EP1416341B1 - Connection device between a bezel and a watch case - Google Patents

Description

The present invention relates to a connecting device between a bezel and a watch case comprising a first axial retaining surface secured to the box, adjacent to a cylindrical seat, a second opposite axial retaining surface formed by a face of a an annular groove integral with the bezel, an annular polymer retaining element bearing against each of said bearing surfaces, said first bearing being adjacent to the base of a conical surface, integral with the box, for the axial insertion of said annular retaining element in engagement with said annular groove, this annular retaining element allowing the removal of the telescope when a force greater than its resistance is applied to the telescope.

A device of this type has already been proposed in EP 0 770 937 in which a rotating bezel is fixed by means of a split ring made of a plastic material of the "circlip" type. Since such a method of fixing a bezel is not reversible, to remove the bezel, it is necessary to exercise on this split ring a shearable traction. This is made of polymer capable of breaking when sufficient axial traction is applied to the bezel. To ensure that the split ring can return to its original shape after having been expanded by the conical introduction surface, this ring must preferably be made of a plastic material having an elastic limit or, more commonly, a flow threshold corresponding to early creep, and relatively high shear strength. These conditions are however unfavorable for the dismantling of the telescope since they require the exercise of a high force on the bezel that may leave marks on the bezel and on the box. In addition, such a mode of connection between the bezel and the box only applies to rotating spectacles.

JP 10-39049 relates to a bezel formed of two rings, one of which has different segments and serves for attachment to the middle part and the second ring secondly. This ring is divided into two substantially symmetrical parts by a slot in an arc of a circle, perpendicular to the plane of the ring. The sections of these two parts are substantially symmetrical by rotation of 180 ° about an axis passing through the center of the slot. The inner portion has an internal projection which allows to hang it to a scope of the middle and the outer portion has an outer projection, rotated 180 ° relative to the inner projection which allows to hang on the second ring. The thicknesses perpendicular to the plane of the ring 12 of the two hooking parts are practically identical. These two parts are thus fixed permanently to one another and the middle, their removal is not provided, it can not be done without damaging the elements of the box.

The object of the present invention is to overcome, at least in part, the aforementioned drawbacks and limitations.

For this purpose, this invention relates to a connecting device between a bezel and a watch case, according to claim 1.

The main advantages of this invention are the use of an annular ring-shaped retaining element and the fact that the section of this ring has two rectangular parts, one of which has a substantially smaller thickness than the other. The part of the section of the thin ring is to be destroyed when the bezel is removed. Advantageously, the material used for the manufacture of the endless ring is a thermoplastic elastomer. Such a ring makes it possible at the same time to easily assemble the pieces together, to hold them well and to disassemble them easily, thanks to the thin part of the ring, without any risk of damaging the box, the bezel or the two pieces.

The transition from fastening mode "clipping" to that using an endless ring does not go without saying, contrary to what one might think at first glance. Indeed, the thinner part of the ring must press substantially all over its face, or attached to its section, over virtually its entire radial length, this as well to ensure a secure attachment of the bezel that to be sheared during the removal of the telescope. However, during the establishment of the bezel provided with this ring, it must expand by passing over a conical surface before retracting and to support under the scope, taking an inner diameter corresponding to that of its cylindrical seat secured to the box. During this expansion, it is necessary that a space corresponding substantially to this expansion, is provided between the outer surface of the larger section portion of the retaining ring and the adjacent surface of the bezel. As explained above, this space should be as small as possible.

This also means that the radial dimension of the scope holding the retaining ring and therefore the bezel must also be very small, which is possible only if the edge of this scope is sharp. Indeed, if this were not the case, the fixing of the telescope would not be ensured. An advantage resulting from the very small clearance between the outer surface of the thickest portion of the retaining ring and the adjacent surface of the bezel is to allow the centering of the bezel.

The retaining ring made of thermoplastic elastomer still has the advantage of serving as a braking element for a rotating bezel when it is separated from the middle part by elastic means and retained by a non-cylindrical surface of this retaining ring. . Given the importance of the surfaces contributing to the braking of the telescope, a slight manual pressure in the opposite direction allows to release the telescope to rotate it.

Another very important advantage resulting from the use of a retaining ring made of a soft polymer, especially a thermoplastic elastomer, comes from the fact that it is not limited to the attachment of rotating spectacles, as is the case with a "circlip", but it also allows to fix non-rotating glasses, as will be seen in the following description.

• La figure 1 est une vue partielle en coupe diamétrale d'une boîte de montre comprenant une première forme d'exécution de ce dispositif;
• la figure 2 est une première vue partielle en coupe diamétrale d'une boîte de montre comprenant une deuxième forme d'exécution de ce dispositif;
• la figure 3 est une vue semblable à la figure 2 dont la coupe diamétrale est décalée angulairement;
• la figure 4 est une vue en plan de la partie solidaire de la carrure autour de laquelle est fixé le dispositif de liaison;
• la figure 5 est une vue partielle en coupe diamétrale d'une boîte de montre comprenant une troisième forme d'exécution de ce dispositif;
• les figures 6 et 7 sont des vues très partielles de deux variantes de la figure 5;
• la figure 8 est une vue partielle en coupe d'une variante de la figure 1;
• la figure 9 est une vue partielle en coupe diamétrale d'une boîte de montre comprenant une dernière forme d'exécution de ce dispositif.

Other features and advantages of the present invention will appear on reading the following description which will be made with the aid of the accompanying drawings which illustrate, schematically and by way of example, several embodiments of watch cases whose glasses are fixed using the connecting device object of the present invention.

• Figure 1 is a partial view in diametral section of a watch case comprising a first embodiment of this device;
• Figure 2 is a first partial view in diametral section of a watch case comprising a second embodiment of this device;
• Figure 3 is a view similar to Figure 2, the diametral section is angularly offset;
• Figure 4 is a plan view of the integral part of the middle part around which is fixed the connecting device;
• Figure 5 is a partial view in diametral section of a watch case comprising a third embodiment of this device;
• Figures 6 and 7 are very partial views of two variants of Figure 5;
• Figure 8 is a partial sectional view of a variant of Figure 1;
• Figure 9 is a partial view in diametral section of a watch case comprising a last embodiment of this device.

The watch case illustrated in FIG. 1 comprises a middle part 1 to which a bottom 2 is screwed with the interposition of a seal 3. An ice sheet 4 is sealingly attached above the upper opening of the middle part 1 by an annular ice seal 5 that extends around ice 4 and an upper part of the middle part 1. A clamping ring 6 serves to exert a centripetal pressure on the annular ice seal 5, to fix the ice-cream 4 tightly on the middle part 1.

The outer lateral face of the clamping ring 6 has a conical surface 6a followed by a cylindrical surface 6b whose diameter is slightly smaller than that of the base of the conical surface 6a adjacent, thus providing a bearing surface 6c between the two surfaces 6a. , 6b.

A rotating bezel 7 is mounted on the middle part 1 by means of rolling balls 8 pressed in a direction parallel to the axis of the middle part 1 by springs 8a in a raceway 7b. These bearing balls 8 springs are at least three in number distributed at equal angular distances from each other.

The connecting device between this bezel 7 and the caseband 1 comprises an annular retaining element 9 made of a polymeric material, whose section has two parts 9a, 9b, each in this example of rectangular section. The part 9a is inside, while the part 9b is outside the element 9. The thickness of the part 9b, that is to say its dimension perpendicular to the plane of the annular element 9 is substantially smaller than that of the portion 9a, thus forming a flange 9b around the thicker inner portion 9a. Preferably, the flange 9b is located in the middle of the thickness of the inner annular portion 9a.

This flange 9b is engaged in an annular groove 7a of the bezel 7 and its lower annular flat face comes into contact with the lower edge of this annular groove 7a perpendicular to the plane of the annular retaining element 9, forming a bearing surface lower 7a ₁ . The upper annular flat face of the annular portion 9a thicker of the annular retaining element 9 is in contact with the bearing surface 6c of the clamping ring of the ice seal 5, which forms an upper bearing surface.

Advantageously, the annular retaining element 9 is made of a thermoplastic elastomer (TPE) which, among other things, has the advantage of being able to be manufactured by injection, and therefore with very precise dimensions. Such a material has sufficient elasticity to expand radially and regain its initial shape during the positioning of the telescope 7. It is especially a material that has a low modulus of elasticity, a low limit of rupture tensile and low flow threshold. Thanks to these properties, the collar 9b can have a sufficient thickness to be able to make the retaining element 9 by injection, while allowing this collar 9b to tear during the removal of the bezel 7 without having to exert a force too much. high, which would be likely to damage the telescope 7, or even the middle 1 also. TPEs suitable for the manufacture of the retaining element 9 are sold in particular under the trademark Hytrel®.

To assemble the bezel 7 on the middle part 1, it is first necessary to drive the ice 4 provided with the gasket 5 and the clamping ring 6 onto the part 1a of the caseband 1. Then, the retention element 9 is introduced. , in particular its flange 9b in the groove 7a of the bezel 7. This assembly is placed around the conical surface 6a of the clamping ring, the smaller diameter of which substantially corresponds to the internal diameter of the retaining element 9. then exerts an axial force on the bezel 7 to bring the entire bezel 7, retaining ring 9 in the position shown in Figure 1.

During its displacement along the conical surface 6a, the retaining element 9 undergoes radial expansion. Given its properties, it resumes its initial diameter, or even a slightly larger diameter, in case the diameter of the surface 6b of the clamping ring is slightly greater than its initial diameter. In all cases, it is necessary for the inner face of the retaining element 9 to be in close contact with the cylindrical surface 6b of the clamping ring 6, so that the bearing surface 6c ensures the axial locking of the retaining element. 9. This axial locking must be sufficient to prevent this retaining element 9 to cross the scope 6c during the removal of the bezel 7. In this case, the axial force exerted on the bezel 7 must shear the collar 9b.

However, this shearing of the flange 9b can be obtained only if the diametral clearance between the outer cylindrical surface 9c located under the collar 9b of the portion 9a of the retaining element 9 and the inner cylindrical surface of the bezel 7, located below the annular groove 7a is between 1 and 2 times the radial dimension of the span 6c, which brings the radial distance between these two adjacent cylindrical surfaces between 1/2 and 1 times the radial dimension of the span 6c.

The radial dimension of this span 6c must be as small as possible, while allowing to ensure the locking of the retaining element 9 as explained above. The reasons for the need of this small dimension are twofold. On the one hand, it is required because of the use of an annular ring retainer 9, on the other hand it is also required by the small clearance that must exist between the outer cylindrical surface 9c of the element retaining 9 and the adjacent cylindrical surface of the bezel 7, to ensure a good support of the flange 9b and therefore a good holding of the bezel 7 and allow the shearing of the flange 9b during the removal of the bezel 7. Well that the material used for the retaining element is preferably a thermoplastic elastomer which tolerates a certain compression, it can only be very small, of the order of 2 or 3 hundredths of a millimeter. But the radial dimension of the span 6c of the clamping ring must be it of the order of 10 hundredths of a millimeter, provided to ensure a sharp edge between the scope 6c and the conical surface 6a.

It follows from the above that if the clearance between the cylindrical surface 9c of the retaining element 9 and the adjacent cylindrical surface of the bezel 7 is small, these two cylindrical surfaces can advantageously be used to guide the telescope 7, which would not be possible with a fastening type "circlips".

It has been mentioned up to now that the retaining element 9 is advantageously made of a thermoplastic elastomer, since it has a good chemical resistance and allows its initial shape and diameter to be resumed after being dilated. radial during the establishment of the bezel 7 and it does not require the application of too great a force likely to damage the bezel and / or the middle to shear the collar 9b, while allowing to give a thickness at the flange, compatible with its production by injection.

However, it would be possible to use other polymers. It may be mentioned in particular PolyOxyMéthilène POM which is an acetal resin, such as Delrin® 100ST whose Young's modulus = 1400 MPa, the flow threshold = 43 MPa and the ultimate tensile strength = 45 MPa. Polybutylene terephthalate PBT such as Crastin® ST820 may also be mentioned, whose Young's modulus = 1600 MPa, the yield point = 35 MPa and the tensile rupture limit = 40 MPa.

Of course, other polymers suitable for the production of this retaining element 9 may be found. It is also possible to choose polymers having a higher yield point or tensile strength limit, depending on the desired properties. One can also play on the dimensions, in particular on the thickness of the flange 9b depending on the material chosen and the desired properties.

The second embodiment illustrated in FIGS. 2 to 4 differs from the previous embodiment essentially in that the connecting device is used for fixing a fixed window 17.

The only change between this embodiment and the previous one comes from the fact that the outer cylindrical face 16c of the clamping ring 16 of the ice seal 15 is interrupted at regular angular distances distributed by three sectors 16d of larger radii, as illustrated. FIGS. 2 and 4. These sectors 16d form no longer 16c with the base of the conical surface 16a. These sectors 16d instead form an obtuse angle α with the conical surface 16a, preferably forming themselves a slight inclination cone opposite to that of the conical surface 16a.

With this conformation of the clamping ring 16, only its three sectors 16b still have a scope 16c, the latter disappearing in the sectors 16d. Figure 3 shows the retaining element 19 located in a sector 16b where it is retained by the bearing 16c and wherein the bezel 17 is retained by the collar 19b as in the previous embodiment. FIG. 2 shows a sector 16d of the clamping ring 16 which exerts a radial compression on the retaining element 19 by expanding it. Thanks to this compression of the retaining element between the clamping ring 16 on the one hand, and the bottom of the annular groove 17a of the bezel on the other hand, the bezel 17 is immobilized by rotation, which allows to use the connecting device according to the present invention also for fixing fixed glasses.

The embodiment illustrated in FIG. 5 also relates to the fixing of a fixed telescope 27. In order to immobilize this telescope 27, a compressible seal 30 made of a material with a high coefficient of friction is compressed between the telescope 27 and the telescope 27. middle 21. The annular retaining member 29 is retained as in the previous embodiments by the bearing 26c of the clamping ring 26 of the seal 25 of the ice 24. An advantage of this embodiment is to allow, during the introduction of the telescope 27, to compress the seal 30 such that the annular retaining member 29 descends below the bearing 26c of the clamping ring 26. As soon as the pressure on the bezel 27 ceases, the seal 30 then applies the retainer 29 against the scope 26c. Given the compression of this seal 30 and the high friction material of which it is made, the bezel can not rotate.

The variant illustrated in FIG. 6 differs from the embodiment of FIG. 5 only in that the annular retaining element 29 and the immobilization seal 30 of the telescope are joined into a single composite annular member AB comprising two pieces 29a, 30b of different materials, glued to each other. Each of these parts 29a, 30b plays the same role as the retaining element 29, respectively the seal 30.

In the variant illustrated in Figure 7, there is the annular retaining member 39 and the compressible seal 40 of the telescope. However, in this variant, the seal 40 is compressed radially by the telescope 37 and not axially as in the case of Figures 5 and 6.

FIG. 8 represents a variant of FIG. 1 in which the crystal 54 is fixed in a flange 51a of the middle part 51. In this variant, the retaining element 59 comes into direct contact with a bearing surface 51c formed on the external lateral face. of the middle part 51, at the base of the conical surface 51b, serving as an axial stop for the retaining element 59 in the same manner as in the previous embodiments. There is shown in this variant a rotating bezel 57. One could of course achieve a fixed spectacle mount according to this variant, adapted to one of Figures 5 to 7 in particular.

The last embodiment illustrated in FIG. 9 comprises a bezel in two concentric annular parts, one inner 67A, the other outer 67B, connected to one another by a split elastic ring 67B ₁ of the type " circlips ", secured to the outer portion 67B. This elastic ring 67B ₁ forms an axial retaining surface, against which a surface 67A ₂ of the inner portion 67A of the bezel bears against, allowing the outer portion 67B to rotate relative to the inner portion 67A. In this embodiment, a pivotal locking pawl 68 is engaged with a positioning recess 67A ₁ provided on the underside of the inner portion 67A of the bezel and immobilizing it. Other means of immobilization could replace the pivot ratchet 68.

The inner portion 67A of this two-part bezel is connected to the box middle 61 by the annular retainer 69, in the same manner as in the embodiments described above. The removal of this telescope will be done by removing the two parts 67A, 67B, these being integral in their axial displacement although free to rotate relative to each other.

Claims (13)

1. Linking device between a bezel (7) and a watch case (1) comprising a first axial retention boss (6c) secured to the case (1), adjacent to a cylindrical seat (6b), a second, opposite axial retention boss (7a₁) formed by one face of an annular groove (7a) secured to the bezel (7), an annular retention element (9) made of polymer bearing against each of said bosses (6c, 7a₁), said first boss (6c) being adjacent to the base of a conical surface (6a), secured to the case (1), for the axial introduction of said annular retention element (9) engaged with said annular groove (7a), this annular retention element (9) allowing the removal of the bezel when a force greater than its resistance is applied to the bezel (7), characterized in that said annular retention element (9) forms a ring of solid cross section that is divided in the radial direction into two portions (9a, 9b), one of which is, perpendicular to the plane of said ring, substantially thinner than the other, capable of being sheared by removal of the bezel these two portions (9a, 9b) being intended to interact respectively with said first boss (6c) and second boss (7a₁).
2. Device according to Claim 1, in which said ring is an endless ring.
3. Device according to one of the preceding claims, in which said first axial retention boss (16c) is interrupted on three equidistant angular segments (16d) to form circular sectors for the compression of said annular retention element (16) between these circular sectors and the bezel (17) in order to immobilize the latter.
4. Device according to either one of Claims 1 and 2, in which a friction element (30; 30b; 40) is interposed between the case (21) and the bezel (27) in a position for fixing the latter.
5. Device according to Claim 4, in which said friction element (30; 30b; 40) is made of a compressible material.
6. Device according to one of the preceding claims, in which at least one of the outer circular surfaces (9c) of said annular retention element (9) forms a surface for positioning the bezel (7).
7. Device according to Claim 6, in which the radial dimension of said first axial retention boss (6c) lies between one and two times the diametral clearance between the bezel (7) and said outer circular surface (9c) of said retention element (9) forming a surface for positioning the bezel (7).
8. Device according to one of the preceding claims, in which said bezel comprises two portions (67A, 67B) mounted one inside the other, having guidance elements (67B₁, 67A₂) allowing them to be made to rotate one in relation to the other, one of these two portions (67A, 67B) being connected to the watch case (1) by said annular retention element (69).
9. Device according to one of Claims 1, 2, 6 to 8, in which elastic means (8a; 30; 30b) exert axial pressure against said annular retention element (9; 29; 29a).
10. Device according to Claim 9, in which said axial pressure is exerted via rolling means (8).
11. Device according to one of the preceding claims, in which the tensile strength of the polymer forming said annular retention element (9) is less than 100 MPa.
12. Device according to either one of Claims 1 and 2, in which the polymer forming said annular retention element (9) is a TPE.
13. Device according to one of the preceding claims, in which the polymer forming said annular retention element has a Young's modulus of less than 2500 MPa and a yield strength of less than 60 MPa.

Images