CH713780B1 - Movement and timepiece comprising two balance-springs of different frequencies. - Google Patents

Abstract

Disclosed are a movement and a timepiece capable of ensuring high precision in time measurement and achieving energy saving and elimination of wear of each gear element. The movement comprises: a first balance-spring (73) which performs an alternating rotational movement; a second balance-spring (87) which performs an alternating rotational movement at a frequency different from that of the first balance-spring (73); a seconds wheel (130) on which a seconds hand (6) is mounted; and an energy transmission mechanism (26) adapted to switch between a mode at the higher frequency in which the energy delivered at the output of the movement barrel (24) is transmitted to the first balance-spring (73), and a mode at the lower frequency in which the energy delivered at the output of the movement barrel (24) is transmitted to the second balance-spring (87), and modifying the power delivered at the output of the movement barrel (24) with the speed of rotation of this movement barrel (24) between the higher frequency mode and the lower frequency mode to rotate the seconds wheel (130) at a fixed rotational speed, which is identical between the first state and the second state.

Description

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

The present invention relates to a movement and a timepiece.

PRIOR ART

[0002]As a movement of a mechanical timepiece, architectures comprising a plurality of regulators are known. For example, Japanese Patent No. 4499681 discloses an architecture in which the energy of a movement barrel is distributed to each regulator by a differential mechanism, through which the frequency of each regulator is averaged. According to Japanese Patent No. 4499681, a gear train is driven based on the average speed of each regulator, whereby an improvement in timing accuracy can be realized.

[0003] In the architecture disclosed in Japanese Patent No. 4499681, however, a plurality of regulators operate simultaneously, so that a lot of energy is used by the barrel of the movement. Therefore, attempting to maintain the timepiece's operating life at high levels (i.e. maintaining a long operating life of the mainspring, also commonly referred to as the power reserve), leads to an increase in the size of the movement barrel (housing the mainspring of the barrel supplying the movement with energy).

[0004] In addition, in the regulator, the higher the frequency of the regulating members, the smaller the influence of the disturbances (generated by external forces), and thus the higher the accuracy of the time measurement. However, on the other hand, in the regulator, the higher the frequency, the greater the amount of energy used by the barrel of the movement, and therefore the faster the wear of each tooth of the gear elements.

SUMMARY OF THE INVENTION

[0005] According to the present patent application, the aim is to provide a movement and a timepiece which help to ensure high precision in the measurement of time and which can achieve energy savings, as well as a suppression wear of the gear teeth.

To obtain the above advantages, a movement according to one mode of the present patent application is according to claim 1.

According to this present embodiment, the switching between the first state and the second state is carried out via the energy transmission mechanism, thanks to which, compared to a configuration according to which the first balance-spring and the second balance- hairspring are actuated simultaneously by the movement barrel, it is possible to reduce energy consumption at the level of the movement barrel (it is possible to achieve energy savings). It is thus possible to avoid any increase in size of the movement barrel while maintaining the operating time of the timepiece at the same level.

[0008] In particular, in the present embodiment, thanks to the energy transmission mechanism, the energy of the movement barrel is adjusted in terms of speed depending on whether one is in the first state or the second state. to rotate the indicator needle wheel at a fixed rotational speed, so that it is possible to switch between the first state and the second state according to the situation. In this case, for example, in a state where the timepiece is worn and in a situation in this state where disturbances can relatively easily affect the timepiece (for example, during the practice of a sport), a kinematic connection to the balance-spring at the higher frequency is achieved, thereby eliminating the influence of disturbances. Therefore, it is possible to realize an improvement in the accuracy of time measurement. On the other hand, in the unworn state of the timepiece, and in a situation in a worn state in which the timepiece is relatively little exposed to disturbances, etc., a kinematic connection to the balance- hairspring at the lower frequency is achieved, thanks to which it is possible to achieve energy savings for the movement barrel, which makes it possible to increase the operating time of the timepiece (the duration of the mainspring of the barrel, i.e. the power reserve). Further, it is possible to suppress the wear of each gear element.

In the embodiment mentioned above, the energy transmission mechanism can be equipped with a first transmission mechanism connected to the first balance-spring and the second balance-spring; the first transmission mechanism may have three gear elements formed by a first sun wheel, a second sun wheel arranged coaxially with the first sun wheel, and a planet carrier rotatably mounted coaxial with the first sun wheel and bearing a rotary planet gear meshing with the first sun gear and the second sun gear; among the three gear elements mentioned above, a first gear element is able to transmit energy to the first balance-spring in the first state, a second gear element is able to transmit energy to the second balance-spring in the second state, and a third gear element is capable of receiving energy from the movement barrel.

According to the present embodiment, a planetary mechanism is adopted as the first transmission mechanism, by which it is possible to easily perform switching between the first state and the second state. In other words, in the first state, the rotation of the second gear element is stopped, the energy transmitted to the third gear element being transmitted to the first gear element via the planet gear, and then transmitted to the gear wheel. indicator needle. On the other hand, in the second state, it is the rotation of the first gear element which is stopped, the energy transmitted to the third gear element being transmitted to the second gear element via the planet wheel, and then transmitted to the indicator needle wheel.

In the above embodiment, the movement can be according to claim 3.

[0012] According to the present embodiment, by adjusting the number of teeth of the planet wheel, it is possible to make the rotational speeds of the first gear element and the second gear element different from each other. other. Consequently, it is possible to cancel the frequency difference between the first balance-spring and the second balance-spring via the first transmission mechanism. Thus, regardless of whether one is in the first state or the second state, it is possible to operate the indicator pointer wheel at a fixed rotational speed.

In the above embodiment, the energy transmission mechanism may comprise a first transmission mechanism kinematically connected to the first balance-spring and the second balance-spring, and the first transmission mechanism may comprise a first gear element kinematically connected to the first balance-spring, a second gear element arranged coaxially with respect to the first gear element and kinematically connected to the second balance-spring, a third gear element arranged coaxially with relative to the first gear element and to the second gear element, and kinematically connected to the movement barrel, and a clutch part capable of making the first gear element integral in rotation with the third gear element in the first state, and the second gear element integral in rotation with the third gear element in the second state.

In the present embodiment, a clutch mechanism is adopted as the first transmission mechanism, by which it is possible to easily switch between the first state and the second state.

[0015] In the above embodiment, the movement can be according to claim 5.

[0016] According to the present embodiment, by adjusting the number of teeth of the first gear element and the second gear element, it is possible to make the rotation speeds of the first gear element and the second gear element d gears different from each other. Consequently, it is possible to eliminate the frequency difference between the first balance-spring and the second balance-spring by means of the first transmission mechanism. Therefore, regardless of whether the timepiece is in the first state or in the second state, it is possible to operate the indicator hand wheel at a fixed rotational speed.

[0017] In the above embodiment, the power transmission mechanism may be equipped with a second transmission mechanism transmitting power from the first gear element or the second gear element to the power wheel. indicator needle.

According to the present embodiment, it is possible to effectively transmit power from the first gear member or the second gear member to the indicator needle wheel.

In the above embodiment, the energy transmission mechanism can be equipped with a regulation mechanism which immobilizes the second balance-spring in the first state and which immobilizes the first balance-spring in the second state.

[0020] According to the present embodiment, in the first state and the second state, the reciprocating rotational movement of the balance-spring which does not contribute to the hand movement is stopped, whereby it is possible to maintain the balance-spring of the balance-spring not contributing to the hand movement in its extended/contracted state (it is possible to prevent it from reaching its nominal length at rest). Thus, after switching between the first state and the second state, it is possible to allow the balance-spring to quickly return to a normal operating state.

In the above embodiment, the movement can be according to claim 8.

[0022] In this case, the movement barrel is kinematically connected to the balance-spring at the lower frequency via the energy transmission mechanism, thanks to which it is possible to save energy for the movement barrel and to achieve an increase in the operating time of the timepiece (the life of the mainspring, that is to say the power reserve).

A timepiece according to one embodiment for the present invention can be equipped with a movement according to the above embodiment.

According to this embodiment, it is possible to provide a superior timepiece in terms of quality and reliability.

[0025] According to the present patent application, it is possible to eliminate the wear of each of the teeth of the various gear elements used and to achieve energy savings while guaranteeing the precision necessary for measuring time.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is an external view of a timepiece according to a first embodiment. Figure 2 is a plan view, seen from the bottom, of the main part of a movement according to the first embodiment. Figure 3 is a diagram illustrating the movement according to the first embodiment. Figure 4 is a perspective view of the main part of the movement according to the first embodiment. Figure 5 is an exploded perspective view of a first differential mechanism. Figure 6 is a sectional view of the first differential mechanism. Figure 7 is an exploded perspective exploded view of a second differential mechanism. Figure 8 is a sectional view of the second differential mechanism. Fig. 9 is a plan view illustrating a mode at the lower frequency corresponding to Fig. 2. Fig. 10 is a diagram illustrating a movement according to a variant of the first embodiment. FIG. 11 is a diagram illustrating a movement according to a variant of the first embodiment. Figure 12 is a sectional view of a first differential mechanism in a movement according to a second embodiment. Fig. 13 is a sectional view to illustrate a higher frequency mode corresponding to Fig. 12. Fig. 14 is a sectional view of a second differential movement having another architecture according to this embodiment.

DETAILED DESCRIPTION OF THE INVENTION

In the following, embodiments of the present invention will be described with reference to the drawings.

First embodiment

timepiece

[0028] Figure 1 is an external view of a timepiece 1. In the following drawings, in order to facilitate understanding of the invention, certain components of the timepiece will deliberately not be represented and simplified. in some cases.

As shown in Figure 1, the timepiece 1 according to this embodiment is made by inserting a movement 2, a dial 3, various indicator hands 4 to 6, etc. in a box 7.

The case 7 of the timepiece is equipped with a middle part 11, a case cover (that is to say a bottom, not shown), and a protective glass (glass) 12. A Crown 15 is arranged at 3 o'clock (on the right side of FIG. 1) from the side surface of caseband 11. Crown 15 is used to actuate movement 2 from outside caseband 11 of the case. Crown 15 is fixed to a winding stem 19 inserted in middle 11.

Movement

[0031] In movement 2, a plurality of gear elements, etc. are rotatably mounted on a plate 21 constituting the base plate of the movement 2. The winding stem 19 mentioned above is inserted into the plate 21. The winding stem 19 is used when it is desired to correct the date and the hour. The winding stem 19 is rotatably mounted around its axis, and it is movable in the axial direction. In the following description, reference is made to the "rear side" of the movement 2 to designate the side of the protective glass 12 (that is to say the side of the dial 3) of the timepiece case 7 with respect to to the main plate 21, and the "front side" of the movement 2 is referred to as the side of the cover of the case (i.e. the side opposite that of the dial 3, which is usually referred to as the "bottom side"). The axial direction of each of the gears described below extends from the front to the rear of movement 2.

[0032] Figure 2 is a plan view from the rear (dial side) of the main part of the movement 2. Figure 3 is a diagram of the movement 2. The numbers in parentheses in Figure 3 indicate the ratio between the operating speed in the lower frequency mode relative to that of the higher frequency mode, in the event that the operating speed of the higher frequency mode described below is chosen by convention to be equal to 1.

As shown in Figures 2 and 3, a movement barrel 24, a center wheel set 25, a switching mechanism (power transmission mechanism) 26, a first escapement-regulator assembly 27, a second escapement assembly -regulator 28, a regulation mechanism (energy transmission mechanism) 29, a display train 30, etc. are mounted on plate 21 of movement 2 (see FIG. 1).

[0034] The movement barrel 24 contains a mainspring (that is to say the barrel spring, not shown) serving as a power supply source for the timepiece 1. The barrel spring is wound for its winding, for example, under the action of the rotation of the winding stem 19. The movement barrel 24 is rotated by the rotational force (return force) when the barrel spring is wound (rewound ).

A center pinion 25a of the center wheel set 25 meshes with the movement barrel 24. A center wheel 25b of the center wheel set 25 is connected to the switching mechanism 26.

Switch mechanism

[0036] Figure 4 is a perspective view of the main part of the movement 2.

As shown in Figure 4, the switching mechanism 26 is equipped with a first differential mechanism (first transmission mechanism) 42, a second differential mechanism (second transmission mechanism) 43, a second mobile 44 of a first kinematic chain, a second mobile 45 of a second kinematic chain, etc.

The first differential mechanism 42 transmits the energy transmitted from the movement barrel 24 via the center wheel set 25 either to the first of the second wheel sets 44 or to the second of the second wheel sets 45.

Figure 5 is an exploded perspective view of the first differential mechanism 42. Figure 6 is a sectional view of the first differential mechanism 42.

As shown in Figures 5 and 6, the first differential mechanism 42 has a first front sun wheel (first sun wheel constituting the third gear element) 51, a first planet carrier (constituting the first gear element ) 52, as well as a first planet wheel 53 and a first rear sun wheel (second sun wheel, constituting the second gear element) 54. The first differential mechanism 42, the first front sun wheel 51, the first planet carrier 52, and the first rear sun wheel 54 are arranged coaxially with each other, their axial direction extending from front to rear, and they are constituted in such a way as to allow relative rotation of each other. relation to others.

First, the first planet carrier 52 has a shaft 52a, and a body 52b fixed to the shaft 52a.

[0042] Shaft 52a extends through both first front sun gear 51 and first rear sun gear 54 in the front-to-rear direction.

The body of the planet carrier 52b is arranged between the first front sun wheel 51 and the first rear sun wheel 54 in the front-rear direction. The body of the planet carrier 52b has a hub 61 fixed to the shaft of the first planet carrier 52a, a rim 62 surmounting the hub 61, and arms 63 connecting the hub 61 to the rim 62.

On the outer peripheral surface of the rim 62 is formed a gear toothing 52c of the first planet carrier.

On the first front sun gear 51 are respectively arranged a first front sun gear 51b and a first front sun gear toothing 51c at both front and rear ends of a first front sun shaft 51a.

The first front solar shaft 51a has a tubular configuration. The front end (bottom side) of the first planet carrier shaft 52a is inserted into the first front sunshaft 51a via a bearing 64. Accordingly, the first front sun gear 51 is rotatably mounted with respect to the first carrier. satellite 52.

The first front sun gear 51b is located at the front end (bottom side) of the first front sun shaft 51a. The first front sun gear 51b meshes with the center wheel 25b of the center mobile 25.

In the first rear sun gear 54 are respectively arranged a first rear sun gear 54b and a first rear sun gear toothing 54c at both front and rear ends of a first rear sun shaft 54a.

The first rear solar shaft 54a has a tubular configuration. The rear end (dial side) of the first planet carrier shaft 52a is inserted into the first rear sunshaft 54a via a bearing 65. Accordingly, the first rear sun gear 54 is rotatably mounted with respect to the first carrier. satellite 52.

The first satellite wheel 53 is rotatably mounted on an arm 63a selected from all the arms (radial parts) 63 of the first planet carrier mentioned above 52 (that is to say the body of the planet carrier 52b). In the first planet gear 53 are respectively arranged a first planet pinion 53b and a first planet gear toothing 53c at both front and rear ends of a first planet shaft 53a.

The first satellite shaft 53a extends through an arm 63a in the front-rear direction. The first satellite shaft 53a is rotatably mounted on an arm 63a via a bearing 66.

The first planet gear 53b is arranged at the front end (the part located on the bottom side with respect to the body of the planet carrier 52b) of the first planet shaft 53a. The first planet gear 53b meshes with the first front sun gear toothing 51c mentioned above.

The first satellite gear toothing 53c is arranged at the rear end (the part located on the dial side with respect to the body of the planet carrier 52b) of the first satellite shaft 53a. The first satellite gear tooth 53c meshes with the first rear sun gear 54b mentioned above. Thus, the first planet wheel 53 of the present embodiment performs complete revolutions around the first sunshafts 51a and 54a during the rotation of the first planet carrier 52, and rotates relative to the first planet carrier 52 via the rotation of the sun wheels 51 and 54.

Here, according to this embodiment, the number of teeth of the first differential mechanism 42 is defined as shown in Table 1.

Table 1

[0055] First rear sun gear 20 First front sun gear teeth 30 First satellite gear teeth 20 First satellite gear teeth 10

[0056] In this case, as shown in Table 2, when the first planet carrier 52 is stationary, the transmission gear ratio (speed increase rate) between the first rear sun wheel 54 and the first front sun gear 51 is "3." On the other hand, when the first rear sun gear 54 is stationary, the transmission gear ratio (speed increase rate) between the first planet carrier 52 and the first front sun wheel 51 is "1.5". the first planet carrier 52 and the first front sun wheel 51 when the first rear sun wheel 54 is stationary.

Table 2

[0057] First front sun wheel First planet carrier 3 1 0 First front sun wheel First rear sun wheel 0 1 1.5

As illustrated in Figure 4, a first second pinion 44a of the first of the second mobiles 44 meshes with the gear teeth of the first planet carrier 52c mentioned above. A first second wheel 44b of the first of the second mobiles 44 is kinematically connected to the first escapement-regulator assembly 27.

A second second pinion 45a of the second of the second mobiles 45 meshes with the first rear sun gear toothing 54c mentioned above. A second second wheel 45b of the second of the second mobiles 45 is kinematically connected to the second exhaust-regulator assembly 28. In the present embodiment, the second pinions 44a and 45a of the second mobiles 44 and 45, and its second wheels 44b and 45b have the same number of teeth.

As illustrated in Figures 2 and 4, the first escapement-regulator assembly 27 comprises a first escapement wheel set 71, a first lever 72, and a first balance-spring 73.

The first escape wheel set 71 has a first escape wheel 71a and a first escape pinion 71b. The first escapement pinion 71b meshes with the first second wheel 44b mentioned above of the first of the second mobiles 44. Thus, the first escapement mobile 71 is driven in rotation following that of the first second mobile 44.

The first anchor 72 is capable of performing alternate pivoting and reverse pivoting, its axial direction extending from front to rear. The first anchor 72 is fitted with a pair of paddles 74a and 74b. In response to the pivotings of the first lever 72 taking place alternately in one direction and in the opposite direction, the pallets 74a and 74b are alternately brought into engagement with the first escapement wheel 71a of the first escapement wheel set 71. When one pallet of the pair of pallets 74a and 74b is in engagement with the first escapement wheel 71a, the first escapement mobile 71 temporarily stops its rotation. When the pair of pallets 74a and 74b is disengaged from the first escapement wheel 71a, the first escapement mobile 71 rotates. These operations are repeated successively, which causes the first escapement wheel set 71 to rotate intermittently. And through the intermittent rotation of the first escape wheel set 71, the switching mechanism 26 mentioned above also operates intermittently.

The first balance-spring 73 regulates the speed of the first escapement wheel set 71 (that is, causes the first escapement wheel set 71 to rotate at a fixed speed). The first balance-spring 73 mainly has a first balance shaft 81, a first balance wheel 82, and a first hairspring 83.

[0064] The first balance shaft 81 performs rotary movements in the normal direction and the opposite direction at a fixed frequency determined by the energy transmitted by the first hairspring 83, the axial direction of which extends from the front to the 'back. In synchronization with the alternating rotational movement of the first balance-spring 73, the first balance shaft 81 repeats a movement of engagement with the pallet carrier (not shown) of the first anchor 72 followed by a disengagement of the latter . Consequently, the first anchor 72 performs alternately a pivoting and the reverse pivoting, through which the pallets 74a and 74b repeat a movement of engagement with the escapement wheel set 71 and of disengagement with respect to the latter.

[0065] The first balance wheel 82 is fixed to the first balance shaft 81 by driving in or the like.

The first spiral 83 is a flat spiral spring configured in the shape of a spiral, as can be seen in the plan view in the front-rear direction. The inner end of the first hairspring 83 is connected to the first balance shaft 81, and its outer end is connected to a peak (not shown).

The second escapement-regulator assembly 28 has a second escapement wheel set 85, a second lever 86, and a second balance-spring 87. The second escapement-regulator assembly 28 is configured according to an architecture equivalent to that of the first assembly. escapement-regulator 27, so that the description of some of its parts will not be systematically repeated as needed.

The second escape wheel set 85 has a second escape wheel 85a and a second escape pinion 85b. The second escapement pinion 85a meshes with the second wheel 45b of the second mobile 45 mentioned above. In other words, the second escapement wheel set 85 is driven in rotation following that of the second second wheel set 45. The number of teeth of the second escapement pinion 85b is configured as being equal to twice that of the first escapement pinion 71b of the first escape wheel set 71.

The second anchor 86 is equipped with a pair of pallets 91a and 91b. In response to the pivotings of the second lever 86 taking place alternately in one direction and in the opposite direction, the pallets 91a and 91b alternately engage with the second escapement wheel 85a of the second escapement wheel set 85, and rotate intermittently. And, through the intermittent rotational movement of the second escape wheel set 71, the switching mechanism 26 mentioned above also operates intermittently.

The second balance-spring 87 regulates the speed of the second escapement wheel set 85 (ie causes the second escapement wheel set 85 to rotate at a fixed speed). The second balance-spring 87 mainly has a second balance shaft 92, a second balance wheel 93, and a second hairspring 94.

Here, the frequency of the first balance-spring 73 and that of the second balance-spring 87 are different from each other. In the present embodiment, the frequency of the first balance-spring 73 is set at 4 Hz (8 oscillations per second). The frequency of the second balance-spring 87 is defined as being equal to half the frequency of the first balance-spring 73 (2 Hz, ie 4 oscillations per second). The frequency F of the balance-spring 73, 87 is expressed by the following equation (1), in which "I" represents the moment of inertia of the balance-spring, and "K" represents the spring constant of the balance-spring. F = 1/2π√K/I (1)

[0072] As seen in equation (1), the frequency F of the balance-spring 73, 87 varies in accordance with the moment of inertia "I" of the balance-spring 73, 87 and the spring constant "K “ of the hairspring 83, 94. More specifically, the smaller the moment of inertia “I”, the higher the frequency F, and the larger the spring constant K, the higher the frequency F. In the present embodiment, the moment of inertia "I" of the first balance-spring 73 (the outer diameter of the first balance wheel 82) is smaller than the moment of inertia "I" of the second balance-spring. 87 (the outer diameter of the second balance wheel 93), whereby the frequencies F of the sprung balances 73, 87 differ. The moment of inertia „I“ can be adjusted by changing the material, etc. of the balance wheel 82, 93. In addition, the frequency of the balance-spring 73 and that of the balance-spring 87 can be made different from each other by taking a spring constant "K" of the balance spring 83 different from that of balance spring 94. Furthermore, the frequency F of balance-spring 73 and that of balance-spring 87 can be changed as much as necessary as long as they remain different from each other.

[0073] Figure 7 is an exploded perspective view of the second differential mechanism 43. Figure 8 is a sectional view of the second differential mechanism 43.

As shown in Figures 7 and 8, the second differential mechanism 43 transmits the energy of the first differential mechanism 42 to the display train 30. More specifically, the second differential mechanism 43 has a second front sun wheel 101, a second planet carrier 102, a second planet wheel 103, and a second rear sun wheel 104. The second differential mechanism 43, the second front sun wheel 101, the second planet carrier 102, and the second rear sun wheel 104 are arranged in coaxially with each other, their axial direction extending from front to rear. At the same time, they can rotate relative to each other. In what follows, the description of the configuration elements which are identical to those of the first differential mechanism 42 will not be repeated in detail.

First, the second planet carrier 102 has a second shaft 102a, and a planet carrier body 102b fixed to the second shaft 102a.

The second shaft 102a extends respectively through the second front sun wheel 101 and the second rear sun wheel 104 from front to rear.

The body of the planet carrier 102b is arranged between the second front sun wheel 101 and the second rear sun wheel 104. The body of the planet carrier 102b has a hub 110 fixed to the second shaft 102a of the planet carrier, a serge 111 surmounting the hub 110, and a set of arms 112 connecting the hub 110 to the rim 111.

At the outer peripheral surface of the rim 111 is formed a second gear teeth 102c. The second gear toothing 102c meshes with the first gear toothing 52c of the first planet carrier 52 mentioned above.

In the second front sun gear 101, a second front sun gear 101b and a second front sun gear tooth 101 c are respectively arranged at both front and rear ends of a second front sun shaft. 101a.

The second front solar shaft 101a has a tubular configuration. The rear end (dial side) of the second shaft 102a of the second planet carrier mentioned above is inserted into the second front sunshaft 101a via a bearing 115.

In the second rear sun gear 104, a second rear sun gear 104b and a second rear sun gear tooth 104c are respectively arranged at both front and rear ends of a second rear sun shaft 104a.

[0082] The second rear solar shaft 104a has a tubular configuration. The rear end (dial side) of the second shaft 102a of the second planet carrier mentioned above is inserted into the second rear sunshaft 104a via a bearing 116.

The second rear sun gear tooth 104c meshes with the first rear sun gear tooth 54c mentioned above.

The second planet wheel 103 is rotatably mounted on an arm 112a chosen from all the arms (radial parts) 112 of the second planet carrier 102 (that is to say the body of the planet carrier 102b) mentioned upper. In the second planet wheel 103, a second planet pinion 103b and a second planet gear tooth 103c are arranged at both front and rear ends of a second planet shaft 103a.

[0085] The second satellite shaft 103a extends through an arm 112a in the fore-aft direction. The second satellite shaft 103a is rotatably mounted on an arm 112a via a bearing 117.

The second planet gear 103b is arranged at the front end of the second planet shaft 103a (the part located on the bottom side with respect to the body of the planet carrier 102b). The second satellite pinion 103b meshes with the second front sun gear 101b mentioned above.

The second satellite gear toothing 103c is arranged at the rear end of the second satellite shaft 103a (the part located on the dial side with respect to the body of the planet carrier 102b). The second satellite gear tooth 103c meshes with the second rear sun gear 104b mentioned above. Thus, second planet wheel 103 of this embodiment rotates around second sunshaft 101a, 104a in response to rotation of second carriage 102, and rotates relative to second carriage 102 when sunwheels 101 and 104 rotate.

Here, in this embodiment, the number of teeth of the second differential mechanism 43 is defined as shown in Table 3 below.

Table 3

[0089] Second rear sun gear 20 Second front sun gear teeth 40 Second satellite gear teeth 20 Second satellite gear teeth 20

[0090] In this case, as illustrated in Table 4 below, when the second planet carrier 102 is stationary, the transmission gear ratio (speed reduction rate) between the second front sun wheel 101 and the second rear sun gear 104 is "0.5." On the other hand, when the second rear sun gear 104 is stationary, the transmission gear ratio (speed reduction ratio) between the second front sun gear 101 and the second planet carrier 102 is also "0.5." In other words, the transmission gear ratio between the second front sun gear 101 and the second rear sun gear 104 is set to be equal to that between the second front sun gear and the second satellite carrier 102.

Table 4

[0091] Second rear sun wheel Second planet carrier 1 0.5 0 Second planet carrier Second rear sun wheel 0 0.5 1

As shown in Figure 2, the regulation mechanism 29 makes it possible to alternately stop the alternating rotational movement of the balance-spring 73, 87. More specifically, the regulation mechanism 29 is equipped with a rotation rod 120, a rotation lever 121, a first brake shoe 122, and a second brake shoe 123.

[0093] The rotation shaft 120 extends from the front to the rear. The rotation stem 120 is rotatable around the axial direction extending in the front-back direction in conjunction with, for example, the rotational actuation of the winding stem 19 around its axis.

The rotation lever 121 is fixed to the rotation rod 120. The rotation lever 121 extends on either side of the rotation rod 120 in the direction orthogonal with respect to that extending from the front to back.

The first brake shoe 122 is connected to a first end of the rotation lever 121. The second brake shoe 123 is connected to a second end of the rotation lever 121 (the end opposite the first end of the rotation lever 121). rotation 121, the rotation rod 120 being interposed between these two ends). When the rotation stem 120 is driven in rotation (rotational actuation of the winding stem 19), the first brake shoe 122 alternately comes into contact with the first balance-spring 73 (that is to say the first pendulum 82) then moves away from it; similarly, the second brake shoe 123 alternately comes into contact with the second balance-spring 87 (that is to say the second balance wheel 93), and moves away from it. More specifically, when the first brake shoe 122 and the first balance wheel 82 are brought into mutual contact, the second brake shoe 123 and the second balance wheel 93 are spaced apart. Consequently, the rotation of the first balance-spring 73 is stopped, while the rotation of the second balance-spring 87 is permitted. When the first brake shoe 122 and the first balance wheel 82 are spaced apart, the second brake shoe 123 and the second balance wheel 93 are brought into mutual contact. Consequently, the rotation of the first balance-spring 73 is permitted, while the rotation of the second balance-spring 87 is stopped.

The regulation mechanism 29 allows modifications according to needs as long as its configuration ensures that the rotation of the spiral balances 73 and 87 is alternately stopped. For example, in the present embodiment, the brake shoes 122 and 123 are arranged integrally with respect to the rotation lever 121. This, however, such a configuration should not be interpreted restrictively. The brake shoes 122 and 123 can be arranged independently of each other.

The method of regulating the sprung balance 73, 87 by the brake shoe 122, 123 is not limited to the friction force between the sprung balance 73, 87 and the brake shoe 122, 123 as 'illustrated, but allows to consider modifications according to needs. For example, an architecture may be adopted in which the balance-spring 73, 87 and the corresponding brake shoe 122, 123 are brought into mutual engagement by means of projections and recesses, or the like.

[0098] While the present embodiment described above adopts an architecture in which the brake shoe 122, 123 is brought into contact with the balance wheel 82,93 and away from it, such a configuration should not also be interpreted restrictively. It is also possible to adopt an architecture according to which the brake shoe comes into contact with and moves away from a part other than the balance wheel 82, 93 (for example, the balance shaft 81, 92) as long as the rotations of the Hairspring balances 73, 87 are alternately stopped.

As shown in Figure 4, the display plate wheel 30 has a seconds wheel 130, a minute wheel (not shown), and an hour wheel (not shown).

The seconds wheel 130 meshes with the second front sun gear toothing 101c of the second front sun wheel 101 mentioned above. The seconds hand 6 mentioned above is fitted to the seconds wheel 130. The number of teeth of the seconds wheel 130 is set so that it makes one rotation in 60 seconds.

[0101] The minute wheel meshes, for example, with the seconds wheel. The 5 minute hand is mounted on the minute wheel. The number of teeth of the minute wheel is set so that it makes one rotation in sixty minutes.

The hour wheel meshes, for example, with the minute wheel. The hour hand 4 is mounted on the hour wheel. The number of teeth of the hour wheel is set so that it rotates 12 o'clock.

Functioning

In what follows, the operation of the timepiece will be described.

[0104] The timepiece 1 of the present embodiment can be switched between two modes of operation, namely a mode at the higher frequency (first state), in which the rotation of the movement barrel 24 is controlled by the first escapement-regulator assembly 27, and a mode at the lower frequency (second state) in which the rotation of the movement barrel 24 is controlled by the second escapement-regulator assembly 28. As illustrated in FIG. 2, the switching between the modes is effected by the actuation of the regulating mechanism 29, for example, by the actuation in rotation of the winding stem 19 described above. In other words, the higher frequency mode corresponds to a state in which the first brake shoe 122 and the first balance wheel 82 are spaced from each other, and in which the rotation of the first sprung balance 73 is thus permitted. The lower frequency mode is a state in which the second brake shoe 123 and the second balance wheel 93 are spaced apart, and in which the rotation of the second hairspring 87 is thus permitted.

Higher frequency mode

Firstly, the higher frequency mode is described.

As illustrated in Figures 2 and 3, when the movement barrel 24 is driven in rotation by the energy of the barrel spring, the center wheel set 25 is in turn driven in rotation. The rotational force of the center mobile 25 is transmitted to the first front sun wheel 51 of the first differential mechanism 42, which causes the first front sun wheel 51 to also rotate.

[0107] Here, in the higher frequency mode, the rotation of the second balance-spring 87 is stopped, so that the operation of the second escapement-regulator assembly 28, of the second of the second mobiles 45, and of the first rear sun wheel 54 is put to rest. Thus, in the mode at the higher frequency, the energy of the movement barrel 24 is not transmitted to the second balance-spring 87, but it is transmitted to the first balance-spring 73. More specifically, in the mode at the higher frequency, when the first front sun wheel 51 rotates, the first planet wheel 53 rotates by making a movement of revolution around the first sun shaft 51a, 54a, and, at the same time, the first planet carrier 52 rotates. When the first planet carrier 52 rotates, the first of the second mobiles 44 is rotated, whereby the rotational force is transmitted to the first escapement mobile 71.

Under the action of the rotation of the first escapement wheel set 71, the second lever 72 rotates, thus transmitting the rotational force of the first escapement wheel set 71 to the first balance-spring 73. Due to the force of rotation of the first escapement wheel set 71 and the return force exerted by the spring of the first hairspring 83, the first hairspring balance 73 has an alternating rotational movement around the first balance shaft 81 at a fixed frequency (4 Hz). Due to the alternating rotational movement of the first balance-spring 73, the pallets 74a and 74b alternately engage with the first escapement wheel 71a and disengage therefrom. Consequently, the first escape wheel 71 rotates intermittently, while the first of the second wheels 44 and the first differential mechanism 42 (the first front sun wheel 51, the first planet carrier 52, and the first planet wheel 53) operate intermittently.

[0109] On the other hand, in the first differential mechanism 42, the rotational force of the first planet carrier 52 is transmitted to the second differential mechanism 43 via the second planet carrier 102. At this time, the first wheel rear sun wheel 54 is at rest, so that the second rear sun wheel 104 is kept at rest. Therefore, in the higher frequency mode, when the second planet carrier 102 rotates, the second planet wheel 103 rotates by making revolution movements around the second sunshaft 101a, 104a. Consequently, the second front sun wheel 101 rotates at a rotational speed equal to half that of the second planet carrier 102 (see Table 4). The rotational force of the second front sun wheel 101 is transmitted to the display train 30, through which the timepiece 1 counts and displays the time. In other words, in the mode at the higher frequency, the first balance-spring 73 performs 8 oscillations, through which the seconds hand 6 (seconds wheel 130) is caused to perform a hand movement in 8 steps every second.

Lower frequency mode

In what follows, the mode at the lower frequency will be described. Figure 9 is a plan view corresponding to Figure 2 illustrating the lower frequency mode. In the following, the description of the same operating principles as those of the higher frequency mode will not be repeated.

As shown in Figures 3 and 9, in the lower frequency mode, the rotation of the first balance-spring 73 is stopped, so that the first escapement-regulator assembly 27, the first of the second mobiles 44, and the first satellite carrier 52 are at rest. Thus, in the mode at the lower frequency, the energy of the movement barrel 24 is not transmitted to the first balance-spring 73 but it is transmitted to the second balance-spring 87. More specifically, in the mode at the frequency lower down, when the first front sun wheel 51 rotates in response to the rotation of the center wheel set 25, the first satellite wheel 53 rotates, driving the first rear sun wheel 54. Consequently, the second of the second wheel sets 45 rotates, and so the rotational force is transmitted to the second escape wheel set 85.

[0112] Following the rotation of the second escapement wheel set 85, the second anchor 86 rotates, which makes it possible to transmit the rotational force of the second escapement wheel set 85 to the second balance-spring 87. Due to the force of rotation of the second escapement wheel set 85 and the return force of the spring of the second balance spring 94, the second balance-spring 87 has an alternating rotational movement around the second balance shaft 92 at a fixed frequency (2 Hz). By means of the alternating rotational movement of the second balance-spring 87, the pallets 91a and 91b alternately engage with the second escapement wheel 85a and disengage from the latter. Consequently, the second escape wheel 85 rotates intermittently, and the second of the second wheels 45, the first differential mechanism 42 (the first front sun wheel 51, the first satellite wheel 53, and the first rear sun wheel 54) operate also intermittently.

[0113] Here, the frequency of the second balance-spring 87 is determined to be equal to half that of the first balance-spring 73. Furthermore, as indicated in Table 2, in the first differential mechanism 42, the ratio d transmission gear between the first front sun wheel 51 and the first rear sun wheel 54 when the first planet carrier 52 is fixed, and that between the first front sun wheel 51 and the first carriage 52 when the first rear sun wheel 54 is fixed are each fixed by convention as being equal to "1." Thus, the rotational speed of the movement barrel 24 in the mode at the lower frequency is equal to half that in the mode at the higher frequency.

On the other hand, as shown in Table 2, in the first differential mechanism 42, the transmission gear ratio between the first rear sun gear 54 and the first front sun gear 51, when the first carriage 52 is fixed, is equal to twice the transmission gear ratio between the first planet carrier 52 and the first front sun wheel 51 when the first rear sun wheel 54 is fixed. Thus, the rotational speed of the first rear sun wheel 54 in the lower frequency mode is identical to that of the first planet carrier 52 in the higher frequency mode. Thus, the frequency difference of the spiral balances 73.87 in the higher frequency mode and the lower frequency mode is canceled by the first differential mechanism 42, whereby in the lower frequency mode and the mode at the higher frequency, the output from the first differential mechanism 42 to the second differential mechanism 43 is equivalent.

[0115] Further, in the first differential mechanism 42, the rotational force of the first rear sun gear 54 is transmitted to the second differential mechanism 43 via the second rear sun gear 104. At this time, the first planet carrier 52 is at rest, so that the second planet carrier 102 is kept at rest. Therefore, in the lower frequency mode, when the second rear sun wheel 104 rotates, the second planet wheel 103 rotates. Therefore, the second front sun wheel 101 rotates at a rotational speed equal to half that of the second rear sun wheel 104 (see Table 4). Therefore, in both the lower frequency mode and the higher frequency mode, the rotation speed of the second front sun wheel 101 is the same. And the force of rotation of the second front sun wheel 101 is transmitted to the display train 30, through which the timepiece 1 displays and counts the time. In other words, in the mode at the lower frequency, the second balance-spring 87 performs 4 oscillations, which cause a movement of the seconds hand 6 (seconds wheel 130) in 4 steps per second.

In this way, in the present embodiment, a switch is made between the mode at the higher frequency, in which the energy delivered at the output of the movement barrel 24 can be transmitted to the first balance-spring 73, and the lower frequency mode in which energy can be transmitted to the second balance-spring 87.

In this architecture, compared to a configuration in which the two balance-springs 73 and 87 are simultaneously actuated, it is possible to reduce the energy consumption of the movement barrel 24 (in other words, to save energy). Thus, it is possible to avoid any increase in size of the movement barrel 24 by maintaining the operating time of the timepiece 1 at constant levels.

In particular, the switching mechanism 26 varies the energy of the movement barrel 24 in terms of speed depending on whether one is in the mode at the higher frequency or at the lower frequency.

According to the architecture proposed, it is possible to switch between the mode at the higher frequency and the mode at the lower frequency according to the needs. In the case, for example, of a state where the timepiece 1 is worn, and in particular in a situation in which disturbances can relatively easily occur (for example, during the practice of a sport), the timepiece is set to the higher frequency mode, through which it is possible to suppress the influence of disturbances. Therefore, it is possible to realize an improvement in time measurement accuracy.

[0120] On the other hand, in an unworn state of the timepiece 1, or in a state in which the timepiece is worn but in which it is relatively unlikely to be affected by disturbances , the timepiece is set in the mode at the lower frequency, through which it is possible to achieve an energy saving for the movement barrel 24 (i.e. of the barrel spring) , thus making it possible to increase the operating time of the timepiece 1 without requiring winding (that is to say the power reserve of the barrel). In addition, it is possible to eliminate untimely wear of all gear elements.

In the present embodiment, the first differential mechanism 42 adopts a planetary mechanism, that is to say using sun wheels and satellites.

In the architecture corresponding to this embodiment, the first differential mechanism 42 adopts a planetary mechanism by which switching between the higher frequency mode and the lower frequency mode can be easily performed. Indeed, in the mode at the higher frequency, the rotation of the second balance-spring 87 is stopped, so that the rotation of the first rear sun wheel 54 is at rest. Thus, the energy transmitted to the first front sun wheel 51 is transmitted to the first planet carrier 52 via the first planet wheel 53, and is then transmitted to the display wheel 30. On the other hand, in the mode at the lower frequency, the rotation of the first balance-spring 73 is stopped, so that the rotation of the first planet carrier 52 is at rest. Therefore, the energy transmitted to the first front sun wheel 51 is transmitted to the first rear sun wheel 54 via the first satellite wheel 53, and is then transmitted to the display train 30.

[0123] In particular, in the present embodiment, by adjusting the number of teeth of the first planet wheel 53, it is possible to make the speed of rotation of the first planet carrier 52 different from that of the first rear sun wheel. 54. Consequently, it is possible to cancel the frequency difference between the first balance-spring 73 and the second balance-spring 87 by means of the first differential mechanism 42. Thus, independently of the fact that the timepiece is located in the higher frequency mode or in the lower frequency mode, it is possible to operate the display cog 30 at a fixed rotational speed.

According to this embodiment, the second differential mechanism 43 is arranged between the first differential mechanism and the display gear 30.

[0125] In this configuration, the energy of one or the other of the elements chosen from the first planet carrier 52 and the first rear sun wheel 54 can be effectively transmitted to the display train 30.

[0126] In the present embodiment, a regulation mechanism 29 is provided which stops the reciprocating rotational movement of the second sprung balance 87 in the mode at the higher frequency, and which stops the reciprocating rotational movement of the first balance -hairspring 73 in the lower frequency mode.

[0127] In this configuration, in each mode, the reciprocating rotational movement of the balance-spring 73, 87 not contributing to the hand movement is stopped, whereby it is possible to maintain the balance-spring 83, 94 of the balance - hairspring 73, 87 not contributing to the needle movement in the extended or contracted state (it is possible to prevent it from reaching its nominal length, that is to say normal at rest). Thus, after a mode switchover, it is possible for the balance-spring 73, 87 to return quickly to normal operation.

[0128] In the present embodiment, the first differential mechanism 42 rotates the movement barrel 24 at different speeds of rotation depending on the frequencies of the first balance spring 73 and of the second balance spring 87.

According to this architecture, the movement barrel 24 is kinematically connected to the second hairspring balance 87 via the first differential mechanism 42, which makes it possible to save energy at the level of the movement barrel 24 and to increase the operating time of timepiece 1 (the life of the mainspring, that is to say its power reserve).

The timepiece 1 of this embodiment is equipped with the movement 2 mentioned above, so that it is possible to provide a timepiece 1 of high quality and of better reliability.

Implementation variants

In what follows, implementation variants for the first embodiment described above will be described.

[0132] While in the embodiment described above the first differential mechanism 42 and the second differential mechanism 43 are directly connected to each other, this should not be interpreted limitingly. For example, as shown in Figure 10, the first differential mechanism 42 and the second differential mechanism 43 can be kinematically connected to each other via the second mobiles 44, 45.

Furthermore, while in the embodiment described above the first differential mechanism 42 is kinematically connected to the second mobiles 44, 45 and to the exhaust-regulator assemblies 27, 28, this should not be interpreted as limiting either. For example, as shown in Figure 11, the first differential mechanism 42 can be kinematically connected to the second mobiles 44, 45 and to the escapement-regulator assemblies 27, 28 via the second differential mechanism 43.

[0134] Similarly, while in the embodiment described above the frequency difference between the first balance-spring 73 and the second balance-spring 87 is canceled by the first differential mechanism 42, this should not be interpreted as limiting. more. For example, the frequency difference between the first balance-spring 73 and the second balance-spring 87 can be canceled by adjusting the number of teeth of the gear element (for example that of the second mobiles 44, 45) arranged between the first differential mechanism 42 and the exhaust-regulator assemblies 27, 28.

Similarly, while in the embodiment described above, the first front sun wheel 51 is connected to the center wheel set 25, the first planet carrier 52 is connected to the first of the second wheels 44, the first wheel rear solar 54 is connected to the second of the second mobiles 45, such a configuration should not be interpreted restrictively. Indeed, in the first differential mechanism 42, it is only necessary that the center wheel 25, and the second wheels 44, 45 are separately connected to the three gear elements.

[0136] While in the embodiment described above, the rotation of the first planet carrier 52 and of the first rear sun wheel 54 is stopped according to the operating modes via the regulating mechanism 29, this should not not be construed restrictively either. For example, it is possible to separately provide a stop mechanism for the rotation of the first planet carrier 52 and for that of the first rear sun wheel 54 in each mode. In particular, in the case where no regulation mechanism 29 is provided, it is possible to switch the transmission of energy to the balance-spring 73, 87 by such a stop mechanism.

Second embodiment

In the following, a second preferred embodiment for the present invention will be described. This embodiment differs from the embodiment described above, for example, in that a first differential mechanism 242 adopts a clutch mechanism. Fig. 12 is a sectional view of the first differential mechanism 242. In the following, the components which are identical to those of the first embodiment described above are indicated by the same reference numerals, and their description will not be repeated.

[0138] In a movement 202 shown in Figure 12, the first differential mechanism 242 mainly has a front gear element 210 (first gear element), a rear gear element 211 (second gear element), an intermediate gear member 212 (third gear member), and clutch plates (a front clutch plate 213 and a rear clutch plate 214).

[0139] First, the intermediate gear member 212 has an intermediate shaft 212a, and a toothed part 212b fixed to the intermediate shaft 212a.

[0140] The intermediate shaft 212a extends through the front gear member 210 and the rear gear member 211 in the front-rear direction, and is rotatable around the front-rear axial direction. Furthermore, the intermediate shaft 212a as well as its toothed part 212b can be moved together from front to rear.

The toothed part 212b meshes with the center mobile 25 mentioned above.

[0142] The front gear element 210 is arranged in front of the toothed part 212b of the intermediate gear element 212, that is to say on the bottom side with respect to the latter. The front gear element 210 is rotatably mounted on the intermediate shaft 212a via a bearing 220. The front gear element 210 is connected to the second of the second mobiles 45 mentioned above (for example, to the second second pinion 45a ), and is connected to one of the gear elements (for example, to the second rear sun gear 104) of the second differential mechanism 43.

The rear gear element 211 is arranged at the rear of the toothed part 212b of the intermediate gear element 212, that is to say on the dial side with respect to the latter. The rear gear element 211 is rotatably mounted on the intermediate shaft 212a via a bearing 221. The rear gear element 211 is kinematically connected to the first of the second mobiles 44 mentioned above (for example, to the first second pinion 44a), and is also kinematically connected to one of the gear elements (for example, to the second planet carrier 102) of the second differential mechanism 43.

The front clutch plate 213 is fixed to the front of the toothed part 212b of the intermediate shaft 212a, that is to say on the bottom side with respect to the latter. Upon movement of intermediate gear member 212 in the forward-reverse direction, forward clutch plate 213 can be brought into contact with and away from forward gear 210. Thus, in the state in which the forward clutch plate 213 is in contact with the forward gear 210, the rotation of the forward gear member 210 relative to the intermediate gear member 212 is blocked by the frictional force between the forward clutch plate 213 and the forward gear member 210. Therefore, the intermediate gear member 212 and the forward gear member 210 rotate together. On the other hand, in the state where the front clutch plate 213 is spaced from the front gear member 210, the rotation of the front gear member 210 with respect to the intermediate gear member 212 is allowed.

The rear clutch plate 214 is fixed to the rear of the toothed part 212b of the intermediate shaft 212a, that is to say on the dial side with respect thereto. Upon movement of intermediate gear member 212 in the fore-aft direction, rear clutch plate 214 can be brought into contact with and away from rear gear member 211. The method of engagement of the clutch plates 213 and 214 with the corresponding gear elements 210 and 211 is not restricted to friction but allows variations as needed. For example, the clutch plates 213 and 214 and the corresponding gear elements 210 and 211 can be brought into mutual engagement by means of recesses and projections, or the like.

The movement 202 according to the present embodiment is equipped with a switching lever 230 actuating the movement of the intermediate gear element 212 in the forward-backward direction. The switch lever 230 can exert a compression force on the intermediate gear member 212 in the front-rear direction via, for example, the front end and the rear end of the intermediate rod 212a. The switching lever 230 can be operated, for example, by the winding stem 19.

Figure 13 is a cross-sectional view corresponding to Figure 12 to illustrate the higher frequency mode.

As shown in Fig. 13, in the higher frequency mode of the movement 202 of the present embodiment, the intermediate gear element 212 and the rear gear element 211 are positioned in a state „ mutually connected", i.e. they are integral in rotation with respect to each other, via the rear clutch plate 214 in the state in which the reciprocating rotational movement of the second rocker arm- hairspring 87 is stopped by the regulation mechanism 29. Consequently, the energy of the movement barrel 24 is transmitted to the first differential mechanism 242 via the center wheel set 25. And in the first differential mechanism 242, the gear element intermediate 212 and the rear gear element 211 rotate together, whereby the energy is transmitted to the first of the second mobiles 44 and to the second differential mechanism 43. Consequently, the display train 30 operates, and the part 1 poster and star grazes the passing time. In the higher frequency mode, the first balance-spring 73 performs 8 oscillations, so that the movement of the seconds hand 6 (seconds wheel 130) is performed in a sequence of 8 steps per second. In the higher frequency mode, the intermediate gear element 212 does not rotate relative to the front gear element 210. Therefore, the energy of the movement barrel 24 is not transmitted to the second set exhaust-regulator 28.

As illustrated in Figure 12, in the lower frequency mode, the intermediate gear element 212 and the forward gear element 210 are placed in a "mutually connected" state where they are integral in rotation relative to each other via the front clutch plate 213 in the state in which the reciprocating rotational motion of the first balance spring 73 is stopped by the regulating mechanism 29. Therefore, due to the energy transmitted to the first differential mechanism 242 via the center mobile 25, the intermediate gear element 212 and the forward gear element 210 rotate together. As a result, the energy is transmitted to the second of the second mobiles 45 and to the second differential mechanism 43, which enables the timepiece 1 to display and tell the time. In the lower frequency mode, the intermediate gear element 212 does not rotate relative to the rear gear element 211. Therefore, the energy of the movement barrel 24 is not transmitted to the first set exhaust-regulator 27.

[0150] Here, the frequency difference between the first balance-spring 73 and the second balance-spring 87 can be eliminated, for example, by taking a number of teeth of the front gear element 210 different from that of the of the rear gear element 211. More specifically, the number of teeth of the front gear element 210 and that of the rear gear element 211 are set such that the transmission gear ratio between the between the forward gear member 210 and the intermediate gear member 212 is half that between the rear gear member 211 and the intermediate gear member 212. Therefore, it is possible to suppress the frequency difference between the first balance-spring 73 and the second balance-spring 87 via the first differential mechanism 242. In other words, the rotational speed of the front gear element 210 in the mode at the frequency lower is the same as the speed rotation of the rear gear element 211 into the higher frequency mode. Thus, in the lower frequency mode, the second balance-spring 87 performs 4 oscillations, and the seconds hand 6 (the seconds wheel 130) performs a movement at a rate of 4 steps per second. The frequency difference between the first balance-spring 73 and the second balance-spring 87 can however be eliminated by the second mobile 44, 45 and the second differential mechanism 43.

[0151] In this way, according to the present embodiment, the first differential mechanism 242 adopts a clutch mechanism, by means of which the connection between the movement barrel 24 and each sprung balance 73, 87 can be easily switched when of each mode change. In particular, in the present embodiment, the number of teeth of the front gear member 210 and that of the rear gear member 211 are chosen different from each other, but at the same time, the frequency difference between the first balance-spring 73 and the second balance-spring 87 can be suppressed by the first differential mechanism 242. Consequently, it is possible to obtain the same effects as those of the embodiment described above. In the present embodiment, the regulation mechanism 29 described above may nevertheless not be employed.

[0152] While in the embodiment described above, the first differential mechanism 242 adopts a clutch mechanism, this should not be construed as limiting. A clutch mechanism made in the same way as for the first differential mechanism 242 described above can be adopted in the second differential mechanism 43.

[0153] As the clutch mechanism adopted for the second differential mechanism 243, the one-way clutch mechanism shown in Fig. 14 can be adopted. The second differential mechanism 243 shown in Fig. 14 is mainly equipped with an intermediate gear member 250, a front gear member 251, and a rear gear member 252.

[0154] The intermediate gear member 250 has an intermediate shaft 250a and a toothed part 250b fixed to the intermediate shaft 250a.

[0155] Countershaft 250a extends through front gear member 210 and rear gear member 211 from front to rear, and is rotatable about its extending axis. in the front-to-back direction.

The toothed part 250b meshes with the seconds wheel 130 of the display train 30 mentioned above.

The forward gear member 251 is supported by the intermediate shaft 250a via a forward clutch 260. The forward clutch 260 is, for example, a cam-type one-way clutch mechanism. The front clutch 260 is mainly equipped with an outer ring (not shown) fixed to the front gear member 251, an inner ring fixed to the intermediate shaft 250a, a roller (not shown) provided between the ring outer and the inner ring, and a compression element (not shown) acting against the roller. In the front clutch 260, the inner ring and the outer ring are "connected", that is to say integral with each other via the roller when the front gear element 251 tends to rotate in one direction relative to the intermediate gear member 250. In such a situation, the intermediate gear member 250 and the forward gear member 251 rotate together. However, conversely when the front gear element 251 tends to rotate in the other direction with respect to the intermediate gear element 250, the "connection" state of the inner ring with respect to the outer ring is removed and the latter are no longer integral in rotation. Therefore, in this case the rotation of the forward gear member 251 relative to the intermediate gear member 250 is then permitted.

The rear gear element 252 is supported by the intermediate shaft 250a via a rear clutch 261. The rear clutch 261 is of an architecture equivalent configuration to that of the front clutch 260 mentioned above. high. In the rear clutch 261, when the rear gear member 252 tends to rotate in one direction relative to the intermediate gear member 250, the inner ring and the outer ring are connected to each other. another via a roller. Therefore, the intermediate gear element 250 and the rear gear element 252 then rotate together. However, when the rear gear member 252 instead tends to rotate relative to the intermediate gear member 250, the connected state between the inner ring and the outer ring is suppressed. Therefore, rotation of the rear gear element 252 in the other direction relative to the intermediate gear element 250 is then permitted.

In this architecture, in the higher frequency mode, when the front gear element 251 rotates in one direction with the power transmitted from the first differential mechanism 42, the front gear element 251 and the intermediate gear element 250 are placed in a "connected" state where they are integral in rotation, and the front gear element 251 and the intermediate gear element 250 then rotate together. Consequently, the seconds wheel 130 rotates in the other direction. In the higher frequency mode, intermediate gear element 250 rotates in one direction relative to rear gear element 252 and in doing so, intermediate gear element 250 does not rotate relative to the rear gear element 252. Therefore, the energy of the movement barrel 24 is not transmitted to the second escapement-regulator assembly 28.

[0160] Conversely, in the lower frequency mode, when the rear gear element 252 rotates in one direction with the energy transmitted from the first differential mechanism 42, the rear gear element 252 and the The intermediate gear element 250 are placed in the "connected" state where they are integral in rotation, and thus the rear gear element 252 and the intermediate gear element 250 rotate together. Consequently, the seconds wheel 130 rotates in the other direction. In the lower frequency mode, the intermediate gear member 250 rotates in one direction relative to the forward gear member 251, and in doing so, the intermediate gear member 250 does not rotate relative to the forward gear member 250. to the front gear element 251. Therefore, the energy of the movement barrel 24 is not transmitted to the first escapement-regulator assembly 27.

The technical teachings of the present invention are not limited to those of the embodiments mentioned above, but allow various variations without departing from the scope of the spirit of the present invention.

[0162] For example, while in the embodiments described above, a planetary mechanism and a clutch mechanism are adopted to realize the switching mechanism, such implementations should not be interpreted in a restrictive manner. Any other type of switching mechanism is likely to do the job as long as the energy supplied by the movement barrel 24 can be transmitted to one or the other of the first balance-spring 73 or of the second balance-spring 87 In this case, the switching mechanism can, for example, have an architecture which is alternately put into gear with each second mobile 44, 45 according to the modes.

[0163] While in the embodiments described above, the frequency of the first balance-spring 73 is fixed at 4 Hz, and the frequency of the second balance-spring 87 is fixed at 2 Hz, this should not be interpreted as neither is it restrictive. The frequency of each balance-spring 73, 87 could be changed as needed.

[0164] While in the embodiments described above, two balance springs 73 and 87 are employed, this should not be interpreted restrictively either. Three or more balance springs may also be provided.

Whereas in the embodiments described above, the rotational speed of the movement barrel 24 in the mode at the lower frequency is defined as being equal to half the rotational speed of the movement barrel 24 in the higher frequency mode, this should not be interpreted restrictively either, and allows modifications as required. In this case, the speed of rotation of the movement barrel 24 can be equal in each mode.

Apart from the foregoing, and without departing from the scope or spirit of the present invention, it is possible to replace components of the embodiments described above with other well-known components as needed. Furthermore, the modifications and variants described above can be mutually combined without restrictions as required.

Claims (9)

1. Movement (2) including: a first balance-spring (73) adapted to have an alternating rotational movement; a second balance-spring (87) adapted to have an alternating rotational movement at a frequency different from that of the first balance-spring (73); an indicator needle wheel (130) provided to carry an indicator needle (6); and an energy transmission mechanism (26) adapted to be switched between a first state in which the energy delivered at the output of a movement barrel (24) is transmitted to the first balance-spring (73), and a second state in which the energy delivered at the output of the movement barrel (24) is transmitted to the second balance-spring (87), and modifying the power supplied at the output of the movement barrel (24) with the speed of rotation of the movement barrel ( 24) between the first state and the second state to rotate the indicator wheel (130) at a fixed rotational speed, which is identical between the first and the second state. 2. Movement (2) according to claim 1, wherein the energy transmission mechanism (26) is equipped with a first transmission mechanism (42) connected to the first balance-spring (73) and to the second balance-spring (87); the first transmission mechanism has three gear elements: a first sun wheel (51), a second sun wheel (54) arranged coaxially with the first sun wheel (51), and a planet carrier (52) rotatably mounted coaxially with the first sun wheel (51) and carrying a rotatable planet wheel (53) and meshing with the first sun wheel (51) and the second sun wheel (54); among the three gear elements above, a first gear element (52) transmits energy to the first balance-spring (73) in the first state, a second gear element (54) transmits energy to the second sprung balance (87) in the second state, and a third gear element (51) receives energy transmitted by the movement barrel (24). 3. Movement (2) according to claim 2, in which the planet wheel (53) causes a difference between the speed of rotation of the first gear element (52) in the first state and the speed of rotation of the second element d gear (54) in the second state. 4. Movement (2) according to claim 1, wherein the energy transmission mechanism (26) comprises a first transmission mechanism (242) kinematically connected to the first balance-spring (73) and to the second balance-spring (87). ), and the first transmission mechanism (242) has a first gear element (210) connected to the first balance-spring (73), a second gear element (211) arranged coaxially with respect to the first gear element (210) and kinematically connected to the second balance-spring (87), a third gear element (212) arranged coaxially with respect to the first gear element (210) and the second gear element (211), and kinematically connected to the movement barrel (24), and a clutch part (213,214) making the first gear member (210) rotatably secure with the third gear member (212) in the first state, and making the second gear member (211) rotatably secure with the third gear element (212) in the second state. 5. Movement (2) according to claim 4, wherein the first gear element (210) and the second gear element (212) have different numbers of teeth so that the speed of rotation of the first element of gear (210) in the first state is different from the rotational speed of the second gear element (211) in the second state. 6. Movement (2) according to one of claims 2 to 5, wherein the energy transmission mechanism (26) is equipped with a second transmission mechanism (43) transmitting the energy of one or the the other of the first gear member (52; 210) and the second gear member (54; 211) to the indicator needle wheel (130). 7. Movement (2) according to one of claims 1 to 6, wherein the energy transmission mechanism (26) is equipped with a regulating mechanism (29) which immobilizes the second balance-spring (87) in the first state, and immobilizes the first balance-spring (73) in the second state. 8. Movement (2) according to one of claims 1 to 7, wherein the energy transmission mechanism (26) is adapted to rotate the movement barrel (24) at different rotational speeds between the first state and the second state. 9. Timepiece (1), comprising a movement (2) according to one of claims 1 to 8.