EP3255510B1 - Calender and method for calendering a timepiece barrel spring - Google Patents

Description

Field of the invention

The invention relates to a method of calendering the spiral portion of a watch-spring, from a lace drawn and pre-rolled, said lace comprising, successively, from a beginning of the blade, a shell shaped beforehand calendering, with a curvature whose center is on an outer side of said lace, said shell being followed by a neck having a zone of zero curvature and forming a zone of inflection, and said neck being followed by a zone of accumulation which is intended to be, during said calendering operation, spirally calendered in a curvature whose center is an inner side of said lace, opposite said outer side, said accumulation zone ending in a tape end.

The invention relates to the field of manufacture of clock springs.

Background of the invention

The manufacture of clock springs is complex, and requires many steps, including a step of ringing and / or a calendering step of a portion of a lace at one end of which has been previously formed a shell, to form the leaf of the spring.

This calendering operation is delicate, and requires perfect reproducibility. The handling of the spring is inconvenient at the exit of the calendering operation.

The document CH708674A2 in the name of General Ressort describes a device for shaping a wire during a method of manufacturing a mainspring, comprising a wire drive system in two directions opposite to each other. other, and comprising a device for guiding and ejecting the wire; the equipment also includes a calendering device in the first direction with reference to the drive system, a shovel device in the second opposite direction, and a central wire guide arranged at the drive system for cooperate with at least one of the calendering and shearing devices to deform the wire.

The document WO2008 / 102388A1 in the name of Boldrini Spa describes a calender comprising a support carrying two rollers and a pressure roller which, in cooperation with each other, define a curved feed path for a bending plate. The rollers are movable relative to the pressure roll to vary at least one curvature value of the feed path. The apparatus further comprises a pair of articulated kinematic mechanisms, each of which acts on a respective roller to move it along a plurality of trajectories located in a plane transverse to the axis of rotation of the roller.

Summary of the invention

The purpose of the calendering is to guarantee the functioning of the spring. Indeed, the entire leaf spring must provide the maximum torque when disarming the spring. That is, for each location on the blade, the spring surface is constrained to its elastic limit in the fully-armed state.

The invention proposes to modify the calendering so as to avoid a conventional and expensive operation, ring setting the spring for the end of its development, for example for the execution of a treatment. And, more particularly, to produce a storable intermediate product that can be handled flat.

The invention must make it possible to avoid unnecessary loading of processing facilities with bulky tools, and to facilitate handling of the springs while eliminating the usual debugging.

The calendering process consists of constraining the spring blade between two rollers and a motorized rod to make a three-point bending of the blade, to deform plastically.

The calendering is usually done at a constant diameter, which involves a stack of turns, which can not return to their flattened shape once out of the plane. This problem is all the more important as the diameter of the spring is small.

The invention proposes the implementation of a progressive or variable calendering technique, which makes it possible to produce a calendered spring with a space, constant or variable depending on the settings, between the turns. The goal is to facilitate handling in subsequent operations of the manufacturing process, and to remove the usual mattress. The invention makes it possible to guarantee a calender of smaller diameter at the calendered portion which corresponds to the beginning of the process, and to increase the diameter while approaching the shell.

The principle of the invention also consists in constraining the blade between three points to exceed the elastic limit locally in the blade and thus form the calendered portion.

To this end, the invention relates to a method of calendering a mainspring according to claim 1.

Brief description of the drawings

• la figure 1 représente, de façon schématisée, et en plan, un ressort de barillet d'horlogerie calandré selon le procédé de l'invention ;
• la figure 2 représente, de façon schématisée, et en vue de dessus, une calandre utilisée pour la mise en oeuvre du procédé selon l'invention avec un lacet introduit pour son calandrage ;
• la figure 3 représente, de façon similaire à la figure 2, la mise en contact du lacet avec trois moyens d'appui et de guidage répartis de part et d'autre de ce lacet ;
• la figure 4 représente, de façon similaire à la figure 3, la mise en pression du moyen d'appui et de guidage intermédiaire, sur le lacet;
• la figure 5 représente, de façon similaire à la figure 4, un autre angle d'enfilage du lacet dans la calandre ;
• la figure 6 représente, de façon schématisée, la déformation du triangle de contact entre les trois moyens d'appui et de guidage et le lacet, lors de l'avancée du moyen d'appui et de guidage intermédiaire par rapport aux deux extrêmes.

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 schematically represents, in plan, a calendered clock spring according to the method of the invention;
• the figure 2 represents, schematically, and in plan view, a calender used for carrying out the method according to the invention with a lace introduced for its calendering;
• the figure 3 represents, similarly to the figure 2 contacting the lace with three bearing and guiding means distributed on either side of this lace;
• the figure 4 represents, similarly to the figure 3 pressurizing the intermediate support and guide means on the lace;
• the figure 5 represents, similarly to the figure 4 another angle of threading of the lace in the shell;
• the figure 6 represents, schematically, the deformation of the contact triangle between the three support and guide means and the lace, during the advancement of the support means and intermediate guide with respect to the two extremes.

Detailed Description of the Preferred Embodiments

The invention relates to a method of calendering the spiral portion of a clock spring 100 watchmaking, from a lace 1 drawn and pre-rolled.

This lace 1, of thickness "e", comprises successively, since a blade start, a shell 2 shaped prior to calendering, with a curvature whose center is an outer side of the lace 1.

This shell 2 is followed by a neck 3, of length LC, having a zone of zero curvature 4 and forming a zone of inflection.

And this neck 3 is followed by an accumulation zone 5, which alone relates to the calendering operation according to the invention, and which is intended to be, during this calendering operation, calendered in a spiral according to a curvature of which the center is an inner side of the lace 1, opposite to the outer side.

The accumulation zone 5 terminates in a strip end 6, and may advantageously, but not necessarily, include a short final LF non-spiral length, which constitutes the primer by which the calendering operation is started.

According to the invention, the operation is a variable calendering operation, and more particularly a progressive calendering operation.

According to the invention, a calender 20 is used which comprises at least a first support and guide means 10 arranged to exert a force F on the yaw 1 in a first intermediate contact zone A, which is situated between a second B and a third C extreme contact zones that comprise respectively a second 12 and a third 13 support and guiding means, which comprises the calender 20, for winding the accumulation zone 5 with a curvature opposite to that of the shell 2.

And, during the advance of the lace 1 in the calender 20, the position of the first contact zone A is gradually changed away from the second B and third C contact zones, to vary the calender radius since a first minimum value R1 to a second maximum value R2 at the junction between the accumulation zone 5 and the neck 3, where the calendering operation is stopped.

The figure 3 illustrates the contacting of the lace 1 with the three bearing and guiding means 10, 12, 13, distributed on either side of this lace 1, at the beginning of the calendering, the figure 4 illustrates the pressurization of the support and intermediate guide means 10, on the lace 1. And the figure 6 represents the deformation of the contact triangle ABC between the three bearing and guiding means 10, 12, 13, and the lace 1, during the advancement of the intermediate support and guide means 10 with respect to the two extremes 12 and 13.

In a particular implementation of the invention, the third support and guiding means 13 are maintained in a fixed position.

In a particular embodiment of the invention, the second support and guiding means 12 are maintained in a fixed position.

In a particular embodiment of the invention, the first support and guiding means 10 are moved relative to the second 12 and third 13 support and guiding means which are fixed.

In a particular embodiment of the invention, the first support and guiding means 10 and / or the second support and guiding means 12 are moved relative to the third support and guiding means 13 which is in a fixed position.

In a particular embodiment of the invention, a carriage 11 carrying the first support and guiding means 10 is displaced, with at least one degree of freedom, to exert this force F on the lace 1.

And, more particularly, it prints to this carriage 11 a forward movement, including regular, allowing the progressive calendering according to the invention. The Figures 3 and 4 illustrate a particular non-limiting embodiment with a pivoting of the carriage 11, which allows to show a particular deformability of the triangle ABC supports.

In a particular embodiment of the invention, a deflector 15 is interposed on the path of the lace 1 after its exit from the calender zone to ensure its correct winding.

The first support and guide means 10, the second support and guide means 12, and the third support and guide means 13 may each be in the form of a fixed shaft, a idler roller, or a motorized roller to ensure the advance of the lace 1 in the shell 20.

If several of them are motorized, they may be not perfectly synchronous, so as to ensure for example a tension of the lace 1 in the calendering zone between the second B and third C contact areas. In a variant, the second support and guiding means 12 and the third support and guiding means 13 are both motorized, and the first tends to impress the shoelace with a tangential velocity slightly greater than the second.

The optional addition of a stamping operation makes it possible to remove the calendering plate present at the end of the blade since the introduction of the calendering instead of setting the heat treatment ring. This can prevent the camber of manual springs reported.

The invention is illustrated in a particular nonlimiting example where the first support and guide means 10 is a rod, the second support and guide means 12 and the third support and guide means 13 are two rollers . In sum, at a given moment, the contact surfaces between the rod 10, the two rollers 12, 13, and the lace 1, determine on the latter a profile close to an arc with a certain instantaneous curvature.

In order for the spring 100 to be able to wind flat on the work surface, this instantaneous curvature must vary approximately regularly during all the calendering of the spiral accumulation zone 5.

And this instantaneous curvature grows, if possible on a regular basis, from the end of the blade to the neck.

For example, on the carriage 11 carrying the rod 10, a regularly increasing pressure is applied as a function of the advance of the lace 1, defined by the speed of rotation of at least one motorized roller, which may be the roller 14 of the figure 2 , or the roller 12 and / or the roller 13, this rotational speed being also adjustable.

• diamètre intérieur ou initial 2R1: 3-15mm
• diamètre extérieur ou final 2R2: 12-40mm
• pas P de la spire : 0-10 épaisseur de lame
• longueur de lame : 100-1000mm.

To quantify the calender diameters, let us quote some examples of the different quantities:

• inner or initial diameter 2R1: 3-15mm
• outer or final diameter 2R2: 12-40mm
• not P of the turn: 0-10 blade thickness
• blade length: 100-1000mm.

The calender 20 used for the implementation of this method advantageously comprises the various devices described above.

More particularly, this calender 20 comprises, on either side of a calendering zone arranged to receive a lace 1 provided beforehand with a shell 2 at one end, a first side at least a first means of support and guide 10 arranged to exert a force F on such a lace 1 in a first intermediate contact zone A, which is located between a second B and a third C extreme contact zones that respectively comprise a second 12 and a third 13 support and guiding means, which comprises the calender 20 on a second side opposite to the first side with respect to the calender zone. The exercise of this effort F on the lace 1 creates on it an accumulation zone 5 with a curvature opposite that of the shell 2.

More particularly, the first support and guide means 10 is movable relative to the second 12 and third 13 support and guiding means.

More particularly, the calender 20 comprises means for moving the first support and guiding means 10 to create such a variable force F.

More particularly, these displacement means are arranged to print to a movable carriage 11 carrying this at least one first support and guide means 10, an advance movement, or a regular advance movement, for the realization of a progressive calendering. More particularly, the displacement means are arranged to print to a mobile carriage 11 at least one pivoting movement.

More particularly, the calender 20 comprises a deflector 15 interposed on the path of the lace 1 after its exit from the calender zone to ensure its correct winding. Naturally, this deflector 15 can be motorized, and movable in one or more degrees of freedom.

More particularly still, the first support and guiding means 10 and / or the second support and guiding means 12 and / or the third support and guiding means 13 is in the form of a motorized roller to ensure the advance of the lace 1 in the calender area. More particularly, at least two of these first support and guiding means 10, second support and guiding means 12, third support and guiding means 13, are motorized in a non-synchronous manner, so as to ensure lace tension 1 in the calender zone.

More particularly, the calender 20 comprises at least one drive roller 14 motorized to ensure the advance of the lace 1 in the calender zone.

Naturally, the calender 20 may advantageously comprise driving means and / or storage means for controlling the different motorized components and reproducing identically stored sequences for obtaining springs in a reproducible manner. These control means can, again, be combined with sensors for measuring the thickness of the spring downstream of the calendering zone, and / or measuring its concavity after calendering.

The invention makes it possible to produce a clock spring 100, whose turns are not contiguous, and are distant from each other in the free state of the spring. More particularly, this spring 100 is a teflon spring, whose Teflon turns are spaced apart from each other in the free state of the spring. The invention allows the realization of such a spring.

• la suppression ou au moins la réduction de l'emmêlement des ressorts lors des manipulations, et lors des opérations en vrac telles que passage au four, lavage, téflonnage, chargement sur automates, grâce à la séparation des spires des ressorts, car le procédé de calandrage selon l'invention est étudié pour que chaque ressort reste dans une configuration plane et ne se détende pas lors des manipulations;
• la réduction des raies dues au frottement avec les galets et axes de la calandre ;
• la suppression du contact entre les spires, permettant un lavage, notamment par solvants, et un téflonnage plus efficaces ;
• la réduction du matelas du ressort résultant de l'entrecroisement des spires, fréquent dans l'art antérieur.

The progressive calendering technique according to the invention provides several advantages:

• the elimination or at least the reduction of the entanglement of the springs during the manipulations, and during the bulk operations such as passage in the oven, washing, tefloning, loading on automata, thanks to the separation of the turns of the springs, because the calendering process according to the invention is designed so that each spring remains in a planar configuration and does not relax during handling;
• reduction of the lines due to friction with the rollers and axes of the shell;
• the elimination of the contact between the turns, allowing a washing, in particular by solvents, and a more efficient tefloning;
• the reduction of the spring mat resulting from the interlacing of the turns, common in the prior art.

Claims (16)

1. Method for press-rolling a mainspring (100) from a wire (1) comprising a preformed eye (2), whereby a roller press (20) is implemented, said roller press comprising a first support and guide means (10) exerting a force (F) on said wire (1) in a first contact area (A) located between a second (B) and a third (C) contact area comprised in a second (12) and a third (13) support and guide means, in order to wind, beyond said eye (2), an accumulation area (5) with a curvature opposite to that of said eye (2), and wherein, as said wire (1) advances, the position of said first contact area (A) is gradually moved away from said second (B) and third (C) contact areas, in order to vary the press-rolling radius from a first minimum value (R1) to a second maximum value (R2) at a neck (3) junction between said accumulation area (5) and said eye (2).
2. Press-rolling method according to claim 1, characterised in that said press-rolling operation is stopped when said second maximum value (R2) is reached.
3. Method according to claim 1 or claim 2, characterised in that said third (13) support and guide means and/or said second (12) support and guide means is held in a fixed position.
4. Method according to claim 3, characterised in that said first support and guide means (10) is moved relative to said second (12) and third (13) support and guide means, which are fixed.
5. Method according to claim 1 or claim 2, characterised in that said first support and guide means (10) and/or said second (12) support and guide means is moved relative to said third (13) support and guide means, which is in a fixed position.
6. Method according to one of claims 1 to 5, characterised in that a slide (11) carrying said first support and guide means (10) is moved with at least one degree of freedom, in order to exert said force (F) on said wire (1).
7. Method according to one of claims 1 to 6, characterised in that a deflector (15) is placed in the path of said wire (1) once said wire leaves the press-rolling area to ensure the correct winding thereof.
8. Method according to one of claims 1 to 7, characterised in that one said roller press (20) is used for implementing said method, said roller press comprising, on either side of a press-rolling area arranged for receiving one said wire (1), on a first side at least said first support and guide means (10), and on a second side said second (12) and said third (13) support and guide means.
9. Method according to claim 8, characterised in that one said roller press (20) is used, said first support and guide means (10) whereof is capable of moving relative to said second (12) and third (13) support and guide means.
10. Method according to either claim 8 or claim 9, characterised in that one said roller press (20) is used, which comprises means for moving said first support and guide means (10) in order to create a said variable force (F).
11. Method according to claim 10, characterised in that one said roller press (20) is used, said moving means whereof are arranged to impart, to a movable slide (11) carrying said at least one first support and guide means (10), an advancing movement, or a regular advancing movement, in order to achieve gradual press-rolling.
12. Method according to claim 11, characterised in that one said roller press (20) is used, said moving means whereof are arranged to impart, to a movable slide (11), at least one pivoting movement.
13. Method according to one of claims 8 to 12, characterised in that one said roller press (20) is used, which roller press comprises a deflector (15) placed in the path of said wire (1) once said wire leaves said press-rolling area to ensure the correct winding thereof.
14. Method according to one of claims 8 to 13, characterised in that one said roller press (20) is used, said first support and guide means (10) whereof, and/or said second support and guide means (12) whereof, and/or said third support and guide means (13) whereof is made in the form of a motorised roll to ensure the advancing of said wire (1) inside said press-rolling area.
15. Method according to claim 14, characterised in that one said roller press (20) is used, of which at least two of said first support and guide means (10), second support and guide means (12), and third support and guide means (13), are motorised in a non-synchronous manner, to ensure a tension of said wire (1) inside said press-rolling area.
16. Method according to one of claims 8 to 15, characterised in that one said roller press (20) is used, comprising at least one motorised drive roll (14) to ensure the advancing of said wire (1) inside said press-rolling area.

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