WO2011058157A1 - Timepiece movement - Google Patents

Abstract

The invention relates to a timepiece movement comprising an energy source (12), a time base provided with a plurality of balances (16) pivoting about the respective axis of rotation thereof, means (14) for connecting the energy source (12) to the time base, and mobiles arranged to carry time display means (18). According to the invention, said balances (16) are oriented such that planes perpendicular to axes of rotation thereof define a regular polyhedron.

Description

 Description

 Movement for timepiece

Technical area

 The present invention relates to movements for a timepiece of the type comprising a power source, a time base provided with several rockers, means for connecting the energy source to the time base, and mobiles arranged to carry time display means.

 State of the art

[0002] The fact of providing the movement of several rockers improves the accuracy of the watch. Some parts, for example that described in patent CH 156801 comprise two rockers arranged in the same plane. Such a solution makes it possible to reduce the differences in operation between the different positions of the watch, however modestly. Another solution is to provide the watch with a tourbillon. To further reduce sensitivity to positions, some watches are equipped with two vortices whose axes of the pendulums are not parallel. A solution of this type is described in the patent application WO 2005/043257. The movements equipping such watches are of a great complexity. Moreover, the volume occupied by the vortex cages, as well as the energy consumed are important. Patent application WO 2008/101802 describes, in a variant, a watch provided with two inclined pendulums. Such a solution allows only partial compensation, the average inclination of the rockers relative to a reference plane can only be variable depending on the position of the watch in space.

 An object of the present invention is to provide a movement for a timepiece whose sensitivity to position changes is particularly low.

Disclosure of the invention

For this purpose, the present invention relates to a movement for a timepiece comprising a source of energy, a time base, means for connecting the energy source to the time base, and mobiles arranged to carry the time display means. According to the invention, said time base is formed of several rockers pivoting about their respective pivot axis, and oriented so that planes perpendicular to their pivot axes define a regular polyhedron.

 In this way, whatever the position of the watch movement, the average position of the axes of the rockers is constant. The regular polyhedron allows to have a complete compensation of the positions of the movement.

 The regular polyhedron is defined by one or more planes parallel to each other and perpendicular to the balance axes.

 In a first variant, said time base comprises four rockers and said polyhedron is a regular tetrahedron. In this case, only four planes perpendicular to the balance axes are required to define the tetrahedron.

 In a second variant, said time base comprises three pendulums and said polyhedron is a cube. In this case, it takes three times two planes parallel to each other and two to two perpendicular to one of the balance axes to define the cube.

 In a first embodiment, the energy source comprises at least one barrel per pendulum. In addition, said barrel is connected to the balance by a gear train. This movement comprises, in addition, a differential type structure connecting each of the gear trains to said mobiles.

 In a second embodiment, the movement further comprises a differential type structure and the energy source comprises at least one cylinder kinematically connected to said mobiles and rockers by said differential type structure.

 [001 1] It is advantageous that the time display means rotate about an axis forming a non-right angle with the axes of rockers. In this way, the thickness of the movement can be maintained at a reasonable value.

Brief description of the drawings

The invention will be better understood on reading the description which follows, given by way of example and with reference to the drawings in which: - Figures 1 and 2 show schematically the general structure of the variants in which the movement is equipped respectively with four and three rockers;

 FIGS. 3 and 4 schematically show differential type systems equipping respectively the movements illustrated in FIGS. 1 and 2;

 FIG. 5 is an alternative embodiment of the differential system of FIG. 4; and

 - Figure 6 illustrates a gear capable of allowing a change of work plan of a gear train.

 Embodiments of the invention

 [0013] The clockwork movement 10 shown very schematically in FIG. 1 has a truncated pyramid shape which, in the absence of truncation, would comprise four equilateral triangular-shaped faces, thus constituting a regular tetrahedron. The movement 10 is provided with four sets A, B, C and D shown diagrammatically by two circles, respectively illustrating a cylinder 12 and a rocker 16, connected to each other by a line, illustrating a work train 14. each of these sets, including in particular the rockers 16, are respectively perpendicular to one of the faces of the tetrahedron.

 The movement 10 carries, in addition, on mobile such as a roadway and a gun wheel not shown in the drawing, time display means formed by needles 18 visible in Figure 1.

For the displayed time to correspond to the average of the times measured by the four rockers 16, the movement 10 is provided with a differential type structure 20 (see Figure 3) kinematically connected to each of the barrels 12. More precisely , with reference to FIG. 3, this structure 20 comprises two spherical differential gears 22 and 24, each comprising two wheels forming entries identified respectively by the letters a and b, a satellite c, and a tree d, the letters being preceded by the reference of the corresponding differential gear. The wheels a and b of the two spherical differentials 22 and 24 are each connected kinematically to one of the systems A, B, C and D. Each of the satellites c is connected to the corresponding shaft on which the wheels a and b also pivot. These meshes with the satellite c.

 A third spherical differential gear 26 also comprises two wheels forming inputs 26a and 26b, a satellite 26c and a shaft 26d. The wheels 26a and 26b are respectively connected to pinions e integral with the shafts of spherical differentials 22 and 24. Conventionally, the two inputs 26a and 26b of the differential 26 mesh with the planet 26c which rotates the shaft 26d. In this way, the rotational movement of the shaft 26d of the differential 26 corresponds to the sum of the rotational movements of the inputs a and b of the differentials 22 and 24, which are a function of the frequency of the rockers 16 of the four sets A, B , C and D. Thus, by conventionally connecting the shaft 26d of the differential 26 to a timer gear 27, it is possible to display the time corresponding to the average frequency of the rockers of each of the sets A, B, C and D. Since the rockers are in such plans as the relative orientation of each of the rockers with reference to others is identical, regardless of the pendulum considered, it follows that the walking is practically not influenced by the position of the movement.

[0017] The clockwork movement 30 shown very schematically in FIG. 2 has a truncated pyramid shape having two equilateral triangular bases and three trapezoidal sides which, in the absence of truncation, would form three isosceles right triangles. This pyramid forms a part of a cube whose three faces are formed of a square obtained by the addition of a second right triangle adjacent to the three right triangles. The movement 30 is provided with three sets E, F and G diagrammatically represented by two circles, respectively illustrating the barrel 12 and the rocker 16, and a line illustrating the finishing gear 14. The axes of the mobiles of each of these sets, including the rockers 16, are respectively perpendicular to one of the faces of the cube. The movement 30 carries, in addition, on mobile such as a roadway and a gun wheel not shown in the drawing, time display means formed by needles 18 visible in Figure 2.

 For the displayed time corresponds to the average of the times measured by the three rockers 16, the movement 30 is provided with a differential type structure 32 (see Figure 4) kinematically connected to each of the barrels 12. More precisely , with reference to FIG. 4, this structure 32 comprises two spherical differential gears 34 and 36. The differential gear 34 comprises two wheels forming inputs 34a, 34b, a satellite 34c and a shaft 34d. The wheels 34a and 34b are respectively kinematically connected to the barrels 12 of the sets E and F. The satellite 34c is connected to the shaft 34d on which the two wheels 34a and 34b also pivot. The latter meshes with the satellite 34c.

A second spherical differential gear 36 also comprises two wheels forming inputs 36a and 36b, a satellite 36c and a shaft 36d. The input 36a of the differential gear 36 is kinematically connected to the shaft 34d of the differential gear 34 by means of a gear 34e integral with said shaft 34d, while the input 36b is kinematically connected to the barrel 12 of the gear 34. assembly G. The wheels 36a, 36b mesh with the satellite 36c, which rotates the shaft 36d of the differential gear 36. The movement of the shaft 36d of the differential 36 is therefore a combination of the movements applied to the inputs 34a and 34b of the differential 34 and the input 36a of the differential 36. In this case, however, the structure of the differential gears is not symmetrical. This is why it is necessary to adjust the gear ratios so that for each oscillation of the balance, the angle traveled by the display means is the same. In this way, the rotational movement of the shaft 36d of the differential 36 corresponds to the sum of the rotational movements of the inputs 34a and 34b of the differentials 34 and 36a of the differential 36, which are functions of the frequency of the rockers 16 of the three sets E, F and G. Thus, by conventionally connecting the shaft 36d of the differential 36, by a pinion 36e to a timer gear 37, it is possible to display the time corresponding to the average frequency of the rockers of each of the sets E, F and G. In this variant, it is noted that the three rockers are inclined relative to the plane of movement, and relative to the axis of the display means. Since the rockers do not form a right angle with the display means, the thickness of the movement can be kept within reasonable limits.

It is obvious that the differential gear 34 and 36 can also be arranged to be concentric, equipped with a single shaft 36d. Such a configuration is shown in Figure 5, the elements identical to the embodiment of Figure 4 are taken with the same references. The wheels 34a and 34b are respectively kinematically connected to the barrels 12 of the sets E and F, while the wheel 36b is connected to the barrel 12 of the assembly G. The satellite 34c is secured to a shaft 38 pivotally mounted on the shaft 36d, the shaft 38 is also integral in rotation with the wheel 36a. The wheels 36a and 36b meshing with the satellite 36c, which rotates the shaft 36d, the axis of the satellite 36c being fixed on the shaft 36d. In this way, the speed of rotation of the shaft 36d is a function of the rotational speeds of the barrels 12 of the three sets E, F and G, these speeds being defined by the frequencies of the rockers 12 of the same sets.

 As soon as the rockers oscillate in different planes, it is necessary to connect the inputs of the differentials to the barrels 12 by bevel gears, well known to those skilled in the art, such as that shown schematically in Figure 6.

 In both variants described above, each beam is powered by a barrel of its own. It is also possible to have only one barrel, and a tree structure, the barrel forming the trunk, while the differential structures 20 or 32 allow the existence of four, respectively three branches, each leading to the power supply. a pendulum.

With such watch movements, the effect due to changes in positions is greatly reduced. However, there may still be a residual effect due at the point of attachment of the spirals to the frame. To completely eliminate this defect it is possible to replace each of the rockers by a vortex, the axes of the cage and the balance being perpendicular to the faces of a regular polyhedron.

The regular polyhedra considered is a tetrahedron and a cube. It is obvious that the effect obtained could be the same with a polyhedron with more sides. The complexity of the mechanism and the volume occupied, however, would be significantly increased, for a modest improvement in accuracy.

Claims

claims 1. Movement for a timepiece comprising an energy source (12), a time base provided with several rockers (16) pivoting about their respective pivot axis, connecting means (14) of the source of energy energy (12) at the time base, and mobiles arranged to carry time display means (18), characterized in that said rockers (16) are oriented so that planes perpendicular to their axes of pivoting define a regular polyhedron.  2. Movement according to claim 1, characterized in that said time base comprises four rockers (16) and in that said polyhedron is a regular tetrahedron.  3. Movement according to claim 1, characterized in that said time base comprises three rockers (16) and in that said polyhedron is a cube. 4. Movement according to one of claims 1 to 3, characterized in that the energy source comprises at least one barrel (12) per balance (16), in that said barrel (12) is connected to the balance (16 ) by a gear train (14), and further comprising a differential-type structure (20, 32) connecting each of the gear trains (14) to said mobiles arranged to carry means for time display (18).  5. Movement according to one of claims 1 to 3, characterized in that it further comprises a differential type structure and in that the energy source comprises at least one cylinder kinematically connected to said mobiles and rockers by said differential type structure.  6. Movement according to one of claims 1 to 5, characterized in that the time display means (18) rotate about an axis forming non-right angles with the axes of the rockers (16).