Patent Application
20240164494
This application claims priority of European patent application No. EP22207937.8 filed Nov. 17, 2022, the content of which is hereby incorporated by reference herein in its entirety.
The present invention relates to a process for manufacturing a bracelet strand. The invention also relates to a bracelet strand per se, and also to a timepiece comprising such a bracelet strand.
In the field of watch- or clock-making, it is sometimes desirable to add ornamental elements to a bracelet strand. More generally, it may be desired to add various elements and/or functionalities to a bracelet strand.
To produce such an addition, it is necessary to achieve all or some of the following objectives:
Thus, the general aim of the present invention is to propose a solution for manufacturing a bracelet strand comprising at least one complementary element and/or one additional functionality, while at the same time having an aesthetically attractive result, with satisfactory mechanical properties, which is reliable and robust, and easy to obtain, and in a repeatable manner.
To this end, the invention is based on a process for manufacturing a bracelet strand, wherein it comprises the following steps:
The invention also relates to a bracelet strand based on a material, wherein it comprises an insert, and at least one fastening element, resting on the insert or being set on the insert, which are overmoulded by said material, i.e. enveloped at least partially and set by the material.
The invention is more precisely defined by the claims.
These objects, features and advantages of the present invention will be presented in detail in the following description of particular embodiments given on a non-limiting basis in relation to the accompanying figures, in which:
Throughout the text hereinbelow, the adjectives “upper” and “lower” will be used to refer to the future positioning of the bracelet strand. For example, in the case of a bracelet strand, the adjective “lower” denotes the orientation intended to be on the wrist side of a wearer and the adjective “upper” denotes the opposite orientation.
The two half-moulds 22, 23 respectively comprise the walls 221, 231 which are substantially flat and parallel in
The concept of the invention consists in positioning an insert and a fastening element within such a manufacturing mould, before filling the manufacturing mould with a material, so as to overmould the insert and the fastening element, i.e. to envelop them at least partially in said material, in a manner sufficient to set them in the material. This material corresponds to the main material of the bracelet strand and/or to the material that is visible from the upper surface and/or the lower surface of the bracelet strand, and will be referred to hereinbelow as the “material of the bracelet strand” or more simply as the “material”.
The mould may be filled by any means, notably by injection or compression moulding. In the case of an injection moulding process, the material is, for example, injected at a given pressure (typically between 80 bar and 150 bar, or even between 80 bar and 90 bar) into the cavity 21, while the mould is already closed and has a given temperature (typically between 150° C. and 250° C., or even between 150° C. and 200° ° C.). In the case of a compression moulding process, a preform or blank of strand material is positioned on the wall 231 before the mould is closed, and is then compressed at a given temperature (typically between 150° C. and 250° C., or even between 150° ° C. and 200° C.). In all cases, this material is positioned at least partly around one or more fastening elements, so as to envelop them and set them in the bracelet strand: this material thus overmoulds the insert and the fastening element(s).
Advantageously, the material is an elastomer or elastomer-based material, i.e. a material comprising at least 50% by weight of elastomer. In particular, the elastomer material may be a fluoro elastomer (FKM, FFKM or FEPM), or a natural rubber (NR) or synthetic rubber (SBR, HNBR, EPDM), or a vinyl methyl silicone (VMQ) or a fluoro silicone (FVMQ). More generally, the component material may be a polymer. It may notably be a thermoplastic or thermosetting polymer.
In this first embodiment, each guide element 35 is a projecting element, fixed or integrally formed with the insert 15.
As is seen in
This insert 15 serves as a support for the guide element(s) 35 provided for positioning the fastening element(s) 12.
As is seen more particularly in
In this first embodiment, each guide element 35 is in the form of a cylindrical stud which projects from the upper surface of the insert 15, thus extending into the cavity 21 of the mould 20. The contour of the stud at least partially forms the first guide surface 351.
The fastening element 12 is itself in the form of a ring with an aperture 120 which is intended to receive the stud forming the guide element 35. The inner surface of the ring, delimiting the aperture 120, forms the second guide surface 121. In this embodiment, the fastening element 12 extends substantially over the entire height of the cavity 21 of the mould 20 above the upper surface of the insert 15 (apart from the assembly clearance). Advantageously, the fastening element 12 is more precisely a seating ring. It thus comprises a first upper cylindrical portion, defining a central aperture 120, terminating at its base in a disc or a second cylindrical portion arranged around the first cylindrical portion, which defines a seating 12a.
Optionally, a hooking element 14 is associated with the fastening element 12. In particular, this hooking element is in the form of a ring with an aperture 140, the diameter of which is intended for positioning around the fastening element 12, according to a step of the process according to the first embodiment more particularly represented by
As shown in
The process then comprises a second step, represented by
Advantageously, in this second step, the guide element 35 blocks any entry of material or considerably limits the entry of material into the aperture 120 of the fastening element 12. The outer contour of the fastening element 12, for its part, forms at least one binding surface 123 intended to come into contact with the material 11 injected or compressed around it (in particular in the case where there is no hooking element 14, as represented by
In summary, the manufacturing process according to this first embodiment thus comprises the two first steps specified below.
The first step of the process comprises a preliminary sub-step which consists in assembling at least one guide element 35 on an insert 15. This assembling may be performed by any means, other than the screwing described previously. Thus, the guide element 35 may, as a variant, be different from a screw as represented. It should be noted that this preliminary step may also comprise mounting a hooking element 14 around the fastening element 12.
The first step of positioning at least one fastening element 12 in the manufacturing mould is thus obtained by means of this guide element 35, and by means of an insert 15, which is itself preferentially positioned within the manufacturing mould.
The first step thus comprises, for example, positioning the insert 15 on the half-mould 23 of the mould. To do this, pins 41a, 41b are provided for threading, respectively, firstly into loops 152a, 152b of the insert 15, in particular the blade 151, and secondly into portions of housings 24a, 24b formed on the half-mould 23 of the mould. Thus, the blade 151 is positioned within the cavity 21, and is kept suspended at a distance from the opposite longitudinal walls 221, 231 of the mould 20 once the mould is closed.
In summary, the process for manufacturing a bracelet strand comprises the following two sub-steps of a first step of positioning at least one fastening element 12 in a mould:
These two sub-steps may be carried out successively, or in the reverse order, or substantially simultaneously.
Optionally, the first step of the process comprises, in addition to the above sub-steps, another sub-step for positioning a hooking element 14 around a fastening element 12, before or during the positioning of the latter around a guide element 35, as represented by
The manufacturing process then comprises a second step consisting in filling the manufacturing mould 20 with a material so as to overmould, i.e. at least partially envelop and set, the insert 15 and thecu at least one fastening element 12 in the material.
The process then comprises a third step, not represented, which consists in removing the bracelet strand 10 from the manufacturing mould 20. This bracelet strand 10 is thus at least partly formed by the material 11 which has filled the cavity 21 of the mould 20, the insert 15 and the at least one fastening element 12. In this demoulding step, the upper half-mould 22 is separated from the lower half-mould 23, which is fixed according to this implementation example. It should be noted that the result obtained during this demoulding step may only be a rough outline of the bracelet strand, which still requires finishing operations, such as cutting, surface treatment, etc., before obtaining the finished bracelet strand.
After removing the bracelet strand from the mould, the process comprises an intermediate step which consists in removing the at least one guide element 35 from the bracelet strand blank, notably by unscrewing according to the example illustrated. Next, an ornamental element 13 may, for example, be set within the aperture 120 of at least one fastening element 12, notably by driving. Beforehand, any undesired overspilling material 11, notably within the aperture 120, which may result from the second filling step, may be removed via a technique known to those skilled in the art, for instance cryogenic sandblasting. Furthermore, an ornamental element 13 may comprise a chaton 13b within which is set a stone 13a that is visible from the upper surface 101 of the bracelet strand.
According to another variant embodiment which is not represented, the fastening element may be in the form of a simple cylindrical ring. As a variant, this ring may take another shape, for example which extends totally in a direction perpendicular to the upper surface 101 of the bracelet strand, and notably has a cylindrical or frustoconical shape around an axis parallel to this direction, and/or has an annular cross section.
In these embodiments, the use of a hooking element 14 is optional. In the example illustrated by
Moreover, in order to promote the binding of the material 11 around the fastening element(s) 12, their binding surfaces 123, which coincide with the abovementioned receiving surface 124, may be textured via a technique known to those skilled in the art, so as to make them particularly rough. Alternatively or additionally, these surfaces may be coated with a binding primer. According to the variant represented, a binding surface is formed by the outer peripheral surface of the cylindrical ring forming the fastening element 12.
Moreover, the seating 12a of the fastening element 12 is thus embedded in the material 11 of the bracelet strand, i.e. in the thickness of the bracelet strand, since the material 11 extends on either side of the upper and lower surfaces of said seating 12a, the latter being arranged on the insert 15. This embodiment variant allows the bending of the bracelet strand to be minimized locally, around the peripheral surface of the fastening element 12, notably around the first cylindrical portion of the fastening element 12, in particular at the seating 12a formed by the disc or the second cylindrical portion of the fastening element 12.
In these embodiments, the resulting fastening element 12 rests on the insert 15.
The conformation of the ornamental element 13, in particular of the chaton 13b, may be provided so that it can be actuated from the lower surface 102 of the bracelet strand 10. For example, the chaton 13b may comprise an actuating surface 132b projecting from the fastening element 12, i.e. extending deeper into the thickness of the bracelet strand than the fastening element 12, so as to present a lower surface extending parallel or substantially parallel to the lower surface 102 of the bracelet strand, and in the vicinity of this lower surface. Such a surface may, for example, cooperate with dedicated tooling so as to allow disengagement of the ornamental element. Alternatively, the ornamental element 13, in particular the chaton 13b, may be shaped so that it cannot be actuated once it has been assembled within the fastening element 12. By way of example, the chaton 13b may be embedded within the fastening element 12, as will be illustrated with reference to
The process according to the second embodiment constitutes an alternative to the first embodiment. The at least one fastening element 12 is positioned here on the insert 15 not by a guide element 35 previously positioned on the blade 151, but directly within an aperture 155 formed on the blade, acting as guide element 35, as represented by
During the first step represented by
The first step also includes a further sub-step, represented by
After removal from the mould, the process comprises an intermediate step of removing the obstacle 40 formed by the filling material deposited in the aperture 120 of the fastening element 12, to free this aperture 120.
The other steps of the process remain identical to those described with reference to the first embodiment.
In all embodiments, the fastening element 12 may be manufactured from any material that can withstand the temperatures associated with the process. Advantageously, this material is more particularly suitable for enabling the ornamental element 13 to be driven. By way of example, this material may be a metal alloy such as a copper alloy such as brass or CuBez, or even a stainless steel.
In the implementation variants described previously, the fastening elements are intended to receive ornamental elements. They may of course be intended to receive any other element, for example in order to fulfil a new function. For example, in a particular bracelet construction comprising a pin buckle, the apertures of the fastening elements could form a series of aligned apertures, intended to receive the pin and thus participate in adjusting the length of the bracelet. Such a construction would have the advantage of eliminating any deformation of these apertures intended to receive the pin, which are usually formed directly on the bracelet strand by cutting the material. A fastening element according to the invention may thus fulfil various functions, and there is therefore not necessarily a permanent fixing of a different element in a fastening element.
Moreover, as described previously, in all the implementation variants, a fastening element may be in the form of a ring, optionally comprising a seating. Such a seating has the advantage of locally limiting the bending of the strap strand around the fastening element. Needless to say, the invention is not limited to the form of the fastening elements as represented, which may take any other form depending on the functionality required. For example, a fastening element may be in the form of a cylindrical or frustoconical ring or any other shape, arranged around an axis, for example of annular shape in cross section to said axis. Preferentially, in all the implementation variants, the fastening element, in particular the ring acting as a fastening element, comprises a surface which is flush with the upper surface of the bracelet strand.
In the embodiments described, a fastening element is positioned in a mould by means of at least one guide element. Such a guide element may be in various forms. For example, it may be an element projecting in a certain direction into a cavity of the manufacturing mould, notably arranged symmetrically around an axis parallel to said direction, notably cylindrical or frustoconical in shape and/or circular in cross section to said axis.
Furthermore, in all the implementation variants, the fastening element may or may not be combined with a hooking element, the latter being provided to maximize the anchoring of the material constituting the envelope of the component around the fastening element. Preferentially, a hooking element may be made of aluminium or titanium foam.
As described previously, an ornamental element may be in the form of an assembly such as a stone set within a bezel. The stone may, for example, be a natural stone such as a precious stone (diamond, ruby, sapphire, emerald) or a fine stone, for instance jasper. The stone may also be organic, and may, for example, be in the form of a pearl or mother-of-pearl. The bezel may, for example, be manufactured from a precious alloy such as a gold-based alloy.
Alternatively, the ornamental element may be made in one piece. For example, it may be manufactured from a ceramic, for example a ceramic mainly or predominantly composed of zirconia, or alumina, or silicon nitride, or boron carbide, or aluminium nitride. Alternatively, the ornamental element may also be made of a composite material such as an alumina-zirconia ZTA/ATZ composite. Alternatively also, the ornamental element may be made of a precious metal alloy such as a gold or platinum based alloy. Moreover, it may comprise a pattern.
Moreover, the insert notably advantageously fulfils a reinforcing function. Moreover, this insert has been described as being in the form of a blade. Naturally, such a blade may occupy different surfaces, extend substantially continuously over a significant dimension of a bracelet strand, for example over at least 50% or even 70% of its length, or, as a variant, take on a restricted dimension, being located solely at the fastening element(s). Furthermore, the invention is not limited to a blade-shaped insert.
The invention also relates to a timepiece, notably a wristwatch, comprising such a bracelet strand.
| Number | Date | Country | Kind |
|---|---|---|---|
| 22207937.8 | Nov 2022 | EP | regional |
