Winding device, in particular for a timepiece barrel, provided with a disengageable ratchet
The deformable ratchet mechanism in self-winding watches addresses over-winding issues by disengaging from the gear train at high torque, preventing wear and maintaining barrel efficiency.
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Patents
- Current Assignee / Owner
- NIVAROX FAR SA
- Filing Date
- 2022-11-24
- Publication Date
- 2026-05-20
AI Technical Summary
Existing self-winding mechanical watches face issues with over-winding, leading to premature wear and degradation of the barrel due to increased friction and pressure, which conventional limiting systems cannot effectively address.
A deformable ratchet mechanism is introduced that disengages from the winding gear when excessive torque is applied, preventing over-winding and reducing friction-related wear by positioning the limiting device outside the cylinder.
The deformable ratchet mechanism effectively prevents over-winding, reducing wear and maintaining barrel performance by eliminating the need for internal friction-based limiting systems.
Smart Images
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Abstract
Description
Technical field of the invention
[0001] The invention relates to a winding device, in particular for a watch barrel, equipped with a disengageable ratchet.
[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 driving a gear train by gravity, the rotation of whose drum winds a mainspring, the barrel spring, wound in a drum around an axis, by driving said axis.
[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 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] EP 3 220 206 A1 discloses a device according to the preamble of claim 1. 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 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.
[0014] The invention is remarkable in that the ratchet is deformable in order to disengage the ratchet from the winding gear.
[0015] Thus, by deforming, the ratchet wheel is no longer driven by the winding gear train, because the latter no longer engages the ratchet wheel. For example, when the torque applied to the ratchet wheel is too high, particularly when the barrel is fully wound, the ratchet wheel deforms and disengages from the winding gear train, which no longer transmits the rotational torque to the ratchet wheel, so that the winding gear train continues to rotate, but the ratchet wheel no longer rotates.
[0016] 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.
[0017] According to a particular embodiment of the invention, the ratchet comprises a first peripheral toothing cooperating with a second toothing of the winding gear, when the torque applied to the ratchet is substantially less than a threshold value.
[0018] According to a particular embodiment of the invention, the ratchet deforms when the torque applied to the ratchet substantially exceeds said threshold value, in particular when the barrel is fully cocked, so that the first peripheral toothing no longer cooperates with the second toothing.
[0019] According to a particular embodiment of the invention, the ratchet comprises a plurality of flexible pawls forming the first toothing of the ratchet, the flexible pawls engaging with the second toothing when the torque is less than the threshold value.
[0020] 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 second toothing, the rotation of the winding gear no longer driving the ratchet.
[0021] According to a particular embodiment of the invention, the ratchet comprises a hub on which the flexible pawls are arranged, the flexible pawls extending around the hub.
[0022] 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 second set of teeth.
[0023] According to a particular embodiment of the invention, the flexible pawls are distributed angularly around the ratchet.
[0024] According to a particular embodiment of the invention, the ratchet comprises a peripheral rim, preferably rigid, provided with the first teeth.
[0025] According to a particular embodiment of the invention, the ratchet comprises a hub, the peripheral rim being connected to the hub by at least one spring, preferably several connecting springs.
[0026] According to a particular embodiment of the invention, the connecting spring(s) contract or stretch when the torque is substantially greater than the threshold value, so that the peripheral rim is moved away from the winding gear, the rotation of the winding gear no longer driving the ratchet.
[0027] According to a particular embodiment of the invention, the connecting springs are distributed angularly around the hub.
[0028] According to a particular embodiment of the invention, the connecting spring(s) are one or more flexible blades.
[0029] According to a particular embodiment of the invention, the ratchet is mounted on the barrel, the rotating winding shaft being the barrel winding shaft enabling the barrel spring to be wound.
[0030] 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
[0031] 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 1schematically represents a top view of a winding device according to a first embodiment of the invention, in the engaged position, the figure 2 schematically represents a top view of the winding device according to the first embodiment of the invention of the figure 1 , in the disengaged position, particularly when the mainspring of the barrel is fully wound, the figure 3 schematically represents a top view of a winding device according to a second embodiment of the invention, in the engaged position, and the figure 4 schematically represents a top view of the winding device according to the second embodiment of the invention of the figure 3 , in the disengaged position, particularly when the barrel spring is fully wound. Detailed description of the invention
[0032] THE figures 1 and 2represent a first embodiment of a winding device 1, here of a watch barrel 2, according to the invention.
[0033] 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.
[0034] 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.
[0035] 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.
[0036] 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.
[0037] The ratchet 3 includes a first external toothing 11 distributed around the ratchet 3. The first toothing 11 cooperates with a second toothing 12 arranged on the winding gear 4. The winding gear 4, which is for example a pinion in this embodiment, is provided with the second toothing 12 arranged on its periphery.
[0038] 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.
[0039] 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.
[0040] A mobile 21 of the gear system 13 meshes with the second toothing 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 via the winding gear 4 driven by the mobile 21, and via the ratchet 3 driven by the winding gear 4.
[0041] According to the invention, the ratchet 3 is deformable so as to be able to disengage the ratchet 3 and the winding gear 4. In particular, the ratchet 3 deforms when the torque applied to the ratchet 3 substantially exceeds a threshold value, in particular when the barrel 2 is fully wound, so that the first peripheral toothing 11 no longer cooperates with the second toothing 12.
[0042] To this end, the ratchet wheel 3 has a plurality of flexible pawls 15 extending outwards from the hub 7. The flexible pawls 15 are angularly distributed around the hub 7, in the plane of the ratchet wheel 3. The flexible pawls 15 cooperate with the second set of teeth 12, so that the rotation of the winding train 4 causes the rotation of the ratchet wheel 3, and therefore of the winding arbor, when the barrel 2 is wound.
[0043] Each pawl 15 comprises a flexible blade 16 extending from the hub 7 of the ratchet 3. At the free end of each flexible blade 16 is arranged a tooth 17 capable of cooperating with the second tooth 12 of the winding shaft. The teeth 17 of the pawls 15 form the first tooth 11 cooperating with the second tooth 12. During winding, the teeth 17 of the flexible pawls 15 can engage with the first tooth 11 to rotate the ratchet 3.
[0044] The disengagement means 10 preferably include at least eight flexible pawls 15, preferably at least fifteen flexible pawls 15. The number of flexible pawls 15 depends on the flexibility of the flexible blades 16, and on the threshold value of the torque beyond which the disengagement means 10 are configured to disengage the ratchet 3 and the winding shaft.
[0045] In this embodiment, the ratchet 3 comprises thirty-two flexible pawls 15 distributed around the hub 7 and the winding shaft.
[0046] The flexible blades 16 are configured to bend beyond a torque threshold usually required to cock the cylinder. Thus, beyond a threshold value, when the torque is too high, the flexible blades 16 bend, so that the teeth 17 of the flexible pawls 15 disengage from the path of the second toothing 12 and the flexible pawls 15 are no longer driven by the second toothing 12.
[0047] In other words, when the winding gear 4 presses hard on one or more flexible pawls 15, the latter bend and move away from the second tooth 12. Consequently, the ratchet 3 no longer rotates despite the rotation of the winding gear 4.
[0048] On the figure 1In the winding configuration, the winding torque exerted on the ratchet 3, and in particular on the flexible pawls 15, 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 and the ratchet 3 are driven by the winding train 4. The first peripheral toothing 11 cooperates with a second toothing 12 of the winding train 4 when the torque applied to the ratchet 3 is substantially less than a threshold value.
[0049] On the figure 2 When the barrel 2 is fully wound, the winding torque exerted on the ratchet pawls by the winding train 4 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 ratchet 3 is too great for the flexible pawls, which cannot remain straight.
[0050] Consequently, the teeth 17 of the flexible pawls 15 in contact with the winding gear 4 are spread apart, the second tooth 12 of the winding gear 4 no longer having a grip on the first tooth 11, to drive the ratchet 3. The first peripheral tooth 11 no longer cooperates with the second tooth 12. The winding gear 4 continues to rotate, but the ratchet 3 no longer rotates.
[0051] These disengagement mechanisms protect cylinder 2 from over-cocking and prevent premature wear inside cylinder 2.
[0052] The barrel 2 also includes a third peripheral toothed section 18 configured to cooperate with a fourth 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.
[0053] THE figures 3 and 4 represent a second embodiment of a winding device 1, here of a watch barrel 2, according to the invention.
[0054] The winding device 1 of the barrel 2 includes a ratchet 30 and a winding train 4. The winding train 4 meshes with the ratchet 30, so that when the winding train 4 is set in rotation in a first direction, the ratchet 30 is driven in rotation in a second direction opposite to the first direction.
[0055] The ratchet 30 is mounted rigidly on a winding shaft, the winding shaft enabling the winding of the barrel 2. The winding shaft is preferably cylindrical.
[0056] In the example, the winding shaft is the winding shaft of barrel 2, ratchet 30 being arranged on barrel 2. Ratchet 30 includes a hub 7 mounted integrally on the winding shaft.
[0057] In a variant, 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.
[0058] The ratchet 30 includes a first external toothing 11 distributed around the ratchet 30. The first toothing 11 cooperates with a second toothing 12 arranged on the winding train 4. The winding train 4 here includes a pinion equipped with the second toothing 12 arranged at its periphery.
[0059] 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.
[0060] 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.
[0061] A mobile 21 of the gear system 13 meshes with the second 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 via the winding gear 4 driven by the mobile 21, and via the ratchet 30 driven by the winding gear 4.
[0062] According to the invention, the ratchet 30 is deformable so as to be able to disengage the ratchet 30 and the winding gear 4. In particular, the ratchet 30 deforms when the torque applied to the ratchet 30 substantially exceeds a threshold value, in particular when the barrel 2 is fully wound, so that the first peripheral toothing 11 no longer cooperates with the second toothing 12.
[0063] To this end, the ratchet 30 comprises a hub 27 and a peripheral rim 8, preferably rigid, the hub 27 being arranged inside the peripheral rim 8. The hub 27 and the peripheral rim 8 have the shape of circular rings, the hub 27 having a smaller radius than that of the peripheral rim 8. The hub 27 and the peripheral rim 8 preferably extend in the same plane.
[0064] The peripheral rim 8 includes the first external toothing 11 distributed along the peripheral rim 8 around the ratchet 30.
[0065] The hub 27 and the peripheral rim 8 are connected by at least one connecting spring 9, preferably several connecting springs distributed angularly around the hub 27. The connecting spring(s) 9 are for example one or more flexible serpentine leaves.
[0066] The number of flexible arms 15 depends on the flexibility of the flexible blades 16 and the threshold torque value beyond which the disengagement means 10 are configured to disengage the ratchet 30 and the winding shaft. In this embodiment, the ratchet 30 comprises four connecting springs 9 arranged at the four cardinal points.
[0067] The linking spring(s) 9 are configured to contract or stretch when the torque is substantially greater than the threshold torque value usually required to wind the barrel 2, so that the peripheral rim 8 is away from the winding gear 4.
[0068] In other words, when the winding gear 4 presses hard on the peripheral rim 8, the latter moves away from the second tooth 12.
[0069] Consequently, the first tooth 11 no longer meshes with the second tooth 12, the rotation of the winding gear 4 no longer drives the ratchet 30.
[0070] On the figure 3 In the winding configuration, the winding torque exerted on the ratchet wheel 30 is less than the threshold value, so the connecting springs 9 do not change shape. Thus, the first tooth 12 and the ratchet wheel 30 are driven by the winding train 4.
[0071] On the figure 4When the barrel 2 is fully wound, the winding torque exerted on the ratchet wheel 30 by the winding train 4 exceeds the threshold value, causing the connecting springs 9 to contract or extend depending on their arrangement. In other words, the torque required to rotate the ratchet wheel 30 is too great for the connecting springs 9, which cannot remain in their initial shape.
[0072] In this example, the two connecting springs 9 arranged on the side of the winding gear 4 contract, while the two connecting springs arranged on the other side of the hub 27 extend.
[0073] Consequently, the rim 8 moves away from the winding gear 4, the second tooth 12 of the winding gear 4 no longer having a grip on the first tooth 11, to drive the ratchet 30. The winding gear 4 continues to turn, but the ratchet 30 no longer turns.
[0074] 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.
[0075] The barrel 2 also includes a third peripheral toothed section 18 configured to cooperate with a fourth 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.
[0076] 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.
[0077] 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.
Claims
1. Winding device (1, 10), in particular of a barrel (2) provided with a spring, comprising a ratchet (3, 30) integrally mounted on a rotary winding shaft, the rotary winding shaft being, for example, a winding shaft of the barrel (2), the rotation of which winds the barrel (2), and a winding gear train (4) meshing with the ratchet (3, 30), rotation of the winding gear train (4) causing rotation of the ratchet (3, 30) and that of the rotary winding shaft by application of a torque to the ratchet (3, 30), characterised in that the ratchet (3, 30) is deformable in order to be able to disconnect the ratchet (3, 30) from the winding gear (4).
2. Winding device according to claim 1, characterised in that the ratchet (3, 30) comprises a first peripheral toothing (11) cooperating with a second toothing (12) of the winding gear train (4), when the torque applied to the ratchet (3, 30) is substantially less than a threshold value.
3. Winding device according to claim 2, characterised in that the ratchet (3, 30) deforms when the torque applied to the ratchet (3, 30) substantially exceeds said threshold value, in particular when the barrel (2) is fully wound, such that the first peripheral toothing (11) no longer cooperates with the second toothing (12).
4. Winding device according to claim 3, characterised in that the ratchet (3) comprises a plurality of flexible pawls (15) forming the first teeth (11) of the ratchet (3), the flexible pawls (15) meshing with the second teeth (12) when the torque is less than the threshold value.
5. Winding device according to claim 4, characterised in that the flexible pawls (15) bend when the torque is substantially greater than the threshold value, such that the flexible pawls (15) no longer mesh with the second teeth (12), rotation of the winding gear (4) no longer driving the ratchet (3).
6. Winding device according to any one of claims 4 and 5, characterised in that the ratchet (3) comprises a hub (7) on which the flexible pawls (15) are arranged, the flexible pawls (15) extending around the hub (7).
7. Winding device according to any one of claims 4 to 6, characterised in that each pawl (15) comprises a flexible blade (16) and a tooth (17) arranged at the free end of the flexible blade (16), the teeth (17) of the flexible pawls (15) cooperating with the second toothing (12).
8. Winding device according to any one of claims 4 to 7, characterised in that the flexible pawls (15) are angularly distributed around the ratchet (3).
9. Winding device according to claim 3, characterised in that the ratchet (30) comprises a peripheral rim (8), preferably rigid, provided with the first toothing (11).
10. Winding device according to claim 9, characterised in that the ratchet (30) comprises a hub (27), the peripheral rim (8) being connected to the hub (27) by at least one connecting spring (9), preferably several connecting springs.
11. Winding device according to claim 10, characterised in that the connecting spring(s) (9) contract or stretch when the torque is substantially greater than the threshold value, such that the peripheral rim (8) is moved away from the winding gear train (4), the rotation of the winding gear train (4) no longer driving the ratchet (30).
12. Winding device according to any one of claims 10 and 11, characterised in that the connecting springs (9) are angularly distributed around the hub (27).
13. Winding device according to any one of claims 10 to 12, characterised in that the connecting spring(s) (9) are one or more flexible blades.
14. Winding device according to any one of the preceding claims, characterised in that the ratchet (3, 30) is mounted integrally on the barrel (2), the rotary winding shaft being the winding shaft of the barrel (2) enabling the spring of the barrel (2) to be wound.
15. Horological movement comprising a barrel (2) and a winding device (1, 10) for the barrel (2) according to any one of the preceding claims.