Method for manufacturing a hand of a timepiece having a circular cross-section

Abstract

To provide a hand manufactured according to a method for manufacturing a monolithically molded timepiece hand by means of laser light.SOLUTION: A method for manufacturing a hand 20 of a timepiece having a body with a circular cross-section molded monolithically comprises: a first step of obtaining a monolithically molded component made of a prescribed material; a second step of rotating the monolithically molded component: a third step of emitting a first modulation of laser light in power, geometry and time; a fourth step of exposing a first portion of the at least one monolithically molded component to the first modulation of the laser light so as to form at least a first volume with a circular cross-section having a length L1 and a mean diameter D1; a fifth step of emitting a second modulation of the laser light in power, geometry and time; and a sixth step of exposing a second portion of the at least one monolithically molded component to the second modulation of the laser light so as to form at least a second volume.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The field of the present invention relates to the field of manufacturing methods for timepieces, and more particularly to the field of hands of timepieces with a circular cross-section.

Background Art

[0002] Hands generally have two dimensions and are flat, and are usually obtained by a hand manufacturing method consisting of cutting a metal sheet.

[0003] To assemble the hand on the movement and then fit it onto a rod passing through the dial, a hole is formed in the hand. Currently, a laser method can be used to cut the sheet.

[0004] This manufacturing method is easy to implement but is limited to creating two-dimensional hands. If it is desired to obtain a hand shape with a circular cross-section for aesthetic reasons, this method cannot be used. A circular cross-section means a hand with a rotational geometry in particular.

[0005] There is a laser rotation method consisting of rotating and machining an integrally formed body to form the axis or pivot of a timepiece movement and then cutting it using a laser beam. The body is held by a machine, the machine rotates the body at a predetermined speed, while irradiating the peripheral part of the body with a laser beam to cut the body. In this way, a part with a circular cross-section, such as a cylindrical or conical part, is obtained.

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, such a method cannot be used as it is because geometric defects appear on the hand, and it tends to form a hand with a circular cross-section. This is because the hand is thin and long, and the rotating operation may vibrate or displace the body, and as a result, laser machining impairs the accuracy to obtain a hand with a circular cross-section.

Means for Solving the Problems

[0007] The present invention attempts to solve all or part of these drawbacks by means of a hand made by a method for manufacturing the hands of an integrated timepiece using a laser beam.

[0008] Said method comprises - a first step consisting in obtaining an integrally formed part made of a predetermined material, extending along a longitudinal axis, - a second step consisting in rotating said integrally formed part, - a third step consisting in emitting a first modulation of said laser beam, for example in terms of output and / or geometry and / or time, - a fourth step consisting in exposing a first portion of said at least one integrally formed part to said first modulation of said laser beam so as to form at least a first volume having a circular cross-section with a length L1 and an average radius D1, for example cylindrical or conical, the ratio L1 / D1 being 10 or less, or even 5 or less, - a fifth step consisting in emitting a second modulation of said laser beam, for example in terms of output and / or geometry and / or time, - a sixth step consisting in exposing a second portion of said at least one integrally formed part to said second modulation of said laser beam so as to form at least a second volume having a circular cross-section with a length L2 and an average radius D2, for example cylindrical or conical, the ratio L2 / D2 being 10 or less, or even 5 or less which is worth noting.

[0009] Using this method, it is possible to manufacture a three-dimensional hand with a circular cross-section, in particular cylindrical or conical. This is because, initially, rotational machining is used to obtain the shape of a hand with a circular cross-section. However, by creating the hand with a portion having a length L and an average radius D such that the ratio L / D is 10 or less, or even 5 or less, the risk of vibration of the integrally formed part, and thus the risk of geometric defects, is avoided.

[0010] According to a particular embodiment of the invention, during the sixth step of the manufacturing method, a second portion adjacent to the first portion is selected.

[0011] According to a particular embodiment of the invention, the manufacturing method comprises an additional step of emitting a modulation of the laser light so as to form an additional volume, for example cylindrical or conical, with a circular cross-section having an L / D ratio of 10 or less, or even 5 or less, in order to obtain the required needle length, preferably exposing additional portions adjacent to one another.

[0012] According to a particular embodiment of the invention, a first portion is selected at the free end of the one-piece component.

[0013] According to a particular embodiment of the invention, at least a first volume with a circular cross-section has a smaller diameter than other volumes with a circular cross-section.

[0014] According to a particular embodiment of the invention, a volume with a circular cross-section forms a needle with an overall length Lt and an average radius Dt such that the Lt / Dt ratio is 10 or more, or even 100 or more.

[0015] According to a particular embodiment of the invention, the majority of the portions are machined so that the volume with a circular cross-section has a substantially the same length L.

[0016] According to a particular embodiment of the invention, the majority of the portions are machined so that the volume with a circular cross-section is cylindrical and has a substantially the same diameter D.

[0017] According to a particular embodiment of the invention, the majority of the portions are machined so that the volume with a circular cross-section forms a conical needle with a decreasing diameter.

[0018] According to certain embodiments of the present invention, the method comprises an additional step preceding the sixth step, and / or an additional exposure step of moving the integrally formed part to expose a second or additional part.

[0019] According to certain embodiments of the present invention, the method comprises a preceding step of, for example, using a laser to drill a hole in the integrally formed part into which a rod of a timepiece movement can be inserted.

[0020] According to certain embodiments of the present invention, a portion intended to have a volume with a circular cross-section is machined in advance for a hole having a diameter larger than that of other volumes with circular cross-sections.

[0021] According to certain embodiments of the present invention, the material preferably comprises metals such as steel, titanium, brass, aluminum, amorphous metal, etc. as a whole, or alloys of these metals, or composite ceramics or metal ceramics, or glass, sapphire, diamond, or ruby.

[0022] According to certain embodiments of the present invention, the method comprises an additional step of applying a layer of a phosphorescent material on a volume with a circular cross-section, and this volume with a circular cross-section preferably has a reduced diameter relative to other volumes with circular cross-sections.

[0023] The present invention also relates to a timepiece hand obtainable by the method according to the present invention, and the hand comprises an integrally formed body with a circular cross-section, such as a cylindrical or conical body.

[0024] According to certain embodiments of the present invention, the timepiece hand comprises a hole.

[0025] According to certain embodiments of the present invention, the timepiece hand preferably comprises metals such as steel, titanium, brass, aluminum, amorphous metal, etc. as a whole, or alloys of these metals, or composite ceramics or metal ceramics, or glass, sapphire, diamond, or ruby.

[0026] The present invention further relates to a timepiece comprising such a needle.

[0027] The objects, advantages, and features of the present invention will become apparent by reading several embodiments shown by way of non-limiting example only with reference to the accompanying drawings.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0029] The present invention relates to the use of a laser light source to form an integrally formed needle of a timepiece with a circular cross-section. In the embodiments described below, the shape of the needle is cylindrical.

[0030] According to the present invention, the manufacturing method 10 shown in FIGS. 1 to 5 comprises a plurality of steps.

[0031] In the first step 1, an integrally formed part 7 made of a predetermined material is obtained. For example, the predetermined material is preferably a metal such as steel, titanium, brass, aluminum, amorphous metal, etc. as a whole, or an alloy of these metals, or a composite ceramic or metal ceramic, or glass, sapphire, diamond, or ruby.

[0032] Preferably, a titanium alloy is selected for its lightness. Of course, other materials compatible with laser machining are assumed.

[0033] The integrally formed part 7 is preferably elongated along the longitudinal axis 17 and the length is at least equal to the required length of the needle. The integrally formed part 7 may be in an integrally formed shape or may have passed through the step of machining a stock piece. The integrally formed part 7 is preferably solid, that is, without cavities.

[0034] The second step 2 consists of the step of rotating the integrally formed part 7 to obtain the required shape, in this case a cylindrical shape with a circular cross-section. The integrally formed part 7 is machined by a laser machining device. The integrally formed part 7 is arranged on a rotary turning machine 9 that rotates the integrally formed part 7 about the longitudinal axis 17 of the integrally formed part 7 in order to machine the integrally formed part 7 at the peripheral edge of the integrally formed part 7.

[0035] In the third step 3, for example, a first modulation of the laser beam 8 in terms of output and / or geometry and / or time is emitted to cut a portion to the required diameter, for example using a laser device.

[0036] The fourth step 4 consists of the step of exposing a first portion 11 of the at least one integrally formed part 7 to the first modulation of the laser beam 8 so as to form at least a first cylindrical volume 14 having a length L1 and an average diameter D1. This is because when exposing at least the first portion 11 of the integrally formed part 7, the laser beam is modulated according to certain parameters so as to form the first cylindrical volume 14.

[0037] Select a partial length L1 such that the ratio L1 / D1 is 20 or less, or 10 or less, or even 5 or less. Using such a ratio avoids manufacturing defects that occur when the machining length is too long compared to the diameter of a part. This is because when the laser beam 8 moves along a part 11, a part 11 that is too long compared to the diameter D tends to bend, and as a result, the machining is no longer accurate and defects occur.

[0038] To machine the one-piece part 7, the one-piece part 7 may be further translatably movable relative to the laser device, and the laser device does not move. In a variant, the laser device is translatably movable, while the one-piece part 7 is movable only by rotation. The laser device and the one-piece part 7 may also both be translatably movable.

[0039] Next, in a fifth step 5, for example, a second modulation of the laser beam 8 is emitted in terms of output and / or geometry and / or time.

[0040] In a sixth step 6, at least a second part 12 of at least the one-piece part 7 is exposed to the second modulation of the laser beam 8 so as to form at least a second cylindrical volume 15 of length L2 and average radius D2, and the ratio L2 / D2 is 20 or less, preferably 10 or less, or even 5 or less.

[0041] The second part 12 is adjacent to the first part 11. In other words, the first part 11 and the second part 12 are continuous and are oriented around the same longitudinal axis 17. Moreover, it is also possible to configure the second modulation in the same way as the first modulation of the laser beam in terms of output and time.

[0042] In this embodiment, it is chosen to create cylindrical volumes of equal length, and as a result, L1 = L2 = L. In a modified embodiment, it is possible to machine cylindrical volumes of different lengths while maintaining a ratio L / D of 20 or less, or 10 or less, or even 5 or less for each cylindrical volume.

[0043] Expose an additional portion 13 of the one-piece part 7 so as to obtain a longer needle 20 in accordance with the total length Lt of the needle that is desired to be obtained.

[0044] Repeat the step of emitting the modulation of the laser beam 8 and exposing to the modulation of the laser beam 8 several times to obtain a plurality of successively adjacent cylindrical volumes 14, 15, 16.

[0045] In FIG. 2, machine a first portion 11 of length L to form a first cylindrical volume 14 of diameter D and length L at the end of the one-piece part 7 as shown in FIG. 3. Next, select a second portion 12 of length L adjacent to the first portion 11.

[0046] After laser machining the second portion 12, obtain a second cylindrical volume 15 that forms the end of the needle together with the first cylindrical volume 14 as shown in FIG. 4.

[0047] Next, select a third portion 13 of length L of the one-piece part 7 adjacent to the second cylindrical volume 15. Laser machine the third portion 13 to form a third cylindrical volume 16 of average diameter D and length L as shown in FIG. 5.

[0048] The needle 20 has, for example, a length of 15 mm to 20 mm, an average diameter of 0.2 mm to 0.5 mm at one end, and 0.3 mm to 0.6 mm at the other end.

[0049] Repeat the step of laser machining on additional adjacent portions until the total length Lt required for the needle 20 is obtained. As a result, the needle 20 comprises a one-piece cylindrical body.

[0050] Preferably, the obtained cylindrical volumes 14, 15, 16 have substantially the same diameter D, and as a result, the needle 20 has substantially the same diameter over its entire length Lt.

[0051] The successive cylindrical volumes 14, 15, 16 form the needle 20 of total length Lt, and the ratio Lt / D is preferably 10 or more, or even 100 or more.

[0052] The method may further comprise a subsequent step of surface finishing the adjacent volumes 14, 15, 16 in order to ensure that the shape and finish are substantially continuous. This step may be achieved by laser using milder parameters that create a surface with low roughness and make the interface between the two successive treated volumes invisible.

[0053] The method may further comprise a step of opening a hole 21 into which a rod can be inserted, which can be implemented before and after the step of laser machining.

[0054] Preferably beforehand, that is, before machining the cylindrical volume 24 containing the hole 21, a hole is created through a part of the one-piece component 7. As a result, the needles 20 of FIGS. 6 and 7 have a hole 21 for inserting the rod of the timepiece movement therein. By opening the hole 21 before laser machining, the risk of opening a hole in a needle that is too thin is avoided. If the width of the one-piece component 7 is wider, it is easier to hold the one-piece component 7 to open the hole 21.

[0055] Preferably, at least a part of the cylindrical volume 24 comprising the hole 21 has a larger diameter than the other cylindrical volumes, and in particular as a result, the hole 21 is quite deep to accommodate the rod, and as a result, the cylindrical volume 24 is sufficiently strong. The hole 21 can be opened by various machining techniques, in particular by laser.

[0056] In a specific variant embodiment shown in FIGS. 6 and 7, at least one cylindrical volume 22 at the end of the needle 20 has a reduced diameter. By reducing the diameter, a layer 23 of phosphorescent material can be deposited on the reduced cylindrical volume. This makes it possible, for example, to obtain an end of the needle 20 with the same diameter as the other cylindrical volumes 22. For this purpose, the diameter of the reduced cylindrical volume 22 is selected by the thickness of the layer 23 of phosphorescent material to be applied later.

[0057] One of the advantages of this method is to manufacture an integrally formed cylindrical timepiece hand 20 that is more rigid than a flat hand and further provides a specific aesthetic effect to the hand 20.

[0058] In addition, by the needle 20 further having a hole 21 directly formed in the integrally formed needle 20, it is possible to avoid attaching an additional part equipped with an incense box that has to be assembled on the needle 20 so that the needle 20 can be held by a rod of the timepiece movement. As a result, not only the difficulty in assembly but also the risk of disassembly are reduced.

[0059] Of course, the present invention is not limited to the embodiments described with reference to the drawings, and variant forms can be envisaged without departing from the scope of the present invention. As a result, this method can be used to form a hand with a conical shape by forming a conical portion whose diameters follow each other and decrease. Furthermore, it is possible to form a hand whose diameter changes with different volumes, provided that the different volumes have a circular cross-section.

Explanation of symbols

[0060] 1 First step 2 Second step 3 Third step 4 Fourth step 5 Fifth step 6 Sixth step 7 Integrally formed part 8 Laser beam 9 Rotary turning machine 10 Manufacturing method 11 The first part of the integrally formed component 12 The second part of the integrally formed component 13 An additional part of the integrally formed component, the third part of the integrally formed component 14 The first cylindrical volume 15 The second cylindrical volume 16 The third cylindrical volume 17 The longitudinal axis 20 The needle 21 The hole 22 At least one cylindrical volume at the end of the needle 23 The layer of phosphorescent material 24 The cylindrical volume containing the hole D, D1, D2 Mean radii L, L1, L2 Lengths

Claims

1. A method (10) for manufacturing the hands of a timepiece by integral molding with a laser beam, comprising: - a first step (1) of obtaining an integrally molded part (7) made of a predetermined material, extending along the longitudinal axis; - a second step (2) of rotating the integrally molded part (7); - a third step (3) of emitting the laser beam (8) with a first modulation related to output and / or geometry and / or time; - a fourth step (4) of exposing a first portion (11) included in a part of the at least one integrally molded part (7) to the laser beam (8) with the first modulation so as to form at least a first volume having a circular cross-section (14) with a length L １ and an average diameter D １ such that the ratio L １ / D １ is 20 or less; - a fifth step (5) of emitting the laser beam (8) with a second modulation related to output and / or geometry and / or time; - a sixth step (6) of exposing a second portion (12) included in the part of the at least one integrally molded part (7) to the laser beam (8) with the second modulation so as to form at least a second volume having a circular cross-section (15) with a length L ２ and an average diameter D ２ such that the ratio L ２ / D ２ is 20 or less; The manufacturing method (10) is characterized by comprising the above steps.

2. The manufacturing method (10) according to claim 1, wherein during the sixth step (6), the second portion (12) adjacent to the first portion (11) is selected.

3. To obtain the required needle length (20), the modulated laser light (8) is emitted to form a cylindrical or conical additional volume with a circular cross-section (16) where the ratio L / D is 20 or less, and an additional step of exposing an additional portion (13) adjacent to each other is provided, the manufacturing method (10) according to claim 1.

4. The manufacturing method (10) according to claim 1, wherein the first portion (11) is selected at the free end of the integrally formed part (7).

5. The manufacturing method (10) according to claim 1, wherein at least the first volume (14) with a circular cross-section has a shorter diameter than the second volume (15) with a circular cross-section.

6. The manufacturing method (10) according to claim 1, wherein the first volume (14) and the second volume (15) with circular cross-sections form a needle with an overall length Lt and an average diameter Dt, and the ratio Lt / Dt is 10 or more, or even 100 or more.

7. The manufacturing method (10) according to claim 1, wherein most of the portion is machined such that the first volume (14) and the second volume (15) with circular cross-sections have substantially the same length L.

8. The manufacturing method (10) according to claim 1, wherein most of the portion is machined such that the first volume (14) and the second volume (15) with circular cross-sections have substantially the same diameter D.

9. The manufacturing method (10) according to claim 1, wherein most of the portion is machined such that the first volume (14) and the second volume (15) with circular cross-sections have a decreasing diameter to form a conical needle.

10. The manufacturing method (10) according to claim 1, comprising an additional step preceding the sixth step (6) and / or an additional exposure step of moving the integrally formed part (7) to expose the second portion (12) or the additional portion (13).

11. The manufacturing method (10) according to claim 1, comprising a preceding step of opening, by means of a laser, a hole (21) into which a rod of a timepiece movement can be inserted in detail, into the integrally formed part (7). **Claim 12** The manufacturing method (10) according to claim 11, wherein the part of the integrally formed part (7) provided with the hole (21) is machined on the condition that it has a diameter larger than that of the first part (11) and the second part (12) with a circular cross section. **Claim 13** The manufacturing method (10) according to claim 1, wherein the material comprises, as a whole, a metal such as steel, titanium, brass, aluminum, amorphous metal, or an alloy of these metals, or a composite ceramic or a metal ceramic, or glass, sapphire, diamond, or ruby. **Claim 14** The manufacturing method (10) according to claim 1, comprising an additional step of applying a layer (23) of a phosphorescent material onto a volume with a circular cross section (22), wherein the volume with the circular cross section (22) has a reduced diameter.

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