Abstract:
A timepiece part, includes a frame having a power source, a housing including a first pivotal movement system and a second pivotal movement system; an escapement set up on a mounting, a first kinematic linkage including a first wheel borne by a first half-shaft from the first pivotal movement system and a second wheel borne by a first half-shaft from the second pivotal movement system, and a second kinematic linkage including a first wheel borne by the second half-shaft from the first pivotal movement system and a second wheel borne by the first or second half-shaft of the second pivotal movement system. One of the wheels borne by the second pivotal movement system is kinematically linked to the power source, and the other wheel borne by the pivotal movement system is stationary relative to the frame. Both wheels borne by the first system are kinematically linked to a differential.

Description:
TECHNICAL FIELD 
     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. 
     BACKGROUND OF THE INVENTION 
     A timepiece part as described above is in particular known from application WO2009/026735. One embodiment is proposed in  FIG. 1 . More specifically, this document discloses a timepiece comprising at least two articulated supports, a first  10  being articulated relative to the frame along a first axis, the second  12  being articulated in reference to the first support along a second axis orthogonal to the first. The escapement  14  is mounted on the second support and, owing to the articulation, can preserve a substantially stable orientation, preferably substantially horizontal, independently of the position of the frame. “Horizontal orientation” indicates that the planes of the discs are horizontal, and the axes of those discs are vertical. 
     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. 
     BRIEF DESCRIPTION OF THE INVENTION 
     More specifically, the invention relates to a timepiece including:
         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 the chassis, the first pivoting system comprising first and second coaxial half-arbors, and   a second pivoting system around a second axis substantially perpendicular to the first, using which the chassis is pivotably mounted relative to the frame, the second pivoting system comprising first and second coaxial half-arbors,   
           an escapement arranged on said support,   a first kinematic chain comprising:
           a first wheel supported by the first half-arbor of the first pivoting system,   a second wheel supported by the first half-arbor of the second pivoting system, and   
           a second kinematic chain comprising:
           a first wheel supported by the second half-arbor of the first pivoting system,   a second wheel supported by the first or second half-arbor of the second pivoting system.   
               

     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other details of the invention will appear more clearly upon reading the following description, done in reference to the following figures: 
         FIG. 1  illustrates a timepiece part according to the state of the art, 
         FIG. 2  shows a three-dimensional view of a timepiece part according to the invention, 
         FIGS. 3 and 4  are cross-sectional views, along the two axes of the systems of rotation, of a timepiece part according to the invention, and 
         FIG. 5  proposes a three-dimensional view of an alternative of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     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  FIG. 3 . This first pivoting system  52  comprises two half-arbors  54   a  and  54   b , positioned coaxially along the axis A-A. The term “half-arbor” is not limiting and must be understood functionally, i.e., it is possible to consider a construction in which the half-arbors are defined by two parts of an arbor, on which the elements that will now be described pivot. 
     Hereinafter, an index a refers to an element of the half-arbor  54   a  and an index b refers to an element of the half-arbor  54   b . Each half-arbor  54   a  and  54   b  comprises a shaft  58   a  and  58   b  pivoting on two bearings  60   a  and  60   b  positioned at the ends of a tube  62   a  and  62   b . The latter are fastened on a support  64  that will be described in more detail below. Each tube  62   a  or  62   b  receives a bearing on its outer perimeter, for example a ball bearing, whereof an inner ring  68   a ,  68   b  is fastened on the tube  62   a ,  62   b  and whereof the outer ring  70   a ,  70   b  is positioned in an opening  72   a ,  72   b  of the chassis  50 . A washer  74   a ,  74   b  closes the bearing. This first pivoting system  52  makes it possible to pivot the support  64  inside the chassis  50 . 
     Furthermore, each shaft  58   a ,  58   b  receives, at a distal end in reference to the center of the chassis  50 , a wheel  76   a ,  76   b , and at a second proximal end in reference to the center of the chassis  50 , a pinion  78   a ,  78   b.    
     As more particularly shown in  FIG. 4 , the chassis  50  also includes a second pivoting system  152  around a second axis B-B, substantially perpendicular to the first axis A-A. The second pivoting system comprises two half-arbors  154   a  and  154   b , positioned coaxially along the axis B-B. The construction of the half-arbors of the second pivoting system is similar to that described above. The elements of the second pivoting system are designated by reference numbers copying the reference numbers of the first pivoting system, preceded by a 1. 
     Each half-arbor  154   a ,  154   b  comprises a shaft  158   a ,  158   b  pivoting on two bearing blocks  160   a ,  160   b  positioned at the ends of a tube  162   a ,  162   b,  fastened in an opening  172   a ,  172   b  of the chassis  50 . Each tube  162   a,    162   b  receives, on its outer perimeter, a bearing, for example a ball bearing, whereof an inner ring  168   a ,  168   b  is fastened on the tube  162   a ,  162   b , and whereof the outer ring  170   a ,  170   b  is positioned in a housing of the frame, not shown. A washer  174   a ,  174   b  closes the bearing. This second pivoting system makes it possible to pivot the chassis  50  relative to the frame. 
     Furthermore, each shaft  158   a ,  158   b  receives, at a proximal end in reference to the center of the chassis  50 , a wheel  176   a ,  176   b . We will return to the distal end of the shafts  158   a  and  158   b  later. 
     Each wheel  76   a ,  76   b  of the first pivoting system  52  forms a kinematic chain with a wheel  176   a ,  176   b  of the second pivoting system. There is thus a first kinematic chain between the wheels  76   a  and  176   a  of two half-arbors  54   a  and  154   a  of the first and second pivoting systems, respectively, and a second kinematic chain between the other wheels  76   b  and  176   b  of the other two half-arbors  54   b  and  154   b.    
     Advantageously, these kinematic connections are respectively done by an intermediate wheel  80   a ,  80   b  mounted on the chassis  50 . The intermediate wheel  80   a ,  80   b  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  80   a ,  80   b  to include a toothing of a conical type, while the wheels  76   a ,  176   a;    76   b ,  176   b , 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  FIG. 1 . 
     Preferably, the drive ratios of the first kinematic chain and the second kinematic chain are identical, such that the wheels  76   a  and  76   b  supported by the two half-arbors  54   a  and  54   b  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  76   a ,  76   b ,  176   a  and  176   b  of the pivoting systems  52   a  and  52   b  and the intermediate wheels  80   a  and  80   b  include the same number of teeth. They also have the same diameter. Through this configuration, the wheel  76   a  and the pinion  78   a  of a first half-arbor  54   a  of the first pivoting system  52  face those  76   b  and  78   b  of the other half-arbor  54   b  of that pivoting system. Seen from the center of the chassis  50 , the pinions  78   a  and  78   b  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  78   a ,  78   b,  either directly or through kinematic chains. 
     Each of these pinions  78   a  and  78   b  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  78   a  meshes with a first plate  202   a  provided with a contrate toothing. This first plate  202   a  is secured to a first sun wheel  204   a  meshing with a first satellite  206   a  pivotably mounted on a satellite carrier  208 . The latter is coaxial to the first sun wheel  204   a  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  78   b  meshes with a second plate  202   b  provided with a contrate toothing. This second plate  202   b  is secured to a second sun wheel  204   b  meshing with a second satellite  206   b  pivotably mounted on the satellite carrier  208 . The second satellite  206   b  is also arranged to mesh with the first satellite  206   a.    
     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  78   a  and  78   b  explained above, the first plate  202   a  and the second plate  202   b  rotate in different directions. The ratios between the pinions  78   a ,  78   b  and the plates  202   a  and  202   b  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  202   a  whereof the corresponding axis is situated at the center of the differential pivots on bearing blocks  210 , the second plate  202   b  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  209   a  of the first plate  202   a  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  202   b  is secured to a hub  222 , comprising a central opening, passed through by the axis  209   b  of the second plate. The axis  209   b  of the second plate is adjusted in that central opening and is freely passed through by the axis  209   a  of the first plate. The axis  209   b  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  202   b  is thus guided in rotation from the outside of its axis  209   b . 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  178   a  situated at the distal end of the shaft  158   a  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  202   a ) 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  FIG. 4 , using a shaft  240 , provided on the one hand with an escapement pinion  242  meshing with the satellite carrier  208  and receiving the escapement wheel  244  on the other hand. The shaft  240  passes through the support  64 , such that the adjusting organ  246  and the pallet  248  are situated on the upper side of the bridge and are situated at the periphery of the chassis so as to be visible by a user. To improve the compactness of the system, the escapement is of the angle type, i.e., the axes of the adjusting organ  246 , the palette and the escapement wheel are not aligned. This makes it possible to bring the axis of the adjusting organ and that of the escapement wheel closer together. 
     It may also be noted that the half-arbor  154   b , 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,  FIG. 1  shows that the axis of the differential was previously perpendicular to the axes of the discs of the escapement. 
     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  72   a ,  72   b  and  172   a ,  172   b , each pair respectively being situated on one of the axes A-A and B-B. For the axis A-A, the openings  72   a ,  72   b  are secured to the outer rings  70   a ,  70   b  of the bearings, while for the axis B-B, the openings  172   a ,  172   b  are secured to the inner rings  168 ,  168  of the bearings. 
       FIG. 5  proposes an alternative of a timepiece part according to the invention. To facilitate the reader&#39;s understanding and the comparison between the two alternatives, the identical or similar elements use the same reference numbers. The wheels  76   a  and  76   b  respectively supported by the half-arbor  54   a  and by the half-arbor  54   b  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  76   a  forms a first kinematic chain with a first wheel  176   a  supported by a first half-arbor  154   a  of the second pivoting system  152 . In the proposed embodiment, the wheel  176   a  is connected to the energy source, as will be described below. 
     The wheel  76   b  forms a second kinematic chain with a second wheel  176   b , in this case coaxial to the first half-arbor  154   a  of the second pivoting system  152 . In the proposed embodiment, the wheel  176   b  is stationary relative to the frame. In other words, the two wheels  176   a  and  176   b  are positioned coaxially on the first half-arbor  154   a , but are mounted freely rotating relative to one another and relative to the chassis  50 , the wheel  176   b  being stationary relative to the frame. 
     Thus, on the first half-arbor  154   a , there is a pinion  178   a  kinematically connected to the energy source and secured in rotation with the wheel  176   a . It will be noted that it is possible to reverse the functions of the wheels  176   a  and  176   b  and to have the wheel  176   b  kinematically connected to the energy source and the wheel  176   a  stationary relative to the frame. In this embodiment, the second half-arbor  154   b  is a simple pivoting system of the chassis  50  relative to the frame. 
     In the example proposed in  FIG. 5  and non-limitingly, the wheels  176   a  and  176   b  are positioned on either side of the wall of the chassis  50 . According to a configuration similar to that which was described above, the wheel  176   a  meshes with an intermediate wheel  80   a , engaged with the wheel  76   a , while the wheel  176   b  meshes with an intermediate wheel  80   b,  engaged with the wheel  76   b . If applicable, the chassis  50  is arranged so as to leave the gear of the discs of the kinematic chains free. This makes this alternative a bit less compact than the first. It will be noted again that, in the proposed example, the wheels  176   a  and  176   b  have different sizes. However, preferably, the drive ratios of the wheels  76   a  and  76   b  supported by the two half-arbors of the first pivoting system  52  are identical, such that they are driven at the same absolute velocity by the movements of the support  64 . It is also possible to provide that the wheels  76   a ,  76   b  and  176   a ,  176   b  of the first pivoting system  52  and the second pivoting system  152  and the intermediate wheels  80   a ,  80   b  include the same number of teeth. 
     In the two alternatives above, it is possible to provide that the wheels  76   a  and  76   b  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  76   a  and  176   a , on the one hand, and the wheels  76   b  and  176   b , on the other hand, or on the contrary to increase the number of intermediate wheels.