EP1738229B1 - Crown for timepiece, comprising a disengaging device - Google Patents

Abstract

The crown (1) has two springs (4), deformable in elastic manner, cooperating in rotation around an axis (X1), in a rotational direction, with a rigid ring (15). The springs are integrated with an hour wheel (11) without depending on value of turning torque while the ring is fixed with respect to the crown. Each spring has a central base (5) from which arms (6) extend, and the ring has steps (16) disposed opposite to the arms. An independent claim is also included for a timepiece comprising a crown.

Description

TECHNICAL AREA

The present invention relates to a crown for a timepiece comprising a housing X1 axis inside which are in particular arranged a gun having, in the region of a first end, means for fixing a winding stem. The housing also comprises at least one first member, elastically deformable, cooperating by friction in a rotational movement relative to the axis X1, at least in a first direction of rotation, with a rigid element of suitable shape, as long as the torque transmitted by one of these elements to the other remains below a predefined value. Beyond the predefined value, the first deformable element is capable of deforming to involve a sliding connection between it and the rigid element.

TECHNOLOGICAL BACKGROUND

Such crowns of the type comprising a disengaging device are known from the prior art. Such devices used are known, for example, to avoid damaging the mechanism of a timepiece when the winding stem is driven by the user to arm the barrel spring, the latter being fully armed.

The patent US 2,637,987 describes several embodiments of a crown of the type mentioned above. All the embodiments described provide that the ring has a cylindrical housing inside which the disengaging device is arranged. In particular, the housing comprises, at its periphery, a leaf spring integral with the crown and intended to cooperate with one end of the winding stem disposed within the housing. For this purpose, the end of the winding stem has a particular form, specific to each of the embodiments described, adapted to the shape of the corresponding leaf spring.

The cooperation between the leaf spring and the winding stem is effective as long as the torque to be transmitted to the winding stem from a rotation of the crown, via the leaf spring, does not exceed a predefined value. When this preset value is reached, which may be the case for example when the barrel spring is fully armed, the leaf spring deforms and stops cooperation with the winding stem. Thus, any subsequent rotational movement of the crown under these conditions is no longer transmitted to the winding stem.

The device described in this US patent however has a number of disadvantages. Indeed, the structure described and shown is complex both from the point of view of manufacture and assembly, particularly because of the dimensions to be considered in the field of crowns for watchmaking. The manufacture of different springs involved is delicate, on the one hand, because of their shape and, secondly, because they are mounted prestressed, which makes their mounting in the delicate crown.

Another disadvantage of the device described in the patent US 2,637,987 is derived from the need to provide a particular shape for the end of the winding stem disposed within the crown, so that it can cooperate with the particular shape retained for the spring. Such a constraint requires the manufacturer to provide different manufacturing processes for the different forms of winding stem to use, thus representing a source of additional cost.

Another document disclosing a similar device is the patent US 2,716,875 .

SUMMARY OF THE INVENTION

The main object of the present invention is therefore to overcome the above-mentioned drawbacks of the prior art by providing a device for a crown, making it possible to avoid damaging the movement of a timepiece, this device having a simple structure and allowing easy assembly compared to the devices of the prior art.

For this purpose, the present invention relates to a ring of the type mentioned above, defined by the subject of claim 1.

Thanks to the features of this claim, the device according to the invention has a relatively simple structure obtained by a simple assembly. In addition, the fact that the elastic element is disposed on the barrel receiving the winding stem does not require the manufacturer of particular structure of the end of the winding stem disposed in the ring. Such a feature allows the manufacturer to be limited to a single winding stem structure, regardless of the embodiment of the present invention implemented.

In a preferred embodiment of the present invention, the deformable member is in the form of a spring having a central base from which extend at least two deformable arms, preferably four. In this case, the rigid element is made in the form of a ring having a plurality of notches arranged on its inner periphery and intended to cooperate with surface regions of the deformable arms.

Thanks to such a structure, the deformable element can be mounted in the housing of the ring without being prestressed, which greatly simplifies the assembly relative to the device of the aforementioned prior art.

In a nonlimiting preferred manner, the cooperation between the spring and the ring is permanent in a first direction of rotation, that is to say that it does not depend on the value of the torque transmitted by one of the elements to the other, while a declutching threshold is provided in the second direction of rotation.

Alternatively, there are two stages each of which comprises a spring and notched ring assembly, each of the two stages being intended to allow disengagement of the device in a predefined direction. In this case, the ring is able to be moved along its axis X1 relative to the winding stem to activate one stage or the other.

Preferably, the deformable element and the rigid element are respectively made of materials whose respective hardnesses are close, such a characteristic to ensure a good life of the device according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1 représente une vue en perspective éclatée de la couronne pour pièce d'horlogerie selon un mode préféré de la présente invention;
• la figure 2 représente une vue en coupe transversale de la couronne représentée sur la figure 1 lorsque ces composants sont assemblés, et
• la figure 3 représente une vue en perspective montrant en détail la nature de la coopération mise en oeuvre entre les éléments déformable et rigide.

Other features and advantages of the present invention will appear more clearly on reading the detailed description which follows, made with reference to the accompanying drawings given by way of non-limiting example and in which:

• the figure 1 is an exploded perspective view of the timepiece crown according to a preferred embodiment of the present invention;
• the figure 2 represents a cross-sectional view of the crown shown in FIG. figure 1 when these components are assembled, and
• the figure 3 represents a perspective view showing in detail the nature of the cooperation implemented between the deformable and rigid elements.

DETAILED DESCRIPTION

The figure 1 is an exploded perspective view of the crown according to a preferred embodiment of the present invention to highlight the simplicity of the corresponding structure and the simplicity of mounting the various components with each other.

The various constituent elements of the crown according to the invention are represented in an order schematizing the sequences of their assembly on the figure 1 .

The reference numeral 1 designates the crown as such, the latter having a rotation symmetry axis X1 and being hollow so as to define a housing (visible on the figure 2 ) to arrange the following constituents. A hollow support element 2 whose dimensions are adjusted to the dimensions of the housing of the ring is in the form of a cylinder, closed on one side for illustrative purposes, by a bottom 3. There are then two identical springs 4 for be arranged close to the bottom 3 of the support element 2. Here two identical springs 4 are provided because of the thickness of material necessary to obtain the desired rigidity for the purpose of simplifying the machining process of the machine. these springs.

Each of the springs 4 is of the flat spring type comprising a central base 5, of general shape close to the shape of a square, from which extend four elastically deformable arms 6. Each of the arms 6 comprises two successive portions, a first short portion 7 extending from the central base 5 in a substantially radial direction before presenting a bend 8, substantially at right angles, extended by a second portion 9, substantially rectilinear . It is further noted that the central base 5 of each of the springs 4 has a hole 10 centered with respect to the axis X1 and of substantially square shape in the example shown. The operation of the springs 4 will be explained in more detail in connection with the figure 3 .

Then we find, on the figure 1 , a barrel 11 for receiving an end of a winding stem (not shown). The barrel 11 has a main portion 12 of cylindrical shape, surmounted by a disc-shaped head 13 of diameter greater than the diameter of the main part. The head 13 is itself surmounted by a portion 14 of smaller transverse dimensions than those of the head, arranged projecting with respect to the latter and centered on the axis X1. The projecting portion 14 has a contour of complementary shape, here substantially square, to that of the holes 10 of the springs and intended to cooperate therewith. Any other non-circular shape may be provided for the opening 10 and the protruding portion 14, for example polygonal, without departing from the scope of the present invention as long as a drive in rotation of the projecting portion 14 by the springs 4 is possible because of their cooperation. Thus, as is more clearly apparent from the figure 2 , the height of the projecting portion 14 is greater than the thickness of the two springs 4 together.

Next, there is provided a rigid element 15 in the form of a ring or washer, the central opening of which has a diameter greater than the diameter of the head 13 of the barrel, as well as a periphery having notches 16. The ring 15 is intended to to be positioned near the bottom 3 of the support member so that the notches 16 are located opposite the arms 6 of the springs 4, as is more apparent from the figure 3 .

An additional washer 17 then comes to support the ring 15 and the barrel 11. For this purpose, the washer 17 has an outer diameter substantially equal to the diameter of the ring 15 and a central opening 18 of diameter less than the diameter of the head 13 of the barrel. The washer 17 further comprises an annular shoulder 19 of internal diameter greater than the diameter of the head 13 of the barrel and of external diameter substantially equal to the diameter of the ring 15. The washer 17 is made so that the thickness of its shoulder annular 19 is equal to or greater than the thickness of the head 13 of the barrel, the shoulder thus providing the function of a spacer.

The remaining constituents are closing elements of the device to seal them without making any other contribution to the disengaging device according to the present invention.

For this purpose, it is intended to use a reduction ring 20 whose outer diameter is substantially smaller than the inner diameter of the support member 2 and against which is disposed an annular ring 21 of the O-ring diameter type at rest. substantially greater than the inner diameter of the support member 2. A flat washer 22 is then provided to close the housing of the ring 1.

A tube 23, or socket, is arranged through the central openings of the flat washer 22, the annular seal 21 and the reduction washer 20, the main function of the tube 23 being to connect the ring 1 to the inlet of the box (not shown) of the timepiece implementing the device according to the present invention, specifically to the middle part. The tube 23 further has an outer diameter substantially greater than the inner diameter of the annular seal 21 at rest.

The figures 2 and 3 respectively represent a cross-sectional view of the ring according to the present invention, the constituent elements being assembled, and a perspective view showing in detail the nature of the cooperation implemented between the deformable and rigid elements. These figures make it possible to make clear the interactions existing between the various elements which have just been described in relation to their assembly.

The springs 4 are obtained by a conventional manufacturing process, for example by passing metal sheets in press. Similarly, the barrel 11 for fixing the winding stem is of conventional type. The springs 4 are preferably threaded, or even driven, on the protruding portion 14 of the barrel, that is to say at the end of the barrel opposite the end by which the winding stem is intended to be fixed. Preferably, to ensure a good life of the device, the springs are furthermore welded to the projecting portion 14, possibly by means of a laser beam, on a plurality of contact points located at the interface between the opening 10 of the the central base 5 and the contour of the protruding portion 14.

It may be noted that the springs 4 are self-centered because of their cooperation with the projecting portion 14.

On the other hand, the ring 15 and the washer 17 are also made integral, preferably by laser welding, before the main portion 12 of the barrel 11 is threaded through the opening 18 of the washer 17. head 13 of the barrel is then placed in abutment on the flat surface 24 of the washer 17, while the two springs 4 are arranged opposite the ring 15, more particularly facing the notches 16.

The assembly thus formed of the barrel 11 carrying the springs 4 with the ring 15 and the washer 17 are then driven inside the support member 2. In a non-limiting manner, a laser welding is also applied to the interface between the support member 2 and the outer periphery of the washer 17 to ensure a better durability of the assembly defined above within the support member. We see on the figure 2 that the bottom 3 of the support member fulfills the function of a stop during the operation in which the above assembly is driven into the support member 2.

As mentioned previously, the thickness of the two springs 4 combined is less than the thickness of the ring 15 so that the springs can rotate relative to the axis X1 without being rubbed against the bottom 3 of the element of support 2.

The support member 2 has a shoulder 25 facing the outside of the ring 1 and separating the inside of the support member into two portions of different internal diameters. A first portion 26 located between the bottom 3 and the shoulder 25 has a first diameter substantially greater than the diameter of the ring 15 and the washer 17, while a second portion 27 extending between the shoulder 25 and the the end of the support member located on the side of its opening has a second diameter greater than the first diameter.

The reduction washer 20 is then threaded into the support element 2 so as to be placed in abutment against the shoulder 25. Similarly, the annular seal 21 is forced into the support element 2, bearing against the reduction ring 20. Insofar as the outer diameter at rest of the annular seal 21 is slightly smaller than the second internal diameter of the support member 2, the annular seal is slightly prestressed when in place. Such a measurement, which is conventional, ensures good contact of the annular seal against the inner wall of the support member and therefore a good quality of the seal between these two surfaces.

The assembly of the components thus mounted with each other is then driven inside the lid 1, the latter comprising a housing 28 of generally cylindrical shape and of dimensions slightly greater than the external dimensions of the support element 2. In the region of its opening 29, the cover 1 comprises an annular groove 30 inside which the flat washer 22 is arranged, a small annular shoulder 31 of inner diameter smaller than the outer diameter of the flat washer 22 being provided to retain it in the annular groove 30. From the point of view of the manufacturing method, it may be noted that the flat washer 22 is disposed against a shoulder, corresponding to the side of the groove 30 facing the outside, prior to a crimping operation serving to form the shoulder 31. In addition, the central region of the flat washer 22 is then placed in abutment against the annular seal 21 and ensures re notably its positioning in the direction of axis X1.

The tube 23 is then threaded inside the central space of the housing 28 left empty by sliding against the annular seal. Indeed, the outer diameter of the tube 23 is slightly greater than the internal diameter of the annular seal 21 so as to compress the latter in a radial direction and to reinforce the seal between the annular seal and the support member 2, in addition to guaranteeing the seal between the annular seal and the tube 23. On the other hand, the internal diameter of the tube 23 is slightly greater than the outer diameter of the barrel 11 to allow the free rotation of the latter. It may be noted that during the mounting of the device on a timepiece, the tube 23 is, prior to its mounting in the ring 1, driven into the middle of the timepiece to the level of its shoulder, particularly visible on the figure 2 .

We see on the figure 2 that the barrel 11 has been shown in partial section for clarity. Indeed, it is apparent from this figure that the barrel has an opening at its end facing the outside of the ring 1, to arrange a winding stem end, as previously exposed. In this purpose, the barrel 11 has a central bore 32 having a thread 33 to make a winding rod secured to the barrel by screwing, in a conventional manner.

The figure 3 represents the detail of the relative positioning of the springs 4 with the ring 15 and, more particularly, with the notches 16.

The shape of the springs 4 shown in the figures corresponds to a preferred embodiment illustrated by way of non-limiting example. It is indeed more clearly visible on the figure 3 that the springs each have a curved shape contributing to its properties in terms of elasticity. In particular, it can be noted that at each of the arms 6, a recess 34 is formed partially in the material of the central base 5 and inside the elbow 8, that is to say in the region which undergoes the most important stresses at the moment when the spring undergoes a deformation. The recesses 34 according to the present preferred embodiment have a partially circular outline.

In addition, the second portions 9 of the arms 6 have curved outer surfaces to improve the quality of the contacts with the ring 15 during the rotational movements. More specifically, these external surfaces comprise surface regions 35 which are in contact with long portions 36 of the inner periphery of the ring 15. The long portions 36 have a substantially tangential direction with respect to the axis X1 of the ring and are separated by short portions 37 forming the notches 16, oriented in substantially radial directions.

The long portions 36 of the inner periphery of the ring 15 have a slight curvature, complementary to the curvature that the surface regions 35 of the arms 6 present.

Similarly, the ends 38 of the arms 6 are rounded to limit their friction with the notches 16 when the disengaging device is activated.

The figure 3 shows a part of the disengaging device according to the present invention in a configuration according to which it is not activated. Indeed, the arms 6 of the springs are shown in their rest configuration in which they are in contact with the long portions 36 of the inner periphery of the ring 15 without being deformed or to a negligible extent.

We understand from the representation of the figure 3 and from the foregoing description in relation to the figures 1 and 2 that when the ring 1 is rotated in the counterclockwise direction, it drives the ring 15 and the washer 17 in the same direction. It is obvious in this case that the notches 16 then exert a pressure force on the ends 38 of the spring arms with which they are engaged, thereby causing a rotational movement of the barrel 11 in the same meaning and therefore of the winding stem (not shown). When the arms 6 of the springs undergo a pressing force in this direction via their respective ends, they can practically not deform, in any case as long as the torque transmitted by the ring 15 remains within the a field corresponding to a normal use of the timepiece.

On the other hand, when the ring 1 is rotated in the clockwise direction, it also drives the ring 15 and the washer 17 in the same direction. In this case, the torque is transmitted clockwise from the ring 15 to the springs 4 via the surface regions 35. It then appears that, from the mechanical point of view, when the resistance opposed by the winding stem, via the barrel 11, reaches a certain predefined value, the surface regions 35 can begin to slide with respect to the long portions 36 of the ring 15, due to a beginning of deformation of the arms 6 of springs. Also, when the value of the torque to be transmitted to the springs 4 in order to be able to drive them in the clockwise direction exceeds a predefined value by construction, the long portions 36 of the ring slide on the surface regions 35 of the deformed springs 4, the latter not forming. being consequently more rotated by the rotational movement of the ring 1.

As already mentioned, such a measure avoids, for example, damaging the movement of a timepiece in which the mainspring is recharged by the rotation of the crown, once the it arrived at full load. Thanks to the device according to the present invention, the winding stem is no longer driven in such a case, which makes it possible to preserve the movement of the timepiece.

It may be noted that a significant advantage of the device according to the present invention lies in its simplicity of manufacture and assembly, in particular when it is considered that the components used have relatively small dimensions, the ring generally having a diameter of less than 5. -6 millimeters.

Furthermore, the structure of the device according to the present invention advantageously allows the use of conventional winding rods for the establishment of the crown. In addition, this structure also makes it possible to very simply change the aesthetic appearance of the crown, to meet the requirements of various customers, while limiting the number of components that must be modified in response to the diversity of these requirements. Indeed, a change in the external appearance of the ring is generally sufficient to obtain the desired aesthetic appearance, without the need to change any of the other components of the device according to the present invention.

On the other hand, it can be noted that the described embodiment provides two identical springs 4, which allows to obtain a certain rigidity, adapted to the desired preset torque value. Those skilled in the art can modify the number of springs used to adapt it to their own needs without departing from the scope of the present invention, by arranging more springs to increase the rigidity.

As already mentioned, a choice of materials for the realization respectively of the spring 4 and the rigid ring 15 so that the corresponding hardnesses are close to ensure a longer life of the release device according to the present invention. By way of example, it is possible to use steels of conventional type, for these two elements, whose respective hardnesses are of the order of 500 to 600 HV, to find a compromise between the rigidity of the spring and the frictional wear. of the two elements.

The foregoing description corresponds to a particular embodiment and can in no way be considered as limiting, with particular regard to the form described and shown for the springs and notches with which they cooperate.

In particular, it is easy to see from the figure 3 that by turning the springs 4 and the ring 15 by a symmetry with respect to the plane of this figure, the disengagement function is obtained for the direction of rotation opposite to that described. This particular characteristic confers on the device according to the present invention an additional advantage that the manufacturer can use the same constituents to implement the invention in one direction of rotation or in the other.

Similarly, the form described for the springs 4 is not limiting and any other similar form to achieve the same technical effect can be implemented without departing from the scope of the present invention. More particularly, the number of spring arms 6 described and shown is not limiting in that it constitutes an additional parameter for adjusting the rigidity of the springs employed. Indeed, because of the self centering resulting from the cooperation of the opening 10 of the spring with the protruding portion 14 of the barrel, a single arm 6 may be sufficient to provide the function necessary for the device according to the present invention in connection with the ring 15.

In addition, it is possible to provide variants of the springs and notches 16 of the ring 15 according to which the behavior of the spring is identical in both directions of rotation. In this case, it is possible for example to provide that the notches are made in the form of small recesses formed in the inner periphery of the ring 15, the deformable arms of the springs then extending in substantially radial directions, in other words they do not would not include elbow 8, to react similarly to tangential forces applied at their ends, in one direction of rotation or in the other.

Another possible variant would consist in providing two superimposed stages, each of which would comprise a rigid ring and at least one spring cooperating with notches of the corresponding ring, the respective directions of rotation of the two stages being reversed. In this case, the ring 1 could take two axial positions relative to the winding stem, a single stage being operational in each of the two positions. Such a device would make it possible to obtain the disengaging function of the present invention in two different directions of rotation, each direction corresponding to a given axial position of the ring gear.

Of course, the applications of the present invention are not limited to the winding rods but extend to any other use of a crown rod with the risk of damaging components of the movement of a timepiece.

Claims (16)

1. Crown (1) for a timepiece including a housing (28) of axis X1 inside which are arranged in particular:

   at least one first element (4), able to be deformed resiliently, cooperating in rotation about said axis X1, in at least a first direction of rotation, with a rigid element (15),

   as long as the rotational couple transmitted by one of said elements to the other is less than a predefined value beyond which said first deformable element (4) is capable of being deformed to disconnect the rotational cooperation between said first element and said rigid element (15), characterized in that

   - a pipe (11) including, in the region of a first end, means (33) for securing a winding stem, is disposed within the housing (28) of axis X1

   - said resiliently deformable element (4) is secured to said pipe (11) whatever the value of the rotational couple, whereas said rigid element (15) is fixed in relation to the crown (1), and

   - said deformable element (4) cooperates in rotation with the inner periphery of the rigid element (15) of annular shape.
2. Crown according to claim 1, characterized in that said deformable element is a spring (4) including a central base (5) from which extend at least one and preferably at least two arms (6) that can be deformed resiliently, said rigid element (15) including a plurality of notches (16) arranged opposite said deformable arm(s) (6) and for cooperating with respective surface region(s) (35) of said deformable arm(s).
3. Crown according to claim 2, characterized in that each of said arms (6) includes two successive portions, a first short portion (7) extending from said central base (5) along a substantially radial direction before exhibiting an elbow (8) at substantially right angles extended by the second, substantially rectilinear, portion (9), carrying said corresponding surface region (35) on at least one part of the external edge thereof.
4. Crown according to claim 3, characterized in that each one of said second portions (9) of each arm (6) has one free threaded end (38) ending in a rounded portion.
5. Crown according to claim 4, characterized in that said rigid element is a ring (15) arranged opposite said spring (4) and the internal periphery of which includes alternating first short portions (37) each oriented in a substantially radial direction, forming said notches (16), and second portions (36) longer than said first portions (37) and each oriented in a substantially tangential direction in relation to said axis X1, said second portions (36) being capable of cooperating with said surface regions (35) of each arm (6).
6. Crown according to claim 5, characterized in that, in a direction of rotation corresponding to the direction of inclination of said elbow (8) in relation to the direction of said corresponding first portion (7), said free ends (38) of each arm (6) cooperate with said notches (16) such that a movement of rotation of said rigid element causes a movement of rotation of said spring (4) in the same direction, whatever the value of the transmitted rotational couple.
7. Crown according to any of claims 2 to 6, characterized in that said spring (4) is arranged in the region of the second end of said pipe (11) opposite to said first end.
8. Crown according to claim 7, characterized in that said pipe (11) has, at said second end, a projecting portion (14) substantially aligned with said axis X1 and whose periphery has a non-circular shape, said central base (5) of said spring (4) having a hole (10) substantially aligned with said axis X1 and whose shape is adapted to cooperate with said projecting portion (14) in a movement of rotation.
9. Crown according to claim 8, characterized in that said periphery of said projecting portion (14) has a polygonal shape, preferably a square shape.
10. Crown according to any of claims 5 to 9, characterized in that there is provided a support element (2) secured inside said housing (28) of the crown (1) and of substantially complementary shape to the shape of the latter, said deformable (4) and rigid (15) elements and said pipe (11) being arranged inside said support element (2).
11. Crown according to claim 10, characterized in that said rigid element (15) is secured to said support element (2), whereas said pipe (11) includes a tube (12) and a head (13) of substantially flat annular shape, whose diameter is greater than the diameter of said tube (12), and arranged in the region of said second end of the pipe (11), an additional annular element (17) being secured to said support element (2) abutting against said head (13) of the pipe to hold the latter along the direction of axis X1 while allowing a relative movement of rotation of said two elements in relation to axis X1.
12. Crown according to any of the preceding claims, characterized in that said rigid element (15) is made of a metal or ceramic material.
13. Crown according to claim 12, characterized in that said deformable (4) and rigid (15) elements have respective hardnesses of similar values.
14. Crown according to any of the preceding claims, characterized in that a plurality of identical deformable elements (4) are stacked so as to cooperate with said rigid element (15) in order to increase said predefined rotational couple value.
15. Crown according to claim 8, characterized in that said projecting portion (14) has a thickness at least equal to double the thickness of said deformable element (4), a second stage including additional deformable (4) and rigid (15) elements being arranged in superposition in relation to the first stage in the opposite direction, i.e. to have a similar function to the function of said first stage in the opposite direction of rotation, the crown (1) having at least two axial positions in relation to said winding stem, said first stage operating in a first axial position of the crown whereas said second stage operates in the second axial position.
16. Timepiece including a crown (1) according to any of the preceding claims.

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