Classifications

• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B17/00—Mechanisms for stabilising frequency
  • G04B17/04—Oscillators acting by spring tension
  • G04B17/045—Oscillators acting by spring tension with oscillating blade springs
• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B15/00—Escapements
  • G04B15/10—Escapements with constant impulses for the regulating mechanism

Definitions

• the present invention relates to a method for transmitting pulses of mechanical energy from a motor source to an oscillating regulator of a timepiece via an elastic deformable mechanical element capable of accumulating energy. from said source between two pulses and to transmit it to this regulator at each pulse, as well as to an escape mechanism for the implementation of this process.
• the escapement mechanism of timepieces is intended on the one hand to deliver pulses of mechanical energy to maintain the oscillations of the regulator with a constant amplitude and, on the other hand, to communicate a controlled rotation to the gear train carrying the indicator bodies.
• the best known escapements have relatively poor yields which are around 40%, thus penalizing the power reserve, the number of winding turns of a stiffened barrel spring conditioned between the barrel shaft and the barrel drum being necessarily smaller.
• the flywheel can be uncoupled from the escape wheel, so that the impulse transmitted to the regulator is characteristic of a single winding of the above-mentioned spiral spring and is therefore of constant value, the winding angle of this balance spring being constant.
• Such a system constitutes a sort of filter placed between the gear train and the exhaust, but does not modify the behavior of the exhaust itself.
• Marti Another mechanism, known as the Marti system, comprises a detent member whose role is approximately similar to that of the anchor of an anchor escapement, that is to say of communicating periodic pulses to the regulator to maintain its oscillation.
• This expansion member is therefore driven by an alternating movement between two limit positions, synchronized by the oscillator and is kinematically integral with one end of a spiral spring, the other end of which is fixed to the frame of the workpiece. watchmaking.
• This hairspring is armed during the time separating two pulses, the latter being communicated to the regulator thus having the energy necessary to maintain its amplitude of oscillation stable.
• the object of the present invention is to remedy, at least to a certain extent, the two aforementioned drawbacks which affect the power reserve and the chronometric performance of timepieces and more precisely, of all the mechanical movements of wristwatches.
• the present invention firstly relates to a method for transmitting pulses of mechanical energy from a motor member to a regulator member of a timepiece as mentioned above, according to claim 1.
• This invention also relates to an escape mechanism for the implementation of this process as defined by claim 14.
• the energy accumulator works perfectly symmetrically, so that the oscillating regulator receives a constant energy pulse each time sandwich course.
• the gear train turns in spurts with a duration of 5 ms per half-period of 125 ms of l 'oscillator.
• the present invention allows the gear train to rotate for most of each half period. The gear train therefore has less jerky kinematics and, the angular accelerations being weaker, the inertias to be overcome are significantly reduced.
• the kinematics of the indicator hand is therefore also less jerky since, instead of moving for 5 ms and being stationary for 120 ms, the second hand moves during the most of an alternation of the oscillator. Taking into account the frequency of 4 Hz of the latter, the brevity of the stop of this second hand is not perceived and its movement appears as continuous for an observer.
• FIG. 1 is a block diagram illustrating the static state representative of an embodiment of the method which is the subject of this invention
• FIGS. 2-4 are block diagrams illustrating three dynamic states succeeding each other during a half-period of the oscillating regulator according to the embodiment shown in Figure 1
• Figures 5-8 are plan views of an embodiment of an exhaust mechanism for the implementation of this method illustrated through four successive phases
• Figures 9-16 are relative block diagrams to eight other variants of the mode of implementation of the method represented in FIGS. 1-4.
• compression is exerted on a leaf spring L, the two ends A and C of which are fixed by recesses Kl, respectively K2.
• the distance separating these two recesses Kl, K2 is such that the leaf spring L shows buckling. Thanks to a pair of middle supports J, this leaf spring L is forced to deform according to a buckling of second mode characterized in that the deformation of this leaf spring L has two bellies on either side of an inflection point I located near the pair of middle supports J.
• this leaf spring L there are exerted on this leaf spring L two forces NI, N2 generated by a driving source S.
• These forces NI, N2 are of equal intensities but in opposite directions and their points of application on the leaf spring L are symmetrical with respect to the point of inflection I. Thanks to the action of these two forces NI, N2, the leaf spring L is forced to leave its stable state (mixed lines) corresponding to a buckling of second mode in favor of a metastable state (solid line) close to an unstable state (dotted lines) corresponding to a buckling of fourth mode.
• the leaf spring L switches spontaneously into a new stable position (solid line) corresponding to a buckling of second mode opposite to that shown in FIG. 1.
• the leaf spring L releases the energy accumulated during the first phase and communicates it to the oscillating regulator R by a torque M clearly more intense than the torque m necessary for the tilting of the second phase.
• a small fraction of this energy released by the leaf spring L is also used to produce two forces ni, n2 in order to unlock the organs for transmitting the energy supplied by the motor source S.
• the operation is identical and symmetrical to that which has just been described above. Thanks to the aforementioned unlocking, the energy of the driving source S deforms the leaf spring L in a metastable position close to an unstable position corresponding to a buckling of fourth mode, symmetrical to that illustrated in FIG. 2. Then, being destabilized by the kinetic energy of the oscillating regulator R, the leaf spring L returns to the stable position illustrated in FIG. 1. This complete cycle of the leaf spring L therefore takes place while the oscillating regulator R performs an oscillation period.
• the fact of dissociating the energy pulses transmitted to the oscillating regulator R into two main phases of arming and expansion makes it possible to minimize the number of elements undergoing strong acceleration. lerations.
• the members located upstream of the leaf spring L in the kinematic chain participate in the winding phase and the members located downstream of the leaf spring L, in the expansion phase.
• the winding phase can take place over a much longer period than the expansion phase, only the inertia of the transmission member between the leaf spring L and the oscillating regulator R plays a significant role in the overall yield between the driving source S and the oscillating regulator R. Knowing that the friction forces increase according to the pressures in the bearings and that these same pressures depend, to a certain extent, on the accelerations undergone by the mobiles, one can expect that that a timepiece built using this process has better performance than a conventional construction.
• the oscillating regulator R of the exhaust mechanism intended to implement the method described above is constituted, in this example, by a balance 0 associated with a hairspring (not shown) as is known in most parts of mechanical watches and in particular in wristwatches. It is obvious that the present invention is not limited to this type of regulator.
• a plate 1 carrying a plate pin 1a is integral with the pendulum 0.
• This plate pin 1a is intended for periodically link the balance-spring oscillator with the exhaust mechanism itself.
• This mechanism comprises a trigger lever 2 secured to a rod 2f pivoting about an axis F.
• This trigger lever 2 comprises a fork made up of two horns 2a and 2c as well as a dart 2b. It is also formed of a tail 2h and lateral bulges carrying two ankles 2d and 2g which project perpendicularly to the plane of the trigger lever 2.
• a lever lever 3 secured to a rod 3e pivoting about an axis E.
• This armature rocker consists of a central body and two symmetrical lateral arms and carrying at their ends key-pin pairs 3g, 3d similar to those encountered on the rackets for hairsprings and which protrude perpendicular to the plane of the winding lever 3.
• Each of the key-pin pairs is engaged with a portion of the leaf spring L which is housed there like a hairspring in a racket.
• the central body carries two exhaust pins 3a and 3c, of cylindrical shape with a flat surface comparable to that of the plate pin 1a.
• the orientation of these exhaust pins 3a, 3c is adjustable so that an adjustment of the locking explained below is made possible.
• the trigger 2 and arm 3 flip-flops have openings 2e, respectively 3f, allowing their rods 2f, respectively 3e, to reciprocally cross the other flip-flop and thus be able to pivot between identical lower and upper frames (not shown) .
• the leaf spring L is, in this embodiment, in compression between two recesses and its ends A, C are slightly offset relative to a straight line intercepting the axis E.
• the distance between the ends A and C is such that the leaf spring L undergoes a buckling of second mode corresponding to the position illustrated in FIG. 5.
• the pins 2d and 2g of the trigger lever 2 apply the point of inflection I of the leaf spring L against the rod 3e of the arm lever 3, thus leaving the leaf spring L free to rotate around this rod 3rd.
• the arm lever 3 pivoting around the axis E which is not exactly in the same plane as the ends A and C of the leaf spring L, the key-pin pairs 3g and 3d do not have actions perfectly symmetrical on the leaf spring L. Given that the distance separating the key-pin pairs 3g, respectively 3d, from the axis E is clearly greater than the radius of the rod 3e against which the leaf spring L rests, effects of this asymmetry are negligible.
• Two escape wheels 4, 5 integral with escape pinions 6, respectively 7, pivoting around the axes D, respectively G, are arranged symmetrically with respect to a plane passing through the axes of rotation B of the pendulum O and of the plate 1 , E of the lever rocker 3, F of the trigger lever 2 and the point of inflection I of the leaf spring L.
• the exhaust pinions 6, 7 mesh with the last moving part of the gear train constituted by the wheel 8 secured to the pinion 9 pivoting about the axis H.
• the latter mobile is driven by the second mobile formed by the wheel 10 secured to a pinion (not shown) rotating at the rate of 1 revolution per minute in the center of the timepiece in case it displays the second at its center.
• each escape wheel 4, 5 is angularly divided into eight equal sectors, each of which comprises a winding cam 4b, respectively 5b, ending in a locking stop 4a, respectively 5a.
• These cocking cams 4b, 5b as well as these locking stops 4a, 5a are intended to cooperate alternately with the cocking lever 3, by means of the dowel pins. exhaust 3c, respectively 3a as will be explained below.
• the number of divisions of the escape wheels 4, 5 is in particular a function of the desired frequency at the level of the balance-spring oscillator. We know that it is all the less influenced by external disturbances the higher its frequency, which is why the escape wheels 4, 5 have been divided into eight equal sectors. These eight sectors theoretically allow the escapement to operate at frequencies of up to 57,600 vibrations per hour (Alt / h) while maintaining a gear ratio between the 10 seconds wheel and the pinions of exhaust 6, 7 not exceeding 60. In practice, this frequency has been limited to 28,800 Alt / h inducing a gear ratio between the second and exhaust mobiles of 30. This low gear ratio allows benefit from a large number of teeth at the exhaust pinions 6 and 7.
• the choice fell on 25 teeth, a number which is not a multiple of the eight sectors of the exhaust wheels 4 and 5.
• the orientation of the exhaust mobiles relative to one another can only be affected by a sector error of 4/25 th during their mounting in the timepiece.
• FIG. 5 represents the escape mechanism at the moment when the trigger lever 2 has just turned by an angle ⁇ 0 around the axis F and strikes the plate pin 1a via horn 2a.
• the tilting of the leaf spring L generating this pulse also causes a slight rotation of the winding lever 3 by an angle ⁇ 0 around the axis E via the key-pin pairs 3d and 3g.
• the exhaust pin 3c leaves a locking stop 4a and the exhaust pin 3a bears against a winding cam 5b.
• the plan views illustrated in Figures 6-8 show the chronology of the functions of the escapement mechanism during alternation of the O pendulum.
• the plan view illustrated in FIG. 6 represents the escape mechanism in its winding phase while the rotation ⁇ i of the plate 1 is reversed; the kinetic energy contained in the pendulum O is then completely transformed into mechanical energy by elastic deformation of the hairspring (not shown).
• the escape wheels 4, 5 rotate angles ⁇ i, respectively ⁇ x around the axes D, respectively G. While the escape wheel 4 turns freely, the escape wheel 5, by means of its cam armament 5b in contact with the cylindrical portion of the exhaust pin 3a, produces a rotation of the armament rocker 3 by an angle ⁇ i about the axis E.
• the couples key-pin 3d and 3g produce two opposite forces, identical and symmetrical with respect to the point of inflection I on the leaf spring L.
• the plan view illustrated in FIG. 7 represents the escape mechanism in its locking phase while the plate 1 has rotated by an angle ⁇ 2 around the axis B; almost all of the mechanical energy contained by elastic deformation of the hairspring has been transformed into kinetic energy contained in the pendulum O.
• the escapement wheels 4, 5 have completed their rotations of axes D, respectively G, by the angles ⁇ 2 , respectively ⁇ 2 .
• This stop occurs when a locking stop 5a comes into contact with the flat portion of the exhaust pin 3a.
• the winding lever 3 rotated around the axis E by an angle ⁇ 2 such that the key-pin pairs 3d and 3g forced the leaf spring L to continue winding from the intermediate state to a metastable state close to an unstable state corresponding to a buckling of fourth mode.
• the plan view illustrated in FIG. 8 represents the escape mechanism in its expansion phase while the kinetic energy contained in the pendulum O just begins to transform into mechanical energy by elastic deformation of the hairspring.
• the plateau pin la was close to coming into contact with the horn 2a of the trigger lever 2, here, the plateau pin loses contact with the horn 2c of the detent lever 2. It is during this short period of time that the pendulum O and the plate 1 travel through their lifting angle ⁇ 3 corresponding to the complement of the additional angle, the sum of these equivalent to alternation (two oscillation amplitudes).
• the start of the lifting angle ⁇ 3 corresponds to the release function.
• the pendulum O is the driving element and the plateau pin strikes the horn 2a of the trigger lever 2.
• the latter pushes the leaf spring L via the pin 2d so that it may exceed its unstable state thus marking the end of the release.
• the lifting angle ⁇ 3 continues with the pulse function during which the leaf spring L is the driving element. This suddenly switches from its unstable position to a stable state corresponding to a buckling of second mode opposite to that shown in FIG. 5.
• This tilting is transmitted on the one hand to the key-pin pairs 3d and 3g which rotate with the rocker of reinforcement 3 by an angle ⁇ 3 around the axis E and on the other hand at the 16 provided with a dart 2b.
• this dart 2b as well as the small plate integral with the plate 1 prevent the trigger lever 2 from inadvertently pivoting towards the other stable position while the pendulum 0 travels its angle additional.
• the trigger lever 2 is of course released in rotation since its dart 2b no longer abuts against the small plate thanks to the notch lb.
• the winding lever 3 is, in turn, dimensioned in such a way that its center of gravity is located on the axis of rotation E. Perfect balancing can be obtained by varying the diameter of the hole 3b located at the end of the central body, near the exhaust pins 3a and 3c.
• the winding lever 3 therefore benefits from the same impact safety and the expansion phase can effectively only occur once the notch lb of the plate 1 opposite the dart 2b of the trigger lever 2
• the escape mechanism described above contains compromises which it is more advantageous to adopt in the case of an application to the wristwatch. If such a mechanism is integrated into a larger timepiece such as a marine chronometer or a clock, it 17
• FIGS. 9-16 show this and can be easily compared to the diagram illustrated by FIG. 2.
• the mode of implementation illustrated by FIG. 9 differs only from that illustrated by FIG. 2 by the fact that the pair of median supports J is replaced by a median pivot member P secured to the leaf spring L at its point of inflection I.
• compression is exerted on the leaf spring L whose end A is 15 city 2g which rotates with the trigger lever 2 by an angle ⁇ 3 around the axis F.
• the rotation of the arm lever 3 causes the escape wheel 5 to be unlocked and ends when the pin d exhaust 3c comes into contact with the winding cam 4b of the escape wheel 4.
• the rotation of the trigger lever 2 makes it possible to communicate the energy contained in the leaf spring L to the balance O by the middle of the horn 2c striking the plateau pin la.
• the expansion phase ends when the opening 2e of the trigger lever 2 abuts against the rod 3e of the arm lever 3.
• the description of the exhaust mechanism above only explained its operation in the absence of external disturbance. Its application to the wristwatch or even to the pocket watch requires that it be able to function in the presence of shocks. To this end, the following measures have been taken so that this exhaust mechanism meets the requirements for operation in disturbed environments.
• the trigger lever 2 is fixed by a recess Kl and the end C is held by a pivoting member P2.
• the distance separating this embedding Kl from this pivoting member P2 is such that the leaf spring L shows a buckling of first mode characterized by the fact that its deformation has only one belly.
• the mode of implementation illustrated by FIG. 11 differs only from that illustrated by FIG. 2 by the fact that the ends A, C of the leaf spring L are not fixed in recesses Kl, K2 but held by members of pivoting PI, respectively P2.
• the winding phase of the leaf spring L can be carried out either using two forces NI, N2 as in the case of FIG. 2, or using two couples Ql, respectively Q2 of direction and d '' identical intensities acting on the ends A, respectively C of the leaf spring L and generated by the driving source S.
• the mode of implementation illustrated by FIG. 12 differs only from that illustrated by FIG. 11 by the fact that the pair of median supports J is replaced by a median pivoting member P secured to the leaf spring L at its point of inflection I.
• the winding phase of the leaf spring L can be carried out either using a force N as in the case of FIG. 10, or using a couple Q acting on the end A of the leaf spring L and generated by the driving source S.
• FIGS. 14, 15 and 16 differ only from those illustrated respectively by FIGS. 11, 12 and 13 by the fact that the ends A, C of the leaf spring L are no longer held by the members pivot PI, respectively P2 but are housed in supports Jl, respectively J2. As the ends A, C of the leaf spring L are no longer connected to any member whatsoever, the winding phase is preferably carried out using forces in accordance with Figures 2, 9 and 10.

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• 1999
  • 1999-05-14 EP EP99918207A patent/EP1084459A1/de not_active Withdrawn
  • 1999-05-14 WO PCT/IB1999/000870 patent/WO1999064936A1/fr not_active Application Discontinuation
  • 1999-05-14 AU AU36227/99A patent/AU3622799A/en not_active Abandoned

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