Separating device for separating components of hairspring and hairspring manufacturing method

Abstract

One aspect of the invention relates to a separation device (100) for separating an assembly (10) of a hairspring (12), the hairspring (12) having been wound and undergoing an expansion cycle, the separation device (100) comprising: a support (110) comprising a recess (113) for receiving an inside harness (13) of the wound hairspring (12) constituting the assembly (10); a vibration table (120) movable along two different axes extending in the same plane defining a vibration plane (P1), the vibration table (120) being configured to vibrate the support (110) in a plane parallel to the vibration plane (P1). Another aspect of the invention relates to a method for producing a hairspring.

Description

Field of the Invention

[0001] The present invention relates to a method for manufacturing a hairspring intended to equip the balance wheel of a watch movement, and a method for manufacturing such a hairspring.

[0002] The present invention relates to a separating device for separating individual hairsprings to facilitate the step of separating the individual hairsprings after heat treatment in the hairspring manufacturing method.

[0003] The present invention also relates to a method for manufacturing a hairspring intended to equip the balance wheel of a watch movement. Background Art

[0004] The manufacture of watch hairsprings is subject to a number of limitations that often appear difficult to reconcile at first glance:

[0005] - The need to obtain a high yield strength;

[0006] - Easy to manufacture, particularly the drawing and rolling operations;

[0007] - Excellent fatigue strength;

[0008] - Maintaining a stable performance level over time;

[0009] - Small cross-section.

[0010] In addition, the production of hairsprings also focuses on thermal compensation to ensure a consistent level of timekeeping performance. This requires obtaining a thermal elastic coefficient close to zero. Hairsprings with limited magnetic field sensitivity are also sought.

[0011] Any improvement in at least one of the above, particularly in terms of limited magnetic field sensitivity, thermal compensation, and ease of manufacture (particularly stretching, drawing, and rolling operations), represents a significant advance.

[0012] In the manufacturing cycle of a hairspring, the winding operation involves winding a plurality of rolled wires around a barrel by means of a winding star or a spindle, thereby forming an assembly or a plate composed of a plurality of hairsprings wound in the same plane.

[0013] This assembly typically includes 3 to 6 helically wound wires.

[0014] Then, each of the wound hairsprings is fixed by means of an expansion cycle (usually heat treatment) to give these hairsprings a final Archimedean spiral shape with a regular pitch in order to obtain the desired thermal elastic coefficient (TEC) and increase hardness. The next step involves separating the individual interlocked wound hairsprings.

[0015] For compensating hairsprings, this step is particularly difficult, and even more so for titanium alloy hairsprings, because the titanium present in the alloy increases the friction between the individual hairsprings.

[0016] Therefore, it is necessary to improve this hairspring separation step after winding and heat treatment, in order to, in particular, minimize the scrap rate during the manufacturing process of such hairsprings, especially compensating hairsprings. Summary of the Invention

[0017] In this context, the present invention proposes a separation device for a component for separating hairsprings, the hairsprings having been wound and subjected to an expansion cycle, the separation device comprising:

[0018] - a support member including a notch for receiving the inner strands of the wound hairsprings forming the component;

[0019] - a vibrating table capable of moving along two different axes extending in the same plane and defining a vibration plane P1, the vibrating table being configured to vibrate the support member in a plane parallel to the vibration plane P1.

[0020] Such a separation device helps to separate components of multiple wound hairsprings after heat treatment. Such a separation device is particularly effective for compensating hairsprings, especially those made of titanium alloy.

[0021] Preferably, the two vibration axes are orthogonal to each other.

[0022] By vibrating in two directions in the same plane, in particular, a vibrating motion tangential to the coils of the hairspring can be generated.

[0023] Such vibration elastically deforms the individual coils of the hairspring by matching the shape of the coils, starting from the center of the component and propagating towards the outermost coils of the hairspring.

[0024] In addition to the features mentioned in the previous paragraphs, the separation device according to the present invention may also have one or more of the following additional features, which may be considered individually or in any technically feasible combination:

[0025] - the vibrating table vibrates in a circular translational motion;

[0026] - the support member includes a body integral with the vibrating table and a main shaft integral with the body, the main shaft extending perpendicular to the body and the vibration plane P1 of the vibrating table;

[0027] - the notch is formed at the free end of the main shaft;

[0028] - the free end of the main shaft is conical;

[0029] - the separation device includes an air ejector for ejecting the separated hairsprings when the vibrating table vibrates;

[0030] - The separating device includes a collecting tray for receiving the ejected hairspring.

[0031] - The separating device includes a removable cover configured to at least partially cover the free end of the spindle.

[0032] - The removable cover is movable between a closed position that prevents the hairspring from being removed from the support and an open position that allows the assembly for winding the hairspring to be inserted onto the support and allows the separated hairspring to be removed from the support.

[0033] - The removable cover is capable of translating along an axis perpendicular to the vibration plane P1 of the vibrating table.

[0034] - The removable cover includes a groove configured to receive the free end of the spindle when the removable cover is in the closed position.

[0035] - The separating device includes a motor configured to vibrate the vibrating table at a frequency between 1,000 Hz and 12,000 Hz, preferably at a frequency between 4,000 Hz and 8,000 Hz.

[0036] - The motor is a pneumatic motor or a piezoelectric motor.

[0037] Another aspect of the present invention relates to a manufacturing method for manufacturing a hairspring intended to equip the balance wheel of a watch movement.

[0038] According to the present invention, the manufacturing method particularly includes a separating step of separating a hairspring assembly, the hairspring having been wound and subjected to an expansion cycle, and this separating step is carried out by operating the separating device according to the present invention.

[0039] Preferably, the manufacturing method includes a winding step before the separating step, and the winding step includes winding a plurality of rolled wires in a barrel by means of a winding star to form an assembly for winding the hairspring.

[0040] Preferably, the manufacturing method includes an expansion step after the winding step to release the stress in the assembly for winding the hairspring.

[0041] Preferably, the hairspring is a compensating spring.

[0042] Preferably, the hairspring is made of a niobium-titanium alloy. Description of the Drawings

[0043] The objects, advantages, and features of the present invention will be better understood by reading the following detailed description with reference to the accompanying drawings:

[0044] - Figure 1Schematically shows an exemplary embodiment of a separating device for separating a hairspring that has undergone an expansion cycle according to the present invention;

[0045] - Figure 2 Schematically shows during the step of closing and vibrating the assembly of the hairspring, Figure 1 the separating device according to the present invention as shown;

[0046] - Figure 3 Schematically shows during the step of ejecting the separated hairspring after vibration, Figure 1 the separating device according to the present invention as shown;

[0047] - Figure 4 Shows Figure 1 a top view of the vibrating table and the support of the separating device as shown;

[0048] - Figure 5 Shows a block diagram of the main steps of a manufacturing method for manufacturing a hairspring intended to equip a balance wheel of a watch movement according to the present invention;

[0049] - Figure 6 Schematically shows a barrel containing an assembly of multiple wound hairsprings, the multiple wound hairsprings being fixed by means of an expansion cycle;

[0050] - Figure 7 Schematically shows a hairspring in its final state, the hairspring being intended to equip a balance wheel of a watch movement. Detailed Description

[0051] During the manufacturing cycle of the hairspring, the winding operation includes winding multiple rolled wire filaments in a barrel 2 (shown in Figure 6 ) by means of a star-shaped part or a winding spindle, thereby forming an assembly or plate composed of multiple wound filaments, the filaments being in the same plane and wound in the same plane. From this step on, the wound filaments are regarded as wound hairsprings because their shape is determined and determined by the barrel 2.

[0052] Then, each wound hairspring forming the assembly 10 is fixed by means of an expansion cycle (usually a heat treatment) so that they finally form an Archimedean spiral shape with a regular pitch.

[0053] Figure 6 Schematically shows an assembly 10 of multiple wound hairsprings 12 fixed by means of an expansion cycle.

[0054] Figure 7 Schematically shows a hairspring 12 in its final state, the hairspring being used to equip a balance wheel of a watch movement.

[0055] Typically, the assembly 10 consists of 3 to 6 hairsprings 12. In the example shown, the assembly 10 includes 4 hairsprings 12.

[0056] The next step involves separating the individual wound and heat-fixed hairsprings 12 in the assembly 10.

[0057] Figure 1 An exemplary embodiment of a device 100 for separating the assembly 10, which consists of a plurality of wound and heat-fixed hairsprings 12, is schematically shown.

[0058] Reference Figures 1 to 4 is made to the device 100, Figures 1 to 4 which is schematically shown in different states during the operation of separating the hairsprings 12.

[0059] The device 100 includes a support 110 configured to receive and hold the assembly 10 during the separation operation.

[0060] More specifically, the support 110 includes a base or body 111 and a main shaft 112 extending perpendicular to the general plane formed by the body 111.

[0061] The main shaft 112 has a plurality of notches 113 at its free end. Preferably, the number of notches is greater than or equal to the number of wound spiral springs forming the assembly 10. Thus, in the illustrated exemplary embodiment, the main shaft 112 includes four notches 113 uniformly distributed around the circumference of the main shaft 112.

[0062] Preferably, the free end that at least partially bears these notches 113 has a conical profile to facilitate the positioning of the assembly 10 or the removal of the individual separated hairsprings 12.

[0063] The notches 113 are configured to receive the inner wire harness 13 of the wound hairspring 12 and hold the assembly 10 at a certain distance from the body 111. Thus, the individual wound hairsprings 12 of the assembly 10 are held in the device 100 only by the inner wire harness forming the inner end of the wound hairspring 12, and the individual coils of the wound hairspring 12 are suspended above the body 111 of the support 110.

[0064] The device 100 includes a vibrating table 120 that vibrates along two different axes extending in the same plane, which defines Figure 4 the shown vibration plane P1.

[0065] Preferably, the two vibration axes are orthogonal to each other.

[0066] The vibrating table 120 moves in a circular translation manner within the vibration plane P1, as Figure 4 shown.

[0067] "Circular translational motion" is defined as the following planar motion: the trajectories of all points on the vibrating table 120 are circles with the same radius but different centers.

[0068] The vibrating table 120 generates vibrations through the mechanical drive of a motor (not shown), such as a pneumatic motor or a piezoelectric motor.

[0069] The motor causes the vibrating table 120 to vibrate at a frequency between 1,000 Hz and 12,000 Hz, preferably at a frequency between 4,000 Hz and 8,000 Hz, such as at a frequency of 6,000 Hz.

[0070] The amplitude, frequency, and vibration power of the vibrating table 120 can be modified via a human-machine interface (not shown).

[0071] The vibrating table 120 is integrated with the main body 111 such that the support member 110 also vibrates in a plane parallel to the vibration plane P1.

[0072] The device 100 further includes a removable cover 150 or lid configured to at least partially cover the free end of the main shaft 112 in order to limit the axial movement of the assembly 10 and the separated hairspring 12 along the longitudinal axis z of the main shaft 112 when the support member 110 vibrates.

[0073] The removable cover 150 includes an opening or recessed area that is indented relative to its lower surface (i.e., the surface facing the vibrating table 120). This opening or recessed area forms a groove 151 configured to receive the free end of the main shaft 112 when the removable cover 150 is in the closed position.

[0074] The removable cover 150 is movable between a closed position and an open position, where the closed position restricts the movement of the hairspring along the z-axis of the main shaft 112 and prevents the hairspring 12 from detaching from the main shaft 112 of the support member 110, while the open position allows the assembly 10 with the wound hairspring to be inserted onto the support member 110 and also allows the hairspring 12 to be removed after separation.

[0075] Preferably, the removable cover 150 is translatable along an axis perpendicular to the vibration plane P1 of the vibrating table 120. Preferably, the translation axis of the removable cover 150 coincides with the longitudinal axis z of the main shaft 112.

[0076] The device 100 further includes an ejector for removing the separated hairspring 12 from the support member 110 in order to prepare for a new cycle of separating the assembly 10. Preferably, the ejector 130 is an air ejector, such as a compressed air ejector.

[0077] The device 100 further includes a collection tray 140 for recovering and collecting the individual ejected hairsprings 12.

[0078] The present invention also relates to a method 200 for manufacturing a hairspring intended to equip the balance wheel of a watch movement, the method comprising at least one step 260 of separating the wound and thermally fixed hairspring, which step is carried out by means of the device 100 according to the invention.

[0079] Reference Figure 5 The main steps of the manufacturing method 200 are given.

[0080] The manufacturing method 200 comprises the following successive steps:

[0081] - Step 210: Producing a blank made of an alloy, which alloy is preferably a compensating alloy, more particularly a titanium alloy, preferably an alloy comprising niobium and titanium,

[0082] - Step 220: Applying to the said alloy a processing sequence of coupled deformation - precipitation heat treatment, which processing sequence comprises alternately applying deformation and heat treatment until the desired microstructure is obtained,

[0083] - Drawing step 230: Carrying out this step until a wire with a round cross - section is obtained and rolling to produce a rectangular profile compatible with the inlet cross - section of the drawing spindle or the star piece,

[0084] - Winding step 240: This step comprises winding a plurality of rolled wires in a barrel by means of a winding spindle or a star piece, thereby forming an assembly 10 of wound hairsprings 12, wherein the individual hairsprings 12 are wound in the same plane,

[0085] - Expansion step 250: Releasing the stress in the assembly 10 of wound hairsprings 12 in order to fix the final Archimedean spiral shape of the hairsprings 12 by means of an expansion cycle.

[0086] The manufacturing method 200 also comprises a step 260 of separating each of the wound hairsprings that have been thermally fixed during step 250. This separation step 260 is carried out by the device 100 in the following manner:

[0087] - In Figure 1 In a first sub - step 261, more particularly shown, the assembly 10 formed of a plurality of wound and thermally fixed hairsprings 12 is positioned on the mandrel 112 of the support 110 so as to position the inner wire bundle 13 in the notch 113 of the main spindle 112; thereby suspending the assembly 10 in the device 100, the assembly 10 being held only by the inner wire bundle 13 of the wound hairsprings 12;

[0088] - In Figure 2In the second sub-step 262 shown more specifically, the removable cover 150 is lowered to a closed position to prevent the component 10 mounted on the main shaft 112 from falling; the support 110 is vibrated by the shaker 120 to generate a circular translational motion in a plane parallel to the plane of the hairspring 12; subsequently, the hairsprings 12 are separated from each other and no longer lie in the same plane;

[0089] - In Figure 3 In the third sub-step 263 shown more specifically, the removable cover 150 is lifted to an open position, and the air ejector 130 generates an air flow to eject the separated hairsprings 12; the final hairsprings 12 are collected in the collection tray 140.

Claims

1. A separation device (100) for separating an assembly (10) of a balance spring (12) which has been wound and has undergone an expansion cycle, the separation device (100) comprising: - a support (110) comprising a notch (113) for receiving the inner strand (13) of the wound balance spring (12) constituting the assembly (10), - a vibration table (120) movable along two different vibration axes extending in the same plane and defining a vibration plane (P1), the vibration table (120) being configured to vibrate the support (110) in a plane parallel to the vibration plane (P1).

2. The separation device (100) according to claim 1, characterized in that: The two vibration axes are orthogonal.

3. The separation device (100) according to any one of the preceding claims, characterized in that The vibration table (120) vibrates in a circular translational motion.

4. The separation device (100) according to any one of the preceding claims, characterized in that The support member (110) includes a main body (111) integral with the vibration table (120), and a main shaft (112) integral with the main body (111), the main shaft extending perpendicularly to a vibration plane (P1) of the main body (111) and the vibration table (120).

5. The separation device (100) according to claim 4, characterized in that: The notch (113) is formed at the free end of the main shaft (112).

6. The separation device (100) according to claim 5, characterized in that: The free end of the main shaft (112) is conical.

7. The separation device (100) according to any one of the preceding claims, characterized in that The separation device (100) comprises an air ejector (130) for ejecting the separated hairspring (12) when the vibration table (120) vibrates.

8. The separation device (100) according to claim 7, characterized in that: The separation device (100) comprises a collecting tray (140) for receiving the ejected balance spring (12).

9. The separation device (100) according to any one of claims 5 to 8, characterized in that: The separation device (100) includes a removable cover (150) configured to at least partially cover a free end of the spindle (112).

10. The separation device (100) according to claim 9, characterized in that: The removable cover (150) is movable between a closed position, wherein the closed position prevents the hairspring (12) from being removed from the support (110), and an open position, wherein the closed position allows the assembly (10) of the wound hairspring (12) to be inserted into the support (110) and the separated hairspring (12) to be removed from the support (110).

11. The separation device (100) according to claim 10, characterized in that The removable cover (150) is capable of translation along an axis perpendicular to a vibration plane (P1) of the vibration table (120).

12. The separation device (100) according to any one of claims 10 to 11, characterized in that: The removable cover (150) includes a recess (151) configured to receive a free end of the spindle (112) when the removable cover is in a closed position.

13. The separation device (100) according to any one of the preceding claims, characterized in that The separation device (100) comprises a motor configured to vibrate the vibration table (120) at a frequency between 1,000 Hz and 12,000 Hz, preferably between 4,000 Hz and 8,000 Hz.

14. The separation device (100) according to claim 13, characterized in that The motor is a pneumatic motor or a piezoelectric motor.

15. A method (200) for manufacturing a hairspring intended to be equipped with a balance wheel of a watch movement, characterized in that: The manufacturing method (200) comprises a separation step (260) for separating the assembly (10) of wound balance springs (12) that have undergone an expansion cycle, the separation step being performed by operating a separation device (100) according to any one of the preceding claims.

16. The method (200) for manufacturing a hairspring intended to equip a balance wheel of a watch movement according to claim 15, characterized in that: The manufacturing method (200) comprises, before the separation step (260), a winding step (240), which comprises winding a plurality of rolled wires into a barrel (2) by means of a winding star, so as to form an assembly (10) of wound balance springs (12).

17. The method (200) for manufacturing a hairspring intended to equip a balance wheel of a watch movement according to claim 16, characterized in that: The manufacturing method (200) comprises, after the winding step (240), an expansion step (250) for relieving stress in the assembly (10) of the wound balance spring (12).

18. A method (200) for manufacturing a hairspring intended to equip a balance wheel of a watch movement according to any one of claims 15 to 17, characterized in that: The balance spring (12) is a compensation spring.

19. The method (200) for manufacturing a hairspring intended to equip a balance wheel of a watch movement according to claim 18, characterized in that: The hairspring (12) is made of niobium-titanium alloy.

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