EP3451076B1 - Stud-holder for a mechanical clockwork movement - Google Patents

Description

Technical area

The invention relates to the field of watchmaking, and more particularly to the field of mechanical watchmaking, where the regulation of the driving energy is provided by a spring oscillator. More specifically, the invention relates to a pin holder for mechanical movement.

Technological background

In most mechanical watches, the energy necessary for the rotation of the hands (e.g. minute and hour indicator hands) is accumulated and then dispensed by a balance-spring system, which includes a flywheel called a balance, associated with a spring in the form of a ribbon wound in a spiral, called a spiral.

By an internal end, the hairspring is fixed on an axis integral in rotation with the balance; by an external end, the hairspring is fixed on a stud mounted on a stud holder itself integral with a fixed bridge (or cock).

Traditionally, the hairspring is made from a steel alloy based on cobalt, nickel and chromium. Quenching and tempering are commonly applied to this alloy, which has the advantage of giving it a high elastic limit and therefore good breaking strength. Another advantage of steel is its repairability. But one drawback of steel is its magnetisability, which affects its behavior under load. (and therefore to the precision of the watch movement); in addition, fixing the eyebolt by gluing is delicate on steel.

It is also known (although less frequent) to resort, for the manufacture of the balance-spring, to silicon. According to Vermot et al (Traite de Construction Horlogère, Presses Techniques et Universitaires Romandes, 2014, pp. 712-713 ), silicon has the advantage of having a low moment of inertia, a low coefficient of expansion, good resistance to corrosion and of being non-magnetic. In addition, it is possible to fix the eyebolt to the outer end of the silicon spring by means of a two-component glue activated by ultraviolet radiation, which offers a very high fixing power. However, the main drawback of silicon is its brittle nature, under the conditions described below.

The rotation of the balance is maintained - and its oscillations counted - by an escape mechanism comprising an anchor driven by a low-amplitude oscillating movement, provided with two paddles which attack the teeth of an escape wheel. Thus attacked, the escape wheel is imposed a step-by-step rotational movement, the frequency of which is determined by the frequency of oscillation of the anchor, itself fixed to the frequency of oscillation of the balance (c 'i.e. hairspring).

In a traditional escapement mechanism, the oscillation frequency is about 4 Hz, or about 28,800 vibrations per hour (Ah). One objective of good watchmakers is to ensure the isochronism and regularity of the oscillations (or constancy of the rate) of the balance.

It is known to regulate the rate of the balance by adjusting the active length of the hairspring, defined as the curvilinear length between its inner end and a counting point, located near the outer end of the hairspring and generally defined by a pair of stops carried by a key mounted on a racket.

In operation, this racket is fixed in rotation with respect to the axis of the hairspring. However, it is possible, by manual intervention, to finely adjust its angular position, e.g. by pivoting, by means of a screwdriver, of an eccentric acting on the racket in the manner of a cam.

The assembly comprising the bridge, the racket, the key, the eyebolt, the eyebolt, the axle, the spring and the balance, is commonly referred to as a “regulating organ”. Examples of regulating organs are proposed by the international application WO 2016/192957 and by the European patent EP 2 876 504 , both on behalf of the ETA watch manufacturer.

In addition, a piton holder is known from the document JP352023564U .

Certain interventions on the regulating organ may require unwinding (or even complete disassembly) of the hairspring. It is then necessary to separate the eyebolt, integral with the outer end of the balance spring, from the eyebolt holder.

This operation, called spitefulness, is delicate. The watchmaker usually grasps the eyebolt with a pair of tweezers, then gently removes it from the eyebolt holder.

However, it frequently happens that the eyebolt escapes the tweezers, which causes a sudden relaxation of the hairspring, the outer end of which is thus released.

This incident is of no consequence when the hairspring is made of steel (and more precisely of alloy steel, as indicated above), because the quenching and tempering treatments which are given to it applied make it sufficiently ductile to allow rewinding of the hairspring.

On the other hand, this same incident is dramatic for a silicon balance spring which, statistically, breaks in more than one in two cases.

The object of the invention is to allow spitefulness by limiting, or even eliminating, the risk of breakage.

Summary of the invention

Firstly, there is proposed an eyebolt as defined in claim 1.

In this way, the eyebolt extracted from the notch comes to be wedged in the stopper, which prevents the spring (hairspring) from suddenly slackening during spite. The risk of the spring breaking is thus limited.

Advantageous characteristics of the eyebolt, which can be taken alone or according to any technically possible combination, are defined in the dependent claims.

Secondly, an assembly is proposed comprising such an eyebolt holder.

Advantageous characteristics of the assembly, which can be taken alone or according to any technically possible combination, are defined in the dependent claims.

Thirdly, a timepiece movement comprising such an assembly is proposed.

Fourthly, a watch is proposed comprising such a mechanical clockwork movement.

Brief description of the figures

• La FIG.1 est une vue en perspective éclatée montrant partiellement une montre comprenant un mouvement d'horlogerie mécanique incluant un organe réglant ;
• La FIG.2 est une vue en perspective de dessus montrant l'organe réglant seul ;
• La FIG.3 est une vue en perspective de dessous montrant l'organe réglant ;
• La FIG.4 est une vue en perspective éclatée, de dessus, de l'organe réglant ;
• La FIG.5 est une vue en perspective éclatée, de dessous, de l'organe réglant ;
• La FIG.6 est une vue en perspective du porte-piton équipant l'organe réglant des figures précédentes ;
• La FIG.7 est une vue en perspective partielle montrant le porte-piton, le piton (en pointillés) monté sur le porte-piton, et une partie du brin externe du ressort (également en pointillés) ;
• La FIG.8 est une vue en perspective similaire à la FIG.7, montrant le porte-piton avec le piton extrait de l'encoche et en butée contre le coude ;
• La FIG.9 est une vue de dessous du porte-piton seul ;
• La FIG.10 est une vue de dessous du porte-piton avec, en pointillés, le piton encliqueté dans l'encoche et, en trait plein, le piton extrait de l'encoche, en butée contre le coude.

Other objects and advantages of the invention will emerge in the light of the description of an embodiment, given below with reference to the appended drawings in which:

• The FIG. 1 is an exploded perspective view partially showing a watch comprising a mechanical clockwork movement including a regulating member;
• The FIG. 2 is a perspective view from above showing the regulating member alone;
• The FIG. 3 is a perspective view from below showing the regulating member;
• The FIG. 4 is an exploded perspective view, from above, of the regulating member;
• The FIG. 5 is an exploded perspective view, from below, of the regulating member;
• The FIG. 6 is a perspective view of the eyebolt fitted to the regulating member of the preceding figures;
• The FIG. 7 is a partial perspective view showing the eyebolt holder, the eyebolt (dotted) mounted on the eyebolt, and part of the outer strand of the spring (also dotted);
• The FIG. 8 is a perspective view similar to the FIG. 7 , showing the eyebolt holder with the eyebolt extracted from the notch and in abutment against the elbow;
• The FIG. 9 is a bottom view of the piton holder alone;
• The FIG. 10 is a bottom view of the eyebolt holder with, in dotted lines, the eyebolt snapped into the notch and, in solid line, the eyebolt extracted from the notch, in abutment against the elbow.

Detailed description of the invention

On the FIG. 1 is shown a watch 1.

This watch 1 comprises a middle part 2, which can in particular be made of metal (eg steel), or a synthetic material (eg, a composite material comprising a polymer matrix loaded with fibers, typically carbon).

The watch 1 also comprises, for wearing on the wrist, a bracelet 3 which is fixed on the middle part 2 between lugs 4 protruding therefrom.

Watch 1 further comprises a crystal and a back (not shown), fixed to the middle part 2 on either side thereof.

The watch 1 comprises, finally, a watch movement 5, hereinafter simply referred to as “movement”, which comprises a plate 6 intended to be housed in the caseband 2 by being fixed thereto, for example. by means of screws. Plate 6 forms a support for various mechanisms such as cog, regulating member, escapement, transmission, timer, winder (non-exhaustive list).

This clockwork movement 5 is mechanical, its motive power source being provided by a barrel spring and regulated by a spring oscillator. To house this oscillator, movement 5 incorporates a regulating member 7, which is mounted on plate 6.

The regulating member 7 comprises, first of all, a bridge 8. This bridge 8, also called “cock”, is in the form of a rigid part (which may be metallic) fixed to the plate 6. The bridge 8 forms both support and guide for the other components of the regulating organ 7.

According to an embodiment illustrated in the drawings, and in particular in the FIG. 1 and on the FIG. 3 , the bridge 8 comprises a base 9. It is by this base 9 that the bridge 8 is fixed on the plate 6 by means of a screw 10 which, passing through a hole 11 made in the base 9, comes in helical engagement with a threaded hole 12 drilled in the plate 6.

The precise positioning of the bridge 8 relative to the plate 6 is ensured by means of feet 13 which project from an internal face of the base 9 and fit into complementary bores 14 made in the plate 6.

For fixing and guiding the other components of the regulating member 7, the bridge 8 comprises an apron 15, formed integrally with the base 9. The bridge 8 is provided with a bore 16 made in the apron. 15, at a cantilevered end thereof.

The regulating member 7 comprises, secondly, a main axis 17, which is in the form of a stepped one-piece piece mounted in rotation with respect to the bridge 8. More precisely, the main axis 17 is mounted in rotation between the plate 6 and bridge 8.

According to a particular embodiment (illustrated in particular on the FIG. 4 and FIG. 5 ), in order to ensure the rotation of the axis 17 relative to the bridge 8, the regulating member 7 comprises a shock absorber 18, driven into the bore 16, and which comprises, on an internal face, a hole 19 for guiding a first end of the main axis 17.

As seen elsewhere on the FIG. 1 , the plate 6 is provided with a hole 20 for guiding a second end of the main axis 17.

To limit friction during rotation of the main axis 17, the ends of the latter advantageously cooperate with a hard mineral, such as ruby or diamond.

The regulating member 7 comprises, in the third place, a spring 21 spirally wound around the main axis 17. More precisely, the spring 21, hereinafter called "hairspring", has an internal end 22, integral with the axis 17, and an external turn 23 which ends with an external end 24.

According to an advantageous embodiment, the hairspring 21 is made of silicon, optionally covered with an oxide layer.

When it is armed, the hairspring 21 provides a return torque which is exerted on the axis 17.

In order to increase this torque supplied by the hairspring 21 and the amplitude of its oscillations, the regulating member 7 comprises, fourthly, a flywheel in the form of a balance 25 integral in rotation with the axis 17.

This balance 25, produced for example. brass, includes a hub 26, by which it is driven on the axis 17, a rim 27, and spokes 28 (here three in number, but this number is only illustrative) which connect the hub 26 to serge 27.

The regulating member 7 comprises, in the fifth place, a stud holder 29 which comprises a ring 30, by which it is secured to the bridge 8, and a pair of tabs, namely a front lug 31 and a rear lug 32 (front and rear being defined in the direction of winding of the hairspring 21, from the inner end 22 to the outer end 24) which project radially from the ring 30 and, together, define a notch 33.

The eyebolt 29 is advantageously made of a metallic material, e.g. in steel.

According to an embodiment illustrated in FIG. 4 , the ring 30 of the pin holder 29 is driven onto a shank 34 which projects from the apron 15 coaxially with the bore 16.

The regulating member 7 comprises, in the sixth place, a stud 35 integral with the outer end 24 of the hairspring 21. This stud 35 is for example. made of steel. According to one embodiment, the eyebolt 35 is fixed to the outer end 24 of the hairspring 21 by bonding, by means of a photopolymerizable adhesive, the adhesion properties of which are activated by exposure to photon radiation in the ultraviolet. .

• une tête 37 élargie par laquelle le piton 35 est en appui contre le porte-piton 29,
• une fourche 38 dans laquelle est logée (en étant collée) l'extrémité 24 externe du spiral 21.

As illustrated in the drawings, and more particularly in the FIG. 4 , FIG. 5 , FIG.7 and FIG.8 , the pin 35 comprises a cylindrical body 36 by which the pin 35 is snapped into the notch 33, and, on either side of the body 36:

• an enlarged head 37 by which the eyebolt 35 bears against the eyebolt 29,
• a fork 38 in which is housed (by being glued) the outer end 24 of the hairspring 21.

Thus fixed on the eyebolt 29, the eyebolt 35 secures (that is to say the immobilization with respect to the bridge 8) of the outer end 24 of the balance spring 21.

The oscillations of the hairspring 21 are maintained (and counted) by an escape anchor (not shown) which communicates kinetic energy to it, which arms the hairspring 21 by driving it beyond its equilibrium position.

By disarming, that is to say by tending to regain its position of equilibrium, the hairspring 21 rotates the axis 17 main, which it is integral with its internal end 22, with the balance 25 which is itself integral with the axis 17. Having reached a complete relaxation, the hairspring 21 comes to a stop (with the axis 17 and the balance 25 ) then, under the effect of its elasticity, tends to compress again and then drives the axis 17 and the balance 25 in a rotation in the opposite direction.

The oscillations of the spiral system 21 - balance 17 serve to regulate the reciprocating tilting movements of the escape anchor, which is provided with a pair of paddles alternately attacking an escape wheel whose rotation step by step, at a frequency determined by the oscillations of the anchor (that is to say of the spring), is transmitted to a timer provided with one (or more) hand (s) indicating the hours (and / or minutes) .

The frequency of the oscillations of the spiral system 21 - balance 17 can be finely adjusted, by hand, by intervention on the regulating member 7, which comprises for this purpose, in the seventh place, a racket 39.

The racket 39 is fixed on the bridge 8 with the possibility of angular displacement with respect to the latter around the main axis 17.

• une queue 40 portant une clé 41 qui définit une paire de butées 42 disposées de part et d'autre de la spire 23 externe du spiral 21, et
• au moins un doigt 43 d'indexage qui coopère avec un excentrique 44, monté sur le pont 8 pour ajuster la position angulaire de la raquette 39 par rotation de l'excentrique 44.

More precisely, the racket 39 comprises:

• a shank 40 carrying a key 41 which defines a pair of stops 42 arranged on either side of the outer turn 23 of the hairspring 21, and
• at least one indexing finger 43 which cooperates with an eccentric 44, mounted on the bridge 8 to adjust the angular position of the racket 39 by rotation of the eccentric 44.

• Un élément 45 supérieur de raquette, qui porte le doigt 43 d'indexage ;
• Un élément 46 inférieur de raquette, qui porte la queue 40.

According to a preferred embodiment illustrated in particular on the FIG. 4 and FIG. 5 , the racket 39 comprises two distinct integral elements, namely:

• An upper racket element 45, which carries the indexing finger 43;
• A lower racket element 46, which carries the tail 40.

In the example illustrated, the upper element 45 comprises a central ring 47 and a pair of indexing fingers 43 which extend radially in a V from this central ring 47.

In this same example, the lower element 46 comprises a ring 48; the tail 40 comprises a pair of tongues 49 which project radially from the ring 48 and define between them a slot 50 in which the key 41 is inserted.

The central ring 47 of the upper element 45 comprises a projecting bush 51 driven into the ring 48 of the lower element, which secures the upper element 45 and the lower element 46.

Furthermore, the central ring 47 of the upper element 45 is provided with a chamfer 52 complementary to a conical bearing surface 53 formed on the shock absorber 18, which ensures the rotational guidance of the racket 39 around the axis 17.

The stops 42 jointly form for the hairspring 21 a counting point, which together with the internal end 22 defines an active (curvilinear) length on which depends the frequency of the oscillations of the hairspring 21. The (manual) rotation of the eccentric 44 varies. the angular position of the racket 39 and therefore of the counting point, which increases (or, conversely, decreases) the active length (and therefore the frequency of oscillations) of the hairspring 21.

According to an embodiment illustrated on FIG. 2 and FIG. 4 , the finger (s) is (are) housed in a recessed reserve 54 formed in the deck 15 of the bridge 8. A graduation 55, as well as the signs "-" and "+", engraved in the apron 15, provide the watchmaker with indications on the scale and the direction of rotation, useful to allow him to adjust finely (with a magnifying glass or a microscope, or even by means of a specific device, such as the REGO model marketed by the CENTAGORA company) the position of the eccentric 44 (notched for this purpose) - and therefore of the racket 39.

During manual interventions on the regulating member 7, the spite, that is to say the withdrawal of the eyebolt 35 from the eyebolt 29, may be necessary. To prevent the piton 35 released from the piton holder 29 from being thrown far under the effect of a sudden relaxation of the hairspring 21, the piton holder 29 is provided with a retaining stop for the piton 35 extracted from the 'notch 33.

More specifically, the rear tab 32 of the eyebolt 29 comprises an extension 56 which defines, beyond the notch 33, an elbow 57 forming this stop.

• Une section 58 intérieure, qui avec la patte 31 avant définit l'encoche 33,
• La prolongation 56, qui s'étend radialement dans la continuité de la section 58 intérieure.

Thus, the rear tab 32 comprises, in one piece:

• An interior section 58, which together with the front tab 31 defines the notch 33,
• The extension 56, which extends radially in continuity with the interior section 58.

According to an embodiment illustrated in the drawings, and more particularly in the FIG. 6 and FIG. 9 , the extension 56 comprises a radial portion 59 (substantially collinear with the inner section 58), and a transverse portion 60 which extends the radial portion 59 at right angles.

The elbow 57 is defined at the junction between the radial portion 59 and the transverse portion 60.

As we can clearly see on the FIG. 9 , the transverse portion 60 of the extension 56 is advantageously spaced from the front tab 31 to form with it a passage 61 wide enough to allow the introduction (or forced withdrawal) of the pin 35, transversely.

The rear tab 32 preferably has a fillet 62 for internal connection at the elbow 57.

The peg 35 snapped into the notch 33 is illustrated in dotted lines on the FIG. 7 and on the FIG. 10 . In this position, the body 36 of the pin 35 cooperates with the facets of the notch 33 which thus ensures its retention for the needs of the ordinary operation of the hairspring 21 (and therefore of the movement 5).

The pin 35 is extracted (that is to say clicked) from the notch 33 manually, by a radial movement outwards (that is to say tending to move the pin 35 away from the ring 30) , in the direction indicated by the arrows on the FIG. 7 and FIG. 10 . Now the equilibrium position of the hairspring 21 is reached when the eyebolt 35 is in the notch 33 of the eyebolt holder. During manual intervention, the eyebolt therefore tends to return there, and thus to wedge itself in the elbow 57 (and more precisely in the leave 62) where it is thus retained, as illustrated in solid lines on the FIG. 8 and FIG. 10 .

The elbow 57 (and therefore the stop that it forms) makes it possible to unclip the eyelet 35 without the risk of the latter escaping when it is extracted from the notch 31.

It is then possible to modify the grip of the eyebolt 7 to ensure a firmer hold and then completely disengage it from the eyebolt 29, for example. in order to remove the hairspring 21.

As the eyebolt 35 is then retained by the stop formed by the elbow 57, it is then possible to change the tool to ensure a more comfortable (and firmer) grip on the eyebolt 35 (eg by means of a pair of tweezers) with a view, for example, to completely dismantle the hairspring 21, by a vertical movement, as illustrated by the arrow on the FIG. 10 . In other words, the spitefulness is carried out in two stages.

This results in a reduced risk, or even eliminated, of breakage of the hairspring 21 during the spiteful operation, to the benefit of the reliability of the regulating member 7.

Claims (10)

1. Balance-spring stud-holder (29) for a mechanical timepiece movement (5), which comprises a pair of tabs, namely a front tab (31) and a rear tab (32), jointly defining a notch (33), the tabs (32, 33) being arranged in such a way that a balance-spring stud (35) can be held in the notch (33),
   characterised in that the rear tab (32) of the balance-spring stud-holder (29) comprises an extension (56) which defines, beyond the notch (33), a bend (57) forming a retaining abutment for the balance-spring stud (35) after said balance-spring stud (35) is extracted from the notch (33).
2. Balance-spring stud-holder (29) according to claim 1, characterised in that the rear tab (32) comprises an inner section (58) which, with the front tab (31), defines the notch (33), the extension (56) comprising a radial portion (59) substantially collinear with the inner section (58), and a transverse portion (60) which squarely extends the radial portion (59), the bend (57) being defined at the junction between the radial portion (59) and the transverse portion (60).
3. Balance-spring stud-holder (29) according to claim 2, characterised in that the transverse portion (60) of the extension (56) is spaced apart from the front tab (31) to form therewith a transverse passage (61) for the balance-spring stud (35).
4. Balance-spring stud-holder (29) according to one of claims 2 or 3, characterised in that the rear tab (32) has an inner connection hollow (62) at the level of the bend (57).
5. Assembly (7) for a mechanical timepiece movement (5), comprising a balance-spring stud-holder (29) according to one of the preceding claims and a balance-spring stud (35), characterised in that the balance-spring stud (35) has a cylindrical body (36) by which it is snap-fitted into the notch (33), and, on either side of the body (36):

   - a widened head (37) by which the balance-spring stud (35) bears against the balance-spring stud-holder (29),

   - a fork (38) into which an outer end (24) of a spring (21) of the movement (5) is intended to be housed.
6. Assembly (7) according to the preceding claim, further comprising a regulator (39) which comprises two distinct secured elements, namely:

   - an upper regulator element (45), which forms a pair of indexing fingers (43) making it possible to adjust the angular position of the regulator (39)

   - a lower regulator element (46), which forms a tail (40).
7. Assembly (7) according to claim 6, characterised in that the upper element (7) comprises a central ring (47), the pair of indexing fingers (43) extending in a V from this central ring (47).
8. Assembly (7) according to one of claims 6 or 7, characterised in that the tail (40) comprises a pair of tongues (49) which define between them a slot (50) allowing the insertion of a key (41).
9. Mechanical timepiece movement (5), which incorporates an assembly (7) according to one of claims 5 to 8.
10. Watch (1) comprising a mechanical timepiece movement (5) according to claim 9.

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