Device for pinning and adjusting the active length of a hairspring for clock movement and method for adjusting the active length

Abstract

The invention relates to a device (1) for setting and adjusting the active length of a balance spring (2) for a watch movement, this balance spring (2) being arranged in coils of a predetermined length, this device (1) comprising a push-button (6) arranged to mechanically hold the balance spring (2) at a point along its length. The invention also relates to a method for adjusting the active length of the balance spring by means of the adjustment device (1) for setting and adjusting the active length of the balance spring.

Description

Technical field of the invention

[0001] The present invention relates to a device for pinning and adjusting the active length of a spiral spring for a watch movement. Technological background

[0002] In all that follows, by convention, a "component" will be designated as a spare part forming part of the device for pinning and adjusting the active length of a spiral spring according to the invention, and a "part" will be designated as an assembly of two or more "components".

[0003] In a mechanical timepiece, the regulating organ consists of the balance wheel and hairspring assembly in conjunction with the escapement. These various components are set in motion by the mechanical energy supplied by a mainspring and perform the counting and division of time into seconds. It is therefore clear that the accuracy of the timekeeping provided by the mechanical timepiece depends on the precision of the regulation of the balance wheel and hairspring assembly and the escapement.

[0004] One known technique for ensuring the accuracy of a balance wheel and hairspring assembly is to equip the balance wheel with a plurality of weights, for example, fixed in an adjustable manner to the rim of the balance wheel. By adjusting the position of these weights, the inertia of the balance wheel is influenced, which in turn modifies the pivoting frequency of this balance wheel and hairspring assembly.

[0005] Another known technique for ensuring the accuracy of a balance wheel and hairspring assembly involves equipping this assembly with a regulator comprising at least one regulator and a regulator key. The regulator key is mounted on the regulator and has a slot through which the hairspring passes. The regulator key can pivot on its own axis, while the regulator can pivot around the pivot axis of the balance wheel and hairspring assembly, on a bridge bearing, or around a shock-absorbing bearing.

[0006] The portion of the spiral spring extending from the racket key to the center of this spiral spring, defined by the free end of the last coil inside this spiral spring, determines the active length of the spiral spring.

[0007] The portion of the spiral spring that extends between a stud on which the free end of the last coil outside the spiral spring is fixed and the regulator key is considered to be mechanically rigid and does not participate in the oscillations of the balance wheel.

[0008] The position of the regulator key defines a point known as the counting point. This counting point can be changed by pivoting the regulator key. By changing the position of the counting point, the effective length of the balance spring is altered, and therefore the frequency of the balance wheel and hairspring assembly. By pivoting the regulator key on its axis, the movement of the hairspring is limited within the slot in the regulator key, taking care not to completely block the hairspring. This improves the precision of the adjustment of the balance wheel and hairspring assembly's oscillation frequency, and thus the accuracy of its timekeeping.

[0009] As will be clear from the above, in a number of mechanical movements for watch parts, equipping a balance wheel and hairspring assembly with means for adjusting its frequency requires a significant number of components (a stud for securing the free end of the last coil outside the hairspring, possibly a stud holder, a regulator, a regulator tail and eccentric screw for fine-tuning the regulator's position, and a regulator key). This is costly and requires a considerable amount of adjustment time to precisely set the pivoting frequency. The alternative solution of adjusting the balance wheel's inertia using regulating screws is even more expensive in terms of machining operations and the time required to adjust the pivoting frequency of the balance wheel and hairspring assembly.

[0010] Document FR 2063156 discloses a device for pinning a spiral spring. Summary of the invention

[0011] The present invention aims to overcome the aforementioned disadvantages and others by proposing a simpler and more economical device allowing both the pinning and the adjustment of the active length of a spiral spring in a watch movement.

[0012] To this end, the present invention relates to a device for the pinning and adjustment of an active length of a spiral spring for a watch movement, this spiral spring being formed of a spiral band of a determined length, this device comprising a push-button arranged to mechanically hold the spiral spring at a point along the length of the band of this spiral spring.

[0013] According to a special embodiment of the invention, the push button consists of a button and a tube in which the button is able to slide, the button being elastically returned to a rest position by an elastic element, the button being, in a service position, held away from its rest position by the interposition of a portion of the spiral spring band between the button and the tube, which ensures the mechanical retention of the spiral spring.

[0014] According to another special embodiment of the invention, the button extends between a head and a foot in which a groove is provided which goes at least partially around the foot and in which a portion of the spiral spring is engaged at the point where it is desired that this spiral spring be immobilized by pinching between the foot of the button and an end opposite the tube at two distinct points, so as to allow the push-button to transmit a holding torque to the spiral spring so that this spiral spring does not slip or rotate around its point of attachment during the life of the timepiece.

[0015] According to yet another special embodiment of the invention, the groove extends over an entire outer perimeter of the button.

[0016] According to another special embodiment of the invention, the elastic element is a spring.

[0017] According to yet another special embodiment of the invention, the spring is an elastic blade.

[0018] According to yet another special embodiment of the invention, the button is provided with a groove in which is engaged the portion of the spiral spring band whose presence ensures that the button is held in the service position.

[0019] According to yet another special embodiment of the invention, the groove extends over an entire outer perimeter of the button.

[0020] According to yet another special embodiment of the invention, the push-button is fixed to a bridge of the watch movement.

[0021] According to yet another special embodiment of the invention, the device for the pinning and adjustment of the active length of the spiral spring comprises a push-bearing component which carries the push-button, this push-bearing component being arranged to be able to pivot around a pivot axis of a balance wheel-spiral assembly of the watch movement.

[0022] According to yet another special embodiment of the invention, the push-button holder is pivotally mounted on a support.

[0023] According to yet another special embodiment of the invention, the support is a balancing bridge or a bearing carried by this bridge.

[0024] According to yet another special embodiment of the invention, the bearing is a shock-absorbing bearing.

[0025] According to yet another special embodiment of the invention, a scale comprising a plurality of graduations, each corresponding to a fraction of a time of an advance or a delay of the clock movement, is placed on a bridge of a plate of the clock movement or on the plate.

[0026] The invention also relates to a method of adjusting the active length of a spiral spring of a watch movement by means of the device according to the invention, in which, to adjust the active length of the spiral spring, the spiral spring is momentarily released by pressing the push-button, then a balance wheel whose beats are ensured by the spiral spring is rotated by a desired angle, then the pressure on the push-button is released to immobilize the spiral spring again, the rotation of the balance wheel causing the displacement of a marker which is then realigned by rotating the device.

[0027] Thanks to these features, the present invention provides a device that allows both the screw-in and the adjustment of the active length of a balance spring in a watch movement, thereby precisely regulating the rotation frequency of the balance wheel and hairspring. Since the balance spring is screwed in without the use of adhesive, it can be repositioned at any time, allowing the rotation frequency of the balance wheel and hairspring to be adjusted during the watch's lifetime, for example, when it is returned to the factory. Furthermore, because there are no constraints related to the choice of adhesive, the watchmaker has complete freedom in selecting the material from which the balance spring is made.

[0028] In its simplified embodiment, the device according to the invention thus advantageously allows the functions of stud and racket to be combined, which makes it possible to reduce the number of components required and to simplify the integration of the device according to the invention into a watch movement due to a reduced size.

[0029] Furthermore, in a preferred embodiment of the invention, the device includes a push-holder piece by means of which the pinning and adjustment device can be mounted pivoting around a pivot axis of a balance wheel-spring assembly, which allows the balance wheel marker to be adjusted.

[0030] Thus, in a truly remarkable way, the present invention provides a device which, by means of a single part, allows up to four distinct functions for a spiral spring of a watch movement which seem a priori incompatible with each other, namely: repositionable stud, mounting of the stud holder on its support, adjustment of the active length and adjustment of the marker.

[0031] It should also be noted that, in the prior art, the balance spring is conventionally attached by a stud, while the counting point is adjusted using a regulator key. In contrast, according to the invention, the device allows both the balance spring attachment point and the counting point to be combined at a single point. One of the advantages of this device is that, in a simplified embodiment of the invention, it allows the use of a balance wheel from the balance-spring assembly that lacks its own means of adjusting its inertia, thus resulting in substantial cost savings. Brief description of the figures

[0032] Other special embodiments and advantages of the present invention will become clearer from the following detailed description of an embodiment of a device for pinning and adjusting the active length of a spiral spring according to the invention, this example being given purely by way of illustration and not limitation, in conjunction with the attached drawing in which: there figure 1 is a top view of the device for pinning and adjusting the active length of a balance spring for a watch movement according to the invention; the figure 2 is a cross-sectional view along the section line II-II of the figure 1 ; there figure 3 is a perspective view of a particular embodiment of the terminal curve of a spiral spring specifically adapted to cooperate with the device according to the invention; the figure 4is a perspective view from below showing the arrangement between the push button of the device according to the invention and the spiral spring of the figure 3 ; there figure 5 is a schematic representation of the device according to the invention fixed to a bridge of the watch movement by means of a screw. Detailed description of the invention

[0033] The present invention stems from the general inventive idea of ​​combining in a single component at least some of the functions of a balance spring designed to ensure the isochronous oscillations of a balance wheel in a balance-spring assembly of a watch movement. To this end, the present invention provides a device comprising, firstly, a push-button arranged to immobilize a balance spring of a watch movement at a specific point along its length without the need for adhesive. Consequently, the watchmaker has complete freedom in choosing the material from which the balance spring is made, and furthermore, since the balance spring is not glued, the device according to the invention can be disassembled at any time, for example, when the timepiece is returned to the factory.Therefore, the device according to the invention initially allows for the repositionable pinning of the balance spring. Furthermore, by means of a push-button, the balance spring can be immobilized at any point along its length, thus enabling the adjustment of its active length—that is, the distance between the point where the balance spring is immobilized by the push-button and the free end of the first coil inside the balance spring. The device according to the invention therefore also allows for the adjustment of the pivoting frequency of the balance wheel and balance spring assembly equipped with the device. Finally, in its preferred embodiment, the device according to the invention is equipped with a push-holder that allows for its fixed mounting, for example, on a bridge of the watch movement, or its pivoting mounting on a support such as a balance bridge or a bearing carried by this bridge.In this embodiment, the device according to the invention thus performs four distinct functions: the repositionable pinning of the balance spring, the mounting of the pin holder on its support, the adjustment of the active length of this same balance spring, and the adjustment of the balance wheel's marker. The device according to the invention, consisting of a single piece formed, in a simplified embodiment, of a tube, a button, and an elastic element, therefore advantageously replaces the assembly of prior art components such as a pin, pin holder, regulator, regulator key, regulator tail, and eccentric, thereby reducing the number of components required for securing the balance spring and adjusting the pivot frequency of the balance wheel-spring assembly, and facilitating the mounting of the device according to the invention in the watch movement due to its reduced size.Another key advantage of the invention is that it eliminates the need for glue.

[0034] Designated as a whole by the general numerical reference 1, the device according to the invention is shown in top view at the figure 1 , and in cross-section along line II-II of the figure 1 to the figure 2 .

[0035] In a simplified embodiment, the device 1 according to the invention allows the pinning of a spiral spring 2 for a watch movement, as well as the adjustment of an active length of this spiral spring 2.

[0036] The spiral spring 2, arranged in coils, has a determined length between a free end of a first coil inside and a free end of a last coil outside 3. By way of example only, the spiral spring 2 can be formed into a flat strip delimited by first and second faces which extend parallel to and at a distance from each other.

[0037] More specifically, the device 1 according to the invention makes it possible to immobilize, advantageously in a demountable manner as described below, the spiral spring 2 at any point along its length, and to adjust the length which separates a point 4 where this spiral spring 2 is immobilized from the free end of the first coil inside this same spiral spring 2.

[0038] For this purpose, the device 1 according to the invention includes firstly a push-button 6 arranged to hold the spiral spring 2 in a releasable manner at a point along the length of the band of this spiral spring 2.

[0039] As seen on the figure 2 The push button 6 essentially comprises a button 8 and a tube 10 in which the button 8 is able to slide. Advantageously, the button 8 is elastically returned to a rest position by an elastic element 12 of the type of a spring or an elastic blade (see, in particular, the figure 1 ).

[0040] The button 8 is, in a service position, kept away from its rest position by interposition of a portion of the spiral spring 2 between the button 8 and the tube 10, which ensures the mechanical immobilization of the spiral spring 2.

[0041] According to one of the essential advantages of the invention, it is readily understood that the spiral spring 2 can be released from its grip on the push button 6 at any time. To do this, it is sufficient to apply pressure to the button 8 that opposes the restoring force of the elastic element 12 in order to move it further out of the tube 10. On the other hand, it is understood that by appropriately choosing the stiffness coefficient of the elastic element 12, the pinching force exerted on the spiral spring 2 when it is held stationary between the button 8 and the tube 10 of the push button 6 can be precisely controlled. Consequently, the risks of breaking the spiral spring 2, particularly when it is made of silicon, are limited.

[0042] We can see on the figure 2that the button 8 extends between a head 14 and a foot 16 in which a groove 18 is provided which goes at least partially around the foot 16. Consequently, the spiral spring 2 is passed around the foot 16 of the button 8 in the portion where it is desired to be immobilized by the push-button 6 by pinching between the foot 16 of the button 8 and the opposite end of the tube 10. The spiral spring 2 is thus pinched between the foot 16 of the button 8 and the opposite end of the tube 10 at two points, which allows the push-button 6 to transmit a holding torque to the spiral spring 2 so that this spiral spring 2 does not slip or rotate around its fixing point during the life of the timepiece.

[0043] According to a simplified embodiment of the invention illustrated in the figure 5 , the device 1 according to the invention and its push button 6 are simply fixed on a bridge 20 of a plate of the watch movement, typically by means of a screw 21.

[0044] According to an improved embodiment of the invention, the device 1 for pinning and adjusting the active length of the balance spring 2 further comprises a push-holder 22 which carries the push-button 6, as well as a balance wheel 24 forming part of a balance wheel-spring assembly 26. The push-holder 22 is arranged to be able to pivot about a pivot axis. D of the balance wheel-spring assembly 26 of the watch movement.

[0045] For this purpose, the push-button holder 22 is provided with an opening 28 whose inner diameter is adjusted to the outer diameter of the pivot axis. D of the balance wheel-spring assembly 26. The device 1 according to the invention thus advantageously fulfills both the function of stud and stud holder.

[0046] As depicted on the Figures 1 And 2, the balance wheel-spiral assembly 26 is preferentially pivoted in a shock-absorbing bearing 30 classically comprising a chaton 32, a jewel with a hole 34, a counter-pivot jewel 36 and a spring 38.

[0047] It is understood that the present invention is not limited to the embodiment just described, and that various simple modifications and variations can be envisaged by those skilled in the art without departing from the scope of the invention as defined by the appended claims. In particular, it should be noted that to facilitate the adjustment of the active length of the spiral spring 2, at least a portion of the spiral band forming this spiral spring 2 may be provided with a scale 40, each graduation of which represents, for example, a variation of 0.1 s, as can be seen in the figures 3 and 4To adjust the active length of the balance spring 2, simply press button 8 on the push-button 6 to momentarily release the balance spring 2, then rotate the balance wheel 24 by the desired angle to correct a known gain or loss. For example, if the watch movement gains 1 second per day, the balance wheel-spring assembly 26 is moved to induce a loss by passing 10 graduations of 0.1 seconds in front of an index 42. Then, release the pressure on button 8 of the push-button 6 to immobilize the balance spring 2 again. Rotating the balance wheel 24 will also cause the marker to move, which can then be realigned by rotating the device 1, which consists of the push-button 6 and the push-holder 22 carrying the push-button 6. It will be understood, of course, that this operation is not possible in the case of the simplified embodiment of the invention illustrated in the figure. figure 5It should also be noted that, for the purposes of this invention, a push button is defined as an assembly consisting of a cylinder and a tube, inside which the cylinder is able to slide against the elastic restoring force of a spring. It should also be noted that, as already mentioned above, the spiral spring 2 is immobilized at two points, one located on the terminal curve and the other in the region where the scale can be provided. Nomenclature

[0048] 1. Device 2. Spiral spring 3. Last outer coil 4. Point 6. Push button 8. Button 10. Tube 12. Elastic element 14. Head 16. Foot 18. Throat 21. Screw 22. Push button holder 24. Rocker arm D 26. Pivot axis 28. Balance wheel and hairspring assembly 30. Opening 32. Shock-absorbing bearing 34. Jewel 36. Jewel with hole 38. Counter-pivot jewel 40. Spring 42. Scale 43. Index

Claims

1. Device (1) for pinning up to the stud and setting an active length of a balance-spring (2) for a horological movement, this balance-spring (2) being arranged in coils along a determined length, this device (1) being characterised in that it comprises a push-button (6) arranged to hold the balance-spring (2) mechanically at a location of the length of this balance-spring (2).

2. Device (1)according to claim 1, characterised in that the push-button (6) is composed of a button (8) and a tube (10) wherein the button (8) is capable of sliding, the button (8) being returned elastically to a locking position by an elastic organ (12), the button (8) being, in an operating position, kept separate from the locking position thereof by the insertion of a portion of the balance-spring (2) between the button (8) and the tube (10), which ensures the mechanical hold of the balance-spring (2).

3. Device (1) according to claim 2, characterised in that the button (8) extends between a head (14) and a foot (16) wherein a groove (18) is arranged which goes at least partially around the foot (16) and wherein is engaged a portion of the balance-spring (2) at the location where it is sought to stop the balance-spring (2) by gripping between the foot (16) of the button (8) and an end facing the tube (10) along two distinct points, so as to enable the push-button (6) to transmit a holding torque to the balance-spring (2) so that this balance-spring (2) does not slide or does not turn about its fastening point over the lifetime of the timepiece.

4. Device (1) according to claim 3, characterised in that the groove (18) extends along an entire outer perimeter of the button (8).

5. Device (1) according to one of claims 2 to 4, characterised in that the elastic organ (12) is a spring.

6. Device (1) according to claim 5, characterised in that the spring is an elastic strip.

7. Device (1) according to one of claims 1 to 6, characterised in that the button (8) is provided with a groove (18) wherein is engaged the portion of the balance-spring (2) the presence of which holds the button (8) in the operating position.

8. Device (1) according to one of claims 1 to 7, characterised in that the push-button (6) is arranged to be fastened to a balance bridge (20) of the horological movement.

9. Device (1) according to one of claims 1 to 7, characterised in that the device (1) for pinning up to the stud and setting the active length of the balance-spring (2) comprises a push-piece support (22) which bears the push-button (6), this push-piece support (22) being arranged to be capable of pivoting about a pivoting axis (D) of a spring balance assembly (26) of the horological movement.

10. Device (1) according to claim 8, characterised in that the push-piece support (22) is mounted pivoting on a support.

11. Device (1) according to claim 10, characterised in that the support is a balance bridge (20) or a bearing borne by this bridge.

12. Device (1) according to claim 11, characterised in that the bearing is a shock-absorbing bearing (30).

13. Device (1) according to one of claims 1 to 12, characterised in that a scale (40) comprising a plurality of graduations, each of which corresponds to a gain or loss time fraction of the horological movement is mounted on a bridge (20) of a plate of the horological movement or on the plate.

14. Process for setting the active length of a balance-spring (2) of a horological movement by means of a device (1) according to one of claims 1 to 12, characterised in that, to adjust the active length of the balance-spring (2), the balance-spring (2) is momentarily released by pressing on the push-button (6), then a balance (24) the beats of which are provided by the balance-spring (2) is pivoted by a desired angle, then the pressure is released on the push-button (6) to once again stop the balance-spring (2), the pivoting of the balance (24) triggering the movement of a guide-mark which is subsequently realigned by turning the device (1).

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