EP0851320B1 - Timepiece driven by mechanical means and with reserve power indicating system - Google Patents

Description

The present invention relates to a timepiece having a mechanism driven by mechanical means and a power reserve indication device for this mechanism according to the preamble of claim 1.

For a very long time, mechanical movements watchmakers were fitted with indication devices power reserve. These reserve indication devices of running indicate the level of winding of the motor spring, also called barrel spring or by simplification barrel. The level of winding of the barrel spring corresponds to the state of tension of this spring and corresponds so at a certain power reserve of the mechanism driven by the barrel (FR-A-405 768).

The known power reserve devices are all relatively complex and in particular require the addition bulky items. A classic power reserve is formed by a set of wheels used to reduce the rotating barrel path so that an indicator driven by this assembly undergoes a lower rotation 360 ° between the maximum cocking position and the position minimum winding spring. Such a gear therefore normally requires several wheels which increase the obstruction of the movement and complicates the construction of it. Therefore, the arrangement of a reserve of classic step in a mechanical watch movement is relatively expensive and the congestion resulting from such device leads to construction difficulties does that cannot always be resolved, especially in the framework of movements of reduced dimensions, for example for ladies' wristwatches.

The object of the present invention is to overcome the disadvantages of the prior art by proposing a part timepiece equipped with a power reserve device which can be bulky and easily integrated into any mechanical watch movement. In addition, the invention has for the purpose of providing a power reserve device inexpensive and easy to build.

To this end, the present invention relates to a timepiece including a barrel, used for mechanical energy storage for training a mechanism, and a device for indicating the reserve of step of this mechanism, characterized in that the power reserve indication device is formed by an elastic element, mechanically coupling in rotation first and second mobiles driven by the barrel in rotation around a common geometric axis, and by first and second display means integral with rotation of said first and second respectively movable and arranged to indicate an offset angular between two directions defined respectively by these first and second display means at least within a range of determined values of this offset angular.

Thanks to the features of the invention, a indication of the level of arming of the barrel, i.e. barrel spring tension level, or the moment of force exerted by the barrel on the gear train of the mechanism is directly displayed so that a user can know the power reserve of the piece of watchmaking. In an embodiment which will be described below, it will be noted that the reserve indication of walking requires a very limited number of elements additional and in particular no additional wheel.

At each level of barrel spring winding corresponds to a moment of unequivocal force exerted by the barrel on the gear train driven by this barrel. Thus, the indication of the moment of force exerted by the barrel on the driven mechanism, in particular on the gear train, gives an indication perfectly defined and unequivocal of the level of armament of the barrel spring.

In a particular embodiment, it is provided means to limit the angular offset between the first and second display means so as to limit above and / or below the time of force exerted on the elastic element of the power reserve according to the invention.

• la figure 1 est une vue en coupe d'un premier mode de réalisation d'un dispositif de réserve de marche selon l'invention;
• les figures 2a, 2b et 2c sont des vues de dessus partielles au niveau de la ligne de coupe II-II de la figure 1 qui représentent respectivement trois positions différentes correspondants à des niveaux d'armage différents du ressort de barillet équipant le mouvement horloger mécanique représenté à la figure 1;
• la figure 3 représente graphiquement le moment de force exercé par le barillet sur le pignon en prise directe avec celui-ci en fonction du niveau d'armage du ressort de barillet;
• la figure 4 est une vue partielle de dessus du premier mode de réalisation où les moyens d'affichage du dispositif de réserve de marche sont représentés;
• la figure 5 est une vue en coupe d'un deuxième mode de réalisation d'un dispositif de réserve de marche selon l'invention;
• la figure 6 est une vue éclatée de côté d'un ressort couplant mécaniquement en rotation deux mobiles selon le deuxième mode de réalisation de l'invention;
• les figures 7 et 8 sont respectivement deux vues en plan des deux mobiles représentés à la figure 6 selon les directions de projection VII et VIII de cette figure 6;
• la figure 9 est une vue de dessus du deuxième mode de réalisation selon la figure 5 où seuls les moyens d'affichage du dispositif d'indication de réserve de marche ont été représentés;
• la figure 10 est une variante de réalisation des moyens d'affichage.

Particular characteristics and other advantages of the present invention will be described below, with the aid of the following description made with reference to the appended drawings, given by way of non-limiting examples, in which:

• Figure 1 is a sectional view of a first embodiment of a power reserve device according to the invention;
• Figures 2a, 2b and 2c are partial top views at the cutting line II-II of Figure 1 which respectively represent three different positions corresponding to different levels of winding of the barrel spring fitted to the mechanical watch movement shown in Figure 1;
• FIG. 3 graphically represents the moment of force exerted by the barrel on the pinion in direct engagement with the latter as a function of the level of winding of the barrel spring;
• Figure 4 is a partial top view of the first embodiment where the display means of the power reserve device are shown;
• Figure 5 is a sectional view of a second embodiment of a power reserve device according to the invention;
• Figure 6 is an exploded side view of a spring mechanically coupling in rotation two mobiles according to the second embodiment of the invention;
• Figures 7 and 8 are respectively two plan views of the two mobiles shown in Figure 6 along the directions of projection VII and VIII of this Figure 6;
• Figure 9 is a top view of the second embodiment according to Figure 5 where only the display means of the power reserve indication device have been shown;
• Figure 10 is an alternative embodiment of the display means.

With the aid of Figures 1 to 4, a description will be given below. first embodiment of a timepiece mechanical with reserve indication device step according to the invention.

The power reserve device includes a first mobile 2 and a second mobile 4 coupled mechanically rotated by a helical spring 6 which provides elastic coupling between mobiles 2 and 4. The two mobiles 2 and 4 are arranged coaxially to be rotated by the barrel 8 around a common geometric axis 10. The mobile 2 is formed by an axis central 12 and a pinion 14 whose toothing 16 is in direct engagement with the toothing 18 of the barrel 8. The mobile 4 is formed by a cylindrical part 20 and a wheel toothed 22. The wheel 22 meshes with the pinion 24 of a mobile 26.

The cylindrical part 20 of the mobile 4 is mounted on axis 12 of mobile 2 so that it can rotate around of the geometric axis 10 independently of the rotation of the mobile 2. However, according to the invention, the mobile 2 is elastically coupled in rotation to mobile 4 by means of spring 6. To do this, the first end 28 of spring 6 is fixed to mobile 2 while the second end 30 of this spring 6 is fixed to the mobile 4. The fixing of the spring 6 to the mobile 2 and 4 can be made in various ways within the reach of man trade and in particular, as shown, by the introduction ends 28 and 30 in provided holes in mobiles 2 and 4 respectively. The spring 6 being housed between wheel 22 and pinion 14, it is not necessary that the ends 28 and 30 are introduced by force in the corresponding holes since the spring 6 is positioned axially by the pinion 14 and the base 32 supporting the wheel 22.

Axis 12 has a pivot at one end 34 mounted in a bearing 36 in a conventional manner. On the side of the plate 38, the axis 12 and the cylindrical part 20 which surrounds it through plate 38 to allow the arrangement of a disc or plate 40 integral with the mobile 4 and a needle 42 secured to the mobile 2, the needle 42 being located above the disc 40 which is arranged in an opening of the dial 44. The hands 45 used to the time display are arranged to rotate above needle 42.

The disc 40 and the needle 42 shown from above at FIG. 4 serve as means of displaying the reserve of market. At least 40 mark is shown on the disc 40 46 used to define an angular offset α between the direction defined by this reference 46 and the geometric axis of rotation 10 and the direction of the longitudinal axis 48 of needle 42. The angular offset α gives a indication of the power reserve of the driven mechanism by barrel 8, as will be described in more detail below using Figures 2 and 3.

In order to limit the angular offset α inside of a determined range of values, it is expected that the part of the cylinder 20 located near the pinion 14 or open laterally so as to define a first surface 50 and a second surface 52 forming stops for a pin 54 projecting from the pinion 14 in the direction of the mobile 4. Thus, the angular offset is limited lower by the stop 50 and higher by the stop 52.

As shown in Figure 3, the limitation of the angular offset α corresponds to a limitation of the moment of force exerted by the barrel 8 on the spring 6. Curve 56, which represents the moment of force M as a function of the angular offset β defined by the angle at the center of the two ends 28 and 30 of the spring 6, is increasing monotonous. When the pin 54 is in support against the stop 50, as shown in the Figure 2a, the angle β has the value 2a which corresponds to a minimum moment of force M1 exerted by the barrel on the spring 6.

When the moment of force exerted by the barrel on the spring 6 is greater than the value M1, the angle β increases substantially linearly. On the face 2b is shown the relative position of the pin 54 relative to the sectioned cylinder 20 corresponding to a moment of force M2 greater than M1 and the value 2b for the angle β. Since curve 56 is monotonous increasing, we will note that with each given value of the moment of force M corresponds to a single determined value of the angle β.

Finally, when the moment of force exerted on the spring is equal M3, the pin 54 comes to bear against the stop 52, this value M3 thus defining a value maximum for the moment of force exerted on the spring. The angle β can therefore vary between the value 2a and the value 2c. The pin 54 being integral in rotation with the mobile 2 and the end 30 of the spring 6 being integral in rotation of the mobile 4, the angular offset α between the reference 46 and the axis 48 of the needle 42 is equal to the angle β decreased or increased by a predetermined constant value.

The angular offset α is limited below by the pin 54 and the surface 50 of the cylinder 20. Similarly, the angular offset α is limited superiorly by means of the pin 54 and of the surface 52 of the cylinder 20. The minimum value of the offset α corresponds to β = 2a while the maximum value of the angular offset α corresponds to β = 2c. Thus, the offset α gives an indication of the power reserve of the timepiece mechanism according to the invention since it gives an indication the moment of force exerted by the barrel on the mobile 2, this moment of force having a value dependent on the level reinforcement, i.e. the tension of the spring of the barrel serving as a mechanical energy accumulator.

Note that mobiles 2 and 4 are part of the train conventional gear of the driven watch mechanism by barrel 8. As a result, the indication device power reserve can easily be integrated into the various existing mechanical watch movements. The dimensions resulting from the device for indicating power reserve according to the invention is almost zero at level of watch movement, only display means of the power reserve provided at the dial cause some congestion since the disc 40 and needle 42 are both driven in rotation.

In order to limit the increase in height of the timepiece, it was planned to arrange the disc 40 in an opening of the dial 44. Therefore, the present invention does not increase the height of the timepiece relative to power reserves conventional. It will be noted here that the means of lower and upper limitation of angular offset α are advantageous and form a preferred variant of realization, but are not necessary for the indication of the power reserve according to the invention. However, these means for limiting the angular offset α form a improvement of the invention making it possible to spare the spring 6 by limiting the moment of force exerted on it and also to ensure a certain linearity between the level tension of the barrel spring and the angular offset α within the predetermined accessible range of values.

In an alternative embodiment, the spring 6 is a spring developing in a spiral. Such a spring presents the advantage of being flat and therefore of height reduced, which can be an advantage for movements low mechanical height. In the case of a spring in spiral, the cross section of the spring can be either circular, or rectangular when the spring is formed by a metallic ribbon wound on itself at the way of a barrel spring.

It will also be noted that the reserve device walking can be arranged on mobiles intervening downstream in the gear train driven by the barrel 8 relative thereto. So the pinion 14 is not necessarily in direct contact with the teeth 18 of the barrel 8. As an example, the reserve device step according to the invention can be arranged at the mobile 26, which should be transformed according to the invention into two coaxial mobiles similar to mobiles 2 and 4 of the first embodiment described using the Figures 1 to 4.

It will also be noted that the lateral opening made in the cylinder 20 is preferably less than 180 °, which limits the variation of the angular offset α to one value less than 180 °. In this case, the angle at the center defined by the surface 50 and the direction given by the end 30 of the spring 6 and the geometric axis 10, in a plane perpendicular to this geometric axis 10, is advantageously between -70 ° and + 70 °, the surface 50 defining the minimum winding position of spring 6. From this fact, the holding in place of the mobile 4 is guaranteed. AT as an example, the angle at the center defined by the surfaces 50 and 52 is between 120 ° and 150 °.

However, given the forces involved acting on the cylinder 20, the lateral opening can be greater than 180 ° provided that the end 30 of the spring 6 is judiciously fixed to the mobile 4 so to ensure that the reaction force exerted by the axis 12 on cylinder 20 is oriented towards the solid part of the cylinder open laterally.

With the aid of FIGS. 5 to 9, there will be described below a second embodiment of a timepiece according to the invention. The elements already described in the first embodiment will not be again described here in detail.

The power reserve device again includes mobiles 60 and 62 arranged to undergo a rotation around a geometric axis 10 common to the two mobiles 60 and 62. The mobile 60 engages with the barrel 8 and is rotatably coupled to the mobile 62 using a spring helical 6. The mobile 60 differs from the mobile 2 in that the part projecting from the pinion 14 towards of the mobile 62 is formed by a projection 64 in the form of annular section defining at its two ends two flat surfaces 66 and 68. The mobile 62 differs from the mobile 4 in that it is formed by a cylinder 70 not having side opening and not crossing the plate 38 as in the first embodiment. In addition, the mobile 62 has a section-shaped projection 72 annular which extends in the direction of the mobile 60 so equivalent to the projection 64. The projection 72 defines also at its two ends two flat surfaces 74 and 76. The internal radius R defined by the projections 64 and 72 is greater than the radius defined by spring 6 relative to the geometric axis 10.

The spring 6 is arranged around the part cylindrical 70 of the mobile 62. The mobile 60 and 62 are mounted coaxially so that the surface 74 can come to bear against the surface 66 and that the surface 76 can come to bear against surface 68 of so as to limit lower and higher the angular offset α in the display of the power reserve as shown in Figure 9. The arrangement of projections 64 and 72 is such that the moment of force exerted on the spring 6 varies substantially between a value M1 and a value M3 as shown in the Figure 3 in the context of the description of the first mode of achievement.

The ends 28 and 30 of the spring 6 are bent radially and not axially as in the first mode of achievement. In addition, the end 28 is arranged to so as to be in abutment against the surface 68 of the projection 64 and the end 30 is arranged so as to be in bearing against the surface 76 of the projection 72. In order to avoid the end 30 does not come between the surface 68 and surface 76 when these two surfaces approach one from the other, the end 30 is located axially at a higher level relative to the upper surface 78 of the projection 64. It will be noted that, in FIGS. 6 and 8, the teeth 16 of the pinion 14 have not been drawn explicitly but was only represented by a circle interrupted.

Then there is provision in this second mode of realization that the tray or disk 40 means display is arranged on a wheel 80 integral with rotation of the wheel 22 of the mobile 62, the wheel 80 being rotatably coupled to wheel 22 via a pinion 82 having a first lower toothing 84 which meshes with the wheel 22 and a second toothing upper 86 which meshes with the wheel 80. The pinion 82 to double toothing serves as a rotation multiplier of such so that the angular offset α between the axis longitudinal 48 of needle 42 and mark 46 provided at the surface of the disc 40 can vary between two values limits, namely a minimum value and a value maximum, the difference of which is greater than the distance relative possible for the mobile 62 relative to the mobile 60. In other words, the maximum center angle between the surface 68 of projection 64 and surface 76 of projection 72 is less than the angular difference between the maximum value and minimum value of the offset angular α displayed by the display means 40 and 42 shown in Figure 9.

The pinion 82 is masked by means of the dial 44 and the disc 40. Note that the presence of the wheel 80 physically separated from disk 40 is not mandatory. In fact, in a variant, the plate 40 itself comprises at its circumference a toothing meshing with the upper teeth 86 of the pinion 82. We will also notice that the spring 6 is perfectly housed between the mobiles 60 and 62. In addition, its angular positioning is ensured by the fact that the ends 28 and 30 of this spring 6 are constantly pressing against the respective surfaces 68 and 76 against which they are arranged given that the spring 6 is constantly subjected to a moment of force not zero.

Regarding the means of displaying the offset angular α representative of the tension level of the spring barrel and therefore of the power reserve, it will be noted that several realizations are possible and conceivable by the skilled person. A variant has been shown in the Figure 10. In this Figure 10, there is provided a needle 42 and an element 88 having the shape of an anchor or of a T with a circular crossbar 90. On the bar 90 is provided a scale defining at least one item 46 used to define an angular offset with needle 42. Ultimately, it is possible to predict only two needles defining two directions angularly offset by an angle varying according to the moment of force exerted on the spring 6. The arrangement of these two needles can be provided so that when these two needles are superimposed, the user of the timepiece according to the invention is informed of the fact that the moment of force exerted by the barrel 8 has become insufficient for the proper functioning of the mechanism it drives.

We can also provide two discs, the disc upper has an opening or clearance at its periphery allowing a user to know by example if the power reserve is low or if the moment force exerted by the barrel on the gear train has become too weak for the proper functioning of the mechanism driven by this barrel. We can also provide two trays with various shapes including the overlay defines an evolving pattern based on angular offset between these two plates.

It will also be noted that a person skilled in the art can foresee an arrangement in which the associated display means to the two mobiles elastically connected by the spring 6 are located substantially in one and the same plane. A such a variant, although of less easy construction, reduces the height required for the means display indicating the power reserve or the level of barrel spring tension.

Claims (10)

1. Timepiece including a barrel (8), used for storing the mechanical energy for driving a mechanism, and a device for indicating the power reserve of said mechanism, characterized in that said power reserve indicating device comprises a resilient element (6) rotatively coupling in a mechanical manner first and second wheels (2, 4; 60, 62) rotatively driven by said barrel about a common geometric axis (10), and first and second display means (40, 42) rotatively coupled to said first and second wheels respectively and arranged so as to indicate an angular displacement between two directions (46, 48) determined respectively by said first and second display means, at least within a determined range of values of said angular displacement.
2. Timepiece according to claim 1, characterized in that said resilient element (6) is formed of a helical spring (6).
3. Timepiece according to claim 1, characterized in that said resilient element (6) is formed of a spiral coiled spring (6).
4. Timepiece according to any of claims 1 to 3, characterized in that said first and second wheels (2, 4; 60, 62) are first and second toothed wheels of a gear train of said mechanism.
5. Timepiece according to claim 4, characterized in that said first toothed wheel (2; 60) is a pinion directly engagiAg with said barrel.
6. Timepiece according to any of the preceding claims, characterized in that one of said first and second display means (40, 42) is formed of a disk (40) having on its surface at least a reference mark (46) and the other of said first and second display means is formed of a hand (42) defining an axis (48) indicating said angular displacement (α) with respect to said reference mark.
7. Timepiece according to any of the preceding claims, characterized in that said power reserve indicating device includes first means (54, 20, 52; 64, 72, 68, 76) for limiting said angular displacement (α) so as to provide an upper limit to the moment of force exerted on said resilient element (6) by said barrel (8).
8. Timepiece according to any of the preceding claims, characterized in that said power reserve indicating device includes second means (54, 20, 50; 64, 72, 66, 74) for limiting said angular displacement (α) so as to provide a lower limit for the moment of force exerted on said resilient element (6) by said barrel (8).
9. Timepiece according to claim 7, characterized in that said first angular displacement limiting means comprise a projecting part (54;64) fixed to one of said first and second wheels (2, 4; 60, 62) and a stop (52; 76) fixed to the other of said first and second wheels and arranged so that said projecting part abuts against said stop when said moment of force reaches a given maximum value.
10. Timepiece according to claim 8, characterized in that said second means comprise a projecting part (54; 64) fixed to one of said first and second wheels (2, 4; 60, 62) and a stop (52; 76) fixed to the other of said first and second wheels and arranged so that said projecting part abuts against said stop when said moment of force reaches a given minimum value.

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