Actuating mechanism for a flexible display hand driven by a timepiece movement

Abstract

The present invention relates to a mechanism (1) for actuating a flexible indicator hand (20) intended to be driven by a timepiece movement of a watch, the flexible indicator hand (20) comprising a first drive-tube (16) and a second drive-tube (18), the first drive-tube (16) and the second drive-tube (18) being arranged coaxially about an axis of rotation D1, the actuating mechanism (1) comprising: - a first differential mechanism (2) comprising a first input intended to receive an angular rotation of an angle (θ1) about a rotation axis D1 transmitted by the timepiece movement and determining the rotation of the flexible indicator hand (20) about its own axis, and an output of the first differential mechanism (2) configured to rotatably drive the flexible indicator hand (20); a second differential mechanism (4) comprising a first input kinematically connected to a first input of the first differential mechanism (2) with a gear ratio, a second input intended to receive an angular rotation (θ2) determining a change in length of the flexible indicator hand (20), and an output configured to control the change in length of the flexible indicator hand (20), said output being kinematically connected to the second input of the first differential mechanism (2); Equipped with.

Description

[Technical Field]

[0001] The present invention relates to an actuation mechanism for a flexible indicator hand driven by the timekeeping movement of a timepiece. [Background technology]

[0002] Recently, the applicant has already disclosed several actuation mechanisms for flexible display hands, which are configured to control the change in shape and length of the flexible display hands while rotating them about their own axes to display time or other information in a unique manner.

[0003] However, the deployment of such an actuation mechanism requires fairly complex calculations to achieve the desired result in terms of the rotational speed and shape changes of the flexible indicator needle. Another drawback of such an actuation mechanism is that the trajectory of the flexible needle is fixed, in other words, the needle length is linked to the needle position. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention seeks to meet these and other needs by providing a mechanism for actuating a flexible indicator hand, which allows the movement of the flexible indicator hand and the changes in shape and length of the flexible indicator hand to be defined independently of each other. [Means for solving the problem]

[0005] To this end, the present invention relates to a mechanism for actuating a flexible indicator hand driven by a timepiece movement, the flexible indicator hand comprising a first drive tube connected to a first end of a first flexible arm and a second drive tube connected to a first end of a second flexible arm, the first and second flexible arms being connected together at their second ends by a tip, and the first and second drive tubes being spaced apart when the flexible indicator hand is in a free state in which no stress is applied.

[0006] When the flexible indicator hand is in the operating position, the flexible indicator hand has a defined shape and length and is in a stressed state, and the first and second drive-tubes are coaxially arranged about an axis of rotation, with the first drive-tube assembled at a first predefined stress angle and the second drive-tube assembled at a second predefined stress angle opposite the stress angle of the first drive-tube.

[0007] The actuation mechanism is configured to rotatably drive the flexible display hand and control the change in length of the flexible display hand, the first differential mechanism has a first input, the timepiece movement applies an angular rotation to the first input that determines the rotation of the flexible display hand around its axis, this angular rotation is also applied to a first input of the second differential mechanism at a certain gear ratio, an angular rotation that changes phase and determines the change in length of the flexible display hand is applied to a second input of the second differential mechanism, the output of the second differential mechanism that controls the change in length of the flexible display hand is applied to a second input of the first differential mechanism, and the output of the first differential mechanism rotatably drives the flexible display hand and controls the change in length of the flexible display hand.

[0008] Thanks to these features, the present invention provides an actuation mechanism for a flexible indicator hand, which includes a mechanism for rotatably driving the flexible indicator hand and a mechanism for controlling the change in length of the flexible indicator hand. These mechanisms are of different types, so they are separate and define the trajectory of the flexible indicator hand, allowing greater freedom to select the shape and length of the flexible indicator hand.

[0009] Thus, thanks to the separation of the function of driving the rotation of the flexible indicator hand from the function of changing its shape and length, the operating mechanism according to the invention makes it possible in a remarkable way to display two separate items of information using a single flexible indicator hand. More precisely, like any differential mechanism, the first differential mechanism of the operating mechanism according to the invention comprises two inputs and one output, the first input receiving the angular rotation imposed by the timepiece movement and ensuring the rotation of the flexible indicator hand about its own axis, the second input receiving the control command that changes the length of the flexible indicator hand and the output ensuring the drive of the flexible indicator hand.

[0010] Regarding the second differential mechanism of the actuating mechanism according to the invention, one of the inputs of the second actuating mechanism receives the angular rotation applied to the first differential mechanism by the timepiece movement via a gear ratio, the second input of the second actuating mechanism receives the phase-changing angular rotation applied by the timepiece movement and determines the change in length of the flexible display hand, and the output of the second actuating mechanism applies a command to change the length of the flexible display hand to the hand and to the second input of the first differential mechanism.

[0011] The actuation mechanism thus has two mutually independent inputs, one controlling the rotation of the flexible display hand, while the other controls its length. Thus, by way of non-limiting example only, rotation of the flexible display hand may be used to display the current time, while a change in length may be programmed to cause an alarm to sound.

[0012] This may be achieved by connecting a second input of the actuation mechanism that controls the length of the flexible indicator hand to an alarm wheel set, such as a regulator.

[0013] In particular embodiments, the invention may further comprise one or more of the following features: One or more of the following features must be considered individually or according to any technically possible combination.

[0014] In a particular embodiment, the first differential mechanism is centered on a first axis of rotation D1 and is supported by a first planet carrier, and the timepiece movement is intended to impart angular rotation to the first planet carrier.

[0015] The first planet carrier forms a first input of a first differential mechanism.

[0016] In a specific embodiment, the first differential mechanism comprises a first sun gear forming a first cannon pinion intended to support a first drive tube, and a first sun wheel set rotatably mounted coaxially with the first sun gear, the first sun wheel set comprising a second sun gear and a first sun wheel, the second sun gear forming a second cannon pinion intended to support a second drive tube.

[0017] The first sun gear and the second sun gear form the output of the first differential mechanism.

[0018] In certain embodiments, the first sun gear is configured such that the first sun gear meshes with the first intermediate wheel, the first intermediate wheel meshes with the second intermediate wheel, and the second intermediate wheel meshes with the second sun gear, and the first intermediate wheel and the second intermediate wheel are eccentrically disposed on the first planet carrier.

[0019] In certain embodiments, the second differential mechanism is centered on a second rotational axis D2 and is supported by a second planet carrier, which is rotated by the first planet carrier at a gear ratio.

[0020] The second planet carrier constitutes a first input of the second differential mechanism.

[0021] In certain embodiments, the second differential mechanism includes a second sun wheel set, the second sun wheel set being formed by a third sun gear and a second sun wheel, and the second sun wheel engaging with the first sun wheel of the first differential mechanism.

[0022] The second sun wheel forms the output of a second differential mechanism, and the first sun wheel forms the second input of a first differential mechanism.

[0023] In certain embodiments, the second differential mechanism includes a differential ring gear centered on the third sun gear, the differential ring gear having internal toothing and cooperating with the cam profile, and the second differential mechanism includes at least one planetary gear, the at least one planetary gear rolling on the internal toothing and meshing with the third sun gear.

[0024] The cam constitutes the second input of the second differential.

[0025] In a particular embodiment, the second differential mechanism comprises a rack with a toothed section, through which the rack engages with the outer toothing of the differential ring gear, and at its other end opposite the toothed section, the rack supports a cam follower pawl, through which it rests against the outer profile of the cam.

[0026] In a specific embodiment, the rotating cam can be driven with an angular rotation of an angle θ2 that determines the length of the flexible indicator hand, and as the rotating cam rotates, the rack pivots the differential ring gear, transmitting counter-rotational motion of the first sun gear and the second sun gear relative to each other through the kinematic chain of the planetary gears, the second sun gear set, the first sun gear set and the first and second intermediate gears.

[0027] In certain embodiments, the actuation mechanism comprises a control member that is operable by a user to change the length of the flexible indicator hand and, as a result of manipulation, can change the angular position of the cam.

[0028] In certain embodiments, the differential ring gear comprises cam follower pawls through which the differential ring gear rests against the cam profile.

[0029] Other features and advantages of the present invention will become apparent from the following detailed description of one embodiment of a mechanism for actuating a flexible indicator hand according to the present invention, which is given by way of example only and is in no way limiting, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a schematic cross-sectional view of one embodiment of a mechanism for actuating a flexible indicator hand according to the present invention; [Figure 2] 2 is a schematic perspective view of the actuation mechanism according to the invention shown in FIG. 1 in an exploded state; [Figure 3] 1 is a schematic top view of a flexible indicator hand intended to be driven by an actuation mechanism according to the invention, in an unassembled state; [Figure 4] 3 is a schematic diagram of the actuation mechanism of FIG. 2 in one particular embodiment of the invention, in which the differential ring gear is provided with cam follower pawls through which the differential ring gear rests against the cam profile. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention results from a general inventive idea consisting in providing an actuation mechanism for flexible display hands of a timepiece, said actuation mechanism comprising a first differential mechanism and a second differential mechanism designated by the reference numerals 2 and 4 respectively.

[0032] One embodiment of an actuation mechanism according to the present invention is shown in FIGS.

[0033] A flexible indicator hand generally referred to by the general reference numeral 20, which is drivable by an actuation mechanism 1 according to the present invention, is shown in its entirety in Figure 3 and partially in Figure 1. This flexible indicator hand 20 comprises a first drive tube 16 disposed at a first end of a first flexible arm 46 and a second drive tube 18 disposed at a first end of a second flexible arm 48. The first flexible arm 46 and the second flexible arm 48 are connected to each other at their second ends by a tip 50.

[0034] In FIG. 3, flexible indicator needle 20 is shown in its free, unstressed state, with first drive-tube 16 and second drive-tube 18 spaced apart.

[0035] However, when in the operating position, flexible indicator hand 20 is in a stressed state in which flexible indicator hand 20 is elastically deformed and first drive-tube 16 and second drive-tube 18 are coaxially aligned as shown schematically in Figure 1. In this stressed position, first drive-tube 16 is assembled at a first predefined stress angle and second drive-tube 18 is assembled at a second predefined stress angle opposite the stress angle of first drive-tube 16.

[0036] The first differential mechanism 2 is intended to accept an angular rotation applied by the timepiece movement so as to ensure rotation of the flexible indicator hand 20 about its axis. The second differential mechanism 4 is kinematically connected to the first differential mechanism 2 with a gear ratio and is intended to accept a phase-changing angular rotation applied by the timepiece movement or by the user, for example by activating a push-button. The phase-changing angular rotation determines the change in length of the flexible indicator hand 20.

[0037] The mechanism for actuating the flexible indicator hand 20 according to the invention therefore comprises two independent inputs, one intended to rotate the flexible indicator hand 20 and the other intended to change the length of the flexible indicator hand 20. Thanks to this feature, the function of rotating the hand is separated from the function of changing the shape and length of the hand, which in particular allows manufacturers and the like a great deal of freedom in determining the trajectory of the hand.

[0038] The first differential mechanism 2, which is centered on a first rotation axis D1, is supported by a first planetary carrier 6, and the timepiece movement applies an angular rotation of an angle θ1 to the first planetary carrier 6. The first differential mechanism 2 includes a first sun gear 8, which is centered on the planetary carrier 6 and is rotatably disposed on the planetary carrier 6. The first differential mechanism 2 further includes a first sun gear set 10, which is rotatably mounted coaxially with the first sun gear 8. The first sun gear 10 includes a second sun gear 12 and a first sun gear 14 fixedly mounted on the second sun gear 12.

[0039] The first sun gear 8 and the second sun gear 12 are kinematically connected to each other by a first intermediate wheel 42 and a second intermediate wheel 44, which are eccentrically mounted on the first planetary carrier 6 so as to be freely rotatable. In particular, as shown in Figures 1 and 2, the first sun gear 8 meshes with the first intermediate wheel 42, which meshes with the second intermediate wheel 44, which itself meshes with the second sun gear 12.

[0040] As will be explained in more detail below, and as can be seen in FIG. 1, the first sun gear 8 serves as a first cannon pinion for the first drive tube 16 of the flexible indicator hand 20, and the second sun gear 12 serves as a second cannon pinion for the second drive tube 18.

[0041] The flexible indicator hand 20 is therefore configured to change angular position when the first sun gear 8 and the second sun gear 12 are rotated by the timepiece movement.

[0042] It will also be appreciated that the flexible indicator hand 20 can change shape and length as the angular position of the second sun gear 12, which corresponds to the angular position of the second drive tube 18, changes relative to the angular position of the first sun gear 8, which corresponds to the angular position of the first drive tube 16, by pivoting it about the axis of rotation D1.

[0043] The second differential mechanism 4, centered on the second rotation axis D2, is supported by a second planet carrier 22, which is driven by the first planet carrier 6. The second differential mechanism 4 includes a second sun wheel set 23, which is formed by a third sun gear 24 and a second sun wheel 25, and the second sun wheel 25 engages with the first sun wheel 14 of the first differential mechanism 2. The second differential mechanism 4 further includes a differential ring gear 26 centered on the third sun gear 24. The differential ring gear 26 has inner teeth 28A and outer teeth 28B.

[0044] At least one planet gear 30 (three planet gears spaced 120° apart in the illustrated example) rolls on the internal toothing 28A of the differential ring gear 26 and meshes with the third sun gear 24. The second differential 4 further comprises a rack 32 with a toothed section 34, via which the rack 32 engages with the external toothing 28B of the differential ring gear 26. At its other end opposite the toothed section 34, the rack 32 supports a cam follower pawl 36, via which the rack 32 follows the outer profile 38 of a rotating cam 40.

[0045] As already mentioned above, the energy required for the operation of the actuating mechanism 1 according to the invention is supplied to it by the timepiece movement, which applies an angular rotation θ1 to the first planetary carrier 6 of the first differential mechanism 2. When driven by the timepiece movement, the first planetary carrier 6 therefore drives the first differential mechanism 2 rotatably about its own axis, that is, about the rotation axis D1. More specifically, the first planetary carrier 6 drives the first sun gear 8 and the second sun gear 12 rotatably about the rotation axis D1 via the rotation of the first intermediate wheel 42 and the second intermediate wheel 44 about said rotation axis D1.

[0046] It should therefore be understood that the rotation of the first planet carrier 6 ensures an angular displacement of the flexible indicator hand 20 .

[0047] Furthermore, rotation of the first planetary carrier 6 rotates the second planetary carrier 22 about the rotation axis D2. As the second planetary carrier 22 rotates, it rotatably drives one or more planetary gears 30. These planetary gears 30 roll on the internal toothing 28A of the differential ring gear 26, which in turn rotates the second sun wheel 25, which engages with the first sun wheel 14 of the first differential mechanism 2, via the third sun gear 24. Thus, rotation of the second sun gear 12 about the rotation axis D1 is also caused by rotation of the second sun wheel 25 about the rotation axis D2.

[0048] At the same time, the timepiece movement can impart an angular rotation of angle θ2 to the rotating cam 40 in order to modify the length of the flexible indicator hand 20. More specifically, the rotating cam 40 rotates to pivot the rack 32, which, by pivoting the differential ring gear 26, transmits a counter-rotational movement of the first sun gear 8 and the second sun gear 12 relative to each other through the kinematic chain formed by the planetary gear 30, the second sun gear set 23, the first sun gear set 10, the first intermediate gear 42 and the second intermediate gear 44, and the first sun gear 8. This counter-rotational movement corresponds to an angular rotation that changes the phase and alters the relative angular position of the drive tubes 16 and 18 of the flexible indicator hand 20 relative to each other, thus allowing adjustment of the flexible indicator hand 20.

[0049] It should be noted that the counter-rotational movement of the first sun gear 8 and the second sun gear 12 relative to one another is produced in particular by the first intermediate wheel 42 and the second intermediate wheel 44 .

[0050] As described above, the first differential mechanism 2 ensures the rotation of the flexible indicator hand 20 without any change in length. As an example, when the rotating cam 40 is stationary (in other words, θ2 = 0), the first sun gear 8 and the first sun wheel set 10 rotate at the same speed and in the same direction, because the gear ratio is calculated such that the speed of the first planetary carrier 6, which in this case is equal to the speed of the first sun gear 8, is equal to the speed of the first sun wheel set 10. If the first sun gear 8 and the second sun gear 12 act as the first and second cannon pinions, respectively, to which the first and second drive tubes 16 and 18 are fastened, in this scenario the flexible indicator hand 20 is rotatably driven about the rotation axis D1 while maintaining its length.

[0051] The second differential mechanism 4 ensures a change in the length of the flexible indicator hand 20 without any rotation of the flexible indicator hand 20. By way of example, when the first planetary carrier 6 is stationary (in other words θ1=0), the first sun gear 8 and the first sun wheel 10 rotate at the same speed but in opposite directions relative to each other, which rotation corresponds to a phase change in the angle between the first sun gear 8 and the second sun gear 12 due to the counter-rotational motion explained above.

[0052] It should be noted that there is no locking state between the first differential mechanism 2 and the second differential mechanism 4, because the operating mechanism 1 is configured as a whole so that the first sun wheel 14 and the second sun wheel 25 rotate with the same number of teeth when the rotating cam 40 is stationary (in other words, θ2=0).

[0053] It goes without saying that the present invention is not limited to the embodiments described above, and that those skilled in the art can think of various simple alternatives and modifications without departing from the scope of the invention as defined by the appended claims.

[0054] In particular, the term "length of the flexible indicator hand 20" should be understood to mean the radius R passing between the two drive tubes 16 and 18 and the tip 50 of this flexible indicator hand 20. It should also be noted that if the rotating cam 40 is not driven by the timepiece movement, a control member, for example a push-button, can be considered, which the user can activate from outside the watch case to change the angular position of the cam and thus modify the length of the flexible indicator hand 20.

[0055] More specifically, by moving the cam from a first position to a second position different from the first position, the phase change between the flexible arms 46, 48 of the flexible indicator hand 20 can be changed, and therefore the length of the flexible indicator hand 20 can also be changed.

[0056] Then, if the position of the cam remains unchanged, the flexible indicator hand 20 will simply rotate about its own axis without changing its length. Thus, by modifying the length of the flexible indicator hand 20, it is possible, for example, to orient the tip 50 of this flexible indicator hand 20 towards one of two separate scales and thus to indicate the values ​​of two different parameters.

[0057] Thus, for example, the angle that the flexible display hand 20 forms in its initial position may be used to provide an indication of the current time, while the length and / or shape of the flexible display hand 20 provides the user with an indication of the power reserve of the watch.

[0058] FIG. 4 shows a particular embodiment of the invention in which a differential ring gear 26 is provided which does not have teeth on its outer periphery but has cam follower pawls 52, via which the differential ring gear 26 rests against the outer periphery 38 of the cam 40.

Claims

1. A mechanism (1) for actuating a flexible indicator hand (20) intended to be driven by a timekeeping movement of a timepiece, said flexible indicator hand (20) comprising a first drive tube (16) connected to a first end of a first flexible arm (46) and a second drive tube (18) connected to a first end of a second flexible arm (48), said first flexible arm (46) and said second flexible arm (48) having distal ends a first drive-tube (16) and a second drive-tube (18) connected together at second ends of the first and second flexible arms (46) and (48) by a tension spring (50), the flexible indicator hand (20) being in a stressed state when the flexible indicator hand (20) is in an operating position and having a predefined shape and length, the first drive-tube (16) and the second drive-tube (18) being coaxially arranged about a rotation axis (D1), and the actuation mechanism (1) comprising: a first differential mechanism (2) comprising a first input intended to receive an angular rotation of an angle (θ1) about the axis of rotation D1 transmitted by the timepiece movement and determining the rotation of the flexible indicator hand (20) about its own axis, and an output of the first differential mechanism (2) configured to rotatably drive the flexible indicator hand (20); a second differential mechanism (4) comprising a first input kinematically connected to the first input of the first differential mechanism (2) with a gear ratio, a second input intended to receive an angular rotation (θ2) determining the change in length of the flexible indicator hand (20), and an output configured to control the change in length of the flexible indicator hand (20), said output being kinematically connected to the second input of the first differential mechanism (2); An actuation mechanism (1), characterized in that it comprises:

2. 2. The actuation mechanism (1) according to claim 1, characterized in that the first differential mechanism (2) is centered on a first rotation axis D1 and is supported by a first planet carrier (6), and the timekeeping movement imparts an angular rotation of the angle (θ1) to the first planet carrier (6).

3. 3. The actuation mechanism (1) according to claim 2, characterized in that the first differential mechanism (2) comprises a first sun gear (8) forming a first cannon pinion intended to support the first drive tube (16) and a first sun wheel set (10) mounted rotatably and coaxially with the first sun gear (8), the first sun wheel set (10) comprising a second sun gear (12) and a first sun wheel (14), the second sun gear (12) forming a second cannon pinion intended to support the second drive tube (18).

4. 4. The actuation mechanism (1) according to claim 3, wherein the first sun gear (8) is configured such that the first sun gear (8) meshes with a first intermediate wheel (42), the first intermediate wheel (42) meshes with a second intermediate wheel (44), and the second intermediate wheel (44) meshes with the second sun gear (12), and the first intermediate wheel (42) and the second intermediate wheel (44) are eccentrically arranged on the first planet carrier (6).

5. 5. The actuation mechanism (1) according to any one of claims 2 to 4, characterized in that the second differential mechanism (4) is centered on a second rotation axis D2 and is supported by a second planet carrier (22), the second planet carrier (22) being rotated by the first planet carrier (6) at a gear ratio.

6. The actuation mechanism (1) of claim 5, characterized in that the second differential mechanism (4) comprises a second sun wheel set (23), which is formed by a third sun gear (24) and a second sun wheel (25), and the second sun wheel (25) engages with the first sun wheel (14) of the first differential mechanism (2).

7. 7. The actuation mechanism (1) according to claim 6, characterized in that the second differential mechanism (4) comprises a differential ring gear (26) centered on the third sun gear (24), the differential ring gear (26) having internal toothing (28A) and cooperating with an outer portion (38) of a cam (40), and the second differential mechanism (4) further comprises at least one planetary gear (30), the at least one planetary gear (30) rolling on the internal toothing (28A) and meshing with the third sun gear (24).

8. 8. The actuation mechanism (1) according to claim 7, characterized in that the second differential mechanism (4) comprises a rack (32) with a toothed section (34), the rack (32) engaging with the external toothing (28B) of the differential ring gear (26) via the toothed section (34), and at its other end opposite to the toothed section (34), the rack (32) supports a cam follower pawl (36), the rack (32) resting against the outer portion (38) of the cam (40) via the cam follower pawl (52).

9. 9. The actuation mechanism (1) according to claim 4 or 8, characterized in that the rotating cam (40) can be driven to rotate by an angle (θ2) that determines the length of the flexible display hand (20), and when the rotating cam (40) rotates, the rack (32) pivots the differential ring gear (26), transmitting counter-rotational movements of the first sun gear (8) and the second sun gear (12) relative to each other through a kinematic chain formed by the planetary gear (30), the second sun gear set (23), the first sun gear set (10), and the first intermediate gear (42) and the second intermediate gear (44).

10. 10. The actuation mechanism (1) according to claim 9, characterized in that the actuation mechanism (1) comprises a control member which can be actuated by a user to change the length of the flexible indicator hand (20) and which, as a result of its operation, can change the angular position of the cam (40).

11. 8. The actuation mechanism (1) according to claim 7, characterized in that the differential ring gear (26) comprises cam follower pawls (52), and the differential ring gear (26) rests against the outer portion (38) of the cam (40) via the cam follower pawls (52).

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