EP3118692B1 - Timepiece hairspring to hairspring-stud attachment by gluing - Google Patents

Description

Field of the invention

The invention relates to a sub-set of watches, comprising a pin arranged to be attached to a cock of a watch movement, said subassembly comprising a spiral spring comprising successively and in this order a spiral wound portion , an outer turn, a connection zone, and an end plate of section greater than that of said outer turn, said end plate ending in a distal end opposite said spirally wound portion, said peak comprising, between an inlet and an outlet, a housing which is arranged for, in a first free state of said subassembly, to enclose with play said end plate of said spiral spring with a tangential mobility in a tangential direction with respect to said external coil at said connection zone, and for, in a second immobilized state of said subassembly, immobilizing said end plate to which said housing is joined by a web of adhesive bonding them to one another, and in said second immobilized state, said layer of adhesive covers at least one shoulder of change of section of said end plate, and where, in said second immobilized state, said adhesive ply constitutes a mechanical seal of said spiral spring at least in a longitudinal direction of said housing substantially parallel to said tangential direction of said spiral spring, and said end plate comprises at least one eye communicating with said web in said second immobilized state.

The invention also relates to an oscillator comprising at least one such subset.

The invention further relates to an exhaust mechanism comprising at least one such subset.

The invention also relates to a watch comprising such an escape mechanism, and / or comprising at least one such subassembly.

The invention relates to the field of clock oscillator mechanisms comprising at least one elastic return means constituted by a spiral spring, and more particularly the case where such a spiral spring is made of silicon or silicon oxide, or DLC, or other similar micro-mechanical material made according to a "MEMS" method or the like.

Background of the invention

The invention is more particularly concerned with the attachment of the external part of the spiral spring, which in conventional clock oscillators, in particular with a balance spring, is generally attached to a stud itself attached to a cock.

The outer part of the spiral spring is usually glued in the piton. The bonding position is generally not very reproducible, because of the withdrawals of the glue which are not too. The quality of the bonding is difficult to control after execution, other than by destructive control performed on a sample. But, because of the low reproducibility of the bonding phenomena, even if the operation is fixed, that is to say with strictly controlled range parameters, there is no evidence that this sample is representative of the production. The risk is in a separation of the hairspring relative to the peak once the glue is frozen.

The use of a spiral spring having an end plate allows a relative improvement of the bonding, insofar as the use of a wafer more widely dimensioned than the turns of the spring makes it possible to have a contact surface of more important collage. Indeed, the strength of the bonding is not good when the section and the dimensions of the component to be bonded, here the spiral spring, decrease too strongly. The wafer is necessary to ensure a certain contact surface to the adhesive ply, which can allow a mechanical strength, which is essential since the chemical resistance alone can not guarantee the strength of the components to be assembled.

The document DE 23 33 446 A1 in the name of JUNGHANS GmbH describes a sprung balance, the outer end of the spiral spring is placed on a protruding portion of a plastic plate, and held in position by plasticization of this plastic material. The end of the spring can be placed in a slot in this protruding part, whose shoulders can be plasticized by ultrasonic welding. The attachment is improved with the cutting of a notch in an edge of the end of the spring in its attachment area. The welding is reversible, and can be removed during a repair, and traditional methods of bonding are possible.

Summary of the invention

The invention proposes to ensure a better service life of the connection between the pin and the wafer of the spiral assembled by gluing.

To achieve this, it is necessary to ensure that there is sufficient space between the end plate and its housing in the peak, so as to ensure a good flow of the glue in the housing, and thus , to obtain a better hold of the glued assembly.

The invention favors the use of a wafer called "shape", that is to say having a particular shape, optimized to ensure better mechanical strength of the bonded assembly, including traction. Thus, if it is necessary to reduce the dimensions of the end plate, the establishment of an end plate of appropriate shape ensures a good hold, even if the bonding contact surface is strongly scaled down.

For this purpose, the invention relates to a timepiece subassembly according to claim 1.

The invention also relates to an oscillator comprising at least one such subset.

The invention further relates to an exhaust mechanism comprising at least one such subset.

The invention also relates to a watch comprising such an escape mechanism, and / or comprising at least one such subassembly.

Brief description of the drawings

• la figure 1 représente, de façon schématisée, une section d'un sous-ensemble horloger selon l'invention, comportant un piton fixé à un coq, ce piton recevant, dans un logement qu'il comporte, une plaquette d'extrémité d'un ressort-spiral, la section étant représentée selon un plan sensiblement médian à cette plaquette d'une part, et à la dernière spire externe du ressort-spiral connexe avec cette plaquette, d'autre part. Cette plaquette comporte un oeil. Une nappe de colle remplit le logement du piton, remplit a totalité de cet oeil, et les ménisques d'extrémité formés par cette nappe de colle s'étendent, du côté intérieur du ressort-spiral, au-delà d'un épaulement formé au niveau d'une zone de raccordement entre la plaquette d'extrémité et la dernière spire externe du spiral, et, du côté le plus extérieur du ressort-spiral, au-delà de l'extrémité distale de ce ressort-spiral, selon une direction tangentielle par rapport à ladite spire externe au niveau de la zone de raccordement, de façon à ce que la plaquette d'extrémité soit entièrement entourée, dans toutes les directions, par la nappe de colle. La partie de la nappe de colle à l'intérieur de l'oeil forme une cheville d'arrêt opposant une grande résistance à l'arrachement ;
• la figure 2 représente une section d'un ressort-spiral dont la spire externe se termine par une boucle formant un oeil pour l'arrêt de la nappe de colle, cette boucle étant alors logée dans le logement du piton ;
• la figure 3 est une variante de la figure 1, d'encombrement plus réduit, où le ressort-spiral comporte, entre la spire externe et la plaquette d'extrémité, un épaulement extérieur qui n'est pas entouré par la nappe de colle, et où l'extrémité distale de la plaquette d'extrémité n'est pas non plus entourée par la nappe de colle, laquelle traverse entièrement un oeil de la plaquette d'extrémité pour immobiliser celle-ci ; cet épaulement extérieur est utile pour un ajustement du repère, optique ou mécanique, ou encore pour une visualisation ou un repérage de la longueur utile du spiral quand cette dernière est déterminée par un contact d'une zone de la spire externe avec une goupille ou similaire, l'épaulement extérieur permettant alors de mieux apprécier l'emplacement de cette zone de contact, et de calculer, si nécessaire, la longueur utile exacte ;
• la figure 4 est une section du logement vide du piton ;
• la figure 5 est un schéma-blocs illustrant une montre comportant un mouvement lequel intègre un oscillateur à ressort-spiral comportant un sous-ensemble selon l'invention.

Other features and advantages of the invention will appear on reading the detailed description which follows, with reference to the appended drawings, in which:

• the figure 1 represents, schematically, a section of a watchmaking subassembly according to the invention, comprising a stud fixed to a cock, this stud receiving, in a housing that it comprises, an end plate of a spring spiral, the section being shown in a substantially median plane to this plate on the one hand, and the last outer turn of the spiral spring connected with this plate, on the other. This wafer has an eye. A ply of glue fills the housing of the peak, fills all of this eye, and the end menisci formed by this layer of glue extend, on the inner side of the spiral spring, beyond a shoulder formed at a level of a connection zone between the end plate and the last outer turn of the hairspring, and, on the outermost side of the hairspring spring, beyond the distal end of this hairspring, in a direction tangential to said outer turn at the level of the zone of connection, so that the end plate is completely surrounded, in all directions, by the sheet of glue. The part of the adhesive ply inside the eye forms a stop pin opposing a high resistance to tearing;
• the figure 2 represents a section of a spiral spring whose outer turn ends with a loop forming an eye for stopping the adhesive ply, this loop then being housed in the piton housing;
• the figure 3 is a variant of the figure 1 , of smaller size, wherein the spiral spring comprises, between the outer coil and the end plate, an outer shoulder which is not surrounded by the adhesive layer, and where the distal end of the wafer the end is also not surrounded by the layer of glue, which passes entirely through an eye of the end plate to immobilize it; this outer shoulder is useful for an adjustment of the marker, optical or mechanical, or for a visualization or a marking of the useful length of the spiral when the latter is determined by a contact of a zone of the outer turn with a pin or the like , the outer shoulder then making it possible to better appreciate the location of this contact zone, and to calculate, if necessary, the exact effective length;
• the figure 4 is a section of the piton's empty dwelling;
• the figure 5 is a block diagram illustrating a watch comprising a movement which incorporates a spiral spring oscillator comprising a subassembly according to the invention.

Detailed Description of the Preferred Embodiments

The invention ensures a better in service of the connection between the pin and the plate of the spiral assembled by gluing, on the basis of a good mechanical strength, which is compensated for the chemical resistance which, alone, can not be sufficient to guarantee the holding of the components to be assembled, and in particular with regard to the tear resistance in the direction tangential to the outer turn of the spiral spring, where the return torque is applied. Once the layer of glue is fixed in the piton housing, the particular geometry of the plate must ensure this mechanical strength, and prevent its exit from the frozen block of glue.

For this purpose, the invention relates to a timepiece subassembly 100, comprising a pin 20 arranged to be fixed to a cock 40 of a clockwork movement 300. This subassembly 100 comprises a spiral spring 1.

This spiral spring 1 comprises successively and in this order a spirally wound portion, an outer turn 2, a connection zone 11, and an end plate 10 of section greater than that of the outer turn 2, the end plate 10 terminating at a distal end 12 opposite the spiral wound portion, and the connecting region 11 having a sectional change between the outer coil 2 and the end plate 10.

The peak 20 comprises, between an inlet 23 and an outlet 24, a housing 21 which is arranged for, in a first free state of the subassembly 100 to contain with play the end plate 10 of the spiral spring 1 with a mobility tangentially in a tangential direction T with respect to the outer turn 2 at the connection zone 11, and for a second immobilized state of the subassembly 100 to immobilize the end plate 10 to which the housing 21 is joined by a layer of glue 30 solidifying them to one another.

According to the invention, in the second immobilized state, the adhesive ply 30 covers at least one shoulder 5 for changing the section of the end plate 10.

In the particular non-limiting case of figure 1 the adhesive ply 30 also covers the connection zone 11. This arrangement only concerns applications where the point of definition of the active length of the spiral is situated on another zone of the outer turn 2 than the connection zone 11.

For the many usual applications where the connection zone 11 defines the active length of the hairspring, the variant of the hairspring is preferred. figure 3 . Indeed, if glue is to be deposited on the connection zone 11, the useful length of the spiral is changed, and therefore the frequency and the walking of the spiral are modified, which is not desired, it does not therefore no glue is required at the connection area 11.

And, in this second immobilized state, the ply 30 of adhesive constitutes a mechanical seal of the spiral spring 1 at least in a longitudinal direction L of the housing 21 substantially parallel to the tangential direction T of the spiral spring 1.

More particularly, as visible in the variant of the figure 1 in the second immobilized state, the ply 30 of adhesive covers the connection zone 11, and constitutes a mechanical seal of the spiral spring 1 at least in a longitudinal direction L of the housing 21 substantially parallel to the tangential direction T of the spiral spring 1.

The figure 1 shows a piton horizontally in the movement; of course the piton can be positioned vertically vertically, the benefit provided by the invention is the same.

Preferably, the housing 21 is large enough that the adhesive ply 30 completely surrounds at least a portion of the end plate 10, this part comprising one or more shoulders 5, 11 in the case of the sole figure 1 but not in the more general case of the figure 3 , and again at least one eye 6, with in the unstacked free state, sufficient clearance between the housing 21 and this particular part of the end plate 10 so that, after the deposition of the adhesive ply 30, that it surrounds this part of the wafer on all sides, so that the ply 30 of glue then constitutes a mechanical seal of the spiral spring 1 in the housing 21 in all degrees of freedom.

Advantageously, the housing 21 comprises at least one projecting or retracted volume arranged to form at least one stop of the adhesive ply 30, or comprises, on its inner walls 25, 26, grooves or notches, or is made with a coarse surface state, with a roughness Ra greater than 12 micrometers, so as to ensure a mechanical retention of the adhesive ply 30 In variants, the end plate 10 may comprise variable sections perpendicular to the longitudinal direction L.

In the figures 1 and 3 , the end plate 10 has an eye 6, and where the outer contour of the end plate 10 is of substantially constant cross-section, it is the cavity 6 which determines a resulting section smaller than that of the plate 10 outside the area of 6.

In a particular variant, the section of the end plate 10 can decrease, continuously and / or in stages, from its outer distal end 12 to the outer coil 2.

More particularly, as visible on the figure 3 , the end plate 10 has at least one shoulder 5 at which the section of the end plate 10 varies, this shoulder 5 being distinct from the connection zone 11 between the outer coil 2 and the end plate 10 and, in the second immobilized state, the adhesive ply 30 covers this shoulder 5, while the connection zone 11 remains external to the adhesive ply 30.

In a particular variant, and as visible in particular on the Figures 1, 2 and 3 , the end plate 10 comprises at least one eye 6, 8, communicating with the adhesive ply 30 in the second immobilized state.

More particularly, when the plate 10 includes such a stop 13, this eye 6, 8 is housed in the thickness of this stop 13 of maximum section of the end plate 10.

In the particular variant of figures 1 and 3 , the end plate 10 constitutes a loop 4 comprising at least one eye 6 in which the sheet 30, in the second immobilized state, penetrates only in an anchoring direction A substantially perpendicular to the tangential direction T.

In the particular variant of the figure 2 , the end plate 10 constitutes a hook 7 having at least one eye 8 open on the side of the outer coil 2, and having a fold 9 at its end farthest from the outer coil 2.

Different geometries of the end plate 10 are likely to be well suited to the implementation of the invention: or with protruding profiles in the form of a cross, of "L", with a cylindrical end, in the shape of a tee, with shoulders 5 forming surfaces perpendicular to the tangential direction and arranged to oppose a maximum tensile strength in this direction and to the spiral portion of the spiral spring 1, or again with reentrant profiles, not necessarily directly opposed, so not to weaken too much the end plate 10 by a too small section.

The invention is particularly suitable for fixing a spiral spring 1 of silicon and / or silicon oxide, or DLC, or other similar micro-mechanical material made by a "MEMS" method or the like.

The invention also relates to an oscillator 200 comprising at least one such subassembly 100.

The invention also relates to an escape mechanism 300 comprising at least one such subassembly 100.

The invention also relates to a watch 400 comprising such an escapement mechanism 200, or / and comprising at least one subassembly 100.

Claims (16)

1. Timepiece sub-assembly (100), comprising a balance spring stud (20) arranged to be fastened to a balance cock (40) of a timepiece movement, and said sub-assembly (100) comprising a balance spring (1), including in series and in order: a spiral wound part, an outer coil (2), a connection area (11), and an end plate (10) of larger section than that of said outer coil (2), said end plate (10) ending in a distal end (12) opposite to said spiral wound part, said balance spring stud (20) comprising, between an entry (23) and an exit (24), a housing (21) which is arranged, in a first free state of said sub-assembly (100), to loosely contain said end plate (10) of said balance spring (1) with tangential mobility in a tangential direction (T) with respect to said outer coil (2) in said connection area (11), and, in a second immobilised state of said sub-assembly (100), to immobilise said end plate (10) to which said housing (21) is joined by an adhesive layer (30) which secures said end plate and housing to each other, wherein, in said second immobilised state, said adhesive layer (30) covers at least one change-of-section shoulder (5) of said end plate (10), and wherein, in said second immobilised state, said adhesive layer (30) forms a mechanical seal for said balance spring (1) at least in a longitudinal direction (L) of said housing (21) substantially parallel to said tangential direction (T) of said balance spring (1), characterized in that said end plate (10) includes at least one eye (6; 8) communicating with said layer (30) in said second immobilised state.
2. Timepiece sub-assembly (100), according to claim 1, characterized in that said adhesive layer (30) covers at least one change-of-section shoulder (5) of said end plate (10) and does not cover said connection area (11).
3. Timepiece sub-assembly (100), according to claim 1, characterized in that, in said second immobilised state, said adhesive layer (30) covers said connection area (11).
4. Timepiece sub-assembly (100) according to claim 1, characterized in that said adhesive layer (30) forms a mechanical seal for said balance spring (1) in said housing (21) in all degrees of freedom.
5. Timepiece sub-assembly (100) according to claim 1, characterized in that said end plate (10) includes variable sections perpendicular to said longitudinal direction (L).
6. Timepiece sub-assembly (100) according to claim 5, characterized in that the section of said end plate (10) decreases, continuously and/or in steps, from said outer distal end (12) towards said outer coil (2).
7. Timepiece sub-assembly (100) according to claim 6, characterized in that said end plate (10) includes at least one said shoulder (5) where the section of said end plate (10) varies, said shoulder (5) being distinct from said connection area (11), and in that, in said second immobilised state, said adhesive layer (30) covers said shoulder (5), whereas said connection area (11) remains outside said adhesive layer (30).
8. Timepiece sub-assembly (100) according to claim 5, characterized in that said end plate (10) includes at least a first shoulder (5A) and a second shoulder (5B), where the section of said end plate (10) varies, said first shoulder (5A) and said second shoulder (5B) together delimiting a stop (13) of maximum section of said end plate (10), said first shoulder (5A) and said second shoulder (5B) being distinct from said connection area (11).
9. Timepiece sub-assembly (100) according to claim 8, characterized in that said first shoulder (5A) and said second shoulder (5B) are distinct from said distal end (12) of said connection plate (10).
10. Timepiece sub-assembly (100) according to claim 8, characterized in that said eye (6; 8) is housed inside said stop (13) of maximum section of said end plate (10).
11. Timepiece sub-assembly (100) according to claim 1, characterized in that said end plate (10) forms a loop (4) comprising at least one eye (6) in which said layer (30), in said second immobilised state, only penetrates in an anchoring direction (A) substantially perpendicular to said tangential direction (T).
12. Timepiece sub-assembly (100) according to claim 1, characterized in that said end plate (10) forms a hook (7) comprising at least one eye (8) open on the side of said outer coil (2), and including a bent portion (9) at the end thereof farthest from said outer coil (2).
13. Timepiece resonator (100) according to claim 1, characterized in that said balance spring (1) is made of silicon and/or silicon oxide.
14. Oscillator mechanism (200) including at least one sub-assembly (100) according to claim 1.
15. Escapement mechanism (300) including at least one sub-assembly (100) according to claim 1.
16. Watch (400) comprising one said escapement mechanism (300) according to claim 15 and/or including at least one sub-assembly (100) according to claim 1.

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