Bracelet strand with optical effect

Abstract

The invention relates to a bracelet strand made of transparent or translucent elastomer material, comprising a first end suitable for connection with a watch case, characterized in that it comprises a rigid insert having a solid part forming a reinforcement, and a hollow part arranged to receive a fluid and solid elements dispersed in the fluid, said hollow part being located in the center of the solid part, and in that the insert is coated in the transparent elastomer, and is positioned at the first end suitable for connection with a watch case.

Description

Technical field of the invention

[0001] The invention relates to a watch strap with an optical effect.

[0002] The invention also relates to a method of producing a watch strap with an optical effect. Technological background

[0003] Traditionally, watch straps are made of leather, synthetic material, fabric, rubber, or metal. Straps also include an insert placed in a lining or sheath or between an upper and lower band that are then joined together. This insert has a primarily mechanical and flexible function.

[0004] In the case of a rubber strap, it is common to use an insert made of a mechanically resistant rigid material. This insert can be made by injection using a thermoplastic material such as polyamide alone or filled (carbon fibers, glass fibers, etc.). Once the insert is made, it is placed in the mold and the rest of the strand made of rubber is overmolded (by injection or compression) around it.

[0005] Currently, optical or decorative effects can be added to the strap, but it is noted that their integration is difficult to guarantee sufficient protection against different environmental conditions, shocks or even abrasion when wearing the watch.

[0006] One example is patent application EP 0 373 806, which describes a watch strap. The strap comprises a transparent plastic pocket filled with a liquid and particles, the pocket being housed between a lower and an upper part of the strap and being visible through an opening in the upper part. However, it does not define sufficient protection of the pocket against environmental conditions and against shocks or abrasion, which is a disadvantage. In addition, the overall thickness of such a strap is often too great and the pocket remains visible, which also detracts from the aesthetics of the strap. Summary of the invention

[0007] The invention aims in particular to overcome the various drawbacks of the bracelets of the prior art.

[0008] More specifically, one objective of the invention is to provide a bracelet strand with an optical effect having a controlled thickness while guaranteeing good protection of the optical effect.

[0009] To this end, the invention relates to a bracelet strand made of elastomer material, comprising a first end suitable for connection to a watch case, characterized in that it comprises a rigid insert having a solid part forming a reinforcement, and a hollow part arranged to receive a fluid and solid elements dispersed in the fluid, said hollow part being located at the center of the solid part, and in that the insert is coated in a transparent elastomer forming the bracelet strand, said insert being positioned at the first end suitable for connection to a watch case.

[0010] According to other advantageous variants of the invention: the particles have a density greater than that of the fluid; the fluid is chosen from: an aqueous solution or a vegetable or mineral oil; the solid elements are chosen from: 3D or 2D metal particles, phosphorescent particles or even beads; the insert is made from a transparent, amorphous or very low crystallinity polymer; the insert has mechanical strength with a Young's modulus greater than 1 GPa; the insert comprises a metal blade arranged to be in contact with a case middle; the hollow part is in the form of a logo, a letter, a number or a pattern; the insert comprises two shells, each shell comprising a cavity forming the hollow part; the insert comprises a channel opening onto the hollow part to fill the latter.

[0011] The invention also relates to a method of manufacturing a bracelet strand according to the invention, the method comprising the following steps: providing a transparent insert comprising a hollow part; providing a fluid and adding solid elements to it to form a solution with suspended particles; injecting the solution obtained into the insert via a channel opening into the hollow part; closing the channel in a sealed manner; overmolding a transparent or translucent elastomeric material onto the insert to form a bracelet strand, then vulcanizing or “cooking” the overmolded material until a flexible strand of elastomeric material is obtained comprising an insert with a hollow part so that the solution with the suspended particles is visible from the outside of the bracelet strand. Brief description of the figures

[0012] Other characteristics and advantages of the invention will appear on reading the following detailed description given by way of non-limiting example, with reference to the appended drawings in which: there figure 1 represents a sectional view along a median plane in the length direction of a bracelet strand according to the invention; the figure 2 represents a sectional view seen in section along a median plane in the height direction of a bracelet strand according to the invention; the figure 3 represents a top view of a bracelet strand according to the invention. Detailed description of the invention

[0013] In reference to the figure 1 , it represents one of the two strands of a watch strap, flexible, which together form a watch strap and which each carry an insert 2.

[0014] The watch strap strand 1 comprises a first end 10 capable of receiving a fastening bar and being attached to a watch case by means of this fastening bar. The strap strand 1 is pierced with holes 11 succeeding one another over a portion of its length, each of the holes 11 being provided for the passage of a buckle member or a pin making it possible to attach the watch strap strand 1 to the other watch strap strand and thus close the watch strap, for example around a wrist.

[0015] The watch strap strand 1 is in the form of a flexible band of elastomer material and comprises an insert 2 onto which the band of flexible material is overmolded.

[0016] The elastomer forming the bracelet strand is elastically compressible and is not well suited to attachment to the watch case, an insert 2 is therefore integrated by overmolding at the first end of the strand 1 which is intended to be connected to the watch case.

[0017] According to the invention, the first end 10 capable of connection with a watch case comprises a rigid insert 2 forming a reinforcement and increasing the rigidity of the strand near the watch case.

[0018] The insert 2 comprises a solid part 20 and a hollow part 21 formed in the center of the solid part and arranged to receive a fluid 3 as well as solid elements 4 dispersed in the fluid.

[0019] Advantageously, the solid elements 4 have a density greater than the liquid in which they are located in order to allow them to flow when the bracelet strand is set in motion or agitated.

[0020] The solid elements 4 are chosen from: 2D or 3D metallic particles, phosphorescent particles, microbeads, glitter, lamellae, etc.

[0021] Fluid 3 is chosen from: water, oil, etc. and can be colorless or colored. Obviously, the fluid must be transparent or translucent to allow the solid elements to appear.

[0022] According to a preferred embodiment of the invention, the insert 2 is coated in a transparent elastomer forming the bracelet strand 1 to be able to observe the hollow part receiving the fluid and the solid elements dispersed in the fluid. The elastomer is intended to be transparent or translucent, and is made from crosslinked materials of the FKM or silicone type but also from non-crosslinked materials of the thermoplastic elastomer type such as TPE-U or TPE-S.

[0023] Depending on the needs of the person skilled in the art, the hollow part 21 is in the form of a logo, a letter, a number or even a pattern.

[0024] According to yet another embodiment, the insert 2 has a logo, a letter, a number or a pattern formed in positive relief housed in a corresponding opening of the bracelet strand and forming the hollow part of the insert.

[0025] This insert 2 is made of a non-compressible material such as a thermoplastic. In this example, the insert 2 is in the form of a parallelepiped element. The insert thus makes it possible to make the end connected to the watch case extremely rigid.

[0026] Advantageously, the insert is made from a transparent, amorphous or very low crystallinity polymer such as PEF, PET, polycarbonate, polyamide or polymethyl methacrylate, epoxy or PUR.

[0027] The insert is produced via molding, 3D printing or even machining.

[0028] The insert has mechanical resistance with a Young's modulus greater than 1GPa in order to be able to withstand the tensile / torsional / bending stresses of the bracelet during its installation and use.

[0029] According to one embodiment of the invention, the insert is reinforced with a metal blade 5 at the first end of the strand 1 which is intended to be connected to the watch case in order to ensure good tensile and tensile / torsion resistance of the bracelet, the metal blade 5 being arranged to be in contact with the watch case when the bracelet strand is attached to the latter.

[0030] In order to be able to fill the hollow part of the insert 2, the latter comprises a channel 22 opening onto the hollow part to fill the latter, the fluid mixture and solid elements being injected into the hollow part by means of a syringe for example.

[0031] The bond between the bracelet strand 1 and the insert 2 can be improved by an adhesion promoter or mechanical attachment elements, and thus avoid detachment of the insert during overmolding and repeated bending of the bracelet strand when it is used. Different adhesion promoters can be used depending on the material pair used.

[0032] According to a second embodiment of the invention, the insert is in the form of two shells arranged to be assembled by means of a joint, a weld or an adhesive, each shell comprising a cavity forming the hollow part.

[0033] The invention also relates to a method of manufacturing a bracelet strand provided with an insert.

[0034] The process of making a bracelet strand includes the following steps: a) providing a transparent insert comprising a hollow part; b) providing a fluid and adding solid elements to it to form a solution with suspended particles; c) injecting the solution obtained into the insert via a channel opening into the hollow part; d) closing the channel in a sealed manner; e) overmolding a transparent or translucent elastomeric material onto the insert to form a bracelet strand, then vulcanizing or “cooking” the overmolded material until a flexible strand of elastomeric material is obtained comprising an insert with a hollow part so that the solution with the suspended particles is visible from the outside of the bracelet strand.

[0035] The invention also relates to a watch comprising at least one bracelet strand according to the invention.

[0036] Thanks to these different aspects of the invention, we have a bracelet strand presenting an optical effect with good mechanical resistance.

[0037] Of course, the present invention is not limited to the illustrated example and is susceptible to various variants and modifications which will appear to those skilled in the art, without departing from the scope of the invention as defined by the claims.

Claims

1. Bracelet strand (1) made of a transparent or translucent elastomer material, comprising a first end (10) capable of connecting to a watch case, characterised in that it comprises a rigid insert (2) having a solid part (20) forming a reinforcement, and a hollow part (21) arranged to receive a fluid (3) and solid elements (4) dispersed in the fluid, said hollow part being located at the centre of the solid part, and in that the insert (2) is coated in the transparent elastomer, and is positioned at the first end (10) capable of connecting to a watch case.

2. Bracelet strand (1) according to claim 1, characterised in that the particles have a higher density than the fluid.

3. Bracelet strand (1) according to claim 1 or 2, wherein the fluid is selected from: an aqueous solution or a mineral or vegetable oil.

4. Bracelet strand (1) according to one of claims 1 to 3, wherein the solid elements are selected from: metal particles, phosphorescent particles, beads, flakes or scales, etc.

5. Bracelet strand (1) according to one of claims 1 to 4, characterised in that the insert is made of a transparent polymer that is amorphous or that has a very low crystallinity.

6. Bracelet strand (1) according to one of claims 1 to 5, characterised in that the insert has a mechanical strength with a Young's modulus greater than 1 GPa.

7. Bracelet strand (1) according to one of claims 1 to 6, characterised in that it comprises a metal blade arranged such that it is in contact with the watch case.

8. Bracelet strand (1) according to one of claims 1 to 7, characterised in that the hollow part takes the form of a logo, a letter, a number or a pattern.

9. Bracelet strand (1) according to one of claims 1 to 8, characterised in that the insert comprises two shells, each shell comprising a cavity forming the hollow part.

10. Bracelet strand (1) according to one of claims 1 to 9, characterised in that the insert (2) comprises a channel (22) opening out into the hollow part (21) so as to fill the latter.

11. Method for manufacturing a bracelet strand according to one of claims 1 to 10, characterised in that it comprises the following steps of: a) taking a transparent insert comprising a hollow part; b) taking a fluid and adding solid elements thereto to form a solution with suspended particles; c) injecting the solution obtained into the insert via a channel opening out into the hollow part; d) closing the channel in a leak-tight manner; e) overmoulding a transparent or translucent elastomer material over the insert to form a bracelet strand, then vulcanising or "curing" the overmoulded material to obtain a flexible strand made of an elastomer material and comprising an insert with a hollow part such that the solution with the suspended particles is visible from outside the bracelet strand.

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