This application claims priority from European Patent Application No 15179711.5 filed Aug. 4, 2015, the entire disclosure of which is hereby incorporated herein by reference.
The invention concerns a timepiece regulating mechanism comprising a plate and, mounted to move at least in a pivoting motion with respect to said plate, an escape wheel set that pivots about an axis of escapement and is subjected to a drive torque, and at least a first resonator comprising a first rigid structure connected to said plate by first elastic return means, said first rigid structure carrying at least one inertia arm including a first inertia arm arranged to cooperate with said escape wheel set via magnetically and/or electrically charged tracks comprised in both said at least one first inertia arm and said escape wheel set, to form a synchronizing device between said escape wheel set and said at least one first resonator.
The invention also concerns a timepiece movement comprising at least one such regulating mechanism.
The invention also concerns a timepiece comprising such a movement or such a regulating mechanism.
The invention concerns the field of timepiece regulating mechanisms, particularly timepiece escapement mechanisms, and more specifically the field of contactless escapements.
The mechanical watch movement that we know today is the result of successive improvements over the last three centuries. The Swiss lever escapement is characterized by its robustness to shocks. That is to say that the state of the watch is little affected by a one-off shock.
However, the efficiency of such an escapement is not very good (around 30%). Moreover, the Swiss lever escapement does not permit the use of resonators with a high frequency or low amplitude.
Ways are therefore sought to use resonators having a high quality factor, a high frequency, and/or low amplitude, while increasing the efficiency of the escapement and without sacrificing its robustness to shocks.
Among the embodiments relating to the field of the invention, the following are known:
the tuning fork clock developed by Clifford;
the Resonique® movement developed by De Bethune®,
the Accutron® watch developed by Bulova®.
Each of these embodiments offers particular advantages, but these movements have the same drawback: they are not resistant to shocks. That is to say that, in the event of a shock, the hands rapidly gain time.
EP Patent Application 2889704A2 in the name of Nivarox-FAR SA discloses a timepiece escapement mechanism, comprising an escape wheel subjected to a rotational torque, having a moment of inertia lower than or equal to a nominal moment, about a first pivot axis, and a resonator integral with a regulating wheel set mounted to pivot about a second real or virtual pivot arbor/axis, said escape wheel comprising a plurality of actuators regularly spaced on its periphery and each arranged to cooperate directly with at least a first track of said regulating wheel set, characterized in that each said actuator includes first magnetic or electrostatic stopping means forming a barrier, and arranged to cooperate with said first track which is magnetically, or respectively electrically charged, or ferromagnetic, or respectively electrostatically conductive, to exert on said first track a torque having a moment greater than said nominal moment, and further characterized in that each said actuator also includes second stopping means arranged to form an end-of-travel stop, arranged to form an autonomous escapement mechanism with at least a first complementary stop surface comprised in said regulating wheel set.
WO Patent Application 2015/096979A2 in the name of The Swatch Group Research & Development Ltd discloses a timepiece escapement mechanism comprising a stop member between, on the one hand, a resonator, and on the other hand, two escape wheel sets each subjected to a torque, characterized in that each said escape wheel set comprises at least one magnetized or ferromagnetic, or respectively, electrically charged or electrostatically conductive track with a period of travel over which its magnetic, or respectively, electrostatic characteristics are repeated, said stop member including at least one magnetized or ferromagnetic, or respectively, electrically charged or electrostatically conductive pole piece, said pole piece being mobile in a transverse direction relative to the direction of travel of at least one element on a surface of said track, and at least said pole piece or said track creating a magnetic or electrostatic field in an air-gap between said at least one pole piece and said at least one surface, and further characterized in that said pole piece confronts a magnetic or electrostatic field barrier on said track just before each transverse motion of said stop member controlled by the periodic action of said resonator, and characterized in that said first escape wheel set subjected to a first torque and said second escape wheel set subjected to a second torque are each arranged to be capable of cooperating alternately with said stop member, and in that said first escape wheel set and said second escape wheel set pivot about distinct axes and are connected to each other by a direct kinematic connection.
U.S. patent application Ser. No. 3/183,426A in the name of HAYDON ARTHUR describes an entirely magnetic escapement including a magnetic escape wheel, in which the energy varies continuously and progressively between minimum and maximum when the wheel turns through one half-period and then the energy returns to a minimum value over the following half-period. In other words, the magnetic force on the wheel varies progressively between a minimum (negative) and maximum (positive) value over an angular period.
The invention proposes to remedy this shortcoming of the prior art, by developing a watch, notably a mechanical watch, provided with a regulator with magnetically synchronized rotating arms and equipped with a mechanical anti-desynchronization device.
To this end, the invention concerns a regulating mechanism according to claim 1.
The invention also concerns a timepiece movement comprising at least one such regulating mechanism.
The invention also concerns a timepiece including one such movement.
Other features and advantages of the invention will appear upon reading the following detailed description, with reference to the annexed drawings, in which:
The invention proposes to develop a mechanical regulating mechanism, comprising resonators having a high quality factor, a high frequency, and/or low amplitudes, while increasing the efficiency of the escapement and without sacrificing its robustness to shocks
This regulating mechanism is based on at least one magnetically or electrostatically synchronized oscillator. The invention is more specifically described in the magnetic case. Those skilled in the art may refer to the other Applications made by the same Applicant, incorporated herein by reference, which describe in more detail the elements of the magnetic synchronizing interaction, and which also concern the electrostatic variant:
European Patent Application EP 14182532.3
European Patent Application EP 13199428.7
European Patent Application EP 14176816.8
European Patent Application EP 14199040.8
European Patent Application EP 14199039.0
European Patent Application PCT/EP 2014/079036
European Patent Application EP 14186261.5
European Patent Application EP 14184155.1
European Patent Application EP 13199427.9.
Thus, the invention concerns a timepiece regulating mechanism 200 comprising a main plate 1 and, mounted to move at least in a pivoting motion relative to plate 1, an escape wheel set 10 and at least a first resonator 100.
Escape wheel set 10 is illustrated here in a non-limiting manner by an escape wheel. It pivots about an axis of escapement DO, and is subjected to a drive torque, from an accumulator such as a barrel or similar element.
At least a first resonator 100 comprises a first rigid structure 110, which is connected to plate 1 by first elastic return means 120. This first rigid structure 110 carries at least one inertia arm 130 or 140. It also carries, at the ends of arm 111, inertia weights 112 carrying inertia and poising adjustment screws 113.
According to the invention, the synchronizing device is protected from loss of synchronization when there is an accidental increase in torque by a mechanical anti-desynchronization mechanism comprising mechanical escapement stops 12 carried by escape wheel set 10, and by at least one mechanical inertia arm stop 132, carried by the at least one first inertia arm 130, and together arranged to maintain stopped in abutment in the same case of accidental torque increase.
More specifically, according to the invention, the at least one first inertia arm 130 pivots about a first virtual axis D1. And said mechanical inertia arm stops 132, comprised in inertia arm 130, each extend in a direction substantially tangent to the rotating oscillating travel of inertia arm 130 about first virtual axis D1.
More specifically, in the variant of
In the variant of
In a particular, non-limiting variant, illustrated by the Figures, the magnetically and/or electrically charged track comprised in the at least one first inertia arm 130 comprises alternately at least one first inertia arm pole piece 131A and a second inertia arm pole piece 131B, which extend on either side of a radial line R originating from first virtual axis D1, and on either side of a common perpendicular T to radial line R.
More specifically, in the variant illustrated in
More particularly, in these variants, the total dimensions, on radial line R, of a group formed by a consecutive first inertia arm pole piece 131A and second inertia arm pole piece 131B, along radial line R, is substantially equal to a linear pitch P which is the projection onto radial R of pitch angle α. The distance, along radial R, between the mechanical inertia arm stops 132 corresponding to the same group, is substantially equal to half of linear pitch P.
In an advantageous variant illustrated by
More specifically, the mechanical anti-desynchronization mechanism comprises at least one second mechanical inertia arm stop 142 carried by second inertia arm 140. However, the mechanism may operate with the single first stop of first arm 130.
As illustrated by the Figures, more specifically, first inertia arm 130 and second inertia arm 140 each include a fastening 133, respectively 143, for at least one flexible strip 135, respectively 145, the flexible strips 135, respectively 145, being attached at their other end to first rigid structure 110 formed by the same connecting piece 20, comprising a bending area 21, here of the type with neck portions, just at the point of rigid attachment to the plate, and secured to plate 1, in a end restraint 2.
The first inertia arm 130 and second inertia arm 140 are arranged to vibrate in phase opposition to each other. It is in this configuration that the quality factor is best
In the variant of
More specifically, at least one magnetically and/or electrically charged track comprised in escape wheel set 10 comprises alternate escapement pole pieces 11 and mechanical escapement stops 12 at the same pitch angle a, and, in each pair, the angular distance, in projection onto the same plane perpendicular to axis of escapement D0, between the inertia arm pole piece 131, 141, and the mechanical inertia arm stop 132, 142, is equal to half of pitch angle α.
More specifically, as illustrated, first inertia arm 130 and second inertia arm 140, and flexible strips 135, 145, extend in directions substantially parallel to each other, and orthogonal to that of connecting piece 20.
In a particular advantageous manner, each inertia arm 130, 140, is arranged to cooperate continuously with escape wheel set 10, with no periodic stopping of escape wheel set 10.
In a particular variant, as seen in
In a variant, the system of mechanical stops is coplanar and comprises at least one finger arranged to cooperate radially with a toothed wheel.
In a particular, low amplitude embodiment, the angular amplitude of each inertia arm 130, 140, is less than 20°.
More specifically, at least one of inertia arms 130, 140, of the tuning fork carries two magnetic pallet stones.
More specifically, the two inertia arms 130, 140, of the tuning fork each carry at least one magnetic pallet stone.
More specifically, at least one of the inertia arms 130, 140 of the tuning fork carries two mechanical anti-desynchronization pallet stones.
More specifically, the two inertia arms 130, 140, of the tuning fork each carry at least one mechanical anti-desynchronization pallet stone.
As seen in
More specifically, connecting piece 20 of the two tuning fork arms is connected to plate 1 by a viscoelastic or polyurethane component, arranged to dissipate reaction forces on the support due to a temporary “windscreen wiper” mode of the tuning fork when inertia arms 130, 140 have a substantially synchronous motion.
In another variant, connecting piece 20 of the two tuning fork arms is connected to plate 1 by a friction mechanism, coupled to a means of elastic return to a neutral or rest position, and arranged to dissipate reaction forces on the support due to a temporary “windscreen wiper” mode of the tuning fork when inertia arms 130, 140 have a substantially synchronous motion.
Advantageously, at least one component of the mechanical anti-desynchronization mechanism is made of a shock absorbent material, to avoid rebounds.
As seen in
In a particular variant, the mechanical anti-desynchronization mechanism comprises at least one set formed by a pallet stone of an inertial arm 130, 140, arranged to cooperate in a stop position with a pin of escape wheel set 10. The pallet stones and pins of the anti-desynchronization mechanism are arranged to intercept each other if escape wheel set 10 is forced to pivot, while the at least one first resonator 100 is maintained in its position of equilibrium.
In a particular, advantageous manner, first elastic return means 120 comprise at least one flexible strip made of oxidised silicon for thermal compensation of frequency variations.
In a particular variant, which is the easiest to implement, the synchronization is magnetic.
In a particularly advantageous application, regulating mechanism 200 forms a regulating and escapement mechanism.
The invention also concerns a timepiece movement 300 including at least one such regulating mechanism 200.
The invention also concerns a timepiece 400 comprising such a movement 300, or comprising at least one such regulating mechanism 200.
The advantage of the invention is that it makes it possible to reconcile the high efficiency offered by a magnetic synchronizing system (more than 90%), while eliminating its main defect, namely loss of synchronization in the event of high torque. Reliability is thus improved without impairing the efficiency performance.
The protection provided by this solution in the event of excessive torque is inexpensive and easy to combine with a magnetic or similar escapement.
Number | Date | Country | Kind |
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15179711.5 | Aug 2015 | EP | regional |