REGULATOR ORGAN FOR CLOCK MOVEMENT WITH COIL SPRING, EQUIPPED WITH TEMPERATURE COMPENSATORS

Description

Technical field of the invention

[0001] The invention relates to a spring-spiral regulating organ equipped with temperature compensation means, particularly for watchmaking. Technological background

[0002] Most modern mechanical watches feature a balance wheel and hairspring, and a Swiss lever escapement mechanism. The balance wheel and hairspring form the watch's timekeeping base. It is also called the resonator or regulating organ.

[0003] The exhaust system, for its part, fulfills two main functions: to maintain the back-and-forth movement of the resonator: to count these back-and-forth movements.

[0004] To construct a mechanical resonator, one needs an inertial element, a guide, and an elastic return element. Traditionally, a balance spring acts as the elastic return element for the inertial element, which is a balance wheel. This balance wheel is guided in rotation by pivots, which generally rotate in ruby ​​plain bearings.

[0005] A frequency is chosen for the mechanical resonator, which is determined to obtain a predefined rate for the clockwork movement.

[0006] However, during its operation, such a mechanical resonator can be subject to disturbances caused by changes in external parameters, which generate variations in the resonator's frequency. These parameters include, for example, temperature, pressure, humidity, and gravity. The resulting frequency variation in the resonator leads to an error in time measurement and therefore in the accuracy of the clockwork mechanism.

[0007] Document CH 704687 describes a regulating device comprising a spiral spring and a pin position correction device to correct spiral spring deformations due to certain parameters, in particular temperature.

[0008] However, such a correction mechanism does not achieve the desired level of precision. Document EP 4 009 115 A1 describes a rate-adjusting device comprising an elastic element in series at the outer end of the balance spring and preload means applying a variable force to the elastic element. Summary of the invention

[0009] The aim of the present invention is to overcome all or part of the aforementioned disadvantages by proposing a spring-spring clock regulating organ equipped with more precise temperature compensation means.

[0010] For this purpose, the invention relates to a rotary regulating organ for a clock movement comprising an oscillating mass, for example a balance wheel, a balance spring comprising a flexible ribbon wound on itself in several turns, the ribbon having a predefined rigidity to allow the oscillating mass to perform a rotary oscillatory movement, the ribbon comprising an external end.

[0011] The invention is remarkable in that the regulating organ includes an elastic temperature compensation device configured to adapt its stiffness according to the temperature in order to compensate for the effect of temperature on the regulating organ, the elastic device comprising an elastic element connecting the external end to a first support fixed relative to the clock movement, as well as pre-stressing means for applying a variable force or torque on the elastic element according to the temperature.

[0012] Thanks to the invention, the preload means exert a variable force or torque on the elastic element depending on the temperature, so that the regulating device maintains a substantially precise operation despite significant temperature changes. Indeed, when the temperature changes, the preload means modify the force or torque exerted on the elastic element, thereby changing the stiffness of the assembly comprising the elastic element and the spiral spring. By modifying the stiffness of this assembly, the operation of the regulating device is adjusted. Consequently, when the temperature changes, the elastic device is mechanically impacted to adjust the operation of the spiral spring to this change.

[0013] This elastic element modifies the stiffness of the attachment point and provides additional flexibility to the resonator. Thus, the effective stiffness of the resonator comprises the stiffness of the ribbon and the stiffness of the elastic element. The variable force or torque allows the elastic element to be pre-stressed, preferably without pre-stressing the ribbon and without moving the ribbon end. By pre-stressing the elastic element, its stiffness changes, while the stiffness of the ribbon remains unchanged, since it is not pre-stressed and its end does not move.

[0014] By changing the flexibility of the elastic element, the rigidity of the resonator (ribbon rigidity and elastic element rigidity) changes, which consequently alters the resonator's behavior. Since the elastic element is preferably more rigid than the ribbon, its contribution to the overall rigidity is less than that of the ribbon. Therefore, changing the elastic element's rigidity modifies the rigidity of the entire resonator, thus fine-tuning its behavior and allowing for precise adjustment of our timebase frequency. This results in high accuracy in maintaining the resonator's behavior as a function of temperature.

[0015] According to a particular embodiment of the invention, the prestressing means comprise a spring part connected to the elastic element, the spring part transmitting the force or torque to the elastic element.

[0016] According to a particular embodiment of the invention, the prestressing means comprise a temperature-deformable body, the deformable body being at least partly in contact with the spring part during deformation.

[0017] According to a particular embodiment of the invention, the deformable body is an elongated bimetallic strip.

[0018] According to a particular embodiment of the invention, the spring part comprises a first flexible blade connected to the elastic element.

[0019] According to a particular embodiment of the invention, the spring part comprises a translation table connected to the first flexible blade, the deformable body being in contact with the translation table.

[0020] According to a particular embodiment of the invention, the spring part comprises a second flexible blade connected to the thermally deformable body.

[0021] According to a particular embodiment of the invention, the regulating organ extends substantially in the same plane.

[0022] According to a particular embodiment of the invention, the elastic element comprises a suspended point body and a pair of uncrossed blades connecting the suspended point body to the first stationary support.

[0023] According to a particular embodiment of the invention, the prestressing means are connected to the suspended point body to exert the force or torque on the suspended point body.

[0024] According to a particular embodiment of the invention, the regulating member includes means for adjusting the prestressing means to apply a variable force on the prestressing means, for example on the first moving element.

[0025] The invention also relates to a clock movement comprising such a regulating organ. Brief description of the figures

[0026] The aims, advantages and features of the present invention will become apparent from the reading of several embodiments given solely by way of non-limiting examples, with reference to the accompanying drawings in which: there figure 1 schematically represents a top view of a regulating device according to a first embodiment of the invention, and the figure 2 schematically represents a top view of a regulating organ according to a second embodiment of the invention. Detailed description of the invention

[0027] THE figures 1 and 2 represent two embodiments of a regulating organ according to the invention.

[0028] In both embodiments, the regulating member 1, 10 comprises a spiral spring equipped with a flexible ribbon 2 wound upon itself in several turns. The flexible ribbon 2 comprises an outer end 9 and an inner end 8.

[0029] The regulating organ 1, 10 comprises an oscillating mass, for example an annular balance wheel (not shown in the figures), which is connected to the inner end 8 of the ribbon 2. The ribbon 2 has a predefined rigidity to allow the oscillating mass to perform a rotary oscillatory motion. For example, the oscillating mass comprises an axial rotation shaft, the inner end 8 of the ribbon 2 being connected to said shaft.

[0030] Preferably, the regulating organ 1, 10 extends substantially in the same plane, except for the oscillating mass, which oscillates in a parallel plane, above the spiral spring.

[0031] According to the invention, the regulating member 1, 10 comprises an elastic device 50 for compensating an external parameter configured to adapt the stiffness of the elastic element 5 as a function of temperature in order to compensate for the effect of temperature on the regulating member 1, 10.

[0032] The elastic device 50 comprises an elastic element 5 connecting the outer end 9 to a fixed support 7 relative to the clockwork mechanism, for example, a plate. The elastic device 50 further comprises preload means 6 for applying a variable force or torque to the elastic element 5 depending on the external parameter.

[0033] The elastic element 5 here comprises a suspended point body 3 and a pair of uncrossed blades 4 connecting the suspended point body 3 to the stationary support 7. The suspended point body 3 is for example a cylindrical body of height substantially equal to the diameter, the uncrossed blades 4 spreading apart from the suspended point body 3 to the stationary support 7.

[0034] The elastic element 5 is arranged in the extension of the flexible ribbon 2, the spiral spring and the elastic element 5 being adjacent, but avoiding contact during the oscillation of the oscillating mass.

[0035] The prestressing means 6 are configured to exert the force or torque on the suspended point body 3. The prestressing means 6 comprise a spring part provided with a flexible blade 11 connected to the suspended point body 3. The first flexible blade 11 extends along the axis of the elastic element, tangentially to the spiral spring, and is slightly offset from the outer end 9.

[0036] In the first embodiment of the figure 1The spring portion of the prestressing means 6 comprises a translation table equipped with a first movable element 12 in the shape of an L and a second fixed support 13 relative to the movement. The first movable element 12 is connected to the flexible blade 11 by one end of a first arm of the L. The second arm of the L has a rounded protrusion 53 on its outer side. The translation table comprises two substantially parallel flexible blades 14 connecting the first movable element 12 to the second fixed support 13.

[0037] The prestressing means 6 further comprise a thermally deformable body 15 depending on the temperature, the deformable body 15 exerting the variable force or torque on the moving element 12.

[0038] In this example, the thermally deformable body 15 is a bimetallic strip whose deformation is caused by temperature. The bimetallic strip has a longitudinally extending body and comprises two elongated parts 51, 52 joined longitudinally. The two elongated parts 51, 52 are each made of a different material, with different thermal deformation properties. Thus, under the effect of heat, the bimetallic strip deforms laterally, one end 55 of the bimetallic strip being held in place, while the other end can move and deform the bimetallic strip to bend it to one side.

[0039] The bimetallic strip is positioned perpendicular to the moving element 12, such that a first free portion 54 is in contact with the protrusion 53 of the second arm of the L. The retained end 55 is held by a second translation table comprising a second moving element 18 and a second pair 17 of parallel flexible blades connecting the second moving element 18 to a third stationary support 19 relative to the movement plate. The second moving element 18 is L-shaped, with one arm of the L supporting the retained end 55 of the bimetallic strip, while the blades of the second pair 17 connect the inner face 56 of the second arm to the third stationary support 19. The blades of the second pair 17 are arranged perpendicular to the bimetallic strip in the rest position of the preload means 6.

[0040] In the event of a temperature change, the deformable body 15, here the bimetallic strip, bends or straightens, so that the first free part 54 exerts a greater or lesser force on the protrusion, and therefore on the first moving element 12, which moves while being guided by the first translation table. Thus, via the first flexible blade 11, the elastic element 5 receives a force or a torque modifying its stiffness and therefore the operation of the regulating organ 1.

[0041] Adjustment means, such as a screw, can be added to exert a force 57 on the second moving element 18, particularly at the end of the second arm 58, parallel to the longitudinal axis of the bimetallic strip. This allows the effective length d of the bimetallic strip to be adjusted, thereby controlling the effect of the preload means 6 on the elastic element 5, especially as a function of temperature. By moving the second moving element 18, guided by the second translation table, the contact between the free portion 54 and the protrusion 53 is modified, thus increasing or decreasing the effective length d of the bimetallic strip. Consequently, the greater the effective length, the more the force exerted on the first moving element 12 varies with temperature.

[0042] In the event of curved deformation of the deformable body 15, the free part 54 pushes the first moving element 12, so that the first flexible blade 11 transmits a force or torque to the suspended point mass 3. Thus, the stiffness of the pair of uncrossed blades 4 decreases. Conversely, if the deformable body 15 straightens, the force or torque on the suspended point mass 3 decreases, so that the stiffness of the pair of uncrossed blades 4 increases.

[0043] In the second embodiment, the regulating member 10 comprises a spiral spring, an oscillating mass (not shown in the figure), an elastic element 5, and a first flexible blade 11 identical to the first embodiment.

[0044] To exert force or torque on the elastic element 5, the spring portion of the prestressing means 6 comprises a first elongated movable element 22, connected to the flexible blade 11 and arranged in its extension. A first pair of parallel flexible blades 24 connects the first movable element 22 to a second fixed support 23 to form a translation table and guide the movement of the first movable element 22.

[0045] The spring part includes a second pair of parallel flexible blades 25 arranged on the same side as the first pair of parallel flexible blades 24, and connects the first moving element 22 to a second moving element 28.

[0046] The second moving element 28 is laterally connected to the deformable body 15 thermally by a second flexible blade 21 substantially parallel to the first moving element 22 in the rest position of the regulating organ 10.

[0047] In this embodiment, the deformable body is preferably also a bimetallic strip arranged perpendicularly to the second flexible strip 21 and the first movable element 22. The second flexible strip 21 is connected to the top of the free part of the bimetallic strip, the latter being held by a fixed support at its base.

[0048] Thus, when the bimetallic strip bends or straightens, the second flexible strip 21 transmits a displacement to the second moving element 28, which transmits it to the first moving element 22 via the second pair of parallel flexible strips 25. The first moving element 22 is guided by the first translation table to transmit the force or torque to the elastic element 5 through the first flexible strip 11.

[0049] Similar to the first embodiment, the temperature variation will cause a deformation of the thermally deformable body 15, and a change in the stiffness of the elastic element 5, and therefore in the operation of the regulating organ 10.

[0050] A third pair of parallel flexible blades 26 connects the second moving element 28 to a third moving element 27. The third pair of parallel flexible blades 26 and the third moving element 27 are arranged in series with the second pair of parallel flexible blades 25 and the second moving element 28.

[0051] Adjustment means, such as a screw, can be added to exert a force 59 on the third moving element 27. By increasing the force 59, the displacement of the bimetallic strip is transmitted less strongly to the first moving element 22, while by decreasing the force, the displacement of the bimetallic strip is transmitted more strongly to the first moving element 22. The adjustment means allow the sensitivity of the preload means 6 to be adjusted according to the temperature.

[0052] The invention also relates to a clockwork movement, not shown in the figures, the movement comprising a rotating regulating organ 1, 10 as described above.

[0053] Naturally, the invention is not limited to the embodiments described with reference to the figures and variants could be envisaged without departing from the scope of the invention.

Claims

1. Regulating member (1, 10) for a horological movement comprising an oscillating weight, for example a balance, and a balance spring comprising a flexible strip (2) wound about itself in a plurality of turns, the strip (2) having a predefined rigidity to allow the oscillating weight to undergo a rotary oscillatory motion, the strip (2) comprising an outer end (9), characterised in that the regulating member (1, 10) comprises a temperature-compensating resilient device configured to adapt the stiffness thereof as a function of the temperature to compensate for the effect of temperature on the regulating member (1, 10), the resilient device comprising a resilient element (5) connecting the outer end (9) to a first support (7) that is stationary relative to the horological movement, as well as preloading means (6) for applying a variable force or torque to the resilient element (5) as a function of the temperature.

2. Regulating member according to claim 1, characterised in that the preloading means (6) comprise a spring part connected to the resilient element (5), the spring part transmitting the force or torque to the resilient element (5).

3. Regulating member according to claim 2, characterised in that the preloading means (6) comprise a body (15) that can deform as a function of temperature, the deformable body (15) being at least partially in contact with the spring part during the deformation.

4. Regulating member according to claim 3, characterised in that the deformable body (15) is an elongate bimetallic attachment.

5. Regulating member according to claim 2 and any one of the preceding claims, characterised in that the spring part comprises a first flexible blade (11) connected to the resilient element (5).

6. Regulating member according to claim 5 and any one of claims 3 to 4, characterised in that the spring part comprises a translation stage connected to the first flexible blade (11), the deformable body being in contact with the translation stage.

7. Regulating member according to claims 3 and 5 and any one of claims 3 to 4, characterised in that the spring part comprises a second flexible blade (21) connected to the thermally deformable body.

8. Regulating member according to any one of the preceding claims, characterised in that the regulating member (1, 10) extends substantially in one and the same plane.

9. Regulating member according to any one of the preceding claims, characterised in that the resilient element (5) comprises a suspended point-shaped body (3) and a pair of non-crossing blades (4) connecting the suspended point-shaped body (3) to the first stationary support (7).

10. Regulating member according to claim 9, characterised in that the preloading means (6) are connected to the suspended point-shaped body (3) so as to exert the force or torque on the suspended point-shaped body (3).

11. Regulating member according to any one of the preceding claims, characterised in that it comprises means for regulating the preloading means (6) so as to apply a variable force (59) to the preloading means (6), for example to a first movable element (22).

12. Horological movement comprising a regulating member (1, 10) according to any one of the preceding claims.