Horological device

Abstract

The invention relates to a watchmaking device (1) comprising a balance spring (4), a locking element (6), a stud (5) and a fixed or movable support (31) comprising a slot (11) extending parallel to the plane of the spring (4) and opening onto two opposite faces of the support (31) in the direction of the axis (A) of the spring (4), said stud (5) comprising a body (51, 52) arranged partly in the slot (11) and fixing the outer end (41) of the spring (4) on the side of the support (31) facing the spring (4) and a head (53) comprising a spherical surface arranged on the other side of the support (31) and axially retaining the stud (5) in the slot (11).When the locking element (6) is not in the locked position, the pin (5) can move in the longitudinal direction of the slot (11) and can pivot relative to the support (31) in three degrees of freedom to take a given position and orientation and when the locking element (6) is in the locked position, it presses the head (53) against the support (31) to lock the pin (5) in the said given position and orientation, the contact of the locking element (6) and the support (31) with the head (53) being made at the level of the spherical surface.

Description

[0001] The present invention relates to a watchmaking device comprising a fixed or mobile support, a balance spring, a locking element and a stud allowing the outer end of the spring to be fixed to the support, said support typically being a balance cock, a stud holder, a tourbillon cage or part of one of these elements.

[0002] In watch regulating organs, the hairspring is generally attached by its inner end to the balance shaft and by its outer end to the balance cock, i.e. to the balance bridge. The latter receives the stud, which is provided with a hole or a groove, into which the outer end of the hairspring is inserted. Different means of attachment can be used to fix the hairspring in the balance cock, such as welding, gluing, crimping, or tightening (by a set screw for example). The precision of the attachment of the hairspring to the balance cock is important so that its development is concentric.

[0003] Generally, hairsprings are supplied with the pins already attached. Sometimes the connection between the pin and the hairspring is defective, the hairspring is then subjected to stress during its attachment to the balance-cock and it does not have flat or concentric contractions.

[0004] Patent application FR 1 529 486 describes a stud for an escapement balance spring, the body of which, intended to be fixed to the balance-cock, comprises an orientable part, forming a ball joint, housed in a corresponding recess in the body of the stud and having an opening in which the outer end of the balance spring is fixed as well as means for blocking this orientable part, the whole being arranged in such a way as to allow the free orientation of the end of the balance spring and then its maintenance in a direction corresponding to the natural positioning of the latter. This stud is described as making it possible to avoid stresses on the balance spring and to guarantee that the turns are concentric. However, it has the disadvantage of having a complex structure with several parts to assemble and of only allowing limited freedom for the balance spring to take its natural shape.

[0005] In the Geneva hallmark, it is known to mount the stud in a groove made in the balance-cock, said groove being oriented radially relative to the axis of the hairspring. This groove in which the stud can slide freely, allows self-centering of the stud. In other words, regardless of the radial position of the stud in the balance-cock and the variability of the shaping or assembly of the hairspring, the stud automatically positions itself in the groove, at the distance from the pivot axis of the hairspring corresponding to its natural position. A holding plate is then added to the balance-cock to fix the stud by pressing it against the bottom of the groove. In this system, despite the natural radial positioning of the stud, the positioning in the plane of the end of the hairspring is not guaranteed. In other words, the hairspring is not necessarily in its natural (or resting) position.Indeed, there may be an inaccuracy at the bottom of the groove or a defect in the perpendicularity of the stud in relation to the hairspring. When the stud is clamped, via the tightening of the retaining plate, such a defect will be reflected in a stress on the hairspring, the end of which will be brought outside its general plane. Currently, when this happens, the terminal curve of the hairspring is corrected manually to try to restore the flatness of the hairspring, but this operation is delicate, even impossible when the hairspring is made of silicon.

[0006] An aim of the present invention is to propose a device comprising a stud, a support, a locking element and a hairspring allowing the outer end of the hairspring to be fixed to the support while generating the least possible stress or even no stress on the hairspring, even when the connection between the stud and the hairspring has defects, while remedying the aforementioned drawbacks.

[0007] It may also be desired to fix the outer end of the balance spring in a specific position, in particular to adjust the running characteristics of the balance spring and improve isochronism.

[0008] The invention proposes for these purposes a timepiece device comprising a balance spring, a locking element, a stud and a fixed or movable support comprising a slot extending parallel to the plane of the spring and opening onto two opposite faces of the support in the direction of the axis of the spring, said stud comprising a body arranged partly in the slot and fixing the outer end of the spring on the side of the support facing the spring and a head comprising a spherical surface arranged on the other side of the support and axially retaining the stud in the slot (in the direction of the axis of the spring). When the locking element is not in the locked position, the stud can move in the longitudinal direction of the slot and can pivot relative to the support in three degrees of freedom to take a given position and orientation.When the locking element is in the locked position, it presses the head against the support to lock the stud in said given position and orientation, the contact of the locking element and the support with the head being made at the level of the spherical surface.

[0009] Such a device has the advantage of allowing the stud to move in the longitudinal direction of the slot and to pivot relative to the support in three degrees of freedom to take a given position and orientation and then to fix it in said given position and orientation without repositioning or reorientation of the stud.

[0010] This typically allows the stud to be fixed in a configuration corresponding to the resting position of the hairspring to limit or even eliminate the stresses it is subjected to. This is also useful in the case where one wants to impose a specific position and / or orientation on the hairspring.

[0011] In a first embodiment of the invention, said given position and orientation are typically defined by the resting state of the hairspring and are imposed by the resting position of the hairspring, the one in which it is not subject to constraints. In this case, before the locking element is locked, the stud moves freely in the longitudinal direction of the slot and is freely oriented there.

[0012] In a second embodiment of the invention, the position of the stud in the longitudinal direction of the slot can be imposed by the watchmaker. The device according to the invention then typically comprises adjustment means making it possible to adjust the position of the stud in the longitudinal direction of the slot while leaving the orientation of the stud free prior to locking the locking element.

[0013] In a third embodiment of the invention, the position of the stud in the longitudinal direction of the slot and its orientation can both be chosen by the watchmaker before locking the locking element which will simply fix them.

[0014] Advantageously, the slot extends radially relative to the axis of the balance spring. It preferably opens radially on its outer side. This facilitates the placement of the stud in the slot. On its underside, the contour of the slot is preferably chamfered to facilitate the pivoting of the stud relative to the support.

[0015] In the context of the present invention, the head of the piton is typically in the form of a spherical cap with a height greater than the radius of its original sphere. The radius of the base circle of the spherical cap forming the head is typically less than the width of the slot.

[0016] The support is preferably selected from a balance bridge, a stud holder and a tourbillon cage. The support may also be a part of only one of these elements, for example a tourbillon cage plate.

[0017] Advantageously, the body of the stud comprises a base fixing the outer end of the hairspring and an intermediate portion, arranged in the slot, connecting the base to the head of the stud, the base forming a shoulder axially retaining the stud in the slot in the direction of the axis of the hairspring.

[0018] The intermediate portion is preferably in the shape of a cylinder of revolution. Its radius is typically equal to the radius of the base circle of the spherical cap forming the head of the piton.

[0019] Advantageously, the spiral of the device is made of a fragile material, i.e. one that does not have a plastic deformation domain, typically silicon. The invention is particularly advantageous in this case. Indeed, for spirals made of brittle material, adjustment or setting of the curvature by hand is not possible.

[0020] In addition, the piton has a simple structure, which makes it both easy to manufacture and assemble. It is typically metallic and preferably made of a single piece.

[0021] The invention also relates to a timepiece such as a wristwatch or a pocket watch comprising such a timepiece device.

[0022] Other characteristics and advantages of the present invention will appear on reading the following detailed description made with reference to the appended drawings in which: there figure 1 is a perspective view from above of a part of a watch mechanism incorporating a device according to a first embodiment of the invention, said device comprising in particular a balance wheel, a balance spring, a tourbillon cage comprising an upper plate and a lower plate connected by pillars as well as a locking element fixing the position of the stud in the upper plate of the tourbillon cage; figure 2 is a perspective view from above of part of the device of the figure 1 , in which the lower plate of the tourbillon cage, the pillars of said cage and the locking element are not shown; figure 3 is a perspective view from above of part of the device of the figure 1 , in which the tourbillon cage and the locking element are not shown; the figure 4 is a side view of a portion of the device shown in figure 1 , in which the lower plate of the tourbillon cage and the pillars of said cage are not shown; figure 5 is a perspective view, from below, of the device of the figure 1 centered on the peak; the figure 6 is a perspective view, from below, of the device of the figure 1 , centered on the stud, in which the spiral is not represented; the figure 7 is a side view of part of the device of the figure 1 as represented in the figure 6 .

[0023] In reference to the figures 1 And 7, a watch device 1 according to a first embodiment of the invention comprises a balance wheel 2, a tourbillon cage 3 comprising an upper plate 31 and a lower plate 32 connected by pillars 33, a balance spring 4, a stud 5 allowing the outer end 41 of the balance spring 4 to be fixed on the upper plate 31 and a locking element, here a cover 6. The upper and lower directions are defined with reference to the figures 1 et 2 .

[0024] The tourbillon cage 3 is intended to be mounted in a flying manner, for example by means of a ball bearing, on a frame 100, typically a plate or a bridge, of a watch mechanism.

[0025] The tourbillon cage 3 is intended to pivot, for example at a rate of one revolution per minute thanks to a drive wheel 7, corresponding to a second wheel, which is integral with it. The tourbillon cage 3 carries an escapement wheel (not illustrated) whose escapement pinion is intended to cooperate with a toothed wheel 8 belonging to the watch mechanism and fixed relative to the frame 100 of the watch mechanism.

[0026] The inner end of the balance spring 4 is fixed by means of a collet 9 on the balance staff 10, as illustrated in figure 3 The balance wheel 2 - balance spring 4 assembly is conventionally mounted to pivot around an axis of rotation (A) perpendicular to the plane defined by balance spring 4.

[0027] The stud 5 of the device 1 comprises a base 51, a head 53 and an intermediate portion 52 connecting the head 53 and the base 51. The base 51 comprises an opening 511 in which the outer end 41 of the balance spring 4 is fixed. The head 53 forms an articulation with the upper plate 31. It is in the form of a spherical cap whose height h ( figure 7 ) is greater than the radius r of the original sphere of the spherical cap. The intermediate portion 52 has a section smaller than that of the base 51 and that of the head 53. It is cylindrical of revolution. Its radius is equal to the radius a of the base circle of the spherical cap forming the head 53.

[0028] The upper plate 31 of the tourbillon cage 3 comprises a slot 11 in which the intermediate portion 52 of the stud 5 is intended to slide. The slot 11 extends radially relative to the axis (A). It is limited radially on the inner side by its inner wall and opens radially on the outer side so that it can receive the intermediate portion 52 of the stud 5 during the assembly of the device 1, without disassembly of the stud. The slot 11 allows the radial displacement of the stud 5 in a plane perpendicular to the axis (A) to allow the outer end 41 of the balance spring 4 to take the desired position. In the example illustrated, the outer end of the balance spring 4 is naturally positioned at the distance from the center of rotation of the balance spring 4 which is natural to it.

[0029] The upper plate 31 also comprises a hollow 12 into which the upper part of the slot 11 opens, said hollow 12 forming a housing intended to receive the head 53 of the stud 5 to form a connection with three degrees of freedom in rotation (ball joint type connection).

[0030] On its lower face, the contour 15 of the slot 11 is chamfered to facilitate the pivoting of the stud 5 relative to the upper plate 31. In the example illustrated, the stud 5 can theoretically pivot on itself at 360°, pivot in the axis of the slot 11 over an amplitude of approximately 60° and pivot perpendicular to the axis of the slot 11 over an amplitude of approximately 60°. In practice, the ranges of movement of the stud 5 will be limited by the balance spring 4.

[0031] The cover 6 is removable. Its role is to fix the position of the stud 5 relative to the tourbillon cage 3 after it has taken the desired position which corresponds in the example illustrated to that imposed by the balance spring 4 (natural or resting position). The cover 6, the head 53 and the hollow 12 are dimensioned so that the cover 6 can be fixed to the upper plate 31 so as to press the head 53 against the bottom of the hollow 12.

[0032] Prior to the installation of the cover 6, when the head 53 of the stud 5 is in the bottom of the hollow 12, bearing against the edges 13 defined by the upper edges of the slot 11, the stud 5 and the upper plate 31 form a connection comprising three degrees of freedom in rotation and one degree of freedom in translation. This type of connection is commonly referred to as a sphere-cylinder type connection or annular linear connection.

[0033] Thus, before the cover 6 is put in place, the device 1 allows the stud 5 to take the position and orientation imposed on it by the spiral 4.

[0034] The cover 6 is then screwed into the upper plate 31 of the tourbillon cage 3 by means of screws 14 so as to press the head 53 of the stud 5 into the bottom of the hollow 12, against the edges 13, and to immobilize the stud 5 relative to the upper plate 31 of the tourbillon cage 3. The cover 6 is then said to be in its locked position.

[0035] The whole is arranged so that, whatever the orientation of the stud 5 prior to the installation of the cover 6 (or as long as the cover 6 is not in its locked position), this is not modified by the installation of the cover 6. The installation of the cover 6 in its locked position does not require any reorientation of the stud 5 and therefore does not create tension in the balance spring 4. This is made possible thanks to the spherical surface of the head 53 and the fact that the contact of the cover 6 and the upper plate 31 with the head 53 is made at the level of the spherical surface.

[0036] Here, the piton 5 is a single piece, it is preferably metallic.

[0037] The relative dimensions of the stud 5 and the slot 11 (diameter d and length L of the intermediate portion 52 of the stud 5, width I of the slot 11, thickness e of the part of the upper plate 31 receiving the intermediate portion 52, radius r of the spherical cap, etc.) are all parameters that a person skilled in the art can adjust to guarantee a sphere-cylinder type connection as defined above prior to immobilizing the stud 5 via the fixing of the cover 6.

[0038] The installation of spiral 4 in device 1 includes the following steps: Provide a balance spring 4 whose outer end 41 is already fixed in the base 51 of the stud 5. Alternatively, the outer end of the balance spring 4 is introduced into the opening made in the base 51 of the stud 5 and then is fixed there by welding, gluing, crimping, or tightening. In the context of the present invention, the fixing of the balance spring 4 to the stud 5 is independent of that of the stud 5 on the upper plate 31 of the tourbillon cage 3; Fix the inner end of the balance spring 4 to the balance staff 10 by means of the collet 9 and place the intermediate portion 52 of the stud 5 in the slot 11 of the upper plate 31 of the tourbillon cage 3, with the head 53 in the hollow 12, in this order or the other; Let the stud 5 position itself and orient itself alone in the slot 11; Place the cover 6 on the upper plate 31 of the tourbillon cage 3 and fix it using the screws 14 in its locked position.

[0039] The tourbillon cage 3 is then mounted on the watch movement frame.

[0040] A device according to a second embodiment of the invention differs from the device 1 in that it comprises adjustment means making it possible to adjust the position of the stud 5 in the longitudinal direction of the slot 11 while leaving the orientation of the stud 5 free prior to placing the cover 6 in its locked position.

[0041] A device according to a third embodiment of the invention differs from the device according to the second embodiment of the invention in that it further comprises means allowing the watchmaker to orient the stud 5 as desired prior to placing the cover 6 in its locked position. It is possible to imagine manual positioning, possibly adapting the shape of the cover to access the head of the stud 5. The latter can be provided with a gripping extension (as for a joystick) allowing its positioning.

[0042] It will be clear to those skilled in the art that the present invention is in no way limited to the embodiments presented above and illustrated in the figures.

[0043] Typically, if in the illustrated example the hairspring is a Breguet hairspring, it is clear that the invention can be applied to other types of hairsprings, in particular to a flat hairspring.

[0044] In the example illustrated, the support on which the stud 5 is fixed is the upper plate 31 of a tourbillon cage 3 but the support could be different.

[0045] A support such as a tourbillon cage is a movable support. In the context of the present invention, the support could alternatively be a fixed support such as a balance cock or a piton holder or even only a part of one of these elements.

[0046] Furthermore, the cover 6 might not be removable but simply be tightened or loosened to move from an unlocked position in which it allows some movement of the stud 5 to a locked position in which the position and orientation of the stud 5 are locked.

[0047] Throughout the description, the terms upper and lower are used with reference to the position of the various organs in the figures 1 et 2. It is obvious that the orientation of the parts could be different when they are mounted in a watch mechanism.

[0048] In other variants, it is obvious that the shape of the organs can vary infinitely as long as its functions are ensured.

[0049] Whatever the embodiment of the invention, the device according to the invention makes it possible to fix the stud in given positions and orientations, chosen or imposed by the natural positioning of the outer end of the hairspring. In particular, the placement of the locking element in its locked position does not require any reorientation of the stud.

[0050] In the particular case where said position and orientation are left free, that is to say when they correspond to the state of rest of the hairspring, the device according to the invention makes it possible to fix the stud in a position in which the hairspring is in its state of rest and is not subject to stress. The outer end of the hairspring is naturally positioned at the distance from the center of rotation of the hairspring which is natural to it and according to the orientation in which it is not subject to stress and is then locked in this specific position and in this specific orientation by fixing the locking element on the support receiving the stud. Thus, the device according to the invention makes it possible to compensate for any defects existing in the connection of the hairspring to the stud and to obtain flat and concentric contractions.

Claims

1. A watchmaking device (1) comprising a balance spring (4), a locking element (6), a stud (5) and a fixed or movable support (31) comprising a slot (11) extending parallel to the plane of the balance spring (4) and opening onto two opposite faces of the support (31) in the direction of the axis (A) of the balance spring (4), said stud (5) comprising a body (51, 52) arranged partly in the slot (11) and fixing the outer end (41) of the balance spring on the side of the support (31) facing the balance spring (4) and a head (53) comprising a spherical surface arranged on the other side of the support (31) and axially retaining the stud (5) in the slot (11), the device (1) being characterized in that , when the locking element (6) is not in the locked position, the stud (5) can move in the longitudinal direction of the slot (11) and can pivot relative to the support (31) according to three degrees of freedom to take a given position and orientation and in that, when the locking element (6) is in the locked position, it presses the head (53) against the support (31) to lock the stud (5) in said given position and orientation, the contact of the locking element (6) and the support (31) with the head (53) being made at the level of the spherical surface.

2. Clock device (1) according to claim 1, characterized in that said given position and orientation are defined by the rest position of the hairspring (4).

3. Clock device (1) according to claim 1 or 2, characterized in that the slot (11) extends radially relative to the axis (A) of the balance spring (4).

4. Clock device (1) according to claim 3, characterized in that the slot (11) opens radially on its outer side.

5. Clock device (1) according to one of claims 1 to 4, characterized in thatsaid head (53) is in the form of a spherical cap with a height (h) greater than the radius of its original sphere and in that the radius (a) of the base circle is less than the width (1) of the slot (11).

6. Clock device (1) according to one of claims 1 to 5, characterized in that the support is a balance bridge, a stud holder, a tourbillon cage or part of one of these elements.

7. Clock device (1) according to one of claims 1 to 6, characterized in that the body of the stud (5) comprises a base (51) fixing the outer end (41) of the spiral (4) and an intermediate portion (52), arranged in the slot (11), connecting the base (51) to the head (53) of the stud (5), the base (51) forming a shoulder axially retaining the stud (5) in the slot (11).

8. Clock device (1) according to one of claims 1 to 7, characterized in that said intermediate portion (52) is in the shape of a cylinder of revolution.

9. Clock device (1) according to claim 8 when it depends on one of claims 5 to 7, characterized in that the radius of said cylinder of revolution is equal to the radius (a) of the base circle of the spherical cap forming the head (53) of the piton (5).

10. Clock device (1) according to one of claims 1 to 9, characterized in that the spiral (4) is made of a fragile material, typically silicon.

11. Clock device (1) according to one of claims 1 to 10, characterized in that the piton (5) is in one piece.

12. Timepiece such as a wristwatch or a pocket watch, characterized in that it comprises a clockwork device (1) according to one of claims 1 to 11.

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