CH713407B1 - Winding system for a timepiece. - Google Patents

Abstract

The invention relates to a winding system arranged for winding a mainspring of a timepiece, said winding system comprising a ratchet system ratchet system comprising a first mobile (10) and a second mobile (14) mounted coaxially for rotation with respect to each other, the first mobile (10) and the second mobile (14) being one fixed to a hub and the other fixed to a wheel ( 16), one of the first mobile (10) and the second mobile (14) being intended to be driven by a winding member, the other of the first mobile (10) and the second mobile (14) being intended in winding said mainspring, in which one of the first mobile (10) and the second mobile (14) comprises unidirectional drive teeth (32), and the other of the first mobile (10) and the second mobile (14) comprises a pawl (40) associated with a spring (42). According to a first aspect of the invention, the spring (42) and the pawl (40) form a rigid connection between the first mobile (10) and the second mobile (14) in a latching state, and an elastic connection between the first mobile (10) and the second mobile (14) in an unlatched state. According to a second aspect of the invention, the pawl (40), the spring (42) and that of the first mobile (10) and of the second mobile (14) which comprises the pawl, are monolithic. The invention also relates to a barrel system comprising such a winding system.

Description

Technical area

The present invention relates to the field of watchmaking, it relates, more particularly, to a winding system for a timepiece comprising a particular ratchet system. The latter comprises a first mobile and a second mobile mounted coaxially rotatably with respect to each other. The first mobile and the second mobile being one secured to a hub and the other secured to a wheel.

[0002] Such snap-fastening systems are commonly used in watchmaking, to produce one-way drive systems, clutches or torque-limiting drive systems in the context of a kinematic winding chain. a mainspring.

[0003] In known systems, one of the first mobile and the second mobile comprises unidirectional drive teeth, and the other of the first mobile and the second mobile comprises a pawl associated with a spring. The pawl is arranged to cooperate with the unidirectional drive toothing to integrally connect in rotation the first mobile and the second mobile when they pivot in a first direction of rotation, defining a latching state, and to leave the first mobile with respect to the second mobile when they pivot relative to each other in a second direction of rotation, defining an unlatched state.

[0004] Depending on the configuration, the wheel or the hub can be a motor, that is to say be driven by a winding stem or an oscillating weight, in order to drive the other mobile in a single direction.

State of the art

[0005] In the state of the art, various alternative constructions are known for producing such a mechanism. In general, it is extremely difficult to obtain a system which makes it possible both to transmit high torques, without having springs which are strong and which, as a result, induce high friction during disengagement. This friction generates wear, parasitic noise, and depending on the application of the system, a loss of efficiency.

[0006] For this purpose, patent CH 705322 proposes the use of pawls, integral with their respective springs, being housed in an appropriate opening of the wheel and cooperating with external toothing formed on the hub. Each pawl has several teeth, cooperating with the corresponding toothing of the hub, which makes it possible to generate significant friction and therefore to transmit a high torque. When unclipping, only one of the pawl teeth is in contact with the teeth, which reduces friction when unclipping. However, this solution requires maintaining the pawls in their housing by flanges on either side of the hub. In addition, the springs of the pawls are stressed both during latching and during unlatching and it remains difficult to dissociate the adjustment from the forces involved in the two directions of rotation. This document explicitly mentions the use of such a drive system in the context of winding a barrel spring by means of an articulation hinge of a portable electronic device.

[0007] Patent DE 1922475U also proposes a construction in which the wheel of the drive system is secured to the pawl by means of an elastic blade. As before, this solution implies that the force transmissible between the hub and the wheel depends on the characteristics of the elastic blade. The same is true for unclipping.

[0008] In general, there is a significant correlation between the transmissible forces and the detent forces. Such a result cannot in particular be suitable for an automatic winding mechanism driven by an oscillating weight, since the energy losses and the resistance to declicking imply too low a yield.

The object of the present invention is to provide a winding system provided with a snap-fastening system free from the above drawbacks and making it possible to dissociate the transmissible forces and the declicking forces, thus improving the performance of the winding system. . It is thus possible to obtain a capacity to transmit high torques in the winding system, while limiting the forces and other losses of energy during declicking.

Disclosure of Invention

More specifically, the invention relates to a winding system arranged for winding a mainspring of a timepiece. This winding system comprises a latching system comprising a first mobile and a second mobile mounted coaxially rotatably with respect to each other, the first mobile and the second mobile being one fixed to a hub and the the other secured to a wheel, one of the first mobile and the second mobile being intended to be driven by a winding member such as a winding stem, an oscillating weight or the like, the other from the first mobile and the second mobile being intended to wind up said mainspring while being in kinematic connection with the latter, in which one of the first mobile and the second mobile comprises unidirectional drive teeth, and the other of the first mobile and the second mobile comprises a pawl associated with a spring, the pawl being arranged to cooperate with the unidirectional drive toothing to integrally connect in rotation the first mobile and the second mobile when they pivot in a first direction of rotation, defining a latching state, and to leave the first mobile with respect to the second mobile when they pivot relative to each other in a second direction of rotation, defining an unlatched state.

According to a first aspect of the invention, the latching system is arranged so that the spring and the pawl form a rigid connection between the first mobile and the second mobile in the latching state, and an elastic connection between the first mobile and the second mobile in the unlatching state, the spring not being stressed in the latching state.

Brief description of the drawings

Other details of the invention will appear more clearly on reading the description which follows, made with reference to the appended drawing in which: Figure 1 and Figure 2 are respectively top views in perspective, and in section, of a ratchet system suitable for a winding system according to the invention, Figures 3, 4 and 5 show different variants of spring 42 and pawl that can be implemented in such a ratchet system, and FIGS. 6 and 7 illustrate the integration of such a snap-fastening system in a barrel.

Embodiment of the invention

There is shown in Figures 1 to 5 an embodiment of a snap system adapted to a winding system according to the invention. This system is intended to take place in a kinematic winding chain which kinematically connects a winding device, such as a winding stem, an oscillating mass or the like, to a mainspring in order to be able to wind the latter under the effect of the winding device. The ratchet system can in principle be located anywhere in such a kinematic chain, but can in particular be integrated into a barrel system housing said mainspring, as will be described below in the context of Figures 6 and 7.

In this embodiment, there is a first mobile 10 secured to a hub 12, and a second mobile 14 secured to (or comprising) a wheel 16. The first mobile 10 and the second mobile 14 are mounted coaxially, rotatable relative to each other. Those skilled in the art will have no difficulty in adapting the present description to an embodiment in which the construction would be reversed, that is to say in which the first mobile 10 would be integral with a wheel 16 and the second mobile 14 secured to a hub 12. One of the first mobile 10 and the second mobile 14 can be configured as an input of the ratchet device, intended to be driven in rotation by a winding member such as a crown arranged to be operated manually or an oscillating weight. The other can be configured as an output, and is therefore intended to wind a mainspring, such as for example a spring housed in a barrel. A person skilled in the art knows how to provide kinematic connections upstream and downstream of the snap-fastening device in order to link the latter on the one hand with the winding member, on the other hand with the mainspring. Consequently, these kinematic connections as well as the winding members should not be described in detail here.

[0015] More particularly, in this embodiment, the first mobile 10 comprises a central opening 18. The hub 12 comprises a plate 20 which comprises concentric portions of different heights. The board 20 thus defines a flat span 22 at its periphery, the role of which will appear later. The board 20 further comprises a central body 24, forming a circular bearing 26 at the interface between the body and the flat bearing 22. Finally, in the center of the board 20, an axis 28 allows the rotational mounting of the hub 12, the ends of the pin 28 projecting on either side of the plane of the board 20.

Through its central opening 18, the first mobile 10 is mounted without play on the axis 28 of the hub 12, on the side of the flat surface 22. The first mobile 10 is also fixed on the hub 12. Different means of fixing are possible, such as driving on the axis, gluing or other. In the example, the first mobile 10 is screwed onto the body of the board 20. The wheel 16 is guided in rotation on the circular bearing surface 26 and is positioned in height between the flat bearing surface 22 that the hub 12 comprises, and the first mobile 10. The wheel 16 comprises a circular groove 30 whose outer diameter is larger than the diameter of the first mobile 10. The internal diameter of the groove 30 can be substantially equal to the diameter of the first mobile 10. The second mobile 14 is arranged in the groove 30, integrally with the wheel 16. The second mobile 14 takes the form of a crown, provided with an internal toothing 32 located at least partially in the plane of the first mobile 10. The internal toothing 32 is of the toothing type 32 unidirectional drive, such as a wolf tooth toothing for example. This type of toothing 32 is generally asymmetrical and is provided to allow drive in one direction and de-gearing in the other direction of rotation, as will be better understood below.

The first mobile 10 comprises a pawl 40 associated with a spring 42, the pawl 40 being arranged to cooperate with the toothing 32 unidirectional drive. More particularly, the pawl 40 is mounted on the mobile. It comprises a spout 44 arranged to cooperate with the toothing 32 of unidirectional drive, the spout 44 being shaped so as to link the first wheel set 10 and the second wheel set 14 together in rotation when they pivot in a first direction of rotation.

Referring to Figure 1, if the first mobile 10 is driven by the hub 12 in the counterclockwise direction, it drives the second mobile 14. This defines a latching state. This is also defined by a motor drive of the second mobile 14 in the clockwise direction, which also makes it possible to drive the first mobile 10 in rotation. The spout 44 is also arranged so as to allow the first mobile 10 to rotate freely with respect to the second mobile 14 when they pivot relative to each other in a second direction of rotation. Referring to Figure 1, if the first mobile 10 is driven by the hub 12 in the direction of clockwise, it rotates without driving the second mobile 14, the pawl 40 moving by constraining the spring 42. We define thus a state of disengagement. This is also defined during a motor drive of the second mobile 14 in the counter-clockwise direction, which is also carried out without driving the first mobile 10 in rotation.

Advantageously, the first mobile 10, the pawl 40 and the spring 42 are monolithic and come from one piece. They can be made monolithically, by DRIE-type etching techniques, or LIGA-type growth techniques. Thus, the first mobile 10, the pawl 40 and the spring 42 are arranged in the same plane, this plane being at least partially located in the plane of the toothing 32 for unidirectional drive of the second mobile 14, to allow the cooperation of the spout 44 of the pawl 40 with this toothing 32. By multilevel manufacturing techniques, the spring 42 and the pawl 40 can have different thicknesses, making it possible, for example, to have good mechanical strength for the pawl 40 and a low stiffness coefficient for the spring 42, by making a pawl 40 thicker than the spring 42. A very advantageous construction is thus obtained, easy to assemble and compact, requiring no plate to hold the pawl or the spring in its teeth.

In the preferred embodiment, proposed as an illustrative example of the invention, the first mobile 10 has a lateral cutout 46, comprising an arcuate opening 48 opening laterally opposite the toothing 32 unidirectional drive. The pawl 40 has a circular base 50 with a diameter slightly smaller than the diameter of the circular opening 48. The base 50 is housed in the circular opening 48 which forms a seat for the base 50 of the pawl 40, which is capable of pivoting in reference to the center of the seat, but also to lean against the walls of the seat. The wall of the circular opening 48 is thus arranged to form an abutment of the base of the pawl 40.

The spring 42 is arranged to exert on the pawl 40 a force which tends to keep it engaged in the toothing 32 of unidirectional drive, by exerting a torque tending to put the base of the pawl 40 in rotation in the opening.

The spring 42 is advantageously of the blade type, formed directly in the thickness of the first mobile 10. It connects the first mobile 10 and the pawl 40, extending into the space left free by the lateral cutout. It is attached to the pawl 40 by the edge of the arm formed between the base 50 and the beak 44. Thus, a rotation of the pawl 40 with reference to the center of the circular opening 48, causes an elastic deformation of the spring 42.

According to the invention, the latching system is arranged so that the spring 42 and the pawl 40 form a rigid connection between the first mobile 10 and the second mobile 14 in the latching state, and an elastic connection between the first mobile 10 and the second mobile 14 in the unlatched state.

[0024] By rigid connection, we mean an essentially rigid, or even exclusively rigid, connection, that is to say which only solicits very little, if at all, the spring 42 of the pawl 40. By elastic connection, we mean a connection which causes the elastic deformation of the spring member 42.

More specifically, the pawl 40 is arranged so that the moment of force exerted on the pawl 40 around its axis of rotation, by the action of the toothing 32 of unidirectional drive, when it is in the latching state, is zero or substantially zero. To do this, the person skilled in the art can act on the geometries of the pawls of the pawl 40 and of the toothing 32 of unidirectional drive, as well as on their respective positioning.

The pawl 40 is further arranged so that, in the latching state, the force exerted by the toothing 32 of unidirectional drive on the pawl 40 or the resultant of these forces, has an orientation essentially , preferably exclusively radial tending to press the base of the pawl 40 against the wall of the seat, without putting the pawl 40 in rotation. In this case, with reference to Figure 2, the support of a first tooth of the toothing 32 of unidirectional drive on the flank 44a of the beak 44 causes a counter-support of the flank 44b on the neighboring tooth. The resultant of these forces passes through the axis of rotation of the pawl and the torque it exerts is zero.

[0027] Thus, given that the latching system is arranged to avoid, in any case minimize, the rotation of the pawl 40 when it is in the latching state, the deformation of the spring 42 is also minimized.

We can provide different forms of spring 42 to obtain the same orientations of the elastic forces. Figures 3, 4 and 5 show different examples.

In Figure 3, as in Figures 1 and 2, the spring 42 forms a bend from the edge of the side cutout 46, then forms several meanders before joining the edge of the pawl arm 40.

In Figure 4, the side cutout extends beyond the level of the circular opening 48, forming a slot 52 in the first mobile. The spring 42 is connected by one of its ends, with this slot, before joining the edge of the pawl arm 40, by several meanders, similar to those of figure 3.

In Figure 5, the side cutout opens a strip 54 between the center of the first mobile and its periphery which includes the circular opening 48. The spring 42 is connected by one of its ends with the end of the strip. It forms a single bend before connecting with the ratchet, at the base of spout 44.

[0032] Thus and in a particularly advantageous manner, the spring 42 is not stressed during the latching phases. The drive of the driven mobile by the leading mobile is done with very little play, the minimum play between the base of the pawl 40 and its seat. This drive is done by a rigid connection, which also allows high torques to be transmitted. Above all, given that the spring 42 does not intervene in this phase, it can be sized freely for the unlatching phases and be very light, thus limiting the stresses during the passage of the pawl 40. One can perfectly dissociate the sizing and the adjustment of the elements involved during engagement and disengagement.

If the mainly illustrated embodiment proposes to have the first mobile 10 which carries the pawl 40, as mentioned above, the person skilled in the art can consider different combinations. For example, the pawl 40 could be placed on the mobile which is integral with the wheel 16, in this case the second mobile 14. The toothing 32 for unidirectional drive is then arranged on the mobile integral with the hub 12, in the species the first mobile 10.

In both cases, it is possible to have unidirectional drive teeth 32 which are internal or external teeth 32, even if certain configurations can be complex.

[0035] In all the configurations, one or the other of the mobiles can be the driving mobile, that is to say receiving the torque to be transmitted, the other of the mobiles being the driven mobile, during the phases of click. In addition, the ratchet system may comprise a plurality of spring-pawl assemblies which are distributed angularly around the axis 28. In this case, the pawls 40, the springs 42 and the first or the second mobile are all monolithic and came in one piece.

[0036] Thus, a particularly effective ratchet system is proposed, both in terms of its size, the torque that it is capable of transmitting, and the dissociation of the ratcheting and unlatching functions, which make it possible to size the spring member 42 only considering the detent. The wear and friction stresses during unclipping are thus reduced compared to the devices of the prior art.

[0037] Figures 6 and 7 illustrate in isometric view as well as in diametral section along the axis AA, a barrel system 60 incorporating a latching system of the type described above, in particular that illustrated in Figures 1 and 2.

The barrel 60 comprises a drum 61 provided with a first external toothing 62 intended to drive a watch movement (not shown). Inside the drum 61 is housed a mainspring 63, the outer end of which is linked to the drum 61, and the inner end of which is linked to the barrel arbor 64 via a plug.

The shaft 64 is free to pivot relative to the drum, and carries, on a first face of the drum 61, a latching system as described above. In the variant illustrated, the first mobile 10 of the ratchet system is integral in rotation with a square 64a (or other suitable shape) that comprises the shaft 64, this square 64a taking place in the central opening 18 of the first mobile 10. This central opening 18 is of complementary shape to the square 64a in order to make these two elements mutually integral in rotation.

The first mobile 10 comprises two pawls 40, diametrically opposed to each other, each being similar to that of Figures 1 and 2, but they can be substituted by those of the other figures mentioned above. Therefore, these pawls 40 need not be described in detail again.

The second mobile 14, carrier of the toothing 32, is again arranged in a groove 30 with which the wheel 16 is provided. The diameter of the latter is identical to that of the toothing 62 of the drum 61, but other diameters are possible.

[0042] The second wheel 16 acts as an input, and is intended to be driven by a winding device (not shown) such as a winding stem or an oscillating weight, via a cog and/or an ad hoc conversion mechanism as generally known to those skilled in the art.

When the second wheel is pivoted clockwise (relative to Figure 6) by the winding member, the pawls 40 are driven by the toothing 32, and this rotation is transmitted to the shaft 64. The mainspring 63 is thus reassembled. On the other hand, when the second wheel 16 rotates in the opposite direction, the pawls 40 rise as described above, disengage from the toothing 32 and the shaft 64 is not driven in rotation.

[0044] It goes without saying that other configurations of snap-fastening systems as defined above can be used for the same purpose.

It is also noted that the barrel 60 illustrated in Figures 6 and 7 further comprises a second output, in particular an additional wheel 65 located on the other side of the drum 61 than that where the ratchet system is located. . This additional wheel can drive an input of a power reserve system, or can drive an additional device such as a striking device independently of the drum 61 of the barrel 60 as well as of the movement finishing gear train (not shown) .

[0046] Those skilled in the art may also consider other alternatives from the description given above by way of non-limiting illustration of the invention, the scope of the protection being delimited by the claims. In particular, the ratchet system can also be used as an automatic reverser, that is to say to convert the rotations of the oscillating weight in both directions, into a unidirectional rotation of the barrel ratchet. Different types of inverters with ratchet systems working in opposition are known to those skilled in the art. The one described above allows a clear improvement in efficiency, because the springs can be dimensioned slightly in their detent component. It will therefore be possible to adapt one or more snap-fastening systems as proposed above, in an automatic reverser.

[0047] In the examples given above, the ratchet system being kinematically in the kinematic chain extending between the winding member and the shaft 64 of the barrel 60, it is obviously part of the winding device arranged to wind the spring 63.

Claims (14)

1. Winding system arranged for winding a mainspring (63) of a timepiece, said winding system comprising a latching system comprising a first mobile (10) and a second mobile (14) mounted coaxially rotatable with respect to each other, the first mobile (10) and the second mobile (14) being one fixed to a hub (12) and the other fixed to a wheel (16) , one of the first mobile (10) and the second mobile (14) being intended to be driven by a winding member, the other of the first mobile (10) and the second mobile (14) being intended to wind said mainspring (63), in which one of the first mobile (10) and the second mobile (14) comprises unidirectional drive teeth (32), and the other of the first mobile (10) and the second mobile (14) comprises a pawl (40) associated with a spring (42), the pawl (40) being arranged to cooperate with the drive toothing (32) unidirectional for integrally rotating the first mobile (10) and the second mobile (14) when they pivot in a first direction of rotation, defining a latching state, and for leaving the first mobile (10) free to rotate by relative to the second mobile (14) when they pivot relative to each other in a second direction of rotation, defining a detent state, characterized in that it is arranged so that the spring (42) and the pawl (40) form a rigid connection between the first mobile (10) and the second mobile (14) in the latching state, and an elastic connection between the first mobile (10) and the second mobile (14) in the unlatching state, the spring (42) not being stressed in the latching state. 2. Winding system according to claim 1, characterized in that the pawl (40) is pivotally mounted on its mobile along an axis of rotation and in that the pawl (40) is arranged so that the moment of force exerted on the pawl (40) along its axis of rotation, by the action of the other mobile when it is in the latching state, is zero or substantially zero. 3. Winding system according to one of the preceding claims, characterized in that the mobile comprising the pawl (40), said pawl (40) and said spring (42) are monolithic. 4. Winding system according to one of the preceding claims, characterized in that the mobile comprising the pawl (40), said pawl (40) and said spring (42) are arranged in the same plane. 5. Winding system according to claim 4, characterized in that the mobile comprising the pawl (40) has a circular opening opening out laterally, the pawl (40) having a circular base of diameter less than the diameter of said opening, said base being housed in said opening, and in that the wall of the opening forms an abutment of the base in the latching state. 6. Winding system according to one of the preceding claims, characterized in that the mobile comprising the pawl (40) is that of the first and second mobiles (10, 14) which is integral with a hub (12), and in that the mobile comprising the toothing (32) for unidirectional drive is that of the first and second mobiles (10, 14) which is secured to the wheel (16). 7. Winding system according to one of claims 1 to 5, characterized in that the mobile comprising the pawl (40) is that of the first and second mobile (10, 14) which is integral with the wheel (16), and in that the mobile comprising the toothing (32) for unidirectional drive is that of the first and second mobiles (10, 14) which is integral with the hub (12). 8. Winding system according to one of Claims 6 and 7, characterized in that the toothing (32) for unidirectional drive is an internal toothing (32). 9. Winding system according to one of Claims 6 and 7, characterized in that the toothing (32) for unidirectional drive is an external toothing (32). 10. Winding system according to claims 6 and 8, characterized in that the wheel (16) is guided in rotation on a circular surface (26) which the hub (12) comprises and positioned in height between a flat surface (22) that includes the hub (12), and the mobile comprising the pawl (40). 11. Barrel system (60) comprising a winding system according to one of claims 1 to 10, wherein said snap-fastening system is mounted on a barrel (60) comprising a drum (61) housing said mainspring (63 ) as well as a barrel shaft (64) to which an inner end of said mainspring (63) is attached. 12. Barrel system (60) according to the preceding claim, wherein said ratchet system is carried by said barrel shaft (64). 13. Barrel system (60) according to the preceding claim, wherein said first mobile (10) is integral in rotation with said barrel shaft (64), said second mobile (14) being intended to be driven by said winding member. 14. Barrel system (60) according to the preceding claim, wherein said second mobile (14) comprises said unidirectional drive toothing (32).