Winding devices and clock movements

Abstract

To provide a winding device for a barrel that reduces friction between coil portions and guarantees a good coiling torque.SOLUTION: A winding device 1 for a barrel 2 includes a ratchet 3 mounted on a rotary winding shaft 5, and a winding gear train 4 meshing with the ratchet 3. The rotation of the rotary winding shaft 5 coils the barrel 2. The rotation of the winding gear train 4 causes the rotation of the ratchet 3 and the rotation of the rotary winding shaft 5 by applying a torque to the ratchet 3. The winding device 1 is provided with disconnection means 10 for disconnecting the ratchet 3 and the rotary winding shaft 5. The disconnection means 10 is arranged on the ratchet 3 and on the rotary winding shaft 5, and is 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, specifically when the barrel 2 is fully coiled.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a winding device, in particular for a watch barrel, which is provided with disconnection means.

[0002] The invention also relates to a clock movement including such a winding device. [Background technology]

[0003] Modern automatic watches typically include an oscillating weight that drives a gear train by gravity. The rotation of this drum allows a leaf or barrel spring that is wound on the drum about an axle to be wound by driving the axle. The rotation is generally forced in only one direction, and a pawl prevents backlash.

[0004] However, when the spring is fully wound, it is important to avoid over-winding which can cause the spring to break or the oscillator to knock. During knocking, the amplitude of vibration increases to a point where the balance wheel abuts against the back of the anchor horn, causing a speed drift due to the balance wheel rebounding against these stops.

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

[0006] This restriction is typically accomplished by sliding the last outer plate of the spring against the inside wall of the drum. When the spring is fully wound around the winding shaft of the barrel, the last wrapped section presses against the outer wall of the drum.

[0007] Therefore, when the winding torque exceeds the friction torque of the last winding section against the wall, it will start to slide. To prevent uncontrolled sliding, the notches allow the ends of the plates to stop sliding as soon as the winding torque drops sufficiently.

[0008] However, the drawback of such a system lies in the sliding friction process of the last winding in the drum: in fact, when the driven mechanism requires high torque, the bearing force and friction of the spring plate against the wall is increased, which leads to wear even in the presence of grease that is expelled from the friction track after a certain time, causing a deterioration in the performance of the barrel.

[0009] Furthermore, in an automatic barrel, conflicting criteria must be met, such as low friction between the winding parts to maximize efficiency, and high friction between the spring and the drum to ensure good winding torque.

[0010] Damage to the drum must also be avoided, such as coating breakage under the pressure of a fully wound spring leaf, sludge buildup, and wall wear. Summary of the Invention

[0011] The object of the present invention is to overcome all or some of the above mentioned drawbacks by providing a winding device equipped with a system for limiting the winding of the spring, replacing the system based on the sliding of a plate against a notch in the inner wall of a drum.

[0012] To this end, the invention relates to a winding device, in particular a winding device for a watch barrel provided with a spring, comprising a ratchet attached to a rotating winding shaft, for example the winding shaft of a barrel, and a winding gear train meshing with the ratchet, the rotating winding shaft being for example the winding shaft of a barrel, the rotation of which winds the barrel, the rotation of the winding gear train exerting a torque on the ratchet thereby causing rotation of the ratchet and therefore of the rotating winding shaft, the winding device being provided with means for disconnecting the ratchet from the rotating winding shaft.

[0013] The present invention is notable in that disconnecting means are arranged on the ratchet and on the rotatable winding shaft and are configured to disconnect the ratchet from the winding shaft when the torque exerted on the ratchet substantially exceeds a threshold value, in particular when the barrel is fully wound.

[0014] That is, if the winding torque is too high, the ratchet hub becomes disconnected from the rotating winding shaft of the barrel and the rotating torque of the ratchet is no longer transmitted to the winding shaft of the barrel, i.e. the ratchet continues to rotate as driven by the winding gear, but the winding shaft no longer rotates.

[0015] The present invention avoids the risk of premature barrel wear, since the limiting device is arranged upstream and outside the barrel, and also avoids the use of conventional take-up limiting devices based on spring friction inside the barrel.

[0016] According to a particular embodiment of the invention, the disconnecting means includes a plurality of flexible pawls and a first set of teeth, the flexible pawls cooperating with the first set of teeth to transmit torque from the ratchet to the rotatable winding shaft to rotate the rotatable winding shaft.

[0017] According to certain embodiments of the present invention, the flexible pawl engages the first set of teeth when the torque falls below a threshold value.

[0018] According to certain embodiments of the invention, the flexible pawl bends when the torque is substantially greater than a threshold value such that the flexible pawl no longer engages the first set of teeth and rotation of the ratchet no longer drives the rotating winding shaft.

[0019] According to a particular embodiment of the invention, a first set of teeth is arranged on the rotatable winding shaft and a flexible pawl is arranged on the ratchet.

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

[0021] According to a particular embodiment of the invention, the rotating winding shaft is arranged to pass through the hub of the ratchet, and a first set of teeth is arranged on the hub around the rotating winding shaft.

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

[0023] According to a particular embodiment of the invention, each pawl comprises a flexible plate and teeth arranged at a free end of said plate, the teeth of the flexible plate cooperating with the first set of teeth.

[0024] According to a particular embodiment of the invention, the ratchet includes a peripheral rim provided with a second peripheral set of teeth cooperating with a third set of teeth of the winding gear train.

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

[0026] According to a particular embodiment of the invention, the rotating winding shaft is a barrel winding shaft allowing the winding of a barrel spring.

[0027] According to a particular embodiment of the invention, each flexible pawl is oriented radially relative to the ratchet and winding shaft.

[0028] The invention also relates to a clock movement including a barrel, which clock movement includes such a barrel winding device. [Brief description of the drawings]

[0029] The objects, advantages and features of the present invention will become apparent from some embodiments thereof, given by way of non-limiting example only with reference to the accompanying drawings, in which:

[0030] [Figure 1] 1A and 1B diagrammatically represent a top view of a winding device according to an embodiment of the invention in an engaged position. [Diagram 2] 2 shows a schematic top view of the winding device according to the invention of FIG. 1 in the disconnected position, in particular when the barrel spring is fully wound up; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] 1 and 2 show an embodiment of a winding device 1 according to the invention, in this case a barrel 2 of a watch.

[0032] The winding device 1 of the barrel 2 includes a ratchet 3 and a winding gear train 4. The winding gear train 4 meshes with the ratchet 3 such that rotation of the winding gear train 4 in a first direction causes the ratchet 3 to rotate in a second direction opposite to the first direction.

[0033] The ratchet 3 is attached to a winding shaft 5, which allows winding of the barrel 2. In this example, the winding shaft 5 is the winding shaft of the barrel 2, and the ratchet is attached to the barrel 2.

[0034] In a variant not shown, the winding shaft is not attached to the barrel and includes a pinion which meshes with a wheel set which drives the winding shaft of the barrel to wind the spring when the ratchet is not attached to the barrel.

[0035] The winding shaft 5 is preferably cylindrical. A first set of teeth 6 is arranged around the winding shaft 5.

[0036] 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 are toric in shape, the radius of the hub 7 being smaller than the radius of the peripheral rim 8. The hub 7 and the peripheral rim 8 are connected by at least one arm, in this case four arms 9, angularly distributed around the hub 7. The hub 7 and the peripheral rim 8 preferably extend in the same plane.

[0037] The hub 7 defines an interior space through which the winding shaft 5 passes at least partially.

[0038] The peripheral rim 8 includes a second outer set of teeth 11 distributed along the peripheral rim 8 around the ratchet 3. The second set of teeth 11 cooperate with a third set of teeth 12 arranged on the winding gear train 4. The winding gear train 4 includes a pinion provided with the third set of teeth 12 arranged on its periphery.

[0039] The barrel 2 contains a spiral spring (not shown in the drawings), referred to as a barrel spring, arranged inside the barrel 2. This spiral spring needs to be wound by either an automatic or a manual winding system.

[0040] To this end, the winding device 1 further comprises a gear train system 13, which is for example driven by the self-winding mass (not shown in the drawings) of a watch movement. The gear train system 13 can also be driven by a winding stem (not shown in the drawings), which in the case of manual winding can be actuated by the crown.

[0041] The wheel set 21 of the gear train system 13 meshes with the third set of teeth 12 of the winding gear train 4. That is, by operating the gear train system 13, a torque is exerted on the ratchet 4, which is transmitted to the winding shaft 5, at least in part, via the winding gear train 4 driven by the wheel set 21 and via the ratchet 3 driven by the winding gear train 4.

[0042] According to the invention, the winding device 1 comprises means 10 for disconnecting the ratchet from the winding shaft. The disconnecting means 10 comprises a first set of teeth 6 arranged around the winding shaft 5, preferably at the same level as the ratchet 3.

[0043] The disconnecting means 10 also includes a number of flexible pawls 15 extending from the hub 7 towards the winding shaft 5. These 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 set of teeth 6 such that rotation of the ratchet 3 causes rotation of the winding shaft 5 as the barrel 2 is wound up.

[0044] Each pawl 15 includes a flexible plate 16 extending from the hub 7 of the ratchet 3. Teeth 17 cooperable with the first set of teeth 6 of the winding shaft 5 are arranged at a free end of each flexible plate 16. During winding, the teeth 17 of the flexible pawl 15 are inserted into the first set of teeth 6 causing the first set of teeth 6 to rotate.

[0045] The disconnecting means 10 comprises at least one flexible claw 15, preferably at least four flexible claws. The number of flexible claws 15 depends on the flexibility of the flexible plate 16 and on the torque threshold value beyond which the disconnecting means 10 is configured to disconnect the ratchet 3 and the winding shaft 5.

[0046] Each flexible pawl 15 is oriented radially with respect to the ratchet 3 and the winding shaft 5. In other words, the flexible pawl 15 is oriented towards the axis of the winding shaft 5.

[0047] In this embodiment, the disconnecting means 10 comprises 16 flexible claws 15 distributed around the winding shaft.

[0048] The flexible blade 16 is configured to bend when a torque threshold normally required to wind the barrel is exceeded, i.e. above the threshold the torque becomes too high and the flexible blade 16 bends, causing the teeth 17 of the flexible pawl 15 to jump into the first set of teeth without being able to drive them, resulting in the winding shaft 5 no longer rotating despite the rotation of the ratchet 3.

[0049] 1 in the winding configuration, the winding torque exerted by the ratchet 3 on the winding shaft is below a threshold value, causing the flexible plate 16 of the flexible pawl 15 to remain substantially straight, i.e. the flexible pawl 15 drives the winding shaft 5 via the first set of teeth 6.

[0050] 2, where the barrel 2 is fully wound, the torque exerted by the ratchet 3 on the winding shaft 5 exceeds a threshold value, causing the flexible plate 16 of the flexible pawl 15 to bend. In other words, the torque required to rotate the winding shaft 5 becomes too great for the flexible pawl to bend. As a result, the teeth 17 of the flexible pawl 15 no longer have sufficient grip of the first set of teeth 6 to drive the winding shaft 5.

[0051] These disconnecting means protect the barrel 2 from over-winding and prevent premature wear on the inside of the barrel 2.

[0052] The barrel 2 further includes a fourth circumferential set of teeth 18 configured to cooperate with a fifth set of teeth 19 of a wheel set 20 of the clock movement. The wheel set 20 may be, for example, a center or average wheel, or a striking wheel set. Once wound, the barrel 2 provides the energy required to operate the clock movement via the wheel set 20.

[0053] The invention also relates to a clock movement, not shown in the drawings, which movement includes a barrel and a barrel winding device as described above.

[0054] Naturally, the invention is not limited to the embodiments described with reference to the drawings, and variants are conceivable without departing from the scope of the invention.

[0055] For example, in the embodiment shown in FIGS. 1 and 2, a flexible pawl 15 is arranged on the ratchet 3 and a first set of teeth 6 is arranged on the winding shaft 5 .

[0056] However, in other embodiments not shown, the flexible pawl can be disposed on the winding shaft and the first set of teeth can be arranged on the inside of the ratchet hub, with the flexible plate of the flexible pawl extending from the winding shaft towards the ratchet hub to cooperate with the first set of teeth.

[0057] That is, as long as the torque exerted on the flexible pawl is below a threshold value, the ratchet drives the winding shaft, and when the torque exerted on the flexible pawl exceeds the threshold value, the flexible plate bends and no longer engages the first set of teeth, and the ratchet rotates without driving the winding shaft.

Claims

1. A winding device (1) for a barrel (2) provided with a spring, comprising: The winding gear set includes a ratchet (3) attached to a rotating winding shaft (5) and a winding gear train (4) meshing with the ratchet (3), the rotating winding shaft (5) is the winding shaft of the barrel (2) and its rotation winds up the barrel (2), the rotation of the winding gear train (4) exerts a torque on the ratchet (3) thereby causing the rotation of the ratchet (3) and thus the rotation of the rotating winding shaft (5), the winding device (1) being provided with a means (10) for disconnecting the ratchet (3) from the rotating winding shaft (5), said disconnecting means (10) being arranged on said ratchet (3) and on said rotatable winding shaft (5) and configured to disconnect said ratchet (3) from said rotatable winding shaft (5) when a torque exerted on said ratchet (3) exceeds a threshold value; A winding device, wherein said disconnecting means (10) comprises a plurality of radially extending flexible claws (15) and a first set of teeth (6) arranged around said rotatable winding shaft (5).

2. A winding device as described in claim 1, characterized in that the flexible pawl (15) cooperates with the first set of teeth (6) to transmit the torque of the ratchet (3) to the rotating winding shaft (5) to rotate the rotating winding shaft (5).

3. 3. A hoisting device according to claim 2, characterized in that the flexible pawl (15) engages the first set of teeth (6) when the torque falls below a threshold value.

4. 3. A winding device according to claim 2, characterized in that the flexible pawl (15) bends when the torque is substantially greater than the threshold value, such that the flexible pawl (15) no longer engages with the first set of teeth (6) and rotation of the ratchet (3) no longer drives the rotating winding shaft (5).

5. A winding device as described in claim 2, characterized in that the flexible claw (15) is arranged on the ratchet (3).

6. 6. A hoisting device according to claim 5, characterized in that the ratchet (3) comprises a hub (7) on which the flexible pawls (15) are arranged, the flexible pawls (15) extending towards the rotating hoisting shaft (5).

7. 7. A winding device according to claim 6, characterized in that the rotating winding shaft (5) is arranged to pass through the hub (7) of the ratchet (3) and the first set of teeth (6) are arranged around the rotating winding shaft (5) at the hub (7).

8. 3. A winding device according to claim 2, characterized in that the flexible claws (15) are angularly distributed around the rotating winding shaft (5).

9. A winding device as described in claim 2, characterized in that each of the flexible claws (15) includes a flexible plate (16) and teeth (17) arranged on the free end of the flexible plate (16), and the teeth (17) of the flexible claws (15) cooperate with the first set of teeth (6).

10. 2. A hoisting device according to claim 1, characterized in that the ratchet (3) comprises a peripheral rim (8) provided with a second set of teeth (11) cooperating with a third set of teeth (12) of the hoisting gear train (4).

11. A hoisting device according to claim 1, characterized in that the ratchet (3) is attached to the barrel (2).

12. 2. A winding device according to claim 1, characterized in that the rotating winding shaft (5) is the winding shaft of the barrel (2) allowing the winding of the barrel (2) spring.

13. A clock movement comprising a barrel (2) and a winding device (1) according to claim 1.

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