EP3070537A1 - Time base comprising an escapement with direct pulse and constant force - Google Patents

Abstract

The invention relates to a time base comprising a rocker associated with an escapement comprising an escapement wheel (2), kinematically connected to a source of mechanical energy, and an anchor (6) comprising
a pair of vanes (16, 17) for cooperating with the escape wheel (2) and
a fork (18) for cooperating with a plateau pin (20) carried by a rocker plate (24),
the balance carrying an additional plate (30) carrying a pulse pallet (32) for receiving pulses from the exhaust. The latter comprises a pulse wheel (4) coaxial with the escape wheel (2) and arranged to cooperate with the pulse pallet (32) to ensure the maintenance of oscillations of the balance wheel, the escape wheels ( 2) and pulse (4) having respective teeth having the same number of teeth and being connected to each other by an elastic return member, the anchor (6) having an additional pair of pallets (28). 29) arranged to cooperate with the impulse wheel (4).

Description

Technical area

The present invention relates to a time base, for a watch movement, comprising a balance associated with a return member arranged in such a way that the balance is able to perform periodic oscillations around a balance axis, the balance being associated with an exhaust comprising
an escape wheel, intended to be kinematically connected to a source of mechanical energy of the watch movement, and
an anchor comprising, on the one hand, a pair of vanes arranged to cooperate with the escape wheel and, on the other hand, a fork arranged to cooperate with a plateau pin carried by a pendulum plate integral in rotation with the balance wheel ,
the balance being further secured to an additional balance plate carrying a pulse pallet for periodically receiving pulses of the exhaust.

State of the art

Time bases of this type, direct impulse, have been known for a long time even if they are not widespread in mechanical timepieces sold today.

For example, the patent CH101849 , issued in 1923 in the name of Jules Pellaton, describes a particular realization. Indeed, this document describes a time base comprising a sprung balance associated with a direct impulse escapement comprising an escape wheel, connected to a barrel via a finishing train, and an anchor carrying two pallets. , an input and an output, arranged to cooperate alternately with the escape wheel. The balance is secured to a conventional balance plate carrying a plate pin cooperating with a fork of the anchor to rotate the latter at each alternation of the balance. In addition, the balance is also secured to an additional tray carrying a pallet pulse, also arranged to cooperate with the escape wheel, for the purpose of receiving a pulse directly from the latter during a pulse alternation, that is to say every alternate alternation.

However, even if the impulse for maintaining the oscillations of the sprung balance is transmitted directly from the escape wheel to the additional plate of the balance, thus presenting a better yield than the escapements in which the impulse is transmitted through the anchor, its value depends on the state of charge of the mainspring whose torque can vary significantly between its minimum and maximum load states.

Disclosure of the invention

A main object of the present invention is to propose a time base, for a watch movement, whose oscillation frequency is independent of the state of charge of the source of mechanical energy from which it receives the energy to ensure the maintenance of oscillations.

For this purpose, the invention relates more particularly to a time base, for a watch movement, of the type mentioned above, characterized
in that the escapement comprises a pulse wheel coaxial with the escape wheel and arranged to cooperate with the pulse pallet, during pulse alternations, to ensure the maintenance of oscillations of the pendulum, the escape and impulse wheels having respective teeth having the same number of teeth and being connected to one another by an elastic return member, and
in that the anchor comprises an additional pair of pallets arranged to cooperate with the impulse wheel.

Thanks to these characteristics, the pulse is transmitted to the balance from the energy stored in the elastic return member, which is independent of that stored in the main mechanical energy source of the watch movement, thus leading to an exhaust constant force type.

Indeed, at each oscillation of the balance, the elastic return member discharges a small amount of energy, when the pulse wheel is released to transmit a pulse to the pulse pallet, but is immediately reloaded with the same amount of energy, by rotating the escape wheel at the same angle as that traveled by the impulse wheel.

In addition, the impulse wheel has a reduced inertia with reference to the escape wheel, because it does not carry a pinion and is not in contact with the finishing gear, which allows it to limit the disturbances due to its interaction with the pendulum.

In a preferred manner, safety devices guaranteeing the reliability of the time base according to the present invention can be provided. Thus, it preferably comprises two limiting pins arranged on either side of a rod of the anchor to define an angular range of rotation of the anchor. In addition, it is advantageous that the anchor carries a sting capable of cooperating with the periphery of the balance plate to prevent a reversal, the balance plate having a notch arranged to allow periodically the passage of the stinger from one side to the other. other of the line joining the pivot axes of the anchor and the balance plate.

Advantageously, it can be provided, on the one hand, that the vanes are arranged relative to the escape wheel and, on the other hand, that the additional vanes are arranged relative to the impulse wheel so that the impulse wheel is released before the escape wheel during pulse alternations.

In addition, it can also be provided that, on the one hand, the pallets are arranged relative to the escape wheel and, on the other hand, the additional pallets are arranged relative to the impulse wheel in such a way that the wheel Exhaust is released during the pulse alternations after the pulse pallet has crossed the line joining the pivot axes of the impulse wheel and the balance plate.

According to a preferred embodiment, the vanes are arranged relative to the escape wheel so that the latter performs a rotation of a half-step at each alternation.

In general, it can be provided that the additional pallets are arranged relative to the impulse wheel in such a way that, in one oscillation, the impulse wheel travels at a higher rotational angle, preferably four times higher, when alternation of impulse than that which it traverses during the complementary alternation.

Advantageously, it can be provided that the additional pair of pallets comprises an entry pallet and an exit pallet, the exit pallet being shaped in such a way that the impulse wheel transmits an impulse when it is released at course of the alternation complementary to the alternation of impulse.

The invention also relates to a watch movement comprising a time base meeting the characteristics just described and a timepiece equipped with such a watch movement.

Brief description of the drawings

• la figure 1 représente une vue de dessus simplifiée d'une base de temps selon un mode de réalisation préféré de l'invention, dans un premier état;
• la figure 2 représente une vue de dessus simplifiée de la base de temps de la figure 1, dans un deuxième état;
• la figure 3 représente une vue de dessus simplifiée de la base de temps de la figure 1, dans un troisième état;
• la figure 3a représente un détail de la vue de la figure 3;
• la figure 4 représente une vue de dessus simplifiée de la base de temps de la figure 1, dans un quatrième état;
• la figure 5 représente une vue de dessus simplifiée de la base de temps de la figure 1, dans un cinquième état;
• la figure 6 représente une vue de dessus simplifiée de la base de temps de la figure 1, dans un sixième état;
• la figure 7 représente une vue de dessus simplifiée de la base de temps de la figure 1, dans un septième état;
• la figure 8 représente une vue de dessus simplifiée de la base de temps de la figure 1, dans un huitième état;
• la figure 9 représente une vue de dessus simplifiée de la base de temps de la figure 1, dans un neuvième état;
• la figure 9a représente un détail de la vue de la figure 9, et
• la figure 10 représente une vue de dessus simplifiée de la base de temps de la figure 1, dans un dixième état.

Other features and advantages of the present invention will appear more clearly on reading the detailed description of a preferred embodiment, with reference to the accompanying drawings given by way of non-limiting example and in which:

• the figure 1 represents a simplified top view of a time base according to a preferred embodiment of the invention, in a first state;
• the figure 2 represents a simplified top view of the time base of the figure 1 in a second state;
• the figure 3 represents a simplified top view of the time base of the figure 1 in a third state;
• the figure 3a represents a detail of the view of the figure 3 ;
• the figure 4 represents a simplified top view of the time base of the figure 1 in a fourth state;
• the figure 5 represents a simplified top view of the time base of the figure 1 in a fifth state;
• the figure 6 represents a simplified top view of the time base of the figure 1 in a sixth state;
• the figure 7 represents a simplified top view of the time base of the figure 1 in a seventh state;
• the figure 8 represents a simplified top view of the time base of the figure 1 in an eighth state;
• the figure 9 represents a simplified top view of the time base of the figure 1 in a ninth state;
• the figure 9a represents a detail of the view of the figure 9 , and
• the figure 10 represents a simplified top view of the time base of the figure 1 in a tenth state.

Mode (s) of realization of the invention

According to the preferred embodiment of the invention, as illustrated in particular by the figures, the time base comprises a spiral balance (not shown) associated with a constant force and direct impulse type escapement.

The time base here comprises two coaxial escapement wheels, one of which will be called the escape wheel 2 and the second will be called the impulse wheel 4. The two wheels 2 and 4 have the same number of teeth and substantially the same diameter of teeth.

The escape wheel 2 carries an exhaust pinion (not visible) intended to be kinematically connected to a source of mechanical energy of a watch movement via a finishing train.

The impulse wheel 4 is connected to the escape wheel 2 by means of an elastic return member, for example a spiral spring (not visible).

A double anchor 6 is associated with the two wheels 2 and 4.

The anchor 6 is intended to be pivotally mounted on the frame of the watch movement, along an axis of rotation defined by a span screw 8 housed in a suitable hole of the anchor 6. It comprises a base 10 having a rod 12 arranged between two limit pins 14, intended to be assembled to the frame of the watch movement, to define a range of rotation of the anchor 6. Typically, the range of rotation of the anchor 6 may be of the order of a few degrees, preferably about 3 degrees.

The base 10 carries a first pair of vanes, including an entry pallet 16 and an outlet pallet 17, arranged on either side of the axis of rotation of the anchor to cooperate with the escape wheel 2 .

Furthermore, the base 10 also comprises a fork 18, at its free end opposite the rod 12, arranged to cooperate with a plate pin 20. The plate pin 20 is housed in a hole 22 formed in a plate 24 integral with rotation of the balance.

By way of nonlimiting illustration, the hole 22 is made here in a manner similar to an anchor cell, that is to say that it extends in a radial direction with reference to the plate 24, so that the Tray pin 20 may have a portion arranged radially projecting with reference to the hole 22 in order to periodically cooperate with the fork 18 and pivot the anchor 6.

More specifically, the plate 24 has a generally cylindrical shape delimited by two substantially flat faces, the hole 22 being open on at least one of the two faces, so that a tool can be inserted between the plate pin 20 and the bottom of the hole 22, to be able to easily act on the plate pin 20, if necessary, and push it out of the hole 22 to increase the length of its projecting portion.

The plate pin 20 further has a symmetrical shape with reference to a median radial plane of the hole 22, to cooperate equivalently with the fork 18 regardless of the direction of rotation of the balance. The plate pin 20 has an end portion (outer) whose width is greater than that of the hole 22, but slightly smaller than that of the fork 18 of the anchor 6.

Furthermore, the anchor 6 comprises an additional base 26 carrying a second pair of vanes, including an entry pallet 28 and an outlet pallet 29, arranged to cooperate with the toothing of the impulse wheel. 4. The relative orientation of the additional base 26 on the base 10 is preferably adjustable.

The first and second pairs of vanes 16, 17, 28, 29, on the one hand, and the teeth of the wheels 2, 4, on the other hand, are arranged in such a way that the vanes 16, 17 of the first pair cooperate. with the escape wheel 2 and the pallets 28, 29 of the second pair cooperate with the impulse wheel 4 with a slight time shift. The kinematics of the exhaust will be explained in detail in the following description.

In addition, the balance is rotatably connected to an additional plate 30 carrying a pulse pallet 32 arranged to cooperate with the toothing of the pulse wheel 4. Thus, the pulse pallet 32 receives a pulse from the wheel pulse 4 all the alternation of the pendulum out of two. This pulse is therefore direct, from the impulse wheel 4 to the balance, and therefore has a better efficiency than in the case of an impulse transmitted via an anchor.

Note also that the plate 24 advantageously comprises a notch (not visible) arranged to cooperate with a dart 34 (shown in FIG. figure 5 ) carried by the anchor 6 to prevent a reversal of the exhaust, in known manner.

The operating kinematics of the time base according to the present invention will be explained in detail in connection with the figures which illustrate a complete oscillation of the balance spring in a chronological order.

The figure 1 illustrates a first state in which the anchor 6 abuts against one of the limiting pins 14.

The escape wheel 2 rests on the entry pallet 16 by one of its teeth, while the impulse wheel 4 rests on the additional entry pallet 28 by one of its teeth.

The sprung balance rotates counter-clockwise, as indicated by the arrow F1.

The figure 2 illustrates the following state, corresponding to the input of the plate pin 20 in the fork 18 to pivot the anchor 6, the latter being always disposed in abutment against the limiting pin 14 in the state illustrated on the figure 2 .

Note the particular geometry of the plate pin 20 and the horns of the fork 18, slightly beveled inwards, which allows to have a relatively small range of rotation of the anchor 6, preferably of the order of 3 degrees as mentioned above.

Once entered in the fork 18, the plateau pin 20 acts on the tooth of the fork located downstream, as is apparent from the view of the figure 3 , to begin to rotate the anchor 6 in the clockwise direction.

Meanwhile, the impulse pallet 32 is passed past a tooth of the impulse wheel 4 without touching it, in a position that allows it to receive a pulse.

The figure 3a illustrates a detail of the representation of the figure 3 , more precisely the positions of the entry pallets 16 and 28 in relation to the wheels 2 and 4.

It appears that the additional entry pallet 28 is about to release the impulse wheel 4, while the entry pallet 16 still holds the escape wheel 2.

When the impulse wheel 4 is released, as illustrated on the figure 4 , it starts to rotate in the direction of clockwise rotation under the effect of the action of the elastic return member arranged between it and the escape wheel 2. One of its teeth then comes into contact with the pulse pallet 32 of the additional balance plate 30 to transmit a pulse to maintain the periodic oscillations of the sprung balance.

The escape wheel 2 remains locked by the entry pallet 16 during this phase.

The rotation of the impulse wheel 4 continues, as is apparent from the figure 5 , while the escape wheel 2 remains locked. Thus, the tooth of the impulse wheel 4 accompanies the impulse pallet 32 to cross the line joining the pivot axes of the anchor 6 and the balance plate 20. It follows that the impulse is direct from the impulse wheel 4 to the pendulum, that the impulse has limited losses, because of its duration, and only depends on the characteristics of the resilient return member connecting the impulse wheel 4 to the escape wheel 2, ensuring the transmission of a constant force to the pendulum.

The state illustrated on the figure 5 corresponds to the instant at which the escape wheel 2 is released by the entry pallet 16 of the anchor 6.

At the same time, the plateau pin 20 comes out of the fork 18.

Furthermore, the stinger 34 of the anchor 6 crosses the line joining the pivot axes of the anchor 6 and the balance plate 24 at this time, thanks to the notch (not visible) of the plate 24.

In its rotation, the anchor 6 has modified the position of the output vanes 17 and 29, to place them on the path of the wheels 2 and 4, as illustrated in FIG. figure 6 .

While the sprung balance continues to rotate in the direction of rotation anti-clockwise, the two wheels 2 and 4 are at rest on the pallets output 17 and 29.

A comparative view of the states of figures 1 and 6 shows that the escape wheel 2 has rotated a half-step during the pulse alternation that has just been described, while the impulse wheel has performed about 4/5 ^th to not.

Once the maximum amplitude has been reached, the sprung balance reverses its direction of rotation in order to turn in the clockwise direction during the alternation complementary to the pulse alternation, as illustrated in FIG. figure 7 by the arrow F2.

The position of the impulse wheel 4 in this state is such that the impulse pallet 32 can pass in front of its nearest teeth without coming into contact with them.

The plateau peg 20 begins to enter the fork 18 at this time, as shown in FIG. figure 8 , a short moment after the one shown on the figure 7 .

The figure 8 represents the moment at which the plate pin 20 comes into contact with one of the horns of the fork 18 to begin to pivot the anchor 6 in the anti-clockwise direction of rotation.

When the anchor 6 pivots, as illustrated on the figure 9 , the output vanes 17 and 29 begin to move away from the wheels 2 and 4 to release them.

The moment just before the release of wheels 2 and 4 is shown in detail on the figure 9a , which illustrates an enlargement of the output vanes 17 and 29 while they are still in contact with the wheels 2 and 4.

It is particularly apparent from the figure 9a that the additional output pallet 29 is shaped such that the impulse wheel transmits a pulse, shown schematically by the arrow F3, when released during the alternation complementary to the pulse alternation. More specifically, the output pallet 29 has the impulse wheel 4 an outlet face 36 whose inclination is inverted with reference to the direction of inclination provided on the other pallets. Due to this inverted inclination of the output face 36, the tooth of the impulse wheel 4 exerts a slight force on the additional output pallet 29 when the impulse wheel 4 is released and begins to rotate. Note, however, that this pulse is low and essentially useful when starting the oscillations of the sprung balance or when the latter oscillates with a small amplitude.

The escape wheel 2 is released by the output pallet 17 during the pulse phase of the impulse wheel 4 to the additional output pallet 29.

The figure 10 illustrates the next moment, when the impulse wheel 4 finally leaves the additional output pallet 29, immediately after the release of the escape wheel 2.

By pivoting, the anchor 6 has brought the input vanes 16 and 28 on the path of the teeth of the wheels 2 and 4 which then travel lost paths. The escape wheel 2 travels a half-step before its next tooth makes contact with the entry pallet 16, while the impulse wheel 4 travels a fifth of a step before its next tooth enters in contact with the additional entry pallet 28.

The sprung balance continues to rotate in the clockwise direction up to the maximum amplitude, at the end of alternation complementary to the pulse alternation, before changing direction of rotation and turning in the anti-clockwise direction, to return to the state shown on the figure 1 and start a new oscillation.

With the present invention, it is possible to achieve a precise time base, by the use of a constant force escapement, and having a good efficiency, by the implementation of a direct pulse.

The escape wheel 2, defining the rotation rate of the mobile of the work train and therefore the display members performs a half-step at each alternation, which advantageously results in a regular displacement of the display members.

In addition, having a total angle traveled by the anchor, a limiting pin to the other, which is low, preferably of the order of 3 degrees, can limit the disturbances that apply to the pendulum when passing from the plateau peg into the anchor fork.

Finally, thanks to the construction of the escapement, in particular the particular shape of the additional output pallet, the oscillations of the sprung balance can be restarted easily from a stopped state, as soon as the main mechanical energy source starts to be recharged. Typically, the main source of mechanical energy may be a barrel housing a spring and it is sufficient in this case a few turns of winding crown to restart the oscillations of the sprung balance.

The foregoing description attempts to describe a particular embodiment by way of non-limiting illustration and the invention is not limited to the implementation of certain particular features which have just been described, for example the forms specifically illustrated and described for the escape wheels and for the anchor, as well as for the balance plates, the plateau pin or its housing in the balance plate.

The skilled person will not encounter any particular difficulty to adapt the content of the present disclosure to his own needs and to realize a time base comprising an impulse escapement direct and constant force, without departing from the scope of the present invention.

Claims (10)

Time base, for a watch movement, comprising a balance associated with a return member arranged in such a way that said balance is capable of performing periodic oscillations around a balance axis, said balance being associated with an escapement comprising
an escape wheel (2), intended to be kinematically connected to a source of mechanical energy of the watch movement, and
an anchor (6) comprising, on the one hand, a pair of vanes (16, 17) arranged to cooperate with said escape wheel (2) and, on the other hand, a fork (18) arranged to cooperate with a plate peg (20) carried by a rocker plate (24) integral in rotation with said beam,
said balance being further secured to an additional balance plate (30) carrying a pulse pallet (32) for periodically receiving pulses of said exhaust,
characterized
in that said escapement comprises a pulse wheel (4) coaxial with said escape wheel (2) and arranged to cooperate with said pulse pallet (32), during pulse alternations, to ensure maintenance of oscillations of said balance wheel, said escape wheels (2) and impulse wheels (4) having respective teeth having the same number of teeth and being connected to one another by an elastic return member, and
in that said anchor (6) comprises an additional pair of vanes (28, 29) arranged to cooperate with said impulse wheel (4). Time base according to claim 1, characterized in that it comprises two limiting pins (14) arranged on either side of a rod (12) of said anchor (6) to define an angular range of rotation of said anchor (6). Time base according to claim 1 or 2, characterized in that said anchor (6) carries a dart (34) capable of cooperating with the periphery of said balance plate (24) to prevent a reversal, said balance plate (24) having a notch arranged to allow periodically passing said dart (34) from one side to the other of the line joining the pivot axes of said anchor (6) and said rocker plate (24). Time base according to one of the preceding claims, characterized in that , on the one hand, said pallets (16, 17) are arranged relative to said escape wheel (2) and, on the other hand, said additional pallets (28, 29) are arranged relative to said impulse wheel (4) such that said impulse wheel (4) is released before said escape wheel (2) during pulse alternations. Time base according to claim 4, characterized in that , on the one hand, said pallets (16, 17) are arranged relative to said escape wheel (2) and, on the other hand, said additional pallets (28, 29) are arranged relative to said impulse wheel (4) such that said escape wheel (2) is released during pulse alternations after said impulse pallet (32) has passed the impulse wheel (4). line joining the pivot axes of said impulse wheel (4) and said rocker plate (24). Time base according to one of the preceding claims, characterized in that the said vanes (16, 17) are arranged relative to the said escape wheel (2) in such a way that the said escape wheel (2) carries out a rotation of half a step at each alternation. Time base according to one of the preceding claims, characterized in that said additional pallets (28, 29) are arranged relative to said impulse wheel (4) in such a way that, in an oscillation, said impulse wheel ( 4) traverses a higher rotation angle, preferably four times higher, during the pulse alternation than that it travels during the complementary alternation. Time base according to one of the preceding claims, characterized in that said pair of additional pallets (28, 29) comprises an inlet pallet (28) and an outlet pallet (29), said pallet outlet (29) being shaped in such a way that said impulse wheel (4) transmits an impulse when it is released during the alternation complementary to the pulse alternation. Watch movement comprising a time base according to one of the preceding claims. Timepiece comprising a watch movement according to claim 9.

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