Stone for a clock movement

Abstract

The invention relates to a stone (1) forming a guide element for the pivot (14) of a clockwork axis (12) (13), the stone (1) comprising a main portion (23) intended to be fitted into a housing (19) of a clockwork support (16), such as a clockwork movement plate or bridge, and a hole (15) for the pivot (14) of said axis (12), the stone (1) comprising a protruding portion (22) extending from the periphery of the main portion (23), the protruding portion (22) having said hole (15). The invention further relates to a rotating guide device (10) comprising such a stone (1), and a clockwork movement comprising such a guide device (10).

Description

Technical field of the invention

[0001] The invention relates to a stone for a watch movement, for example an industrial stone or a technical ceramic.

[0002] The invention also relates to a clockwork movement incorporating such a stone. Technological background

[0003] In the current state of watchmaking technology, ruby, zirconia (ZrO2), or sapphire stones are notably used to form counter-pivots or guiding elements, known as bearings, in watch components. These counter-pivots and guiding elements are designed to contact pivots, enabling them to rotate with minimal friction. Thus, they form, for example, all or part of a bearing for a rotating shaft. The guiding elements generally include a through hole for inserting the pivot shaft.

[0004] In principle, synthetic industrial jewels are used in watch movements. The Verneuil process, in particular, is known for manufacturing monocrystalline jewels. Polycrystalline jewels also exist, which are produced by pressing a precursor to obtain a green body of the future jewel using a pressing tool. The jewels are then sintered and machined to obtain a finished shape with the desired dimensions. Specifically, for polycrystalline jewel guide elements, the pressing tool is, for example, equipped with a wire that helps create a rough hole.

[0005] There figure 1This is a schematic representation of a stone 11 forming a guide element for a pivot of a rotating component according to the prior art. The stone 11 is set into a housing 2 of a support 4, here a clockwork movement bridge. In certain configurations, the stone 11 is arranged at the edge 8 of the support 4, when the rotating component requires such a position.

[0006] In this example, stone 11 is circular and has a through hole 5 centered in its middle, stone 11 being concentric. The housing 2 for stone 11 has an opening 6 on the edge 8 of the support 4, and includes two reliefs 3 to balance the forces exerted on stone 11. Thus, stone 11 is held by three bearing faces 7, 9, two bearing faces 7 being arranged between the edge 8 and a different relief 3, and the third bearing face 9 being arranged between the two reliefs 3.

[0007] However, the embedding surface of stone 11 is limited, particularly because of the width of the opening 6 in the border 8, which must be compensated by the two clearances 3. Thus, the three bearing faces 7, 9 offer an insufficient embedding surface, so that stone 11 risks coming loose from the housing in case of impact, because it is not sufficiently held. Summary of the invention

[0008] The aim of the present invention is to overcome all or part of the aforementioned disadvantages by proposing a stone that can be embedded in a housing with a larger embedding surface.

[0009] To this end, the invention relates to a stone forming a guide element for the pivot of a clockwork movement axis, the stone comprising a main part intended to be embedded in the housing of a clockwork support, for example a bridge or a clockwork movement plate, as well as a hole for the pivot of said axis.

[0010] The stone is remarkable in that it includes a prominent part forming an outgrowth arranged at the periphery of the main part, the prominent part containing said hole.

[0011] Thus, this stone can be set in a housing with a larger setting surface, while keeping the guide hole in the opening of the support.

[0012] Indeed, the protruding part containing the hole is in the same position as that of the earlier stone, but the main part of the stone is anchored further inside the support and is larger. Consequently, the embedding surface is greater, so it is better supported and the risk of the stone becoming dislodged is reduced.

[0013] According to a particular embodiment of the invention, the main part has a substantially circular shape.

[0014] According to a particular embodiment of the invention, the main part comprises a truncated face, preferably arranged opposite the prominent part.

[0015] According to a particular embodiment of the invention, the prominent part has a semi-circular shape concentric around the hole.

[0016] According to a particular embodiment of the invention, the stone is of the polycrystalline type, comprising for example poly-ruby of the al2O3Cr type, or preferably Zirconia of the ZrO2 type.

[0017] According to a particular embodiment of the invention, the main part has a diameter greater than the diameter of the prominent part.

[0018] The invention also relates to a rotational guidance device for a clockwork pivot axis, the guidance device comprising a clockwork support, such as a plate or a bridge, provided with a housing, and such a jewel set in the housing.

[0019] According to a particular embodiment of the invention, the housing includes a lateral opening at the edge of the support.

[0020] According to a particular embodiment of the invention, the stone is arranged in the housing so that at least a portion of the protruding part exits the housing through said lateral opening.

[0021] According to a particular embodiment of the invention, the housing is circular outside the opening.

[0022] According to a particular embodiment of the invention, the dimensions of the housing correspond to those of the main part of the stone to allow its embedding.

[0023] The invention also relates to a clockwork movement comprising such a rotational guidance device. Brief description of the drawings

[0024] Other features and advantages will become clear from the description given below, which is indicative and in no way exhaustive, with reference to the attached drawings, in which: there figure 1is a schematic representation of a rotational guidance device according to a known prior art embodiment; the figure 2 is a schematic perspective drawing from below of a portion of a clockwork movement comprising a clockwork mechanism and a rotating guide device according to the invention; the figure 3 is a schematic representation of a cross-sectional view of the axis of a clockwork mechanism mounted in the rotating guide device according to the invention; the figure 4 is a schematic representation of a top view of the rotating guidance device according to the invention, and the figure 5 is a schematic representation of a bottom view of the rotational guidance device according to the invention. Detailed description of preferred embodiments

[0025] As explained above, the invention relates to a stone 1 forming a guiding element for the pivot 14 of a clockwork mechanism axis 12 13 and to a rotational guiding device 10 comprising such a stone 1, as shown in the figures 2 to 4 . Clockwork mobile 13 is, for example, an average mobile.

[0026] The stone 1 is of the polycrystalline type and comprises, for example, poly-ruby of the type Al2O3Cr, or zirconia of the type ZrO2, preferably in its entirety. The stone 1 comprises a main portion 23 and a prominent portion 22 of said axis 12, as well as a hole 15 for the pivot 14. Preferably, the stone 1 has a substantially constant thickness defined in the same plane.

[0027] The main portion 23 is designed to be fitted into the housing 19 of a clockwork support 16, here a clockwork movement bridge. The main portion 23 has a substantially circular shape. The main portion 23 includes a truncated face 21, preferably positioned opposite the protruding portion 22. The truncated face 21 has substantially the same width as the opening 18 of the housing 19 to compensate for the absence of force exerted at that point.

[0028] According to the invention, the stone 1 comprises a prominent part 22 forming an outgrowth extending from the periphery of the main part 23, the prominent part 22 having said hole 15.

[0029] The prominent part 22 has a semi-circular shape concentric around the hole 15. The main part 23 has a diameter greater than the diameter of the prominent part 22.

[0030] The main part 23 and the prominent part 22 of stone 1 form a continuum of matter.

[0031] The guiding device 10 also includes a clockwork support 16, here a bridge, equipped with a housing 19 for the stone 1. The dimensions of the housing 19 correspond to those of the main part 23 of the stone 1 to allow its setting.

[0032] Housing 19 has a lateral opening 18 at the edge 17 of the support 16. Housing 19 is circular outside the opening 18.

[0033] Stone 1 is embedded in housing 19, so as to have at least a portion of the protruding part 22 protruding from housing 19 through said lateral opening 18.

[0034] Such a stone 1 is for example formed from a precursor, shaped into a green body, which becomes a mineral body comprising for example poly-ruby of the al2O3Cr type or zirconia ceramic of the ZrO2 type.

[0035] Stone 1, for example, is produced using a process that includes a first step of creating a precursor from a mixture of at least one powdered material with a binder. The powder may contain aluminum oxide to form synthetic sapphire, or a mixture of aluminum oxide and chromium oxide to form synthetic ruby, or even zirconium oxide.

[0036] In a second pressing stage, the precursor is pressed to form a green body of the future stone. A third sintering stage of this green body forms the mineral body of the future stone in at least one material. The process may include a fourth machining and / or finishing stage.

[0037] Of course, the present invention is not limited to the illustrated example, but is susceptible to various variants and modifications which will become apparent to those skilled in the art.

Claims

1. Stone (1) forming a guide element for the pivot (14) of a clockwork shaft (12) (13), the stone (1) comprising a main part (23) intended to be set into a housing (19) of a clockwork support (16), for example a clockwork movement plate or bridge, as well as a hole (15) for the pivot (14) of said shaft (12), characterized in that it includes a prominent part (22) forming an outgrowth extending from the periphery of the main part (23), the prominent part (22) comprising said hole (15).

2. Pierre according to claim 1, characterized in that the main part (23) has a substantially circular shape.

3. Stone according to claim 1 or 2, characterized in that the main part (23) includes a truncated face (19), preferably arranged opposite the prominent part (22) with respect to the center of the main part (23).

4. Pierre, according to any one of the preceding claims, characterized in that the prominent part (22) has a semi-circular shape concentric around the hole (15).

5. Pierre, according to any one of the preceding claims, characterized in that the stone (1) is of polycrystalline type, comprising for example poly-ruby of type al2O3Cr, or preferably Zirconia of type ZrO2.

6. Pierre, according to any one of the preceding claims, characterized in that the main part (23) has a diameter greater than the diameter of the prominent part (22).

7. Rotational guide device (10) for a shaft (12) of a clockwork mechanism (13), the guide device (10) comprising a clockwork support (16), such as a plate or a bridge, provided with a housing (19), characterized in that it includes a stone (1) according to any one of the preceding claims, the stone (1) being embedded in the housing (19).

8. Guiding device according to claim 7, characterized in that the housing (19) has a lateral opening (18) at the edge (17) of the support (16).

9. Guiding device according to claim 8, characterized in that the stone (1) is arranged in the housing (19), so that at least a portion of the protruding part (22) protrudes from the housing (19) through said side opening (18).

10. Guiding device according to any one of claims 7 to 9, characterized in that the housing (19) is circular outside the lateral opening (18).

11. Guiding device according to any one of claims 7 to 10, characterized in that the dimensions of the housing (19) correspond to those of the main part (23) of the stone (1) to allow its embedding.

12. Clockwork movement, characterized in that it includes a rotational guidance device (10) according to any one of claims 7 to 11.

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