CH716036A2 - Clockwork mechanism comprising a mechanical braking device for a mobile watchmaker. - Google Patents

Abstract

The invention relates to a timepiece mechanism comprising a braking device (100) by pressing, separate and remote from its guides, on a shaft (30) of a watch mobile, elastic blades (3) carried by a brake wheel ( 10) trapped between a structure (1) and a lock (6) and movable perpendicular to the axis of said shaft (30), where, - or all the supports on the shaft (30) of the blades (3) are exerted in a single angular sector with an angle at the center less than 180 °, - or opposite a first straight or convex blade tangentially braking said shaft (30), a second blade allows relative mobility between the braking unit (10) and said shaft (30) in a direction of mobility, the latter being: o either similar and substantially parallel to the first elastic blade, o or wavy hairpin elastic notch deformable perpendicular to said axis (D) and to the direction of mobility.

Description

Field of the invention

The invention relates to a clockwork mechanism comprising a supporting structure of at least a first device and / or a second device for guiding in pivoting a shaft of a moving body about an axis of rotation, and comprising at least one braking device which is separate and distant, in the direction of said axis of rotation, from any pivoting guide device that said mechanism comprises, said braking device comprising at least one braking mobile comprising at least one blade elastic designed to exert mechanical braking support on said shaft.

[0002] The invention also relates to a timepiece movement comprising at least one such timepiece mechanism.

[0003] The invention also relates to a watch comprising at least one such movement and / or at least one such clockwork mechanism.

[0004] The invention relates to the field of clockwork mechanisms, in particular display mechanisms.

Background of the invention

[0005] In an untensioned cog, the angular play of the display mobiles results in an unpleasant visual effect for the user, called jerking, as conventionally visible on a needle of a small seconds display with an untensioned cog.

[0006] Some systems already exist such as magnetic brakes, flexible teeth or springs serving as a brake. These are often chip springs (foils) or blades rubbing against the mobile, which have the drawback of inducing a large variation in friction force and therefore a variable disturbance of the rate.

[0007] Document EP3396470 in the name of ETA SA describes a clockwork mechanism comprising a structure in which a shaft of a mobile is pivoted, and comprising a braking device for mechanical braking at constant torque of this shaft, this device brake comprises a removable braking mobile relative to the structure and which comprises, for its attachment to the structure, a massive rim, which carries a plurality of elastic elements, distributed regularly around a common axis around which these elastic elements each comprise a contact zone, these contact zones together defining an opening arranged to cooperate by driving and resiliently clamping with the shaft, so as to make this common axis coincide with the axis of rotation of the shaft, and to apply at the shaft a substantially constant tangential braking force.

Summary of the invention

[0008] The invention proposes to reduce in a simple and economical manner the angular play of the display mobile device in an untensioned gear, and to make it easy to insert or radially extract a braking mobile.

[0009] To this end, the invention relates to a timepiece mechanism according to claim 1.

[0010] The invention also relates to a clockwork movement comprising at least one such clockwork mechanism.

[0011] The invention also relates to a watch comprising at least one such movement and / or at least one such clock mechanism.

Brief description of the drawings

Other characteristics and advantages of the invention will appear on reading the detailed description which follows, with reference to the accompanying drawings, where: FIG. 1 represents, schematically, and in plan view, part of a timepiece movement comprising a mechanism according to the invention, with a braking device which comprises a brake mobile of a shaft of a mobile, this braking mobile having relative mobility between a structure and a lock, both in the direction of the axis of the mobile to be braked and in a plane perpendicular to this direction; the brake mobile is shown in a first variant comprising elastic arms together forming a hairpin spring, a first blade being substantially straight and tangent to the mobile to be braked, and the other blade comprising two elastic notches on both sides another of the mobile to be braked, facilitating the radial insertion or extraction of the braking mobile relative to the mobile to be braked; FIG. 2 represents, in a manner similar to FIG. 1, a second variant of the braking mobile, comprising two straight blades on either side of the mobile to be braked, according to tangential supports that are substantially parallel to each other, the braking mobile comprising further anti-shock stops for limiting the relative radial travel between the braking mobile and the mobile to be braked; FIG. 3 represents the braking mobile of FIG. 2, alone; FIG. 4 represents, similarly to FIG. 1, another variant of the braking unit which comprises two blades each convex on the side of the shaft, on either side of the latter, which exert pressure on the shaft 'shaft in tangent directions parallel to each other, and which are arranged to allow the radial insertion of the braking mobile around the shaft; FIG. 5 represents, similarly to FIG. 1, another variant of the braking mobile which comprises a single blade with a bearing surface in a hollow cylindrical sector, which extends over an angular sector less than 180 ° with respect to the axis of the mobile to be braked; FIG. 6 represents, similarly to FIG. 5, another variant of the braking unit which comprises, in addition to the blade with a bearing in the hollow cylindrical sector of FIG. 5, another blade in support, all of the blades extending over an angular sector less than 180 ° relative to the axis of the mobile to be braked; FIG. 7 represents, schematically and in plan view, in superposition the two insertion and service positions, and shows the bringing into cooperation of a narrow part of the limitation lock through an opening of a fork that comprises the braking mobile; FIG. 8 represents, similarly to FIG. 1, yet another variant of the braking mobile, pivoted by a pin on the supporting structure and still limited in its movement by such a lock, and comprising two blades with a substantially spiral body and the ends of which are straight on either side of the mobile to be braked, according to tangential supports that are substantially parallel to each other; FIG. 9 schematically represents and in section passing through the axis of the mobile to be braked, the mechanism according to the invention in an embodiment with traditional pivots; FIG. 10 represents, schematically, and in section passing through the axis of the mobile to be braked, the mechanism according to the invention in an embodiment with flexible pivots, and in which the supporting structure can be integral with the mobile to be braked; FIGS. 11 to 14 represent, schematically, and in plan view, the stages of assembly of another variant of the braking mobile, this time single-blade, on a structure provided with a lock, and through from which a shaft pivots, which is also guided with guide means not shown, and which has to be braked: FIG. 11 shows the braking mobile in the free state, next to the structure; FIG. 12 shows the insertion of the shaft in a clearance of the braking mobile; FIG. 13 shows the support of the single elastic blade on the shaft, which bears diametrically on a top of a vee that the braking unit comprises facing the elastic blade; Figure 14 shows the service position reached after crossing this summit, the shaft bears on one side on the vee delimited by two vertices, and is braked on the opposite side by the single elastic blade, the forks of the braking unit grip the lock with a slight play; this lock can then be turned by a quarter of a turn, to limit the axial movement of the braking unit; FIG. 15 is a block diagram showing a watch comprising a movement with such a mechanism.

Detailed description of the preferred embodiments

The invention relates to a clockwork mechanism 1000, comprising a structure 1 carrying at least a first device 4 and / or a second device 5 for guiding in pivoting a shaft 30 of a mobile 40 around an axis of rotation D.

This mechanism 1000 comprises at least one braking device 100 which is separate and distant, in the direction of the axis of rotation D, from any pivoting guide device 4, 5, or other, that the mechanism 1000 comprises .

This braking device 100 comprises at least one braking mobile 10, which comprises at least one elastic blade 3, 31, 32, arranged to exert a mechanical braking support on the shaft 30.

According to the invention, this at least one braking mobile 10 extends substantially perpendicularly to the axis of rotation D, and is mounted prisoner between the structure 1 and a lock 6 that comprises the mechanism 1000, and is mobile at least in a plane perpendicular to the axis of rotation D, relative to the structure 1 and to the shaft 30.

And the arrangement of the blade 3, 31, 32, if it is unique as in Figure 5, or the relative arrangement of the different blades 3, 31, 32, when the braking mobile 10 has several as in the preferred variants illustrated by the other figures, is such that: or else all the supports on the shaft 30 of all the elastic blades 3, 31, 32, which the braking unit 10 comprises, are exerted in a single angular sector at an angle at the center α less than 180 ° with respect to the axis of rotation D, so as to allow relative mobility between the braking mobile 10 and the shaft 30 in a direction of mobility included in the angular sector; or else the braking mobile 10 comprises a first straight or convex elastic blade 31 arranged to tangentially brake the shaft 30 and whose direction defines a direction of mobility DM perpendicular to the axis of rotation D, and, on the side opposite to the first elastic blade 31 relative to the axis of rotation D, at least one second elastic blade 32 which is arranged to allow relative mobility between the braking mobile 10 and the shaft 30 in the direction of mobility DM, the second blade elastic 32 being: either single, and straight or convex, and arranged to tangentially brake the shaft 30 substantially parallel to the first elastic blade 31, that is to say in a direction parallel to the direction of tangency of the first elastic blade 31; or wavy in the manner of a hairpin and comprising at least one elastic notch 39 deformable in a direction perpendicular to the axis of rotation D and to the direction of mobility DM.

More particularly, the structure 1 is conventionally carrying a first device 4 and a second device 5 for guiding the pivoting shaft 30 about the axis of rotation D, distinct and distant from one another. the other, and these two guide devices are each separate and distant from the braking device 100.

More particularly, the structure 1 carries a first device 4 for guiding the pivoting shaft 30, which first guide device 4 comprises, or else a first bearing 40 of the structure 1 cooperating in a complementary manner with a first bearing 41 of the shaft 30, or else a first anchor 45 carrying a first flexible guide 46 from which the shaft 30 is suspended or to which the shaft 30 is integral.

[0020] More particularly, the structure 1 carries a second device 5 for guiding the pivoting shaft 30, which second guide device 5 comprises, or else a second bearing 50 of the structure 1 cooperating in a complementary manner with a second bearing 51 of the shaft 30, or a second anchor 55 carrying a second flexible guide 56 from which the shaft 30 is suspended or to which the shaft 30 is integral.

More particularly, the braking mobile 10 has axial mobility, with a first axial play, in the direction of the axis of rotation D, relative to the structure 1 and to the shaft 30.

[0022] More particularly, the braking mobile 10 is arranged to apply mechanical braking at constant torque on the shaft 30.

More particularly, the braking mobile 10 comprises at least one anti-shock stop 22, 23, which is arranged to limit the relative stroke between the braking mobile 10 and the shaft 30 in the direction of mobility DM. More particularly still, the braking mobile 10 comprises at least two anti-shock stops 22, 23, which are arranged on either side of the shaft 30, as can be seen in FIGS. 2 and 3.

More particularly, and as visible in Figures 2, 3, and 8, at least one brake mobile 10 comprises two parallel blades 31, 32, straight, on either side of the shaft 30, and which exert support on the shaft 30 in tangent directions parallel to each other, and which are arranged to allow the radial insertion of the braking mobile 10 around the shaft 30. More particularly, this brake mobile 10 comprises only these two parallel blades 31, 32.

More particularly, and as visible in Figure 4, at least one brake mobile 10 comprises two convex blades 31, 32, each convex on the side of the shaft 30, on either side of the shaft 30, and which exert support on the shaft 30 in mutually parallel tangent directions, and which are arranged to allow the radial insertion of the braking mobile 10 around the shaft 30. More particularly, this braking mobile 10 has only these two convex blades 31, 32.

In another variant not shown, at least one braking mobile 10 comprises a straight blade, which is opposite a convex blade, on either side of the shaft 30, and which exert support on the shaft 30 in tangent directions parallel to each other, and which are arranged to allow the radial insertion of the braking mobile 10 around the shaft 30. More particularly, this braking mobile 10 only comprises these two blades, one straight, the other convex.

More particularly, the braking mobile 10 comprises two elastic blades 31, 32, arranged on either side of the shaft 30 and together forming a hairpin spring comprising at least one elastic notch 39. More particularly, the first 31 of the elastic blades is substantially straight, and the second 32 comprises two notches 39 arranged to ensure friction on a part of the periphery of the shaft 30 at an angle at the center α less than 180 ° with respect to the axis of rotation D.

Figures 11 to 14 illustrate the assembly steps of another variant of brake mobile 10, this time single-blade, on a structure 1 provided with a lock 6, and through which structure 1 pivots a shaft 30, which is also guided with guide means (not shown), and which has to be braked. The braking mobile 10 is this time single-blade, it comprises a single elastic blade 3, forming an open loop 31, one branch of which is straight, or substantially straight, on the side of the support with the shaft 30. These figures illustrate a preferred variant where this branch is straight. The brake mobile 10 comprises, facing this right branch of the blade 3, a vee 33, delimited by two vertices 34, and, beyond the vee 33, a blind clearance 35, limited on the side opposite to the vee 33 by the attachment of the elastic blade 3 to the body of the braking mobile 10. This clearance 35 allows the angular movement of the elastic blade 3 between a completely free position visible in FIG. 12, and a position where its distal end comes into abutment against on the body of the braking mobile 10, as shown in FIG. 13; and this clearance 35 is further dimensioned to allow passage of the shaft 30 in an eccentric assembly position, visible in FIG. 12, for the relative axial insertion between the braking mobile 10 and the shaft 30. The elasticity of the blade 3 allows sufficient deflection to allow the crossing of a vertex 34 by the shaft 30, before its immobilization in the vee 33. In the service position of Figure 14, the shaft 30 carries a side on the vee 33 delimited by its two peaks 34, and is braked on the opposite side by the single elastic blade 3, the forks 7 of the braking mobile 10 grip the lock 6 with a slight play; this lock 6 can then be turned by a quarter of a turn, to limit the axial movement of the braking unit 10 relative to the structure 1.

More particularly, the braking mobile 10 is asymmetrical with respect to the axis of rotation D.

[0030] More particularly, the braking mobile 1 is in one piece and made of micromachinable material.

As regards the positioning latch 6, the latter is arranged to be fixed on an implantation that comprises the structure 1, by trapping the brake mobile 10, so as to allow it an axial play limited to a value axial bounded, in the direction of the axis D, and / or to allow it an angular play limited to a limited angular value, in a plane perpendicular to the axis D. Thus, the braking mobile 10 is not lined in structure 1, but positioned by this lock 6, which does not block the braking mobile 10. The lock 6 leaves a radial and axial degree of freedom to the braking mobile 10, so that the latter is self-locking. center and thus compensates for geometric variations. More particularly, this lock 6 consists of a screw within reach.

In a particular variant illustrated by the figures, the braking mobile 10 comprises, in a plane perpendicular to the axis D, a fork 7. This fork 7 is arranged to surround a bearing surface of the lock 6 with a clearance corresponding to the bounded angular value. An upper face of this fork 7 is arranged to cooperate in abutment bearing with at least one lower face, which a collar of the latch 6 comprises, to limit the axial travel of the braking mobile 10.

More particularly, this collar comprises, in a first direction, a narrow portion of width less than the opening of the fork 7, to allow the insertion of the braking mobile 10 on the shaft 30 near the lock 6 fixed in a first angular position of mobility, on the structure 1. The collar comprises, in a second direction preferably but not limited to orthogonal to the first direction, a wide part, which is of greater width than the opening of the fork 7 This wide part carries the lower face which axially immobilizes the fork 7 in a second angular locking position of the latch 6.

The lock 6 can be simply driven into the implantation of the structure 1, or mounted screwed, or with a bayonet connection, or the like. The axial play, like the radial play, is preferably, and not limited to, between 10 and 30 micrometers, more particularly between 15 and 25 micrometers.

In a particular variant, the rim of the brake mobile 10 comprises, in a plane perpendicular to the axis D, hollow clearances, diametrically opposed in pairs with respect to the axis D, and which are provided for the handling of the braking unit 10 by a robotic manipulator clamp, or for easy gripping by the tweezers of an operator.

The brake mobile 10 can be simply placed on a bearing surface of the structure 1, on which it is preferably held by the latch 6. In a particular variant, the rim 2 of the brake mobile 10 comprises, in a plane perpendicular to the axis D, radial stops which are arranged to cooperate in radial stop support with a recess that the structure 1 comprises, to limit the radial travel with respect to the axis of rotation D of the shaft 30. More particularly, these radial stops alternate with all or part of the clearances, when the braking mobile 10 includes them.

In a particular application of this clockwork mechanism 100, a mobile 40 is a small seconds display mobile, the shaft of which is generally rolled and slightly conical. The solution offered by the invention is well suited to this scenario, because of the moderate cost, the small size, the precision and the surface condition of the components present, and the easy assembly due to the cone of the mobile shaft.

In another variant, the structure 1 comprises a plurality of implantations, which are arranged for the pivoting of different shafts 30 of different mobiles 40, around the same implantation, which is arranged to receive a lock 6 capable of cooperate with a braking unit 10 arranged on any one of the shafts 30. Thus, for example, the system makes it possible to manage different small second center distances, while using the same components.

In yet another variant, the rim of the braking mobile 10 comprises a peripheral bearing surface which is arranged for, in a plane perpendicular to the axis D, to cooperate with clamping with a recess that comprises the structure 1.

[0040] In a particular embodiment, the braking mobile 10 is in one piece and made of micromachinable material, such as silicon, DLC, or the like. The manufacture by a lithographic or similar process guarantees high geometric precision, and a good surface condition, which is above all repetitive.

The invention also relates to a clockwork movement 200 comprising at least one such clockwork mechanism 1000.

[0042] A particular application of the invention relates to its application to a chronograph mechanism.

The invention also relates to a watch 300 comprising at least one such movement 200 and / or at least one such clockwork mechanism 1000.

In short, the use of a braking mobile, as described above, is particularly advantageous, because of the reproducibility of the behavior of the mobile, due to the manufacturing process of the braking mobile. The variation in frictional force, unacceptable in the prior art, is reduced, or even eliminated, which induces less variation in the rate. The assembly of the mechanism is, moreover, extremely easy. Finally, the cost of the braking device is reduced, its bulk in terms of thickness is very small, and this allows the inexpensive improvement of any existing mechanism with a loose gear and comprising a mobile, in particular a display mobile, of which stabilization is desired.

Claims (18)

1. Clockwork mechanism (1000) comprising a structure (1) carrying at least a first device (4) and / or a second device (5) for guiding in pivoting a shaft (30) of a movable (40) around an axis of rotation (D), and comprising at least one braking device (100) which is separate and distant, in the direction of said axis of rotation (D), from any pivoting guide device (4; 5) included in said mechanism (1000), said braking device (100) comprising at least one braking unit (10) comprising at least one elastic blade (3; 31; 32) arranged to exert a braking support mechanical on said shaft (30), characterized in that said at least one said braking mobile (10) extends substantially perpendicular to said axis of rotation (D), and is mounted captive between said structure (1) and a lock ( 6) that comprises said mechanism (1000) and is movable at least in a plane perpendicular to said axis of rotation (D), with respect to the said structure (1) and said tree (30), and in that, - or all the supports on said shaft (30) of all said elastic blades (3; 31; 32) which said braking unit (10) comprises are exerted in a single angular sector at an angle at the center (a) less than 180 ° with respect to said axis of rotation (D), so as to allow relative mobility between said braking unit (10) and said shaft (30) in a direction of mobility included in said angular sector, - or else said braking mobile (10) comprises a first elastic blade (31) straight or convex arranged to tangentially brake said shaft (30) and whose direction defines a direction of mobility (DM) perpendicular to said axis of rotation (D) , and, on the side opposite to said first elastic blade (31) relative to said axis of rotation (D), at least one second elastic blade (32) which is arranged to allow relative mobility between said braking mobile (10) and said shaft (30) in said direction of mobility (DM), said second elastic blade (32) being: o either single, and straight or convex, and arranged to tangentially brake said shaft (30) parallel to said first elastic blade (31), o is wavy in the manner of a hairpin and comprising at least one elastic notch (39) deformable in a direction perpendicular to said axis of rotation (D) and to said direction of mobility (DM). 2. Watch mechanism (1000) according to claim 1, characterized in that said structure (1) carries a first device (4) and a second device (5) for guiding said shaft (30) in pivoting. ) around said axis of rotation (D), distinct and distant from each other and from said braking device (100). 3. Watch mechanism (1000) according to claim 1 or 2, characterized in that said structure (1) carries a first device (4) for guiding said shaft (30) in pivoting, which first device (4) ) guide comprises, either a first bearing (40) of said structure (1) cooperating in a complementary manner with a first bearing (41) of said shaft (30), or a first anchor (45) carrying a first guide flexible (46) to which said shaft (30) is suspended or to which said shaft (30) is integral. 4. Clock mechanism (1000) according to one of claims 1 to 3, characterized in that said structure (1) carries a second device (5) for guiding said shaft (30) in pivoting, which second guide device (5) comprises, either a second bearing (50) of said structure (1) cooperating in a complementary manner with a second bearing (51) of said shaft (30), or a second anchor (55) carrying a second flexible guide (56) from which said shaft (30) is suspended or from which said shaft (30) is integral. 5. Clockwork mechanism (1000) according to one of claims 1 to 4, characterized in that said braking mobile (10) has axial mobility, with a first axial play, in the direction of said axis of rotation (D ), relative to said structure (1) and to said shaft (30). 6. Clockwork mechanism (1000) according to one of claims 1 to 5, characterized in that said braking mobile (10) is arranged to apply mechanical braking at constant torque on said shaft (30). 7. Clockwork mechanism (1000) according to one of claims 1 to 6, characterized in that said braking mobile (10) comprises at least one anti-shock stop (22; 23) which is arranged to limit the stroke. relative between said braking mobile (10) and said shaft (30) according to said direction of mobility (DM). 8. Clockwork mechanism (1000) according to claim 7, characterized in that said braking mobile (10) comprises at least two said anti-shock stops (22, 23), arranged on either side of said shaft ( 30). 9. Clockwork mechanism (1000) according to one of claims 1 to 8, characterized in that at least one said mobile braking device (10) comprises two parallel blades (31, 32) arranged to allow its radial insertion around of said shaft (30). 10. Clock mechanism (1000) according to one of claims 1 to 8, characterized in that at least one said mobile braking device (10) comprises two convex blades (31, 32) arranged to allow its radial insertion around of said shaft (30). 11. Clockwork mechanism (1000) according to one of claims 1 to 8, characterized in that said braking mobile (10) comprises two said elastic blades (31, 32) arranged on either side of said shaft ( 30) and together forming a hairpin spring comprising at least one said elastic notch (39). 12. Timepiece mechanism (1000) according to claim 11, characterized in that the first (31) of said elastic blades is substantially straight, and in that the second (32) comprises two said notches (39) arranged to ensure a friction on a part of the periphery of said shaft (30) at an angle at the center (a) less than 180 ° with respect to said axis of rotation (D). 13. Timepiece mechanism (1000) according to one of claims 1 to 8, characterized in that said braking mobile (10) comprises a said elastic blade (3) single facing a vee (33) delimited by two tops (34), and comprises a clearance (35) arranged to allow the relative insertion of a said shaft (30), and to allow the movement of said elastic blade (3). 14. Clockwork mechanism (1000) according to one of claims 1 to 13, characterized in that said braking mobile (10) is asymmetrical with respect to said axis of rotation (D). 15. Clockwork mechanism (1000) according to one of claims 1 to 14, characterized in that said braking mobile (1) is in one piece and made of micromachinable material. 16. Timepiece mechanism (1000) according to one of claims 1 to 15, characterized in that a said mobile (40) is a small second display mobile. 17. Timepiece movement (200) comprising at least one timepiece mechanism (1000) according to one of claims 1 to 16. 18. Watch (300) comprising at least one timepiece mechanism (1000) according to one of claims 1 to 17.