CH699680B1 - Device for fixing a fragile movable on a support member. - Google Patents

Abstract

Fixing device for fixing a mobile (1) made of a brittle material on a support element (2) the mobile (1) having an opening (5) for receiving the support element (2); the fixing device comprises an intermediate piece (6) of elastically deformable material adapted to be fixed in the opening (5) and having a central hole; the intermediate piece (6) being able to redistribute a part of the stresses exerted by the support member (2) when the latter is driven into the central hole. The invention also relates to an assembly comprising a mobile fixed on the support member (2) and the fixing device, and a watch movement comprising this assembly.

Description

Technical area

The present invention relates to a device for fixing a mobile pivoting on a support member, more particularly, a mobile made of a relatively fragile material such as glass, quartz or silicon. The present invention also relates to a device for fixing a watchmaker and a movement comprising one or more mobiles fixed according to the fixing device of the invention.

State of the art

In the field of micromechanics, which will subsequently be more particularly illustrated by the watchmaking field, the hunting technique is widely used, for example to secure a wheel on a shaft. When the material constituting the part has a plastic domain, which is the case of metals and alloys, it is known to calculate the tolerances necessary for the shaft and the bore so as to have a tight fit without risk of breaking the part, or to distort it. When the material does not have, or very little, plastic field, which is the case of glass, quartz or silicon, there is a great risk of breaking the workpiece during assembly.

However, these materials are increasingly used in watchmaking due in particular to their insensitivity to magnetic fields, their very low coefficient of thermal expansion, and their density much lower than that of metals or alloys. In addition, modern machining technologies enable complex shapes to be produced with great precision.

If one makes a bold adjustment to avoid stress in the brittle material, then there is a risk of disengagement or non-drive of a movable member by the shaft. To overcome this drawback, it is possible to use the bonding technique, long used to fix a hairspring on a ferrule, as described, for example, in patent FR 1 447 142. US Pat. No. 3,906,714 describes an embodiment in which the point glue allows both to fix the hairspring to a ferrule ring and said ring to the balance shaft.

The use of a glue, however, has the disadvantage of requiring additional machining steps to provide housing for the glue, and additional tasks at the time of assembly. In addition aging phenomena can cause a certain game over time.

In WO 2 007 099 068, a micromechanical component manufactured in quartz or silicon for a watch movement, comprises zones with elastic deformation ensuring the clamping during its driving on an axis.

Similarly in the application EP 1 826 635, a micromechanical component manufactured in silicon comprises an elastic deformation zone composed of elastic arms machined in the silicon, so as to facilitate assembly of the part on an axis.

However, such elastic zones are likely to cause a radial movement of the mounted part on the shaft. In addition, these elastic zones, consisting of relatively thin structures cut in the room near the shaft, tend to weaken the part so, on the one hand, that the part is resistant to shocks, frequent especially in a timepiece, and, secondly, to increase the risk of breakage when hunting the room on the tree.

Brief summary of the invention

An object of the present invention is to provide a fixing device free of limitations of the state of the art.

Another object of the invention is to provide a fixing device for fixing a mobile made of a fragile material, that is to say, a material having no or very little plastic field in normal operating temperatures, such as glass, quartz or silicon, on a support member so that the stresses exerted by the support member on the mobile are redistributed to minimize the risk of damage and / or rupture of the mobile during its assembly and operation.

According to the invention, these objects are achieved in particular by means of an intermediate piece of elastically deformable material intended to be fixed in an opening in the mobile and having a central hole in which the support member is driven.

The invention also relates to an assembly comprising the mobile fixed on a support member and the fixing device.

In one embodiment of the invention, the mobile is an escape wheel and the support member is an exhaust pinion.

In another embodiment of the invention, the mobile is an anchor and the support member is an anchor rod.

In yet another embodiment of the invention, the mobile is a dual exhaust tray and the support member is a balance shaft.

The fastening device of the invention has the advantage over the prior art of minimizing the need for lubrication, reduce wear and the inertia of the moving assembly - support element, and than to facilitate the assembly of parts.

Brief description of the figures

Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which: <tb> fig. 1 <SEP> illustrates the device for attaching a mobile to a support element according to a first embodiment of the invention; <tb> fig. 2 <SEP> illustrates an intermediate piece according to a variant of the embodiment; <tb> fig. 3 <SEP> shows a central portion of an escape wheel viewed from below; <tb> fig. 4 <SEP> shows an exhaust pinion driven into a central hole of the intermediate piece; <tb> fig. <SEP> shows the intermediate piece having a lug and a structure at its outer periphery; <tb> fig. 6 <SEP> shows the intermediate piece having a lug being housed in a notch made in the mobile; <tb> fig. 7 <SEP> illustrates an opening made in the mobile according to a variant of the embodiment of the invention; <tb> fig. [SEP] illustrates the support element driven into the opening of the mobile according to a variant of the embodiment of the invention; <tb> fig. [SEP] illustrates another variant of the embodiment of the invention wherein a washer is driven on the support member; <tb> fig. 10 <SEP> shows a watch anchor mounted on an anchor rod; <tb> fig. 11 <SEP> shows a detail of the watch anchor mounted on the anchor rod; and <tb> fig. 12 <SEP> shows a double exhaust plate pivoted on a balance shaft.

Example (s) of embodiment of the invention

Figs. 1 to 12 show different embodiments of a fixing device of the invention for assembling a mobile, for example, a watch mobile such as a wheel, an anchor or a double plate on a support member such as an axle or pinion.

In a first embodiment, illustrated in FIGS. 1 to 9, the mobile, here an escape wheel 1, is pivotally mounted on the support member, an exhaust pinion 2 made of steel, brass or other alloy, in this example.

In the example of FIG. 1, the escape wheel 1 comprises a serge 3 provided with an escape toothing and five arms 4. Other configurations of the wheel 1 are also possible, the wheel 1 may, for example, comprise a different number of arms of various shapes, or take the form of a solid disc (not shown). The wheel 1 also comprises an opening 5 intended to receive the exhaust pinion 2. The example of FIG. 3 shows such an opening 5 of round shape where the center of the wheel 1 is seen from below. The opening 5 may also have a non-rounded shape (not shown), for example being of polygonal shape, for example square, pentagonal or hexagonal, etc., depending on the properties of the material and / or the manufacturing process used in the manufacture of the mobile 1.

The mobile is typically made of a fragile material, that is to say, a material having no plastic field in normal temperatures of use, such as glass, quartz or silicon. The mobile can be manufactured by a micro-machining process similar to the methods already used for example for the manufacture of integrated circuits or micromechanical element made of silicon or glass. In the case of silicon, in particular, the mobile can be manufactured using a wet or dry machining process, such as the DRIE process (Deep Reaction Ion Etching). The silicon mobile may also include a coating of silicon oxide or diamond.

As illustrated in FIGS. 1 to 4, the fixing device of the invention comprises an intermediate piece 6 of elastically deformable material, fixed in the opening 5 of the wheel 1 by being either tightened without clamping or driven. The intermediate piece 6 comprises a central hole 7 allowing the reception and clamping, for example by driving, of the support member 2 in the central hole 7, thus deforming the intermediate piece 6 by tightening it in the opening 5. In the example of fig. 4, showing a view in a section perpendicular to the plane of the escape wheel 1, the exhaust pinion 2 comprises at one end a plate 10 which is driven into the central hole 7. By deforming, the intermediate piece 6 redistributes a portion of the stresses exerted by the support member 2, to prevent these stresses are concentrated at particular points of the wheel 1, including stops in the case where the opening 5 has, for example, a shape polygonal. The risk of damage and rupture of the wheel 1 are reduced during its assembly and operation, particularly in cases where the wheel 1 is made of a fragile material.

The intermediate piece 6 may be made of a plastic material, preferably characterized by good dimensional stability, good abrasion resistance, and allowing reduced wear and friction. In a preferred embodiment of the invention, the intermediate piece 6 is made of polyoxymethylene, for example Delrin <®>. The shaping of the intermediate part 6 is preferably carried out by injection molding, but can also be carried out by extrusion, stamping or machining.

In a variant of the embodiment, the intermediate piece 6 is made of a soft metal such as gold, brass, bronze, nickel, copper or alloys thereof. A copper-beryllium alloy can also be advantageously used for its mechanical and tribological properties.

The intermediate piece 6, shown isolated in FIG. 2, has a structure 8 of bumpy shape on its outer periphery, so as to allow greater deformability of the intermediate part 6 when it is driven into the opening 5. Other forms of structure 8 are also possible, for example example ribs or grooves (not shown), fulfilling the same function as the bump form. The outer periphery may also be smooth, as shown in the example of FIG. 4. As can be seen in particular in FIGS. 2, 4 and 5, the intermediate part 6 may also comprise a flange 9 coming to bear against the upper face of the moving body when the part 6 is driven into the opening 5, thus allowing its axial positioning. The piece 6 may also have the shape of a hollow cylinder having no flange.

In another embodiment of the invention shown in FIG. 3, the central hole 7 comprises a flat part 11, able to conform to the shape of the driven part of the support element 2, so as to mount the intermediate part 6 non-rotatively on the support element 2. Other configurations of the central hole 7 and the support member 2 are also possible. For example, the central hole 7 and the support member 2 may have conformal notches or grooves (not shown).

In another variant of the embodiment shown in FIGS. 5 and 6, the rim 9 of the intermediate piece has a lug 12 extending radially outwardly, and being housed in a notch 13 of corresponding shape, formed in the mobile 1 and visible in FIG. 6, showing a view from below of the central portion of the wheel 1. The lug 12 makes it possible to mount the intermediate piece 6 in a non-rotating manner and according to a predetermined positioning on the wheel 1. The lug may also extend over the entire height of the intermediate piece 6.

In yet another variant of the embodiment shown in FIG. 7, the shape of the opening 5 is in accordance with the form, for example embossed, of the structure 8 of the intermediate part 6 as shown in the examples of FIGS. 2 and 5. The conformity of the shape of the opening 5 and the structure 8 allows a non-rotating and predetermined positioning of the wheel 1 on the support element 2. The intermediate part 6 may also comprise the lug 12 and the structure 8, for example of bumpy shape, as illustrated in FIG. 5.

In yet another variant of the embodiment shown in FIG. 8, the support element 2 is directly driven into the opening 5 of the wheel 1. In this example, the opening 5 is round in shape and comprises the flat part 11, conforming with the shape of the plate 10. Here the wheel 1 can be fixed to the plate 10 by means of a glue point placed on the periphery of the plate 10 and / or the opening 5. The wheel 1 can also comprise an opening 5 of polygonal shape or the like .

In yet another variant of the embodiment shown in FIG. 9, showing a view in a section perpendicular to the plane of the escape wheel 1, a washer 14 is driven on the plate 10 above the wheel 1, and abuts with the wheel 1 so as to maintain it in a fixed manner on the plate 10. The washer 14 may be made of a plastic material such as polyoxymethylene, for example Delrin®, or in a soft metal such as gold, brass, bronze, nickel, copper or alloys thereof. Preferably, the washer 14 is made of a copper-beryllium alloy. The use of the washer 14 allows glue-free fixing the mobile on the support member.

Still in another variant not shown of the embodiment, the mobile is driven directly or through the intermediate piece 6 on the support member, made of plastic such as polyoxymethylene, for example, the Delrin <®>.

The intermediate piece 6 and the support member 2 can be made in one piece. In this case, the intermediate piece 6 and the support member 2 are made of copper-beryllium alloy or a plastic material such as polyoxymethylene, for example Delrin <®>.

In another embodiment of the invention shown in FIGS. 10 and 11, the mobile, here a watch anchor 15 comprising a rod 17, is pivotally mounted on the support member, here an anchor rod 16. FIG. 11 shows a portion of this assembly close to the anchor rod 16, in a section perpendicular to the plane of the anchor 15. The anchor rod 16 is driven into the central hole 7 of the intermediate piece 6, the flange 9 of the piece 6 abutting against the upper face of the anchor 15. In this example, a washer 14 is also driven on the anchor rod 16 and abuts against the underside of the anchor 15 so as to position and / or axially fix it on the anchor rod 16. In a variant of the embodiment, the anchor 15 is fixed on the anchor rod 16 without the washer 14.

In yet another embodiment of the invention shown in FIG. 12, the mobile, here a double exhaust plate 18 having a pin 19, is pivotally mounted on the support member, here a balance shaft 20. A portion of a spiral 21 and a balance beam 22 of a clock control system, also mounted on the balance shaft 20, are also visible in FIG. 12. In this example, the intermediate piece 6 of cylindrical shape is driven into a cavity 23 of the double plate 18 and the balance shaft 20 is driven into the central hole 7 of the intermediate part 6. The cavity 23 has a shoulder 24 allowing axially position the intermediate part 6 along the cavity 23. The intermediate part 6 may comprise a structure 8, for example of bumpy shape. The double tray 18 is preferably made of steel, brass or glucydur, but can also be made of another material.

The fixing device of the invention can be advantageously used in a watch movement comprising mobile fragile material, such as silicon or silicon coated with diamond, mounted on their respective support elements. For example, a regulating member of a watch movement (not shown) may comprise an escape wheel 1, an anchor 15 and a double exhaust plate 18 each comprise an intermediate piece 6 fixed in an opening 5 made in each of the mobiles 1, 15, 18; the intermediate piece 6 having a central hole 7 in which an escape gear 2, an anchor rod 16 and a balance shaft 20, respectively, are driven.

It goes without saying that the fastening device of the invention is not limited to the embodiments which have just been described and that various modifications and variants may be envisaged by the skilled person without departing from the scope of the present invention.

For example, the mobile of the invention can also be a watchmaking construction element such as a gear wheel or an oscillating weight mounted on a pinion, or a plate, a bridge or a dial, mounted on a or feet.

The fixing device of the invention can also be used for mounting a mobile such as a non-watchmaking micromechanical part, having, for example, a functional role in a printed circuit or a MEMS.

Reference numbers used in the figures

[0039] <tb> 1 <SEP> escape wheel <tb> 2 <SEP> exhaust pinion <Tb> 3 <September> serge <Tb> 4 <September> arm <Tb> 5 <September> opening <tb> 6 <SEP> intermediate part <tb> 7 <SEP> central hole <Tb> 8 <September> structure <Tb> 9 <September> flange <Tb> 10 <September> plate <Tb> 11 <September> flat <Tb> 12 <September> lug <Tb> 13 <September> notch <Tb> 14 <September> washer <Tb> 15 <September> anchor <tb> 16 <SEP> anchor rod <Tb> 17 <September> wand <tb> 18 <SEP> double exhaust tray <Tb> 19 <September> Ankle <tb> 20 <SEP> balance shaft <Tb> 21 <September> spiral <Tb> 22 <September> pendulum <Tb> 23 <September> cavity <Tb> 24 <September> shoulder

Claims (16)

A fixing device for fixing a mobile (1, 15, 18) made of a brittle material on a support member (2, 16, 20); the mobile (1, 15, 18) having an opening (5) for receiving the support member (2, 16, 19); characterized in that the fixing device comprises an intermediate piece (6) of elastically deformable material adapted to be fixed in the opening (5) and having a central hole (7); the intermediate piece (6) being able to redistribute a part of the stresses exerted by the support member (2, 16, 20) when the latter is driven into the central hole (7). 2. Device according to claim 1, characterized in that the intermediate piece (6) is made of a plastic material. 3. Device according to claims 1 or 2, characterized in that the intermediate piece (6) is made of polyoxymethylene. 4. Device according to one of claims 1 to 3, characterized in that the intermediate piece (6) comprises, on its outer periphery, a structure (8) of embossed shape. 5. Device according to one of claims 1 to 4, characterized in that the intermediate piece (6) has a lug (12) intended to be housed in a notch (13) of corresponding shape, formed in the mobile (1, 15, 18). 6. Device according to one of claims 4 to 5, characterized in that the shape of the structure (8) of the intermediate piece (6) is chosen to conform to the shape of the opening (5). 7. Assembly comprising a mobile (1, 15, 18) fixed on a support element (2, 16, 19), the mobile being made of a fragile material and having an opening (5) for receiving the element support, the assembly also comprising the fixing device according to one of claims 1 to 6, characterized in that the mobile (1, 15, 18) is made of silicon. 8. Assembly according to claim 7, characterized in that the mobile (1, 15, 18) has a coating of silicon oxide or diamond. 9. Assembly according to claim 7 or 8, characterized in that the support element (2, 16, 20) is made of plastic material and is driven directly into the opening (5). 10. Assembly according to claim 9, characterized in that the support element (2, 16, 20) is made of polyoxymethylene. 11. Assembly according to one of claims 7 to 9, characterized in that the mobile is an escape wheel (1) and the support element is an escape pinion (2). 12. Assembly according to one of claims 7 to 9, characterized in that the mobile is an anchor (15) and the support member is an anchor rod (16). 13. Assembly according to one of claims 7 to 9, characterized in that the mobile is a double exhaust plate (18) and the support element is a balance shaft (20). 14. Watch movement comprising the assembly according to one of claims 7 to 13. 15. Watch movement according to claim 14, wherein the assembly comprises mobiles comprising at least one escape wheel (1), an anchor (15) and a double exhaust tray (18) made of a fragile material and respectively mounted on support members comprising at least one escape pinion (2), an anchor pin (16) and a rocker pin (20), respectively, characterized in that the mobiles (1, 15, 18) each comprise an intermediate piece (6) fixed in an opening (5) formed in each of the mobiles (1, 15, 18); the intermediate piece (6) having a central hole (7) in which the support members (2, 16, 20) are respectively driven out. Clock movement according to claim 14 or 15, characterized in that the mobiles (1, 15, 18) are made of silicon or silicon coated with diamond.