阅读说明：本技术 用于钟表或首饰件的外部零件 (External part for a timepiece or piece of jewellery ) 是由 帕特里克·加斯曼 彼得·格施温德 艾伦·伯雷 于 2020-03-20 设计创作，主要内容包括：本发明涉及一种用于制造由穆拉诺玻璃制成的用于钟表或首饰件的外部零件的方法,所述方法包括以下步骤：提供由并排布置的玻璃棒(2),也被称为玻璃管,形成的材料；多循环热处理以使材料固结并且形成坯件；机械加工坯件以产生外部零件,所述方法的特征在于热处理包括第一循环(a),该第一循环(a)在于以在4℃/min和12℃/min之间的加热速率将材料从小于或等于100℃的温度加热至在450℃和650℃之间的温度,以便避免在坯件的制造期间气泡的形成。本发明还涉及具有很少或没有气泡的结构的用于钟表或首饰件的外部零件,特别是表壳。(The invention relates to a method for producing an external part made of Murano glass for a timepiece or piece of jewellery, comprising the following steps: providing a material formed by glass rods (2) arranged side by side, also called glass tubes; multi-cycle heat treatment to consolidate the material and form a blank; machining the blank to produce the external part, said method being characterized in that the heat treatment comprises a first cycle (a) consisting in heating the material from a temperature of less than or equal to 100 ℃ to a temperature of between 450 ℃ and 650 ℃ at a heating rate of between 4 ℃/min and 12 ℃/min, in order to avoid the formation of bubbles during the manufacture of the blank. The invention also relates to an external part for a timepiece or piece of jewellery, in particular a watch case, having a structure with few or no air bubbles.)

1. A method of manufacturing an external part made of muranol glass for a timepiece or piece of jewellery, comprising the steps of:

-providing a material formed by glass rods (2) arranged side by side, said glass rods (2) also being called glass tubes,

-a multi-cycle heat treatment to consolidate the material and form a blank,

-machining the blank to produce the outer part,

said method is characterized in that said thermal treatment comprises a first cycle (a) consisting in heating said material from a temperature lower than or equal to 100 ℃ to a temperature comprised between 450 ℃ and 650 ℃ at a heating rate comprised between 4 ℃/min and 12 ℃/min.

2. Method according to claim 1, characterized in that said first cycle (a) consists in heating said material from a temperature comprised between 500 ℃ and 600 ℃, preferably between 525 ℃ and 575 ℃, with a heating rate comprised between 5 ℃/min and 10 ℃/min, preferably between 6 ℃/min and 9 ℃/min.

3. The method according to claim 1 or 2, characterized in that said heat treatment comprises a second cycle (b) following said first cycle (a), consisting in stabilizing the movement of said glass rod (2), which second cycle (b) is carried out at a substantially constant temperature comprised between 450 ℃ and 650 ℃, preferably between 500 ℃ and 600 ℃, more preferably between 525 ℃ and 575 ℃, for a time comprised between 40 minutes and 140 minutes, preferably between 70 minutes and 110 minutes, more preferably between 80 minutes and 100 minutes.

4. The method according to claim 3, characterized in that the heat treatment comprises a third cycle (c) following the second cycle (b), consisting in consolidating the glass rods (2) together by heating the material to a temperature comprised between 650 ℃ and 900 ℃, preferably between 720 ℃ and 840 ℃, more preferably between 760 ℃ and 800 ℃, in a time comprised between 40 minutes and 140 minutes, preferably between 70 minutes and 110 minutes, more preferably between 80 minutes and 100 minutes.

5. The method according to claim 4, characterized in that said thermal treatment comprises a fourth cycle (d) following said third cycle (c), said fourth cycle (d) consisting in a temperature stabilization cycle reached in said third cycle (c), for a time comprised between 3 minutes and 17 minutes, preferably between 5 minutes and 15 minutes.

6. The method according to claim 5, characterized in that said heat treatment comprises a fifth cycle (e) following said fourth cycle (d), said fifth cycle (e) consisting in carrying out an expansion cycle at a temperature comprised between 350 ℃ and 650 ℃, preferably between 450 ℃ and 550 ℃, more preferably between 475 ℃ and 525 ℃, for several days, preferably between 1 day and 5 days, more preferably between 2 days and 4 days, before cooling said material to ambient temperature in order to form said blank.

7. An external part for a timepiece or piece of jewellery made of muranol glass, said part being formed by a part selected from the list comprising: middle part, bottom part, bezel, push-button, watch band chain, hand and dial sign, or formed by a plurality of parts selected from the list comprising: middle part, bottom, dial plate, bezel, button, watchband chain, pointer and dial mark.

8. External part according to claim 7, characterized in that it is a one-piece part made entirely of Muranol glass, forming a watch case (1) comprising a middle part (1a) and a dial (1 b).

9. External part according to claim 8, characterized in that the watch case has a circular or barrel shape.

10. Watch comprising an external part according to one of claims 7 to 9.

Technical Field

One of the typical properties of muranol glass is the colouring and decoration of the parts to be machined — millefori glass (millefiori). "thousand flowers glass" means "thousand flowers" and refers to a particular glass production technique. A mixture of glass rods of different colors is fused and partially covered with glass. The various colourations of glass rods are based on the use of colouring materials such as silver, gold, iron oxide (rust) and the like. After very careful processing, the fused glass rod is cut into disks to form what is known as Murrine.

In order to produce the external parts in horological mechanisms, the moeller stone must be machined precisely. By definition, glass parts are fragile. It has been observed that the standard process for producing moeller stone results in bubbles which make the material particularly brittle during machining, which leads to significant loss of material.

Document EP 0402685 discloses a manufacturing method and more specifically a machining method for dials made of mulanot glass. The document does not address the problem of bubbles.

Brief description of the invention

The present invention aims to solve the aforementioned drawbacks by proposing an optimized method for reducing or even eliminating the formation of bubbles during manufacture, so as to favour the mechanical working of the external parts and thus reduce the loss of material.

The invention also proposes an external part for a timepiece or piece of jewellery made of murano glass and having a structure with little or no air bubbles. More specifically, the invention relates to a watch case made of muranol glass in a single piece.

Brief Description of Drawings

The features and advantages of the present invention will become apparent upon reading the detailed description that follows with reference to fig. 1-4.

Fig. 1 schematically shows the steps of the manufacturing method consisting in assembling the glass rod in a mould in a known manner.

Fig. 2 schematically shows different temperature cycles of the method according to the invention.

Fig. 3a shows an outer part made of muranol glass according to the invention in one piece, formed by an intermediate part and a dial.

Fig. 3b shows a variant of fig. 3a with a middle part of circular shape.

Fig. 4 schematically shows a watch comprising the outer parts of fig. 3 b.

Detailed Description

The invention relates to an external part made of Murano glass for a timepiece or piece of jewellery, and to a manufacturing method for implementing the manufacturing of the part. In the field of horological mechanisms, the parts can be intermediate parts, bottom parts, bezels, buttons, bracelet strands, dials, hands and dial signs, etc. Preferably, it is a one-piece part made entirely of muranol glass, comprising an intermediate part 1a and a dial 1b to form a watch case 1 as shown in fig. 3a and 3 b. The dial as well as the middle part may assume any shape (circular, rectangular, square, barrel-shaped, etc.). As an example, in fig. 4 a watch is shown, comprising an integral part formed by an intermediate part and a dial, the intermediate part and the dial forming a watch case 1.

The manufacturing method comprises several steps, including a heat treatment step, which is more specifically an object of the present invention. The manufacturing method therefore comprises a step consisting in producing in a known manner a rod (also called rod) of polychrome glass 2 and in assembling them side by side in a mould 3 after cutting (figure 1). It then comprises a heat treatment step to form a consolidated blank, followed by a machining step to shape the blank.

The material formed from the glass rod is subjected to a heat treatment according to the invention, schematically shown in fig. 2, in order to form a blank. The heat treatment comprises five successive cycles (a) to (e) as follows:

- (a): this cycle consists in heating the material. This is a critical cycle to avoid bubble formation, and this cycle is more specifically the object of the present invention;

- (b): this is a hold cycle intended to stabilize the movement of the glass rod after the heating cycle;

- (c): this is another heating cycle intended to consolidate the glass rod;

- (d): this is a new holding cycle aimed at stabilizing the material;

- (e): this is an expansion cycle aimed at relaxing internal stresses inside the material.

The first cycle (a) is most critical for bubble formation because the glass rod moves under the action of heat. During this cycle, the material is placed in a furnace at a temperature less than or equal to 100 ℃ and preferably at ambient temperature. The cycle may be conducted in an uncontrolled atmosphere. Once the furnace is shut down, it is started so as to raise the temperature to a temperature comprised between 450 ℃ and 650 ℃, preferably between 500 ℃ and 600 ℃, more preferably between 525 ℃ and 575 ℃, with a heating rate comprised between 4 ℃/min and 12 ℃/min, preferably between 5 ℃/min and 10 ℃/min and more preferably between 6 ℃/min and 9 ℃/min.

The second, less critical cycle (b) is carried out at a substantially constant temperature corresponding to the highest temperature during heating in step (a). The cycle is carried out at a temperature comprised between 450 ℃ and 650 ℃, preferably between 500 ℃ and 600 ℃, more preferably between 525 ℃ and 575 ℃, for a time comprised between 40 minutes and 140 minutes, preferably between 70 minutes and 110 minutes, more preferably between 80 minutes and 100 minutes.

The third heating cycle (c) consists in raising the temperature from the plateau of the second cycle (b) to a temperature comprised between 650 ℃ and 900 ℃, preferably between 720 ℃ and 840 ℃, more preferably between 760 ℃ and 800 ℃ in a time comprised between 40 minutes and 140 minutes, preferably between 70 minutes and 110 minutes, more preferably between 80 minutes and 100 minutes.

The fourth cycle (d) is carried out at a substantially constant temperature corresponding to the highest temperature reached during the third cycle (c), i.e. between 650 ℃ and 900 ℃, preferably between 720 ℃ and 840 ℃, more preferably between 760 ℃ and 800 ℃, for a time comprised between 3 minutes and 17 minutes, preferably between 5 minutes and 15 minutes.

The fifth cycle (e) consists in placing the material in a second oven, called the expansion oven, after the fourth cycle (d). Typically, the transfer is completed in about one minute. The cycle may be carried out in an uncontrolled atmosphere at a temperature comprised between 350 ℃ and 650 ℃, preferably between 450 ℃ and 550 ℃, more preferably between 475 ℃ and 525 ℃, for several days, preferably between 1 day and 5 days, more preferably between 2 days and 4 days. Next, the material is cooled to ambient temperature and a blank is formed.

The blanks resulting from the heat treatment form what is known as moeller stones, which are machined to produce the outer part. Typically, the blank takes the form of a disc having a thickness of about 1 cm. The machining may be accomplished, for example, by diamond grinding. In the case of watch cases, the hands, glass and push-button are assembled after machining.

The blanks produced by the heat treatment according to the invention have little or no porosity (also known as blisters). In the absence of significant porosity, the blank, as well as the machined part, is very strong despite being made of glass. The absence of such a hole makes it possible to machine external parts having more complex shapes, such as watch case 1 comprising middle part 1a and dial 1b of figures 3a, 3b and 4. To produce the watch case, the center of the blank is hollowed out to produce a dial, the middle part being located on top of the periphery of the dial. This machining operation on the glass is particularly delicate. Any porosity can lead to cracking or the formation of unsightly irregularities during machining, thus damaging the part. Likewise, the machining of the periphery of the middle part is critical in particular for shapes with edges, as for the barrel shape of fig. 3 a. If the heat treatment is not optimized, these edges may also initiate crack formation or lead to bar separation due to the presence of voids between the bars.

Furthermore, the absence of porosity makes it possible to prevent the penetration of moisture into the watch case and thus to ensure a certain waterproofness of the watch.

The exterior part produced by this manufacturing method therefore has a very good aesthetic effect, with a 3D pattern of coloured or transparent protrusions.