Process for manufacturing a composite block used for the manufacture of a piece of jewelry or watchmaking

Abstract

The present invention relates to a method for manufacturing a composite block made of a gold, silver, or platinum alloy, the composite block being formed by assembling at least two parts made of different metallic materials chosen from said alloys. This composite block is used for the manufacture of a jewelry or watchmaking item. The method comprises the following steps: a) forming at least one part having a hollow region, b) assembling the parts using a technique chosen from among chasing, powder sintering, melting, welding, ultrasonic welding, three-dimensional printing and shrink fitting, c) obtaining a composite block.

Description

Title of the invention: Method for manufacturing a composite block used for the manufacture of a piece of jewelry or watchmaking Technical field of the invention

[0001] The present invention relates to a method for manufacturing a composite block of precious metal, in particular an alloy of gold, silver, or platinum, by assembling at least two parts made of different metallic materials chosen from these alloys, as well as to such a composite block. The invention also relates to a piece of jewelry or timepiece obtained from the composite block, as well as to its manufacturing method. Technological background

[0002] In the field of jewelry and watchmaking, it is common to assemble layers of different metallic materials, particularly precious or semi-precious metals, in order to form composite parts such as laminates.

[0003] In this regard, document US 2927070 describes a method for manufacturing a multi-layer composite, by stacking several colored sheets, bonding them to obtain a laminate, producing a pattern on the surface of the laminate, clipping the portions of the pattern which protrude from the main surface, and rolling the laminate. This type of method makes it possible to obtain optimal bonding of the layers of the colored laminate.

[0004] Document EP 2279825 describes a method for assembling several gold alloy parts by brazing. A layer of tin is first applied to the surfaces of the parts intended to come into contact. The parts are then glued using a press and then heated to a high temperature, thus leading to the final laminated assembly.

[0005] Another example of assembly is described in document FR 2460744, which relates to a composite metallic material and its manufacturing method. The composite material is formed from several different metallic materials linked together by metallic bonding, and which forms a pattern representing flames of different colors.

[0006] These different processes make it possible to manufacture composite materials made up of several different metallic materials, which have different colors, so as to obtain original patterns for jewelry or watch pieces made from these composite materials.

[0007] However, it remains necessary to develop other techniques for manufacturing such composite materials, so that watchmakers and jewelers can choose the technique best suited to their specifications. Brief description of the invention

[0008] An aim of the invention is to provide a method of manufacturing a composite block making it possible to overcome the aforementioned drawbacks.

[0009] The invention also aims to provide such a manufacturing method making it possible to form a composite block, which is ideally suited to the manufacturing of a piece of jewelry or watchmaking which is itself composite, particularly those which require the formation of a pattern made up of several different metallic materials.

[0010] To this end, the invention proposes a method for manufacturing a composite block made of a gold, silver or platinum alloy, the composite block being formed by assembling at least two parts made of different metallic materials chosen from said alloys, the method comprising the following steps: a) forming at least one part having a hollow region, advantageously by removing at least one region of material, b) assembling the parts, by inserting at least one solid region of at least one of the parts into a hollow region of at least one other of said parts, the solid region(s) inserted into a hollow region at least partially filling said hollow region by shape complementarity, the assembly being carried out using a technique chosen from among chasing (hot or cold), powder sintering, casting, welding (without adding material), ultrasonic welding, three-dimensional printing and shrink fitting, c) obtaining a composite block.

[0011] In the method according to the invention, the assembly of the parts can be carried out using different techniques: - Chasing: tightening between at least two parts to be assembled. - Powder sintering: machining of a first part, then sintering of powder, preferably within the first part, to produce the second part of complementary shape. - Casting: machining of a first part, then casting of a second part within the first part; the first part being made of an alloy having a melting point higher than the alloy forming the second part. - Welding: welding a first part and a second part. During welding, metallic bonds are formed at the interface between the two parts (different alloys) at a predetermined temperature or temperature profile. Preferably, the welding is carried out (1) by machining at least two parts, preferably of complementary shapes, so as to obtain a controlled clearance between the assembled parts (advantageously a clearance of at least 0.02 mm, preferably at least 0.05 mm, preferably less than 1 mm, advantageously between 0.02 and 0.5 mm); then (2) by uniform heating of the parts (welding). This gap between the parts is filled during assembly, by the molten alloy(s). Advantageously, the alloys have different melting points with a difference of at least 50°C, preferably a difference between 50°C and 500°C. For example, in particular in the case of red gold and white gold parts, the welding temperature is advantageously between 950 and 980°C. The uniform heating of the parts (welding) can be carried out in a furnace (advantageously between 800°C and 1000°C) and include a rise in temperature, then a plateau at the welding temperature, then a fall in temperature. The rise and / or fall in temperature can be carried out between 50 and 150°C / minute, advantageously between 90 and 110°C / minute, more advantageously at 100°C / minute.The welding temperature hold consists of maintaining the parts at this temperature, advantageously for 1 to 20 minutes, more advantageously between 3 and 10 minutes, preferably for 5 minutes. This hold is of relatively short duration in order to control the heating and melting of the alloys. Advantageously, the welding is carried out at a temperature at least 50°C lower than the melting temperature of the metallic material with the highest melting point. Advantageously, only the metallic material with the lowest melting point melts during welding. Advantageously, the welding temperature is maintained for at least one minute, preferably at least 2 minutes, more preferably at least 3 minutes. - Ultrasonic welding: ultrasound makes it possible to generate metallic bonds between two identical or different alloys. Ultrasonic welding is advantageously carried out (1) by machining at least two parts, preferably of complementary shapes, so as to obtain a controlled clearance between the assembled parts (advantageously a clearance of at least 0.02 mm, preferably at least 0.05 mm, preferably less than 1 mm, advantageously between 0.02 and 0.5 mm); then (2) by assembling the parts (ultrasonic welding). This clearance between the parts is filled during assembly by ultrasonic welding. - Three-dimensional printing. - Shrinking (for example by heating and / or cooling the parts to be assembled) of a first (shrink-fit) part and a second (shrink-fit) part, for example shrink-fitting of a first (shrink-fit) part consisting of a gold bar 10.01 mm in diameter and having a thermal expansion coefficient of 14.106 K 1 and a second part (shrink-fit) comprising a hole 10 mm in diameter, the first and second parts being in the same alloy and having during shrink-fitting a temperature difference of the order of (0.01 / (14.106 x 10.01) = 71.36, i.e. a difference of approximately 75°C).

[0012] These techniques (chasing, powder sintering, melting, welding, ultrasonic welding, three-dimensional printing and shrink fitting) can be used to assemble at least two rooms.

[0013] The block is said to be “composite” in that it is made up of several different materials, in particular several different metallic materials. The metallic materials forming the composite block are alloys, more particularly gold, silver, or platinum alloys. Thus, in the present description of the invention, the terms “metallic material” and “alloy” designate an alloy chosen from the group consisting of gold alloys, silver alloys, and platinum alloys.

[0014] According to the invention, a hollow region is a three-dimensional portion of a part, obtained, for example, by hollowing out the metallic material constituting the part. The non-hollowed metallic material constitutes a solid region. The solid and hollow regions may have various shapes, for example a cylinder, a cube, a rectangular parallelepiped or not, a sphere or a portion of a sphere, or a combination of these shapes such as a clover, preferably a four-leaf clover. Advantageously, the piece of jewelry or timepiece is in the shape of a clover, preferably a four-leaf clover.

[0015] For a cylindrical part, for example, the hollow regions may be, in particular, three-dimensional sectors. A sector is an angular fraction of a cylinder. It is the combination of a two-dimensional angular sector (a face delimited by two half-lines starting from the main axis of the cylinder, therefore transverse to said axis) and a third dimension which is parallel to the axis of the cylinder. It therefore takes the form of a portion of a cylinder, in three dimensions like a slice of cake, comprising a volume which extends in a direction parallel to the height of the cylinder, delimited by two transverse faces which are the corresponding angular sectors.

[0016] In practice, before assembling the parts together, the metal parts are positioned relative to each other so that their faces comprising the hollow region, generally their transverse faces, are opposite each other. The parts are positioned in a conformation such that the solid regions of one of the parts face the hollow regions of another part. The parts are then brought together and then assembled by inserting the solid regions of one of the parts into the hollow regions of another part.

[0017] The interlocking of the metal parts together forms a multi-material pattern comprising solid regions of the different metal materials in the structure of the composite block.

[0018] In particular, when the latter is formed by the assembly of cylindrical parts from which sectors have been removed, the multi-material pattern comprises an alternation of sectors of the different metallic materials along a circumference of the composite block.

[0019] This multi-material pattern is particularly visible on a cross-section of the composite block at the level of an overlapping region of the assembled parts, that is to say in a plane perpendicular to the axis of the composite block passing through the solid regions of the different assembled parts. For example, a regular or irregular checkerboard pattern can be observed when the solid regions are cubes, or an alternation of the angular sectors of the different metallic materials, arranged like slices of cake around the axis of the block, when the parts are cylindrical.

[0020] This multi-material pattern is the starting point for the manufacture of a piece of jewelry or watchmaking, a process for which is part of the invention and is described in the remainder of this text.

[0021] It is specified that the composite block can be formed by assembling two pieces, three pieces, four pieces or even more.

[0022] For example, when the composite block is formed of three parts, the parts are all three assembled by inserting the solid regions of the parts into hollow regions of the other parts, by at least partial shape complementarity between said solid regions and said hollow regions. The parts intended to be assembled do not all comprise a hollow region. For example, it is possible to create a hollow region (for example by removing material) of a small cylindrical volume in a first cylindrical part, then to insert therein a second cylindrical part of a shape complementary to the small cylindrical volume removed. In this case, only the first cylindrical part comprises a hollow region (for example following removal of material).

[0023] In this regard, "shape complementarity" means that the solid regions of the parts fill, after assembly, substantially the entire volume of the hollow regions of said parts. For example, a hollow region of a first part can be filled by a solid region of a single other part, or by the solid regions of two other parts.

[0024] Preferably, all the hollow regions of the parts are filled by shape complementarity, after assembly, by at least one solid region of at least one other part. Thus, an assembly of two parts leads to a filling of all the hollow regions of one part by the corresponding solid regions of the other part. An assembly of three parts leads to a filling of all the hollow regions of at least one of the three parts, preferably of each of the three parts, by the corresponding solid regions of the other parts, each hollow region of a part being filled by a solid region of another part or by a solid region of each of the two other parts.

[0025] Furthermore, in the context of jewelry or watchmaking, it is particularly in interesting to provide metallic materials of different colors. Therefore, the alternation of the sectors of the parts results in an alternation of several colors along the circumference of the composite block. When the parts include several materials of different colors, for example two materials for each of the parts, the composite block consists of an alternation of the four colors along its circumference.

[0026] The composite block is not, however, limited to the assembly of cylindrical parts. Parts of square or hexagonal section, for example, of greater or lesser thickness (or height) compared to the other dimensions of the part, are also suitable within the scope of the invention.

[0027] Similarly, the invention is not limited to specific metals. Coins of all types of metals are also suitable, advantageously of different colors in order to be able to distinguish the alternation of the different metals. Preferably, the coins are made of precious or semi-precious metals, for example gold, silver, platinum, or mixtures thereof.

[0028] According to other aspects, the manufacturing method according to the invention has the following different characteristics taken alone or according to their technically possible combinations: - step a) of forming at least one part having a hollow region is carried out by removing at least one region of material in at least two of the parts, called first part and second part; and step b) of assembly is carried out by inserting at least one solid region of the first part into at least one hollow region of the second part, said solid region(s) at least partially filling said hollow region(s) by shape complementarity; - step a) of forming at least one part having a hollow region is carried out, advantageously by shrinkage, in each of the parts which are subsequently assembled and fixed together, so as to form at least one hollow region bordered partially or totally by at least one solid region of each of the parts; and step b) of assembly is carried out by inserting at least one solid region of each of the parts into at least one hollow region of each of the parts, said solid regions at least partially filling said hollow regions by shape complementarity; - at least one solid region of at least one of the parts and at least one hollow region of at least one other of said parts have complementary shapes in pairs, so that after insertion, the solid region fills the hollow region by shape complementarity; - step b) is carried out by assembly (chasing, powder sintering, casting, welding, ultrasonic welding, three-dimensional printing or shrink fitting), advantageously by welding at least one solid region of one of the parts with an adjacent solid region of another of the parts; - at least two of the pieces are in the form of cylindrical bars (or three-dimensional shapes, for example tokens), the hollow regions of which are hollow sectors which extend along a height of the cylindrical bars, bordered at least in part by solid sectors constituting the solid regions; - at least one of the parts is composed of at least two different metallic materials, and at least one other of the parts is composed of at least one metallic material different from those of said one of the parts, the composite block obtained being composed of at least three different metallic materials; - the metal materials of the parts are of different colors.

[0029] The invention also relates to a composite block made of gold, silver, or platinum alloy, formed by assembling at least two parts made of different metallic materials chosen from said alloy, one of the parts comprising at least one hollow region (advantageously obtained by forming a hollow region, for example by removing a corresponding region of material); at least one solid region of at least one of the parts being inserted into a hollow region of at least one other of said parts, the solid region(s) inserted into a hollow region at least partially fill said hollow region by shape complementarity, and in which the parts are assembled together using a technique chosen from among chasing, powder sintering, casting, welding, ultrasonic welding, three-dimensional printing and shrink fitting.

[0030] According to other aspects, the composite block according to the invention has the following different characteristics taken alone or according to their technically possible combinations: - at least two of the parts comprise at least one hollow region (for example obtained by removing a corresponding region of material), and at least one solid region; at least one solid region of the first part being inserted into a hollow region of the second part, said solid region(s) at least partially filling said hollow region(s) by shape complementarity; - each of the parts comprises at least one hollow region (for example obtained by removing a corresponding region of material), and at least one solid region; at least one solid region of each of the parts being inserted into a hollow region of each of the parts, said solid regions at least partially filling said hollow regions by shape complementarity; - at least one solid sector of at least one of the parts and at least one hollow sector of at least one other of said parts have complementary shapes in pairs, so that after insertion, the hollow sector fills the hollow sector by complementarity of form; - the parts are assembled together by welding at least one solid region of one of the parts with an adjacent solid region of another of the parts; - the parts are in the form of cylindrical bars, the hollow regions of which are hollow sectors which extend along a height of the cylindrical bars, bordered at least in part by solid sectors constituting the solid regions; - at least one of the parts is composed of at least two different metallic materials, and at least one other part is composed of at least one metallic material different from those of said one of the parts, the composite block being composed of at least three different metallic materials; - the metal materials of the parts are of different colors.

[0031] The present invention also relates to a method of manufacturing a piece of jewelry or timepiece.

[0032] According to one embodiment, the formation of the hollow region (for example by material removal, in particular by subtractive manufacturing) is carried out by one of the following techniques: machining, preferably computer numerical control machining, die-sinking EDM, laser cutting, water jet cutting, wire EDM cutting, scroll saw cutting, stamping cutting or striking tool. The formation of the hollow region can also be carried out by one of the following techniques: additive manufacturing (for example three-dimensional printing), lost wax casting, continuous casting, electroforming...

[0033] According to one embodiment, the method may further comprise, after the formation of the hollow region (for example by removal of material, in particular by subtractive manufacturing, or by addition of material, in particular by additive manufacturing) a step of finishing the piece of jewelry or watchmaking, chosen from: guilloché, polishing, satin finishing, etc. In the case of subtractive manufacturing, the finishing step may also include at least one of the following techniques: texturing, brushing, and sandblasting / microblasting. Additive manufacturing may be carried out by one of the following techniques: addition of metal elements (in particular precious metals) by three-dimensional additive manufacturing, brazing, soldering or rhodium plating, addition of non-metallic elements, such as enameling, lacquer, stone setting, etc.

[0034] The invention also relates to a piece of jewelry or timepiece, comprising a composite block as described above, for example treated by subtractive manufacturing according to the preceding method, comprising on at least one transverse face a pattern formed by removal of material from the composite block from said transverse face, in an overlap region which has solid regions of at least two pieces.

[0035] The method of manufacturing a piece of jewelry or watchmaking may include the following steps: - supply of a composite block as described above, or obtained according to the manufacturing process described above, - processing of the composite block by subtractive manufacturing, comprising a step of forming a pattern by removing material from a transverse face of the composite block, in an overlap region which has solid regions of at least two of the parts, to obtain the piece of jewelry or watchmaking.

[0036] The removal of material by subtractive manufacturing is advantageously carried out by one of the following techniques: machining, preferably computer numerical control machining, die-sinking EDM, laser cutting, water jet cutting, wire EDM cutting, scroll saw cutting, stamping cutting or striking tool.

[0037] The method of manufacturing a piece of jewelry or timepiece may advantageously comprise, after the removal of material by subtractive manufacturing, a step of finishing the piece of jewelry or timepiece, advantageously by guilloché.

[0038] Preferably, the pattern of the piece of jewelry or timepiece comprises a finish chosen from: a guilloche, polishing, satin finishing, etc. The piece of jewelry or timepiece preferably comprises a pattern in the shape of a clover and comprising a guilloche finish. Description of figures

[0039] Other advantages and characteristics of the invention will appear on reading the following description given by way of illustrative and non-limiting example, with reference to the following appended figures:

[0040] [Fig. 1] [Fig. 1] is a perspective view of the first part made of metallic material according to a first embodiment, which is in the form of a four-leaf clover, comprising several hollow regions advantageously obtained after removal of several regions, called “sectors”.

[0041] [Fig.2] [Fig.2] is a perspective view of the second piece of material metal according to a first embodiment, which is in the form of a four-leaf clover, comprising several hollow regions advantageously obtained after removal of several sectors.

[0042] [Fig.3] [Fig.3] is a perspective view of a composite block according to the first embodiment, formed by assembling the first and second parts of figures 1 and 2.

[0043] [Fig.4] [Fig.4] is a perspective view of a piece of jewelry or watchmaking, obtained by machining a section of the composite block of [Fig.3] to form a guilloché.

[0044] [Fig.5] [Fig.5] is a perspective view of the first piece of metal material metal according to a second embodiment, which is in the form of a cylinder, comprising several hollow regions advantageously obtained after removal of several regions, called “sectors”.

[0045] [Fig.6] [Fig.6] is a perspective view of the second piece of metal material metal according to a second embodiment, which is in the form of a cylinder, comprising several hollow regions advantageously obtained after removal of several sectors.

[0046] [Fig.7] [Fig.7] is a side view of the first and second cylindrical pieces figures 5 and 6 positioned opposite each other along their respective axes.

[0047] [Fig.8] [Fig.8] is a perspective view of a composite block according to the second embodiment, formed by assembling the first and second parts of figures 5 and 6.

[0048] [Fig.9] [Fig.9] is a front view of a cross-section of the composite block of [Fig.8], which illustrates an alternation of the solid sectors of the metallic materials of the first and second constituent parts of the composite block.

[0049] [Fig. 10] [Fig. 10] is a perspective view of the composite block of [Fig.8], one transverse face of which has been machined to form a piece of jewelry or watchmaking.

[0050] [Fig. 11] [Fig. 11] is a perspective view of the piece of jewelry or watchmaking in [Fig. 10], after guilloché work has been carried out.

[0051] [Fig. 12] [Fig. 12] is an illustration of the assembly of the first and second pieces (clover-shaped tokens) to form a composite block.

[0052] [Fig. 13] [Fig. 13] in views of a composite block, from left to right: rear face, side, front face in perspective and rear face in perspective.

[0053] Detailed description of embodiments of the invention

[0054] The invention relates to a method for manufacturing a composite block by assembling two parts made of different metallic materials. This method makes it possible to obtain a composite block which is perfectly suitable, as a starting material, for the manufacture of a piece of jewelry or watchmaking.

[0055] The materials may differ in particular by the nature of their constituent elements and / or by the relative contents of their constituent elements. This difference in materials may in particular result in a difference in color, so as to obtain a composite block and then a multi-colored piece of jewelry or timepiece, for example two-color, three-color, or four-color.

[0056] The constituent materials of the parts comprise at least one precious metal chosen among an alloy of gold, silver, or platinum.

[0057] A first embodiment of such a method according to the invention is illustrated in detail in Figures 1 to 4.

[0058] According to this first embodiment, with reference to figures 1 and 2, the first and second parts 1, 2 made of metallic materials are in the form of four-leaf clovers, in other words a structure with four lobes of similar size, of revolution along an axis 3. The first and second parts 1, 2 have a width Lg (or diameter) perpendicular to the axis 3 and a height H parallel to the axis 3.

[0059] This clover shape can be obtained for example by machining a cylinder.

[0060] In accordance with the method of the invention, hollow regions are produced, advantageously by removing at least one region of material by hollowing out the first and second parts 1, 2. In the first embodiment, the regions of material are three-dimensional sectors, more simply called "sectors". The production of the hollow regions, advantageously by removing material, thus makes it possible to form, on each part, at least one hollow sector 5 which is bordered by at least one solid sector 6. The parts shown in Figures 1 and 2 respectively are obtained.

[0061] In Figures 1 and 2, the hollow sectors 5 extend along the width Lg of each part 1, 2, from the axis 3 to the periphery 4 (or circumference) of the part. They form three-dimensional parts of substantially triangular section (or profile).

[0062] The hollow sectors 5 are formed, advantageously hollowed out by material removal, in the height H of the part, that is to say in a direction parallel to the axis 3. Advantageously, the formation of the hollow region (advantageously by material removal) is not carried out in the entire height H of the part, so as to leave a portion of solid part 7 at the end of said part. This makes it possible to subsequently form a composite block 20 whose transverse faces 21 are solid. These solid faces 21 serve as an axial stop during the insertion of the parts 1, 2 into each other, thus facilitating the manufacture of the composite block 20 and making the latter more stable before the parts are joined together, these different steps being described in the remainder of this text.

[0063] It is specified that the depth of the hollow region (advantageously formed by removal of material) can vary from one sector to another, so that the hollow sectors 5 obtained can have different depths P, in a direction parallel to the axis 3. In this case, the portion of solid part 7 in the shape of a clover at the end of said part itself has a height which varies along its circumference.

[0064] Furthermore, the depth of the hollow region (advantageously formed by material removal) can vary, within the same sector, according to the radius between the axis 3 and the periphery 4 of the part 1, 2, as well as according to the angular position within the sector. In other words, the sectors can be hollowed out irregularly. The sectors hollow sectors 5 obtained can thus each have a variable depth P between the axis 3 and the periphery 4 of the part and / or according to the angular position within the hollow sector 5. This is visible in figures 1 and 2, where the hollow sectors 5 have a profile 8 in the shape of a “U” whose bottom is rounded and the ends are flared. The solid sectors 6, which border the hollow sectors 5 by separating them from each other, have a profile 9 in the shape of a “U” whose bottom is straight, the latter being cut out of the material to obtain an exposed face 10 of the part 1, 2 which is flat.

[0065] The axis 3 of the first part 1 is also hollowed out, thus forming an axis called a “hollow axis”. On the other hand, the axis of the second part 2 is not hollowed out, and remains solid.

[0066] Advantageously, the exposed face 10 of each of the parts 1, 2 has a star-shaped structure, the branches of which are the solid sectors 6 which border the hollow sectors 5.

[0067] As illustrated in Figures 1 to 3, the solid sectors 6 of the first part 1 and the hollow sectors 5 of the second part 2 have complementary shapes in pairs. Similarly, the solid sectors 6 of the second part 2 and the hollow sectors 5 of the first part 1 have complementary shapes in pairs. This complementarity of the solid and hollow sectors of the two parts allows them to be assembled by insertion, to obtain the assembly of [Fig. 3], called “composite block” 20.

[0068] When the depth of the hollow region (advantageously formed by removal of material) varies within the hollow sectors 5 of the parts 1, 2, whether according to the radius or according to the angular position, these variations are complementary between the two parts, in order to allow the insertion of the solid sectors 6 of one of the parts into the hollow sectors 5 of the other part during their assembly.

[0069] Advantageously, the hollow axis 3 of the first part 1 has a shape complementary to that of the solid axis 3 of the second part 2. During the step of assembling the parts 1, 2, the solid shaft of the second part is thus inserted into the hollow axis of the first part.

[0070] With reference to [Fig.3], the composite block 20 is composed of two pieces nested one inside the other, the first piece 1 being positioned on the second piece 2 in the perspective view shown.

[0071] In [Fig. 3], we can clearly see a sinusoidal-shaped border 21 which winds along the periphery 22 of the composite block 20, at the junction of the first and second parts 1, 2, resulting from the complementarity of said parts.

[0072] The parts 1, 2 are then secured together in order to ensure the structural cohesion of the composite block 20.

[0073] Preferably, the assembly of the parts to each other is carried out by welding. In this case, the solid sectors 6 of the first part 1 are preferably welded with the 6 adjacent solid sectors of the second part 2.

[0074] Advantageously, the shaft 3 of the first part 1 can also be fixed with the shaft of the first part 2, in order to further reinforce the structural cohesion of the composite block. The fixing of the shafts 3 is preferably carried out by welding.

[0075] From this composite block 20, the invention proposes a method for manufacturing a piece of jewelry or timepiece 30, by treating said treatment of the composite block 20 by subtractive manufacturing.

[0076] In a manner known per se, subtractive manufacturing makes it possible to transform a block of solid material by progressive removal of material in order to arrive at the desired shape of a part.

[0077] In the context of the invention, the treatment of the composite block 20 by subtractive manufacturing comprises a step consisting of hollowing out the metallic material in the height Hb of the composite block 20 from at least one transverse face 23 thereof, or from the two transverse faces 23, 24, in order to obtain the desired piece of jewelry or timepiece 30, illustrated in [Fig.4].

[0078] The transverse face 23 to be hollowed out may be a free face of the composite block, i.e. the back of one or other of the first and second parts 1, 2 forming the composite block, or may be the result of a prior cutting of the composite block. It is for example possible to cut a section at the end of the composite block to remove it, and to treat the new transverse face made free.

[0079] In all cases, the composite block 20 is hollowed out at least up to a so-called overlap region 25, at which there is an alternation of the first and second parts 1, 2, more precisely of their solid angular sectors, along the periphery 22 of the composite block.

[0080] This overlap region 24 is thus delimited, in the height Hb of the composite block 20, by the border 21.

[0081] By removing material up to the overlap region 25, a pattern 26 is formed which is characteristic of the piece of jewelry or timepiece 30 which is to be manufactured. In [Fig. 4], the pattern 26 of the piece 30 is a low four-leaf clover, obtained by hollowing out the two transverse faces 23, 24 up to the overlap region 25.

[0082] The formation of the hollow region (advantageously by material removal) can be carried out by any known manufacturing technique, in particular by molding or by subtractive manufacturing. Preferably, the subtractive manufacturing technique is chosen by one of the following techniques: machining, die-sinking EDM, laser cutting, water jet cutting, wire EDM cutting, scroll saw cutting, stamping cutting or striking tool. The formation of the hollow region can also be carried out by one of the following techniques: manufacturing additive (for example, three-dimensional printing, lost wax casting, continuous casting, electroforming, etc.) When machining is chosen, it is preferably computer numerical control (CMC) machining.

[0083] Preferably, after the formation of the hollow region (advantageously formed by removal of material by subtractive manufacturing), a step of terminating the piece of jewelry or timepiece 30 is carried out. This step makes it possible to form a termination on the pattern 26 previously produced in order to confer a particular aesthetic appearance to said pattern 26, more specifically visual characteristics consistent with the achievements of the luxury industry.

[0084] The finishing technique is preferably at least one of the following techniques: guilloché, polishing, satin finishing, etc. In the case of subtractive manufacturing, the finishing step may also include at least one of the following techniques: texturing, brushing, and sandblasting / microblasting. Additive manufacturing may be carried out by one of the following techniques: adding metal elements (particularly precious metals) by three-dimensional additive manufacturing, brazing, soldering or rhodium plating, adding non-metallic elements, such as enameling, lacquering, stone setting, etc.

[0085] In the present case, a guilloche pattern 26 was made in the shape of a clover, to obtain a clover provided with a guilloche type termination 31, as shown in [Fig.4],

[0086] A second embodiment of the method for manufacturing a composite block according to the invention is illustrated in detail in Figures 9 to 10.

[0087] According to this second embodiment, the first and second parts 1, 2 made of metallic materials are in the form of cylindrical bars of revolution along an axis 3. The first and second parts 1, 2 have a width Lg (the diameter of the cylinder) perpendicular to the axis 3 and a height H parallel to the axis 3.

[0088] At least one sector is removed from each of the first and second parts 1, 2, to form, on each part, at least one hollow sector 5 which is bordered by at least one solid sector 6. The parts shown in Figures 5 and 6 respectively are thus obtained.

[0089] In Figures 5 and 6, the hollow sectors 5 extend, along the width Lg of each cylindrical part 1, 2, from the axis to the periphery 4 (the circumference of the cylinder) of the part. They thus form three-dimensional parts of substantially triangular profile.

[0090] As in the case of the first embodiment, the hollow sectors 5 are formed, advantageously by removal of material, in the height H of the part, namely in a direction parallel to the axis 3, from the periphery 4 towards the axis 3 of the cylinder (a radius of the cylinder). Advantageously, the hollow region (advantageously formed by shrinkage) is not produced over the entire height H of the cylinder, but to a depth P, so as to leave a full cylinder portion 7 at the end of said cylinder.

[0091] During the manufacture of the cylindrical parts 1, 2 of figures 5 and 6, the hollow region (advantageously formed by removal of material) was produced in an identical manner for all the hollow sectors 5, in their height H and in their width Lg. All the hollow sectors 5 thus extend over almost the entire height of the cylinder, and have a bottom 11 in the shape of a “U”, adjoining the end portion left solid 7. They extend homogeneously over the entire radius of the cylinder, that is to say from the axis 3 to the circumference 4 of the cylinder.

[0092] The solid sectors 6, which border the hollow sectors 5 and separate them from each other, have an isosceles triangular section.

[0093] The axis 3 of the second cylindrical part 2 is also hollowed out. On the other hand, the axis of the first cylindrical part 1 is not hollowed out, and remains solid.

[0094] Advantageously, the exposed face 10 of each of the cylindrical parts 1, 2 has a star-shaped structure, the branches of which are the solid sectors 6 which border the hollow sectors 5.

[0095] As illustrated in Figures 5 to 7, the solid sectors 6 of the first part 1 and the hollow sectors 5 of the second part 2 have complementary shapes in pairs. Similarly, the solid sectors 6 of the second part 2 and the hollow sectors 5 of the first part 1 have complementary shapes in pairs. This complementarity of the solid and hollow sectors of the two parts allows them to be assembled by insertion, to obtain the composite block of [Fig.8].

[0096] Advantageously, the solid axis 3 of the first part 1 is inserted into the hollow axis 3 of the second part 2. For the purposes of the invention, the solid axis is considered to be a solid region and the hollow axis is considered to be a hollow region.

[0097] Prior to their assembly, the cylindrical parts 1, 2 are positioned facing each other, their transverse face being opposite, according to [Fig.7].

[0098] The parts 1, 2 are then brought together and assembled one inside the other so as to fit them together, in the direction of the arrows F. During assembly, the solid sectors 6 of one of the parts slide into the hollow sectors 5 of complementary shapes of the other part, until they come to abut against the solid cylinder portion 7.

[0099] With reference to [Fig.8], the composite block 20 is composed of the two parts 1, 2 nested one inside the other.

[0100] In a similar manner to the first embodiment, a sinusoidal-shaped border 21 is observed which winds along the periphery 22 of the composite block 20, at the junction of the first and second parts, resulting from the complementarity of said parts.

[0101] The parts 1, 2 are then joined together, preferably by welding, in order to ensure the structural cohesion of the composite block.

[0102] From this composite block 20, a piece of jewelry or timepiece 30 is manufactured by subtractive manufacturing.

[0103] To do this, the metallic material is hollowed out in the height Hb of the composite block 20 from a transverse face 23 thereof, or the two transverse faces 23, 24, in order to obtain the desired piece of jewelry or watchmaking.

[0104] The transverse face 23 to be hollowed out may be a free face of the composite cylinder, i.e. one of its two transverse faces 23, 24, or may be produced by cutting the composite cylinder. It is for example possible to cut a section at the end of the cylinder 20 to remove it, and to treat the new transverse face made free.

[0105] In all cases, the composite cylinder 20 is hollowed out at least up to the overlap region 25 delimited by the border 21, at the level of which there is an alternation of the first and second parts 1, 2, along the periphery 22 of the cylinder.

[0106] A hollow region (advantageously formed by removal of the material) homogeneous in depth from a solid transverse face 23 to the overlap region 25 leads to exposing said overlap region, a section 26 of which is shown in [Fig.9].

[0107] In this [Fig.9], we note the alternation, around the axis 3, of the two metallic materials of the two initial cylindrical parts 1, 2. The face is therefore bi-material. The material of the first metallic part is shown hatched, while the material of the second part is shown plain. If the metallic materials are of different colors, the face is bi-color. It can be tri-color, quadri-color, or more, depending on the number of different materials of the initial metallic parts 1, 2.

[0108] From the surface of [Fig.9], a pattern 26 characteristic of the piece of jewelry or watchmaking that one wishes to manufacture is formed by subtractive manufacturing. Such a pattern 26 is illustrated on the end of the cylinder of [Fig.9] as well as on [Fig. 10], the latter taking the form of a four-leaf clover.

[0109] A finishing step then makes it possible to produce a finishing, such as a guilloche 31, on the clover. The piece of jewelry or watchmaking obtained at the end of the process is shown in [Fig.l 1].

[0110] [Fig. 12] illustrates the assembly of the first 1 and second 2 pieces (clover-shaped tokens) to form a composite block.

[0111] [Fig. 13] illustrates a composite block (clover-shaped token), of which piece 1 has a rim. When assembling the pieces, piece 2 is inserted inside of part 1. In the case of assembly by welding, the rim is used in particular to limit an overflow of molten material. This rim can be part of the jewelry or watch part or only to limit an overflow of molten material, the rim is then removed during an operation subsequent to assembly.

Claims

Claims

1. A method of manufacturing a composite block (20) made of a gold, silver, or platinum alloy, the composite block being formed by assembling at least two parts made of different metallic materials chosen from said alloys, the method comprising the following steps: a) forming at least one part (1, 2) having a hollow region (5), advantageously by removing at least one region of material, b) assembling the parts (1, 2), by inserting at least one solid region (6) of at least one of the parts (1, 2) into a hollow region (5) of at least one other of said parts (1, 2), the solid region(s) (6) inserted into a hollow region (5) at least partially filling said hollow region (5) by shape complementarity, the assembly being carried out according to a technique chosen from among chasing, powder sintering, melting, welding, ultrasonic welding, three-dimensional printing and shrink fitting, c) obtaining a composite block.

2. Method according to claim 1, step a) being carried out by removing at least one region of material in at least two of the parts (1, 2), called first part (1) and second part (2), step b) of assembly being carried out by inserting at least one solid region (6) of the first part (1) into at least one hollow region (5) of the second part (1, 2), said solid region(s) (6) at least partly filling said hollow region(s) (5) by shape complementarity.

3. Method according to claim 1, step a) being carried out by shrinkage carried out in each of the parts (1, 2) which are subsequently assembled and fixed together, so as to form at least one hollow region (5) bordered partially or totally by at least one solid region (6), step b) of assembly being carried out by insertion of at least one solid region (6) of each of the parts (1, 2) in at least one hollow region (5) of each of the parts (1, 2), said solid regions (6) at least partly filling said hollow regions (5) by complementarity of shape.

4. A method according to any one of the preceding claims, wherein at least one solid region (6) of at least one of the parts (1, 2) and at least one hollow region (5) of at least one other of said parts (1, 2) present two by two complementary shapes, so that after insertion, the solid region (6) fills the hollow region (5) by shape complementarity.

5. Method according to any one of the preceding claims, in which step b) of assembling the parts (1, 2) together is carried out by welding at least one solid region (6) of one of the parts (1, 2) with an adjacent solid region (6) of another of the parts (1, 2).

6. A method according to claim 5, wherein the welding is carried out at a temperature at least 50°C lower than the melting temperature of the higher melting metallic material.

7. Method according to claim 6, wherein the welding temperature is maintained for at least one minute, preferably at least 2 minutes, more preferably at least 3 minutes.

8. Method according to any one of the preceding claims, in which at least two of the parts (1, 2) are in the form of cylindrical bars, the hollow regions (5) of which are hollow sectors which extend along a height of the cylindrical bars, bordered at least in part by solid sectors (6) constituting the solid regions (6).

9. Method according to any one of the preceding claims, in which at least one of the parts (1, 2) is composed of at least two different metallic materials, and at least one other of the parts (1, 2) is composed of at least one metallic material different from those of said one of the parts (1, 2), the composite block (20) obtained being composed of at least three different metallic materials.

10. A method according to any preceding claim, wherein the metallic materials of the parts (1,2) are of different colors.

11. Composite block (20) made of gold, silver, or platinum alloy, formed by assembling at least two parts (1, 2) made of different metallic materials chosen from said alloy, one of the parts (1, 2) comprising at least one hollow region (5), at least one solid region (6) of at least one of the parts (1, 2) being inserted into a hollow region (5) of at least one other of said parts (1, 2), the solid region(s) (6) inserted into a hollow region (5) at least partly filling said hollow region (5) by shape complementarity, and in which the parts (1, 2) are assembled together according to a technique chosen from among chasing, powder sintering, casting, welding, ultrasonic welding, three-dimensional printing and shrink fitting.

12. Composite block (20) according to claim 11, wherein at least two of the parts (1, 2) comprise at least one hollow region (5) and at least one solid region (6), at least one solid region (6) of the first part (1) being inserted into a hollow region (5) of the second part (1, 2), said solid region(s) (6) at least partly filling said hollow region(s) (5) by shape complementarity.

13. Composite block (20) according to claim 11, wherein each of the parts (1, 2) comprises at least one hollow region (5), advantageously obtained by removing a corresponding region of material, and at least one solid region (6), at least one solid region (6) of each of the parts (1, 2) being inserted into a hollow region (5) of each of the parts (1, 2), said solid regions (6) at least partly filling said hollow regions (5) by shape complementarity.

14. Composite block (20) according to any one of claims 11 to 13, in which at least one solid sector (6) of at least one of the parts (1, 2) and at least one hollow sector (5) of at least one other of said parts (1, 2) have complementary shapes in pairs, so that after insertion, the hollow sector (5) fills the hollow sector (5) by shape complementarity.

15. Composite block (20) according to one of claims 11 to 14, in which the parts (1, 2) are assembled together by welding at least one solid region (6) of one of the parts (1, 2) with an adjacent solid region (6) of another of the parts (1, 2).

16. Composite block (20) according to one of claims 11 to 15, in which the parts (1, 2) are in the form of cylindrical bars, the hollow regions (5) of which are hollow sectors which extend along a height of the cylindrical bars, bordered at least in part by solid sectors (6) constituting the solid regions (6).

17. Composite block (20) according to one of claims 11 to 16, in which at least one of the parts (1, 2) is composed of at least two different metallic materials, and at least one other part (1, 2) is composed of at least one metallic material different from those of said one of the parts (1, 2), the composite block (20) being composed of at least three different metallic materials.

18. Composite block (20) according to any one of claims 11 to 17, wherein the metallic materials of the parts (1,2) are of different colors.

19. A method of manufacturing a piece of jewelry or timepiece (30), comprising the following steps: - providing a composite block (20) according to one of claims 11 to 18, or obtained by a manufacturing method according to one of claims 1 to 10, - processing the composite block (20) by subtractive manufacturing, comprising a step of forming a pattern (26) by removing material from a transverse face (10) of the composite block (20), in an overlap region (25) which has solid regions (6) of at least two of the parts (1, 2), to obtain the piece of jewelry or timepiece (30).

20. The method of claim 19, wherein the removal of material by subtractive manufacturing is performed by one of the following techniques: machining, preferably computer numerical control machining, die-sinking EDM, laser cutting, water jet cutting, wire EDM cutting, scroll saw cutting, stamping cutting or striking tool.

21. Method according to claim 19 or claim 20, further comprising, after the removal of material by subtractive manufacturing, a step of finishing the piece of jewelry or timepiece (30), by guilloché.

22. Piece of jewelry or timepiece (30), comprising a composite block (20) according to one of claims 11 to 18, treated by subtractive manufacturing according to the method of one of claims 19 to 21, comprising on at least one transverse face a pattern (26) formed by removal of material from the composite block (20) from said transverse face, in an overlap region (25) which has solid regions (6) of at least two pieces (1, 2).

23. A piece of jewelry or timepiece (30) according to claim 22, wherein the pattern (26) is in the shape of a clover and includes a guilloche termination.

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