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EP-4375757-B1 - WINDING DEVICE OF A TIMEPIECE BARREL, PROVIDED WITH DISENGAGING MEANS

EP4375757B1EP 4375757 B1EP4375757 B1EP 4375757B1EP-4375757-B1

Inventors

  • CUSIN, PIERRE
  • Jeanneret, Laurent

Dates

Publication Date
20260513
Application Date
20221124

Claims (10)

  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.

Description

Technical field of the invention The invention relates to a winding device, in particular for a watch barrel, equipped with disengagement means. The invention also relates to a clockwork movement comprising such a winding device. Technological background Most modern self-winding mechanical watches generally feature an oscillating weight that drives a gear train by gravity. The rotation of the drum winds a mainspring, the barrel spring, which is wound around a drum on a central axis. This winding action drives the axis. The rotation is usually forced in only one direction and is prevented from reversing by a pawl. 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. To avoid these risks, such cylinders generally have a system for limiting the winding of the cylinder spring. 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. 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. 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. 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. It is still necessary to prevent damage to the drum, such as the coating tearing, the formation of sludge, and wear on the walls under the pressure of the fully wound spring. Some documents have already attempted to address this problem, such as the following documents: EP3220206A1 or FR1354488A . Summary of the invention 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. 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 to the ratchet, the winding device being equipped with means for disengaging the ratchet and the rotating winding shaft. 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. 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. 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. 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. According to the invention, the flexible pawls engage with the first toothing when the torque is less than the threshold value. 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 engage with the first toothing, the rotation of the ratchet no longer dr