EP2440085B1 - Bracelet made up of articulated links - Google Patents

Description

The present invention relates to a bracelet formed of elements articulated together, in particular links, at least some of which are preferably made at least in part of a low-resilience material. The invention also relates to a particular use of such a bracelet for watches, jewelery pieces or even ornaments.

The integration into the bracelets of hard materials and generally having a low resilience, namely of materials sensitive to mechanical shocks, is essentially to provide a high durability (scratch and wear resistance) and an added value of aesthetic order to the object they garnish. The latter is usually made of a metal frame that is necessary for it to be able to withstand heavy mechanical stress, accidental type, such as those involved in a fall.

Unlike metals and alloys obtained by casting, materials such as those made by hot solidification of a paste or a compressed powder, generally have a low resilience and are therefore particularly sensitive to mechanical shocks. This sensitivity results from the absence of plastic deformations of these materials during impacts. This feature leads the parts that are made of such materials to a so-called fragile break.

Among the fragile materials, defined as such under conditions of normal temperature and reduced impact speeds, examples include sintered hard metal, any type of ceramic including zirconia, glass and minerals such as sapphire or the ruby.

The documents EP 586 981 and EP 347 841 describe wrist bracelets, especially for wristwatches, the visible parts of which are formed of decorative elements made of hard materials, such as ceramic or sintered hard metal. The bracelet comprises an armature made by links of machinable material such as steel. In both cases, the ceramic elements are only intended to cover the links of the frame which will bear all the mechanical forces applied to the bracelet. Thus, the mechanical stresses that these decorative elements undergo are severely limited.

The document US 2002/0009019 suggests another construction bracelets formed of a succession of ceramic links, each forming an entity consisting of a central mesh lined with two lateral meshes offset from the first. These three meshes are held together by means of a threaded shaft at its ends, which are intended to be screwed into threads molded in the side meshes. The joints and the assembly of the various successive links are obtained by a spring bar passing through the central mesh and provided with an elastic member housed in its central portion. This member is intended to separate two studs, slidably mounted at the ends of the bar, so that they can be inserted into housings formed in correspondence in the side meshes.

The main disadvantage of such an embodiment stems from the fact that this kind of bracelet leads to a rupture of one or more ceramic meshes, as it has been found during tests reproducing accidental drops of a connected watch. to this type of bracelet. During such a fall, the mass that represents the case added to that of the movement of the watch, causes great efforts on the axes or bars of the bracelet, mainly by a lever effect between the point of impact on the ground of the bracelet and the fixing of the latter to the middle part of the watch. The location of the rupture is almost systematically at the axes of articulation of the links. Simulations have shown that large stresses are concentrated in the entrance angles of the ceramic mesh holes. It was also noticed that all the breaks occurred in the direct vicinity of the axes, on the edges of the ceramic meshes. The breaking of a mesh or a link of such a bracelet makes the latter unusable and generates significant repair costs requiring the replacement of broken elements.

The document EP2057914 discloses another example of a bracelet comprising a plurality of elements comprising a mesh articulated together by means of a connecting member disposed within a hole forming a housing within a mesh. It is useful to reduce the sensitivity of the meshes vis-à-vis any shocks.

The object of the present invention is to obviate the aforementioned drawbacks by producing, in accordance with the terms of claim 1, a bracelet comprising a plurality of elements articulated together, called links and each formed of at least a mesh and having at least one housing for receiving a connecting member associating the stitches and / or the links between them. This bracelet has a design that makes the mesh less sensitive to accidental mechanical shocks.

Certain meshes are preferably at least partly made of a brittle material, such as ceramic, a sintered hard metal, glass or a sapphire or ruby type mineral, for example. The articulated elements of this bracelet will preferably be engaged in each other so as to be closely interconnected by the connecting members, namely members or hinge pins and possibly assembly rods. Preferably of the number of two or three, these connecting members are housed in the mesh or meshes of the link, each in a housing formed of at least one mesh hole.

According to the invention, in the immediate vicinity of the open ends of at least some mesh holes, preferably meshes of low resilience and in particular at least holes reserved for the passage of a hinge pin, there is provided a deflection of the connecting member which, locally, locally prevents this member from coming into contact with the mesh. Thus, and according to the preferred embodiment of the invention, each deflection offers, in the direct vicinity of the edges of the meshes from which the connection members project, a free space or at least one gap which prevents the transmission of concentrated efforts to these meshes. on these bodies at these ends, when the latter are subjected to mechanical stresses.

Advantageously, this means avoids any breakage of the meshes which, by nature or because of the abnormal temperature conditions in which they could be placed, are or become sensitive to mechanical impacts.

According to the preferred embodiment, the freedom or the range of motion thus reserved for the connecting member by the deflection means is obtained by reducing its cross section to the right of opening the hole in the mesh. Such a reduction can be achieved by machining on this member of a groove that can have different widths and / or profiles depending on the desired performance. Such an organ, also called grooved axis, will comprise at least as many grooves as there are open ends among the set of fragile meshes it passes through.

• La figure 1 est une vue en perspective et en coupe partielle d'une portion de bracelet selon le mode de réalisation préféré de l'invention.
• La figure 2 est une vue en coupe verticale du bracelet selon la ligne II-II de la figure 1.
• Les figures 3a à 3d sont des vues agrandies de différents profils de gorges que peuvent adopter les axes et/ou tiges liant les mailles ou maillons du bracelet.
• La figure 4 est une vue similaire à la figure 2 mais dans laquelle le bracelet comprend en variante que trois rangées de mailles.
• La figure 5 est une variante de l'illustration représentée à la figure 4.

Other advantages and specific features will become apparent in the light of the description which follows and which refers to a preferred embodiment of the subject of the invention as well as to variants, taken as a non-limiting and illustrated schematically and by way of example by the appended figures in which:

• The figure 1 is a perspective view in partial section of a bracelet portion according to the preferred embodiment of the invention.
• The figure 2 is a vertical sectional view of the bracelet along line II-II of the figure 1 .
• The Figures 3a to 3d are enlarged views of different groove profiles that can adopt the axes and / or rods linking the links or links of the bracelet.
• The figure 4 is a view similar to the figure 2 but in which the bracelet comprises as a variant that three rows of stitches.
• The figure 5 is a variant of the illustration shown in the figure 4 .

With reference to the figure 1 , this illustrates a bracelet portion 1 in a perspective view and in partial section. As shown, this bracelet is a watch strap made on a five-row design R ₁ to R ₅ with meshes 2, 3, 4 forming a plurality of elements articulated together. According to this arrangement, the so-called edge stitches 2, situated on the rows R ₁ and R ₅ , as well as the so-called center stitches 3, arranged on the row R ₃ , are judiciously made of resilient materials such as metals (steel , gold, titanium, etc ...) or alloys. By this arrangement, the stitches on the rows R2 and R4, called intermediate stitches 4, are thus protected by the rows of adjacent stitches. For this reason, it is these intermediate meshes that will preferably be chosen to be made at least partly of low or low resilience material. Preferably the intermediate meshes 4 will be entirely made of ceramic, more particularly in zirconia known as a so-called technical or industrial ceramics. It will of course be understood that other materials could also be used for the execution of these meshes. Among these materials, we will still prefer sapphire or ruby to the sintered hard metal, for example.

The different meshes 2, 3, 4 are connected to each other by at least one connecting member 10 in particular by three connecting members 10, 11, 12 as illustrated in FIG. figure 1 . With the exception of a few singular links, such as the fixing 5 located between the horns of the middle part of the watch, or even the connecting links attached to the clasp of the bracelet, the articulated elements of the bracelet each comprise at least two connecting members, in particular two axes of articulation 10. Each of these connecting members is common to several meshes, in particular to all the meshes of the same line as well as to certain meshes of the adjacent lines upstream and downstream. In this regard, it will be pointed out that the lines thus defined correspond to a succession of adjacent meshes forming a line transverse to the rows R ₁ to R ₅ . The adjectives upstream and downstream refer to the distance of the element in relation to fixing 5 or intermediate fixing meshes 6 which are particular meshes intended to connect the bracelet 1 to the middle part of the watch (no shown). Thus, with respect to a given point, the meshes located upstream will be closer to fixing than the meshes located downstream.

The edge stitches 2 and the center stitch 3 of the same line are aligned and hold between them two intermediate stitches 4 which are offset downstream with respect to this alignment. All of these five meshes form on its own the entity that will be called link 7 and which is illustrated in FIG. figure 1 by the contour line shown in broken lines. The links 7 constitute the articulated elements of the bracelet. They each have at least one mesh. The meshes of the same link are held together rigidly, that is to say without articulation between them, by at least one rod called assembly rod 11, preferably by two connecting rods 11 and 12. links 7 are all similar to each other and given the positions offset downstream of the intermediate meshes 4, the links 7 can interlock with each other, that is to say engage some in the others to be closely related, and to be assembled from upstream to downstream in an articulated linkage through the axes 10. These are defined as being precisely axes of articulation which give two adjacent links a cylindrical articulation of simple type , comparable to a hinge.

The articulated elements 7 each comprise at least one housing formed of at least one hole 15, better visible on the figures 2 , 4 and 5 , to receive a connecting member 10, 11, 12. Preferably and as illustrated on the figure 1 these organs are hidden in the meshes they connect. They are not apparent on the outer faces of the edge meshes 2, nor even visible between the meshes 2, 3, 4 because of the very low interstitial clearance between these meshes. The latter are therefore advantageously provided with blind holes 15 ', while the holes 15 of the center stitches 3 or the intermediate stitches 4 are of the through type to allow the passage of the connecting members 10, 11, 12. , the holes 15 and 15 'of the same line form a housing for a connecting member.

With reference to the figure 2 , this represents the bracelet with five rows of the previous figure, in a vertical sectional view along the line II-II of the figure 1 . According to this line II-II, the cut occurs on the hinge pin 10. It will be noted that at least at each open end 16 holes 15 formed in the meshes intermediate 4, in this case the so-called low resilience meshes, is a clearance 20 of the assembly member which passes through these open ends or mouths of the holes 15. For all practical purposes, it will be specified that the term mouthpiece, used here, as synonymous with the open end 16 of the hole 15, designates the zone located in the immediate vicinity of the inlet or outlet of this mesh hole.

By this means, the means offered by the deflection 20 of the connecting member in question prevents it from coming into contact with the mesh at a location near the opening of the hole of the mesh. Thus, when this axis or connecting member is subjected to an elastic deformation stress which induces locally, at the interface of two meshes or mesh portions arranged side by side, a bending of the corresponding section of this member, any contact between this stump and mesh can be advantageously avoided. Therefore, the first point of support between the mesh and the connecting member is moved towards the central portion of the mesh. By pushing this support towards the inside of the mesh, it avoids so-called edge effects that generate on the mesh concentrations of significant stress openings and would cause fatigue or premature rupture of the mesh when the link of the bracelet is subject to a mechanical shock.

According to the preferred embodiment, the deflection 20 results from an interval or clearance located between the connecting member and the corresponding mesh. This distance or separation distance is obtained by reducing the cross section of the connecting member to the right of the open end 16, by the accommodation on the connecting member of a groove 21 whose profile may be the same. a straight groove 21, a groove 21 chamfered, a groove 21 with rounded edges, a groove 21 with progressive curvature or a groove 21 formed of a combination of these geometries. These different forms of grooves are illustrated by way of example in Figures 3a to 3d . The Figures 3c and 3d show combinations where the groove 21 is on one chamfered side and the other has a rounded edge, respectively a progressive curvature edge. Advantageously, a groove which has a progressive curvature on its side oriented towards the inside of the mesh allows, when the portion of the connecting member which passes through it is subjected to a mechanical stress, to gradually distribute the stress of the mesh on a beach extending from its central portion to the edges of this mesh. With this gradual distribution, any concentration of efforts in the edges of the mesh can be avoided, at least limited, very convincingly.

Such a progressive curve could be that adopted by the shape of a barrel portion. Advantageously, this shape makes it possible to further stress the center of the mesh rather than its edges when an elastic deformation occurs in the portion of the assembly member passing through this mesh. Thus, this form best promotes the distribution of mechanical stresses along the portion of this organ. In addition, in terms of mechanical failures, it has been found that the barrel geometry more solves the connecting members than the meshes.

Preferably, all the connecting members 10, 11, 12 will be of circular section and have an outer diameter of between 1.0 and 2.0 mm, more particularly between 1.4 and 1.6 mm. The diameter at the bottom of the grooves 21 of the grooved pins will be reduced by a value of between 5% and 25%, more particularly between 11% and 15%, of the outer diameter of the axis. The latter can also vary along the axis, especially when the diameter of the holes of the center stitches differs somewhat from that of the holes of the mesh of edge. The values equivalent to an outside diameter of 1.5 mm for a groove with a minimum diameter of 1.3 mm will be preferred because they correspond to the best compromise between the resistance of the axis and the importance of the clearance resulting from the groove. In fact, such dimensions make it possible to obtain good performance in terms of impact resistance by leaving a sufficient interstitial space between the bottom of the groove and the edge of the mesh, at the opening of the hole of the axis when bending under load of it. This game remains in all cases effective, even taking into account the tolerances applied to the functional dimensions of the hole drilling diameter and the diameters on the axis.

In a variant illustrated in figure 5 the deflection 20 of the axis could consist of a free space or clearance obtained by the arrangement, in the mesh, of an inlet cone open towards the outside of this mesh and located at the opening of the hole reserved for the passage of the assembly member. Such an entry cone would consist of a pronounced widening or widening of the orifice of the opening of the mesh hole and would also reduce, although less effectively, the edge effects on this mesh while having a connecting member devoid of throat to the right of the open ends. More generally, this clearance could be defined as being an opening 22 of the open end 16. It will be further specified that a simple chamfer, such as that visible on the meshes 2 or 3 of the figure 2 does not constitute a clearance in the sense that it must be understood here, namely a clearance sufficiently effective to fulfill the function that the present invention attributes to it. Indeed, any simple chamfer will only serve to facilitate the engagement of the member, to eliminate machining burrs or may simply arise from a requirement in the case for example of a manufacture resulting from a process of molding.

According to another embodiment, the deflection could be obtained by a toric or cylindrical member such as a sleeve, made of a very resilient material and which would act as a damper. Such a material would therefore be able to absorb the mechanical stresses occurring in the connecting member in order to avoid transmitting them to the mesh or at least generating a concentration of forces in its edges. To do this, this sleeve could be arranged around the connecting member, hidden in the edges of the mesh, in the vicinity of the open ends of the hole reserved for this body. Alternatively, by placing this sleeve in a groove of the connecting member, it could also fill the gap between the bottom of the groove of the wall or inner surface of the hole of the mesh at its open end.

According to a combined embodiment, it could also be possible, in addition to the deflection means 20 constituted by the grooves 21 of the connecting member, to widen the open end of the hole 15 from which this axis projects by a cone. open entrance to the outside of the mesh.

In all cases, the deflection 20 of the assembly member in question aims to distribute any bias transmitted to the mesh, as a result of forces induced in the connecting member, over a range extending from the central portion from this stitch to the edges of the latter. For all practical purposes, it will be noted that the term "clearance" here defines the amplitude of the possible movement of the connecting member, in particular portions of this member located opposite the open ends 16, around its position relative to its position. equilibrium materialized by the axis of the dwelling in which it rests.

As illustrated in figure 1 , the assembly rods 11 and 12 are devoid of grooves 21 to the open ends 16. However, this does not exclude anything the arrangement in the present bracelet 1 of one or more connecting rods 11, 12 similar or identical to the axis of articulation 10. In a more general manner, it could be envisaged to provide for each open end 16 whatever it may be, a deflection 20 of the connecting member which protrudes therefrom. Thus, all the assembly members 10, 11, 12 of the meshes 2, 3, 4 could be members provided with grooves 21 as described above. The resistance and the final performance of the links of the bracelet would thus be further improved.

More preferably, the assembly rods 11, 12 may have smooth surfaces or be provided with knurled bearings to improve their strength within the mesh they connect. In particular, such knurled lands will preferably be located at the ends of the assembly rods intended to be housed in the holes 15 'of the edge mesh 2. Also, the assembly rods 11, 12 devoid of grooves 16 will be maintained hunted within the mesh, unlike the grooved pins which, to prevent buckling, will preferably be adjusted with a slight tightening in the holes 15 during assembly.

The figure 4 illustrates a variant of the mesh design of the bracelet 1, according to a view similar to the figure 2 but in which the mesh arrangement comprises only three rows R ₁ ', R ₂ ', R ₃ '. Thus, if the edge meshes 2 remain unchanged, the center stitches and the intermediate stitches of the same line are here replaced by a single intermediate stitch 4 ', preferably made of a material of low resilience. Through this figure, it will be noted that the object of the present invention is in no way dependent on the arrangement of the stitches within the various links of the bracelet, nor of the number of these, nor of the material in which they are performed.

Thanks to the solution provided by the invention, it has been found, in tests carried out on a bracelet conforming to that shown in FIG. figure 1 , that the bracelet was able to withstand stresses resulting from an impact of a watch equipped with this bracelet and weighing 240g on an oak block after being dropped from a height of 1.3m. These results have shown that the object of the invention makes it possible to increase the impact resistance of the bracelet by a factor of 2.5 compared to a bracelet whose hinge pins are devoid of grooves at the openings of the holes of the bracelet. mesh that they cross. Indeed, a breakage of the intermediate meshes at the hinge axes is systematically noted at heights of less than 0.5 m for such bracelets.

It will be noted that the object of the invention was developed first to solve the problem of breaking ceramic mesh during accidental impacts on the bracelet. However, it will be noted that the proposed solution would apply equally well to bracelets whose meshes are not particularly sensitive to mechanical shocks. Thus, in the case where the mesh of the bracelet would all be made of metal, for example steel, gold or any alloy, the solution provided by the present invention would also help to avoid the edge effects in the mesh and to relieve and the open ends of the holes of the connecting members, a fatigue resulting from an undesirable concentration of effort.

Claims (11)

1. A bracelet (1) comprising a plurality of articulated elements (7) that each include at least one link (2, 3, 4, 4'), wherein at least part of said links is in a material of low impact resistance and has at least one housing including at least one hole (15, 15') to receive therein a linking member (10, 11, 12) of said articulated elements (7), characterized in that a clearance (20) is provided in the vicinity of the open ends (16) of at least some of said holes (15, 15') formed in said links in a material of low impact resistance to prevent contact at this location between the linking member (10, 11, 12) and said links (2, 3, 4, 4').
2. The bracelet (1) claimed in claim 1, characterized in that said linking member is an articulation pin (10) or an assembly rod (11, 12) and in that said clearance (20) is obtained by a local reduction (21) of the cross section of this linking member (10, 11, 12).
3. The bracelet (1) claimed in claim 2, characterized in that said local reduction has a profile which is that of a straight groove (21), a chamfered groove (21), a groove (21) with rounded edges or progressive curvature or a groove (21) formed of a combination of these profiles.
4. The bracelet claimed in claim 1, characterized in that said clearance (20) is produced by a relief forming a flaring (22) of said opening (16).
5. The bracelet claimed in claim 1, characterized in that said clearance (20) is produced by a toroidal or cylindrical damper member produced in a resilient material and disposed between the linking member (10, 11, 12) and the link (2, 3, 4, 4').
6. The bracelet (1) claimed in claim 2 or claim 5, characterized in that said clearance (20) further comprises a flaring (22) of said opening (16).
7. The bracelet (1) claimed in claim 1, characterized in that at least one of said links (2, 3, 4, 4') is produced at least in part in a non resilient or low resilient material.
8. The bracelet (1) claimed in claim 7, characterized in that said material is a ceramic, a sintered hard metal, glass or a mineral such as sapphire or ruby.
9. The bracelet (1) claimed in claim 2, characterized in that said linking member (10, 11, 12) provided with local reductions (21) of its cross section is retained by a snug fit in the articulated elements (2, 3, 4, 4', 7) that it links.
10. The bracelet (1) claimed in claim 1, characterized in that said articulated elements (7) are each formed by an alternation of at least one link (4, 4') in a non resilient or low resilient material and links (2, 3) of greater resilience.
11. Use of the bracelet (1) claimed in any one of the preceding claims as a watchstrap or as a jewelry item.

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