Patent Application
20140321250
The present invention relates to the field of mechanical horology. It more particularly relates to a timepiece part including a system for correcting the seat of the escapement, aiming to reduce the influence of orientation variations of said timepiece part, on its operation. It comprises a frame bearing an energy source, a chassis comprising a first pivoting system around a first axis, using which a support is pivotably mounted inside said chassis, the first pivoting system comprising two coaxial half-arbors. An escapement is also arranged on the support.
The chassis includes a second pivoting system around a second axis substantially perpendicular to the first, using which the chassis is pivotably mounted in reference to the frame. The second pivoting system comprises two coaxial half-arbors. A half-arbor of the first pivoting system bears a wheel forming a first kinematic chain with a wheel supported by a half-arbor of the second pivoting system.
A timepiece part as described above is in particular known from application WO2009/026735. One embodiment is proposed in
The timepiece comprises a first transmission gear train 16, kinematically connected to an energy source and bringing that energy to the escapement 14, and a second reference gear train 18, connected to the stationary element of the frame. The two gear trains are arranged in parallel, such that any rotation between the supports and the frame or between the supports themselves, results in an identical rotation of the transmission and reference gear trains.
The timepiece further comprises a reverser system 20 making it possible to cause the last discs of the transmission and reference gear trains to rotate in opposite directions. Lastly, a differential correction device 22 makes it possible to cancel all of the movements of the support to bring only the energy from the energy source to the escapement. In fact, the transmission gear train 16 brings a movement corresponding to the rotation of the supports (R) and the rotation caused by the torque from the energy source (E) to a first input of the differential correction device. The reference gear train 18 also transmits a movement corresponding to the rotation of the supports (R) to the reverser system 20, the latter therefore transmitting a reverse movement (−R) to a second input of the differential correction device. The latter is arranged so as to produce the algebraic average of the first input and the second input (or (R−R+E)/2), such that, at its output, only a rotation caused by the torque from the energy source remains.
Thus, the supports bear the two gear trains, transmission 16 and reference 18, respectively, a reverser system 20 and a differential correction device 22, in addition to the escapement system. The present invention aims to reduce the number of parts supported by the supports and to reduce the volume occupied by the latter.
More specifically, the invention relates to a timepiece including:
In the timepiece according to the invention, one of the wheels supported by the second pivoting system is kinematically connected to the energy source, and the other wheel supported by that pivoting system is stationary relative to the frame. Furthermore, the two wheels supported by the first pivoting system are kinematically connected with an input of a differential arranged to transmit, at its output, the average of the rotations received at its inputs, said output being kinematically connected to the escapement.
Other details of the invention will appear more clearly upon reading the following description, done in reference to the following figures:
Only the elements related to the invention are shown in the figures. One skilled in the art will know how to adapt the technical teaching provided by this description to a clockwork movement including a frame, an energy source and a going train and motion-work to bring the energy to an escapement and display time information, respectively.
The figures therefore show a chassis 50 that is advantageously defined by a substantially annular armature in order to limit the volume it occupies in its movements, as will be seen hereinafter.
This chassis 50 comprises a first pivoting system 52 around a first axis A-A, more particularly shown in
Hereinafter, an index a refers to an element of the half-arbor 54a and an index b refers to an element of the half-arbor 54b. Each half-arbor 54a and 54b comprises a shaft 58a and 58b pivoting on two bearings 60a and 60b positioned at the ends of a tube 62a and 62b. The latter are fastened on a support 64 that will be described in more detail below. Each tube 62a or 62b receives a bearing on its outer perimeter, for example a ball bearing, whereof an inner ring 68a, 68b is fastened on the tube 62a, 62b and whereof the outer ring 70a, 70b is positioned in an opening 72a, 72b of the chassis 50. A washer 74a, 74b closes the bearing. This first pivoting system 52 makes it possible to pivot the support 64 inside the chassis 50.
Furthermore, each shaft 58a, 58b receives, at a distal end in reference to the center of the chassis 50, a wheel 76a, 76b, and at a second proximal end in reference to the center of the chassis 50, a pinion 78a, 78b.
As more particularly shown in
Each half-arbor 154a, 154b comprises a shaft 158a, 158b pivoting on two bearing blocks 160a, 160b positioned at the ends of a tube 162a, 162b, fastened in an opening 172a, 172b of the chassis 50. Each tube 162a, 162b receives, on its outer perimeter, a bearing, for example a ball bearing, whereof an inner ring 168a, 168b is fastened on the tube 162a, 162b, and whereof the outer ring 170a, 170b is positioned in a housing of the frame, not shown. A washer 174a, 174b closes the bearing. This second pivoting system makes it possible to pivot the chassis 50 relative to the frame.
Furthermore, each shaft 158a, 158b receives, at a proximal end in reference to the center of the chassis 50, a wheel 176a, 176b. We will return to the distal end of the shafts 158a and 158b later.
Each wheel 76a, 76b of the first pivoting system 52 forms a kinematic chain with a wheel 176a, 176b of the second pivoting system. There is thus a first kinematic chain between the wheels 76a and 176a of two half-arbors 54a and 154a of the first and second pivoting systems, respectively, and a second kinematic chain between the other wheels 76b and 176b of the other two half-arbors 54b and 154b.
Advantageously, these kinematic connections are respectively done by an intermediate wheel 80a, 80b mounted on the chassis 50. The intermediate wheel 80a, 80b is positioned substantially at 45° in reference to the wheels with which it meshes. Such an arrangement makes it possible for only that intermediate wheel 80a, 80b to include a toothing of a conical type, while the wheels 76a, 176a; 76b, 176b, respectively, have straight teeth. All of these wheels are planar. Such an embodiment is particularly interesting, compared to the configuration of the meshing between the wheels of the transmission and reference chains of the timepiece of the state of the art proposed in
Preferably, the drive ratios of the first kinematic chain and the second kinematic chain are identical, such that the wheels 76a and 76b supported by the two half-arbors 54a and 54b of the first pivoting system 52 are driven at the same speed by the movements of the support 64. In one advantageous configuration, the wheels 76a, 76b, 176a and 176b of the pivoting systems 52a and 52b and the intermediate wheels 80a and 80b include the same number of teeth. They also have the same diameter. Through this configuration, the wheel 76a and the pinion 78a of a first half-arbor 54a of the first pivoting system 52 face those 76b and 78b of the other half-arbor 54b of that pivoting system. Seen from the center of the chassis 50, the pinions 78a and 78b are thus driven in opposite directions of rotation, at the same absolute velocity, without, however, being kinematically connected to each other by a gear train.
Thus, the relative rotations of the support 64 along the axes A-A in reference to the chassis 50 and the relative rotations of the chassis 50 in reference to the frame, along the axis B-B, are all transmitted to the pinions 78a, 78b, either directly or through kinematic chains.
Each of these pinions 78a and 78b meshes with an input of a differential 200, whereof the axes of rotation of the discs are parallel to those of the discs of the escapement. In other words, owing to the pivoting systems 52 and 152, the differential 200 is designed to have a substantially constant orientation, typically along a substantially vertical axis. More particularly, the pinion 78a meshes with a first plate 202a provided with a contrate toothing. This first plate 202a is secured to a first sun wheel 204a meshing with a first satellite 206a pivotably mounted on a satellite carrier 208. The latter is coaxial to the first sun wheel 204a and is capable of pivoting in reference to the other elements of the differential. The satellite carrier 208 is provided with a toothing and defines the output of the differential.
In parallel, the pinion 78b meshes with a second plate 202b provided with a contrate toothing. This second plate 202b is secured to a second sun wheel 204b meshing with a second satellite 206b pivotably mounted on the satellite carrier 208. The second satellite 206b is also arranged to mesh with the first satellite 206a.
Such a differential 200 configuration allows the output wheel, i.e., the satellite carrier 208, to transmit the average of the rotations received at its inputs. In light of the directions of rotations of the pinions 78a and 78b explained above, the first plate 202a and the second plate 202b rotate in different directions. The ratios between the pinions 78a, 78b and the plates 202a and 202b are calculated so that the plates rotate at the same absolute velocity. Thus, at the output of the differential 200, the rotations due to the movements of the support 64 cancel each other out, without using a specific reverser, the proposed construction according to the invention directly producing two opposite rotations at the inputs of the differential 200.
It may be noted that the proposed configuration allows great compactness of the differential. Owing to its configuration, it may easily be housed in a cavity of the support 64. These space gains offer the possibility of improving the pivoting of the elements of the differential 200. In fact, if the first plate 202a whereof the corresponding axis is situated at the center of the differential pivots on bearing blocks 210, the second plate 202b and the satellite carrier 208 are pivoted on bearings 212 and 214, respectively, for example ball bearings, fastened in ad hoc openings of the support 64.
The axis 209a of the first plate 202a is thus pivotably mounted between two bearing blocks 210, typically formed by stones. One is driven into a bar 216 supported by the support 64, and the other is driven into a tube 218, also fastened on the support 64, typically by a screw 220 inserted into the tube.
The second plate 202b is secured to a hub 222, comprising a central opening, passed through by the axis 209b of the second plate. The axis 209b of the second plate is adjusted in that central opening and is freely passed through by the axis 209a of the first plate. The axis 209b of the second plate has a collar 224 that defines a groove with a flank of the hub 222. An inner ring 226 of the ball bearing 212 is adjusted in the groove, while an outer ring 228 of that bearing is fastened on the additional bar 230 of the support 64. The second plate 202b is thus guided in rotation from the outside of its axis 209b. The second input of the differential is thus pivoted directly on the support 64.
Furthermore, the satellite carrier 208 is provided with a central opening, inside which an outer ring 232 of the bearing 214 is fastened. An inner ring 234 is positioned in a groove defined by the support 64 and a collar 236 included by the tube 218. The satellite carrier 208 is thus pivoted directly on the support 64. The bearing 214 is slightly raised relative to the bottom of the cavity of the support 64, so that the satellite carrier 208 does not rub on it. Such a construction of the differential makes it possible to improve the working conditions of the different elements. The output obtained is very good.
One of the wheels supported by one of the half-arbors is kinematically connected to the energy source. In the proposed example, it is a pinion 178a situated at the distal end of the shaft 158a of the second pivoting system that is engaged with the going train and that therefore makes it possible to bring the torque from the energy source to one of the inputs (in this case the first plate 202a) of the differential 200. The other input of the differential 200 does not receive the torque coming from the energy source. Given that, as mentioned above, the differential 200 takes the average of the rotations received at those inputs and the rotations due to the movement of the support 64 cancel each other out, the output of the differential 200, i.e., the satellite carrier 208, therefore only transmits a rotation induced by the torque provided by the energy source.
The satellite carrier 208 is kinematically connected to the escapement, as can particularly be seen in
It may also be noted that the half-arbor 154b, i.e., the half-arbor of the second pivoting system opposite that which is connected to the energy source, includes a blocking system in reference to the frame. A square or a brake-lever 250 can be fastened on the shaft, the rotation of which is in turn blocked in the frame. The rotations of the support 64 are thus indeed transmitted to the differential.
To assist the horizontal maintenance of the escapement, the support 64 can advantageously be ballasted. It defines an unbalance situated at a lower level relative to the axes of the pivoting systems, participating in the orientation of the support 64 and the chassis 50. It will be noted that the system more generally makes it possible to preserve a constant orientation of the escapement, independently of the position of the frame, that orientation being able to be not horizontal.
Thus, the timepiece described above makes it possible to optimize the construction relative to the state of the art. Not only are the different rotational movements related to the movements of the support 64 canceled out without using a reverser system, but additionally, the construction is simplified and improved, making it possible to reduce the sizing of the chassis 50. This is in particular due to the combination of several parameters.
Arranging the differential 200 along an axis parallel to the axes of the discs of the escapement makes it possible to reduce the diameter of the chassis 50. In fact,
Furthermore, using an angle escapement also has a positive effect. This arrangement is made possible by the fact that the bar has a working surface whereof the size and free space make it possible to position the centering of the elements of the assortment relatively simply.
Furthermore, the construction of the chassis 50 and its pivoting means is also a source of improvement. In fact, the pivoting along the two axes A-A and B-B is done using a single chassis 50. The first pivoting system 52 serves as an interface between the chassis 50 and the support 64. It is positioned on the inner side of the chassis 50. The second pivoting system serves as an interface between the chassis 50 and the frame. It is positioned on the outer side of the chassis 50. The chassis 50 therefore includes two pairs of openings 72a, 72b and 172a, 172b, each pair respectively being situated on one of the axes A-A and B-B. For the axis A-A, the openings 72a, 72b are secured to the outer rings 70a, 70b of the bearings, while for the axis B-B, the openings 172a, 172b are secured to the inner rings 168, 168 of the bearings.
To facilitate the reader's understanding and the comparison between the two alternatives, the identical or similar elements use the same reference numbers. The wheels 76a and 76b respectively supported by the half-arbor 54a and by the half-arbor 54b of the first pivoting system are respectively connected to a first input and a second input of a differential 200, identically to what was described above.
Like the first alternative, the wheel 76a forms a first kinematic chain with a first wheel 176a supported by a first half-arbor 154a of the second pivoting system 152. In the proposed embodiment, the wheel 176a is connected to the energy source, as will be described below.
The wheel 76b forms a second kinematic chain with a second wheel 176b, in this case coaxial to the first half-arbor 154a of the second pivoting system 152. In the proposed embodiment, the wheel 176b is stationary relative to the frame. In other words, the two wheels 176a and 176b are positioned coaxially on the first half-arbor 154a, but are mounted freely rotating relative to one another and relative to the chassis 50, the wheel 176b being stationary relative to the frame.
Thus, on the first half-arbor 154a, there is a pinion 178a kinematically connected to the energy source and secured in rotation with the wheel 176a. It will be noted that it is possible to reverse the functions of the wheels 176a and 176b and to have the wheel 176b kinematically connected to the energy source and the wheel 176a stationary relative to the frame. In this embodiment, the second half-arbor 154b is a simple pivoting system of the chassis 50 relative to the frame.
In the example proposed in
In the two alternatives above, it is possible to provide that the wheels 76a and 76b are not driven at the same velocity, by adapting the gear ratios at the differential, i.e., by having different gear ratios between the first input and the output, on the one hand, and between the second input and the output, on the other hand, so that the movements of the chassis are indeed offset by the differential.
Thus proposed is a timepiece part whereof the operation is freed of the influence of its orientation variations, having an improved construction relative to the state of the art. It can also be noted that one of the advantages of the proposed system is that it is self-balancing. In fact, any torque induced by the transmission of energy at the kinematic chain that is connected to the energy source causes a counter-torque at the other kinematic chain. Thus, if the chassis were to be in a vertical position along the axis B-B, in which the counterweight could not balance the chassis, the self-balancing makes it possible to prevent the chassis from beginning to rotate around the axis B-B. The present description was provided solely as an illustration of the invention. In particular, regarding the intermediate wheels of the kinematic chains, it is quite possible to consider directly connecting the wheels 76a and 176a, on the one hand, and the wheels 76b and 176b, on the other hand, or on the contrary to increase the number of intermediate wheels.
| Number | Date | Country | Kind |
|---|---|---|---|
| 01918/11 | Dec 2011 | CH | national |
| 00624/12 | May 2012 | CH | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2012/074082 | 11/30/2012 | WO | 00 | 5/29/2014 |
