EP1562086B1 - Power reserve indicator mechanism - Google Patents

Abstract

The mechanism has an intermediate movable part (32) with two parts connected by a connection unit. The unit has a friction mechanism arranged such that one part can move with friction with respect to the other part when a power reserve indicator attains its end position and an elastic unit arranged such that it is reinforced when the indicator attains its another end position.

Description

The present invention relates to the field of watchmaking. It relates, more particularly, the power reserve indicator mechanisms for a timepiece movement of the type provided with a power source formed by a motor spring. Conventionally, the mechanism according to the invention comprises a frame, a power reserve indicator and a differential gear with a first input connected to a mobile driven in rotation during the winding of the mainspring and a second input connected to a mobile rotated during disarming of the mainspring, and an output connected to the power reserve indicator. In such a mechanism, the indicator is likely to traverse a given angle between two extreme positions, the first is occupied when the mainspring is armed and the second, when the spring is disarmed.

A mechanism of this type is described in "The Swiss automatic winding watch" by B. Humbert, editions Scriptar, Lausanne 1955, on page 85. It is equipped with a friction mounted indicator on a mobile connected to the output of the differential . The two extreme positions between which the indicator moves are defined by stops. When the indicator arrives at one of the stops, the upper limit of winding or disarming of the mainspring, it remains stationary while the mainspring continues to be armed or disarmed, the friction allowing the displacement of the gear while the indicator is fixed.

Such a solution therefore makes it possible to estimate the actual winding of the mainspring, but there may be significant differences from one cycle to another, due to the relative displacement of the indicator relative to the gear train.

To overcome this drawback, the demand for EP Patent 1,139,182 filed in the name of the applicant describes a mechanism comprising an intermediate mobile interposed between the output of the differential gear and the indicator of power reserve. This mobile comprises an elastic element arranged so that the differential gear continues to rotate freely while the indicator remains in abutment, resulting in the arming of the elastic element.

In practice, this arrangement is usable when the indicator is abutting in one or the other of its extreme positions. But it is difficult to make perfectly coincide the maximum arming position of the mainspring with the extreme position of the indicator corresponding to the largest power reserve. This implies special precautions and precise measurements during assembly, especially during after-sales service, for the indicator to display correct information.

The present invention aims to overcome the drawback mentioned above, while retaining the advantages presented by the mechanism of the EP application already cited.

• un indicateur de réserve de marche avec un mobile et un dispositif d'affichage porté par le mobile,
• un engrenage différentiel relié cinématiquement par une première entrée au barillet, par une seconde entrée aux moyens d'armage et par une sortie à l'indicateur, et
• un mobile intermédiaire comportant des première et deuxième parties respectivement reliées cinématiquement à la sortie et au mobile de l'indicateur et un organe de liaison reliant ces parties, agencé de manière à ce que l'indicateur occupe une position comprise entre deux positions extrêmes, la première atteinte lorsque l'armage du ressort est plus fort qu'une valeur limite supérieure, et la deuxième lorsque l'armage du ressort est plus faible qu'une valeur limite inférieure, les première et deuxième parties tournant conjointement tant que l'armage du ressort est compris entre ses valeurs extrêmes.

More specifically, the invention relates to a power reserve indicator mechanism for a timepiece movement of the type comprising a frame, a power source formed of a barrel and a mainspring housed in the barrel. , a work train driven by the barrel and winding means of the mainspring. This mechanism includes:

• a power reserve indicator with a mobile and a display device carried by the mobile,
• a differential gear kinematically connected by a first input to the barrel, a second input to the winding means and an output to the indicator, and
• an intermediate mobile having first and second parts respectively kinematically connected to the output and the mobile of the indicator and a connecting member connecting these parts, arranged so that the indicator occupies a position between two extreme positions, the first hit when spring arming is stronger an upper limit value, and the second when the winding of the spring is lower than a lower limit value, the first and second parts rotating together as the winding of the spring is between its extreme values.

According to the invention, the connecting member comprises a friction mechanism arranged so that the first part can move frictionally with reference to the second when the indicator has reached its first extreme position, and an elastic element arranged so that it can be armed when the indicator has reached its second extreme position, by moving the first part with reference to the second part.

• lorsque l'indicateur occupe sa première position extrême et que l'armage du ressort-moteur se poursuit, le levier est maintenu contre la butée et tourne à friction sur la partie dont il est solidaire, de telle sorte que l'indicateur reste immobile, et
• dès que le ressort-moteur se désarme, l'indicateur quitte sa première position extrême, les première et deuxième parties du mobile intermédiaire tournant ensemble.

Advantageously, the friction mechanism comprises an abutment integral with one of the parts and a lever frictionally mounted on the other part, arranged and dimensioned so that:

• when the indicator occupies its first extreme position and the winding of the mainspring continues, the lever is held against the stop and rotates with friction on the part of which it is secured, so that the indicator remains stationary, and
• as soon as the mainspring disarms, the indicator leaves its first extreme position, the first and second parts of the intermediate mobile rotating together.

The lever is provided with a longitudinal slot widening into an opening engaged on the pinion.

The elastic element is integral with the part comprising the stop and cooperates with the lever so that, when the indicator occupies its second extreme position, it is immobilized, while the motor spring drives the finishing gear and the differential gear, and that the elastic element arrests and then disarms when winding the mainspring.

• l'élément élastique est formé d'une lame élastique fixée par une première de ses extrémités à la roue, tandis que sa deuxième extrémité, libre, est disposée de manière à ce qu'elle appuie le levier contre la première extrémité,
• le mobile intermédiaire comporte une roue formée d'une planche dont la périphérie est munie d'une denture, un pignon formé d'un manchon muni à l'une de ses extrémités d'une denture, une entretoise disposée sur le manchon, le levier étant clipsé sur le manchon pour maintenir ladite roue qui est montée libre en rotation sur l'entretoise, et
• le ressort-moteur est de type à bride glissante.

The mechanism further includes the following features:

• the elastic element is formed of an elastic blade fixed by a first of its ends to the wheel, while its second end, free, is arranged so that it supports the lever against the first end,
• the intermediate mobile comprises a wheel formed of a board whose periphery is provided with a toothing, a pinion formed of a sleeve provided at one of its ends with a toothing, a spacer disposed on the sleeve, the lever being clipped on the sleeve to maintain said wheel which is free to rotate on the spacer, and
• the mainspring is of sliding flange type.

• la figure 1 est une vue en coupe d'un mécanisme indicateur de réserve de marche selon l'invention,
• les figures 2 et 3 sont des vues de dessus et en coupe du mobile intermédiaire, et
• la figure 4 est un diagramme montrant la variation du couple en fonction de l'angle d'armage du ressort-moteur.

Other advantages of the description will appear more clearly on reading the description which follows, made with reference to the appended drawing in which:

• the figure 1 is a sectional view of a power reserve indicator mechanism according to the invention,
• the Figures 2 and 3 are views from above and in section of the intermediate mobile, and
• the figure 4 is a diagram showing the variation of the torque as a function of the winding angle of the mainspring.

The mechanism according to the invention is intended to take place in a watch movement. It is mounted on a plate 8 partially visible in the drawing. The movement comprises a power source formed of a barrel 10, rotatable about a shaft 12 pivoting on the plate 8 and in which is housed a motor spring 14 provided with a sliding flange, not explicitly shown in FIG. drawing. The shaft 12 carries a ratchet wheel 16 which, driven in rotation by means of a not shown winding crown, makes it possible to arm the mainspring 14.

The barrel 10 drives the finishing gear which is not shown in the drawing either.

The mechanism further comprises a differential 18 described in detail in the aforementioned EP application. In summary, it comprises a shaft 20 placed at its output, a planet carrier 22 integral in rotation with the shaft 20 and carrying a satellite 24 with conical teeth. A first and a second input respectively consist of a first 26 and a second 28 wheels mounted freely on the planet carrier 22.

The wheels 26 and 28 are each formed by a board identified by the letter a and whose periphery bears a toothing b, and a pinion c provided with a conical toothing d. The wheel 26 meshes, by its toothing 26b, with the barrel 10. The wheel 28 meshes, by its toothing 28b, with a return 30, meshing itself with the ratchet wheel 16. Finally, the teeth 26d of the pinion 26c and 28d of pinion 28c are engaged with the satellite 24.

The gear ratios between the barrel 10 and the first input wheel 26, on the one hand, and the ratchet wheel 16 and the second input wheel 28, on the other hand, are equal, so that that for the same angle traveled by the barrel 10 and the ratchet wheel 16, the wheels 26 and 28 travel at equal angles.

In addition, the mechanism comprises an intermediate mobile 32, particularly illustrated on the Figures 2 and 3 , It is pivotally mounted on the plate 8. It comprises a pinion 34 formed of a sleeve 34a provided at one of its ends with a toothing 34b. The sleeve 34a is formed of a cylindrical portion 34c and a conical portion 34d widening of the portion 34c outwardly.

The mobile 32 further comprises a wheel 36 formed of a board 36a whose periphery is provided with a toothing 36b which meshes with the shaft 20 of the differential 18. A spacer 37 is driven on the portion 34c of the sleeve 34a. The wheel 36 is mounted free to rotate on the spacer 37 and can thus rotate on the pinion 34.

Particularly to the invention, a lever 38 of rectangular shape and whose length is about 0.75 times that of the diameter of the wheel 36, is provided with a longitudinal slot 41 widening into an opening 42 located approximately two-thirds of its length. The lever 38 thus has, on both sides of the opening 42, a large arm 38a and a small arm 38b. It is clipped on the tapered portion 34d of the pinion 34 so as to ensure the axial retention of the wheel 36. The pinion 34 and the lever 38 thus form a friction mechanism whose limiting torque is defined by the elasticity of the arms 38a. and 38b.

Furthermore, a spring 40 formed of an elastic blade in a circular arc embracing an angle of about 270 ° is fixed, by one of its ends 44 and in known manner, to the board of the wheel 36. Its other end 46, free, forms a bend 46a folded towards the outside of the wheel and arranged so that, at rest, it is in abutment against the large arm 38a, near the opening 42 and thus maintains the lever resting against the end 44 of the blade.

Finally, figure 1 also shows that the mechanism comprises a mobile indicator 48 pivotally mounted on a rod 50 driven into the plate 8. It comprises a board 48a provided, at its periphery, a toothing 48b in engagement with the pinion 34, and a gun 48c s extending beyond the plate 8 and intended to carry a power reserve indicator needle, not shown in the drawing.

The board 48a has a cutout 48d shaped annular sector embracing an angle of about 150 ° corresponding to the angle of movement of the needle. A pin 52, driven into the plate 8 is engaged in the cut 48d and serves as a stop to the mobile 48, a first and a second extreme positions are defined.

In a watch movement provided with the mechanism that has just been described, the motor spring 14, disarming, rotates and in a conventional manner the barrel 10 which meshes with the work train.

The aforementioned EP application describes in detail the operation of the differential 18 during the winding and disarming of the mainspring 14. It will therefore not be repeated here.

In normal operation, that is to say when the mainspring is sufficiently armed to properly drive the finishing gear of the movement and that the mobile indicator is between its two extreme positions, then the spring 40 causes, by its end 44, the lever 38, which is clamped between the ends 44 and 46a of the spring 40.

The mainspring 14 disarms slowly by driving the finishing gear train. As can be seen on the figure 4 , the torque of the motor spring 14, represented by the curve 58a, decreases until a limit value 60a is reached.

The power reserve indicator then indicates that it is exhausted and the mobile indicator is immobilized, the end of the cutout 48d being in abutment against the pin 52.

Like the mechanism described in the document EP already cited, if the user of the watch still does not raise the mainspring 14, it continues disarming by operating the movement of the watch. The differential 18 continues to rotate and, with it, the wheel 36. As the pinion 34 meshes with the mobile indicator 48, it is blocked. The wheel 36 thus has a relative movement with respect to the pinion 34. This movement is made possible because the wheel 36 is connected to the pinion 34 by the spring 40 which is armed. As shown in the curve 62a, the torque generated by the spring 40 increases from point 64 to point 65 where the couples of the mainspring 14 and the spring 40 compensate, so that the watch stops.

Then, the user proceeds to arm the motor spring 14 illustrated by the curve 58b. The spring 40 disarms (curve 62b) then, when the lever 38 returns to its rest position, the torque of the mainspring reaches a certain value at point 60b, the mobile indicator is again driven and the indicator moves with respect of the scale of the dial. During this winding operation of the mainspring, the end 44 of the spring 40 drives the lever 38 with a torque that is lower than the friction torque of the lever on the pinion, and thus carries with it the pinion 34. Then, when the power reserve indicator displays the maximum load, the indicator mobile is immobilized. The torque of the corresponding motor spring 14 is shown at point 66 of the curve 58b. The pinion 34 is then blocked since it meshes with the mobile indicator.

If the user of the watch continues to arm the mainspring 14, he must then overcome the friction of the lever 38 on the sleeve 34a, which is illustrated by the portion 68 of the curve 58b. The lever 38, abutting on the end 44 of the spring 40, thus pivots on the pinion 34 to the maximum winding of the mainspring 14. Thanks to the sliding flange system, the torque of the latter is stabilized at the level of the plate 70, despite the continuation of the arming. This gives a perfect fit of the various elements of the mechanism of the indicator and a correspondence between the extreme positions of the lever and the indicator and the maximum armature of the mainspring, without having to take any particular action when setting up place constituents of this mechanism.

The next disarming cycle proceeds as described above. Then, during the next reset, thanks to the setting made during the first cycle, the user knows that when the indicator reaches its extreme position, the mainspring is fully armed.

In the device as described, the introduction of the various components does not require any particular measure, both in terms of production and after-sales service, the indicator automatically stalling in its correct position, thanks to the fact that, during arming, the lever 38 rotates frictionally on the pinion 34, while, during disarming, the setting is maintained, because the spring 40 is armed. It is obvious that to allow these provisions, the armature torque of the spring 40 must always remain lower than the friction torque of the lever 38 on the conical portion 34d.

Claims (7)

1. Power reserve indicator mechanism for a timepiece of the type comprising a frame, an energy source formed of a barrel (10) and a mainspring (14) housed in the barrel, a going train driven by said barrel and means for winding said mainspring (14), and including:

   - a power reserve indicator with a wheel set (48) and a display device carried by the wheel set,

   - a differential gear (18) kinematically coupled by a first input (26) to the barrel (10), by a second input (28) to the winding means and by an output (20) to said indicator, and

   - an intermediate wheel set (32) including first and second parts respectively kinematically coupled to said output (20) and to the wheel set (48) of said indicator and a coupling member coupling said parts, arranged such that said indicator occupies a position comprised between two end positions, the first reached when the winding of the mainspring (14) is greater than an upper threshold value, and the second when the winding of the mainspring (14) is less than a lower threshold value, said first and second parts rotating conjointly while the winding of the mainspring (14) is comprised between its extreme values,
   characterized in that said coupling member includes a friction mechanism arranged such that the first part can move with friction in relation to the second part when the indicator has reached its first end position, and an elastic element (40) arranged so as to be able to be cocked when the indicator has reached its second end position, by the movement of the first part with reference to the second part.
2. Mechanism according to claim 1, characterized in that said friction mechanism includes a stop (44) secured to one of said parts and a lever (38) friction mounted on the other part, disposed and sized such that:

   - when the indicator occupies its first end position and the mainspring (14) continues to be wound, said lever (38) is held against said stop and rotates with friction on the part to which it is secured, such that the indicator remains immobile, and

   - as soon as the mainspring (14) is let down, the indicator leaves its first end position, the first and second parts of the intermediate wheel set (32) rotate together.
3. Mechanism according to claim 2, characterized in that said lever (38) is provided with a longitudinal slot (41) that enlarges into an opening (42) engaged on the pinion (34).
4. Mechanism according to one of claims 2 and 3, characterized in that said elastic element (40) is secured to the part including said stop (44) and cooperates with said lever (38) such that, when said indicator occupies its second end position, it is immobilized, whereas the mainspring (14) drives the going train and said differential gear, and in that said elastic element (40) is cocked, then let down when the mainspring is being wound.
5. Mechanism according to claim 4, characterized in that said elastic element (40) is formed of an elastic strip fixed via one of its ends to said wheel (36), whereas its other, free, end (46) is disposed such that it holds the lever against said first end.
6. Mechanism according to any of claims 1 to 5, characterized in that said intermediate wheel set (32) includes a wheel (36) formed of a plate (36a) whose periphery is provided with a toothing (36b), a pinion (34) formed of a sleeve (34a) provided at one of its ends with a toothing (34b), a spacer (37), disposed on the sleeve (34a), said lever being securely mounted on the sleeve (34a) to keep said wheel (36) free in rotation on the spacer (37), and in that the part coupled to the output (20) is the wheel (36).
7. Mechanism according to any of claims 1 to 6, characterized in that said mainspring (14) is of the slipping spring type.

Images