Hairspring for a time regulator member, equipped with temperature-dependent adjustment means

Abstract

To provide a balance spring for a horological regulating member, the balance spring being provided with temperature-dependent adjustment means.SOLUTION: The present invention relates to a balance spring, in particular, for a horological regulating member, the balance spring (100) including a flexible strip (2) wound about its own axis multiple turns, the strip (2) having a predefined stiffness. The balance spring (100) has means of adjusting the stiffness of the strip (2) The balance spring (1) also has actuating means (10) for actuating the adjustment means, the actuating means (10) being configured to actuate the adjustment means depending on ambient temperature. The invention also relates to a horological regulating member including such balance spring.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a hairspring for a timepiece speed control member, the hairspring being provided with temperature-dependent adjustment means. The present invention further relates to a timepiece speed control member provided with such a hairspring.

Background Art

[0002] In most mechanical watches, the energy required for the rotation of the hands (e.g., the minute hand and the hour hand) is stored in a barrel and then delivered by a hairspring-wheel system, the hairspring-wheel system comprising a pallet wheel called a wheel, the wheel being combined with a spring in the form of a strip wound in a spiral shape called a hairspring.

[0003] The inner end of the hairspring is attached to the fusee that rotates the hairspring together with the wheel, the outer end of the hairspring is attached to the hairspring holder, the hairspring holder is assembled on the hairspring holder receiver, and the hairspring holder receiver itself is rigidly connected to a fixed stud.

[0004] By the escapement mechanism, the rotation of the wheel is maintained and the vibrations of the wheel are counted, the escapement mechanism comprising an anchor lever driven by a low-amplitude oscillatory motion, the anchor lever comprising two anchors that engage with the teeth of the escape wheel. When the escape wheel engages in this way, the escape wheel is rotated step by step, and the rotational speed of the escape wheel is determined by the oscillation frequency of the anchor lever. The anchor lever itself is set to the oscillation frequency of the hairspring-wheel.

[0005] In a conventional escapement mechanism, the oscillation frequency is about 4 Hz, or about 28,800 vibrations per hour (V / h). One of the aims of excellent watch manufacturers is to ensure the isochronism and regularity of the vibrations of the wheel (or the stability of the speed of the wheel).

[0006] The speed of the balance wheel can be regulated in known ways by adjusting the effective length of the hairspring, which is defined as the length of the curve between the inner end of the hairspring and the counterpoint, and is defined by a pair of stoppers located near the outer end of the hairspring and typically supported by keys mounted on the regulator system.

[0007] During operation, this regulator system cannot rotate around the axis of the hairspring. However, the angular position of the regulator system can be finely adjusted by human intervention, for example, by using a screwdriver to pivot an eccentric that acts like a cam on the regulator system.

[0008] An assembly comprising a stopper, a regulator system, a key, a hairspring holder, a hairspring holder, a balance staff, a mainspring, and a balance wheel is generally called a “regulating member.” Examples of regulating members are shown in International Publication No. 2016 / 192957 and European Patent Application Publication No. 2876504, both filed by the watchmaker ETA.

[0009] There is a regulator system with a hairspring holder to which the end of the hairspring is attached, and the key of the regulator system leaves enough play that the hairspring can move between two rests. However, the timekeeping characteristics, in particular the anochronism which changes with amplitude, are quite sensitive to the play in the regulator key, and this play is difficult to control precisely.

[0010] In some devices, the hairspring can be stopped by adjusting a stop mechanism, particularly to eliminate play while the hairspring is running. In this case, the speed is first regulated by moving the regulator key, and then the hairspring is stopped by the key. However, stopping the hairspring by the regulator key puts stress on the hairspring, and there is a risk of causing errors in time measurement, especially because the center of the winding shifts. Furthermore, eliminating play also changes the speed, and once the hairspring is stopped, it is no longer possible to move the regulator key along the hairspring to fine-tune the speed.

[0011] Other hairsprings have an integrated regulating device. In these hairsprings, the speed is regulated not by changing the effective length of the hairspring, but by applying force or torque to an elastic element placed in series with the hairspring. More specifically, the flexible element is placed in series with the strip between the end of the strip and the fixed support, modifying the stiffness of the mounting point and making the resonator more flexible. Thus, the effective stiffness of the resonator includes the stiffness of the strip and the stiffness of the flexible element.

[0012] In this case, the variable force or torque is applied in such a way that stress is applied to the flexible element. By applying stress to the flexible element, the stiffness of the flexible element changes, while the stiffness of the strip remains unchanged, thereby partially obtaining the return force acting on the balance wheel. By modifying the stiffness of the flexible element, the overall stiffness of the resonator (stiffness of the strip and stiffness of the flexible element) changes, which in turn modifies the speed of the resonator and allows for precise adjustment of the time-referenced frequency. Because only one element is used to adjust the stiffness, this results in high precision during speed control.

[0013] Such a hairspring having an elastic element is described, for example, in European Patent Application Publication No. 4009115 filed by Omega SA.

[0014] However, ambient temperature significantly affects the speed of a speed regulator that includes such a hairspring and flywheel. This is because the balance wheel and / or hairspring expand or contract in response to ambient temperature. Variations in these dimensions result in variations in the speed regulator's speed.

[0015] Furthermore, since the elastic modulus also changes with ambient temperature, it alters the rigidity of the hairspring.

[0016] To mitigate these fluctuations, speed regulators have been developed that are configured to compensate for the effects of temperature. For example, when using a bimetallic balance wheel, or in the case of a silicon hairspring, a silicon oxide layer having a thermoelastic modulus opposite to that of the silicon used to fabricate the hairspring is added (see European Patent No. 1422436).

[0017] However, these configurations are only effective around a predetermined temperature range, and are no longer sufficiently effective when the temperature deviates from this range. [Prior art documents] [Patent Documents]

[0018] [Patent Document 1] International Publication No. 2016 / 192957 [Patent Document 2] European Patent Application Publication No. 2876504 [Patent Document 3] European Patent Application Publication No. 4009115 [Patent Document 4] European Patent No. 1422436 [Overview of the project] [Problems that the invention aims to solve]

[0019] The object of the present invention is to overcome some or all of the above-mentioned drawbacks by providing a hairspring equipped with an effective adjustment means, in particular to minimize the sensitivity of the speed regulator to changes in ambient temperature, and the adjustment means adapts to ambient temperature even when temperature fluctuations are significant. [Means for solving the problem]

[0020] For this purpose, the present invention relates in particular to a hairspring for a timepiece speed control member, the hairspring comprising a flexible strip wound a plurality of times around its own axis, the strip having a predefined stiffness, the hairspring comprising means for adjusting the stiffness of the strip, and the hairspring comprising actuating means for actuating the adjusting means.

[0021] The present invention is characterized in that the actuating means actuates the adjusting means as a function of the ambient temperature.

[0022] Thanks to the actuating means, variations in the dimensions of the hairspring and / or the balance wheel due to temperature, as well as thermoelastic variations of the hairspring, are compensated for, and in particular, the secondary influence of temperature on the speed of the speed control member is compensated for. Thus, variations in the speed of the speed control member comprising the hairspring and the escapement wheel resulting from temperature variations are prevented.

[0023] According to a particular embodiment of the present invention, the actuating means comprise a deformable element that depends on temperature.

[0024] According to a particular embodiment of the present invention, the deformable element comprises a temperature-sensitive material.

[0025] According to a particular embodiment of the present invention, the deformable element is a bimetallic additive.

[0026] According to a particular embodiment of the present invention, the deformable element comprises a microstructure or even a nanostructure.

[0027] According to a particular embodiment of the present invention, the actuating means comprise a support that can be moved by the deformable element and that moves the support to a plurality of positions as a function of the deformation of the deformable element.

[0028] [[ID=三十二]]According to a particular embodiment of the present invention, the adjusting means comprise a flexible element arranged in series with the strip, the flexible element connecting one end of the strip to a fixed support so as to apply additional stiffness to the strip, and the flexible element preferably having a stiffness that exceeds that of the strip.

[0029] According to a particular embodiment of the present invention, the adjustment means includes a stress application means for applying a variable force or torque to a flexible element in order to change the stiffness of the flexible element.

[0030] According to a particular embodiment of the present invention, the support comes into contact with the stress application means.

[0031] According to a particular embodiment of the present invention, the support comprises a rod, the rod having a first end that is mounted on a deformable element and a second end that is mounted on a stress-applying means.

[0032] According to a particular embodiment of the present invention, the actuation means comprises a fixing pin that allows a rod to form a lever.

[0033] According to a particular embodiment of the present invention, the flexible element comprises two flexible components, each of which connects a strip to a fixed support, and the two flexible components are arranged axially symmetrically with respect to each other along an axis, which preferably substantially passes through the center of the hairspring.

[0034] According to a particular embodiment of the present invention, the stress application means comprises two flexible levers, each connected to a flexible component.

[0035] According to a particular embodiment of the present invention, the two levers are connected to each other by a movable body.

[0036] The present invention further relates to a speed regulating member, particularly for a timekeeping instrument movement, the speed regulating member comprising an oscillating weight and such a hairspring.

[0037] The object, advantages, and features of the present invention will become apparent from reading several embodiments provided for illustrative purposes only and shown with reference to the accompanying drawings. These embodiments are not intended to limit the scope of the present invention. [Brief explanation of the drawing]

[0038] [Figure 1] This is a schematic top view of a hairspring according to a first embodiment of the present invention, and the hairspring has the first configuration. [Figure 2] Figure 1 is a schematic top view of the hairspring, which is located in the second component. [Figure 3] Figure 1 is a schematic top view of the hairspring, which is located in the third component. [Figure 4] This graph shows the effect of temperature control measures on temperature fluctuations. [Figure 5] This is a schematic top view of a hairspring according to a second embodiment of the present invention. [Figure 6] This is a schematic top view of a hairspring according to a third embodiment of the present invention. [Modes for carrying out the invention]

[0039] Figures 1 to 3 schematically illustrate first embodiments of the hairspring 1, particularly for the timekeeping instrument speed regulator. The three figures show three different configurations of the hairspring 1.

[0040] In this case, the hairspring 1 extends substantially within a single plane. The hairspring 1 includes a flexible strip 2 that is wound multiple times around its axis, and the strip 2 has a predetermined rigidity.

[0041] The hairspring is provided with means for adjusting the rigidity of strip 2. For example, the adjustment means may be operated in particular when assembling the hairspring into the regulating member, and in particular when assembling it on the plate of the timekeeping movement.

[0042] The adjustment means comprises a flexible element 5 arranged in series with the strip 2, the flexible element 5 being integral with the outer end 4 of the strip 2 and connecting to a fixed support 53. The flexible element 5 adds further rigidity to the rigidity of the strip 2. The flexible element 5 is preferably stiffer than the strip 2. The flexible element 5 is positioned behind the strip 2 and connected to the strip 2. Preferably, the adjustment means 5 and the strip 2 are integral parts or further made from the same material. The hairspring 1 further includes a stress application means 6 for applying a variable force or torque to the flexible element 5. Thus, the rigidity of the hairspring 1 can be adjusted, in particular to improve the accuracy of the movement's speed.

[0043] In this embodiment of the hairspring, the flexible element 5 comprises two flexible parts 15 and 16, each connecting the strip 2 to a fixed support 53.

[0044] The two flexible components 15 and 16 are arranged axially with respect to each other along the axis A of the hairspring 1. In other words, the two flexible components 15 and 16 are arranged symmetrically with respect to the axis A.

[0045] On the one hand, axis A substantially passes through the center O of the hairspring, and on the other hand, axis A preferably passes through the outer end 4 of the strip 2.

[0046] Therefore, the two flexible parts 15 and 16 are positioned on the outer circumference of the hairspring, such that the two flexible parts 15 and 16 are positioned at the same distance from the center O of the hairspring 1.

[0047] The two flexible parts 15 and 16 are preferably positioned "mirror-like" relative to each other with respect to axis A. For this purpose, the two flexible parts 15 and 16 are preferably substantially identical.

[0048] Each of the flexible components 15 and 16 is equipped with a curved flexible vane 55, which preferably forms a semicircle and extends from the end of the fixed support 53. Each curved flexible vane 55 is also connected to the outer end 4 of the strip 2 by a main flexible vane 7. In this case, the main flexible vane 7 is arranged continuously with the curved flexible vanes 55.

[0049] The curved blade 55 forms a semi-circular curved section, extending at one end by a single flexible blade 7 and at the other end by a fixed support 53. The end 56 of the support itself forms a complementary curved section opposite to the curved section of the curved blade 55. The end 56 of the support 53 is semi-rigid so as to be partially deformable.

[0050] This configuration of the curved section and complementary curved section prevents the isochronism of the speed regulator from being altered when the speed is corrected using the adjustment means. More specifically, the force applied to the upper part of the curved blade 55 is compensated by the reaction force of the complementary curved section at the end 56, as indicated by the arrows in Figure 14. Thus, only the single flexible blade 7 receives the force or torque applied by the stress application means 6.

[0051] The fixed support 53 has an open trapezoidal shape on its longer side, which is directed toward the outer end 4 of the strip 2.

[0052] The means for adjusting the hairspring 1 further includes a stress application means 6 for applying a variable force or torque to the flexible element 5. In this way, the stiffness of the hairspring 1 can be adjusted. The torque or force is continuously adjustable for the stress application means 6. In other words, the torque or force is not limited to a single value. Therefore, the stiffness of the flexible element 5 can be adjusted with great precision.

[0053] Preferably, the stress application means 6 applies substantially identical force or torque to each flexible component 15, 16 via two levers 14, 26 by a single force F applied to the third body 19. The direction of the force is preferably substantially symmetric with respect to axis A.

[0054] The stress application means 6 further comprises two levers 14 and 26, each connecting a curved vane 55 to the same, preferably rigid, movable body 19, which is positioned on the opposite side of the hairspring 1 from the fixed support 53. In this case, the movable body 19 is arc-shaped.

[0055] A variable force or torque is applied to the movable body 19. The variable force or torque is transmitted, at least partially, via levers 14 and 26 to the main flexible vanes 7 of the flexible parts 15 and 16 of the flexible element 5.

[0056] Preferably, the torque or force is continuously adjustable thanks to the stress application means 6. In other words, the torque or force is not limited to a single value. Therefore, the stiffness of the flexible element 5 can be adjusted with great precision.

[0057] The hairspring 1 further includes an actuation means 10 for acting on the stress application means 6.

[0058] According to the present invention, the actuation means 10 acts on the stress application means 6 in accordance with the ambient temperature. Therefore, the actuation means 10 acts on the hairspring 1 and compensates for the effects of temperature changes on the speed regulator by correcting the stiffness in order to maintain the speed regulator at a constant speed.

[0059] For this purpose, the actuation mechanism 10 includes an element 11 that can be deformed in response to temperature. The deformable element 11 has the advantage of deforming in response to temperature in a controlled manner.

[0060] In an alternative embodiment, the deformable element 11 comprises a deformable liquid or semiliquid element, such as mercury or alcohol, used, for example, in a thermometer. This liquid or semiliquid element is housed in a housing with a movable wall, which moves in response to the deformation of the liquid or semiliquid element, which changes with temperature.

[0061] Alternatively, the deformable element 11 is a metal that is highly sensitive to temperature.

[0062] The operating means 10 further comprises a support 12 that contacts the stress applying means 6, in this case the movable body 19. The support 12 also contacts the deformable element 11. Therefore, the support 12 is movable by the deformable element.

[0063] For example, if the deformable element is a liquid or semi-liquid, the support 12 comes into contact with the movable wall, thereby moving the support 12 in accordance with the deformation of the deformable element 11.

[0064] In the case of a metallic material, the support 12 is in direct contact with the metallic material.

[0065] In the drawing, the support 12 comprises a rod 13 that forms a lever for the stress application means 6. The rod 13 has two ends 17 and 18, the first end 17 being mounted on the deformable element 11 and the second end 18 being mounted to the stress application means 6.

[0066] The actuation mechanism 10 further comprises a pin 21, which is intended to remain stationary relative to the base of the speed regulator, and the rod 13 may come into contact with the pin 21. The pin 21 acts as a support point, allowing the rod to form a lever. The pin 21 also forms a reference point for the speed of the speed regulator.

[0067] The pin 21 is located, for example, approximately in the middle of the rod 13. Therefore, when the rod 13 comes into contact with the pin 21, the rod 13 leans against the pin 21, transmitting the force caused by the deformation of the deformable element 11.

[0068] Preferably, the pin 21 has a non-circular cross-section for adjusting the operation of the deformable element 11.

[0069] In Figure 1, the rod 13 is in contact with the movable body 19 of the stress application means 6 and is supported by the pin 21. The rod 13 applies force to the movable body 19 so that a predetermined stiffness is obtained for the hairspring 1. For example, the predetermined stiffness is selected for an ambient temperature of 20 degrees.

[0070] In an alternative embodiment, the pin 21 is offset from the center of the rod 13 so as to have a greater stress center distance when the rod 13 is actuated.

[0071] In the configuration shown in Figure 2, the deformable element 11 expands as a result of the higher temperature. The deformable element 11 pushes back against the rod 13, and the rod 13 is no longer in contact with the pin 21. As the force applied to the moving body 19 increases, the stiffness of the flexible element 5 changes.

[0072] Therefore, the effect of temperature rise on the speed-regulating member is compensated for by the increase in force applied to the stress application means 6.

[0073] In the configuration shown in Figure 3, the ambient temperature decreases, causing the deformable elements to contract. As a result, the rod 13 not only returns to the pin 21, but also pushes back the movable body 19 due to the lever action. More specifically, as the rod presses against the pin 21, the second end presses against the movable body 19 of the stress application means 6.

[0074] As a result, the stiffness of the flexible element 5 is modified to compensate for the effect of the ambient temperature decrease on the speed-regulating member.

[0075] In either case, regardless of whether the ambient temperature is decreasing or increasing, the actuation means 10 presses the movable body 19 to correct the rigidity of the flexible element 5.

[0076] In Figure 4, the graph shows three superimposed curves 22, 23, and 24, illustrating the effect of temperature on the speed control element.

[0077] The curve 24 below represents the temperature-dependent variation in velocity without compensation according to the present invention. Thus, as the temperature increases or decreases, the difference in velocity compared to the velocity at 23°C decreases. Such a curve can be achieved with a hairspring described in patent EP1605182.

[0078] The curve 22 above represents the speed fluctuation obtained by the operating means 10 according to the present invention.

[0079] The intermediate curve 23 represents the effect obtained on the speed of the speed regulator by the operating means 10 according to the present invention when the ambient temperature fluctuates. The speed remains almost constant despite significant temperature fluctuations.

[0080] More specifically, thanks to the actuation mechanism 10, the action of the actuation mechanism 10 shown in the upper curve 22 compensates for the effects of temperature fluctuations shown in the lower curve 24, keeping the speed nearly constant despite the temperature difference.

[0081] A second embodiment of the hairspring 1 is shown in Figure 5, and the hairspring 1 is substantially identical to that of the first embodiment, except for the deformable element 27 of the adjustment means 10. In this case, the deformable element 27 comprises a bimetallic adduct that deforms in accordance with temperature.

[0082] The bimetallic appendage is curved and has a first end 29, which is assembled to a fixed support 31 located outside the hairspring 1. The second end 28 of the bimetallic appendage is associated with the first end 17 of the rod 12. The second end 28 of the bimetallic appendage is in contact with the first end 17 of the rod 12.

[0083] As the ambient temperature changes, the bimetallic appendage bends to varying degrees. Consequently, the second end 28 of the bimetallic appendage pushes and pulls the first end 17 of the rod 12, activating the stress application means 6.

[0084] As a result, the rod 13 moves in accordance with the curvature of the bimetallic adduct, similar to the rod 13 in the first embodiment.

[0085] Such bimetallic adducts are well known to those skilled in the art.

[0086] In the third embodiment shown in Figure 6, the deformable element 28 comprises a microstructure or nanostructure, such as a honeycomb structure, that deforms in response to temperature. Such a microstructure or nanostructure is configured to deform in the same manner as in the first embodiment.

[0087] As a result, the rod 13 moves in accordance with the deformation of the microstructure or nanostructure, similar to the rod 13 in the first embodiment.

[0088] The flexible blades described in various embodiments of the hairspring may be continuous flexible blades, as is typical in the drawings, or blades having flexible collars connecting rigid sections.

[0089] The present invention further relates to a speed-regulating member (not shown), particularly for a timekeeping movement. The speed-regulating member comprises, for example, an oscillating weight and the aforementioned balance spring. The oscillating weight is, for example, an annular balance wheel. The oscillating weight is joined to the balance spring such that the oscillating weight is integral with a support. [Explanation of symbols]

[0090] 1. Whiskers 2 Flexible strip 4 ends 6. Stress application means 9 End 10 Operating means 11 Deformable elements 12 Support 13 Bar material 14 Flexible lever 15 Flexible parts 16 Flexible parts 17 First end 18. Second end 19 Movable body 21 Fixing pins 26 Flexible lever 53 Fixed support

Claims

1. A hairspring for a time measuring instrument speed regulator, wherein the hairspring (1) comprises a flexible strip (2) wound multiple times around its axis, the flexible strip (2) having a predetermined rigidity, the hairspring (1) comprising an adjustment means for adjusting the rigidity of the flexible strip (2), and the hairspring (1) comprising an actuation means (10) for acting on the adjustment means, wherein the actuation means (10) acts on the adjustment means according to the ambient temperature. The operating means (10) includes a deformable element (11) that can be deformed according to the ambient temperature. The actuation means (10) comprises a support (12), the support (12) can be moved by the deformable element (11), and moves the support (12) to a plurality of positions in accordance with the deformation of the deformable element (11), The adjustment means comprises a flexible element (5) arranged in series with the flexible strip (2), the flexible element (5) connects the ends (4, 9) of the flexible strip (2) to a fixed support (53) so as to add further rigidity to the flexible strip (2), and the flexible element (5) has rigidity exceeding that of the flexible strip (2). The adjustment means includes a stress application means (6) that applies a variable force or torque to the flexible element (5) so as to change the rigidity of the flexible element (5). The hairspring is characterized in that the flexible element (5) comprises two flexible parts (15, 16), each of the two flexible parts (15, 16) connecting the flexible strip (2) to the fixed support (53), the two flexible parts (15, 16) being arranged symmetrically in the axial direction with respect to each other along an axis (A), and the axis (A) passing through the center (O) of the hairspring.

2. The hairspring according to claim 1, characterized in that the deformable element (11) is made of a temperature-sensitive material.

3. The hairspring according to claim 1, characterized in that the deformable element (11) comprises a bimetallic adduct.

4. The hairspring according to claim 1, characterized in that the deformable element (11) comprises a microstructure or a nanostructure.

5. The hairspring according to claim 1, characterized in that the support (12) is in contact with the stress application means (6).

6. The hairspring according to claim 5, characterized in that the support (12) comprises a rod (13), the rod (13) comprising a first end (17) assembled on the deformable element (11) and a second end (18) assembled on the stress applying means (6).

7. The hairspring according to claim 6, characterized in that the actuation means (10) includes a fixing pin (21) that enables the rod (13) to form a lever.

8. The hairspring according to claim 1, characterized in that the stress applying means (6) comprises two flexible levers (14, 26) each connected to the flexible components (15, 16).

9. The hairspring according to claim 8, characterized in that the two flexible levers (14, 26) are connected to each other via a movable body (19).

10. A hairspring for a time measuring instrument speed regulator, wherein the hairspring (1) comprises a flexible strip (2) wound multiple times around its axis, the flexible strip (2) having a predetermined rigidity, the hairspring (1) comprising an adjustment means for adjusting the rigidity of the flexible strip (2), and the hairspring (1) comprising an actuation means (10) for acting on the adjustment means, wherein the actuation means (10) acts on the adjustment means according to the ambient temperature. The operating means (10) includes a deformable element (11) that can be deformed according to the ambient temperature. The actuation means (10) comprises a support (12), the support (12) can be moved by the deformable element (11), and moves the support (12) to a plurality of positions in accordance with the deformation of the deformable element (11), The adjustment means comprises a flexible element (5) arranged in series with the flexible strip (2), the flexible element (5) connects the ends (4, 9) of the flexible strip (2) to a fixed support (53) so as to add further rigidity to the flexible strip (2), and the flexible element (5) has rigidity exceeding that of the flexible strip (2). The adjustment means includes a stress application means (6) that applies a variable force or torque to the flexible element (5) so as to change the rigidity of the flexible element (5). The support (12) is in contact with the stress application means (6), The hairspring is characterized in that the support (12) comprises a rod (13), the rod (13) comprising a first end (17) assembled on the deformable element (11) and a second end (18) assembled on the stress applying means (6).

11. A speed regulating member for a timekeeping instrument movement, comprising a vibrating weight, wherein the speed regulating member comprises a hairspring (1) as described in claim 1 or 10.

Images