EP2434353A1 - Anti-tripping hairspring for timepiece escapement - Google Patents

Abstract

The anti-tripping hairspring (1) has a blocking unit for blocking multiple turns (13), when rotation amplitude of the hairspring from balancing position to an extreme position attains determined angle. The unit has transversal segments (15) integrated to the turns, where the transversal segments are radial. The transversal segments are extended beyond two portions of a spiral (14), where the hairspring is made of silicon and metal. An independent claim is also included for a detect escapement of a timepiece comprising a tilting unit.

Description

The present invention relates to an anti-gallop hairspring for a clock escapement without stop, of the type escapement trigger.

The phenomenon of galloping is well known to those skilled in the art. It mainly concerns relaxation exhausts, and strongly harms when it occurs, to the precision of a timepiece that is equipped.

Escapement exhausts are particularly used in precision timepieces because they disturb the isochronism of the oscillator less than the Swiss anchor escapements. For a detailed description of such an escapement, refer to the book 'Théorie de l'horlogerie', chapter 6.7.1 .. We will confine ourselves here to recalling the principle of the gallop phenomenon of which it is the object.

In a detent escapement, the balance-balance oscillator oscillates between two extreme positions, a so-called 'high' position and a so-called 'low' position. Each of its oscillations comprises a so-called 'ascending' alternation, during which it moves from the low position to the high position, and a so-called 'downward' alternation, during which it switches from the high position to the low position. The escape wheel delivers to the oscillator sprung-balance, an oscillation pulse, during the upward alternation, in a position called 'equilibrium', substantially halfway between the high position and the low position. During the downward alternation, the sprung balance receives no impulse. It will be noted that the ascending and descending alternations are indifferently associated with the contraction or the radial extension of the hairspring.

The amplitude of each alternation, namely the angular displacement of the oscillator from the equilibrium position to the high or low position, is typically 330 °. During an impact, the sprung balance may receive an excess of energy and its amplitude exceeds this value, and even exceeds 360 °, a limit value beyond which the sprung balance receives an impulse. additional. The upward alternation can then count two pulses, while the downward alternation can count one. The escape wheel, which normally performs a step by oscillation, then performs two or even three steps during a single oscillation. This phenomenon of runaway sprung balance, which self-maintains, is called gallop. It hinders the precision of the movement, because for each additional step made by the escape wheel, the measurement of the time advance of a duration inversely proportional to the oscillation frequency of the balance spring.

Various locking mechanisms exist to remedy the gallop of the sprung balance. These mechanisms are designed to block the rotational movement of the sprung balance beyond a given angle of 330 °. One of them, described in the application EP 1 801 669 , comprises a pinion integral in rotation of the sprung balance. Said pinion meshes with a toothed sector, pivotally mounted, and provided with two terminal spokes may abut against a fixed stop if the rocker is driven beyond a given angle of rotation. This device proves effective to prevent the oscillator from racing, and this in both directions of rotation, nevertheless it generates losses at the level of the gearing between the pinion and the toothed sector, which disturb the isochronism of the sprung balance. Another mechanism disclosed in the application EP 1 645 918 comprises an arm, mounted radially on the last turn of the spiral, which is interposed between a finger integral with the balance beam and two columns mounted on a balance bridge, when the balance spring exceeds a certain angular and radial extension. This device is difficult to implement, mainly because of the extreme precision required for its assembly.

The present invention provides a simple and robust alternative to existing anti-gallop devices. More specifically, it relates to an anti-gallop hairspring for a clock escapement, intended to oscillate between two extreme positions, passing through an equilibrium position, and comprising a plurality of turns. According to the invention, it further comprises means for locking at least two consecutive turns when its amplitude of rotation from the equilibrium position to at least one of the extreme positions reaches a determined angle ψ.

In an advantageous embodiment, these means comprise transverse segments, integral with consecutive turns, offset angularly to abut against each other when the rotation of the spiral according to the invention, from said position of balance to at least one of the extreme positions, reaches a certain angle ψ.

Thanks to these transverse segments, the hairspring is braked or blocked in its rotation without the use of external means likely to disturb its isochronism.

The present invention also relates to a clock escapement provided with such an anti-gallop spiral.

• les figures 1 et 2 sont des vues de dessus d'un premier mode de réalisation d'un spiral anti-galop selon l'invention, respectivement en position d'équilibre et en position de blocage,
• la figure 3 illustre une variante de ce premier mode de réalisation d'un tel spiral,
• la figure 4 représente une forme avantageuse du premier mode de réalisation d'un spiral anti-galop selon l'invention, en position de blocage,
• la figure 5 est une vue de détail du spiral représenté en figure 4,
• les figures 6 et 7 sont des vues de dessus d'un deuxième et d'un troisième modes de réalisation d'un spiral anti-galop selon l'invention, configuré pour réaliser un blocage en contraction,
• les figures 8 et 9 illustrent ces mêmes deuxième et troisième modes de réalisation du spiral anti-galop selon l'invention, configuré, cette fois, pour réaliser un blocage en extension, et
• la figure 10 représente un spiral anti-galop selon l'invention réunissant les caractéristiques des modes de réalisation 7 et 9.

Other features and advantages of the present invention will emerge from the description which follows, made with reference to the accompanying drawings, and giving by way of explanatory example, but in no way limiting, some advantageous forms of producing an anti-hairspring. gallop for timepieces, drawings in which:

• the Figures 1 and 2 are views from above of a first embodiment of an anti-galling hairspring according to the invention, respectively in the equilibrium position and in the locking position,
• the figure 3 illustrates a variant of this first embodiment of such a spiral,
• the figure 4 represents an advantageous form of the first embodiment of an anti-gallop hairspring according to the invention, in the blocking position,
• the figure 5 is a detail view of the spiral represented in figure 4 ,
• the Figures 6 and 7 are views from above of a second and a third embodiment of an anti-gallop hairspring according to the invention, configured to achieve a contraction lock,
• the Figures 8 and 9 illustrate these same second and third embodiments of the anti-gallop hairspring according to the invention, configured, this time, to achieve a blockage in extension, and
• the figure 10 represents an anti-gallop hairspring according to the invention combining the features of embodiments 7 and 9.

The anti-gallop spiral represented at equilibrium in figures 1 , 3 , 6, 7 , 8, 9 and 10 and referenced as a whole 1, is formed generally of a blade 10 wound on itself in spiral, so as to have an angular elasticity. The central end 11 of the blade 10 is fixed in a known manner on a shell 20 driven on a balance shaft 21, while its peripheral end 12 is intended to be fixed to a not shown cock. From one end to the other, the hairspring 1 comprises a plurality of turns 13, typically between 10 and 15, having between them, in equilibrium, a pitch p.

According to the invention, the spiral 1 further comprises a plurality of transverse segments 15, 15 ', 15 "a, 15" b, 15 "c secured to successive turns 13, and arranged angularly to abut one on the other, when the amplitude of rotation of the hairspring 1 exceeds a determined angle ψ between 300 ° and 360 °, from its equilibrium position to one of its extreme positions.

In the embodiment presented in Figures 1 to 5 , the hairspring 1 is formed, from the central end 11, of a first spiral portion 14a of connection to the ferrule 20, then of a succession of spiral portions 14 of pitch p, connected together by transverse segments 15 of length l, and finally, of a last spiral portion 14b of connection to a rooster. Preferably, the segments 15 extend radially, but, alternatively, they may be slightly inclined relative to the radial orientation. By construction, the initial radius of a spiral portion 14 is equal to the final radius of a preceding portion 14 increased by the length l of a segment 15. The successive transverse segments 15 are arranged angularly to abut one against the other when the amplitude of the alternation associated with the contraction of the hairspring 1 reaches a determined value ψ of between 300 ° and 360 °.

To this end, the various parameters of the balance spring 1, in its equilibrium position, are linked by geometric relations explained below. N is the number of turns 13 of the hairspring 1, from the central end 11 to the peripheral end 12, R _n the radius of the nth turn 13, R ₁ and R _N , respectively the radii of the first and of the last turn 13. We note still θ _n the angular offset at equilibrium, with respect to the radially aligned position, between the transverse segments 15 associated respectively with the nth and n + 1th turns 13, and Φ _n the angular sector of the nth spiral portion 14.

It is known that the amplitude of rotation of the hairspring 1, from its equilibrium position to one of its extreme positions, is not distributed uniformly over all the N turns 13, the turns 13 of large radius absorbing a greater part of the amplitude of rotation than the turns 13 of small radius. It can be shown that for a rotation amplitude of the spiral 1 given, each turn 13 is deformed by an angle proportional to its radius R _n . It follows that the radial segments 15, associated respectively with the nth and n + 1th turns, are aligned radially when the amplitude associated with the contraction of the hairspring 1 takes the determined value ψ, if the angular offset θ _n between them, at 1 balance, obeys the relationship: $${\mathrm{\theta }}_{\mathrm{not}}\mathrm{=}\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}$$

The angular sector Φ _n of an nth spiral portion 14 is the complement of the angular offset θ _n between the radial segments 15 respectively associated with the nth and n + 1th turns 13. It therefore obeys the following relation: $${\mathrm{\Phi }}_{\mathrm{not}}\mathrm{=}360-\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}$$

For example, for a number of turns equal to 10, as illustrated in Figures 1 and 2 , and an angle ψ equal to 320 °, there are 11 portions of spirals 14 and 12 radial segments 15. The angular offsets θ _n between radial segments vary from 16 °, from the central end 11, to 41 ° at the end 12, while the angular sectors Φ _n spiral portions 14, from 344 ° to 319 °.

Finally, so that two consecutive segments 15 abut against each other when the amplitude of the alternation reaches the determined value ψ, it is necessary that their length l is sufficient. As is known to those skilled in the art, the pitch p of a hairspring 1 decreases, when it contracts, by a value which depends on the amplitude of the alternation and the number N of turns 13. segments 15 therefore contact if the length l of the segments 15 satisfies the relation: $$\mathrm{2}\mathrm{p}\mathrm{>}\mathrm{l}\mathrm{\ge }\mathrm{p}$$

When the preceding rules of construction are applied, the transverse segments 15 abut one against the other beyond a determined rotation angle en, as shown in FIG. figure 2 . The turns 13 are then locked in rotation relative to each other and the hairspring 1 has no or almost no angular elasticity. Its rotation movement is suddenly blocked. The galloping phenomenon is thus avoided in the alternation associated with the contraction of the hairspring 1. This alternation will preferably be the upward alternation, since the phenomenon of galloping occurs more frequently during this alternation.

et d'une troisième portion de spirale 14b, de secteur angulaire quelconque. Les trois portions de spirale 14 sont raccordées entre elles par deux segments transversaux 15, venant en butée l'un contre l'autre lorsque l'angle déterminé ψ est atteint. Dans ce cas, seules deux spires consécutives se bloquent en rotation relativement l'une à l'autre, freinant ainsi le mouvement général de rotation du spiral 1, au lieu de le bloquer. Une telle variante du premier mode de réalisation est illustré en figure 3. Par extension, le spiral 1 peut comporter deux, trois et jusqu'à N' portions de spirale 14, et, respectivement, trois, quatre et jusqu'à N'+1 segments transversaux 15, N' étant fonction du nombre N de spires 13 et de l'angle ψ. Le freinage du spiral 1 augmente avec le nombre de portions de spirale 14 et de segments transversaux 15, jusqu'au blocage complet du spiral lorsque le nombre de portions de spirale 14 prend la valeur maximum N'.It should be noted here that it may be sufficient to brake the rotation of the hairspring 1 in case of shock, rather than blocking it. In this case, the spiral 1 is formed, at least, of a first spiral portion 14a of any angular sector, of a second spiral portion 14 of angular sector Φ _n = 360 $$-\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}},$$

and a third spiral portion 14b, of any angular sector. The three spiral portions 14 are interconnected by two transverse segments 15 abutting one another when the determined angle ψ is reached. In this case, only two consecutive turns lock in rotation relatively to one another, thus slowing the general movement of rotation of the spring 1, instead of blocking it. Such a variant of the first embodiment is illustrated in figure 3 . By extension, the hairspring 1 can comprise two, three and up to N 'portions of spiral 14, and, respectively, three, four and up to N '+ 1 transverse segments 15, N' being a function of the number N of turns 13 and the angle ψ. The braking of the hairspring 1 increases with the number of spiral portions 14 and transverse segments 15, until complete locking of the hairspring when the number of spiral portions 14 takes the maximum value N '.

We now refer to Figures 4 and 5 , which represent an advantageous form of the embodiment of the spiral 1 illustrated in FIG. Figures 1 and 2 . According to this variant, the segments 15 extend radially slightly beyond the two spiral portions 14 that they connect, and comprise two fingers 16 and 17 at their ends, extending angularly towards the outside of the spiral portions 14 that they connect. As shown in detail in figure 5 , the fingers 16 and 17 fit into each other when the segments 15 abut. The segments 15 are then locked radially relative to each other, which gives the hairspring 1, in addition to an angular rigidity, a radial rigidity, when the determined amplitude ψ is reached. The locking spiral 1 is ensured even during violent shocks, because the radial elasticity does not compensate, in this case, the angular rigidity.

In Figures 6 and 7 , there is shown, respectively, a second and a third embodiment of the spiral 1 according to the invention.

The spiral 1 illustrated in Figures 6 and 7 , differs from the embodiment described with regard to Figures 1 and 2 , in that it is formed of a single spiral portion 14, from the central end 11 to the peripheral end 12, which are secured to the transverse segments 15 'and 15 "a and 15" b.

tandis que le secteur angulaire Φ_n les séparant est de 360 $$-\frac{\mathrm{\Psi }}{\mathrm{N}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{n}}}{{\mathrm{R}}_{\mathrm{N}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}\mathrm{.}$$

Lorsque la rotation du spiral 1 selon l'invention dépasse la valeur critique ψ lors de l'amplitude associée à sa contraction, les segments 15' s'alignent radialement et viennent en butée les uns contre les autres. Le spiral 1 est alors bloqué en rotation.According to the first variant represented at equilibrium figure 6 , the transverse segments 15 'are of length l greater than or equal to p and less than or equal to 2p, and are integral with the single spiral portion 14 by their middle. They extend substantially radially, but, alternatively, may also be slightly inclined relative to the radial orientation. In this case, the inclination must be chosen so as not to block the return to equilibrium of the hairspring 1, if the determined angle ψ is exceeded. At equilibrium, the angular offset θ _n between the transverse segments 15 'respectively associated with the nth and n + 1th turns 13, is worth, as stated previously, $$\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}},$$

while the angular sector Φ _n separating them is 360 $$-\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}\mathrm{.}$$

When the rotation of the hairspring 1 according to the invention exceeds the critical value ψ during the amplitude associated with its contraction, the segments 15 'align radially and abut against each other. The hairspring 1 is then locked in rotation.

According to the variant represented at equilibrium figure 7 , the hairspring 1 comprises first transverse segments 15 "a and second transverse segments 15" b, integral with the single spiral portion 14 by one of their ends. The first transverse segments 15 "are pointing outwardly of the hairspring 1, while the second transverse segments 15" b point inwardly of the hairspring 1. Both are of length l greater than or equal to p / 2, less than p.

et le secteur angulaire Φ_n les séparant est égal à 360 $$-\frac{\mathrm{\Psi }}{\mathrm{N}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{n}}}{{\mathrm{R}}_{\mathrm{N}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}\mathrm{.}$$

Lorsque la rotation du spiral 1 selon l'invention dépasse la valeur déterminée ψ lors de l'amplitude associée à sa contraction, les segments 15"a viennent buter contre les segments 15"b. Le spiral 1 est alors bloqué en rotation.Each turn 13, with the exception of the first and the last, has a transverse segment 15 "a and a transverse segment 15" b. The first turn 13 from the central end 11, has a single transverse segment 15 "oriented outwardly, while the last has only 15" b, facing inwards. The transverse segments 15 "a are aligned radially along a radius of the hairspring 1 and the transverse segments 15" b are offset with respect to the segments 15 "a by an angle θ _N. The offset θ _n between a segment 15" has associated with an nth turn 13 and a segment 15 "b associated with an n + 1st turn 13, is worth, as previously, $$\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}$$

and the angular sector Φ _n separating them is equal to 360 $$-\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}\mathrm{.}$$

When the rotation of the hairspring 1 according to the invention exceeds the determined value ψ during the amplitude associated with its contraction, the segments 15 "abut against the segments 15" b. The hairspring 1 is then locked in rotation.

As mentioned above, the transverse segments 15 'and 15 "a and 15" b are at least two in number, for a braking effect of the hairspring 1, and not for locking. It will also be noted that, in an advantageous variant, the segments 15 'and 15 "a, 15" b of the spiral 1 described opposite Figures 6 and 7 , comprise fingers 16 and 17 extending angularly and intended to fit into each other to give a radial rigidity spiral 1 in the angular locking position. This effect has already been described above with regard to figures 3 and 4 .

We have previously described embodiments of an anti-gallop hairspring 1 for locking during the alternation associated with its contraction. Generally, this is positive alternation, because the galloping phenomenon occurs preferably during this alternation. However, it can happen that the positive alternation is associated with the extension of the spiral. In this case, it is desired that the locking of the hairspring take place in extension and not in contraction. The Figures 8 and 9 illustrate a particular configuration of the spirals 1 represented in Figures 6 and 7 , allowing this effect.

mais le secteur angulaire Φ_n les séparant est égal à 360 + $$\frac{\mathrm{\Psi }}{\mathrm{N}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{n}}}{{\mathrm{R}}_{\mathrm{N}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}\mathrm{.}$$

De plus, le pas p d'un spiral 1 augmente, lorsqu'il s'étend radialement, d'une valeur qui dépend de l'amplitude de l'alternance et du nombre N de spires 13. La longueur l des segments transversaux 15' doit alors être prévue pour qu'ils se contactent lors de l'alternance associée à l'extension. A titre indicatif, on donne la relation suivante : $$\mathrm{l}\mathrm{\approx }\mathrm{1.6}\mathrm{p}$$

The spiral 1 represented in figure 8 differs from the spiral 1 described next to the figure 6 , in that the transverse segments 15 'are arranged to block it when the amplitude of its rotation exceeds a critical value ψ in extension and not in contraction. The principle of operation is identical, but the rules of construction are different. In particular, the equilibrium angular offset θ _n between two transverse segments 15 'associated respectively with the nth and n + 1th turns 13, is well worth $$\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}},$$

but the angular sector Φ _n separating them is equal to 360 + $$\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}\mathrm{.}$$

In addition, the pitch p of a hairspring 1 increases, when it extends radially, by a value which depends on the amplitude of the alternation and the number N of turns 13. The length l of the transverse segments 15 'must then be provided for them to contact each other during the alternation associated with the extension. As an indication, we give the following relation: $$\mathrm{l}\mathrm{\approx }\mathrm{1.6}\mathrm{p}$$

Thanks to these characteristics, each segment 15 'abuts against a consecutive segment 15' when the amplitude of rotation of the hairspring 1 reaches a determined angle ψ in extension, and the rotation of the hairspring 1 is thus blocked.

, mais le secteur angulaire Φ_n les séparant est égal à 360 + $$\frac{\mathrm{\Psi }}{\mathrm{N}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{n}}}{{\mathrm{R}}_{\mathrm{N}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}\mathrm{.}$$

La longueur l des segments 15"a et 15"c est typiquement égale à 0.8p. Lorsque l'amplitude de rotation du spiral 1 atteint la valeur déterminée ψ en extension, les segments 15"a viennent buter contre les segments 15"c, et le spiral est alors bloqué en rotation.In the same way, the spiral 1 illustrated in figure 9 differs from the spiral 1 described next to the figure 6 , in that it comprises segments 15 "a and 15" c designed to block its rotation in extension and not in contraction. The transverse segments 15 "are aligned along a radius of the spiral 1. The segments 15" c point, like the transverse segments 15 "b, towards the inside of the spiral 1, but they are distinguished by their position relative to the segments 15 "a. The offset θ _n between a segment 15 "associated with an nth turn 13 and a segment 15" c associated with an n + 1 turn 13, is as before $$\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}$$

, but the angular sector Φ _n separating them equals 360 + $$\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}\mathrm{.}$$

The length l of segments 15 "a and 15" c is typically 0.8p. When the amplitude of rotation of the hairspring 1 reaches the determined value ψ in extension, the segments 15 "abut against the segments 15" c, and the hairspring is then locked in rotation.

Lorsque l'amplitude de rotation du spiral ainsi configuré atteint l'angle déterminé ψ, en contraction ou en extension, les segments 15"a viennent buter respectivement contre les segments 15"b ou 15"c.We now refer to the figure 10 representing a hairspring 1 intended to lock in extension and contraction when its amplitude of rotation reaches a determined value ψ. Said spiral 1 combines the characteristics of the spiral 1 represented in figure 7 and the spiral 1 shown in figure 9 . It comprises first segments 15 "a, second segments 15" b and third segments 15 "c positioned relatively to each other in the manner described previously described, the transverse segments 15" are thus aligned along a radius of the spiral 1 and the transverse segments 15 "b and 15" c are offset on either side of the segments 15 "a of an angle θ _n equal to $$\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}\mathrm{.}$$

When the amplitude of rotation of the spiral thus configured reaches the determined angle ψ, in contraction or extension, the segments 15 "abut respectively against the segments 15" b or 15 "c.

The spiral 1 according to the invention is made of a material having elastic properties. Preferably, because of its discontinuous structure, it will be chosen to manufacture silicon, by a photolithographic process well known to those skilled in the art. Alternatively, one can opt for a metal spiral, for example nickel, gold, or a nickel alloy and gold, obtained by a physico-chemical deposition process type liga.

Claims (19)

Anti-gallop spiral (1) for a watch escapement, intended to oscillate between two extreme positions, through an equilibrium position, and comprising a plurality of turns (13), characterized in that it comprises, in addition means (15, 15 ', 15 "a, 15" b, 15 "c) for locking at least two consecutive turns (13) when its rotation amplitude from the equilibrium position to at least one extreme positions, reaches a certain angle ψ. Anti-gallp spiral (1) according to claim 1, characterized in that said means comprise at least two transverse segments (15, 15 ', 15 "a, 15" b, 15 "c), integral with two consecutive turns (13 ), angularly offset in the equilibrium position to abut against each other when the rotation of the balance spring (1) from said equilibrium position to at least one of the extreme positions, reaches a determined angle ψ. Anti-gallp spiral (1) according to claim 1, characterized in that said means comprise a plurality of transverse segments (15, 15 ', 15 "a, 15" b, 15 "c), integral with a plurality of turns (13) consecutive, angularly offset in the equilibrium position to abut against each other when the rotation of the balance spring (1) from said equilibrium position to at least one of the positions extremes, reaches a certain angle ψ. Anti-gallp spiral (1) according to one of claims 2 and 3, characterized in that said transverse segments (15, 15 ', 15 "a, 15" b, 15 "c) are radial. Anti-gallop spiral (1) according to one of claims 2 to 4, characterized in that it comprises N turns (13) of increasing radius R ₁ to R _N , and in that the angular offset θ _n to the equilibrium between a transverse segment (15, 15 ', 15 "a) associated with an nth turn (13) and a transverse segment (15, 15', 15 "b, 15" c) associated with an n + 1th turn (13), is equal to $$\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}},$$

where R _n is the radius of the nth turn (13). Anti-gallop spiral (1) according to claim 5, characterized in that the angular sector Φ _n from a transverse segment (15, 15 ', 15 "a) associated with an nth turn (13) to a transverse segment ( 15, 15 ', 15 "b) associated with an n + 1 th turn (13) is equal to $$\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}\mathrm{.}$$

Anti-gallop spiral (1) according to claim 5, characterized in that the angular sector Φ _n from a transverse segment (15 ', 15 "a) associated with an nth turn (13) to a transverse segment (15' , 15 "c) associated with an n + 1th turn (13) equals 360+ $$\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}}$$

Anti-gallop spiral (1) according to one of claims 5 and 6, characterized in that it is formed of a plurality of spiral portions (14) of pitch p, of angular sector Φ _n equal to 360- $$\frac{\mathrm{\Psi }}{\mathrm{NOT}}\mathrm{\cdot }\frac{{\mathrm{R}}_{\mathrm{not}}}{{\mathrm{R}}_{\mathrm{NOT}}\mathrm{-}{\mathrm{R}}_{\mathrm{1}}},$$

interconnected by said transverse segments (15). Anti-gallp spiral (1) according to claim 8, characterized in that it is of pitch p, and in that said transverse segments (15) are of length l between p and 2p. Anti-gallop spiral (1) according to claim 9, characterized in that it further comprises two connecting spiral portions (14a, 14b). Anti-gallop spiral (1) according to one of claims 2 to 7, characterized in that it is formed of a single spiral portion (14) of which said transverse segments (15 ', 15 "a, 15 "b, 15" c). Anti-gallop spiral (1) according to claim 11, characterized in that it is of pitch p, and in that said transverse segments (15 ') are of length l between p and 2p, and are integral with the turns ( 13) by their middle. Anti-gallp spiral (1) according to claim 11, characterized in that it is of pitch p, and in that said transverse segments (15 "a, 15" b, 15 "c) are of length l between / 2 and p, and are integral with said turns (13) at their ends. Anti-gallp spiral (1) according to claim 13, characterized in that said transverse segments (15 "a, 15" b, 15 "c) comprise first segments (15" a) pointing outwardly of the spiral (1 ), and second segments (15 "b, 15" c) pointing inwardly of the spiral (1). anti-galling spiral (1) according to one of claims 1 to 14, characterized in that it is formed of silicon. Anti-gallop spiral (1) according to one of claims 1 to 14, characterized in that it is formed of metal according to a liga type process. Clock escapement comprising an oscillating member provided with a hairspring according to one of claims 1 to 16. Clock escapement according to Claim 17, characterized in that it has no stop. Clock escapement according to claim 18, characterized in that it is of the expansion type.

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