CH703338A2 - Coaxial escapement mobile for coaxial escapement system of timepiece, has secondary tooth formed of single piece with board, where board is formed of hub connected to primary tooth using arm - Google Patents

Abstract

The mobile (100) has a primary tooth (108) formed at a periphery of a board (103). A secondary tooth (113) is formed of a single piece with the board. The board is formed of a hub (102) connected to the primary tooth using an arm (106). The board comprises an opening (104) cooperating with an axle to mount the mobile, where the mobile is made of metal or metal alloy or silicon based material. The opening includes elastically deforming attachment units (105) to clamp the axle on the board. Independent claims are also included for the following: (1) a coaxial escapement system comprising a pallet assembly (2) a method for fabrication of a mobile.

Description

Field of the invention

The invention relates to a single-piece mobile for example of the coaxial escapement type and more particularly to such a mobile material micro-machinable or electroformable.

Background of the invention

In known manner, the escapement of a clockwork mechanical movement, whether Swiss or coaxial anchor, comprises an escape wheel whose regularly spaced teeth are shocked pallets generally ruby.

An example of a coaxial exhaust system is presented in EP 1 045 297. Such a mechanism as illustrated in FIG. 11 comprises a mobile formed of a first 1 and a second 11 escape wheels. This second escape wheel 11, also called the impulse pinion, is mounted on the same axis 3. The angular position of the teeth 13 of the second escape wheel 11 is indexed to the angular position of the teeth 8 of the first wheel exhaust 1.

The first escape wheel 1 has the shape of a classic Swiss anchor escapement wheel. The second escape wheel 11 also acts as an escape pinion 15 meshing with an intermediate wheel 17, which has the advantage of reducing the height of the mechanism.

The large plate 19 of the balance (not shown) carries a plate pin 21 and a pulse pallet 23. The first 21 is intended to drive, in a back-and-forth motion, the anchor 25 via its fork 27 while the second 23 is intended to cooperate with the teeth 8 of the first escape wheel 1.

The anchor 25 comprises a pulse pallet 24 which cooperates with the teeth 13 of the second escape wheel 11. The anchor 25 also comprises two other pallets of rest 26, 28 respectively input and output which cooperate with the teeth 8 of the first escape wheel 1.

The construction of such a coaxial escapement requires a very high accuracy, especially at the level of the relative alignments between the first 1 and second 11 exhaust wheels, which makes it difficult to manufacture. In addition, in general, the workings of a two-level timepiece like the usual wheel-pinion type have always required a perfect indexing between them.

Summary of the invention

The object of the present invention is to overcome all or part of the disadvantages mentioned above by providing a mobile such as a coaxial escapement mobile whose alignment problems are reduced and whose inertia is reduced.

For this purpose, the invention relates to a single-piece mobile having a first toothing formed on the periphery of a board and a second toothing characterized in that the second toothing is formed in one piece with the board of the first gear to reduce the alignment problems with respect to each other and reduce the overall mass of the mobile and, in particular, such a mobile coaxial escape type whose first gear is arranged to cooperate with an ankle and to less a first series of pallet and a second toothing arranged to cooperate with a second series of pallet.

We immediately understand the interest of such a mobile by the simplicity of construction (monobloc and less material) compared to two parts that are difficult to adjust with respect to each other currently.

According to other advantageous features of the invention: the board comprises an opening intended to cooperate with an axis in order to rotate said coaxial escapement wheel; the opening comprises fastening means with elastic deformation to clamp the axis without exerting destructive stress on the board; the opening comprises fixing means plastic deformation to tighten the axis without exerting destructive stress on the board; the mobile may be metal or a metal alloy or silicon-based.

In addition, the invention relates to a coaxial exhaust system for a timepiece comprising an anchor intended to cooperate with a monobloc coaxial exhaust mobile according to one of the preceding variants, the first gear of mobile being arranged to cooperate with a peg secured to a rocker and being intended to cooperate with a first pallet series of the anchor, the second toothing being intended to cooperate with a second pallet series of the anchor and arranged to form the exhaust pinion.

Finally, the invention relates to methods of manufacturing a mobile. According to a first embodiment of micro-machinable materials such as silicon carbide, crystallized silicon, crystallized alumina or crystallized silica, the manufacturing method comprises the following steps: <tb> a) <sep> provide a substrate comprising an upper layer and lower layer of micro-machinable materials which are joined together by an intermediate layer; <tb> b) <sep> etching at least one pattern in the upper layer until discovering the intermediate layer to form at least a first toothing of said mobile at the periphery of a board; <tb> c) <sep> etching a second pattern in the lower layer until uncovering the intermediate layer to form at least a second toothing integrally with said board of the first toothing; <tb> d) <sep> release the mobile thus formed substrate.

According to a second embodiment of pure metal or metal alloy, the manufacturing method comprises the following steps: <tb> a ') <sep> to provide a substrate comprising an electrically conductive upper layer; <tb> b ') <sep> forming a mold and filling it with the material forming said mobile, using at least one substance on two levels, the first level comprising at least one cavity forming at least one first toothing of said mobile at the periphery of a board and the second level having a recess forming at least a second toothing of said mobile and communicating with said at least one cavity of the first level; <tb> c ') <sep> release the mobile thus formed of said at least one substance and the substrate.

Brief description of the drawings

Other features and advantages will become apparent from the description which is given below, for information only and in no way limitative, with reference to the accompanying drawings, in which: <tb> - figs. 1 to 4 <sep> are representations of the successive steps of a method of manufacturing an escape wheel according to a first embodiment of the invention; <tb> - figs. 5 to 8 <sep> are representations of the successive steps of a method of manufacturing an escape wheel according to a second embodiment of the invention; <tb> - fig. 9 <sep> is a perspective representation of a coaxial escapement mobile according to a first variant of the invention; <tb> -the fig. 10 <sep> is a perspective representation of a coaxial escapement mobile according to a second variant of the invention; <tb> -the fig. 11 <sep> is a perspective representation of a coaxial type exhaust system.

Detailed Description of the Preferred Embodiments

Advantageously according to the invention, the alignment problems between the first and second wheels are reduced by manufacturing a mobile 100, 100 grouping said wheels integrally, that is to say in one piece . As a result, only the teeth 113, 113 of one of the wheels are still necessary, which implies that most of the board of one of the two wheels is no longer useful, thus also allowing the reduction of the mass of the wheel. exhaust 100, 100 and, incidentally, its inertia. For simplicity, the following explanation is made from a coaxial escape wheel. However, it is understood that any type of mobile at least two levels is applicable to the present invention.

As illustrated in FIGS. 9 and 10, two exemplary embodiments according to the invention of one-piece coaxial exhaust mobiles 100, 100 are presented. These mobiles 100, 100 have two distinct patterns on each level.

According to the first embodiment, visible in FIG. 9, the first pattern forms a toothed wheel 101 corresponding to the first escape wheel 1 of FIG. 11. It comprises a board 103 forming a hub 102 whose center comprises an opening 104 and from which the arms 106 from which each end forms a tooth 108 corresponding to a tooth 8 of FIG. 11. A board 103 is thus obtained comprising a first toothing at its periphery.

As illustrated in FIG. 9, the opening 104 comprises resilient fixing means 105 intended to cooperate radially with an axis of the type of that referenced 3 in FIG. 11 by elastic deformation in order to rotate the escape wheel 101 and, consequently, the escapement wheel 100. These resilient fixing means 105 are formed by slender portions made by recessing a portion of the hub 102. The slender portions allow to tighten the axis, that is to say, to secure the mobile 100 of the latter, without stressing the rest of the board 103.

Of course, other elastic means are conceivable. Such elastic means may, for example, take the form of those disclosed in FIGS. 10A to 10E of document EP 1 655 642 or those disclosed in FIGS. 2 to 5 of document WO 2007/099068, which documents are incorporated by reference in the this description.

Thus, advantageously according to the invention, instead of bringing a second escape wheel 11 as in FIG. 11, the mobile 100 being integral, the second unit 111, projecting from the first 101, is formed solely by a second set of teeth 113 corresponding to the teeth 13 of FIG. 11.

Preferably according to the invention, the teeth 113 are independent of each other and are integral with the arms 106. In the particular example of FIG. 9, it is noted that each tooth 113 is integral with a separate arm 106. It is thus clear that the second toothing has as many teeth 113 as the board 103 has arms 106. However, this feature is not essential, there could very well be several teeth 113 on a single arm 106.

According to the second embodiment, visible in FIG. 10, the first pattern forms a toothed wheel 101 corresponding to the first escape wheel 1 of FIG. 11. It comprises a board 103 forming a hub 102 whose center has an opening 104 and from which the arms 106 from which each end forms a tooth 108 corresponding to a tooth 8 of FIG. 11. A board 103 is thus obtained comprising a first toothing at its periphery.

As illustrated in FIG. 10, the opening 104 comprises plastic fixing means 107 intended to cooperate radially with an axis of the type of that referenced 3 in FIG. 11afin to rotatably mount the escape wheel 101 and, therefore, the escape mobile 100. These plastic fixing means 107 are formed by a washer made of metallic material enabling the mobile 100 to be driven against said axis by plastic deformation without subjecting the board 103 to stress. Of course, other plastic fixing means are possible.

Thus, advantageously according to the invention, instead of bringing a second escape wheel 11 as in Figure 11, the mobile 100 being monoblock, the second pattern 111, projecting from the first 101, is only formed by a second set of teeth 113 corresponding to the teeth 13 of FIG. 11.

Preferably according to the invention, the teeth 113 are independent of each other and are integral with the arms 106. In the particular example of FIG. 10, it is noted that each tooth 113 is integral with a separate arm 106. It is therefore understood that the second set of teeth has as many teeth 113 as the board 103 has arms 106. However, this feature is not essential, it could very well be several teeth 113 on a single arm 106.

These two embodiments of FIGS. 9 and 10 can be formed using many different materials. However, an electroformable material, on the one hand, or a micro-machinable material, on the other hand, are preferred. Indeed, to date, reactive ion etching and electroforming type LIGA are the only processes capable of producing parts with the precision of the order of a few microns necessary for the proper operation of the coaxial mobile 100, 100. However, any other process that can meet the same manufacturing tolerances is applicable.

An electroformable material may be formed with gold and / or copper and / or silver and / or indium and / or platinum and / or palladium and / or nickel without these compounds are exhaustive. Indeed, other compounds such as phosphorus can be added in a smaller amount. A micro-machinable material can be formed by silicon carbide, crystallized silicon, crystallized alumina or crystallized silica without these compounds being equally exhaustive.

Both types of manufacture will be presented respectively in FIGS. 1-4 and 5-8. FIGS. 1 to 4 present successive main stages of a micromachining for a better understanding. Preferably, the method comprises a first step consisting in providing a substrate 31 comprising an upper layer 33 and a lower layer 35 made of micro-machinable materials which are interconnected by an intermediate layer 34. This type of substrate 31 is also known. under the abbreviation SOI from the English words "Silicon On Insulator".

In a second step, etching of at least one pattern 36 in the upper layer 33 to discover the intermediate layer 34 to form at least a first tooth (teeth 108, 108) of the mobile d exhaust 100, 100 at the periphery of a board 103, 103. This second step thus makes it possible to form one or more first pattern (s) 101, 101 of the mobile 100, 100 in the upper layer 33.

As illustrated in FIG. 2, a mask 37 is formed, for example by photolithography, to protect the part of the upper layer 33 that it is desired to keep and, as illustrated by broken lines, the upper part of the substrate 31 is subjected to anisotropic etching. deep reactive ion etching type also known by the abbreviation DRIE from the words "Deep Reactive Ion Etching". As shown in fig. 3, the first pattern 36 having a first level 101, 101 of at least one escape wheel 100, 100 is obtained.

In a third step, etching of at least a second pattern 38 in the lower layer 33 to find the intermediate layer 34 to form at least a second toothing (teeth 113, 113) so monobloc with the board 103, 103 of the first toothing (teeth 108, 108) of the escape wheel 100, 100. This third step therefore makes it possible to form one or more second pattern (es) 111, 111 'of the mobile 100, 100 in the lower layer 35.

As illustrated in FIG. 3, a mask 39 is formed, for example by photolithography, to protect the part of the lower layer 35 that it is desired to keep and, as illustrated by broken lines, the lower part of the substrate 31 is subject to anisotropic etching. deep reactive ion etching type (DRIE). As shown in fig. 4, the second pattern 38 having at least a second level 111, 111 is obtained in a monoblock manner with one of the first levels 101, 101 formed in the preceding steps.

It remains more than to release each mobile 100, 100 on two levels thus formed of the substrate 31 and, optionally, uncovered portions of the intermediate layer 34 to mount the exhaust mobile 100, 100 in the definitive exhaust system. Preferably, when the escape wheel 100, 100 is formed based on silicon, an additional oxidation step is performed in order to form at least a portion of silicon dioxide at its outer surface for the purpose of make it more mechanically strong.

Figs. 5-8 present successive main steps of electroforming for better understanding. Preferably, the method comprises a first step of providing a substrate 41 having an electrically conductive upper layer. This layer can be obtained by the deposition of an electrically conductive material on an insulating material or in that the substrate is formed of an electrically conductive material.

The main steps of electroforming consist in forming a mold and then filling the mold with a material, for example, using electroplating. This type of electroforming is known by the abbreviation L.I.G.A. from the German terms "roaming, lithography, galvanoformung & abformung". There are several types of L.I.G.A. next that the multi-level mold is formed between each electroplating or is formed entirely to be, only after, filled. For the explanation below, the technique presented consists in forming each level, that is to say forming a level of the mold and filling it before going to the next level. Of course, any type of electroforming, type L.I.G.A. or not, able to form a mobile unit in at least two distinct levels is possible.

As illustrated in FIGS. 5 and 6, in a first step, the first level 47 of the mold is formed using, for example, a photolithography of a resin as illustrated in FIG. 5. At least one cavity of corresponding shape is formed at the first pattern 101, that is at least one first toothing (teeth 108, 108) of the escape wheel 100, 100 at the periphery. of plate 103, 103. The first level is then filled by electroplating a metal material 46.

As illustrated in FIG. 7a similar manner to the first time, in a second step, the second level 49 is formed using, for example, also a photolithography of a resin. At least one recess of corresponding shape is formed at the second unit 111, 111, that is to say at least one second toothing (teeth 113, 113) of the escape wheel 100, 100 and communicating with said at least one cavity of the first level 47. The second level 49 is then filled by electrodeposition of a metallic material 48.

It remains more than to release the mobile 100, 100 on two levels thus formed of the substrate 41 and resins 47, 49 as shown in FIG. 8 to mount the escape wheel 100, 100 in the final exhaust system. In the example of an escapement wheel 100, 100 obtained by electroforming, it is understood that it is no longer necessary to form the elastic or plastic fastening means 17 because the metallic material can be driven directly. on the axis by its opening 104, 104.

Of course, the present invention is not limited to the illustrated example but is subject to various variations and modifications that will occur to those skilled in the art. In particular, alternatively, it is also conceivable that the toothed wheels 101, 101 may comprise a serge like that 9 of FIG. It does not depart from the scope of the present invention.

In addition, even if the example of a coaxial escapement wheel is presented above, it is obvious that a mobile wheel-gear type of a cog or even a usual escape wheel will have the same benefits. The first toothing 108, 108 would be that of the wheel and the second toothing 113, 113 that of the pinion or vice versa.

Finally, it should be understood that at least two levels are made integrally. Thus, it is perfectly conceivable that at least one additional level is formed under the board, that is to say the face opposite to that supporting the second set of teeth 113, 113, and / or above it.

Claims (16)

1. A one-piece mobile (100, 100) having a first toothing (108, 108) formed on the periphery of a board (103, 103) and a second toothing (113, 113) characterized in that the second toothing (113, 113) is integrally formed with the board (103, 103) of the first toothing (108, 108) to reduce alignment problems with respect to each other and reduce the overall mass of the mobile (100, 100). 2. A one-piece coaxial escapement (100, 100) having a first toothing (108, 108) formed on the periphery of a board (103, 103), the first toothing (108, 108) being arranged for cooperating with an anchor and at least a first pallet series, a second toothing (113, 113) arranged to cooperate with a second pallet series characterized in that the second toothing (113, 113) is formed in one piece with the board (103, 103) of the first toothing (108, 108) in order to reduce the problems of alignment with respect to each other and to reduce the overall mass of the escape wheel (100, 100). 3. Mobile (100, 100) according to claim 1 or 2, characterized in that each tooth (113, 113) of the second toothing is independent of one another and is projecting from the board (103, 103) of the first toothing (108, 108). 4. Mobile (100, 100) according to the preceding claim, characterized in that the board (103, 103) is formed of a hub (102, 102) connected to the first toothing with the aid of at least one arm (106, 106). 5. Mobile (100, 100) according to the preceding claim, characterized in that each tooth (113, 113) of the second toothing is secured to said at least one arm of the board (103, 103). 6. Mobile (100, 100) according to the preceding claim, characterized in that the second toothing has as many teeth (113, 113) that the board (103, 103) comprises arms (106, 106). 7. Mobile (100, 100) according to one of the preceding claims, characterized in that the board (103, 103) comprises an opening (104, 104) for cooperating with an axis (3) to mount rotating said coaxial escapement wheel (100, 100). 8. Mobile (100) according to the preceding claim, characterized in that the opening (104) comprises resilient deformation fixing means (105) for clamping the axis (3) without exerting destructive stress on the board ( 103). 9. Mobile (100) according to claim 7, characterized in that the opening (104) comprises plastically deformation fixing means (107) for clamping the axis (3) without exerting destructive stress on the board (103). 10. Mobile (100, 100) according to one of the preceding claims, characterized in that it is metal or a metal alloy. 11. Mobile (100, 100) according to one of claims 1 to 9, characterized in that it is formed in a silicon-based material. 12. Coaxial exhaust system for a timepiece comprising an anchor (25) intended to cooperate with a one-piece coaxial escapement wheel (100, 100) according to one of the preceding claims dependent on claim 2, the first toothing (108, 108) of the mobile (100, 100) being arranged to cooperate with a peg (23) integral with a rocker and being intended to cooperate with a first series (26, 28) pallet of the anchor (25), the second toothing (113, 113) being intended to cooperate with a second pallet series (24) of the anchor (25) and arranged to form the exhaust pinion. 13. A method of manufacturing a mobile (100, 100) comprising the following steps: <tb> a) <sep> provide a substrate (31) having an upper layer (33) and lower layer (35) of micro-machinable materials which are interconnected by an intermediate layer (34); <tb> b) <sep> etching at least one pattern (36) in the top layer (33) until the intermediate layer (34) is exposed to form at least a first set of teeth (108, 108) the periphery of a board (103, 103); <tb> c) <sep> etching a second pattern (38) into the lower layer (35) until the intermediate layer (34) is exposed to form at least one second toothing (113, 113) integrally with said board of the first toothing (108, 108); <tb> d) <sep> release the mobile (100, 100) thus formed of the substrate (41). 14. Method according to the preceding claim, characterized in that the micro-machinable materials comprise silicon carbide, crystallized silicon, crystallized alumina or crystallized silica. 15. A method of manufacturing a mobile (100, 100) comprising the following steps: <tb> a ') <sep> provide a substrate (41) having an electrically conductive upper layer; <tb> b ') <sep> forming a mold (47, 49) and filling it with material (46, 48) forming said mobile, using at least one substance (47, 49) on two levels, the first level (47) comprising at least one cavity forming at least one first toothing (108, 108) of said mobile at the periphery of a board (103, 103) and the second level (49) comprising a recess forming at at least one second toothing (113, 113) of said mobile and communicating with said at least one cavity of the first level (47); <tb> c ') <sep> release the mobile (100, 100) thus formed of said at least one substance (47, 49) and the substrate (41). 16. Method according to the preceding claim, characterized in that the material comprises a pure metal or a metal alloy.