by a joint.
6. Regulating member according to one of claims 1 to 5, wherein the length of the flexible beam is at least twice as long as the maximum width of the anchor at said arms.
7. Regulating member according to one of claims 1 to 6, wherein the ratio of the width of the beam to its length is less than 1/20.
8. Regulating member according to claims 1 to 6 in which a flexibility of the anchor contributes at least 1 %, advantageously at least 5 %, for example at least 10 %, to the frequency of oscillation at the escapement wheel, i.e. the use of a hypothetical fully rigid beam, instead of said flexible beam, would produce a regulating member oscillating at a frequency varying by at least 1%, preferably 5%, e.g. 10%, relative to the frequency of oscillation obtained by said flexible beam.
9. Regulating member according to one of claims 4 to 8, wherein said anchor (80), said flexible beam (90) of the anchor, said arm (95) and said elastic blade (100) are made in one piece.
10. Regulating member according to one of claims 4 to 9, wherein said anchor (80), said flexible beam (90) and said arm (95) are made from a single silicon wafer.
11. Regulating member according to one of claims 1 to 10, wherein said elastic blade (100) is made of elinvar.
12. Regulating member according to any one of claims 1 to 11, wherein said pulse surfaces (81a, 81b) are curved.
13. Regulating member according to any one of claims 1 to 11, wherein said pulse surfaces (81a, 81b) are straight.
14. Regulating member according to any one of claims 1 to 13, wherein said escapement wheel has more than 25 teeth.
15. Regulating member according to any one of claims 1 to 14, wherein said isochronous oscillations have a frequency of not less than 1 kHz.
16. Regulating member according to claim 1 to 15, wherein the point of first contact between the teeth (63) and the pulse surfaces (81a, 81b) moves along the pulse surface in accordance with the power of the barrel (32).
17. Chronograph comprising a regulating member according to one of claims 1 to 16.

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