CH707881A2 - Exhaust system for a sprung balance resonator. - Google Patents

Abstract

The invention relates to a timepiece comprising a resonator (23) cooperating with an exhaust system (22). According to the invention, the exhaust system (22) comprises a movable escape wheel (3) arranged coaxially with the balance (1) and driven by the timepiece's work train, a first fixed wheel having a first gear (6) and a second fixed wheel having a second toothing (8), said first and second fixed wheels being arranged coaxially with the movable escape wheel (3) and a device (9) for fixing the outer end (10). ) of the hairspring (24) having a piece (11) articulated with respect to the movable escapement wheel (3) and arranged to ensure a radial displacement of said outer end (10) between said first and second sets of teeth (6, 8). ) to maintain the resonator (23) and distribute its movement to the wheel of the timepiece.

Description

Field of the invention

[0001] The invention relates to an escapement system for a sprung balance resonator and, more particularly, for such a high amplitude resonator.

Background of the invention

[0002] The purpose of an escapement system of a timepiece is to maintain and count the oscillations of the balance of a sprung balance resonator. To do this, it receives the energy dispensed by a barrel and at the end of the chain by a seconds wheel in order to periodically let out a part of this motive energy to restore to the resonator the energy lost in passive resistances (for example friction ), this resonator comprising a flywheel called balance on the axis of which is fixed a spiral spring called hairspring.

[0003] The mechanical energy Em of such a sprung balance resonator is given by the following relation:

in which: J is the inertia of the balance; ƒ is the frequency of the balance wheel; At the amplitude of the oscillation of the balance.

[0004] The watchmaking technique tends to increase the energy of the sprung balance resonator in order to improve its precision and its resistance to shocks, thanks to the increase in the inertia J of the balance and / or to the increase in the oscillation frequency of the balance. However, increasing these parameters poses great difficulties.

[0005] Indeed, increasing the inertia J of the balance tends to increase its weight, which induces unwanted dry friction and / or degrades its aerodynamics. On the other hand, the increase in the oscillation frequency ƒ requires a considerable increase in the virtual power which risks reducing the power reserve of the timepiece. We also understand that the increase in the oscillation frequency ƒ requires that the escapement functions are shorter and shorter, which represents a real kinematic and tribological challenge.

Summary of the invention

The object of the present invention is to overcome all or part of the drawbacks mentioned above by providing an alternative exhaust system for a sprung balance resonator which allows the increase in the mechanical energy Em of said resonator while avoiding pitfalls cited above.

[0007] To this end, according to a first variant, the invention relates to a timepiece comprising a resonator formed by a balance associated with a hairspring and cooperating with an escapement system characterized in that the system of The escapement comprises a movable escapement wheel arranged coaxially with the balance and driven by the gear train of the timepiece, a first fixed wheel having a first toothing and a second fixed wheel having a second toothing, the first fixed wheel being arranged at the 'inside the second fixed wheel in the same plane leaving a space forming a closed channel, said first and second fixed wheels being arranged coaxially with the movable escape wheel and a device for fixing the outer end of the hairspring comprising a part articulated with respect to the movable escape wheel and arranged to ensure, according to the winding state of the hairspring, a radial displacement of said outer end between lesdi your first and second teeth to maintain the resonator and distribute its movement to the cogwheel of the timepiece

[0008] According to a second variant, the invention relates to a timepiece comprising a resonator formed by a balance associated with a hairspring and cooperating with an exhaust system characterized in that the exhaust system comprises a wheel movable escapement arranged coaxially with the balance and driven by the gear train of the timepiece, a first fixed wheel having a first toothing and a second fixed wheel which, mounted above the first wheel, has a second toothing, the first toothing comprising an internal diameter smaller than that of the second toothing, said first and second fixed wheels being arranged coaxially with the movable escape wheel and a device for fixing the outer end of the hairspring comprising a part articulated with respect to the movable escape wheel and arranged to ensure, according to the winding state of the balance spring, a radial displacement of said outer end between said first and second teeth to maintain the resonator and distribute its movement to the cogwheel of the timepiece.

[0009] In these two variants, the part articulated with respect to the movable escapement wheel preferably comprises at least one pin to cooperate with the first and second teeth. However, more particularly in the second variant, the articulated part of the fixing device comprises a first arm at the end of which is fixed a first pin arranged to cooperate with the first teeth of the first fixed wheel, and a second arm at the end. end of which is fixed a second pin arranged to cooperate with the second set of teeth of the second fixed wheel, each arm being able to be offset in height.

We therefore see that instead of increasing the inertia J of the balance and / or the oscillation frequency ƒ, the exhaust system offers, advantageously according to the invention, to increase the amplitude A of the oscillation of the balance with the aim of increasing the mechanical energy of the resonator. Advantageously according to the invention, from relation (1), it is also seen that increasing the amplitude A of the oscillation of the balance will have a greater influence because the amplitude A occurs squared.

It will be noted here that, for low quality factor resonators, among which there is the sprung balance resonator where the Q factor is less than 1000, the operating disturbance induced by the exhaust system is the greater the greater the ratio between the sustain angle and the amplitude of oscillation. It is therefore understood, advantageously according to the invention, that increasing the amplitude A of the balance wheel considerably reduces said disturbances.

In known escapement systems of the anchor or detent type, this increase in amplitude is structurally not possible, the amplitude being generally limited to 320 degrees. In addition, the escapement system intervenes on the plate pin secured to the balance, whenever the balance passes through its equilibrium position or neutral point.

Advantageously according to the invention, if one wishes an amplitude exceeding the known limit of 320 degrees to reach at least one complete revolution of the balance and which can extend over several complete revolutions (this increase being not intrinsically limited), the present invention makes it possible to directly maintain the hairspring and not the balance as in traditional escapements. By directly maintaining the hairspring, the escapement system can be triggered by the movement of the hairspring, for example by the radial displacement of its outer end.

[0014] In accordance with other common advantageous features of the invention: the outer end of the hairspring is integral with a free end of said part articulated with respect to the movable escapement wheel or is integral with said at least one peg; the movable escapement wheel is mounted movable relative to a fixed part of the timepiece by means of a ball bearing; the fixed part of the timepiece is the plate; the balance and the inner end of the hairspring are fixed on a pivoting shaft between a bridge and the geometric center of the first fixed wheel; the mobile escape wheel consists of a cage enclosing the resonator, the balance and the inner end of the hairspring being fixed on a pivoting shaft between the walls of the cage, the latter pivoting between a bridge and the geometric center of the first fixed wheel; the first and second fixed wheels are made in one piece; the first and second teeth are formed by pins; said at least one anchor is magnetized and the teeth are made of paramagnetic material having a magnetic permeability greater than 1.5 or said at least one anchor is made of paramagnetic material having a magnetic permeability greater than 1.5 and the teeth are magnetized in order to allow magnetic bonding between said teeth and said at least one pin.

Brief description of the drawings

Other features and advantages will emerge clearly from the description which is given below, by way of indication and in no way limiting, with reference to the accompanying drawings, in which: FIG. 1 is a perspective view of a first embodiment of an exhaust system according to the invention; figs. 2 to 6 are plan views of the embodiment of FIG. 1 explaining the operation of an escapement system on two consecutive alternations of the sprung balance resonator according to the invention; fig. 7 is a graph accompanying the explanations relating to FIGS. 2 to 6; fig. 8 is a graph comparing the torques exerted, on the one hand, on the sprung balance resonator according to the invention and, on the other hand, on a sprung balance resonator cooperating with an escapement system of the Swiss lever type; fig. 9 is a sectional view of an exhaust system according to FIG. 1; fig. 10 is a sectional view of an exhaust system according to a second embodiment; fig. 11 is a plan view of an exhaust system according to a third embodiment; fig. 12 is a section along XII-XII of FIG. 11; fig. 13 is a section along XIII-XIII of FIG. 11; fig. 14 is a plan view of an exhaust system according to a fourth embodiment.

Detailed description of the preferred embodiments

A first embodiment of the present invention is illustrated in FIG. 1 which is a perspective view of an oscillator according to the invention, that is to say an escapement system 18 coupled to a sprung balance resonator 15. The resonator 15 according to the invention comprises a balance 1 associated with a balance spring 2.

[0017] For the clarity of the drawing and not to hide the elements located under it, the hairspring 2 is only represented by a limited number of turns. However, the hairspring 2 can, of course, have a larger number of turns without departing from the scope of the invention. The inner end 50 of the hairspring 2 is fixed to a shaft 43 such as, for example, by means of a ferrule (better visible in Fig. 9) formed. In the example illustrated in fig. 1, it can be seen that the balance 1 is also attached to the shaft 43.

[0018] According to the invention, the exhaust system 18 comprises a movable escapement wheel 3 disposed coaxially with respect to the resonator 15. In the example illustrated in FIG. 1, the movable escapement wheel 3 is driven by a seconds wheel 4 belonging to the cogwheel of the timepiece which is engaged with a barrel providing the driving force of the timepiece.

The exhaust system 18 further comprises a first fixed wheel 5 having an external toothing 6 and a second fixed wheel 7 having an internal toothing 8. In the example illustrated in FIG. 1, the two fixed wheels 5, 7 of the exhaust system 18 are arranged coaxially with the movable escape wheel 3 and fixed to a fixed point of the timepiece, such as its plate, for example, by means of screws 16 and 17. In addition, it can be seen that the first and second fixed wheels 5 and 7 are arranged in the same plane, the first wheel 5 being placed inside the second wheel 7 leaving a space, forming a closed channel. 56 substantially crenellated and symmetrical, in which a peg 14 can move.

[0020] Advantageously according to the invention, the mobile escapement wheel 3 is provided with a device 9 for fixing to the outer end 10 of the hairspring 2 in order to arm the latter. In addition, the fixing device 9 is arranged to ensure, depending on the winding state of the hairspring 2, a radial displacement of the outer end 10, the latter being caused to cooperate alternately with the teeth 6 of one. then the teeth 8 of the other of the first 5 and second 7 fixed wheels. It is understood that this radial displacement allows the exhaust system 18 to maintain the resonator 15 and the escapement of the seconds wheel 4.

A section of principle exerted on FIG. 1 is shown in fig. 9. The movable escapement wheel 3 is associated with an internal element 40 formed in the example of FIG. 9. The movable escapement wheel 3 - internal element 40 assembly is made movable in rotation with respect to a fixed point 42 of the timepiece, such as its plate, for example, preferably using a ball bearing 41 .

As best seen in FIG. 9, it can be seen that the balance 1 and the inner end 50 of the hairspring 2 are fixed on the shaft 43 pivoting between a bridge 44 and the geometric center of the first fixed wheel 5, whether real or virtual, as explained below. below.

Preferably according to the first embodiment of the invention, the fixing device 9 comprises a bar 11 articulated to ensure the radial displacement of the outer end 10 of the hairspring 2. The bar 11 is mounted, on the one hand , on a pivoting eyebolt 12 carried by the movable escape wheel 3 and, on the other hand, on the outer end 10 of the balance spring 2. In the example illustrated in FIG. 1, it can be seen that the outer end 10 of the hairspring 2 is integral with the pin 14 which can move in the closed channel 56 which is substantially crenellated and symmetrical and is intended to be fitted to the free end 13 of the bar 11. Preferably, the pin 14 is formed from the same material as the hairspring 2 or based on rubies.

When moving the pin 14 in the channel 56, to facilitate its release from one 6 then the other 8 of the teeth 6, 8 fitted to the fixed wheels 5 and 7, the pin 14 can be given the shape of a cylindrical pin with circular or elliptical section.

[0025] The operation of the exhaust system 18 according to the invention will now be explained with reference to FIGS. 2 to 6 and to the graph of fig. 7. These figures describe the movement of the ankle 14 during two consecutive alternations of the hairspring 2 by ensuring two consecutive escapements of the seconds wheel 4. In FIG. 7, curve A shows the angle in degrees traveled by resonator 15 as a function of time in seconds and, curve B, the angle in degrees traveled by movable escapement wheel 3 as a function of time in seconds.

[0026] a) In fig. 2, the hairspring 2 is in maximum contraction (point 52 in fig. 7) from which it enters a first expansion phase (region 53 in fig. 7) which ends when it reaches its position d. 'balance, or neutral point 54, phase during which the pin 14 is kept locked against an external tooth 6 of the first fixed wheel 5.

[0027] b) In fig. 3, from the equilibrium position (point 54 in fig. 7) the hairspring 2 enters a second expansion phase (region 55 in fig. 7) at the start of which the pin 14 is pushed radially, by the elastic deformation of the hairspring itself, out of the outer tooth 6 of the first fixed wheel 5 to be brought into the channel 56 between two inner teeth 8 of the second fixed wheel 7. It is therefore understood that the pin 14 is made free by its radial displacement relative to the wheels 5, 7.

[0028] c) In fig. 4, the peg 14 made free and, incidentally, the movable escapement wheel 3, are driven by the seconds wheel 4 under stress by the barrel of the timepiece. Consequently, the movable escape wheel 3 moves by a first impulse angle α which causes the pin 14 to abut and lock against an internal tooth 8 of the second fixed wheel 7. This movement drives the balance spring 2 to go through its second expansion phase 55 then a first contraction phase (region 58 in FIG. 7) during which the ankle 14 remains blocked against the same internal tooth 8. The second expansion phase 55 and the first phase contraction 58 define a first additional arc of the balance 1.

D) In fig. 5, the first contraction phase 58 ends when the hairspring reaches its equilibrium position (point 59 in fig. 7) from which the hairspring 2 enters a second contraction phase (region 60 in fig. 7) ) at the start of which the pin 14 is pushed radially out of the inner tooth 8 of the second fixed wheel 7 to be brought into the channel 56 between two outer teeth 6 of the first fixed wheel 5. It is therefore understood that the pin 14 is again made free by its radial displacement relative to the wheels 5, 7.

[0030] e) In FIG. 6, the peg 14 made free by its radial displacement and, incidentally, the movable escape wheel 3, are driven by the seconds wheel 4. Therefore, the movable escape wheel 3 moving by a second angle of pulse p which causes the ankle 14 to come up against and block against a new external tooth 6 of the first fixed wheel 5. This movement causes the balance spring 2 to go through its second contraction phase 60 then a new and repetitive first expansion phase (region 63 in fig. 7 similar to region 53) during which the pin 14 remains blocked against the new outer tooth 6. The second contraction phase 60 and new first expansion phase 63 define a second additional arc of the balance 1 .

[0031] In the first embodiment of FIGS. 1 to 6, fig. 7 shows that the essential object of the present invention is achieved, namely the increase in the amplitude A of the oscillation of the balance. Indeed, between position 52 and the point of inflection between regions 55 and 58, the amplitude A of balance 1 is of the order of 550 degrees, which greatly exceeds the 320 degrees reached by an exhaust system. of the Swiss anchor type. It is also understood that this increase in amplitude A is achieved by maintaining the resonator 15, that is to say by supplying energy, directly by the hairspring 2 by pulling its outer end 10 and not by the balance. 1 itself as in traditional Swiss lever escapements. Advantageously according to the invention, it is therefore no longer necessary to mount a plate on the balance shaft.

[0032] FIG. 8 is a graph comparing the torques transmitted in millinewtonmillimeters (mNmm), on the one hand, to the resonator 15 equipping the present invention (plot E) and, on the other hand, to an energetically equivalent balance-spring resonator equipping a system of ' Swiss lever type escapement (line F). It can be seen that the torque imparted to the resonator 15 according to the invention during the angle during which it is applied is clearly greater (maximum of the order of 0.25 mNmm) than that imparted to the balance-spring resonator of a conventional exhaust system (maximum of the order of 0.06 mNmm), which explains faster acceleration of the balance 1 according to the invention and, incidentally, makes it possible to achieve a greater amplitude of its oscillation. It is also understood, advantageously according to the invention, that the instantaneous speed during passage through the point of rest is greater. However, for impact maintenance systems, the lower instantaneous speed is an inherently crippling limitation.

[0033] FIG. 7 also shows that the angles a and (3 illustrated respectively in FIGS. 4 and 6 are each substantially equal to 30 degrees and are traversed (a + (5) in 0.25 seconds for a frequency substantially equal to 4 Hz. It follows that the movable escape wheel 3 makes one revolution in approximately 1.5 seconds It is therefore understood that this same rotational movement affects the resonator 15 which rotates in the manner of a vortex with a similar effect, that is to say - say that this rotation making it possible to average and correct the effects of gravity on the resonator 15.

Consequently, advantageously according to the invention, besides the increase in the mechanical energy Em due to the increase in the amplitude A of the oscillation of the balance 1, the exhaust system 18 makes it possible to correct the gravity effects. It is also understood that the exhaust system 18 offers the guarantee of self-starting of a high-frequency movement even with great rigidity, increasing the stability and the quality factor in the absence of shock. maintenance, elimination of the risk of rebate and overturning which are intrinsic to the architecture, improvement of the efficiency of the exhaust functions because the losses are due only to friction in the pivots and a mobile and the reduction in the number of components to be oiled by removing the anchor.

Of course, the present invention is not limited to the first embodiment but is susceptible of various variants and modifications while retaining the effects and advantages mentioned above. In particular, a second embodiment of the exhaust system 21 according to the invention is illustrated in FIG. 10. In this second embodiment, the movable escape wheel 3 of the first embodiment is replaced by a toothing 19 formed on the outside of a cage 45. The cage 45 encloses a resonator 20 which is of the same type as the resonator 15 of the first embodiment. Thus, the balance 1 and the inner end 50 of the hairspring 2 are fixed to a shaft 46 pivoting between the walls 47 and 48 of the cage 45. As visible in FIG. 10, the cage 45 of the exhaust system 21 is pivotally mounted between a bridge 49 and the center of the first fixed wheel 5.

[0036] A third embodiment of the exhaust system 22 according to the invention is illustrated in FIGS. 11 to 13. The exhaust system 22 differs from the previous two embodiments in that the first and second fixed wheels 5 and 7 are made in one piece.

In order to better explain this third embodiment, FIGS. 12 and 13 were made according to sections XII and XIII respectively of FIG. 11. The resonator 23 of the third embodiment is of the same type as the resonator 15, 20 of the first two embodiments. We therefore find the balance 1 equipped with balancing screws 70 and connected to the shaft 43 by means of four arms 71. The shaft 43 is pivotally mounted between the bridge 44 and a bearing 72 integral with a block 51 which incorporates in one piece, the outer teeth 6 and inner teeth 8, formed, in the first two embodiments, by the fixed wheels 5 and 7.

The balance 1 is associated with the hairspring 24 having more turns than the hairspring 2 of the first embodiment and the end of the inner coil 50 of which is fixed to the shaft 43, for example by means of a ferrule. The end of the outer coil 10 is attached to the pin 14 fixed to the free end 13 of the bar 11, the latter being articulated on the pin 12 carried by the movable escape wheel 3 as for the first embodiment. . The movable escape wheel 3 is provided with toothing 73 in mesh with the seconds wheel 4 also as for the first embodiment and is associated with the internal element 40 of a ball bearing 41 whose element external 42 is integral with the block 51 fixed to a fixed point of the timepiece, such as for example its plate.

Finally, a fourth embodiment according to the invention is illustrated in FIG. 14. The resonator 25 of the fourth embodiment is of the same type as the resonator 15, 20, 23 of the first three embodiments. Contrary to what has been shown in the three embodiments above in which the first and second fixed wheels 5, 7 were located in the same plane, in the fourth embodiment, the exhaust system 25 has first and second fixed wheels 70, 71 which are placed one on top of the other. The first and second fixed wheels 70, 71 respectively comprise first and second internal teeth 72, 73 which overlap.

It is also observed in FIG. 14 that the first teeth 72 has an internal diameter smaller than that of the second teeth 73. In the fourth embodiment, the fixing device 74 differs from that of the first three embodiments. Thus, the fixing device 74 comprises a rocker 75 articulated on a pin 12 carried by the movable escape wheel 3. The rocker 75 carries a first arm 76 at the end of which are fixed the outer end 10 of the balance spring 2 and a first pin 77 arranged to cooperate with the first teeth 72 of the first fixed wheel 70. The rocker 75 also carries a second arm 78 at the end of which is fixed a second pin 79 arranged to cooperate with the second teeth 73 of the second fixed wheel 71. Preferably, each peg 77, 79 is formed from the same material as the balance spring 2 or based on rubies.

[0041] FIG. 14 shows a hairspring 2 of the type of the first embodiment in maximum expansion. The first peg 77 is kept locked against a first tooth 72 of the first fixed wheel 70. When the hairspring 2 contracts, the peg 77 moves radially inward causing the rocker 75 to pivot counterclockwise and the first peg 77 to free itself from a first tooth 72.

The second pin 79 of the rocker 75 then enters the space separating two second teeth 73 which frees the movable escape wheel 3 which then progresses by a first pulse angle by driving the second wheel 4 until the second pin 79 abuts against a second tooth 73 of the second fixed wheel 71.

A second pulse angle is traversed when, the balance spring 2 passing in expansion, the second pin 79 is released from the second tooth 73, the lever 75 then rotating in the clockwise direction. The first pin 77 then falls into the space between two first teeth 72 and the movable escape wheel 3 then by a second impulse angle by driving the second wheel 4 until the first pin 77 comes. abut against a first tooth 72 of the first fixed wheel 70. It will be noted that in this fourth embodiment, the fixed wheels 70 and 71 being arranged one on top of the other, the second pin 79 must have a shorter length by compared to the length of the first peg 77.

[0044] Of course, the present invention is not limited to the example illustrated but is susceptible to various variations and modifications which will appear to those skilled in the art. In particular, the four embodiments presented above can be combined in order to adapt to the installation constraints while retaining the effects and advantages mentioned above common to the four embodiments. By way of non-limiting example, the first 70 and second 71 fixed wheels of the fourth embodiment could be made in one piece as proposed in the third embodiment.

It is also possible that the part articulated relative to the movable escape wheel 3, 19, 45, that is to say by the lever 75 or the bar 11, is replaced by a part of different shape such as a part substantially in the form of a half cylinder.

In an embodiment comprising several pegs 14, 77, 79 such as the fourth embodiment, it can be envisaged that the arms 76, 78 of the articulated part 75 relative to the movable escape wheel 3, 19, 45 are offset in height.

In addition, the first and second teeth 6, 8, 72, 73 should be understood as stops or contact surfaces for stopping and locking said at least one pin 14, 77, 79. To this As a result, the first and second teeth 6, 8, 72, 73 may be formed by pins, that is to say rods extending substantially parallel with respect to said at least one pin 14, 77, 79 in order to '' come into contact with according to the operation explained above. It is therefore understood that the first and / or second teeth 6, 8, 72, 73 may in a way be skeletonized, that is to say not be entirely solid.

Finally, in order to improve the locking of the above embodiments, a magnetic bonding between said teeth and said at least one peg can also be provided. Consequently, by way of example, said at least one pin 14, 77, 79 can be magnetized and the teeth 6, 8, 72, 73 can be made of a paramagnetic material having a magnetic permeability greater than 1.5, or vice versa, said at least one pin 14, 77, 79 can be magnetized and the teeth 6, 8, 72, 73 can be made of a paramagnetic material having a magnetic permeability greater than 1.5.

Claims (18)

1. Timepiece comprising a resonator (15, 20, 23) formed by a rocker (1) associated with a hairspring (2, 24) and cooperating with an exhaust system (18, 21, 22) characterized in that that the exhaust system (18, 21, 22) comprises a movable escapement wheel (3, 19, 45) arranged coaxially with the balance (1) and driven by the timepiece's wheel, a first fixed wheel (5) having a first toothing (6) and a second fixed wheel (7) having a second toothing (8), the first fixed wheel (5) being disposed within the second fixed wheel (7) in the same plane leaving a closed channel space (56), said first and second fixed wheels (5, 7) being disposed coaxially with the movable escape wheel (3, 19, 45) and a device (9) for securing the outer end (10) of the hairspring (2, 24) having a piece (11) articulated with respect to the movable escape wheel (3, 19, 4 5) and arranged to ensure, according to the state of winding of the hairspring (2, 24), a radial displacement of said outer end (10) between said first and second toothing (6, 8) to maintain the resonator (15, 20, 23) and distribute its movement to the wheel of the timepiece. 2. Timepiece according to the preceding claim, characterized in that the piece (11) articulated relative to the movable escape wheel (3, 19, 45) comprises at least one pin (14) to cooperate with the first and second teeth (6, 8). 3. Timepiece according to the preceding claim, characterized in that the outer end (10) of the hairspring (2) is integral with a free end (13) of said piece (11) articulated relative to the wheel d mobile exhaust (3, 19, 45). 4. Timepiece according to claim 2, characterized in that the outer end (10) of the spiral (2) is integral with said at least one pin (14). 5. Timepiece comprising a resonator (26) formed by a rocker (1) associated with a hairspring (2) and cooperating with an exhaust system (25) characterized in that the exhaust system (25) comprises a movable escapement wheel (3) arranged coaxially with the balance (1) and driven by the timepiece's work train, a first fixed wheel (70) having a first toothing (72) and a second fixed wheel (71) which, mounted above the first wheel (70), has a second toothing (73), the first toothing (72) having an internal diameter smaller than that of the second toothing (73), said first and second fixed wheels (70, 71) being arranged coaxially with the movable escapement wheel (3) and a device (74) for fixing the outer end (10) of the spiral (2) comprising a piece (75) articulated with respect to the mobile escapement wheel (3) and arranged to ensure, according to the condition of a rmage the spiral (2), a radial displacement of said outer end (10) between said first and second set of teeth (72, 73) to maintain the resonator (26) and distribute its movement to the wheel of the timepiece. 6. Timepiece according to the preceding claim, characterized in that the piece (75) articulated relative to the movable escape wheel (3, 19, 45) comprises at least one pin (77, 79) to cooperate with the first and second teeth (70, 71). 7. Timepiece according to the preceding claim, characterized in that the articulated part (75) of the fixing device (74) comprises a first arm (76) at the end of which is fixed a first pin (77) arranged for cooperating with the first toothing (72), and a second arm (78) at the end of which is fixed a second pin (79) arranged to cooperate with the second toothing (73). 8. Timepiece according to the preceding claim, characterized in that the arms (76, 78) of the rocker (75) are offset in height. 9. Timepiece according to one of claims 6 to 8, characterized in that the outer end (10) of the spiral (2) is secured to a free end of the part (75) articulated relative to the mobile escapement wheel (3, 19, 45). 10. Timepiece according to one of claims 6 to 8, characterized in that the outer end (10) of the spiral (2) is integral with said at least one pin (77, 79). Timepiece according to one of the preceding claims, characterized in that the movable escapement wheel (3) is mounted movably relative to a fixed part of the timepiece by means of a bearing. with balls (41). 12. Timepiece according to the preceding claim, characterized in that the fixed part of the timepiece is the platinum. 13. Timepiece according to one of the preceding claims, characterized in that the rocker (1) and the inner end (50) of the spiral (2, 24) are fixed on a shaft (43) pivoting between a bridge (44) and the geometric center of the first fixed wheel (5). 14. Timepiece according to one of claims 1 to 10, characterized in that the movable escapement wheel (19, 45) consists of a cage (45) enclosing the resonator (20), the balance ( 1) and the inner end (50) of the hairspring (2) being fixed on a shaft (46) pivoting between the walls (47, 48) of the cage (45), the latter pivoting between a bridge (49) and the geometric center of the first fixed wheel (5). 15. Timepiece according to one of the preceding claims, characterized in that the first (5, 70) and second (7, 71) fixed wheels are made in one piece. 16. Timepiece according to one of claims 1 to 14, characterized in that the first and second teeth (6, 8, 72, 73) are formed by pins. 17. Timepiece according to one of claims 2 to 4 and 6 to 16, characterized in that said at least one pin (14, 77, 79) is magnetized and the teeth (6, 8, 72, 73) are made of paramagnetic material having a magnetic permeability greater than 1.5 to allow magnetic bonding between said teeth and said at least one peg. 18. Timepiece according to one of claims 2 to 4 and 6 to 16, characterized in that said at least one pin (14, 77, 79) is made of paramagnetic material having a magnetic permeability greater than 1.5 and the teeth (6, 8, 72, 73) are magnetized in order to allow magnetic bonding between said toothing and said at least one peg.