DEVICE FOR ATTACHING A WRISTBAND

Description

Technical field of the invention

[0001] The present invention relates to the field of watchmaking or jewelry. More specifically, it concerns a device for attaching a bracelet to an object, in particular a watch case. Technological background

[0002] Generally, watch straps, whether leather or metal, are attached to the lugs of a watch case by means of a bar consisting of a tube in which two pistons are mounted, moving in a linear fashion. An elastic element positioned between these pistons tends to push them outwards from the tube. This bar is mounted in a housing specifically designed for this purpose at one end of the strap, and the pistons engage in blind bores machined opposite each other in the lugs of the case.

[0003] To detach a bracelet from a watch case, a tool is needed that pushes the spring bars back into the tube, against the resistance of the spring bar, thus removing them from the bores. The wearer of the watch does not always carry such a tool, and moreover, its use can be cumbersome. Therefore, bracelets with this type of fastening are generally permanently attached to the case.

[0004] Furthermore, there are fastening devices that allow the bracelet to be detached from the case without the use of tools. Such devices typically include a bar, of the type described previously, on which a piston actuating element is mounted, passing through the tube. This actuating element is, for example, a radial finger attached to one of the pistons, as described in Swiss patent CH 327 838. The finger is mounted to slide through an axial slot in the tube, and its movement along the slot pushes one of the pistons back into the tube.

[0005] Patent CH 614 589 describes a watch case with a device for attaching a strap to the case. The central lug has a cylindrical passage split longitudinally along its entire length, allowing the insertion of a bar for attaching a strap. The bar is cylindrical with a flat section along its entire length, allowing the bar to pass through the passage and holding it in place when it reaches a specific angular position.

[0006] We also know of such a device from document EP 3 709 103.

[0007] The fastening devices described above are generally used for interchangeable bracelets, allowing the wearer to change them as desired. However, they are not without drawbacks. In particular, they require major structural modifications to the spring bar, such as creating an opening in the tube or altering the pistons. These changes result in significant additional manufacturing costs. Furthermore, these fastening devices have a prominent component—the actuation mechanism—which can snag on or injure the wearer. Summary of the invention

[0008] The invention aims in particular to overcome the various drawbacks of prior art bracelet fastening devices.

[0009] To this end, the invention relates to a device for attaching a bracelet to a watch case, at the level of two pairs of lugs, by means of at least one female connecting element arranged to be integral with the watch case and at least one male element arranged to be integral with one end of the bracelet, these elements being complementary to cooperate by fitting one into the other constituting removable assembly means capable of making the bracelet interchangeable.

[0010] According to the invention, each of the male elements consists of a rod arranged to be connected to a corresponding end of the bracelet, at each end of the rod, by a ball ratchet and by a first and second cylindrical shouldered parts arranged concentrically around each ball ratchet, each ball ratchet and each first and second cylindrical shouldered parts being arranged to cooperate respectively with a blind housing and a groove near the blind housing, the blind housing and the groove forming the female connecting elements arranged on internal areas of the two pairs of lugs.

[0011] In accordance with other advantageous variants of the invention: Each female connecting element comprises a ramp arranged upstream of the blind housing, the ramp being arranged to cooperate with the ball ratchet, the blind housing being located at the end of the ramp; the groove comprises successively a straight portion and an arcuate portion; the groove comprises a first stop element to limit the rotation of the rod; the first shouldered portion has a height greater than the radius of the axis, and the second shouldered portion has a height less than the radius of the rod; the first shouldered portion locally has a notch at its periphery, the notch defining the angular stroke length of the rod and being arranged to cooperate with a second stop element; the second stop element is superimposed on the first stop element and offset relative to the first stop element;Each female connecting element is designed to be attached to the inner areas of the two pairs of lugs; each female connecting element is made of a metallic material or metallic alloy; the end of the bracelet includes a passage arranged to receive the stem; the bracelet is fixed to the stem.

[0012] The invention also relates to a watch equipped with a fastening device according to the invention. Brief description of the figures

[0013] Other features and advantages of the invention will become apparent from the following detailed description, given by way of non-limiting example, with reference to the accompanying drawings in which: there figure 1 represents an exploded perspective view of a bracelet attached to a watch case by means of a fastening device according to the invention; the figure 2 represents a cross-sectional view along axis AA of the figure 1 ; there figure 3represents an exploded view of a fastening device according to the invention; the figures 4a , 4b and 4c illustrate respectively a perspective view, a cross-sectional view, and a front view of a male part of a fastening device according to the invention; the figure 5 represents a perspective view of a female part of a fastening device according to the invention; the figures 6a and 6b represent respectively cross-sectional views of a fastening device according to the invention in the inserted position and in the locked position. Detailed description of the invention

[0014] There figure 1 illustrates a watch case equipped with a device for attaching a strap to a watch according to the invention.

[0015] The fastening device 1 is intended to secure the ends 20, 21 of a bracelet 2 to a watch case 3, at the level of its lugs 4.

[0016] The bracelet is attached to the case by means of a fastening device 1 comprising a female connecting element 5, attached to the lug 4 of the watch and a male element 6 attached to the end 20, 21 of the bracelet 2, the female element 5 and the male element 6 being complementary and cooperating by fitting into each other, to constitute removable assembly means capable of making the bracelet interchangeable.

[0017] According to the invention, each of the male elements consists of a cylindrical rod 7, with longitudinal axis AA, disposed at a corresponding end 20, 21 of the bracelet 2. This rod 7 is extended on both sides by a ball ratchet 8 housed in a cylindrical cavity 84 centered on the axis AA.

[0018] Typically, the ball ratchet 8 consists of a body 81 in which a spring 83 and a ball 82 are housed, the body 81 resting in the cylindrical cavity 84.

[0019] Each of the male elements also includes first 70 and second 80 cylindrical shouldered parts arranged concentrically around each ball ratchet 8, the first cylindrical shouldered part 70 partially encircling the ball 82 of the ball ratchet 8.

[0020] The bracelet includes, at each of its ends 20, 21, a passage arranged to receive the rod 7 and hold it in place. The rod 7 is fixed to the bracelet and is prevented from rotating relative to the bracelet by means of pins securing the rod to the bracelet.

[0021] Each cylindrical shouldered part is formed by the intersection of two planes orthogonal to each other, one of the planes being perpendicular to the longitudinal axis AA of the rod 7, and the other plane being parallel to this same longitudinal axis AA.

[0022] According to the invention, each female part 5 comprises a blind housing 50 arranged to cooperate with the ball ratchet 8, and a groove 51 arranged to cooperate with the second cylindrical shouldered part 80, the blind housing and the groove forming the female connecting elements on internal areas of the two pairs of horns 4.

[0023] As depicted in the figure 5 Each female connecting element 5 includes a ramp 52, arranged upstream of the blind housing 50, to cooperate with the ball ratchet 8 and guide the latter to the blind hole 50 located at the end of the ramp 52. According to this arrangement, the blind hole 50 is raised relative to the bottom of the groove 51.

[0024] Advantageously, the groove 51 includes successively a first straight portion 51' and a second circular arc portion 53 in order to be able to insert the second cylindrical shouldered part 80 in translation into the first straight portion 51' until the ball ratchet engages in the blind hole 50, then to rotate the rod 7 until it is placed in the bearing position.

[0025] Thus, the first straight portion 51' of the groove 51 runs along the ramp 52 and the second arc-shaped portion 53 goes around the blind hole, thus forming a continuous groove 51 guiding the rod 7 in translation and then in rotation.

[0026] As can be seen in figures 4a And 4bThe first cylindrical shouldered section 70 and the second cylindrical shouldered section 80 are formed one after the other and have different dimensions so as to form steps of different heights. The first cylindrical shouldered section 70 has a height H that is greater than the radius r of the rod 7, and the second shouldered section has a height h that is less than the radius r of the rod 7.

[0027] The first cylindrical shouldered part 70 allows a clearance for the ball 82 of the ball ratchet 8, the body 81 of the ratchet 8 being flush with the first cylindrical shouldered part 70 and the ball 82 being projecting relative to the plane formed by the surfaces of the body 81 of the ratchet and the first cylindrical shouldered part 70.

[0028] The second cylindrical shouldered part 80 is arranged to cooperate with the groove 51, the second cylindrical shouldered part 80 being introduced into the groove 51 via an opening 60 directed outwards and giving access to the groove 51 and the ramp 52, the height h of the second cylindrical shouldered part 80 being of similar dimensions to those of the straight portion 51' of the groove 51 so that the second cylindrical shouldered part 80 slides in the straight portion 51'.

[0029] As can be seen in the figure 5 , the groove 51 includes a first stop element 54 which is arranged to cooperate with a flat 90 of the second shouldered part 80 so as to limit the rotational stroke of the rod 7.

[0030] The female connecting elements include a second stop element 55 to limit the rotation of the rod 7. This second stop element 55 is formed recessed and higher relative to the first stop element 54. The second stop element 55 is arranged to cooperate with the first shouldered portion 70, which locally has a notch 71 at its periphery, the length of the notch 71 defining the length of the angular stroke of the rod 7. The notch 71 has at its end a contact surface 72 arranged to cooperate with the second stop element 55.

[0031] Such an arrangement with two stop elements 54, 55 allows for greater strength and increased safety given that the parts and surfaces in contact are small in size.

[0032] According to one embodiment of the invention, each female connecting element 5 is an element attached to the internal zones 40, 40' of the two pairs of horns. As illustrated in the figure 3 , each female connecting element 5 is screwed onto an internal area 40, 40' of a horn.

[0033] According to another embodiment, not illustrated in the figures, each female connecting element 5 is directly machined on the internal areas 40, 40' of the two pairs of horns.

[0034] Each female connecting element 5 is made of a metallic material, a metallic alloy, a plastic material, or a ceramic material. If the female connecting element 5 is attached to the horn 4, it is possible to combine materials, for example, to have a metallic or metallic alloy horn and a female connecting element 5 made of ceramic or plastic.

[0035] To attach the bracelet 2 to the case 1, the first and second shouldered parts 70, 80 are inserted as illustrated in the figure 4a , corresponding to the ends of the rod 7 attached to the bracelet, by presenting them facing the openings 60 of the female connecting elements 5.

[0036] Once the first and second shouldered parts are inserted into the opening, the wearer slides the pin 7 (or the bracelet) to the bottom of the straight portion 51' of the groove 51, the groove 51 guiding the second shouldered part 80. A "click" allows the pin 7 to be positioned relative to its axis of rotation thanks to the engagement of the ball ratchet 8 in the blind housing 50. This also serves as a reference point for the wearer, the engagement of the ball ratchet 8 in the blind housing 50 indicating that the wearer can now rotate the bracelet 2, and therefore the pin 7, into the wearing position, thus preventing the pin 7 from dislodging itself from the female connecting elements 5.

[0037] Once the ball ratchet 8 is engaged in the blind housing 50, the user rotates the rod 7 around the axis AA via the bracelet until the bar rotates at least 90° around the axis AA relative to its insertion position, or until the first and second shouldered parts 70, 80 come into contact with the first and second stop elements 54, 55, thus preventing the bracelet from being dislodged, as can be seen in the figure 6b .

[0038] To remove the bracelet, simply reverse the steps and apply slight pressure to the bracelet to disengage the ball ratchets 8 from the blind housings 50.

[0039] In the embodiment described above, the device is described for a flexible bracelet made of leather, synthetic fabric, or elastomer. The device is also adaptable to a bracelet made of metal or ceramic links, for example.

[0040] Thanks to these different aspects of the invention, we have a secure bracelet fastening device that allows the bracelet to be changed easily and quickly without the aid of tools.

[0041] Of course, the present invention is not limited to the illustrated example and is susceptible to various variants and modifications which will become apparent to those skilled in the art.

Claims

1. Device (1) for fastening a bracelet (2) to a watch case (3), at two pairs of horns (4), by means of at least one female connecting element (5) arranged to be secured to the case (3) of the watch and at least one male element (6) arranged to be secured to one end (20, 21) of the bracelet, these elements being complementary so as to cooperate by fitting one into the other, while forming removable assembly means capable of making the bracelet interchangeable, wherein each of the male elements consists of a rod (7) arranged to be connected to a corresponding end (20, 21) of the bracelet (2), and, at each end of the rod (7), by a ball-pawl (8) and by a first (70) and second (80) cylindrical shouldered portions arranged concentrically around each ball-pawl (8), each ball-pawl (8) and each first and second cylindrical shouldered portion (70, 80) being arranged to cooperate respectively with a blind housing (50) and a groove (51) proximate to the blind housing (50), and the blind housing (50) and the groove (51) forming the female connecting elements (5) arranged on inner areas of the two pairs of horns (4).

2. Fastening device (1) according to claim 1, wherein each female connecting element comprises a ramp (52) disposed upstream of the blind housing (50), the ramp (52) being arranged to cooperate with the ball-pawl (8), the blind housing (50) being at the end of the ramp (52).

3. Fastening device (1) according to claim 1 or 2, wherein the groove (51) successively comprises a rectilinear portion (51') and an arcuate portion (53).

4. Fastening device (1) according to claim 1 or 2, wherein the groove (51) comprises a first stop element (54) for limiting the rotation of the rod (7).

5. Fastening device (1) according to one of claims 1 to 4, wherein the first shouldered portion has a height (H) larger than the radius (r) of the rod (7), and the second shouldered portion has a height (h) smaller than the radius (r) of the rod (7).

6. Fastening device (1) according to one of claims 4 or 5 when depending on claim 4, wherein the first shouldered portion (70) locally has a notch (71) at its periphery, the notch (71) corresponding to the length of the angular travel of the rod (7) and being arranged to cooperate with a second stop element (55).

7. Fastening device (1) according to claim 6, wherein the second stop element (55) is superimposed on the first stop element (54) and offset relative to the first stop element (54).

8. Fastening device (1) according to one of claims 1 to 7, wherein each female connecting element (5) is an element intended to be attached to the inner areas (40, 40') of the two pairs of horns (4).

9. Fastening device (1) according to one of claims 1 to 8, wherein each female connecting element (5) is made of a metal material or metal alloy.

10. Fastening device (1) according to one of claims 1 to 9, comprising said bracelet (2) wherein the end (20, 21) of the bracelet (2) comprises a passage arranged to receive the rod (7).

11. Fastening device (1) according to one of claims 1 to 10, comprising said bracelet (2) wherein the bracelet (2) is secured to the rod (7).