CH714107B1 - Piton holder for a mechanical watch movement. - Google Patents

Abstract

The invention relates to a stud holder (29) for a mechanical timepiece movement, which comprises a pair of lugs, namely a front lug (31) and a rear lug (32), jointly defining a notch in the lugs. (31, 32) being arranged so that a stud (35) can be held in the notch, characterized in that the rear tab (32) of the stud holder (29) comprises an extension (56) which defines, beyond the notch, an elbow (57) forming a retaining stop for the eyebolt (35) when said eyebolt (35) is extracted from the notch.

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

[0002] In most mechanical watches, the energy necessary for the rotation of the hands (eg minute and hour indicator hands) is accumulated and then dispensed by a sprung balance system, which includes a flywheel called balance, associated with a spring in the form of a ribbon wound in a spiral, called hairspring.

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).

[0004] 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 is detrimental to its behavior under load (and therefore to the precision of the watch movement); in addition, the fixing of the eyebolt by gluing is delicate on steel.

[0005] It is also known (although less common) to use silicon for the manufacture of the balance spring. 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 to be 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 escapement mechanism comprising an anchor driven by a low-amplitude oscillating movement, provided with two vanes 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).

[0007] In a traditional escapement mechanism, the oscillation frequency is approximately 4 Hz, or approximately 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 adjust 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 wrench mounted on a racket.

[0009] 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.

[0010] The assembly comprising the bridge, the racket, the key, the eyebolt holder, the eyebolt, the axle, the spring and the balance, is commonly referred to as a “regulating organ”. Examples of regulating organs are proposed by international application WO 2016/192957 and by European patent EP 2 876 504, both in the name of the watch manufacturer ETA.

[0011] Certain interventions on the regulating member may require unwinding (or even complete disassembly) of the hairspring. It is then necessary to separate the eyebolt, integral with the external 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.

[0013] However, it often 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 applied to it make it sufficiently ductile to allow the hairspring to be rewound.

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

[0016] The object of the invention is to allow spiteful use by limiting, or even eliminating, the risk of breakage.

Summary of the invention

[0017] It is proposed, first of all, a piton holder 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 relaxing during the spitefulness. The risk of the spring breaking is thus limited.

[0019] Advantageous characteristics of the eyebolt holder, which can be taken alone or in any technically possible combination, are defined in the dependent claims.

[0020] Secondly, an assembly comprising such a piton holder is proposed.

[0021] Advantageous characteristics of the assembly, which can be taken alone or in any technically possible combination, are defined in the dependent claims.

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

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

Brief description of the figures

Other objects and advantages of the invention will become apparent in the light of the description of an embodiment, given below with reference to the accompanying drawings in which: FIG.1 is an exploded perspective view partially showing a watch comprising a mechanical timepiece movement including a regulating member; FIG.2 is a perspective view from above showing the regulating member alone; FIG. 3 is a perspective view from below showing the regulating member; FIG. 4 is an exploded perspective view, from above, of the regulating member; FIG. 5 is an exploded perspective view, from below, of the regulating member; FIG. 6 is a perspective view of the eyebolt holder fitted to the regulating member of the preceding figures; FIG. 7 is a partial perspective view showing the eyebolt holder, the eyebolt (in dotted lines) mounted on the eyebolt holder, and part of the outer strand of the spring (also in dotted lines); FIG.8 is a perspective view similar to FIG.7, showing the eyebolt holder with the eyebolt extracted from the notch and in abutment against the elbow; FIG. 9 is a bottom view of the eyebolt holder alone; FIG. 10 is a bottom view of the eyebolt holder with, in dotted lines, the eyebolt snapped into the notch and, in solid lines, the eyebolt extracted from the notch, in abutment against the elbow.

Detailed description of the invention

In 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 includes, for wearing on the wrist, a bracelet 3 which is fixed on the middle part 2 between the lugs 4 formed projecting thereon.

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

[0029] The watch 1 comprises, finally, a watch movement 5, hereinafter simply called "movement", which comprises a plate 6 intended to be housed in the middle part 2 by being attached thereto, for example . by means of screws. The plate 6 forms a support for various mechanisms such as gear train, regulating member, escapement, transmission, timer, winder (non-exhaustive list).

This watch movement 5 is mechanical, its source of driving energy 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 on the plate 6. The bridge 8 forms both a support and a guide for the other components of the regulating organ 7.

According to an embodiment illustrated in the drawings, and in particular in FIG.1 and in 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 into helical engagement with a tapped hole 12 drilled in the plate 6.

The precise positioning of the bridge 8 relative to the plate 6 is provided by means of feet 13 which protrude 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 cantilever end thereof.

The regulating member 7 comprises, secondly, a main axis 17, which is in the form of a stepped monobloc part mounted in rotation relative to the bridge 8. More specifically, the main axis 17 is mounted in rotation between plate 6 and bridge 8.

According to a particular embodiment (illustrated in particular in 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 in 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.

[0039] The regulating member 7 comprises, thirdly, a spring 21 spirally wound around the main axis 17. More precisely, the spring 21, hereinafter referred to as the "spiral" has an internal end 22, integral with the axis 17, and an external coil 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.

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.

[0044] The regulating member 7 comprises, fifthly, a stud holder 29 which comprises a ring 30, by which it is secured to the bridge 8, and a pair of legs, namely a front leg 31 and a leg 32 rear (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 protrude radially from the ring 30 and, together, define a notch 33.

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

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

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

As illustrated in the drawings, and more particularly in 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 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 ensures the subjection (that is to say the immobilization with respect to the bridge 8) of the outer end 24 of the hairspring 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 main axis 17, 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 balance-spring 21 comes to a stop (with the axis 17 and the balance 25) then, under the effect of its elasticity, tends to compress to 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 are used to regulate the reciprocating tilting movements of the escape anchor, which is provided with a pair of paddles alternately attacking an escape wheel, the rotation of which is -pas, 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 an 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 relative to the latter around the main axis 17.

More specifically, the racket 39 comprises: a tail 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.

According to a preferred embodiment illustrated in particular in 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 tabs 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.

[0060] 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 of axis 17.

The stops 42 jointly form for the hairspring 21 a counting point, which 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 the oscillations) of the hairspring 21.

According to one embodiment illustrated in 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 55 graduation, as well as 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 (to magnifying glass or under a microscope, or by means of a specific device, such as the REGO model marketed by the company CENTAGORA) 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 removal of the pin 35 of the pin holder 29, may be necessary. To prevent the eyebolt 35 released from the eyebolt 29 from being thrown far under the effect of a sudden relaxation of the hairspring 21, the eyebolt 29 is provided with a retaining stop for the eyebolt 35 extracted from the 'notch 33.

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

Thus, the rear leg 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 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 squarely.

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

As can be seen clearly in 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 piton 35, transversely.

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

The eyebolt 35 snapped into the notch 33 is illustrated in dotted lines in FIG.7 and in 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 outward (that is to say tending to move the pin 35 away from the ring 30), in the direction indicated by the arrows in FIG. 7 and FIG. 10. However, 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 pin therefore tends to return there, and thus to wedge itself in the elbow 57 (and more precisely in the fillet 62) where it is thus retained, as illustrated in solid lines in FIGS. 8 and FIG. 10.

The elbow 57 (and therefore the stop that it forms) makes it possible to unclip the stud 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 release it completely from the eyebolt 29, eg. in order to remove the hairspring 21.

As the pin 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 of the pin 35 (eg by means of a pair of tweezers) for example to completely remove the hairspring 21, by a vertical movement, as illustrated by the arrow in FIG. 10. In other words, the spitefulness is carried out in two stages.

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

Claims (10)

1. Piton holder (29) for a mechanical clockwork movement (5), which comprises a pair of lugs, namely a front lug (31) and a rear lug (32), jointly defining a notch (33), the tabs (32, 33) being arranged so that a stud (35) can be held in the notch (33), characterized in that the rear tab (32) of the stud holder (29) comprises a extension (56) which defines, beyond the notch (33), an elbow (57) forming a retaining stop for the eyelet (35) when said eyelet (35) is extracted from the notch (33). 2. Piton holder (29) according to claim 1, characterized in that the extension (56) comprises a radial portion (59) and a transverse portion (60) which extends the radial portion (59) at right angles, the elbow (57) being defined at the junction between the radial portion (59) and the transverse portion (60). 3. Piton holder (29) according to claim 2, characterized in that the portion (60) transverse of the extension (56) is spaced from the tab (31) before to form with it a passage (61) transverse for the piton (35). 4. Piton holder (29) according to one of claims 2 or 3, characterized in that the rear tab (32) has a fillet (62) for internal connection at the elbow (57). 5. Assembly (7) for a movement (5) of mechanical clockwork, comprising a stud holder (29) according to one of the preceding claims and a stud (35), characterized in that the stud (35) has a cylindrical body (36) by which it is snapped into the notch (33), and, on either side of the body (36): - an enlarged head (37) by which the eyebolt (35) rests against the eyebolt holder (29), - a fork (38) in which an outer end (24) of a spring (21) of the movement (5) is intended to be housed. 6. Set (7) according to the preceding claim, further comprising a racket (39) which comprises two distinct integral elements, namely: - An upper element (45) (45) of the racket, which forms a pair of indexing fingers (43) making it possible to adjust the angular position of the racket (39); - A lower racket element (46) (46), which forms a tail (40). 7. Assembly (7) according to claim 6, characterized in that the upper element (45) comprises a central ring (47), the pair of indexing fingers (43) extending radially in a V from this central ring (47). 8. Assembly (7) according to one of claims 6 or 7, characterized in that the tail (40) comprises a pair of tabs (49) which define between them a slot (50) allowing the insertion of a key. (41). 9. Movement (5) of mechanical clockwork, which incorporates an assembly (7) according to one of claims 5 to 8. 10. Watch (1) comprising a mechanical clockwork movement (5) according to claim 9.