Patent Application
20200333746
The present invention relates to devices for timepieces, and also to clockwork movements and timepieces comprising such devices.
Devices are known for timepieces comprising a monolithic mechanism which comprises:
Document US 2013/176829 A1 describes an example of such a device.
The known devices of this type have the disadvantage that manufacturing tolerances induce dispersions in the oscillation frequency f, and therefore in the temporal precision of the device.
The purpose of the present invention is especially to remedy this drawback.
For this purpose, according to the invention, a device of the type in question is characterized in that the elastic suspension comprises an elastic adjustment link having a first end linked to said at least one inertial regulating member and a second end which is connected to the support by a frequency adjustment device suited to modify the position of the second end of said elastic adjustment link relative to the support, so as to change the overall stiffness of the elastic suspension and therefore said frequency f.
Because of these dispositions, the oscillation frequency f can be adjusted and therefore the dispersions due to the manufacturing tolerances compensated.
In various embodiments the mechanism according to the invention, one and/or another of the following dispositions could further be used:
Furthermore, the invention also relates to a clockwork movement comprising the device such as described above and said energy distribution member.
Finally, the invention also relates to a timepiece comprising a movement such as defined above.
Other features and advantages of the invention will become apparent during the following description of two of the embodiments thereof, given as a nonlimiting example, with reference to the attached drawings.
In the drawings:
In the various figures, the same references designate identical or similar items.
As shown schematically in
The pallet 11 and the regulator 12 form a monolithic mechanism 13, as will be explained below.
The clockwork movement 3 is now going to be explained in more detail with the help of
The plate 14 can be thin, for example about 0.05 mm to about 1 mm, according to the type of material for the plate 14.
The plate 14 can have transverse dimensions, in the XY plane of the plate (in particular length and width, or diameter), included between about 10 mm and 40 mm. X and Y are two perpendicular axes defining the plane of the plate 14.
The plate 14 can be made from any suitable stiff material preferably having a small Young's modulus for presenting good elasticity properties and a low oscillation frequency. Examples of materials that can be used to make the plate 14 include silicon, nickel, iron-nickel alloy, steel and titanium. In the case of silicon, the thickness of the plate 14 may for example be included between 0.2 mm and 0.6 mm.
The various members formed in the plate 14 are obtained by making openings in the plate 14 obtained by any fabrication method used in micromechanics, in particular methods used for MEMS fabrication.
In the case of a plate 14 of silicon, the plate can be locally hollowed and milled for example by deep reactive ion etching (DRIE) or possibly by laser cutting for small fabrication runs.
In the case of a plate 14 of iron-nickel, the plate could in particular be made by the LIGA method, or by laser cutting.
In the case of a plate 14 of steel or titanium, the plate 14 can be hollowed for example by wire electrical discharge machining (WEDM).
The constituent parts of the mechanism are now going to be described in more detail. Some of these parts are stiff and others (in particular those called “elastic branches”) are elastically deformable, mainly in flexion. The difference between the stiff parts and the elastic parts is the stiffness thereof in the XY plane of the plate 14, which is due to the shape thereof and in particular the slenderness thereof. The slenderness can in particular be measured by the slenderness ratio (ratio of length to width of the part in question). For example, the stiff parts have a stiffness in the XY plane at least about 100 times higher than the elastic parts. Typical dimensions for the elastic links, for example the elastic branches which will be described below, include lengths included for example between 5 and 13 mm and widths included for example between 0.01 mm (10 μm) and 0.04 mm (40 μm), in particular about 0.025 mm (25 μm). Considering the width of the beams and the thickness of the plate 14, the aspect ratio of these beams in longitudinal section is included between 5 and 60.
The largest possible aspect ratio is preferred in order to limit the out of plane oscillation modes.
The plate 14 forms a fixed outer frame 15 which is fastened to a support plate 14a, for example by screws or the like (not shown) passing through holes 15a of the frame 15. The support plate 14a is securely joined to the case 2 of the timepiece 1. The frame 15 can at least partially surround the energy distribution member 10, the pallet 11 and the regulator 12.
The energy distribution member 10 can be an escapement wheel rotationally mounted for example on the support plate 14a, so as to be able to turn around a rotation axis Z0 perpendicular to the XY plane of the plate 14. The energy distribution member 10 is urged in a single direction of rotation 16 by the energy storage [device] 8.
The energy distribution member 10 has outer teeth 17.
The pallet 11 is a stiff part which can comprise a stiff body 18 extending for example parallel to the X-axis and two parallel stiff lateral arms 19, 20 extending for example parallel to the Y-axis on either side of the energy distribution member 10. The arms 19, 20 respectively comprise two stop members 21, 22 shaped like fingers projecting towards each other from the arms 19, 20 in the X-axis direction.
The pallet 11 is elastically connected to the frame 15 so as to be able to move parallel to the X-axis in a translation direction O2. Advantageously, the pallet 11 can be connected to the frame 15 by an elastic suspension, comprising for example two elastic branches 23 substantially parallel to the Y-axis. Possibly, the elastic branches 23 can be connected to the body 18 and arranged on either side of the lateral arms 19, 20 by framing these lateral arms.
The pallet 11 can additionally comprise a stiff arm 24 extending along the Y-axis towards the regulator 12, opposite from arm 20.
The pallet 11 can additionally comprise a monostable elastic member 11a, which can have the shape of an elastic tab whose free end comes to bear on the teeth 17 of the energy distribution member 10. The monostable elastic member 11a can be connected to the stiff arm 19 of the pallet 11, for example by an elastic suspension comprising two parallel elastic branches 11b extending along the Y-axis from the free end of the stiff arm 19, in extension of the stiff arm 19 to a stiff support 11c which bears the monostable elastic member 11a. The monostable elastic member 11a can extend along the Y-axis in the direction of the regulator 12, from the stiff support 11c. The monostable elastic member 11a serves such that the energy distribution member 10 transfers a precisely determined mechanical energy to the regulator, on each operating cycle of the clockwork movement 3, as explained in European patent application 14/197015 (EP 3,032,350).
The mechanism 13 further comprises a balancing member 25 which can be formed from one part with the frame 15 and which is carried on the frame 15 for oscillating parallel to the X-axis, in the translation direction O2. The balancing member 25 can for example comprise:
The balancing member 25 can also be inside the frame 15 and can be connected to the frame 15 by an elastic suspension, for example comprising two elastic branches 27 substantially parallel to the Y-axis and symmetric to the elastic branches 23 of the pallet 11. Potentially, the elastic branches 23 can be connected to the body 26 of the balancing member 25.
The pallet 11 and the balancing member 25 are each mounted on the frame 15 for oscillating in circular translation, with an oscillation amplitude in the translation direction O2 and a secondary oscillation amplitude, nonzero, perpendicular to the second translation direction. Said oscillation amplitude in the translation direction O2 is larger than the secondary oscillation amplitude of the pallet and of the balancing member, for example at least 10 times larger than the secondary oscillation amplitude of the pallet and of the balancing member.
The balancing member 25 can advantageously have a mass substantially identical to that of the pallet 11, for example included between 90% and 110% of the mass of the pallet 11. The mass of the balancing member is very close to that of the pallet but is not necessarily identical in order to allow for the fact that the stresses applied to one or the other of these members are not entirely symmetrical (for example the pallet is in contact with the energy distribution member whereas the balancing member is not).
The regulator 12 is a mechanical oscillator comprising first and second regulating members 29, 30, each forming a stiff inertial mass, and each connected to the frame 15 by an elastic suspension which is suited so that the first and second regulating members 29, 30 oscillate along the Y-axis, in a translation direction O1.
The elastic suspension is formed by the set of elastic links 31; 36, 55 which connect (directly or indirectly) the first and second regulating members 29, 30 to the frame 15. This elastic suspension has some overall stiffness, on which depends the oscillation frequency f of the first and second regulating members 29, 30.
The elastic suspension of the first and second regulating members 29, 30 can for example comprise two elastic branches 31 for each regulating member 29, 30 that extend substantially along the X-axis and are connected to the frame 15.
Each of the first and second regulating members 29, 30 is therefore mounted on the frame 15 for oscillating in circular translation, with a first oscillation amplitude in the translation direction O1 and a secondary oscillation amplitude, nonzero, perpendicular to the translation direction O1. Said oscillation amplitude in the translation direction O1 is larger than the secondary oscillation amplitude of the first and second regulating members, for example at least 10 times larger than the secondary oscillation amplitude.
In the example shown, the first and second regulating members 29, 30 can each have a C shape, with the main body 32 extending along the Y-axis between two lateral arms 33 extending towards the inside of the frame 15. The aforementioned elastic branches 31 can advantageously be connected to the free ends of the lateral arms 33, which would allow having elastic branches 31 that are long and therefore particularly flexible.
The first and second regulating members 29, 30 can be two parts symmetric about the aforementioned axis of symmetry Y0, with identical or substantially identical mass. Between them they can define a free central space 34.
The first and second regulating members 29, 30 can be connected respectively to the pallet 11 and to the balancing member 25, for example by elastic drive branches 36. Thus, the first regulating member 29 commands the movements of the pallet 11 and the second regulating member 30 commands the movements of the balancing member 25.
The elastic drive branches 36 can for example extend substantially along the X-axis. The elastic drive branches 36 can in particular be connected respectively to the free ends of the stiff arm 24 of the pallet and the stiff arm 28 of the balancing member.
Possibly, each of the first and second regulating members 29, 30 may comprise a notch 35 open along the X-axis between the main body 32 and the stiff arm 33 closest to the pallet 11 or balancing member 25, and the corresponding elastic drive branch 36 may be connected to the main body 32 at the bottom of said notch 35, which allows lengthening the elastic drive branches 36 and therefore increasing the flexibility thereof.
A stiff balancing lever 37, mounted pivoting around a central rotation center P, is arranged in the free inner space 34. The balancing lever 37 may possibly have a substantially M shape, with the central V shaped part 38 separating from the center of rotation P and two lateral arms 39.
The lateral alarms 39 can be respectively connected to the first and second regulating members 29, 30, for example by two elastic branches 40 extending substantially along the Y-axis.
The balancing lever 37 can be mounted, by an elastic suspension 43, on a stiff support 40a stiffly connected to the frame 15. The stiff support 40a can for example comprise an arm 41 extending along the axis of symmetry Y0, from the frame 15 to a head 42 which can for example extend along the X-axis by giving a T shape to the support 40a.
The elastic suspension 43 can for example comprise:
The balancing lever 37 compels the first and second regulating members 29, 30 to move symmetrically and oppositely along the translation direction O1, which, via the elastic drive branches 36, compels the pallet 11 and the balancing member 25 to move symmetrically and oppositely along the translation direction O2, as shown in
With these opposing movements, a dynamic balancing of the mechanism 13 is possible, in this way the sensitivity of the mechanism 13 to shocks, gravity and more generally to accelerations can be reduced.
The mechanism 13 further comprises a frequency adjustment device comprising a frequency adjustment member 53, with which to finely adjust the oscillation frequency of the regulator 12, in particular during mounting of the movement 3. The frequency adjustment member 53 can for example be formed from a single part in the plate 14 with the other members of the aforementioned mechanism 13.
The frequency adjustment member 53 is connected, directly or indirectly, to at least one other regulating member 29, 30 by an elastic link described as adjustment 36, 55. The frequency adjustment member 53 is furthermore adjustable in position relative to the support plate 14a and the frame 15 so as to be able to deform the elastic adjustment link 36, 55 and thus apply an adjustable elastic stress on the regulating member in question, so as to influence the overall stiffness of the elastic suspension of the regulator 12, and therefore the aforementioned frequency f.
The frequency adjustment member 53 can for example be connected to the frame 15 by two elastic branches 54 extending along the Y-axis.
In the example shown in
The second elastic part 55 may comprise at least one U-shaped part, or be constituted by a U. In this case, the elastic link 55 can comprise two branches substantially parallel to the Y-axis which are connected to each other at an end close to the frame 15, and whose free ends are connected respectively to the frequency adjustment member 53 and to the balancing member 25.
The frequency adjustment member 53 is mounted movable relative to the frame 15 and to the support plate 14a, at least parallel to the X-axis, for example by means of the aforementioned elastic branches 54. The frequency adjustment member 53 comprises a blocking device 56 suited for blocking the frequency adjustment member 53 relative to the support plate 14a, and therefore relative to the frame 15. The blocking device can include for example a screw 56 screwed into the support plate 14a around an axis 58.
More specifically, in the example considered, as shown in
Advantageously, the adjustment member 53 and the frame 15 (or the support plate 14a) comprise facing indexes 60, 61 suited for visually assessing the position of the adjustment member 53 relative to the frame 15. In the example shown, the frame 15 comprises a projection 59 comprising a rectilinear edge provided with several indexes facing the frequency adjustment member 53, and the frequency adjustment member 53 comprises a point 61 or the like facing the indexes 60.
On
The previously described mechanism operates according to the principle explained in the aforementioned European patent application 14/197015 (EP 3,032,350). In the following explanation of this operation, the concepts of top/bottom left/right are used to clarify the description in light of the orientation of the drawings from
In the situation from
The first and second regulating members 29, 30 oscillate in the translation direction O1 between the two extreme positions shown respectively in
In a semi-cycle of movement, for example when the first regulating member 29 moves from the extreme “top” position of
The pallet 11 and the balancing member 25 therefore oscillate with a frequency 2f in the translation direction O2.
The operation is the same when next moving from the position from
In the second embodiment of the invention, shown in
The pallet 11 and the regulator 12 form an advantageously monolithic mechanism 13, formed in a single plate 14 (usually flat) and for which the mobile parts are designed to move essentially in a median plane of said plate 14. The explanations about the plate 14 given relating to the first embodiment remain valid in the second embodiment.
The plate 14 comprises frame 15 which is secured to a support plate 14a, for example by screws or the like (not shown) passing through holes 15a of the support 15. The support plate 14a is securely joined to the case 2 of the timepiece 1.
The energy distribution member 10 can be an escapement wheel rotationally mounted for example on the support plate 14a, so as to be able to turn around a rotation axis Z1 perpendicular to the XY plane of the plate 14. The energy distribution member 10 is urged in a single direction of rotation 16 by the energy storage device 8.
The energy distribution member 10 has outer teeth 17.
The regulating member 118 of the regulator 12 is connected to the support 15 by an elastic suspension 119 connecting said regulating member to the support. More specifically, said regulating member 118 can have substantially an axial symmetry of order n about a central axis Z′0 orthogonal to the XY-plane and fixed relative to the support 15. By “have substantially an axial symmetry of order n,” it is understood that the regulating member 118 is essentially conformed to this symmetry, but that some parts of relatively negligible mass might not have this symmetry (for example parts serving to couple the pallet with the regulating member).
Said regulating member 118 comprises a number of stiff portions n connected together pairwise by n elastic coupling links, where n is an integer at least equal to 2.
The elastic suspension 119 has n elastic suspension links connecting respectively each stiff portion of the regulating member to the support 15.
In particular, the elastic suspension can be provided such that the regulating member 118 is substantially mobile in rotation around the central axis Z′0.
Advantageously, the number n is equal to 3; it can just the same be equal to 2 or more than 3. When the number n is 3 or more, each stiff portion of the regulating member 118 is connected to two adjacent stiff portions of the regulating member respectively by two elastic coupling links.
The regulating member 118 of the regulator 12 can have a general annular shape centered on the central axis Z′0 and comprise 3 stiff portions 120 connected pairwise between them by 3 elastic coupling links 121.
The elastic suspension 119 which connects the regulating member 118 of the regulator 12 to the support 15 comprises 3 elastic suspension links 122 respectively linking each stiff portion 120 to the support 15 such that each stiff portion 120 is mobile with a movement at least of rotation around the central axis Z′0, where the regulating member 118 has an overall movement substantially of rotation around the central axis Z′0.
Each elastic suspension link 122 advantageously comprises at least one elastic branch 123, for example one elastic branch 123. Each elastic branch 123 can possibly comprise a stiff segment 123a, for example towards the center of said elastic branch 123.
Because the elastic branches 123 deflect during the rotation of the regulating member, the stiff portions 120 of the regulating member are mobile both in rotation and in radial translation about the central axis Z′0.
The support 15 can possibly have a substantially star shape, with three branches 15b connected by a central part 15c near the axis Z′0.
The stiff portions 120 of the regulating member 118 can each comprise a part 124 with circular-arc shape centered on the central axis Z′0. The circular-arc shaped parts 124 are neighbors of each other and together form a discontinuous ring centered on the central axis Z′0.
Each elastic branch 123 can extend substantially radially relative to the central axis Z′0 and connect the circular-arc shaped part 124 of one of the stiff portions 120 to the aforementioned central portion 15c of the support 15.
The circular-arc shaped parts 124 each extend angularly between a first end 125 and a second end 126 which mutually overlap in the angular direction. For example, each first end 125 can form a first finger 125a extending towards the adjacent stiff portion 120 and each second end 126 can form a second finger 126a extending towards the adjacent stiff portion 120, where each first finger portion 125a overlaps the second finger 126a of the adjacent stiff portion 120 towards the outside.
The second end 126 of each circular-arc shape part 124 can be extended substantially radially towards the inside by a stiff arm 127 terminated by a beak 128 extending angularly beyond the second end, in the direction of the adjacent stiff portion 120.
Each elastic coupling link 121 may comprise at least one elastic coupling branch 121a (here two parallel elastic coupling branches 121a) extending substantially radially relative to the central axis Z′0 and connecting the beak 128 of each stiff portion 120 to the first end 125 of the circular-arc part 124 of the adjacent stiff portion 120.
The travel of each stiff portion 120 of the regulating member can be limited by means for limiting movement relative to the support 15, for limiting the travel, in particular angular, of the stiff portions 120 and protecting the mechanism 13 in particular in case of shock or more generally when it experiences strong accelerations.
These means for limiting movement can comprise a slit 129 laid-out in each circular-arc part 124 and extending angularly around the central axis Z′0, and the pin 130 which is rigidly connected with the support 15 (in fact, fixed to the support plate 14A) and which is arranged in the slit 129. The slits 129 are shaped according to the kinetics of the stiff portions 120 during the rotational movement of the regulating member 118. The slits 129 therefore do not have a circular shape centered on the central axis Z′0, but instead here have a spiral segment shape.
The pallet 11 and the energy distribution member 10 can be arranged inside the regulating member 118.
The pallet 11 is a stiff part which can comprise a stiff body 131 near the circular-arc part 124 of one of the stiff portions 120 of the regulating member. The pallet 11 can additionally comprise a stiff drive arm 132 which is rigidly connected with the stiff body 131 and which extends from one of said stiff bodies 131 towards one of the branches 15b of the support.
The pallet 11 is elastically connected to the support 15, so as to be able to oscillate, for example according to a substantially rotational movement about an axis Z2 perpendicular to the XY plane. The oscillations of the pallet 11 are commanded by the regulating body 118.
For that purpose, the stiff arm 127 of one of the stiff portions 120 of the regulating member can be extended inward by an additional stiff arm 133 whose free end is connected to the free end of the stiff drive arm 132 by an elastic drive branch 134.
Advantageously, the pallet 11 can be connected to the support 15 by an elastic suspension, comprising for example two elastic branches 135 for pallet suspension converging substantially towards the axis Z2. Possibly, the elastic branches 135 can connect the stiff body 131 to the free end 15d of one of the branches 15b of the support.
The pallet 11 comprises two stop members 136, 137, shaped like tabs projecting substantially towards the Z1 axis, which are suited for engaging with the energy distribution member 10.
The pallet 11 is thus commanded by said regulating member 118 for regularly and alternately blocking and releasing the energy distribution member 10 by means of stop members 136, 137, such that said energy distribution member 10 moves stepwise in the direction 16 under the urging of the energy storage device 8 in a cycle of repetitive movement, and said pallet 11 is further suited for transferring the mechanical energy to the regulating body 118 during this repetitive movement cycle, in a well-known way.
In the sample implementation, the total mass of the oscillating parts of the mechanism can be about 0.33 g and their inertia about 20.19×10−9 kg.m2; the oscillating frequency of the regulating member 118 is about 18 Hz and the rotational stiffness of the mechanism is about 2.58×10−4 Nm/rad. Such a mechanism has a very good isochronism, which leads to a very good time precision.
The mechanism 13 additionally comprises a frequency adjustment device with which to adjust the aforementioned frequency f. This frequency adjustment device comprises a stiff frequency adjustment member 153, with which to finely adjust the oscillation frequency of the regulator 12, in particular during mounting of the movement 3. The frequency adjustment member 153 can for example be formed from a single part in the plate 14 with the other members of the aforementioned mechanism 13.
The frequency adjustment member 153 is connected, directly or indirectly, to at least one of the stiff portions 120 of the regulating member 118 by an elastic link referred to as adjustment 155. The frequency adjustment member 153 is furthermore adjustable in position relative to the support plate 14a and the support 15 so as to be able to deform the elastic adjustment link 155 and thus apply an adjustable elastic stress on the regulating member 118, so as to influence the overall stiffness of the elastic suspension of the regulator 12, and therefore the aforementioned frequency f.
The frequency adjustment member 153 can have an elongated shape extending between a first end 153a and a second end 153b. The frequency adjustment member 153 can be arranged inside the regulating member 118, for example between one of the branches 15b of the support 15 and one of the aforementioned stiff arms 127. The second end 153b can possibly have a fork shape or comprise a hole for passage for an adjustment screw 156. The second end 153b can possibly be arranged facing a notched part 15e of the adjacent branch 15b of the support.
The frequency regulating member 153 can for example be connected to one of the branches 15b of the support 15 by two elastic branches 154. The elastic branches 154 may converge towards the first end 153a, which thus defines a pivoting axis Z3 of the frequency adjustment member 153 (perpendicular to the aforementioned XY plane). The notched part 15e of the branch 15b adjacent to the frequency adjustment member 153 may advantageously have an edge 15f, that is substantially circular and centered on the pivoting axis Z3, which may possibly be substantially in contact with the second end 153b of the frequency adjustment member 153 and thus contribute to guiding the frequency adjustment member 153 when the position thereof is adjusted. The notched part 15e of the branch 15b in question can possibly comprise indexes 60 such as described in the first embodiment.
In the example shown in
The elastic adjustment link 155 can connect the free end of the lever arm 153c to the regulating member 118, for example to the free end of the stiff arm 127 adjacent to the frequency adjustment member 153.
In the example shown, this elastic adjustment link 155 can comprise three elastic branches 155a, 155b, 155c, comprising a first elastic branch 155a leaving from the free end of the lever arm 153c and extending to a first elbow, the second elastic branch 155b extending from the first elbow to a second elbow and the third elastic branch 155c extending from the third elbow to the free end of the aforementioned stiff arm 127.
The frequency adjustment member 153 can be adjusted by pivoting the second end 153b thereof around the pivoting axis Z3 and then held in position by the aforementioned adjustment screw 156. The adjustment screw 156 can for example pass through a circular-arc shaped slot 161 arranged in the support plate 14a. This slot can have a substantially circular-arc shape centered on the pivoting axis Z3. The adjustment screw 156 can for example be screwed into a nut (not shown) placed under the support plate 14a. The adjustment and holding in position of the frequency adjustment member 153 could be done by any other means such as eccentric connection or other.
When it is necessary to perform a fine adjustment of the frequency f of the regulator, for example upon initial mounting of the movement 3 or after maintenance, an operator can loosen the adjustment screw 156 and adjust the position of the frequency adjustment member 153, manually or by automated means, until obtaining the exact desired frequency (measured by conventional means, notably optical).
| Number | Date | Country | Kind |
|---|---|---|---|
| 16 52134 | Mar 2016 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/055876 | 3/13/2017 | WO | 00 |
