EP3479175A1

EP3479175A1 - Mechanical clock movement

Info

Publication number: EP3479175A1
Application number: EP17733911.6A
Authority: EP
Inventors: Nicolas Dehon
Original assignee: Patek Philippe SA Geneve
Current assignee: Patek Philippe SA Geneve
Priority date: 2016-06-29
Filing date: 2017-06-21
Publication date: 2019-05-08
Anticipated expiration: 2037-06-21
Also published as: WO2018002778A1; EP3479175B1

Abstract

The invention proposes a clock movement comprising a rotary oscillator (4), a rotary impulse arm (12) for imparting pulses of mechanical energy to the oscillator (4), an energy source (1) and a transmission device (1 – 3) connecting the energy source (1) to the impulse arm (12), the transmission device (1 – 3) comprising a constant-force device (10) for periodically storing a quantity of energy to be supplied to the impulse arm (12). The said amount of energy, the geometry of the impulse arm (12) and the moments of inertia of the impulse arm (12) and of the oscillator (4) are chosen so that each time the impulse arm (12) imparts an impulse to the oscillator (4), the following relationship (I) is more or less satisfied, where I1 is the moment of inertia of the impulse arm (12), I2 is the moment of inertia of the oscillator (4), ω1i is the angular velocity of the impulse arm (12) just prior to the impulse it imparts to the oscillator (4), ω2i is the angular velocity of the oscillator (4) just prior to the said impulse, d1 is the lever arm of the impulse arm (12) and d2 is the lever arm of the oscillator (4). The invention also proposes a clock movement of the same type with an impulse arm that moves linearly and methods for achieving these movements.

Description

Mechanical watch movement

The present invention relates to a mechanical clockwork movement. A traditional mechanical watchmaking movement comprises an energy source, such as a barrel, a finishing gear driven by the power source, an escapement driven by the finishing gear and an oscillator whose oscillations are maintained by the 'exhaust. The oscillator (or regulator) is generally of the spiral balance type. The exhaust generally comprises an escape wheel (coaxial wheel and pinion and solidarity) and an anchor. The pinion of the escapement engages with the last wheel of the finishing train while the wheel of the escapement mobile cooperates with the anchor, which communicates pulses of mechanical energy to the oscillator.

Some movements also include, in the work train between the energy source and the exhaust, a so-called "constant force" device, that is to say a device comprising an intermediate spring periodically armed with the same quantity by the source of energy and supplying its energy to the exhaust. Such a constant-force device makes it possible to make oscillations of the oscillator independent of the state of winding of the energy source.

Patent applications WO 99/64936, WO 2009/1 18310 and CH 705674 also disclose an escapement comprising a bistable blade armed by an armature rocker actuated alternately by two escape wheels. A trigger rocker secured to the region of the midpoint of the bistable blade imparts pulses of mechanical energy to the oscillator during changes in state of the bistable blade. The bistable blade is a "constant force" device that periodically supplies the same amount of energy to the oscillator via the trigger rocker. In the present invention, the member that communicates the pulses of mechanical energy to the oscillator, whether in the form of a trigger rocker, an anchor or the like, is called "striker". The performance of a mechanical watch movement is low. Indeed, the escapement transmits to the oscillator only a small part of the energy it receives. One of the causes of the observed energy losses are the friction between the different parts. In particular, at each pulse imparted by the striker to the oscillator, the striker accompanies (remains in contact with) the oscillator on a pulse angle which is generally between 12 ° and 20 °. In practice, one can even observe a succession of small shocks during the pulse, especially when the frequency of the oscillator is high. Such a chaotic transmission of energy between the striker and the oscillator is an additional obstacle to obtaining a good performance.

The present invention aims at providing a clockwork movement with improved efficiency.

To this end, there is provided a clockwork movement comprising a rotary oscillator around a first axis, a rotary firing pin around a second axis for communicating pulses of mechanical energy to the oscillator, a source of energy and a transmission device connecting the energy source to the striker, the transmission device comprising a constant force device for periodically storing a quantity of energy to be supplied to the striker, characterized in that said quantity of energy, the geometry of the striker and the moments of inertia of the striker and the oscillator are chosen so that at each pulse imparted to the oscillator by the striker the following relation is substantially satisfied:

where h is the moment of inertia of the striker with respect to the second axis, h is the moment of inertia of the oscillator relative to the first axis, ω-π is the angular velocity of the striker just before the impulse gives to the oscillator, ω is the angular velocity of the oscillator just before said pulse, di is the lever arm of the firing pin and d2 is the lever arm of the oscillator.

Thanks to the relationship between the speeds expressed above, the striker transmits all its kinetic energy to the oscillator in a single shock and its velocity becomes zero immediately after the shock, so that the phenomenon of accompaniment between the striker and the oscillator and the energy losses it causes do not exist in the present invention.

According to another embodiment, the present invention proposes a clockwork movement comprising a rotary oscillator about an axis, a linear motion firing pin for communicating pulses of mechanical energy to the oscillator, a source of energy and a transmission device connecting the energy source to the striker, the transmission device comprising a constant force device for periodically storing a quantity of energy to be supplied to the striker, characterized in that said quantity of energy, the geometry and the mass of the firing pin and the moment of inertia of the oscillator are chosen so that at each pulse imparted to the oscillator by the striker the following relation is substantially satisfied:

_ 2 ^■ I ₂ ^■ d ₂

l ₂ - m ₁ - d {

where mi is the mass of the striker, I2 is the moment of inertia of the oscillator with respect to said axis, seen is the linear speed of the striker just before the impulse which it gives to the oscillator, ω is the angular velocity of the oscillator just before said pulse and d2 is the lever arm of the oscillator.

The present invention also proposes a method for producing a clockwork movement comprising a rotary oscillator around a first axis, a rotary striker around a second axis for communicating pulses of mechanical energy to the oscillator, a source of energy and a device transmission connecting the power source to the firing pin, the transmission device comprising a constant force device for periodically storing a quantity of energy to be supplied to the firing pin, the method comprising a motion design step followed by a step of manufacturing the firing pin; movement, the method being characterized in that during the design of the movement, said amount of energy, the geometry of the firing pin and the moments of inertia of the striker and the oscillator are chosen so that at each pulse imparted to the oscillator by the striker the following relation is substantially satisfied:

2 ^■ I ₂ ^■ d _x ^■ d ₂

ω 2i

where h is the moment of inertia of the striker with respect to the second axis, I2 is the moment of inertia of the oscillator relative to the first axis, ω-π is the angular velocity of the striker just before the impulse gives to the oscillator, 0021 is the angular velocity of the oscillator just before said pulse, di is the lever arm of the firing pin and d2 is the lever arm of the oscillator.

Finally, according to another embodiment, the present invention proposes a method for producing a clockwork movement comprising a rotary oscillator about an axis, a linear motion striker for communicating pulses of mechanical energy to the oscillator, a power source and a transmission device connecting the power source to the firing pin, the transmission device comprising a constant force device for periodically storing a quantity of energy to be supplied to the striker, the method comprising a step of motion design followed by a movement manufacturing step, the method being characterized in that during motion design, said amount of energy, the striker geometry and mass, and the moment of inertia of the oscillator are chosen so that at each pulse imparted to the oscillator by the striker the following relation is substantially satisfied:

_ 2 ^■ I ₂ ^■ d ₂

l ₂ - m ₁ - d {where mi is the mass of the striker, I2 is the moment of inertia of the oscillator with respect to the axis, seen is the linear velocity of the striker just before the impulse it gives to the oscillator, ω is the angular velocity of the oscillator just before said pulse and d2 is the lever arm of the oscillator.

Other features and advantages of the present invention will appear on reading the following detailed description given with reference to the accompanying drawings in which:

FIG. 1 is a block diagram of a watch movement,

FIGS. 2 to 10 show, in plan view, different operating phases of a constant force escapement and an oscillator used in the present invention;

- Figure 1 1 shows in top view an exhaust striker and a double oscillator plate used in the present invention;

- Figure 12 shows a top view of a variant of the striker used in the present invention;

- Figure 13 shows in top view another variant of the striker used in the present invention.

With reference to FIGS. 1 and 2, a mechanical clockwork according to the invention comprises a power source 1, typically constituted by one or more barrels, a finishing gear 2, an escapement 3 and an oscillator 4. The source energy 1 and the work train 2 are conventional, they will not be described. The oscillator 4 is also of conventional type. It comprises, mounted on a balance shaft 6 of axis A, a balance spring (not shown) and a double tray. The double plate comprises a large plate 7, which carries a plate pin 8, and a small plate 9.

The exhaust 3 is of the type described in the patent applications WO 99/64936, WO 2009/1 18310 and CH 705674. It thus comprises two exhaust mobiles (not shown), a bistable leaf spring 10, a flip-flop. arming 1 1 and striker or trigger rocker 12.

The two exhaust mounts each comprise a pinion which meshes with the last wheel of the work train 2 and an escape wheel provided not with teeth but with cams each terminated by a locking stop. The two escape wheels respectively cooperate and alternately with exhaust pins 13 carried by the rocker 1 1.

The armature rocker 1 1 and striker 12 pivot about the same axis B which corresponds to the midpoint of the leaf spring 10. In practice, the axis B is for example the axis of a rod driven into the armature rocker 1 1, pivoting in bearings of the frame of the movement and around which pivots the firing pin 12.

Preferably, the leaf spring 10 is integral with the striker 12 and with an outer frame (not shown) which surrounds the leaf spring 10, and consists of two elastic strips 10a, 10b each having an end joined to the firing pin 12 and another end attached to the outer frame, attached to the frame of the movement. The leaf spring 10 has two convexities of opposite directions on either side of its midpoint and can move from a first stable state to a second stable state by reversing the direction of each of the two convexities. For this purpose, the leaf spring 10 is either prestressed so as to work in buckling or preformed to, in the state of rest, already present two convexities as described in the international patent application WO 2017/032528 of the present applicant. In the first case, the outer frame is deformable to allow buckling of the leaf spring 10. In the second case, the outer frame is rigid. The rocker arm 1 1 comprises two arms 14 carrying at their ends two pins 14a, 14b engaged in eyelets (not shown) of the two resilient blades 10a, 10b respectively. A reverse configuration is of course possible where the pins 14a, 14b would be carried by the resilient blades 10a, 10b, respectively, to engage in the eyelets of the rocker 1 1. In addition, other modes of connection between the rocking lever 1 1 and the elastic blades 10a, 10b are conceivable, for example two pins at the end of each arm 14 of the rocker 1 1 pinching the blade corresponding elastic.

The striker 12 comprises a body 15 surrounding the axis B and extended on one side by a fork 16-17 and on the other side by a tail 18. The fork 16-17 fulfills the function of an anchor fork conventional, ie cooperating with the plate pin 8 to communicate pulses of mechanical energy to the oscillator 4, and comprises for this purpose a first horn 16 and a second horn 17. A dart 19 secured to the striker 12 is likely to cooperate with the small plate 9 of the oscillator 4 to prevent the reversal of the firing pin 12 in the event of impact. The tail 18 is itself designed to cooperate with first and second limiting abutments 20, 21 fixed relative to the frame of the movement, for example one-piece with the aforementioned outer frame, to limit the angular displacement of the firing pin 12.

In operation, the armature rocker 1 1, actuated by a winding cam of one of the escape wheels and acting symmetrically in the region of the two convexities of the leaf spring 10, deforms the leaf spring 10 from a first of its stable states to a metastable state close to an unstable state corresponding to a fourth mode buckling, for arming the leaf spring 10. This arming phase ends when the armature rocker 1 1 is blocked by a locking stop of the escape wheel with which it cooperates, which keeps the leaf spring 10 in its metastable state and immobilizes the two escape wheels, the work train 2 and the armature rocker 1 1 Then the striker 12 located in the region of the midpoint of the leaf spring 10 acts on the leaf spring 10 to make it exceed its unstable state and thus make it rock in its second stable state by releasing its energy. The energy enabling the firing pin 12 to deform the leaf spring 10 beyond its unstable state since its metastable state is provided by the oscillator 4, when the plate pin 8 collides with the horn 16 of the fork. This phase, which requires only a small supply of energy, can be compared to the phase of release of an anchor escapement. The expansion of the leaf spring 10, that is to say its passage from its unstable state to its second stable state, suddenly changes the inclination of the zone of the midpoint, which causes the striker 12 to pivot, which then communicates an impulse at the plateau pin 8 by its horn 17. The deformation of the leaf spring 10 from its metastable state to its second stable state under the action of the plate pin 8 and then its detent causes a rotation of the rocker d arming 1 1 which unlocks the escape wheels and causes the armature lever 1 1 in contact with the other escape wheel to start a symmetrical cycle of the previous, after the pulse given to the plate pin 8.

Figures 2 to 10 show the different operating phases of the escapement and the oscillator. In FIG. 2, the oscillator 4 is in the acceleration phase and traverses the downward sinistral angle, the striker 12 bears against the limit stop 20 and the leaf spring 10 is at the end of the weave (metastable state ). In FIG. 3, the oscillator 4 is close to its maximum speed and begins to traverse the sinister lift angle, the horn 16 of the striker 12 is struck by the plate pin 8 (release, by a single shock) and the leaf spring 10 is unlocked (between the metastable state and the unstable state). In FIG. 4, the oscillator 4 is at its maximum speed and traverses the sinister lift angle, the striker 12 strikes by its horn 17 the plate pin 8 to impart to it an impulse (by a single shock as will be explained further) while the leaf spring 10 has just switched from the unstable state to the second stable state. In FIG. 5, the oscillator 4 decelerates and traverses the ascending ascending angle, the striker 12 is in abutment against the limit stop 21 and the leaf spring 10 is at the beginning of arming (it leaves the second stable state). In FIG. 6, the rotation of the oscillator 4 reverses (maximum elongation sinister), the striker 12 bears against the limit stop 21 and the leaf spring 10 is being wound (between the second state stable and metastable state). In FIG. 7, the oscillator 4 is close to its maximum speed and begins to traverse the dextral lifting angle, the horn 17 of the striker 12 is struck by the plate pin 8 (disengagement, by a single shock) and the leaf spring 10 is unlocked (between the metastable state and the unstable state). In FIG. 8, the oscillator 4 is at its maximum speed and traverses the dextral lifting angle, the striker 12 strikes by its horn 16 the plate pin 8 to impart to it an impulse (by a single shock as will be explained further) while the leaf spring 10 has just switched from the unstable state to the first stable state. In FIG. 9, the oscillator 4 decelerates and traverses the upward dextral angle, the firing pin 12 bears against the limiting abutment 20 and the leaf spring 10 is at the beginning of arming (it leaves the first stable state) . Finally, in FIG. 10 the rotation of the oscillator 4 is reversed (maximum dextral elongation), the striker 12 bears against the limit stop 20 and the leaf spring 10 is being wound (between the first stable state and the metastable state). Then, the exhaust 3 is found in the phase illustrated in Figure 2 and the sequence of Figures 2 to 10 is repeated.

In a traditional escapement, the pulse angle, that is to say the angle traveled by the firing pin between the beginning of the pulse and the end of the pulse, is between 12 ° and 20 °. In the present invention, however, this pulse angle is very small, typically less than 1, 5 ° or even 1 °. Indeed, during the design of the movement according to the invention, the various parameters of the movement, in particular the amount of mechanical energy stored in the leaf spring 10 to each of its armatures, the geometry of the striker 12 and the moments of the inertia of the firing pin 12 and the oscillator 4 are chosen in such a way that the firing pin 12 transfers all its kinetic energy to the oscillator 4 in a single shock (FIGS. 4 and 8), the firing pin 12 having a zero speed just after the shock, the residual energy in the leaf spring 10 then bringing the striker 12 bearing against one of the limit stops 20, 21 (Figures 5 and 9).

According to the theory of elastic shocks, the kinetic moment conservation equation and the kinetic energy conservation equation can be written in the following way: for the conservation of kinetic momentum:

(1)

for the conservation of kinetic energy OR

h is the moment of inertia of the striker 12 (including all the elements which rotate with it, like the stinger 19) with respect to its axis of rotation B,

I2 is the moment of inertia of the oscillator 4 (including all the elements which rotate with it, like the balance shaft 6) with respect to its axis of rotation A,

n is the angular velocity of striker 12 just before the pulse it gives to oscillator 4,

ω-if is the angular velocity of the striker 12 just after said pulse, - or2i is the angular velocity of the oscillator 4 just before said pulse, or2f is the angular velocity of the oscillator 4 just after said pulse, di is the lever arm of the firing pin 12 (see FIG. 1 1), that is to say the distance between the axis of rotation B and the line of action of the reaction-action forces F2 and F1 exerted by the striker 12 and the plate pin 8 on the other at the moment of impact (pulse), and d2 is the lever arm of the oscillator 4 (see FIG. the distance between the axis of rotation A and the line of action of the reaction-action forces F2 and F1 exerted by the striker 12 and the plate pin 8 on the other at the moment of impact ( impulse).

The system of equations (1) - (2) can be rewritten as follows:

cu

By imposing a zero kinetic energy, therefore a zero angular velocity, of the striker 12 after the pulse (ω-if = 0), the solution of this system of equation is as follows:

In practice, the moment of inertia h of the firing pin 12 will most often be much lower than the moment of inertia I2 of the oscillator 4, the ratio I2 / I1 being typically greater than 10, or even 50 or 100, or even to 500 or even 1000. The solution of the system of equations (1) - (2) can therefore be expressed as follows:

2-d ₂

(6) Thus, by ensuring that at the moment of impact the angular velocity of striker 12 is approximately equal to 2d2 / di times the angular velocity of oscillator 4, the speed of striker 12 will be zero right after the impact, which implies that all its kinetic energy has been communicated to the oscillator 4 and that the striker 12 will not accompany the oscillator 4. This results in a significant improvement in the performance of the escapement and chronometry of the movement.

To obtain the relation (5) or (6) above, it is possible to play on the ratio of the lever arms d2 / di and / or on the speeds ω-π and ω. At a constant d2 / di ratio, the striker 12 must be accelerated relative to strikers of the state of the art in order to reach the speed of 2- (d2 / di) -ou2i at the moment of the pulse. Such an acceleration can be obtained for example:

by increasing the amount of mechanical energy stored by the leaf spring 10 at each arming (for example by increasing the buckling or the thickness of the leaf spring 10),

and / or by increasing the spacing of the horns 16, 17 of the striker 12, and / or by decreasing the moment of inertia h of the striker 12.

All of these parameters can be adjusted during motion design using simulation software.

Thus, for example, the spacing E of the horns 16, 17 (measured between the respective points of the horns 16, 17 which strike the plate pin 8 during the pulses, see FIG. 1 1) is greater than 1, 2 times, preferably 1 to 3 times, preferably 1 to 4 times, preferably 1 to 5 times, preferably 1 to 6 times, preferably 1 to 7 times, preferably 1 to 8 times, preferably 1, 9 times, more preferably 2 times, the diameter D of the plate pin 8. Such a spacing is thus greater than the spacing of 1, 06 (= 0.35 / 0.33) times the diameter of the ankle that is classically observed in the exhausts.

By "diameter of the plateau peg" is meant its diameter strictly speaking, especially when the plateau peg is semi-shaped. circular as shown, or more generally its largest dimension perpendicular to the plane which contains the axis of rotation A of the oscillator 4 and which constitutes a plane of symmetry for the plate pin 8. The plate pin 8 may have other forms than that shown, for example the shape of a finger or a portion of a finger extending radially from an annular portion mounted on the balance shaft 6.

In addition to the acceleration of the striker 12 that it allows, the large spacing E horns 16, 17 according to the invention promotes the exit of the pin 8 of the fork 16-17 after the pulse by allowing him, given the zero velocity striker 12, out of said range without touching the other horn that that has communicated the pulse. Thanks to this characteristic too, the performance of the escapement and the chronometry of the movement are improved.

According to another advantageous characteristic of the invention, visible in FIGS. 4, 8 and 11, the pulse communicated by the firing pin 12 to the oscillator 4 occurs while the plate pin 8 is on the line of the centers, that is to say, while the plate pin 8 is traversed symmetrically by the plane containing the axis of rotation A of the oscillator 4 and the axis of rotation B of the striker 12. This position of the plateau pin 8 corresponds to the equilibrium position of the oscillator 4. Communicating the impulse on the line of the centers makes it possible not to affect the isochronism of the oscillator.

However, alternatively, it is possible to choose to carry out the pulse while the plate pin 8 is situated after the line of the centers, this in order to favor the exit of the pin 8 from the fork 16-17 after the pulse. allowing him to leave the said fork without touching the other horn than the one that gave him the impulse. A pulse after the line of the centers gives delay to the movement but, thanks to the unique shock produced by the pulse in the present invention, this delay will remain constant so that it can be corrected by a simple adjustment of the inertia the balance and / or the active length of the spiral. The pairs of materials commonly used in the striker and the plate anchor exhausts, such as ruby-steel, silicon-ruby and silicon-silicon, have restitution coefficients ε of about 1. These materials therefore make it possible to obtain elastic shocks, that is to say shocks responding to equations (1) and (2) above. Nevertheless, it is found in the present invention that the relation (5) constitutes an optimum in terms of the efficiency of the escapement for a given restitution coefficient ε, even if the latter is less than 1.

Preferably, the striker 12 (or at least the fork 16-17) and the pin 8 are each made of one of the following materials: steel, preferably tempered; aluminum oxide, preferably ruby, more preferably ruby obtained by the Verneuil process; silicon, preferably monocrystalline, preferably also coated with silicon oxide; metal glass. All combinations of these materials are possible to form the couple of materials of the firing pin 12 and the peg 8.

The firing pin 12 illustrated in FIGS. 2 to 1 1 is balanced, in other words its geometry is chosen so that its center of gravity is situated on its axis of rotation B. Such a firing pin shape makes it insensitive to linear shocks received by the watch movement. Figure 12 shows a variant of the striker used in the present invention. According to this variant, the striker, designated by 12 ', is not balanced but instead has an unbalance that confers two arms 22, 23 which extend the horns 16, 17. These two arms 22, 23, located on the on the other side of the axis of rotation B with respect to the tail 18, replace said tail. They thus cooperate respectively with limiting stops 20 ', 21' to limit the angular movement of the firing pin 12 '.

The imbalance of the striker 12 'is chosen so that during shocks (pulses) communicated by the firing pin 12' to the plate pin 8, the reaction forces at the axis of rotation B are minimal, thus making it possible to optimize the transmission of energy between the striker 12 'and the oscillator 4 and thus the efficiency of the exhaust. More precisely, the imbalance of the striker 12 'is chosen so that the following relation is satisfied:

(7)

m ^ Lc or

mi is the mass of the striker 12 ',

di is the lever arm of the striker 12 ', that is to say the distance between the axis of rotation B and the line of action of the reaction-action forces F2 and F1 exerted by the striker 12' and the ankle plate 8 on top of each other at the moment of impact (impulse),

h is the moment of inertia of the striker 12 'with respect to its axis of rotation B, and

LG is the distance between the axis of rotation B of the striker 12 'and the line parallel to the line of action of the forces F2, F1 and passing through the center of gravity G of the firing pin 12'.

By choosing the imbalance of the firing pin 12 'so that the relation (7) above is satisfied, the component parallel to the forces F2, F1 of the reaction force exerted at the axis of rotation B during a pulse is nothing.

The present invention has been described above by way of example only.

It goes without saying that many modifications could be made without departing from the scope of the claimed invention. For example :

another type of constant force device that a bistable leaf spring could be used;

- The horns 16, 17 could be part of the oscillator 4 and the plate pin 8 could be part of the firing pin 12;

instead of being mounted on a physical axis 6, the oscillator 4 could be of the flexible pivot type; instead of being mounted on a physical axis, the firing pin 12 could also be of the flexible pivot type.

In addition, the present invention is not limited to a rotary striker. The firing pin can indeed be mobile in translation rather than in rotation, like the striker 12 "illustrated in FIG. 13. Such a mobile firing pin can be actuated for example by a mobile frame of the type described in the patent application WO 2013/144236.

In the case of a slider moving in translation, the system of equation (1) - (2) is replaced by the following two equations:

(V) d ₂ or

mi is the mass of the striker 12 "(including all the elements that move with it, like the sting 19),

seen is the linear speed of the striker 12 "just before the impulse it gives to the oscillator 4,

bright is the linear velocity of the striker 12 "just after said pulse, where2i is the angular velocity of the oscillator 4 just before said pulse, or2f is the angular velocity of the oscillator 4 just after said pulse, and d2 is the lever of the oscillator 4, measured as indicated above.

This system of equations can be rewritten as follows:

By imposing a zero kinetic energy, therefore a zero linear velocity, of the striker 12 "after the pulse (vif = 0), the solution of this system of equation is as follows: In practice, the moment of orbital inertia mi.d2 ² of the firing pin 12 "will most often be much lower than the moment of inertia I2 of the oscillator 4, the ratio l2 / (mrd2 ² ) typically being greater than 10, even at 50, even 100 or 500 or even 1000. The solution of the system of equations (1 ') - (2') can be expressed as follows: v _u = 2 ^■ d ₂ ^■ a) _2i (6 ')

Claims

A watch movement comprising an oscillator (4) rotatable about a first axis (A), a striker (12) rotatable about a second axis (B) for imparting pulses of mechanical energy to the oscillator (4), a power source (1) and a transmission device (1-3) connecting the power source (1) to the striker (12), the transmission device (1-3) comprising a constant force (10) for periodically storing a quantity of energy to be supplied to the striker (12), characterized in that said quantity of energy, the geometry of the striker (12) and the moments of inertia of the striker (12) and of the oscillator (4) are chosen so that at each pulse imparted to the oscillator (4) by the firing pin (12) the following relationship is substantially satisfied:

^ω ιί ^~ - dl - - dl ^ where h is the moment of inertia of the firing pin (12) relative to the second axis (B), I2 is the oscillator inertia moment (4) relative to the first axis (A), n is the angular velocity of the striker (12) just before the pulse it gives to the oscillator (4), ω is the angular velocity of the oscillator (4) just before said pulse, di is the lever arm of the firing pin (12) and d2 is the lever arm of the oscillator (4).

A watch movement comprising an oscillator (4) rotatable about an axis (A), a striker (12 ") with linear displacement for imparting pulses of mechanical energy to the oscillator (4), a source of energy (1) and a transmission device (1 -3) connecting the energy source (1) to the striker (12 "), the transmission device (1 -3) comprising a constant-force device for periodically storing a quantity of energy to be supplied to the firing pin (12"), characterized in that the said quantity of energy, the geometry and the mass of the firing pin (12 ") and the moment of inertia of the oscillator (4) are chosen so that at each pulse imparted to the oscillator (4) by the firing pin (12") the following relationship is substantially satisfied:

_ 2 ^■ I ₂ ^■ d ₂

l ₂ - m ₁ - d {

where mi is the striker mass (12 "), I2 is the moment of inertia of the oscillator (4) with respect to said axis (A), seen is the linear velocity of the striker (12") just before the impulse it gives the oscillator (4), ω is the angular velocity of the oscillator (4) just before said pulse and d2 is the lever arm of the oscillator (4).

3. Watchmaking movement according to claim 1, characterized in that the ratio I2 / I1 is greater than 10, preferably greater than 50, preferably greater than 100, preferably greater than 500, more preferably greater than 1000.

4. A clock movement according to claim 2, characterized in that the ratio 12 / (mrd2 ² ) is greater than 10, preferably greater than 50, preferably greater than 100, preferably greater than 500, more preferably greater than at 1000.

5. A watch movement according to claim 1 or 3, characterized in that the striker (12 ') has an unbalance chosen so that the following relationship is substantially satisfied: where di, h and mi are respectively the lever arm, the moment of inertia with respect to the second axis (B) and the mass of the firing pin (12 ') and LG is the distance between the second axis (B) and the right passing through the center of gravity (G) of the firing pin (12 ') and parallel to the force (F2) exerted by the firing pin (12') on the oscillator (4) at the moment of the pulse.

6. A watch movement according to claim 1, 3 or 5, characterized in that said amount of energy, the geometry of the firing pin (12) and the moments of inertia of the firing pin (12) and the oscillator (4). ) are chosen so that the pulse angle traveled by the striker (12) at each pulse imparted to the oscillator (4) is less than 1, 5 °, preferably less than 1 °.

7. A watch movement according to any one of claims 1 to 6, characterized in that the striker (12) or the oscillator (4) comprises a fork (16, 17) arranged to cooperate with an ankle (8). the oscillator (4) or striker (12) respectively, the fork comprising first and second horns (16, 17), and in that the gap (E) of the first and second horns (16, 17), measured between the respective points of the first and second horns (16, 17) which strike or are struck by the pin (8) during said pulses, is greater than 1.2 times, preferably greater than 1.3 times, preferably greater than at 1, 4, preferably greater than 1.5, preferably greater than 1.6, of preferably greater than 1, 7 times, preferably greater than 1.8 times, preferably greater than 1, 9 times, more preferably greater than 2 times, the diameter (D) of the ankle (8).

8. Timepiece according to any one of claims 1 to 7, characterized in that the firing pin (12) and the oscillator (4) are arranged so that each of said pulses is communicated to the oscillator (4) then that it is substantially in its angular position of equilibrium.

9. Timepiece according to any one of claims 1 to 7, characterized in that the firing pin (12) and the oscillator (4) are arranged so that each of said pulses is communicated to the oscillator (4) then that it is after its angular position of equilibrium.

10. Timepiece according to any one of claims 1 to 9, characterized in that the constant force device (10) comprises a bistable elastic member.

1 1. Timepiece movement according to any one of claims 1 to 10, characterized in that at least a portion (16-17) of the striker (12) and at least a portion (8) of the oscillator (4) arranged to cooperate with each other to communicate said pulses are each made of one of the following materials: steel, aluminum oxide, silicon, metal glass.

12. A method of producing a clockwork comprising an oscillator (4) rotatable about a first axis (A), a striker (12) rotatable about a second axis (B) to communicate pulses of mechanical energy to the oscillator (4), a power source (1) and a transmission device (1 -3) connecting the power source (1) to the firing pin (12), the transmission device (1 -3) comprising a constant force device (10) for periodically storing a quantity of energy to be supplied to the firing pin (12), the method comprising a step of designing the movement followed by a step of manufacturing the movement, the method being characterized in that during the design of the movement, said quantity of energy, the geometry of the striker (12) and the moments of inertia of the firing pin (12) and the oscillator (4) are chosen so that at each pulse imparted to the oscillator (4) by the firing pin (12) the following relationship is substantially satisfied:

_ 2 ^■ I ₂ ^■ d ₁ ^■ d ₂

where h is the moment of inertia of the striker (12) with respect to the second axis (B), I2 is the moment of inertia of the oscillator (4) with respect to the first axis (A), n is the angular velocity of the firing pin (12) just before the pulse it gives to the oscillator (4), ω is the angular velocity of the oscillator (4) just before said pulse, di is the lever arm of the firing pin (12) and d2 is the lever arm of the oscillator (4).

13. A method for producing a clockwork comprising an oscillator (4) rotatable about an axis (A), a striker (12 ") with linear displacement for imparting pulses of mechanical energy to the oscillator ( 4), a power source (1) and a transmission device (1 - 3) connecting the energy source (1) to the striker (12 "), the transmission device (1 -3) comprising a constant force for periodically storing a quantity of energy to be supplied to the firing pin (12 "), the method comprising a step of designing the movement followed by a step of manufacturing the movement, the method being characterized in that that during the design of the movement, said quantity of energy, the geometry and the mass of the striker (12 ") and the moment of inertia of the oscillator (4) are chosen so that at each pulse communicated to the oscillator (4) by the striker (12 ") the following relation is substantially satisfied:

_ 2 ^■ I ₂ ^■ d ₂

14. The method of claim 12, characterized in that the ratio I2 / I1 is greater than 10, preferably greater than 50, preferably greater than 100, preferably greater than 500, more preferably greater than 1000.

15. Method according to claim 13, characterized in that the ratio 12 / (m d2 ² ) is greater than 10, preferably greater than 50, preferably greater than 100, preferably greater than 500, more preferably greater than 1,000.

16. The method of claim 12 or 14, characterized in that during the design of the movement is chosen for the striker (12 ') an unbalance so that the following relationship is substantially satisfied: m ₁ ^■ L _G where di, h and mi are respectively the lever arm, the moment of inertia with respect to the second axis (B) and the mass of the striker (12 ') and LG is the distance between the second axis ( B) and the line passing through the center of gravity (G) of the striker (12 ') and parallel to the force (F2) exerted by the firing pin (12') on the oscillator (4) at the moment of the pulse.

17. The method of claim 12, 14 or 16, characterized in that during the design of the movement said amount of energy, the geometry of the striker (12) and the moments of inertia of the striker (12) and the oscillator (4) are chosen so that the pulse angle traveled by the striker (12) at each pulse imparted to the oscillator (4) is less than 1, 5 °, preferably less than 1 °.

18. Method according to any one of claims 12 to 17, characterized in that the striker (12) or the oscillator (4) comprises a fork (16, 17) arranged to cooperate with an ankle (8) of the oscillator (4) or firing pin (12) respectively, the fork comprising first and second horns (16, 17), and in that the spacing (E) of the first and second horns (16, 17), measured between respective points of the first and second horns (16, 17) which strike or are struck by the pin (8) during said pulses, is chosen greater than 1, 2 times, preferably greater than 1.3 times, preferably greater than 1 , 4 times, preferably greater than 1, 5 times, preferably greater than 1, 6 times, preferably greater than 1, 7 times, preferably greater than 1, 8 times, preferably greater than 1, 9 times, of preferably even greater than 2 times, the diameter (D) of the ankle (8).

19. Method according to any one of claims 12 to 18, characterized in that the striker (12) and the oscillator (4) are arranged so that each of said pulses is communicated to the oscillator (4) while it is substantially in its angular position of equilibrium.

20. Method according to any one of claims 12 to 18, characterized in that the striker (12) and the oscillator (4) are arranged so that each of said pulses is communicated to the oscillator (4) while it lies after its angular position of equilibrium.

21. A method according to any one of claims 12 to 20, characterized in that the constant force device (10) comprises a bistable elastic member.

22. Method according to any one of claims 12 to 21, characterized in that at least a portion (16-17) of the striker (12) and at least a portion (8) of the oscillator (4) arranged for cooperating with each other to communicate said pulses are each made of one of the following materials: steel, aluminum oxide, silicon, metal glass.