Disengageable winding device, in particular of a timepiece barrel, provided with a sliding winding gear train

Abstract

The invention relates to a disengageable winding device (1), in particular a barrel (2) equipped with a spring, comprising a ratchet (3) fixedly mounted on a winding shaft, the winding shaft being, for example, a winding shaft for the barrel (2) whose rotation winds the barrel (2), and a winding train (40) meshing with the ratchet (3), the rotation of the winding train (40) causing the rotation of the ratchet (3) and that of the winding shaft, the winding device (10) comprising an actuating element (31) for driving the winding train (40) by applying a torque to the winding train (40), the actuating element (31) meshing with the winding train (40) in an engaged position, the winding train (40) being mounted to slide around of a rotating shaft (26) to be able to disengage from the engaged position when the torque applied to the winding gear (40) is significantly greater than a threshold value,particularly when the barrel (2) is fully wound. The invention also relates to a watch movement comprising such a winding device (1).

Description

Technical field of the invention

[0001] The invention relates to a disengageable winding device, in particular for a watch barrel, equipped with a sliding winding gear.

[0002] The invention also relates to a clockwork movement comprising such a disengageable winding device. Technological background

[0003] Most modern self-winding mechanical watches generally feature an oscillating weight that drives a gear train by gravity. The rotation of this gear train winds a mainspring, the barrel spring, which is wound in a drum around a shaft, by driving the shaft itself. The rotation is usually forced in only one direction and is prevented from reversing by a pawl.

[0004] However, when the spring is fully wound, over-winding must be avoided as it could cause the spring to break, or the oscillator to bounce back, during which the amplitude of oscillation increases to the point that the balance wheel comes to rest against the anchor horns, and causes a drift in rate due to the rebound of the balance wheel against these stops.

[0005] To avoid these risks, such cylinders generally have a system for limiting the winding of the cylinder spring.

[0006] This limitation is generally achieved by the outermost leaf of the spring sliding against the inner wall of the drum. When the spring is fully wound and coiled around the barrel's winding arbor, the last wound coil presses against the outer wall of the drum.

[0007] Thus, when the winding torque exceeds the friction torque against the wall of the last coil, the coil begins to slip. To prevent uncontrolled slippage, notches allow the blade end to stop sliding as soon as the winding torque has decreased sufficiently.

[0008] However, the drawback of such a system lies in the sliding and friction process of the last coil inside the drum. Indeed, when the driven mechanism requires significant torque, the pressure forces and friction of the spring leaf against the wall are increased, leading to wear and a degradation of the barrel's performance, even in the presence of grease, which is eventually washed away from the friction track.

[0009] Furthermore, within an automatic barrel, it is necessary to meet contradictory criteria to maximize efficiency, such as reduced friction between the coils, and significant friction between the spring and the drum to guarantee good winding torque.

[0010] Damage to the drum must also be avoided, such as the tearing off of the coating, the formation of sludge, and the wear of the walls under the pressure of the fully wound spring blade.

[0011] Document FR 1 207 713 describes a clutch device for a watch barrel. Summary of the invention

[0012] The aim of the present invention is to overcome all or part of the disadvantages mentioned above by proposing a winding device equipped with a system for limiting the winding of a spring, which replaces a system based on the sliding of a blade against notches in an internal wall of the drum.

[0013] To this end, the invention relates to a disengageable winding device, in particular of a barrel equipped with a spring, comprising a ratchet mounted rigidly on a winding shaft, the winding shaft being for example a winding shaft of the barrel whose rotation winds the barrel, and a winding gear meshing with the ratchet, the rotation of the winding gear causing the rotation of the ratchet and that of the winding shaft, the winding device comprising an actuating mobile for actuating the winding gear by applying a torque to the winding gear, the actuating mobile meshing with the winding gear in a engaged position.

[0014] The invention is remarkable in that the winding gear is mounted to slide so that it can move out of the engaged position when the torque applied to the winding gear is substantially greater than a threshold value, in particular when the barrel is fully wound.

[0015] Thus, the winding gear train can disengage from its position, so that the ratchet wheel is no longer driven by the winding gear train. Indeed, the winding gear train is no longer meshed with the actuating wheel. For example, when the torque applied to the winding gear train by the actuating wheel is too high, particularly when the mainspring barrel is fully wound, the winding gear train slips and no longer transmits the rotational torque to the ratchet wheel, so the ratchet wheel stops rotating.

[0016] Thanks to this invention, the risk of premature wear of the mainspring barrel is avoided, as the limiting device is positioned upstream and outside the barrel. Furthermore, it eliminates the need for conventional winding limiting devices, which rely on the friction of the spring inside the barrel.

[0017] According to the invention, the winding gear and the actuation mechanism are superimposed.

[0018] According to a particular embodiment of the invention, the actuating mechanism is mounted integrally with said rotating shaft.

[0019] According to a particular embodiment of the invention, the actuating mechanism does not mesh with the winding gear when the winding gear slides.

[0020] According to a particular embodiment of the invention, the winding device includes return means exerting an axial return force on the winding gear in the direction of the actuating mobile, to maintain it in the engaged position.

[0021] According to a particular embodiment of the invention, the return means comprise a spring arranged above the winding gear.

[0022] According to a particular embodiment of the invention, the winding gear slides when the torque applied to the winding gear generates an axial force greater than and opposite to the force exerted by the return means.

[0023] According to a particular embodiment of the invention, the actuating mechanism and the winding gear each have a wolf's tooth toothing, the two wolf's toothings cooperating with each other.

[0024] The invention also relates to a watch movement comprising a barrel, the watch movement having such a disengageable winding device for the barrel. Brief description of the figures

[0025] The aims, advantages and features of the present invention will become apparent from the reading of several embodiments given solely by way of non-limiting examples, with reference to the accompanying drawings in which: there figure 1 schematically represents a cross-sectional view of a disengageable winding device according to an embodiment of the invention, in the engaged position, the figure 2 schematically represents a cross-sectional view of the disengageable winding device according to the embodiment of the invention of the figure 1 , which is disengaged, the figure 3 schematically represents a perspective view of the disengageable winding device according to the embodiment of the invention of the figure 1, in the engaged position, the figure 4 schematically represents a perspective view of the disengageable winding device according to the embodiment of the invention of the figure 1 , which is disengaged, particularly when the mainspring of the cylinder is fully wound, and the figure 5 schematically represents an exploded perspective view of the disengageable winding device according to the embodiment of the invention of the figure 1 . Detailed description of the invention

[0026] THE figures 1 to 5 represent an embodiment of a winding device 10, here of a watch barrel 2, according to the invention.

[0027] The winding device 10 of the barrel 2 includes a ratchet 3 and a winding train 40. The winding train 40 meshes with the ratchet 3, so that when the winding train 40 is set in rotation in a first direction, the ratchet 3 is driven in rotation in a second direction opposite to the first direction.

[0028] The ratchet 3 is mounted rigidly on a winding shaft, the winding shaft enabling the winding of the barrel 2. The winding shaft is preferably cylindrical.

[0029] In the example, the winding shaft is the winding shaft of the barrel 2, the ratchet 3 being arranged on the barrel 2. The ratchet 3 includes a hub 7 mounted integrally on the winding shaft.

[0030] In a variant, not shown in the figures, the winding shaft is not mounted on the barrel, the winding shaft comprising a pinion engaging with a moving part driving the winding shaft of the barrel to wind the spring, if the ratchet is not mounted on the barrel.

[0031] The winding gear 40 is arranged next to the ratchet 3, and preferably extends in the same plane as the ratchet 3.

[0032] The ratchet 3 includes a first external toothing 11 distributed around the ratchet 3. The first toothing 11 cooperates with a second peripheral toothing 22 arranged on a first wheel 28 of the winding train 40. The winding train 40 includes a third toothing 25 arranged under the first wheel.

[0033] Barrel 2 contains a spiral spring (not shown in the figures), arranged inside barrel 2, which must be wound either by an automatic winding system or by a manual winding system.

[0034] To this end, the winding device 1 further comprises a gear train 23, for example driven by an automatic winding weight (not shown in the figures) of the watch movement. The gear train 23 can also be driven by a winding stem (not shown in the figures) operated by means of a crown, in the case of manual winding.

[0035] A drive mechanism 31 of the winding system of gears 23 drives the winding gear 40. The drive mechanism 31 includes a second wheel 29 having a fourth peripheral toothing 27 cooperating with another drive mechanism 32 of the gear system 23. The drive mechanism 31 includes a fifth toothing 24 arranged on the second wheel 29, and engaging with the third toothing 25 of the winding gear 40 in the engaged position.

[0036] Thus, by actuating the gear system 23, a torque is applied to the ratchet 3, which transmits it at least in part to the winding shaft, via the winding gear 40 driven by the actuating mobile 31.

[0037] The rotation of the actuating mobile 31 and the winding gear 40 causes the rotation of the ratchet 3, and therefore of the winding shaft, when the barrel 2 is wound.

[0038] To avoid over-winding the barrel 2, the winding gear 40 is mobile from a engaged position in which it drives the ratchet 3.

[0039] In this embodiment, the disengageable winding device 10 comprises a rotating shaft 26, on which the winding gear 40 is mounted to slide around said rotating shaft 26. The actuating mobile 31 is fixedly mounted on the rotating shaft 26.

[0040] The winding gear 40 engages with the winding drive wheel 31 when it is in the engaged position, and it does not engage with the winding drive wheel 31 when it slides along the rotating shaft 26.

[0041] Thus, in the engaged position, the actuating mobile 31 drives the winding gear 40, and the winding gear 40 drives the ratchet 3.

[0042] Whereas after the sliding of the winding gear 40, the actuating mobile 31 rotates freely and does not drive the winding gear 40, which is at a distance from the actuating mobile 31. Thus, the ratchet 3 is no longer driven by the winding gear 40.

[0043] The winding gear 40 and the drive wheel 31 are superimposed, one above the other. The winding gear 40 is arranged above the drive wheel 31, so that the fifth tooth 24 of the drive wheel 31 cooperates with the third tooth 25 of the winding gear 40 in the engaged position.

[0044] The third and fifth teeth preferably have wolf-tooth shaped teeth. In other words, one side of each tooth is less angled than the other. This allows the teeth to slide more easily against each other in a preferred direction of rotation if they are not held tightly together.

[0045] The winding gear 40 can slide axially along the axis of the rotating shaft 26. Thus, the winding gear 40 can make an axial displacement from the engaged position, and vice versa.

[0046] In the engaged position, the winding gear 40 and the drive wheel 31 are in contact via the third 25 and fifth 24 teeth, which mesh with each other. Thus, the drive wheel 31 drives the winding gear 4, and therefore the ratchet wheel 3.

[0047] In the disengaged configuration, the winding gear 40 and the drive wheel 31 are further apart, so that the third 25 and fifth 24 teeth do not mesh. Thus, the drive wheel 31 does not drive the winding gear 4, nor the ratchet wheel 3.

[0048] Furthermore, the second tooth 22 of the winding gear 40 no longer meshes with the first tooth 11 of the ratchet wheel 3 when the winding gear 40 is disengaged. This is because, as the winding gear 40 has slid along the rotating shaft 26, the second tooth 22 has shifted beyond the first tooth 11.

[0049] The winding device 40 further includes return means 50 exerting an axial return force on the winding gear 40 in the direction of the actuating mobile 31, to maintain it in the engaged position.

[0050] The return means comprise a spring (30) arranged above the winding gear (40).

[0051] The winding gear 40 is mounted on the spring 30, which exerts an axial force on the winding gear 40 to keep it in the engaged position.

[0052] The spring 30 has a flexible collar shape assembled to the rotating shaft 26, above the winding gear 40. The flexible collar is curved or folded over the winding gear 40 to press against it.

[0053] The flexible collar exerts an axial restoring force on the winding gear 40 in the direction of the actuating mobile 31, so that the third 25 and the fifth 24 teeth cooperate in the engaged position.

[0054] In addition, the winding gear 40 slides around the winding shaft 26, when the torque applied to the winding gear 40 generates an axial force opposite and greater than the force exerted by the return means 50.

[0055] Indeed, thanks to the shape of the wolf's teeth of the third 25 and fifth 24 teeth, the torque applied to the winding gear 40 generates a force pushing the winding gear 40 in a direction opposite to the force produced by the spring 30.

[0056] Thus, when the torque significantly exceeds a threshold value, the winding gear 40 slides around the rotating shaft 26 to disengage from the engaged position. The winding gear 40 slides by making a substantially rectilinear axial movement around the rotating shaft 26 from the engaged position to a certain distance from the actuating element 31.

[0057] Beyond the threshold value, when the torque required to rotate the ratchet 3 is higher than that required to unfold the flexible collar 26 upwards, the winding gear 40 is pushed by the actuating mobile 31 by means of the third 25 and the fifth 24 teeth, in particular by means of the wolf's teeth 24, 25.

[0058] In other words, when the actuation mobile 31 presses hard on the winding gear 40, the third 25 and the fifth wolf's tooth 24 slide over each other without meshing and the winding gear 40 moves because the flexible collar extends as it moves up along the rotating shaft 26.

[0059] Therefore, the drive wheel 31 continues to rotate, but the winding gear 40 and the ratchet 3 no longer rotate.

[0060] On the Figures 1 And 3 In the winding configuration, the winding torque exerted on the winding train 40 by the actuating wheel 31 is less than the threshold value, so the flexible collar does not change shape. Thus, the first tooth 12 and the ratchet wheel 3 are driven by the winding train 40.

[0061] On the figures 2 And 4When the barrel 2 is fully wound, the winding torque exerted on the winding train 40 by the actuating wheel 31 exceeds the threshold value, causing the flexible collar to unfold and the winding train 40 to move upwards. In other words, the torque required to rotate the ratchet wheel 3 is too great for the flexible collar, which cannot remain in its initial position.

[0062] These disengagement mechanisms protect barrel 2 from over-winding and prevent premature wear inside barrel 2. The winding shaft can thus be blocked when the mainspring of the mainspring is fully wound, without risking breaking the mainspring of barrel 2.

[0063] The barrel 2 also includes a sixth peripheral toothed tooth 18 configured to cooperate with a seventh toothed tooth of a moving part of the watch movement. The moving part is, for example, a center wheel. Once wound, the barrel 2 supplies the energy necessary for the operation of the watch movement via the moving part.

[0064] The invention also relates to a clockwork movement, not shown in the figures, the movement comprising a barrel and a barrel winding device as described above.

[0065] Naturally, the invention is not limited to the embodiments described with reference to the figures and variants could be envisaged without departing from the scope of the invention as defined by the annexed claims.

Claims

1. Disengageable winding device (10), in particular for a barrel (2) provided with a spring, comprising a ratchet (3) mounted on a winding arbor such that it is rigidly connected thereto, the winding arbor being, for example, an arbor for winding the barrel (2), the rotation of which winds up the barrel (2), and a winding gear train (40) meshing with the ratchet (3), the rotation of the winding gear train (40) driving the rotation of the ratchet (3) and of the winding arbor, the winding device (10) comprising an actuating wheel set (31) for driving the winding gear train (40) by applying a torque to the winding gear train (40), the actuating wheel set (31) meshing with the winding gear train (40) in an engaged position, the winding gear train (40) being mounted so that it can slide about a rotary arbor (26) out of the engaged position when the torque applied to the winding gear train (40) is substantially greater than a threshold value, in particular when the barrel (2) is fully wound up, the winding gear train (40) and the actuating wheel set (31) being superimposed in the engaged position.

2. Winding device according to claim 1, characterised in that the actuating wheel set (31) is mounted on said rotary arbor (26) such that it is rigidly connected thereto.

3. Winding device according to claim 1 or 2, characterised in that the actuating wheel set (31) does not mesh with the winding gear train (40) when the winding gear train (4) is sliding.

4. Winding device according to any one of the preceding claims, characterised in that it comprises return means (50) exerting an axial return force on the winding gear train (40) in the direction of the actuating wheel set (31), to hold it in the engaged position.

5. Winding device according to claim 4, wherein the return means comprise a spring (30) arranged above the winding gear train (40).

6. Winding device according to claim 4 or 5, wherein the winding gear train (40) slides when the torque applied to the winding gear train (40) generates an axial force which is opposite to and greater than the force exerted by the return means (50).

7. Winding device according to any one of the preceding claims, characterised in that the actuating wheel set (31) and the winding gear train (40) each comprise a wolf-tooth toothing (24, 25), the two wolf-tooth toothings (24, 25) cooperating with each other.

8. Winding device according to claim 7, wherein the winding gear train (40) and the actuating wheel set (31) each comprise a second radial toothing (22, 27).

9. Horological movement comprising a barrel (2) and a winding device (10) for winding the barrel (2) according to any one of the preceding claims.

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