EP3144741A1 - Adjustable bridge for timepiece - Google Patents

Abstract

Adjustable bridge (1) for a timepiece, comprising: - At least one mounting element (5) intended to be secured to a frame member of a watch movement; a first movable element (7) connected to said mounting element (5) via a first set of flexible hinges (9a, 9b) arranged to allow the first movable element (7) to move substantially the same along a first axis (Y) with respect to said mounting member (5); a second movable element (13) connected to said first movable element (7) via a second set of flexible hinges (15a, 15b) arranged to allow the second movable element (13) to move substantially the same along a second axis (X) with respect to said first movable member (7), said second axis (X) being perpendicular to said first axis (Y), said second movable member (13) being arranged to support a watch element (3) 31). According to the invention: said first movable element (7) comprises a first elongate slot (19) extending perpendicularly to said first axis (Y) and in which is intended to take place a head of a first eccentric (23) mounted in rotation with a fatty friction on a frame member of said watch movement; said second movable element (13) comprises a second elongate slot (21) extending perpendicularly to said second axis (X) and in which is intended to take place a head of a second eccentric (25) mounted in rotation with a fatty friction on a frame member of said watch movement.

Description

Technical area

The present invention relates to the field of watchmaking. It relates, more particularly, an adjustable bridge that adjusts the position of a watch element.

State of the art

The document FR759765 discloses an adjustable exhaust bridge along three axes, in order to be able to precisely determine the position of the cockpit which supports the axis of balance 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 portion of the bridge by means of a clamp or the like, which is extremely difficult to control for the watchmaker , and may require disassembly of the bridge. Adjusting the position of the cockroach is very difficult to perform.

The document CH34775 discloses an anchor escapement carrier 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 both sides of the slot. This setting is in one direction only, and is not suitable for two-axis adjustment.

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.

Among the most recent references, the document WO 2013/139807 describes several embodiments of adjustable bridges, each with its own disadvantages. For example, the embodiment of FIGS. 15 to 17 of this document comprises a bearing located at one end of a tongue cut in a plate. In order to adjust the position of the bearing, a pin or similar object is pushed into a groove surrounding the tongue to bend the tongue and thus obtain the desired position. Obtaining a precise adjustment is difficult and delicate. Indeed, the watchmaker must try several pins of different diameters. In addition, the adjustment of the position of the bearing is along a curve and is therefore not linear. Moreover, this arrangement does not allow precise adjustment along two perpendicular and independent axes. The embodiment of Figure 18 of this document provides more freedom of adjustment, but still requires the use of pins. Figure 8 illustrates another design, which allows only unidirectional adjustment, and is bulky and difficult to manufacture because of its non-planar structure.

The document EP 2,290,476 describes an isochronism corrector, in which some of the blades that the corrector comprises are adjustable by means of needles that bear against the sides of said blades. The use of such needles causes congestion in the height of the system, because they move perpendicular to the plane of the corrector during adjustment.

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

Disclosure of the 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 member of a watch movement, for example by means of screws, rivets, welding or the like. A first movable member is connected to said mounting member via a first set of flexible hinges arranged to allow the first movable member to move substantially along a first axis with respect to said mounting member, and a second movable member is connected to said first movable member via a second set of flexible hinges arranged to allow the second movable member to move substantially along a second axis with respect to said first member mobile, said second axis being perpendicular to said first axis, said second movable member being arranged to support a watch element.

According to the invention, the first movable element comprises a first elongated slot extending perpendicularly to said first axis and in which is intended to take place a head of a first eccentric mounted in frictionally rotational rotation on a frame member of said watch movement , and the second movable element comprises a second elongate slot extending parallel to said second axis and wherein is intended to take place a head of a second eccentric mounted in frictionally rotational rotation on a frame member of said watch movement.

An 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 one another. The use of eccentrics allows the adjustment to be performed by means of 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 tools or disassembly of the bridge, which would be particularly 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 monobloc, which simplifies its production by means of common micromachining processes.

Advantageously, at least one of the first movable element and the second movable element comprises at least one opening extending parallel to said respective slot to allow deformation of the wall of said slot. The slot can therefore catch any parasitic displacements and forces generated between the eccentric and the walls can be reduced in case of shock.

Advantageously, the bridge comprises two mounting elements, the first set of flexible hinges comprising two pairs of flexible hinges, the two hinges of each pair linking one of the mounting elements to the other and the first movable element by intermediate of an element intermediate. Alternatively, the bridge may comprise two mounting members, the first set of flexible hinges comprising two pairs of flexible hinges, the two hinges of each pair connecting one of the mounting members to itself and to the first movable member by through an intermediate element. The first movable member is, therefore, overstretched relative to the mounting members, minimizing any parasitic movement in an undesired direction. By "hyperguide" 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 polytechnic presses, 2001 .

Advantageously, the second set of flexible hinges comprises two pairs of flexible hinges, the two hinges of each pair linking the first movable element to itself and to the second movable element via an additional intermediate element. The second movable element is therefore also hyperguided with respect to the first.

The invention also relates to a watch movement comprising a frame, a bridge as described above secured to the frame via said mounting member, a watch element supported by said second movable member, a first eccentric comprising a head said first eccentric being mounted to frictionally rotated rotation on an element of said frame and its head taking up position in said first slot, and a second eccentric comprising a head, said second eccentric being rotated with a frictional friction on an element of said frame and its head taking place in said second slot.

The watch element can be chosen from a bearing, a balance shaft, an anchor axis, an axis of a mobile, or an anchor. The latter can for example be an anchor of a "Genequand" type of escapement that can be mounted rigidly to the bridge.

Finally, the invention relates to a shockproof device for a timepiece. This shockproof device comprises a bridge as described above, said watch element being a bearing comprising at least one of a counterpane stone and a pierced stone intended to receive a balance shaft.

Thanks to the flexibility provided by the flexible joints to the bridge, the bridge itself can function as an antilock, allowing not only a very precise positioning of the bearing and the reduction of friction linked thereto, but also the use of a rigid bearing, because the elasticity to make up for shocks is provided by the bridge.

Brief description of the drawings

• Fig. 1 illustre un premier mode de réalisation d'un système de réglage selon l'invention ; et
• Fig. 2 illustre un deuxième mode de réalisation d'un système de réglage selon l'invention.

Other details of the invention will appear more clearly on reading the description which follows, given with reference to the appended drawings in which:

• Fig. 1 illustrates a first embodiment of an adjustment system according to the invention; and
• Fig. 2 illustrates a second embodiment of an adjustment system according to the invention.

Embodiments of the invention

The figure 1 illustrates a first embodiment of an adjustable bridge 1 according to the invention. The bridge 1 serves as a support for a watch element 3. By "support" is meant not only "to wear" in the direction of an integral element of the bridge (for example a bearing), but also in the sense of "maintain in position ", Such as in the case of an axis of a mobile, a balance shaft, anchor or the like.

In the embodiment of this figure, the watch element 3 is an anchor of a "Genequand" type regulator 4, which is integral with the bridge 1. This type of regulator is described on the website http: // www .logistics-swiss.ch/homlomag/watch-articles/00232/new-exhaust- in a movement with a power reserve of 30 days and should not be described in more detail. Nevertheless, the same principle applies to a bearing, an axis of a conventional anchor, a balance shaft, an axis of a mobile or the like. By adjusting the position of the anchor parallel to the XY plane, it is possible to precisely adjust 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 member of a clockwork movement, by means of screws, solder or the like. It is also possible to envisage bridges which comprise only one mounting element 5, or which comprise more of them.

Bridge 1 is constructed as an XY table with flexible hinges extending in an XY plane. Such joints, also called "flexures" are formed by elastic blades or collars integral with the bridge 1. These joints, in comparison with a hinge joint, have no play, no friction, and therefore no hysteresis . A standard work on such articulations is the book Design of flexible guides, by Simon Henein, PPUR polytechnic presses, 2001 , which has already been mentioned above.

For this purpose, the bridge 1 comprises a first movable element 7 connected to the mounting elements 5 via a first set of flexible hinges 9a, 9b, a first pair of flexible hinges 9a being linked by an intermediate element 11a and a second pair of flexible hinges 9b being connected by an intermediate member 11b to hyperguider the first movable member 7 relative to the mounting members 5. The shape and orientation of the joints forming the first set of joints 9a are arranged to allow the first movable member 7 to move along a first axis Y. In the illustrated case, each pair of flexible joints 9a and 9b respectively comprises two four-necked joints located adjacent to each mounting member. 5, each connecting a mounting member 5 to an intermediate member 11a, 11b, and the intermediate member 11a, 11b to the first movable member 7. acement of the first movable element 7 is 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 hinges can be chosen from an almost infinite number of precise geometries known per se (collars, blades, etc.), and should not be described in more detail here.

The bridge 1 also comprises a second movable element 13, which is connected to the first movable element 7 via a second set of flexible joints 15a, 15b arranged perpendicularly to the first set of joints 9a, 9b. 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 hyperguide the second movable element 13 with respect to the first movable element 7 in the same manner as described for the mounting elements 5 and the first movable member 7. The shape and orientation of these joints are arranged to allow the second movable member 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 horological element that can benefit from an adjustment in the plane of the bridge 1. In the case of a "Genequand" exhaust, the anchor is connected to a rigid part by flexible blades, this rigid part being secured to the second mobile element.

In order to perform this adjustment, each of the first 7 and the second 13 movable 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 X axis for the slot 19 provided in the first movable element 7, and along the Y axis. 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 21 respectively. The foot 23a, 25a of each eccentric 23, 25 is mounted in frictionally rotational rotation in a frame member of the movement of clockwork so that a pivoting of the eccentric by means of an ad hoc tool causes a translation of the movable member 7, 13 corresponding along the axis Y, X respectively. In the case of an adjustment of the position of the first movable element 7 along the Y axis, the second movable element 13 is also displaced because it is sub-ordered to the first movable element 7. The eccentric being accessible perpendicular to the XY plane he can be easily maneuvered by the watchmaker without the need to dismantle the bridge 1 and without the need for a special tool.

In order to allow this displacement of the second movable element 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 element 7 is also extended substantially parallel to the X axis, in order to allow the geometric center of the head of the eccentric 23 to move along the slot 19 during an adjustment of this eccentric 23.

On the other hand, 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 displacement in the direction perpendicular to the slot 19, 21, which can happen for example in case of impact.

The figure 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 shaft 29 indirectly via the bearing 31. bridge 1 may act as a bearing in itself, for example by simply providing a hole for receiving a balance shaft, the hole functioning as a pierced stone. As such it simply serves as support for the balance shaft 29.

The equivalent elements of the two embodiments illustrated bear the same reference signs. The principle of the bridge 1 remaining identical, only the differences with respect to the embodiment of the figure 1 will be described in detail below. A noticeable difference in the geometry of the flexible joints is that each pair of joints forming a set of joints 9a and 9b, respectively, is adjacent to the same mounting member 5, and not each adjacent to a different mounting member 5.

Since the bridge 1 must undergo shocks caused by the impact of the balance shaft 29 on the bearing 31, the bridge is constructed in the form of "X" to give it more rigidity than that of the figure 1 , the bearing 31 located between the mounting elements 5 in order to avoid the torsion of the moving parts during a shock. In the illustrated example, the shape of the 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 shaft 29 has a minimum of contact with the bearing 31 when the movement is in motion and is located in a flat position. Therefore, the friction between the balance shaft 29 and the bearing 31 can be minimized.

Moreover, thanks to the flexible articulation sets 9a, 9b, 15a, 15b, the second movable element 13 has a certain flexibility along all the X, Y and Z axes, the Z axis being perpendicular to the X and Y axes. The bearing may therefore be of rigid type, comprising at least one of a pierced stone and a counter-pivoting stone, the bridge 1 providing the elasticity to cushion 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 silicon, mono- or polycrystalline, silicon oxide, alumina, diamond or the like. The plate may have a constant thickness, or may comprise more or less thick areas. Typically, this plate is micro-machined by masking and etching processes dry or wet. Alternatively, if the plate is metal, it can be machined by wire EDM, or any other suitable method. These manufacturing processes are common in the watch industry and make it possible to manufacture such bridges in series and at a lower cost.

Claims (10)

Adjustable bridge (1) for a timepiece, comprising: - At least one mounting element (5) intended to be secured to a frame member of a watch movement; a first movable element (7) connected to said mounting element (5) via a first set of flexible hinges (9a, 9b) arranged to allow the first movable element (7) to move substantially the same along a first axis (Y) with respect to said mounting member (5); a second movable element (13) connected to said first movable element (7) via a second set of flexible hinges (15a, 15b) arranged to allow the second movable element (13) to move substantially the same along a second axis (X) with respect to said first movable member (7), said second axis (X) being perpendicular to said first axis (Y), said second movable member (13) being arranged to support a watch element (3) 31); characterized in that said first movable element (7) comprises a first elongate slot (19) extending perpendicularly to said first axis (Y) and in which is intended to take place a head of a first eccentric (23) mounted in rotation with a fatty friction on a frame member of said watch movement; said second movable element (13) comprises a second elongate slot (21) extending perpendicularly to said second axis (X) and in which is intended to take place a head of a second eccentric (25) mounted in rotation with a fatty friction on a frame member of said watch movement. 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). Bridge (1) according to one of the preceding claims, wherein said bridge (1) is monobloc. Bridge (1) according to one of the preceding claims, wherein at least one of the first movable element (7) and the second movable element (13) comprises at least one opening (27) extending parallel to said slot ( 19; 21) to allow deformation of the wall of said slot (19; 21). Bridge (1) according to one of claims 1 to 4, wherein the bridge (1) comprises two mounting elements (5), the first set of flexible hinges (9a, 9b) comprising two pairs of flexible hinges, the two joints of each pair (9a; 9b) linking one of the mounting members (5) to the other and to the first movable member (7) via an intermediate member (11a; 11b) . Bridge (1) according to one of claims 1 to 4, wherein the bridge (1) comprises two mounting elements (5), the first set of flexible hinges (9a, 9b) comprising two pairs of flexible hinges ( 9a, 9b), the two joints of each pair (9a; 9b) linking one of the mounting members (5) to itself and to the first movable member (7) via an intermediate member (11a). 11 b). Bridge (1) according to one of claims 5 and 6, wherein the second set of flexible hinges (15a, 15b) comprises two pairs of flexible hinges (15a; 15b), the two joints of each pair (15a; 15b) linking the first movable member (7) to itself and the second movable member (7) via an additional intermediate member (17a; 17b). Clockwork movement comprising: - a frame, - A bridge (1) according to one of claims 1 to 6 secured to the frame via said mounting member (5); - a watch element (3; 31) supported by said second movable member (13); - a first eccentric (23) comprising a head, said first eccentric (23) being rotatably mounted frictionally 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 to rotate frictionally on an element of said frame and its head taking place in said second slot (21). Movement according to the preceding claim, in which the watch element is chosen from: - a bearing (31); - a balance shaft; - an anchor axis; - an axis of a mobile; - An anchor (3). Anti-shock device for a timepiece comprising a bridge (1) according to one of claims 1 to 7, said watch element being a bearing (31) comprising at least one of a counterpane stone and a pierced stone intended to receive a balance shaft.

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