CH719913A2 - Clockwork regulating organ with spiral spring provided with means of temperature compensation. - Google Patents

Abstract

The invention relates to a regulating member (1) for a watch movement comprising an oscillating mass, for example a balance wheel, a spiral spring comprising a flexible ribbon (2) wound on itself in several turns, the ribbon (2) having a predefined rigidity to allow the oscillating mass to perform a rotary oscillatory movement, the ribbon (2) comprising an external end (9), characterized in that the regulating member (1) comprises an elastic device for compensating the temperature configured to adapt its stiffness as a function of the temperature in order to compensate for the effect of the temperature on the regulating member (1), the elastic device comprising an elastic element (5) connecting the external end (9) to a first immobile support (7) relative to the clockwork movement, as well as prestressing means (6) for applying a variable force or torque on the elastic element (5) as a function of the temperature. The invention also relates to a watch movement comprising such a regulating member (1).

Description

Technical field of the invention

[0001] The invention relates to a spiral spring regulating member provided with temperature compensation means, particularly for watchmaking.

Technology background

[0002] Most current mechanical watches are equipped with a sprung balance and a Swiss anchor escapement mechanism. The sprung balance constitutes the time base of the watch. It is also called a resonator or regulating organ.

[0003] The exhaust, for its part, fulfills two main functions: – maintain the comings and goings of the resonator; – count these comings and goings.

[0004] To constitute a mechanical resonator, you need an inertial element, guidance and an elastic return element. Traditionally, a spiral spring plays the role of an elastic return element for the inertial element that constitutes a balance wheel. This balance wheel is guided in rotation by pivots, which generally rotate in plain ruby bearings.

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

However, during its operation, such a mechanical resonator may be subject to disturbances caused by changes in external parameters, which generate variations in frequency of the resonator. These parameters are for example temperature, pressure, humidity, or gravity. The variation in frequency of the resonator results in an error in the measurement of time and therefore in the running of the clock movement.

[0007] Document CH 704687 describes a regulating member comprising a spiral spring and a member for correcting the position of the pin to correct deformations of the spiral spring due to certain parameters, in particular temperature.

[0008] However, such a correction member does not achieve a desired level of precision.

Summary of the invention

[0009] The aim of the present invention is to overcome all or part of the drawbacks mentioned above by proposing a watchmaking regulating body with a spiral spring provided with more precise temperature compensation means.

[0010] For this purpose, the invention relates to a rotary regulating member for a timepiece movement comprising an oscillating mass, for example a balance wheel, a spiral 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 member comprises an elastic temperature compensation device configured to adapt its stiffness as a function of the temperature in order to compensate for the effect of the temperature on the regulating member, the elastic device comprising an elastic element connecting the external end to a first support stationary relative to the clockwork movement, as well as prestressing means for applying a variable force or torque on the elastic element as a function of the temperature.

[0012] Thanks to the invention, the prestressing means exert a variable force or torque on the elastic element as a function of the temperature, so that the regulating member substantially maintains a precise course despite significant changes in the temperature . Indeed, when the temperature changes, the prestressing means modify the force or the torque exerted on the elastic element, so that the stiffness of the assembly comprising the elastic element and the spiral spring is modified. By modifying the stiffness of this assembly, we adjust the operation of the regulating organ. Consequently, when the temperature changes, the elastic device is mechanically impacted to adjust the action of the spiral spring to this change.

[0013] This elastic element modifies the rigidity of the attachment point and provides additional flexibility to the resonator. Thus, the effective stiffness of the resonator includes 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 tape and without moving the end of the tape. By pre-stressing the elastic element, its rigidity changes, while the rigidity of the ribbon remains unchanged, since it is not pre-stressed and its end does not move.

By changing the flexibility of the elastic element, the rigidity of the resonator (rigidity of the ribbon and rigidity of the elastic element) changes, which consequently modifies the operation of the resonator. The elastic element being preferably more rigid than the ribbon, the share of the rigidity of the elastic element in the overall rigidity is less than that of the ribbon. Consequently, a modification of the rigidity of the elastic element modifies the rigidity of the entire resonator, and consequently fine-tunes its operation, which makes it possible to precisely adjust the frequency of our time base. We thus obtain great precision in maintaining operation 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 the torque to the elastic element.

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

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 member extends substantially in the same plane.

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 immobile 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 the torque on the suspended point body.

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

The invention also relates to a watch movement comprising such a regulating member.

Brief description of the figures

[0026] The aims, advantages and characteristics of the present invention will appear on reading several embodiments given solely by way of non-limiting examples, with reference to the appended drawings in which: – Figure 1 schematically represents a top view of a regulating member according to a first embodiment of the invention, and – Figure 2 schematically represents a top view of a regulating member according to a second embodiment of the invention.

Detailed description of the invention

Figures 1 and 2 represent two embodiments of a regulating member according to the invention.

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

The regulating member 1, 10 comprises an oscillating mass, for example an annular balance, not shown in the figures, which is connected to the internal end 8 of the ribbon 2, the ribbon 2 having a predefined rigidity to allow the oscillating mass to perform a rotary oscillatory movement. For example, the oscillating mass comprises an axial rotation shaft, the internal end 8 of the ribbon 2 being connected to said shaft.

Preferably, the regulating member 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 the temperature in order to compensate for the effect of the temperature on the regulating organ 1, 10.

The elastic device 50 comprises an elastic element 5 connecting the external end 9 to a stationary support 7 relative to the clock movement, for example to a plate. The elastic device 50 further comprises prestressing means 6 for applying a variable force or torque to the elastic element 5 as a function of 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 immobile support 7. The suspended point body 3 is for example a cylindrical body of height substantially equal to the diameter , the uncrossed blades 4 moving away from the suspended point body 3 to the immobile support 7.

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.

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 portion provided with a flexible blade 11 connected to the suspended point body 3. The first blade flexible 11 extends in the axis of the elastic element, tangentially to the spiral spring, and is slightly offset relative to the external end 9.

[0036] In the first embodiment of Figure 1, the spring part of the prestressing means 6 comprises a translation table provided with a first movable element 12 in the shape of an L and a second stationary 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 includes a rounded projection 53 on the external side. The translation table comprises two substantially parallel flexible blades 14 connecting the first movable element 12 to the second stationary support 13.

The prestressing means 6 further comprise a thermally deformable body 15 as a function of the temperature, the deformable body 15 exerting the variable force or torque on the movable element 12.

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

The bimetallic strip is arranged perpendicular to the movable element 12, so that a first free part 54 is in contact with the protrusion 53 of the second arm of the L. The retained end 55 is held by a second table of translation comprising a second movable element 18 and a second pair 17 of parallel flexible blades connecting the second movable element 18 to a third immobile support 19 relative to the movement plate. The second movable element 18 has an L shape, one arm of the L supporting the retained end 55 of the bimetallic strip, while the blades of the second pair 17 of blades connect the internal face 56 of the second arm to the third immobile support 19. The blades of the second pair 17 of blades are arranged perpendicular to the bimetallic strip in the rest position of the prestressing means 6.

[0040] In the event of a change in temperature, the deformable body 15, here the bimetallic strip, bends or straightens, so that the first free part 54 exerts a more or less significant force on the protrusion, and therefore on the first movable 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 member 1.

[0041] Adjustment means, such as a screw, can be added to exert a force 57 on the second movable element 18, in particular at the end of the second arm 58, parallel to the longitudinal axis of the bimetallic strip. Thus, we can adjust the effective length d of the bimetallic strip, to adjust the effect of the prestressing means 6 on the elastic element 5, in particular as a function of the temperature. By moving the second movable element 18, guided by the second translation table, the contact between the free part 54 and the projection 53 is modified, and thus the effective length d of the bimetallic strip is increased or reduced. Thus, the greater the effective length, the more the force exerted on the first movable element 12 varies as a function of the temperature.

[0042] In the event of curved deformation of the deformable body 15, the free part 54 pushes the first movable element 12, so that the first flexible blade 11 transmits a force or a torque on the suspended point body 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 body 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.

To exert the 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 immobile support 23 to form a translation table and guide the movement of the first movable element 22.

The spring part comprises 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 movable element 22 to a second movable element 28.

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

[0047] In this embodiment, the deformable body is preferably also a bimetallic strip arranged perpendicularly to the second flexible blade 21 and to the first movable element 22. The second flexible blade 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 curves or straightens, the second flexible blade 21 transmits a movement to the second movable element 28, which transmits it to the first movable element 22 by the second pair of parallel flexible blades 25. The first movable element 22 is guided by the first translation table to transmit the force or torque to the elastic element 5 through the first flexible blade 11.

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

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

[0051] Adjustment means, such as a screw, can be added to exert a force 59 on the third movable element 27. By increasing the force 59, the movement of the bimetallic strip is transmitted more weakly to the first movable element 22, while by reducing the force, the movement of the bimetallic strip is transmitted more strongly to the first movable element 22. The adjustment means make it possible to adjust the sensitivity of the prestressing means 6 as a function of the temperature.

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

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

Claims (12)

1. Regulating member (1, 10) for a watch movement comprising an oscillating mass, for example a balance wheel, a spiral spring comprising a flexible ribbon (2) wound on itself in several turns, the ribbon (2) having a predefined rigidity to allow the oscillating mass to perform a rotary oscillatory movement, the ribbon (2) comprising an external end (9), characterized in that the regulating member (1, 10) comprises an elastic device for compensating for the temperature configured to adapt its stiffness as a function of the temperature in order to compensate for the effect of the temperature on the regulating member (1, 10), the elastic device comprising an elastic element (5) connecting the external end (9) to a first immobile support (7) relative to the clockwork movement, as well as prestressing means (6) for applying a variable force or torque to the elastic element (5) as a function of the temperature. 2. Regulating member according to claim 1, characterized in that the preloading means (6) comprise a spring part connected to the elastic element (5), the spring part transmitting the force or the torque to the elastic element (5 ). 3. Regulating member according to claim 1 or 2, characterized in that the prestressing means (6) comprise a deformable body (15) as a function of the temperature, the deformable body (15) being at least partly in contact with the part springs during deformation. 4. Regulating member according to claim 3, characterized in that the deformable body (15) is an elongated bimetallic strip. 5. Regulating member according to any one of the preceding claims, characterized in that the spring part comprises a first flexible blade (11) connected to the elastic element (5). 6. Regulating member according to claim 5 and any one of claims 3 and 4, characterized in that the spring part comprises a translation table connected to the first flexible blade (11), the deformable body being in contact with the translation table. 7. Regulating member according to claim 5 and any one of claims 3 and 4, characterized 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, characterized in that the regulating member (1, 10) extends substantially in the same plane. 9. Regulating member according to any one of the preceding claims, characterized in that the elastic element (5) comprises a suspended point body (3) and a pair of uncrossed blades (4) connecting the suspended point body (3). ) to the first immobile support (7). 10. Regulating member according to claim 9, characterized in that the prestressing means (6) are connected to the suspended point body (3) to exert the force or torque on the suspended point body (3). 11. Regulating member according to any one of the preceding claims, characterized in that it comprises means for adjusting the prestressing means (6), to apply a variable force (59) on the prestressing means (6) , for example on the first mobile element (22). 12. Clock movement comprising a regulating member (1, 10), according to any one of the preceding claims.