LIFTING DEVICE FOR A CLOCK SPRING HOUSE, WITH A COUPLING DEVICE

Description

Technical field of the invention

[0001] The invention relates to a winding device, in particular for a watch barrel, equipped with disengagement means.

[0002] The invention also relates to a clockwork movement comprising such a 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 the drum of this gear train winds a mainspring, the barrel spring, which is wound inside a drum around an axle. This winding action drives the axle. 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 swing back, during which the amplitude of oscillation increases to the point that the balance wheel comes to rest against the reverse of 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, such as coating tearing, sludge buildup, and wear on the walls under the pressure of the fully wound spring, must also be prevented. Some documents have already addressed this issue, such as EP3220206A1 and FR1354488A. Summary of the invention

[0011] 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.

[0012] To this end, the invention relates to a winding device, in particular for a watch barrel equipped with a spring, comprising a ratchet mounted on a rotating winding shaft, the rotating 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 rotating winding shaft by applying a torque on the ratchet, the winding device being equipped with means for disengaging the ratchet and the rotating winding shaft.

[0013] The invention is remarkable in that the disengagement means are arranged on the ratchet and the rotating winding shaft, and are configured to disengage the ratchet and the winding shaft when the torque applied to the ratchet substantially exceeds a threshold value, in particular when the barrel is fully wound.

[0014] Thus, when the winding torque is too high, the ratchet wheel disengages from the rotating barrel arbor and no longer transmits the ratchet wheel's rotational torque to the barrel arbor. As a result, the ratchet wheel continues to rotate, driven by the winding train, but the barrel arbor no longer rotates.

[0015] Thanks to this invention, the risk of premature wear of the cylinder is avoided, as the limiting device is positioned upstream and outside the cylinder. Furthermore, it eliminates the need for conventional winding limiting devices, which rely on spring friction inside the cylinder.

[0016] According to the invention, the disengagement means comprise a plurality of flexible pawls and a first toothing, the flexible pawls cooperating with the first toothing to transmit the ratchet torque to the rotating winding shaft to rotate it.

[0017] According to the invention, the flexible pawls engage with the first toothing when the torque is less than the threshold value.

[0018] According to a particular embodiment of the invention, the flexible pawls bend when the torque is substantially greater than the threshold value, so that the flexible pawls no longer mesh with the first toothing, the rotation of the ratchet no longer driving the rotating winding shaft.

[0019] According to the invention, the first toothing is arranged on the rotating winding shaft and the flexible pawls are arranged on the ratchet.

[0020] According to a particular embodiment of the invention, the ratchet comprises a hub on which the flexible pawls are arranged, the flexible pawls extending towards the rotating winding shaft.

[0021] According to a particular embodiment of the invention, the rotating winding shaft is arranged through the ratchet hub, the first toothing being arranged around the rotating winding shaft at the hub.

[0022] According to a particular embodiment of the invention, the flexible pawls are distributed angularly around the rotating winding shaft.

[0023] According to a particular embodiment of the invention, each ratchet comprises a flexible blade and a tooth arranged at the free end of the flexible blade, the teeth of the flexible ratchets cooperating with the first toothing.

[0024] According to a particular embodiment of the invention, the ratchet comprises a peripheral rim provided with a second peripheral toothing cooperating with a third toothing of the winding gear.

[0025] According to a particular embodiment of the invention, the ratchet is mounted on the barrel.

[0026] According to a particular embodiment of the invention, the rotating winding shaft is the winding shaft of the barrel which allows the barrel spring to be wound.

[0027] The invention also relates to a watch movement comprising a barrel, the watch movement having such a barrel winding device. Brief description of the figures

[0028] 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 top view of a winding device according to an embodiment of the invention, in the engaged position, and the figure 2schematically represents a top view of the winding device according to the embodiment of the invention of the figure 1 , in the disengaged position, particularly when the barrel spring is fully wound. Detailed description of the invention

[0029] THE figures 1 and 2 represent an embodiment of a winding device 1, here of a watch barrel 2, according to the invention.

[0030] The winding device 1 of the barrel 2 includes a ratchet 3 and a winding train 4. The winding train 4 meshes with the ratchet 3, so that when the winding train 4 is set in rotation in a first direction, the ratchet 3 is driven in rotation in a second direction opposite to the first direction.

[0031] The ratchet 3 is mounted on a winding shaft 5, the winding shaft 5 enabling the winding of the barrel 2. In the example, the winding shaft 5 is the winding shaft of the barrel 2, the ratchet being mounted on the barrel 2.

[0032] In a variant which is not part of the invention, not shown, 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.

[0033] The winding shaft 5 is preferably cylindrical. A first set of teeth 6 is arranged around the winding shaft 5.

[0034] The ratchet 3 comprises a hub 7 and a peripheral rim 8, the hub 7 being arranged inside the peripheral rim 8. The hub 7 and the peripheral rim 8 have the shape of circular rings, the hub 7 having a smaller radius than that of the peripheral rim 8. The hub 7 and the peripheral rim 8 are connected by at least one arm, here four arms 9 distributed angularly around the hub 7. The hub 7 and the peripheral rim 8 preferably extend in the same plane.

[0035] The hub 7 defines an internal space through which the winding shaft 5 passes at least partially.

[0036] The peripheral rim 8 includes a second external toothing 11 distributed along the peripheral rim 8 around the ratchet 3. The second toothing 11 cooperates with a third toothing 12 arranged on the winding train 4. The winding train 4 includes a pinion having the third toothing 12 arranged on its periphery.

[0037] Barrel 2 contains a mainspring, known as the "barrel spring," wound in a spiral shape (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

[0038] To this end, the winding device 1 further comprises a gear train 13, for example driven by an automatic winding weight (not shown in the figures) of the watch movement. The gear train 13 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.

[0039] A mobile 21 of the gear system 13 meshes with the third tooth 12 of the winding gear 4. Thus, by actuating the gear system 13, a torque is applied to the ratchet 4, which transmits it at least in part to the winding shaft 5 via the winding gear 4 driven by the mobile 21, and via the ratchet 3 driven by the winding gear 4.

[0040] According to the invention, the winding device 1 comprises disengagement means 10 for the ratchet and the winding shaft. The disengagement means 10 comprise the first set of teeth 6 arranged around the winding shaft 5, preferably on the same level corresponding to that of the ratchet 3.

[0041] The disengagement means 10 also include a plurality of flexible pawls 15 extending from the hub 7 to the winding shaft 5. The flexible pawls 15 are angularly distributed inside the hub 7, in the plane of the ratchet 3. The flexible pawls 15 cooperate with the first toothing 6, so that the rotation of the ratchet 3 causes the rotation of the winding shaft 5, when the barrel 2 is wound.

[0042] Each pawl 15 includes a flexible blade 16 extending from the hub 7 of the ratchet 3. At the free end of each flexible blade 16, there is a tooth 17 capable of cooperating with the first tooth 6 of the winding shaft 5. During winding, the teeth 17 of the flexible pawls 15 are inserted into the first tooth 6 to rotate it.

[0043] The disengagement means 10 include at least one flexible ratchet 15, preferably at least four flexible ratchets. The number of flexible ratchets 15 depends on the flexibility of the flexible blades 16, and on the threshold torque value beyond which the disengagement means 10 are configured to disengage the ratchet 3 and the winding shaft 5.

[0044] In this embodiment, the disengagement means 10 comprise sixteen flexible pawls 15 distributed around the winding shaft.

[0045] The flexible blades 16 are configured to bend beyond a torque threshold typically required to wind the barrel. Thus, beyond a certain threshold value, when the torque is too high, the flexible blades 16 bend, causing the teeth 17 of the flexible pawls 15 to slip from the first tooth without engaging it. Consequently, the winding arbor 5 no longer rotates despite the rotation of the ratchet wheel 3.

[0046] On the figure 1 In the winding configuration, the winding torque exerted on the winding shaft by the ratchet 3 is less than the threshold value, so that the flexible blades 16 of the flexible pawls 15 remain substantially straight. Thus, the flexible pawls 15 drive the winding shaft 5 via the first tooth 6.

[0047] On the figure 2 When the barrel 2 is fully wound, the torque exerted on the winding shaft 5 by the ratchet wheel 3 exceeds the threshold value, causing the flexible blades 16 of the flexible pawls 15 to bend. In other words, the torque required to rotate the winding shaft 5 becomes too great for the flexible pawls, which then bend. Consequently, the teeth 17 of the flexible pawls 15 no longer have sufficient grip on the first tooth 6 to drive the winding shaft 5.

[0048] These disengagement mechanisms protect cylinder 2 from over-cocking and prevent premature wear inside cylinder 2.

[0049] The barrel 2 also includes a fourth peripheral toothed section 18 configured to cooperate with a fifth toothed section 19 of a moving part 20 of the clockwork mechanism. The moving part 20 is, for example, a center wheel, a center wheel, or even a striking wheel. Once wound, the barrel 2 supplies the energy necessary for the operation of the clockwork mechanism via the moving part 20.

[0050] 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.

[0051] 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.

[0052] For example, in the implementation of figures 1 and 2 , the flexible pawls 15 are arranged on the ratchet 3 and the first toothing 6 is arranged on the winding shaft 5.

[0053] However, in another embodiment, not shown, it is possible to arrange the flexible pawls on the winding shaft and to fit a first set of teeth inside the ratchet hub. The flexible blades of the flexible pawls extend from the winding shaft to the ratchet hub so as to cooperate with the first set of teeth.

[0054] Thus, as long as the torque exerted on the flexible pawls is less than a threshold value, the ratchet drives the winding shaft, and when the torque exerted on the flexible pawls exceeds the threshold value, the flexible blades bend and no longer mesh with the first tooth, the ratchet turning without driving the winding shaft.

Claims

1. A winding device (1), in particular for a barrel (2) provided with a spring, comprising a ratchet (3) mounted on a rotary winding shaft (5), the rotary winding shaft (5) being, for example, a winding shaft of the barrel (2), the rotation of which coils the barrel (2), and a winding gear train (4) meshing with the ratchet (3), the rotation of the winding gear train (4) causing the rotation of the ratchet (3) and that of the rotary winding shaft (5) by applying a torque to the ratchet (3), the winding device (1) being provided with means (10) for disconnecting the ratchet (3) and the rotary winding shaft (5), the disconnection means (10) being arranged on the ratchet (3) and on the rotary winding shaft (5), and are configured to disconnect the ratchet (3) and the rotary winding shaft (5) when the torque applied to the ratchet (3) substantially exceeds a threshold value, in particular when the barrel (2) is fully coiled, the disconnection means (10) comprise a plurality of flexible pawls (15) and a first set of teeth (6), the flexible pawls (15) cooperating with the first set of teeth (6) to transmit the torque from the ratchet (3) to the rotary winding shaft (5) to cause it to rotate, characterised in that the first set of teeth (6) is arranged on the rotary winding shaft (5) and the flexible pawls (15) are arranged on the ratchet (3).

2. The winding device according to claim 1, characterised in that the flexible pawls (15) engage with the first set of teeth (6) when the torque is below the threshold value.

3. The winding device according to claim 1 or 2, characterised in that the flexible pawls (15) bend when the torque is substantially greater than the threshold value, so that the flexible pawls (15) no longer mesh with the first set of teeth (6), the rotation of the ratchet (3) no longer driving the rotary winding shaft (5).

4. The winding device according to any one of the preceding claims, characterised in that the rotary winding shaft (5) is arranged through the hub (7) of the ratchet (3), the first set of teeth (6) being arranged around the rotary winding shaft (5) at the hub.

5. The winding device according to any one of the preceding claims, characterised in that the flexible pawls (15) are angularly distributed around the rotary winding shaft (5).

6. The winding device according to any one of the preceding claims, characterised in that each pawl (15) comprises a flexible leaf (16) and a tooth (17) arranged at the free end of the flexible leaf (16), the teeth (17) of the flexible pawls (15) cooperating with the first set of teeth (6).

7. The winding device according to any one of the preceding claims, characterised in that the ratchet (3) comprises a peripheral rim (8) provided with a second peripheral set of teeth (11) cooperating with a third set of teeth (12) of the winding gear train (4).

8. The winding device according to any one of the preceding claims, characterised in that the ratchet (3) is mounted on the barrel (2).

9. The winding device according to any one of the preceding claims, characterised in that the rotary winding shaft (5) is the winding shaft of the barrel (2) allowing to coil the barrel (2) spring.

10. A horological movement comprising a barrel (2) and a barrel (2) winding device (1) according to any one of the preceding claims.