Spiral spring for a horological resonator mechanism provided with means for adjusting the stiffness
A spiral spring for a horological resonator mechanism, including a flexible strip ( 2 ) coiled on itself into several turns, the strip ( 2 ) having a predefined stiffness. The spring ( 1 ) include an element for adjusting its stiffness, including a unique elongate flexible element ( 5 ) arranged in series with the strip ( 2 ), and connecting one end ( 4 ) of said strip ( 2 ) to a fixed support ( 11 ), to add additional stiffness. The flexible element ( 5 ) has a stiffness higher than that of the strip ( 2 ). A prestressing element ( 6 ) applies two different efforts on the element ( 5 ), and includes a first lever ( 8 ) attached to the end ( 4 ) of the strip ( 2 ) to allow adjusting a first effort, and a second lever ( 8 ) also attached to the end ( 4 ) of the strip ( 2 ) to adjust a second effort independently of the first effort.
1 . A spiral spring for a horological resonator mechanism, the spiral spring comprising:
a flexible strip coiled on itself into several turns, the strip having a predefined stiffness; and
means for adjusting stiffness of the spiral spring, the adjustment means including a elongate flexible element arranged in series with the strip, the elongate flexible element connecting one end of said strip to a fixed support, the elongate flexible element having a stiffness higher than that of the strip, the adjustment means including prestressing means to apply at least two different efforts on the elongate flexible element,
wherein the prestressing means include a first lever attached to the end of the strip so as to allow adjusting a first effort, and a second lever also attached to the end of the strip so as to adjust a second effort independently of the first effort.
2 . The spiral spring according to claim 1 , wherein the first effort is imparted, either by a first tensile/compressive force directed substantially in the longitudinal direction of the elongate flexible element, or by a first force directed substantially in a direction substantially orthogonal to the longitudinal direction of the elongate flexible element, or by a first torque or a bending moment, so as to make the stiffness of the elongate flexible element vary according to the prestress level.
3 . The spiral spring according to claim 1 , wherein the second effort is imparted either by a second tensile/compressive force directed substantially in the longitudinal direction of the elongate flexible element, or by a second force directed substantially in a direction substantially orthogonal to the longitudinal direction of the elongate flexible element, or by a second torque or a bending moment, so as to make the stiffness of the elongate flexible element vary according to the prestress level.
4 . The spiral spring according to claim 1 , wherein the prestressing means are configured to exert a third effort on the elongate flexible element, the third effort being imparted, respectively at the first effort, either by the first tensile/compressive force, or by the substantially orthogonal first force, or by the first torque.
5 . The spiral spring according to claim 4 , wherein the third effort is adjustable by the first lever.
6 . The spiral spring according to claim 4 , wherein the prestressing means are configured to exert a fourth effort on the elongate flexible element, the fourth effort being imparted, respectively at the second effort, either by the second tensile/compressive force, or by the substantially orthogonal second force, or by the second torque.
7 . The spiral spring according to claim 6 , wherein the fourth effort is adjustable by the second lever.
8 . The spiral spring according to claim 6 , wherein the prestressing means are configured to exert a fifth effort on the elongate flexible element, the fifth effort being imparted, respectively at the first effort and at the third effort, either by the first tensile/compressive force, or by the substantially orthogonal first force, or by the first torque.
9 . The spiral spring according to claim 8 , wherein the fifth effort is adjustable by the first lever.
10 . The spiral spring according to claim 8 , wherein the prestressing means are configured to exert a sixth effort on the elongate flexible element, the sixth effort being imparted, respectively to the second effort and at the fourth effort, either by the second tensile/compressive force, or by the substantially orthogonal second force, or by the second torque.
11 . The spiral spring according to claim 10 , wherein the sixth effort is adjustable by the second lever.
12 . The spiral spring according to claim 1 , wherein the elongate flexible element is a flexible blade.
13 . The spiral spring according to claim 1 , wherein the flexible element is arranged in a radial direction of the spiral spring.
14 . The spiral spring according to claim 1 , wherein the first and second levers are flexible.
15 . The spiral spring according to claim 1 , wherein the first lever comprises a first free end which can be actuated by a movement of said first free end in order to apply said efforts on the elongate flexible element, and the second lever comprises a second free end which can be actuated by a movement of said second free end in order to apply said efforts on the elongate flexible element.
16 . The spiral spring according to claim 1 , wherein the first and second levers are configured to enable an adjustment of the effort(s) at different intensities.
17 . The spiral spring according to claim 16 , wherein the first and second levers have a section or a stiffness different from one another.
18 . The spiral spring according to claim 1 , wherein the effort(s) is/are continuously adjustable by the prestressing means.
19 . The spiral spring according to claim 1 , wherein the flexible element and the levers are arranged at an outer end of the strip.
20 . A rotary resonator mechanism for a horological movement, including an oscillating mass, wherein the resonator mechanism includes the spiral spring according to claim 1 .