CH711519B1 - Adjustable bridge for timepiece. - Google Patents

Abstract

The invention relates to an adjustable bridge (1) for a timepiece, comprising: at least one mounting element (5) intended to be secured to a frame element of a watch movement; a first mobile element (7) linked to said mounting element (5) by means of a first set of flexible articulations (9a, 9b) allowing it to move substantially along a first axis (Y); a second mobile element (13) linked to said first mobile element (7) via a second set of flexible articulations (15a, 15b) allowing it to move substantially along a second perpendicular axis (X) to said first axis (Y), said second movable element (13) being arranged to support a timepiece (3). The flexible joints being a single piece, they have a flexible part which deforms elastically. According to the invention: said first movable element (7) can be adjusted along the first axis (Y) by turning a head of a first eccentric (23) which takes place in a first elongated slot (19); similarly said second movable element (13) along the second axis (X) by a second eccentric (25) in a second elongated slot (21).

Description

Technical area

The present invention relates to the field of watchmaking. It relates, more particularly, to an adjustable bridge which makes it possible to adjust the position of a timepiece.

State of the art

The document FR 759 765 discloses an adjustable exhaust bridge along three axes, in order to be able to precisely determine the position of the catch which supports the balance axis relative to the plate. This bridge comprises flexible parts and is adjustable by means of screws, as well as by plastic deformation of a thin U or V part of the bridge by means of pliers or the like, which is extremely difficult for the watchmaker to master. , and may require disassembly of the bridge. Adjusting the position of the cockerel is therefore very difficult.

Document CH 34 775 discloses an anchor escapement holder comprising a plate having a slot passing between the pivot point of the fork and that of the anchor wheel. The width of this slot can be slightly increased and decreased by means of two screws acting in the plane of the plate, in order to adjust the distance between the axis of rotation of the anchor and that of the escape wheel which are located respectively on either side of the slot. This adjustment follows in one direction only, and is not suitable for adjustment in two axes.

These arrangements are primitive, difficult to implement, and do not allow fine adjustment along two independent axes in a plane parallel to the movement, without having to plastically deform any element.

An object of the invention is therefore to overcome the drawbacks of the prior art.

Disclosure of invention

More specifically, the invention relates to an adjustable bridge for a timepiece, comprising at least one mounting element intended to be secured to a frame element of a timepiece movement, for example by means of screws, rivets, welding or the like. A first mobile element is linked to said mounting element by means of a first set of flexible articulations arranged to be able to allow the first mobile element to move substantially along a first axis relative to said mounting element, and a second mobile element is linked to said first mobile element by means of a second set of flexible articulations arranged so as to allow the second mobile element to move substantially along a second axis relative to said first mobile element, said second axis being perpendicular to said first axis, said second movable element being arranged to support a timepiece.

According to the invention, the first movable element comprises a first elongated slot extending perpendicular to said first axis and in which is intended to take place a head of a first eccentric mounted in rotation with fatty friction on a frame element of said watch movement, and the second movable element comprises a second elongated slot extending parallel to said second axis and in which is intended to take place a head of a second eccentric mounted in rotation with fatty friction on a frame element of said watch movement .

Easy adjustment in the plane comprising the first and the second axis, which would normally be parallel to the plane of movement is therefore possible, the adjustment along each axis being substantially independent of each other. The use of eccentrics allows the adjustment to be carried out using any tool in a direction perpendicular to the plane of the bridge, which gives a much improved access to the watchmaker, and without requiring any special tool or disassembly of the bridge, which would in particular be the case with a conventional adjustment by screw, the latter requiring actuation in the plane of the bridge.

Advantageously, the bridge is substantially planar and extends in a plane containing said first axis and said second axis.

Advantageously, the bridge is in one piece, which simplifies its production by means of common micromachining processes.

Advantageously, at least one of the first movable member and the second movable member comprises at least one opening extending parallel to said respective slot in order to allow deformation of the wall of said slot. The slot can therefore catch any parasitic displacements and the forces generated between the eccentrics and the walls can be reduced in the event of an impact.

Advantageously, the bridge comprises two mounting elements, the first set of flexible joints comprising two pairs of flexible joints, the two joints of each pair connecting one of the mounting elements to the other and to the first element movable via an intermediate element. Alternatively, the bridge can comprise two mounting elements, the first set of flexible joints comprising two pairs of flexible joints, the two joints of each pair connecting one of the mounting elements to itself and to the first movable element by through an intermediate element. The first movable member is therefore hyper-guided relative to the mounting members, which minimizes any parasitic displacement in an unwanted direction. By "hyperguided" we mean that the first element is guided symmetrically on both sides, as described in section 5.2 of the work "Design of flexible guides", by Simon Henein, PPUR presses polytechniques, 2001.

Advantageously, the second set of flexible joints includes two pairs of flexible joints, the two joints of each pair connecting the first movable member to itself and to the second movable member via an additional intermediate element . The second mobile element is therefore also hyper-guided with respect to the first.

The invention also relates to a timepiece movement comprising a frame, a bridge as described above secured to the frame via said mounting element, a timepiece element supported by said second movable element, a first eccentric comprising a head, said first eccentric being rotatably mounted with fatty friction on an element of said frame and its head taking place in said first slot, and a second eccentric comprising a head, said second eccentric being rotatably mounted on fatty element of said frame and its head taking place in said second slot.

The timepiece can be chosen from a bearing, a pendulum axis, an anchor axis, a mobile axis, or an anchor. The latter can for example be an anchor of a "Genequand" type exhaust which can be rigidly mounted on the bridge.

Finally, the invention relates to an anti-shock device for a timepiece. This shock-absorbing device comprises a bridge as described above, said timepiece being a bearing comprising at least one of a counterpivot stone and a pierced stone intended to receive a pendulum axis.

Thanks to the flexibility imparted to the bridge by the flexible joints, the bridge itself can function as an anti-shock, allowing not only a very precise positioning of the bearing and the reduction of friction associated therewith, but also the use of a rigid bearing, because the elasticity to compensate for shocks is provided by the bridge.

Brief description of the drawings

Other details of the invention will appear more clearly on reading the description which follows, made with reference to the appended drawings in which: <tb> fig. 1 <SEP> illustrates a first embodiment of an adjustment system according to the invention; and <tb> fig. 2 <SEP> illustrates a second embodiment of an adjustment system according to the invention.

Modes of Carrying Out the Invention

[0019] FIG. 1 illustrates a first embodiment of an adjustable bridge 1 according to the invention. The bridge 1 serves as a support for a timepiece 3. By "support" is meant not only "to carry" in the direction of an element secured to the bridge (for example a bearing), but also in the sense of "hold in position », As for example in the case of a mobile axis, a pendulum axis, anchor or the like.

In the embodiment of this figure, the timepiece element 3 is an anchor of a “Genequand” type regulator 4, which is integral with the bridge 1. This kind of regulator is described on the website http: //www.horloqerie-suisse.com/horlomaq/articles-horloqers/00232/un-nouvel-echaust-dans-un-mouvement-avec-une-reserve-de-marche-de-30-jours and must not be described in more detail. However, the same principle applies to a bearing, an axis of a conventional anchor, a pendulum axis, an axis of a mobile or the like. By adjusting the position of the anchor parallel to the XY plane, we allow the 'precise adjustment of the penetration of each of the two pallets 3a of the anchor relative to the teeth of the escape wheel 4a.

The bridge 1 comprises two mounting elements 5, which are intended to be secured to a frame element of a clockwork movement, by means of screws, a solder or the like. It is also possible to envisage bridges which comprise only one mounting element 5, or which include more.

Bridge 1 is constructed as an XY table with flexible joints extending in an XY plane. Such joints, also called “flexures”, are formed by elastic blades or necks made integrally with the bridge 1. These joints, in comparison with a hinged joint, have no play, no friction, and therefore neither hysteresis. A standard work on such articulations is the book “Design of flexible guides”, by Simon Henein, PPUR presses polytechniques, 2001, which has already been mentioned above.

To this end, the bridge 1 comprises a first movable element 7 linked to the mounting elements 5 via a first set of flexible joints 9a, 9b, a first pair of flexible joints 9a being linked by an intermediate element 11a and a second pair of flexible articulations 9b being linked by an intermediate element 11b in order to hyperguide the first mobile element 7 relative to the mounting elements 5. The shape and orientation of the articulations forming the first set of joints 9a are arranged so as to allow the first movable element 7 to move along a first axis Y. In the illustrated case, each pair of flexible joints 9a respectively 9b comprises two joints with four necks located one adjacent to each mounting element 5, each connecting a mounting element 5 to an intermediate element 11a, 11b, and the intermediate element 11a, 11b to the first movable element 7. The displacement of the first movable element 7 takes place substantially exclusively along this axis Y, displacements along a second perpendicular axis X being minimal (less than 1%, ideally less than 0.1% of displacements along the Y axis) . The exact shape of the flexible joints can be chosen from an almost infinite number of precise geometries known per se (neck, blade joints, etc.), and therefore should not be described in more detail here.

The bridge 1 also includes a second mobile element 13, which is linked to the first mobile element 7 by means of a second set of flexible articulations 15a, 15b arranged perpendicular to the first set of articulations 9a, 2b. Similarly, the individual joints of the second set of joints 15a, 15b are also linked in pairs 15a and 15b respectively by additional intermediate elements 17a and 17b respectively in order to hyperguidate the second mobile element 13 relative to the first mobile element 7 in the same way as described for the mounting elements 5 and the first mobile element 7. The shape and the orientation of these articulations are arranged so as to allow the second mobile element to move along the axis X, perpendicular to the 'Y axis.

The second movable element 13 of the bridge 1 supports the anchor 3 of the regulator, or any other timepiece which can benefit from an adjustment in the plane of the bridge 1. In the case of a "Genequand" escapement », The anchor is linked to a rigid part by flexible blades, this rigid part being secured to the second mobile element.

In order to make this adjustment, each of the first 7 and the second 13 mobile element has a slot 19, 21 respectively. Each slot 19, 21 is elongated along the axis perpendicular to the axis of movement of the corresponding movable element, namely along the axis X for the slot 19 provided in the first movable element 7, and along the axis Y for the slot 21 provided in the second movable element 13.

In use, the head of an eccentric 23, 25 takes place in the corresponding slot 19 and respectively 21. The foot 23a, 25a of each eccentric 23, 25 is mounted in rotation with fatty friction in a frame element of the clockwork movement so that a pivoting of the eccentric by means of an ad hoc tool causes a translation of the movable element 7, 13 corresponding along the axis Y, X respectively. In the case of an adjustment of the position of the first mobile element 7 along the Y axis, the second mobile element 13 is also moved because it is subordinate to the first mobile element 7. The eccentric being accessible perpendicular to the XY plane, it can easily be operated by the watchmaker without requiring disassembly of the bridge 1 and without requiring any special tool.

To allow this movement of the second movable member 13, its slot 21 is elongated substantially parallel to the axis Y so that it can slide on the eccentric 25. The slot 19 provided in the first movable member 7 is also elongated substantially parallel to the axis X, in order to be able to allow the geometric center of the head of the eccentric 23 to move along the slot 19 during adjustment of this eccentric 23.

Furthermore, the straight walls of the slots 19, 21 have been made flexible by making openings 27 parallel to said walls. These openings 27 allow the walls of the slots 19, 21 to deform slightly in response to a movement in the direction perpendicular to the slot 19, 21, which can happen, for example, in the event of an impact.

[0030] FIG. 2 illustrates a variant of a bridge 1 according to the invention, in which the bridge 1 serves as a balance bridge, and therefore directly supports a bearing 31 and a balance pin 29 indirectly via the bearing 31. Furthermore, the bridge 1 can act as a bearing in itself, for example by simply providing a hole intended to receive a pendulum axis, this hole functioning as a pierced stone. As such, it simply serves to support the pendulum pin 29.

The equivalent elements of the two illustrated embodiments bear the same reference signs. The principle of the bridge 1 remaining identical, only the differences compared to the embodiment of FIG. 1 will be described in detail below. A clearly visible difference in the geometry of the flexible articulations is that each pair of articulations forming a set of articulations 9a respectively 9b is located adjacent to the same mounting element 5, and not adjacent each to a different mounting element 5.

Since the bridge 1 must be subjected to shocks generated by the impact of the balance pin 29 on the bearing 31, the bridge is constructed in the form of an "X" in order to give it more rigidity than that of FIG . 1, the bearing 31 located between the mounting elements 5 in order to avoid twisting of the mobile elements during an impact. In the example illustrated, the shape of bridge 1 is asymmetrical, but a symmetrical shape is also possible.

Adjusting the position of the second movable element 13 in the XY plane makes it possible to adjust the position of the bearing 31 so that the balance pin 29 has a minimum of contact with the bearing 31 when the movement is in progress and is in a flat position. Consequently, the friction between the balance pin 29 and the bearing 31 can be minimized.

Furthermore, thanks to the sets of flexible articulations 9a, 9b, 15a, 15b, the second movable element 13 has a certain flexibility along all the axes X, Y and Z, the axis Z being perpendicular to the axes X and Y. The bearing can therefore be of the rigid type, comprising at least one of a pierced stone and a counter-pivot stone, the bridge 1 providing the elasticity to absorb shocks, without requiring any elastic element in the bearing 31.

The bridge 1 according to the invention can be manufactured from a plate of a micro-machinable material such as metal, amorphous, mono- or polycrystalline silicon, silicon oxide, alumina, diamond or the like. The plate may have a constant thickness, or may have more or less thick zones. Typically, this plate is micromachined by masking and engraving methods, dry or wet. Alternatively, if the plate is made of metal, it can be machined using wire EDM, or any other suitable method. These manufacturing processes are common in watchmaking and allow mass production of such bridges at a lower cost.

Claims (10)

1. Adjustable bridge (1) for a timepiece, comprising: - at least one mounting element (5) intended to be secured to a frame element of a watch movement; - a first mobile element (7) linked to said mounting element (5) by means of a first set of flexible articulations (9a, 9b) arranged to be able to allow the first mobile element (7) to move substantially the along a first axis (Y) relative to said mounting element (5); - a second mobile element (13) linked to said first mobile element (7) by means of a second set of flexible articulations (15a, 15b) arranged to be able to allow the second mobile element (13) to move substantially the along a second axis (X) relative to said first mobile element (7), said second axis (X) being perpendicular to said first axis (Y), said second mobile element (13) being arranged to support a timepiece (3 ; 31); characterized in that: - Said first movable element (7) comprises a first elongated slot (19) extending perpendicular to said first axis (Y) and in which is intended to take place a head of a first eccentric (23) mounted in rotation with fatty friction on a frame element of said watch movement; - Said second movable element (13) comprises a second elongated slot (21) extending perpendicular to said second axis (X) and in which is intended to take place a head of a second eccentric (25) mounted in rotation with fatty friction on a frame element of said watch movement. 2. Bridge (1) according to the preceding claim, wherein said bridge (1) is substantially planar and extends in a plane (XY) containing said first axis (Y) and said second axis (X). 3. Bridge (1) according to one of the preceding claims, wherein said bridge (1) is in one piece. 4. Bridge (1) according to one of the preceding claims, wherein at least one of the first mobile element (7) and the second mobile element (13) comprises at least one opening (27) extending parallel to said respective slot (19; 21) to allow deformation of the wall of said slot (19; 21). 5. Bridge (1) according to one of claims 1 to 4, wherein the bridge (1) comprises two mounting elements (5), the first set of flexible joints (9a, 9b) comprising two pairs of joints flexible, the two joints of each pair (9a; 9b) connecting one of the mounting elements (5) to the other and to the first movable element (7) via an intermediate element (11a; 11b) . 6. Bridge (1) according to one of claims 1 to 4, wherein the bridge (1) comprises two mounting elements (5), the first set of flexible joints (9a, 9b) comprising two pairs of joints flexible (9a; 9b), the two joints of each pair (9a; 9b) connecting one of the mounting elements (5) to itself and to the first movable element (7) via an intermediate element (11a; 11b). 7. Bridge (1) according to one of claims 5 and 6, wherein the second set of flexible joints (15a, 15b) comprises two pairs of flexible joints (15a; 15b), the two joints of each pair ( 15a; 15b) connecting the first mobile element (7) to itself and to the second mobile element (7) via an additional intermediate element (17a; 17b). 8. Clock movement including: - a frame, - a bridge (1) according to one of claims 1 to 7 secured to the frame by means of said mounting element (5); - a timepiece (3; 31) supported by said second movable element (13); - A first eccentric (23) comprising a head, said first eccentric (23) being mounted in rotation with fatty friction on an element of said frame and its head taking place in said first slot (19); - A second eccentric (25) comprising a head, said second eccentric (25) being mounted in rotation with fatty friction on an element of said frame and its head taking place in said second slot (21). 9. Movement according to the preceding claim, in which the timepiece element is chosen from: - a bearing (31); - a pendulum axis; - an anchor axis; - an axis of a mobile; - an anchor (3). 10. Shockproof device for a timepiece comprising a bridge (1) according to one of claims 1 to 7, said timepiece being a bearing (31) comprising at least one of a counterpivot stone and a stone breakthrough intended to receive a pendulum axis.