A movement for a portable watch, including a device for setting the frequency of a mechanical resonator

Abstract

To provide a setting device for effectively setting a frequency of a mechanical movement.SOLUTION: A movable part 16 of a setting device for setting the frequency of a mechanical resonator includes means for attaching an end outer portion 8 and effective length defining means for defining an effective length of a spring, wherein the effective length changing means for changing the effective length of the spring is provided with a first gear 22 carried by the movable part and a first tooth row 10 arranged along the outer end portion 8 of the spring and engaged with the first gear. Fixing means hold the outer end portion 8 by friction, so that the first toothed wheel can drive the outer end portion 8 via the first toothing 10 and thus change the effective length of the spring. The first gear is in meshing relationship with a second set of teeth integral with the support of the first resonator, so that, when the outer end portion performs an angular displacement in a selected direction with respect to the movable part, the movable part is simultaneously angularly displaced by a corresponding angular distance in the opposite direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a movement for a watch (e.g., a wristwatch, a pocket watch) comprising a mechanical resonator and a setting device for setting the frequency of said resonator. The present invention further relates to a setting device for setting guide marks of an escapement associated with the mechanical resonator.

[0002] In particular, the invention relates to a setting device for setting the frequency of the resonator of a mechanical watch in such a way that it does not affect the previously set guide marks of the "balance and anchor" system. [Background technology]

[0003] Belgian Patent Application BE483992A describes various embodiments of a setting device for setting the frequency of a balance spring forming a resonator in a mechanical watch. With reference to Figures 50-54, this document describes a setting device that advantageously allows the frequency of the resonator to be set from outside the watch case, allowing the user to set the frequency in this manner. This setting device includes a sophisticated system for correcting the frequency of the mechanical resonator while maintaining the "balance and anchor" system on guide marks. This setting device is complex. First, the system includes a clamp that securely holds the outer turns of the spring at a given angular position of a support, called a "sector," that rotates around the balance's axis of rotation. This clamping of the outer turns determines the effective length of the spring and, therefore, the frequency of the balance spring. The terminal turns are clamped by a sliding bar located on the watch case, which has a protruding inner portion that can act on the elastic arm of the clamp. The sliding bar can be actuated in a direction substantially tangential to the balance's rotation axis by an actuating member of the sliding bar accessible from the outside of the case. In a first angular position of the sliding bar, the sliding bar presses the elastic arm laterally, clamping the outer winding and closing an access opening to the setting wheel formed in the watch case, and in a second angular position, the sliding bar releases the access opening and ceases to exert a lateral force on the elastic arm, so that the outer winding is no longer held by the clamp. The setting device further comprises a stud attached to a second elastic arm of the support and two meshing wheels, each equipped with a spiral cam. The cam of the first wheel presses the second elastic arm to determine the angular position of the stud and its angular distance from the clamp. The second wheel cam presses against a third spiral cam, which is fixed but whose angular position can be adjusted by the watchmaker when setting the initial guide marks, and the second wheel cam is held against the fixed cam by elastic means to actuate the rotation of the support.

[0004] To set the frequency of the resonator, the second wheel can be actuated with a tool when the sliding bar is in a second angular position and the clamp has released the outer windings of the spring. This actuation rotates the first wheel and its cam, which moves the second elastic arm, changing the angular position of the stud and therefore the angular distance between this stud and the clamp. This results in a change in the active distance after the clamp is closed, and therefore also in a change in the effective length of the spring, which in turn changes the frequency. An interesting feature of this complex setting device is explained below: rotating the second wheel not only changes the angular position of the stud and therefore the effective length of the spring, but also moves the support angularly in the opposite direction to the stud, over substantially the same angular distance, changing the initially set guide mark without affecting it. It is made so that this cannot be done.

[0005] The above-described setting device is complex and presents many challenges. First, the setting device is comprised of many parts that require adjustment. The machining of certain parts is complicated, as is the assembly of the setting device. Another major problem is that the oscillation frequency cannot be set after the watch movement is completed; it can only be set when the watch movement is attached to the case, and only through an access opening in the side of the case. One major problem is that the setting device is comprised of parts that are required whenever the frequency needs to be set after it is attached to the watch case. Furthermore, the setting device requires several elastic components, specifically two elastically deformable arms and a spring, which must be correctly sized and may fatigue to some extent over time. Finally, the outer winding end of the spring is traditionally held to a stud by a transverse screw or, more frequently, by adhesive bonding. This fastening method can create stress on the end of the spring, potentially affecting the accuracy of the frequency setting. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention aims to solve the problems of the prior art mentioned in the background by providing a watch movement with a mechanical resonator, which comprises a balance spring and a setting device for setting the frequency of the mechanical resonator, which is uncomplicated, reliable and independent of the watch case, and which allows the frequency to be set effectively without changing the initial setting of the guide marks. [Means for solving the problem]

[0007] In this context, the present invention relates to a movement for a watch, comprising a mechanical resonator constituted by a balance rotatably mounted on a support and a spring, an escapement including an anchor configured to vibrate in synchronization with said balance, and a setting device for setting the oscillation frequency of said mechanical resonator, said setting device having a movable part that rotates around the axis of rotation of said balance, said movable part comprising mounting means for mounting an outer end part of said spring and effective length defining means for defining the effective length of said spring, said effective length defining means defining the end point of the effective part of said spring at the fixing point of said movable part after said spring has been attached to said movable part by said fixing means. The setting device further comprises an effective length changing means for changing the effective length of the spring, which makes it possible to set the frequency by angular displacement of the outer end portion relative to the movable part, and therefore relative to a fixed point on the movable part, relative to the axis of rotation in a selected direction, the setting of the frequency being performed in combination with rotation of the movable part in a direction opposite to the selected direction over an angular distance substantially corresponding to the angular displacement.

[0008] The watch movement further comprises a guide mark setting means for setting a guide mark of the mechanical resonator relative to the anchor. The effective length changing means comprises a first gear carried by the movable part and a first tooth row disposed along the outer end portion of the spring and rotatable to mesh with the first gear for angular displacement, and the fixing means holds the outer end portion by friction and allows the first gear to drive the outer end portion via the first tooth row, thus angularly displacing the outer end portion relative to the movable part and the effective length defining means to change the effective length of the spring. Finally, the first gear is in meshing relationship with a second tooth row integral with the support of the resonator, such that when the outer end portion is angularly displaced relative to the movable part in the selected direction, the movable part is simultaneously angularly displaced an opposite angular distance. Thus, the outer end portion does not undergo any angular displacement and the previously set guide marks remain unchanged.

[0009] The setting device of the present invention does not require a spring. It is sufficient to provide a means for actuating the first gear or moving part to set the resonator frequency without misalignment with the previously set guide mark. This setting device allows the oscillation frequency to be set while automatically maintaining the guide mark set during the preparation stage. This setting device can be provided for a watch that allows such setting after the watch is fully installed, but because this setting device is self-contained and independent of the watch case, such watch movements can also be installed in cases that do not allow setting from outside the case. This setting device may appear complicated in practice, particularly with regard to the outer end portion of the spring with the teeth. However, these teeth can be formed on a part initially separate from the spring and then glued, welded, or fixed to the end of the outer winding of a traditional spring by other means. Recently, springs have become increasingly made of silicon, and using micromachining techniques derived from the field of microtechnology, forming transverse teeth on the outer end portion of the spring, i.e., preparing a blank profile for the spring with the teeth, is not particularly problematic. The same applies to springs made of glass or similar materials. The guide marks can be set simply by pre-positioning the first tooth row relative to the first gear with the moving part in a given initial position.

[0010] The invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view from above of an embodiment of a watch movement according to the present invention, showing the watch movement assembly with the setting device and the outer end portion of the spring. [Figure 2]2 is a top view of the movement assembly for a watch shown in FIG. 1, with the upper plate visible and its outline shown in dashed lines (excluding the toothing). [Figure 3] 2 is a perspective view of the movement assembly for the watch of FIG. 1 from above with the upper plate removed. FIG. [Figure 4] FIG. 2 is a partial perspective view from below of the outer end portion of the assembly and spring shown in FIG. 1; [Figure 5] 5A and 5B are bottom partial views of the outer end portion of the assembly and spring shown in FIG. 1, respectively, with the movable portion in two different positions corresponding to two different effective lengths of the spring. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, a portable timepiece movement according to the present invention will be described with reference to the drawings.

[0013] Portable watch movement 2 a mechanical resonator constituted by a balance rotatably mounted on a support (only the balance bar 14 forming this support is shown in the figure) and a spring 6 (only the outer winding 7 and the outer end portion 8 of the spring are shown in the figure), - an escapement with an anchor adapted to oscillate in synchronism with the balance (the escapement, in particular a traditional watch escapement with a Swiss anchor, is not shown in the figures); - a setting device (called "setting device") 4 for setting the frequency of the mechanical resonator; Equipped with.

[0014] In particular, the balance is a typical balance comprising a plate with a pin that acts as a periodic connecting member between the anchor and the oscillating balance, causing the anchor to reciprocate and oscillate in synchronization with the balance. The setting device 4 comprises a movable part 16 (referred to as "moving part") that rotates around the balance's rotation axis 50, the function of which is to fix the outer end portion 8 of the spring 6 and thereby determine its effective length. The movable part 16 and the outer end portion 8 are also configured to allow the mechanical resonator guide marks to be set relative to the escape anchor. As will be more clearly understood below, after the resonator and setting device 4 are mounted on the watch movement 2, the movable part 16 is configured such that, in order to set the oscillation frequency of the mechanical resonator, the effective length of the spring changes while maintaining the angular position of the outer end portion determined during fixation, thereby obtaining a stable angular position of the balance spring at rest and not losing the previously set guide marks. Thus, the effective length of the spring is varied while maintaining proper alignment of the balance pin at rest, particularly radial alignment on the balance axis of rotation and the anchor axis of rotation.

[0015] Thus, in general, the movable part 16 comprises a means for attaching the outer end portion 8 of the spring 6 (called the "fixing means") and a fixing point P on the movable part 16 after the spring is fixed to the movable part by the fixing means. F At the end point P on the effective part of the spring 6 E The setting device 4 further comprises means for changing the effective length of the spring (called "effective length changing means"), which determines the effective length of the spring relative to the movable part 16 and thus the fixed point P on this movable part. FThe resonator allows the frequency to be set by angular displacement of the outer end portion 8 about the axis of rotation 50 in a selected direction relative to the movement of the watchmaker. This angular displacement is combined with a rotation of the moving part about the axis of rotation in a direction opposite to the selected direction over an angular distance that substantially corresponds to the angular displacement (see Figures 5A and 5B). The watch movement further comprises means for setting mechanical resonator guide marks relative to the escape anchor (referred to as "guide mark setting means") in a preparation step that is carried out when the resonator is fitted to the watch movement or when a watchmaker services the watch movement.

[0016] According to the invention, the effective length varying means comprises a first gear 22 carried by a plate 18 on the movable part 16 and a first set of teeth 10 arranged along the outer end portion 8 of the spring, which first set of teeth 10 mesh with a first gear that can be rotated to effect said angular displacement. Preferably, the spring is made of silicon or glass and is obtained using micromachining techniques. Therefore, the first set of teeth can be easily produced when manufacturing the spring 6.

[0017] According to the invention, the fixing means frictionally hold the outer end portion 8, and the first gear 22 drives this outer end portion via the first toothing 10, thus angularly displacing it relative to the movable part 16 and the effective length defining means, thereby varying the effective length of the spring 6. The first gear 22 is in meshing relationship with a fixed toothing 30 formed by an upper plate 28 fixed to the resonator support, or more generally with a second toothing 30 integral with this support, so that when the outer end portion is angularly displaced in a selected direction relative to the movable part 16, this part is simultaneously angularly displaced an angular distance in the opposite direction.

[0018] In the preferred variant shown in the figures, the fixing means further comprise a first eccentric 32 and a second eccentric 33 respectively arranged on either side of the outer end portion 8 of the spring 6. These first and second eccentrics can each be rotated by a tool to fix the spring to the movement 2. When the spring 6 is in an unconstrained state, the first and second eccentrics are respectively in contact with the first and second lateral flanks of the outer end portion 8 when the spring 6 is in the unconstrained position. This allows the portion of the outer end portion located between the first eccentric 32 and the second eccentric 33 to be spatially positioned to correspond to the spatial position of the spring in the unconstrained position corresponding to any frequency setting within the useful range, and this portion can maintain this spatial position when the mechanical resonator vibrates after the outer end portion is secured. This feature is highly advantageous for ensuring that the center of oscillation of the spring is properly located on the rotation axis 50 when the watch movement is ticking. This improves the accuracy of the watch movement. The second eccentric 33 is positioned opposite the wheel 22 located on the opposite side of the second eccentric 33 relative to the outer end portion 8. The second eccentric 33 also holds the first teeth 10 in the first gear 22, thus ensuring their meshing. The various components involved in the radial positioning of the outer end portion of the spring 6, the first gear, and the outer end portion are preferably machined to sufficiently low tolerances so that the first teeth 10 are in meshing relationship with the first gear 22 with a certain clearance when the spring is in the unconstrained position. Indeed, it would otherwise be impossible to mesh the first teeth 10 of the first gear with the first gear 22 while holding the outer end portion 8 between the first and second eccentrics 32, 33 with a spatial arrangement corresponding to the unconstrained position of the spring. The first and second eccentrics advantageously have annular grooves in which the outer end portion 8 is located. Such grooves allow for axial positioning of the outer end portion 8.

[0019] The effective length determining means for determining the effective length of the spring 6 is constituted by a first eccentric mechanism 32 that presses against the first portion 9a of the outer end portion 8. The contact point at which the first eccentric mechanism presses against this first portion 9a is the end of the effective portion of the spring, and therefore the end point P of the effective length of the spring. E This end point is at a fixed contact point with respect to the moving part, so that the end point is always at a specific fixed point P F , i.e., an invariant point on the moving part.

[0020] The guide mark setting means comprises a first tooth row 10 on the spring 6 located along the central portion of the outer end portion 8 of the spring 6 and a first gear 22, and the guide mark is set by preliminary angular positioning of the first tooth row relative to the first gear while the movable part 16 is in a given initial angular position, which can be anywhere in the angular travel of the movable part, but is preferably substantially in the middle of this angular travel.

[0021] In the variant described, the fixing means comprise a third eccentric 34 arranged on the same side of the outer end portion of the spring as the first eccentric 32, a second eccentric 33 arranged between the first and third eccentrics 32, 34 along the outer end portion, the first eccentric 32 being arranged towards the outer turns 7 of the spring 6 relative to the second eccentric 33. The third eccentric 34 is configured to be rotated by a tool so as to exert a third lateral force F3 on the outer end portion 8, so that, when the first gear 22 is not rotating, the first and second eccentrics 32, 33 react by exerting a first lateral force F1 and a second lateral force F2, respectively, on the outer end portion 8, which is held in place by frictional forces between the outer end portion 8 and the first, second and third eccentrics.

[0022] According to one advantageous feature, the first lateral force F1 has a magnitude and the stiffness of said first part 9a is selected so that the first part of the outer end portion 8, which is arranged facing the first eccentric 32, can remain in contact with the first eccentric when the mechanical resonator is vibrating. Thus, once set, the first part 9a, which is formed only by the eccentric 32, remains in contact with the means for determining the effective length of the spring, even though it is only in contact on one side with the means for determining the effective length of the spring. When the oscillator is vibrating, the effective length of the spring remains constant. In particular, the stiffness of the first portion 9a is selected so that the frequency of vibration can be set accurately.

[0023] According to a particular feature of the fixing means, the outer end portion 8 has a terminal portion 9b, located after the first row of teeth 10 occupying the middle part of said outer end portion 8, which is more flexible than the first portion 9a and is arranged opposite a third eccentric mechanism 34 capable of exerting a third lateral force F3 on said terminal portion 9b. Preferably, the width of the terminal portion 9b increases towards its free end, so that the third lateral force F3 remains substantially constant for any frequency setting and therefore for any effective length within the expected setting range.

[0024] In the embodiment being described, the moving part 16 has a second gear 24 mounted coaxially with the first gear 22, the first and second gears being fixed to the same spindle 20 so that they rotate together. The second gear 24 meshes with fixed teeth 30 on an upper plate 28 attached to a balance bar 14 which forms part of the mechanical resonator support.

[0025] In a particular variant, the mobile part 16 has a third toothing 38 carried by an arm 18a of the plate 18, and the mechanical movement 2 comprises a device for rotating the mobile part about an axis of rotation 50 via the third toothing. The plate 18 further comprises two resilient arms 18b and 18c forming a split ring surrounding the support of a shock-resistant bearing 46, by means of which the mobile part 16 is guided in rotation. The drive device is configured to be actuated from the lateral periphery of the movement to rotate the mobile part 16 and to generate a change in the effective length of the spring 6 from this lateral periphery via the first and second gear wheels 22, 24. The drive device comprises a third gear 40 that meshes with an Archimedes screw 42, which has one end 42a accessible from the lateral periphery of the mechanical movement and a non-cylindrical coupling portion designed to allow connection to a member for actuating the Archimedes screw 42. Note that the upper plate 28 has a tab 28a that holds the Archimedes screw 42 in a fixed longitudinal position, so that as the Archimedes screw 42 rotates, the gear 40 is driven in rotation even when no longitudinal pressure is applied to the Archimedes screw 42.

[0026] The present invention also relates to a watch equipped with the mechanical movement of the present invention. This watch has a case (not shown) that houses the mechanical movement 2, and is configured so that the drive device of the moving part can be actuated by the actuating member (not shown) that can be operated from outside the watch. [Explanation of symbols]

[0027] 2. Movement 4. Setting Devices 6 Spring 7 Outer wrapping 8 Outer end part 10 First dentition 16 Moving parts 20 spindles 22 First Gear 24 Second Gear 30 Second dentition 32 First eccentric mechanism 33 Second eccentric mechanism 34 Third eccentric mechanism 38 Third dentition 42 Archimedes screw 50 Balance axis

Claims

1. A movement (2) for a portable watch, a mechanical resonator consisting of a balance rotatably mounted on a support and a spring (6); an escapement including an anchor configured to oscillate in synchronization with the balance; a setting device (4) for setting the oscillation frequency of the mechanical resonator, The setting device (4) has a movable part (16) that rotates around the axis of rotation (50) of the balance, The movable part comprises a fixing means for attaching the outer end portion (8) of the spring and an effective length defining means for defining the effective length of the spring; The effective length defining means is configured to define a fixed point (P) of the movable part (16) after the spring is attached to the movable part by the fixing means. F ) at the end point (P E ) and The setting device further comprises an effective length changing means for changing the effective length of the spring (6); the effective length varying means allows the frequency to be set by angular displacement of the outer end portion (8) relative to the axis of rotation in a selected direction relative to the movable part, and therefore relative to a fixed point on the movable part; setting the frequency in combination with a rotation of the movable part (16) in a direction opposite to the selected direction over an angular distance substantially corresponding to the angular displacement; the movement for a portable timepiece further comprises a guide mark setting means for setting a guide mark of the mechanical resonator relative to the anchor; the effective length changing means comprises a first gear (22) carried by the movable part, and a first row of teeth (10) arranged along the outer end portion of the spring and rotatable to mesh with the first gear for angular displacement; the fixing means holds the outer end portion (8) by friction and allows the first gear to drive the outer end portion through the first row of teeth, thus angularly displacing the outer end portion relative to the movable part and the effective length defining means to vary the effective length of the spring; The first gear (22) is in meshing relationship with a second set of teeth (30) integral with the support of the resonator, whereby when the outer end portion is angularly displaced in the selected direction relative to the movable portion, the movable portion is simultaneously angularly displaced an opposite angular distance. A movement for a portable watch characterized by the above.

2. The spring (6) is made of silicon or glass and is obtained by micromachining technology.

2. The movement for a portable watch according to claim 1.

3. the fixing means comprise a first eccentric (32) and a second eccentric (33) arranged on either side of the outer end portion (8) of the spring and rotatable by means of a tool, so that when the spring (6) is mounted in the watch movement, while the spring is in an unconstrained position, the first eccentric (32) and the second eccentric (33) are in contact with first and second lateral flanks of the outer end portion (8), respectively, and the portions of the outer end portion between the first eccentric (32) and the second eccentric (33) are spatially arranged in such a way that they substantially correspond to the spatial arrangement of the spring in its unconstrained position corresponding to any frequency setting within a useful range; the fixing means maintains this spatial position at the portion of the outer end portion after being fixed; The first eccentric mechanism (32) constitutes the effective length defining means.

2. The movement for a portable watch according to claim 1.

4. the fixing means comprises a third eccentric mechanism (34) arranged on the same side of the outer end portion (8) of the spring as the first eccentric mechanism (32); the second eccentric mechanism (33) is located between the first eccentric mechanism and the third eccentric mechanism along the outer end portion; the first eccentric is located towards the outer turn (7) of the spring relative to the second eccentric, The third eccentric mechanism (34) can be rotated by a tool to exert a third lateral force on the outer end portion (8), whereby the first and second eccentric mechanisms react by exerting a first lateral force and a second lateral force, respectively, on the outer end portion to hold it in place due to friction between the outer end portion and the first, second and third eccentric mechanisms when the first gear is not rotating.

4. The movement for a portable watch according to claim 3.

5. The first lateral force has a magnitude and a stiffness of the first portion of the outer end portion, which is positioned opposite the first eccentric mechanism, is selected so that the first portion can remain in contact with the first eccentric mechanism when the mechanical resonator is vibrating.

5. The movement for a portable watch according to claim 4.

6. The stiffness is selected so that the frequency can be set accurately.

6. The movement for a portable watch according to claim 5.

7. the outer end portion has a terminal portion located behind the first row of teeth and more flexible than the first portion; the end portion is disposed opposite the third eccentric mechanism; The third eccentric mechanism is capable of exerting the third lateral force on the terminal portion.

6. The movement for a portable watch according to claim 5.

8. the guide mark setting means is configured by the first tooth row of the spring and the first gear, The guide mark is set by preliminary positioning of the first tooth row relative to the first gear while the movable part is in a predetermined angular position.

8. The movement for a portable timepiece according to claim 1, wherein the movement is a movement for a portable timepiece.

9. The movable part (16) comprises a second gear (24) mounted coaxially with the first gear (22); the first and second gears are arranged on the same spindle (20) so as to rotate together; The second gear (24) meshes with the second tooth row (30).

8. The movement for a portable timepiece according to claim 1, wherein the movement is a movement for a portable timepiece.

10. the movable part (16) comprises a third row of teeth (38); the movement comprises a drive device for rotating the movable part about the rotation axis (50) via the third tooth row (38); The drive device can be actuated by an actuating member from a lateral periphery of the movement to rotate the movable part (16), thereby generating a change in the effective length of the spring from this lateral periphery via the first and second gears.

8. The movement for a portable timepiece according to claim 1, wherein the movement is a movement for a portable timepiece.

11. The drive device comprises an Archimedes screw (42); One end of the Archimedes screw (42) is accessible from the lateral periphery of the movement and has a non-cylindrical connection portion that allows it to be connected to the actuating member.

11. The movement for a portable watch according to claim 10.

12. A portable timepiece comprising the portable timepiece movement according to claim 10, The watch has a case that houses the movement (2), and is configured so that the drive device of the movable part (16) can be actuated by the actuating member that can be operated from the outside of the watch. A portable watch characterized by the above.

13. A portable watch equipped with the portable watch movement according to claim 11, The watch has a case that houses the movement (2), and is configured so that the drive device of the movable part (16) can be actuated by the actuating member that can be operated from the outside of the watch. A portable watch characterized by the above.

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