Portable watch movement provided with device for adjusting frequency of 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. wristwatch, pocket watch) comprising a mechanical resonator and a setting device for setting the frequency of said resonator. The 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 the resonator of a mechanical watch. In this document, with reference to figures 50 to 54, a setting device is described which has the advantage that the frequency of the resonator can be set from outside the watch case, the setting device being arranged so that the user can set the frequency in this way. This setting device comprises a sophisticated system for correcting the frequency of the mechanical resonator whilst holding the "balance and anchor" system on the guide marks. This setting device is complex. Firstly, it comprises a clamp which holds firmly the outer turn of the spring at a given angular position of the support, called a "sector", which rotates around the axis of rotation of the balance. This clamping of the outer turn determines the effective length of the spring and therefore the frequency of the balance spring. The end turn is clamped by a sliding bar which is arranged on the watch case and which has a protruding inner part arranged so that it can act on the elastic arm of the clamp. The sliding bar can be actuated substantially tangentially to the axis of rotation of the balance 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 to clamp the outer winding and closes an access opening to the setting wheel formed in the watch case, and in a second angular position, the elastic arm is configured such that the sliding bar releases the access opening and ceases to exert a lateral force on the elastic arm so that the outer winding is not 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 with a spiral cam. The cam of the first wheel presses the second elastic arm to define 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 the aid of a tool when the sliding bar is in a second angular position and the clamp releases the outer windings of the spring. This actuation rotates the first wheel and its cam, which in turn 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 and therefore in the effective length of the spring after the clamp is closed, which in turn changes the frequency. In the following, an interesting feature of this complex setting device is explained: when the second wheel is rotated, not only does the angular position of the stud and therefore the effective length of the spring change, but the support also moves angularly in the opposite direction to the stud, over substantially the same angular distance, so that the initially set guide mark is changed without being affected. It will be prevented from being used.

[0005] The setting device is complex and has many problems. First, it consists of many parts that need to be adjusted. 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, but only when the watch movement is mounted in the case, and only through an access opening in the side of the case. One of the major problems is that the setting device consists of parts that are needed whenever the watch movement is mounted in the watch case and the frequency needs to be set. Also, the setting device requires several elastic components, in particular two elastically deformable arms and a spring, which need to be correctly sized and which may fatigue to some extent over time. Finally, the end of the outer winding of the spring is traditionally held to the stud by a transverse screw or, more frequently, by adhesive bonding. This fixing means may generate stresses in the ends of the spring, which may affect 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, consisting of 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, allowing 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 invention relates to a movement for a portable watch, comprising a mechanical resonator consisting of 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 which rotates around the axis of rotation of the balance, said movable part comprising mounting means for mounting an outer end portion of the spring and effective length defining means for defining the effective length of the spring, said effective length defining means defining an end point of the effective part of the spring at a fixed point of the movable part after the spring is mounted to the movable part by said fixing means. The setting device further comprises an effective length changing means for varying the effective length of the spring, said effective length changing means making it possible to set the frequency by angular displacement of the outer end portion relative to the movable part, and thus relative to a fixed point on the movable part, relative to the axis of rotation in a selected direction, said frequency setting being performed in combination with a rotation of the movable part in a direction opposite to the selected direction over an angular distance substantially corresponding to said angular displacement.

[0008] The movement for a portable watch 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 arranged along the outer end portion of the spring and rotatable to mesh and angularly displace with the first gear, the fixing means holding the outer end portion by friction and enabling 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 vary 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, whereby when the outer end portion is angularly displaced in the selected direction relative to the movable part, 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 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 respect to the guide mark previously set. This setting device allows the oscillation frequency to be set while automatically retaining the guide mark set in the preparation stage, and this setting device can be provided for a watch that allows such setting after the watch is fully mounted, but this setting device is self-contained and independent of the watch case, so that such a watch movement can also be mounted in a case that does not allow setting from outside the case. This setting device may seem complicated in practice with respect to the outer end part of the spring with the teeth. However, such teeth can be formed in a part that is initially separated from the spring and glued, welded or fixed by other means to the end of the outer winding of the traditional spring. In recent years, more and more springs are made of silicon, and with micromachining techniques derived from the field of microtechnology, it is not particularly problematic to form the transverse teeth on the outer end part of the spring, i.e. to prepare a blank profile of the spring with teeth. The same applies to springs made of glass or similar materials. Note that the guide marks can be set by simply pre-positioning the first tooth row with respect to the first gear with the movable part in a given initial position.

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

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

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

[0013] The portable watch movement 2 is 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 part 8 of the spring are shown in the figure), an escapement with an anchor arranged 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 the "setting device") 4 for setting the frequency of the mechanical resonator; Equipped with.

[0014] In particular, the balance is a typical balance with a plate with a pin that acts as a periodic connecting member between the anchor and the oscillating balance, so that the anchor reciprocates and oscillates in synchronism with the balance. The setting device 4 comprises a movable part 16 (called "moving part") that rotates around the balance's axis of rotation 50, the function of which is to fix the outer end part 8 of the spring 6 and to define the effective length of this spring 6. The movable part 16 and the outer end part 8 are also configured to allow setting the mechanical resonator guide marks with respect to the escape anchor. As will be seen more clearly below, the movable part 16 is also configured such that, after the resonator and setting device 4 are mounted on the watch movement 2, in order to set the oscillation frequency of the mechanical resonator, the effective length of the spring is changed while retaining the angular position of the outer end part determined at the time of fixing, thereby obtaining a stable angular position of the balance spring at rest and not losing the guide marks previously set. Thus, specifically, the effective length of the spring is varied while maintaining the correct alignment of the resting balance pin, in particular its 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 6 relative to the movable part 16 and thus the fixed point P on this movable part. FThe movement allows the frequency to be set by an 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, which is combined with a rotation of the mobile part about the axis of rotation over an angular distance in a direction opposite to the selected direction that substantially corresponds to the angular displacement (see Figures 5A and 5B). The watchmaker's movement further comprises means for setting mechanical resonator guide marks relative to the escape anchor (called "guide mark setting means") in a preparation step, which is performed when the resonator is mounted on the watchmaker's movement or when the watchmaker services the watchmaker's 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 meshes with a first gear that can be rotated to effect said angular displacement. Preferably, said spring is made of silicon or glass and is obtained by means of micromachining techniques. Thus, the first set of teeth can be easily produced when manufacturing the spring 6.

[0017] According to the invention, the fixing means hold the outer end portion 8 by friction and the first gear 22 drives said outer end portion via the first toothing 10, thus angularly displacing said outer end portion relative to the mobile 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 constituted by an upper plate 28 fixed to the resonator support, or more generally with a second toothing 30 integral with said support, so that when the outer end portion is angularly displaced in a selected direction relative to the mobile part 16, said mobile 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 arranged respectively 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 adjust the position of the spring attached to the movement 2. When the spring 6 is in an unconstrained state and thus in an unconstrained position, the first and second eccentrics are arranged to contact the first and second lateral flanks of the outer end portion 8, respectively, so that the part of the outer end portion located between the first eccentric 32 and the second eccentric 33 is spatially arranged to correspond to the spatial arrangement of the unconstrained position of the spring corresponding to any frequency setting in the useful range, and this part can maintain this spatial position when the mechanical resonator oscillates after the fixing of the outer end portion. This feature is very advantageous in order to ensure that the center of oscillation of the spring is properly on the axis of rotation 50 when the watch movement is ticking. This improves the accuracy of the watch movement. The second eccentric 33 is arranged to face the wheel 22 located on the opposite side of the second eccentric 33 with respect to the outer end portion 8. The second eccentric 33 also holds the first tooth row in the first gear 22, thus ensuring that they mesh. The various parts involved in the radial positioning of the outer end portion of the spring 6, the first gear and the radial positioning of the outer end portion are preferably machined with sufficiently low tolerances so that when the spring is in the unconstrained position, the first tooth row 10 is in meshing relationship with the first gear 22 with a certain clearance. In fact, it would otherwise be impossible to hold a portion of 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, while allowing the first tooth row of the first gear to mesh with the spring. It should be noted that the first and second eccentrics advantageously have an annular groove in which the outer end portion 8 is located. Such a groove allows the axial positioning of this 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 the first portion 9a of the outer end portion 8. The contact point at which the first eccentric mechanism presses the 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 arranged along a central portion of the outer end portion 8 of the spring 6 and a first gear wheel 22, and the guide mark is set by a preliminary angular positioning of the first tooth row relative to the first gear wheel 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 described variant, the fixing means comprises a third eccentric 34 arranged on the same side of the outer end portion of the spring as the first eccentric 32, the second eccentric 33 being arranged between the first and third eccentrics 32, 34 along the outer end portion, the first eccentric 32 being arranged towards the outer turn 7 of the spring 6 relative to the second eccentric 33. The third eccentric 34 is arranged so that it can be rotated by a tool to exert a third transverse 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 transverse force F1 and a second transverse 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 portion 9a is selected such that the first part of the outer end portion 8, which is arranged facing the first eccentric 32 when the mechanical resonator is vibrating, can remain in contact with the first eccentric. Thus, once set, the first part 9a, which is only constituted 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 precisely.

[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 an intermediate portion of said outer end portion 8, which is more flexible than the first portion 9a and which is arranged facing 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 moving 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 described, the mobile 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 as to rotate together. The second gear 24 meshes with a fixed set of teeth 30 on an upper plate 28 attached to a balance bar 14 forming 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 a rotation axis 50 via the third toothing. The plate 18 further has two elastic 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 arranged to be actuated from the lateral circumference 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 circumference via the first and second gears 22, 24. The drive device comprises a third gear 40 which meshes with an Archimedes screw 42, which has one end 42a accessible from the lateral periphery of the mechanical movement and has a non-cylindrical connection portion designed to allow connection to a member for actuating the Archimedes screw 42. Note that the upper plate 28 has a tab 28a which holds the Archimedes screw 42 in a constant 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 further relates to a watch equipped with the mechanical movement according to 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 movable 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 Device 6. Spring 7 Outer Wrapping 8 Outer end part 10 First dentition 16 Moving parts 20 Spindle 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, comprising: 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 synchronism 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) which rotates around the axis of rotation (50) of the balance, The movable part comprises an attachment 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 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); said effective length varying means making it possible to set the frequency of vibration by angular displacement of said outer end portion (8) relative to said axis of rotation in a selected direction relative to said movable part, and thus relative to a fixed point on said movable part; said setting of said frequency is performed in combination with a rotation of said movable part (16) in a direction opposite to said selected direction over an angular distance substantially corresponding to said angular displacement; The movement for a portable timepiece further comprises a guide mark setting means for setting a guide mark of a mechanical resonator relative to the anchor, the effective length varying means comprises a first gear (22) carried by the movable portion, and a first row of teeth (10) disposed along the outer end portion of the spring and rotatable to mesh with the first gear for angular displacement; said fixing means holds said outer end portion (8) by friction to enable said first gear to drive said outer end portion through said first row of teeth, thus angularly displacing said outer end portion relative to said movable part and said effective length defining means to vary the effective length of said 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 in that

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

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 and 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, such that the portions of the outer end portion between the first eccentric (32) and the second eccentric (33) are spatially arranged to substantially correspond to the spatial arrangement of the unconstrained position of the spring corresponding to any frequency setting within a useful range, the fixing means maintains this spatial position at said 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 apply a third lateral force to the outer end portion (8), whereby the first and second eccentric mechanisms react by applying a first lateral force and a second lateral force, respectively, to 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 outer end portion arranged to face the first eccentric mechanism when the mechanical resonator is vibrating, such that the first portion can remain in contact with the first eccentric mechanism.

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

6. The stiffness is selected so that the frequency of vibration can be set precisely.

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

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

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

9. The movable part (16) comprises a second gear (24) mounted coaxially with the first gear (22); the first and second gears are disposed 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 watch according to claim 1, wherein the movement is a movement for a portable watch.

10. The movable part (16) comprises a third row of teeth (38); the movement comprises a device for rotating the movable part about the axis of rotation (50) via the second tooth row (30); The drive device is configured to be actuable 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 watch according to claim 1, wherein the movement is a movement for a portable watch.

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 connection to an actuating member for actuating the Archimedes screw.

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 portable 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 portable watch. A portable watch characterized by the above.

13. The watch is provided with 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 portable watch.

12. The watch according to claim 11,

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