EP3547041B1 - Time-piece comprising a mechanical oscillator - Google Patents

Description

This invention relates to a hairspring type timepiece with a hairspring and a balance wheel. The invention is particularly suitable for wristwatches but can also be applied to other time measuring mechanisms such as table clocks, wall clocks and other instruments fulfilling the function of timepieces.

The Abraham-Louis Breguet timepiece number 282, described and illustrated in “Das Tourbillon” (1993, Reinhard Meis) on pages 90 and 91, covers the preamble of claim 1 attached.

CH 711 571 / EP 3 147 725 describe a rotating detent escapement, to maintain the oscillation of a monolithic oscillator (inertia elasticity). The trigger is also monolithic. The impulse is given by a direct torque. It is the balance shaft which receives the engine torque directly. The relaxation allows this engine torque to be released. It is an oscillator on a flexible pivot whose small operating amplitude makes it possible to eliminate the risks of galloping (jumping of the trigger teeth, at the level of the escape wheel) and therefore to resolve the main disadvantage detent escapements in a watch.

CH 709 279 describes a regulating device which imposes a periodic movement at least of the rest point of the resonator with a regulation frequency between n*0.9w and n*1.1w0, with n integer > or = 2 and w0 natural frequency of the main resonator. It would, however, be desirable to impose on the pin a periodic rotational movement around the axis of the balance, with a periodic movement whose frequency is much lower than the natural frequency of the spiral balance resonator.

EP 1097 408 B1 describes a constant-torque hairspring-balance type time indicator, with a hairspring and a balance wheel. An oscillation of the balance wheel is maintained through an escapement mobile by displacement of a point of attachment of the spiral spring at the moment of passage to the point of impulse of the oscillator, resulting in a circular movement of the point of attachment of the spiral spring around the axis of the oscillator and causing rotation of the balance-spring-escapement assembly. In this known device, one end of the spiral spring, the internal end, is fixed by a fixing pin to the exhaust mobile. The other end of the spiral spring, the outer end, is attached to the balance wheel. The pin for fixing the spiral spring being integral with the escapement mobile, it transmits to the spiral spring the angular movement with which it has just been animated, storing potential energy in the spiral spring which will initiate the oscillation of the balance.

The aim of this invention is to provide a mechanical timepiece of the balance spring type, comprising a balance spring, a balance wheel and an escapement mechanism connected by a point of attachment to the balance spring and arranged to maintain oscillation of the balance wheel. , which has minimal disturbance on its reference oscillator and the frequency of the oscillator is more stable and the measurement of time more precise.

The invention is as defined in claim 1.

The invention also relates to a timepiece, such as a wristwatch, a table clock or a wall clock, comprising a timepiece as described.

The invention makes it possible to simultaneously reduce the influence of several sources of disturbances coming from counting the number of oscillations of the balance (by reducing the number of interactions per cycle), maintaining its amplitude as well as the influence of the orientation of the oscillator in the gravitational field. The invention combines the advantages of a detent escapement with the displacement of the point of attachment of the spring of the reference oscillator and the use of a sun gear acting as a tourbillon.

The invention benefits from the principle of the expansion escapement. The detent escapement is known to have a reduced influence on the regular operation of the timepiece compared to other traditional escapements. The invention introduces a variant of the expansion escapement which makes it possible to further reduce its influence by eliminating or at least reducing the need for the impulse shock used to maintain the amplitude of oscillation.

All or part of the maintenance of the oscillation amplitude of the oscillator is obtained by moving the fixing point of its return member (the spring pin in the case of a traditional balance wheel).

The present invention is a particular application of the family of tourbillon timepieces used in other forms since the 18th century. The oscillator thus that the escapement executes a complete rotation in a few tens of seconds in the same plane as the oscillator.

With the present invention, the oscillator is minimally disturbed. In fact, the transfer to the escape mechanism of part of the energy of the oscillation system necessary to clear the teeth of the escape wheel only influences the operation of the oscillator once per cycle, which allows for a reduced disturbance to the operation of the oscillator. The influence of counting the number of oscillations on a traditional mechanism with an anchor escapement induces two disturbances per cycle of the oscillator.

Furthermore, the movement of the eyebolt in place of or in addition to the impulse given by the traditional escapement mechanism ensures that the amplitude of oscillation is maintained without there being, or at least in reducing the disruptive shock of oscillator operation.

A weak point of the detent escapement is the risk of the trigger being released for too long, which can then cause the release of several teeth of the escape wheel (gallop). The mechanism as described in the present invention avoids this problem because the escape wheel is slowed down by the inertia of the chassis and the trigger thus has time to return to its position in time and avoid galloping.

Another advantage of the present invention is that the oscillator and the escapement mechanism make a complete revolution in a few tens of seconds on themselves in the plane of the oscillator thanks to the planetary device, and thus average the negative influences of the unbalance of the balance when the plane of oscillation of the balance is not perpendicular to the gravitational field.

The energy transmitted to the oscillator by the movement of the attachment point of the hairspring is constant and depends on the distance of the movement of the pin which is constant. The energy transmitted to the oscillator to maintain its amplitude by this movement no longer depends on the force of the barrel as soon as this force is sufficient to ensure the movement of the pin.

Furthermore, with a specific choice of the gear train ratio of the plantar, it is possible to ensure a constant amplitude of the oscillation and thus, to optimize its properties by the choice of the amplitude of oscillation (by example 220°).

• La figure 1 représente une vue en perspective partielle d'un garde-temps selon un mode de réalisation proche de la présente invention avec le ressort-spiral partiellement découpé ;
• La figure 2 représente une vue arrière de la figure 1 ;
• La figure 3 représente une vue en perspective d'un autre garde-temps selon un mode de réalisation proche de l'invention ; et
• Les figures 4 et 5 représentent respectivement une vue en perspective et une vue de dessus d'un garde-temps selon l'invention dont les dents de la roue d'échappement comportent un plan incliné et un plan de dégagement.

The characteristics of the invention will appear more clearly on reading the description of several embodiments given solely by way of example, in no way limiting, with reference to the following figures in which:

• There figure 1 represents a partial perspective view of a timepiece according to an embodiment close to the present invention with the spiral spring partially cut out;
• There figure 2 represents a rear view of the figure 1 ;
• There Figure 3 represents a perspective view of another timepiece according to an embodiment close to the invention; And
• THE figures 4 and 5 represent respectively a perspective view and a top view of a timepiece according to the invention whose teeth of the escape wheel comprise an inclined plane and a clearance plane.

There figure 1 illustrates, by way of example, a mechanical timepiece according to an embodiment close to the invention of the sprung balance type, comprising a spiral spring 10, a balance 20 and a trigger escapement mechanism 30 connected by a point of attachment to the spiral spring and arranged to maintain oscillation of the balance wheel.

As illustrated, the trigger escapement mechanism 30 is connected to the attachment point 12 of the spiral spring 10 by a frame 40 which pivots around the axis A of the balance. An external end 12 of the spiral spring 10 is attached to this frame 40 at a location located on one side of the balance axis A, the internal end of the spiral spring 10 being fixed towards the center of the balance 20. The mechanism d The detent escapement 30 is located on the other side of the balance axis A and acts on the pivoting frame 40 to rotate it around the axis A and thus rotate around the axis A at the attached end 12 of the spiral spring 10.

The balance wheel 20 is mounted on, and coaxial with, a fixed ring gear 22 comprising internal teeth 46, and the frame 40 carries said other side of the axis A balance, a satellite pinion 42 which engages with said toothed ring 22 and which is driven step by step by the detent escapement mechanism 30.

The frame 40 comprises several branches extending on either side of the axis of rotation of the balance 20 at an angle of approximately 120°. The chassis 40 forms a rotating plate whose axis of rotation coincides with the axis of rotation A of the balance 20.

The timepiece according to an embodiment close to the invention comprises an escape wheel 32 coaxial and integral with the satellite pinion 42.

The detent escapement mechanism 30 comprises an exhaust body 39 pivoting between a rest position engaging with the escape wheel 32 and a position for disengaging the escape wheel 32. This pivoted exhaust body 39 comprises a flexible trigger blade, a trigger rest plane 37 which engages with the escape wheel 32, and a stop of the flexible trigger blade 38 located in the trajectory of an impulse pin 24 integral in oscillation with the balance 20, which impulse pin 24 during the oscillation of the balance 20 moves the escapement lever 36/37/38/39 from its rest position to its release position.

The exhaust body 39 is pivotally mounted at one of the external ends of the chassis 40.

As illustrated, the outer end 12 of the spiral spring 10 is attached to one end of the frame 40 by a pin 14 which extends vertically between the plane of the frame 40 and the plane of the spiral spring 10.

The escape wheel 32 has a release plane 50 on its teeth 52 interacting with the resting plane of the trigger 37 of the escape mechanism 30, said release plane 50 preventing a rapid return of the trigger after its release.

There figure 1 illustrates the timepiece in its position where the impulse pin 24 while advancing (oscillation of the balance 20 in the opposite direction of clockwise in the drawing) leaves the escapement body 39 in its rest position with the rest plane 37 engaged against the escape wheel 32 in order to block this and the satellite pinion 42. Then the balance 20 continues its oscillation in this direction, then reverses its direction of oscillation. When the impulse pin 24, oscillating clockwise, strikes the end of the stop of the flexible blade 38, the exhaust body 39 moves and releases the tooth 37 from its engagement with the escape wheel 32 which is therefore free to rotate and the satellite pinion 42 rotates with the escape wheel 32 and moves the chassis 40. When the direction of oscillation is changed again, the impulse pin 24, when passing in front of the trigger, bends the flexible trigger blade 36 and passes the end of the stop of the flexible trigger blade 38 without clearing the escape wheel 32, arriving at the starting position illustrated, and so following.

The concept described is based on a traditional balance-spring oscillator. The entire mechanism rests on the chassis 40, the axis of rotation of which coincides with the axis of rotation of the balance wheel 20. The satellite pinion 42 meshes with the planetary crown 22. The detent escapement 30, the gear wheel exhaust 32, the satellite wheel 42, the support for the pin 14 of the spiral spring 10 are all adjacent to the satellite chassis. The satellite pinion 42 and the escape wheel 32 are integral.

The planetary ring 22 is fixed (does not oscillate or rotate). A rotational torque is exerted on the chassis pinion 45 ( figure 2 ). This torque tends to rotate the satellite pinion 42 and thus the chassis. The satellite pinion 42 is retained in its rotation by the blocking of the escape wheel 32 by the trigger mechanism 30. The rotation of the escape wheel 32 is only possible once per oscillation cycle of the balance 20 when it releases the relaxation mechanism 30. Thus, once per oscillation cycle of the balance 20, the satellite carrier plate will be able to rotate the amplitude of which depends on the ratio of the numbers of teeth of the different wheels. This rotation will cause a movement of the pin 14 to ensure or contribute to maintaining the amplitude of oscillation of the balance 29. The relaxation mechanism therefore does not necessarily act on the balance 20 to maintain its amplitude of oscillation by an action direct as in the case of a traditional expansion escapement. In a variant, the arm comprising the rest plane 37, pushed by the escape wheel 32, can be extended so that the trigger mechanism also acts on the impulse element. In this variant, the energy transmitted to the balance to maintain its amplitude is then distributed between the movement of the pin and the impulse of the extended arm of the trigger. In both variants, the chassis pinion 45 ( figure 2 ) also makes a rotation which ensures the counting of the number of cycles of oscillations carried out by the balance 20.

The angle of rotation of the planet carrier plate can be calculated to ensure an optimum amplitude of the angle of rotation of the balance wheel 20 in regular operation.

A set of wheels links a barrel (not illustrated) which ensures the torque on the satellite pinion 42 by the chassis pinion 45 and by the ratio of the teeth of the wheels, it is possible to obtain an adequate rotation speed for each of between them to display, for example, hours, minutes, and seconds or other measures of time.

There Figure 3 illustrates another embodiment of a mechanical timepiece according to an embodiment close to the invention of the sprung balance type, comprising a spiral spring 10, a balance 20 and a trigger escapement mechanism 30 connected by a point of attachment to the spiral spring and arranged to maintain oscillation of the balance wheel.

As illustrated in Figure 3 , the trigger escapement mechanism 30 is connected to the attachment point 12 of the spiral spring 10 by a transverse part 40 which pivots around the axis A of the balance. An external end 12 of the spiral spring 10 is attached to this transverse part 40 at a location located on one side of the balance axis A, the internal end of the spiral spring 10 being fixed towards the center of the balance 20. The mechanism trigger escapement 30 is located on the other side of the balance axis A and acts on the pivoting transverse part 40 to rotate it around the axis A and thus rotate around the axis A attached end 12 of spiral spring 10.

The balance wheel 20 is mounted on, and coaxial with, a fixed toothed wheel 22 having external teeth, and the transverse part 40 carries, on said other side of the balance axis A, a satellite pinion 42 which engages with said crown toothed 22 and which is driven step by step by the trigger escapement mechanism 30.

The transverse part 40 comprises two branches extending on either side of a disc 44 coaxial with the balance 20. This disc 44 forms with the transverse part 40 a frame or a turntable whose axis of rotation coincides. with the axis of rotation of the balance 20.

The timepiece according to the invention comprises an escapement wheel 32 coaxial and integral with the satellite wheel 42. In a variant close to the invention, the detent escapement mobile could be replaced by another escapement device .

In the embodiment according to the invention illustrated in figures 4 and 5 , the timepiece has two types of impulse. A first type of impulse occurs when the amplitude of oscillation of the balance wheel is low. This is a direct impulse from a tooth of the escape wheel 52 which acts on an additional pin 48. The inertia of the mobile escape wheel added to the inertia of the mobile chassis as well as the engine torque are chosen such that this type of pulse only occurs when the speed of passage of the balance is relatively low, i.e. when the amplitude of said balance is low. Once a threshold of oscillation amplitude of the balance has passed, the escape wheel is no longer able to catch up with the balance during its acceleration phase and no longer comes into contact with the additional pin 48. There thus has more shock disrupting the oscillation frequency of the balance wheel.

In a second phase, where the direct impulses no longer take place, only the impulses by displacement of the point of attachment of the eyebolt to the chassis take place. This type of impulse occurs regardless of the amplitude of the pendulum oscillations. Potentially, this type of impulse disrupts the oscillation frequency of the pendulum much less than the direct shock.

In addition, when the balance moves in the direction of release of the trigger, the balance rotates the trigger through its pin, the beak of the tooth of the escape wheel leaves the resting plane of the trigger , it arrives on the inclined plane 54 of the trigger and rotates it so as to allow the balance to pass. However, the latter having a much lower inertia than the balance, it tends to return to its initial position too quickly with the risk of interacting again with the pin of the balance. There is thus a risk of multiple contacts between the trigger and the balance pin, which is not desirable.

Thus, in order to prevent multiple contacts, the escape wheel is provided with a release plane 50, provided so that the trigger is maintained in its passing position until the balance is released. The release of the balance wheel is guaranteed by the interaction between a tooth of the escape wheel 52 and the additional pin 48 whose angle it forms with the balance pin has been established for this purpose.

Legend

10

spiral spring

12

attachment point/outer end of spiral spring

14

piton

20

pendulum

22

crown or fixed gear

24

impulse ankle

30

escape mechanism

32

escape wheel

36

flexible trigger blade

37

relaxation rest plan

38

flexible trigger blade stop

39

body relaxation

40

transverse part called frame

42

satellite gear

44

disk

45

chassis pinion

46

internal teeth

48

additional ankle

50

clearance plan

52

escape wheel tooth

54

inclined plane

Claims (10)

1. Mechanical timepiece of balance-spiral type, comprising a spiral spring (10), a balance (20) and an escapement mechanism (30) linked by an attachment point (12) to the spiral spring and arranged to sustain an oscillation of the balance, in which the escapement mechanism (30) is linked to the attachment point (12) of the spiral spring by a part hereinafter called frame (40) pivoted about the axis (A) of the balance, an outer end (12) of the spiral spring (10) is attached to this frame (40) at a point situated on one side of the balance axis (A), and

   the escapement mechanism (30) is situated on the other side of the axis (A) of the balance and acts on the pivoted frame (40) to make it turn and thus make the attached end (12) of the spiral spring turn,

   in which the balance (20) is mounted on, and coaxial with, a fixed toothed crown (22) and the frame (40) bears, on said other side of the balance axis (A) a satellite (42) which engages with said toothed crown (22) and which is driven stepwise by the escapement mechanism (30),

   the timepiece comprising an escapement wheel (32) coaxial and secured with the satellite (42), and an escapement lever (36, 37, 38, 39) with detent pivoting between an idle position engaging with the escapement wheel (32) and a position of disengagement from the escapement wheel (32), and

   in which the outer end (12) of the spiral spring is attached to the frame (40) by a balance spring stud (14) which extends vertically between the plane of the frame (40) and the plane of the spiral spring (10), the plane of the spiral spring (10) being disposed between the plane of the frame (40) and the balance (20),

   characterized in that the escapement wheel (32) has a plane of disengagement (50) on its teeth (52) interacting with a short arm (36) of the escapement mechanism (30), said plane of disengagement (50) preventing a very rapid return of the detent after the release thereof.
2. Timepiece according to Claim 1,
   in which the frame comprises several branches extending on either side of a disc (44) coaxial with the balance (20) and forming with the frame (40) a revolving plate whose axis of rotation coincides with the axis of oscillation of the balance (20).
3. Timepiece according to Claim 1 or 2,
   in which the escapement lever (36, 37, 38, 39) comprises said short arm (36) which is a short inner arm (36) provided with an engagement tooth (37) which comes to be engaged with the escapement wheel (32), and a long outer arm (38) situated in the trajectory of an impulse element (24) secured in oscillation with the balance (20), which impulse element (24), upon the oscillation of the balance (20), displaces the escapement lever (36, 37, 38, 39) from its idle position to its disengagement position.
4. Timepiece according to one of the preceding claims, in which the satellite (42) and the frame (40) are arranged to be driven in rotation by a frame pinion (45), said satellite (42) being retained in its rotation by the blocking of the escapement wheel (32) by the escapement mechanism (30), the rotation of the escapement wheel (32) being performed once per cycle of oscillation of the balance (20), when the balance (20) releases the detent mechanism (30), such that the revolving plate makes a rotation, the amplitude of which depends on the ratio of the number of teeth of the different wheels of the timepiece, the rotation of the revolving plate driving a displacement of the balance spring stud (14) to ensure or contribute to the amplitude of oscillation of the balance (20) being maintained.
5. Timepiece according to Claim 4,
   in which the frame pinion (45) is arranged to perform a rotation ensuring the counting of the number of oscillation cycles performed by the balance (20).
6. Timepiece according to Claim 1,
   in which the sum of the inertia of the escapement wheel (32) added to the inertia of the frame (40) is arranged such that a direct impulse of a tooth (52) of the escapement wheel (32) on an additional pin (48) occurs when the speed of passage of the balance (20) is low, that is when the amplitude of oscillation of the balance (20) is low.
7. Timepiece according to Claim 6,
   in which, when said direct impulses no longer take place, impulses by displacement of the point of attachment of the balance spring stud (14) to the frame (40) take place regardless of the amplitude of the oscillations of the balance (20).
8. Timepiece according to Claim 7,
   in which the escapement wheel (32) is provided with a plane of disengagement (50), provided in order for the detent to be maintained in its passing position, for the time that the balance (20) is disengaged, the disengagement of the balance (20) being guaranteed by the interaction between a tooth of the escapement wheel (52) and the additional pin (48).
9. Timepiece according to Claim 8,
   in which, when the balance (20) passes in the direction of disengagement of the detent, the balance (20) makes the detent mechanism (30) pivot by the intervention of its pin, the beak of the tooth of the escapement wheel leaving the idle plane of the detent to arrive on an inclined plane (54) of the detent and make the latter pivot so as to allow the balance to pass.
10. Timepiece, from among a wristwatch, a table clock or a wall clock, comprising a timepiece according to one of the preceding claims.

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