TWI410761B - Balance spring-collet assembly for a timepiece movement - Google Patents

Abstract

A balance spring-collet assembly for a timepiece movement comprises a collet (1) and a balance spring (3) attached at its inner end to the collet (1). The collet (1) is capable of being mounted onto a shaft (2). The external periphery of the collet (1) defines abutments (10a, 10b, 10c) against which the inner turn of the balance spring (3) may come to rest during a shock before the elastic limit of the inner turn is exceeded. The abutments (10a, 10b, 10c) are situated at respective distances (Ra, Rb, Rc)from the center (O) of the shaft (2) that increase in the direction (D) of the balance spring (3) from the inside to the outside starting at the point (8) of junction between the balance spring (3) and the collet (1).

Description

Hairspring inner pile assembly

The present invention relates to a hairspring inner pile assembly for a timepiece, and more precisely to a hairspring, the inner end of which is attached to a pile, which can be driven to a shaft of a balance spring, In order to form the adjustment device of the movement.

It is known that when the watch is subjected to a steep shock, the balance spring of the adjusting device can be deformed beyond its elastic limit, and thus can be subjected to a permanent deformation which is harmful to its operation, or if its constituent material is a fragile material such as enamel, It can even break.

Patent CH 500 523 describes a pile containing three seats at its periphery. In the event of a radial steep shock, the inner wire of the balance spring can come to the support to limit the deformation of the balance spring. These three pedestals are equidistant from the center of the hairspring shaft. Therefore, one of these supports must be closer to the internal turns than the other two seats. In the sense that the closest abutment can be contacted by the inner wire during normal operation of the movement, this configuration can be a problem that can disrupt the operation, particularly if the amplitude of the vibration of the balance spring is Large, and/or in the event of a steep shock, the farthest support may be too far away, and the inner wire may not be used as a docking surface until the elastic limit of the seat is exceeded.

The present invention is directed to remediating the aforementioned shortcomings of the prior art, and for this purpose, a hairspring inner pile assembly is provided according to item 1 of the appended patent application, that is, a hairspring inner pile assembly includes a inner pile and one inner side thereof An end portion is attached to the balance spring of the inner pile, the inner pile is designed to be mounted on a shaft, the outer periphery of the inner pile defining the support, and the inner turns of the spring can be exceeded during a steep earthquake The elastic limit of the inner turn comes before the stop to the support, characterized in that the support is at an individual distance from the center of the shaft, the distance between the balance between the balance spring and the inner pile Initially, the inner side to the outer side are increased in the direction of the hairspring.

A particular embodiment of the hairspring pile assembly is defined in the dependent claims 2 to 13 of the accompanying claims.

The present invention also proposes a timepiece movement including the hairspring inner pile assembly.

Referring to Figures 1 and 2, a hairspring inner pile assembly for a timepiece according to a first embodiment of the present invention comprises a pile 1, which is intended to be mounted on a balance spring shaft 2; and a balance spring 3, and Attached to the inner pile 1 at its inner end. In this figure, the balance spring 3 is partially shown and only its internal turns are visible.

The inner pile 1 comprises three elastic arms 4 arranged in a triangular shape. The resilient arms 4 define a central equilateral triangular opening 5 having a diameter that is slightly smaller than the diameter of a cylindrical or slightly conical contact surface 6 of the shaft 2 such that the shaft 2 can be driven into the inner pile 1, which drives the arm 4 to elastically deform outwardly. Due to the shape of its triangle, the periphery of the opening 5 defines three discrete points 7 that are in contact with the shaft 2. The width L of each arm 4 is variable in the manner of the elastic arms of the pile in the European Patent Document EP 1,637,940, in order to generate a stress applied in a given arm 4 by the shaft 2. Evenly distributed.

The joint 8 between the balance spring 3 and the inner pile 1 is defined by a region 9c of one of the three regions 9a, 9b, 9c joined by the arms 4. Since the inner pile 1 is driven to the shaft 2, the inner end of the balance spring 3 is firmly connected to the shaft 2, and thus the oscillating movement of the balance spring is followed. The outer end portion (not shown) of the balance spring 3 is fixed to a fixed portion of the movement, typically the stopcock, by stud bolts in a conventional manner.

The inner pile 1 is preferably a one-piece structure having a balance spring 3. The hairspring pile assemblies 1, 3 are typically made of a fragile material, that is, a material that cannot be plastically deformed, such as a material based on enamel, glass, quartz, or diamond. In an exceptional case, a suitable process for the hairspring pile assemblies 1, 3 is the DRIE (Deep Reactive Ion Etching) process. However, in a variant, the balance spring pile assemblies 1, 3 may be made of an extensible material, such as a metallic material.

According to the invention, the discrete segments 10a, 10b, and 10c of the outer periphery of the inner pile 1 constitute a support, and the inner turns of the balance spring 3 can be stopped by the abutment during the steep shock period. These supports 10a, 10b, and 10c are defined by the regions 9a, 9b, and 9c where the resilient arms 4 are joined, and are thus disposed in a substantially regular angular distribution. In the plane of the inner pile 1, the supports 10a, 10b, and 10c are respectively at a distance Ra, Rb, and Rc from the center O of the shaft 2, and more precisely have a circular arc shape, and Center O and radius Ra, Rb, and Rc are respectively provided. The equidistances or radii Ra, Rb, and Rc are selected to be sufficiently small that the balance spring 3 is not disturbed by the supports 10a, 10b, and 10c during normal vibration of the balance spring, but is sufficiently large that During the steep shock experienced by the movement, the internal thread of the balance spring 3 can exceed any point of the line of the joint 8 until the end of the elastic limit of the inner thread, to the docking of one or several The supports 10a, 10b, and 10c (Fig. 2). When the inner wire is docked against one or more of the supports 10a, 10b, and 10c under the effect of a steep shock, any of the other turns may come to the turn before it. In this way, the hairspring 3 can be damaged by the breakage when it is made of a fragile material, or the risk of permanent deformation when it is made of a ductile material.

Advantageously, starting at the joint 8 between the balance spring 3 and the inner pile 1, the equidistances or radii Ra, Rb, and Rc are increased from the inner side to the outer side in the direction D of winding of the balance spring 3, in order to take this into account. The fact that, like the radius of all other turns, the radius of the inner turn of the balance spring 3 increases in this direction D. Thus, the holder 10a closest to the joint 8 in the direction D is separated by a distance Ra from the center O, which is smaller than the distance Rb between the lower seat 10b and the center O, and the distance Rb is The sequence ratio is smaller than the distance Rc between the lower seat 10c and the center O. The distance R8 from the joint 8 between the balance spring 3 and the inner pile 1 to the center O is typically greater than the distance Ra or the distance Ra, but less than the distances Rb and Rc.

These distances Ra, Rb, and Rc are calculated by the radial force F defining a certain number of guiding centers O, by calculation, by, for example, the finite element method, the internal wire 匝 under the action of each radial force F The maximum elastic deformation that can be suffered, and by selecting a sufficiently large distance Ra, Rb, and Rc such that the maximum elastic deformation cannot be obtained or at least not exceeded, but small enough that the balance spring 3 does not contact the support 10a during its normal operation. , 10b, and 10c are determined.

At this point, respectively, the configuration of the corresponding support 10a, 10b or 10c is placed, and each of the supports 10a, 10b, and 10c is respectively faced by the radial force F applied at this point. The points 3a, 3b, and 3c, such that the deformation of the inner turns of the balance spring 3 is less than or equal to a percentage of 100% of the maximum elastic deformation, the maximum elastic deformation being the point at which the inner wire can be suffered. This gives a safety factor of more than one or one (the maximum elastic deformation and the ratio between the elastic deformations when the inner wire is resting on a seat 10a, 10b or 10c). The percentages are preferably substantially the same for all of the supports 10a, 10b, 10c. In an exemplary implementation of the invention, the percentage is about 50 percent (about two safety factors) and is used for a hairspring of about 93 microns during normal operation of the hairspring relative to the maximum elastic deformation of the inner turns. The pitch of 3 and the thickness or width of the turns of the hairspring 3 of about 30 microns, the percentage of deformation of the inner turns is about 25 percent.

In a simplified variant based on a linear approximation of the deformation of the inner turn, as a function of the position on the turn, the distances Ra, Rb, and Rc are respectively the corresponding radii of the inner turn at the stop. Ra, rb, and rc, that is, the same percentage of the distance between points 3a, 3b, 3c and the center O. For the pitch of the hairspring 3 of about 93 microns and the thickness or width of the turns of the balance spring 3 of about 30 microns, the percentage is, for example, about 90 percent.

As such, it can be seen that due to the fact that the distances Ra, Rb and Rc increase from the joint 8 in the direction D, the safety factors for the supports 10a, 10b and 10c may be identical or may be at least close to each other. If a radial steep shock occurs, the inner pile 1 will thus be able to protect the balance spring 3 in a reliable manner, regardless of the direction of the steep shock, without disturbing the normal operation of the adjusting device formed by the hairspring, even if the hairspring vibrates The amplitude is large.

Figure 3 shows a further embodiment of the invention, in addition to the support 10a, 10b, 10c defined by the joint regions 9a, 9b, 9c between the arms 4, the stud 1 comprises by means of the element 11 The abutments 10d, 10e, 10f are defined by the outer sides of the arms 4 projecting radially in the central region of the arms 2 contacting the shaft 2. Like the holders 10a, 10b, 10c, the holders 10d, 10e, 10f have a central arc shape at the center O of the shaft 2. At the joint 8 between the balance spring 8 and the inner pile 1, the individual distances Ra to Rf between the supports 10a to 10f and the center O increase from the inner side to the outer side in the direction D of the balance spring, in other words, Rd<Ra <Re<Rb<Rf<Rc.

The invention is in no way limited to the specific embodiments described above. In fact, it is obvious that modifications can be made without departing from the scope of the invention. For example, the opening 5 of the stud 1 into which the shaft 2 is driven may have a shape that is different from a triangle, such as another regular or irregular polygonal shape defined by more than three elastic arms. In another variation, the stud can take the form of a split ring and have a radially projecting portion defining the seats. In yet another variation, the supports may be continuous rather than discrete, and more particularly, a large continuous segment of the outer periphery of the inner pile can be used as the support. The outer periphery will then have a shape similar to the inner turn, i.e., the point at which the joint between the balance spring and the inner pile begins to increase from the inner side to the outer side in the winding direction D of the balance spring. In this case, the outer perimeter may be defined by a frame that surrounds the resilient arms, or it may be the outer perimeter of a complete inner pile without an elastic cut.

1. . . Pile

2. . . Hairspring shaft

3. . . gossamer

3a. . . point

3b. . . point

3c. . . point

4. . . Elastic arm

5. . . Opening

6. . . Contact surface

7. . . discrete point

8. . . Joint

9a. . . region

9b. . . region

9c. . . region

10a. . . Support

10b. . . Support

10c. . . Support

10d. . . Support

10e. . . Support

10f. . . Support

Further features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which: FIG. 1 shows the hairspring inner pile assembly in its resting position in accordance with the present invention; 2 shows that the balance spring pile assembly of Figure 1 is in a steep shock period; Figure 3 shows the balance spring pile assembly in its rest position in accordance with another embodiment of the present invention.

1. . . Pile

2. . . Hairspring shaft

3. . . gossamer

3a. . . point

3b. . . point

3c. . . point

4. . . Elastic arm

5. . . Opening

6. . . Contact surface

7. . . discrete point

8. . . Joint

9a. . . region

9b. . . region

9c. . . region

10a. . . Support

10b. . . Support

10c. . . Support

Claims (14)

A hairspring inner pile assembly for a timepiece, comprising a inner pile (1) and a balance spring (3) attached to the inner pile (1) at an inner end thereof, the inner pile (1) is designed Suitable for mounting on a shaft (2), the outer periphery of the inner pile (1) defining a support (10a, 10b, 10c), the inner turns of the hairspring (3) being elastic beyond the inner turn The abutment period before the limit comes to the docking station, characterized in that the seats (10a, 10b, 10c) are anchored at an individual distance from the center (O) of the shaft (2) (Ra , Rb, Rc), the distance begins at a joint (8) between the balance spring (3) and the inner pile (1), and increases from the inner side to the outer side in the direction (D) of the balance spring (3) . The balance spring pile assembly of claim 1, wherein the support (10a, 10b, 10c) is sufficiently far away from the balance spring (3) so that the balance spring is not protected by the balance spring during normal operation (3) ) contacted. A hairspring pile assembly according to claim 1, wherein the supports (10a, 10b, 10c) are formed by discrete segments of the outer periphery of the inner pile (1). The balance spring pile assembly of claim 3, wherein the number of the supports (10a, 10b, 10c) is at least three. The balance spring pile assembly of claim 3, wherein the supports (10a, 10b, 10c) are distributed according to a substantially regular angular distribution. Configuration. The balance spring pile assembly of claim 3, wherein the supports (10a, 10b, 10c) are substantially circular arc shaped, and the center (O) of the shaft (2) is regarded as the center thereof . A hairspring pile assembly according to claim 3, wherein the inner pile (1) comprises an elastic arm (4) configured as a polygon, the shaft (2) being driven into between the arms And at least one of the supports (10a, 10b, 10c) is in the joint zone (9a, 9b, 9c) between the arms of the elastic arms (4). A hairspring pile assembly according to claim 3, wherein the inner pile (1) comprises an elastic arm (4) configured as a polygon, the shaft (2) being driven into between the arms And at least one of the supports (10d, 10e, 10f) is defined by an element (11) projecting from the outer side of one arm of the elastic arms (4). For example, in the hairspring pile assembly of claim 1, wherein each distance of the distances (Ra, Rb, Rc) is selected in a group configuration, in the configuration, A point (3a, 3b, 3c) of the inner turns of the balance spring (3) is being stopped by the corresponding support (10a, 10b, 10c) under the action of a radial force (F), the radial force being directed to the The center (O) of the shaft (2) is applied to the point (3a, 3b, 3c), and the deformation of the inner wire of the hairspring (3) at this point (3a, 3b, 3c) will be the internal thread A certain percentage of the maximum elastic deformation that can be experienced at this point (3a, 3b, 3c), for all such distances (Ra, Rb, Rc), the percentages are substantially the same. For example, the hairspring pile assembly of claim 1 of the patent scope, wherein At rest, the inner wire faces a point (3a, 3b, 3c) of the corresponding support (10a, 10b, 10c), and each distance of the equidistances (Ra, Rb, Rc) is the balance spring (3) A percentage of the radius of the internal turns (ra, rb, rc), which is substantially the same for all such distances (Ra, Rb, Rc). For example, the hairspring pile assembly of the first application of the patent scope, wherein the hairspring pile assembly is a one-piece structure. The balance spring pile assembly of any one of claims 1 to 11, wherein the balance spring pile assembly is made of a material that is not plastically deformable. For example, the hairspring pile assembly of claim 12, wherein the hairspring pile assembly is made of a material based on enamel. A timepiece movement comprising a balance spring pile assembly according to any one of claims 1 to 13.