Patent Publication Number: US-11048210-B2

Title: Watch movement including a multiaxial tourbillon

Description:
This application claims priority from European Patent Application No. 17187096.7 filed on Aug. 21, 2017, the entire disclosure of which is hereby incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a multiaxial tourbillon, that is to say at least biaxial, including a first cage, commonly referred to as an external cage, mounted in a pivoting manner on two fixed bearings. 
     BACKGROUND TO THE INVENTION 
     Tourbillons, also known as “rotating cages”, added to escapement mechanisms to improve the precision of mechanical watches by counteracting the disturbances of the isochronism of the balance wheel due to terrestrial gravity, are known in watchmaking. 
     Good&#39;s bi-axial tourbillon, described in detail in “Alte Uhren” 4/79 and commonly referred to as the double tourbillon, has been known since 1978. This type of tourbillon includes two nested cages. A first cage, referred to as the external cage, is rotatably mounted in relation to a frame of the movement, supported on both sides by a first and a second bearing of the frame. A second cage is housed in the interior of the first cage and is rotatably mounted in relation to the external cage. The second cage pivots by means of a staff which extends across the external cage and which is supported by the external cage. The staff is constrained to rotate with a pinion, said pinion being fixed on one extremity of the staff that is present on the exterior of the external cage. The pinion is in engagement with a wheel, fixed in relation to the frame, of which the axis coincides with the axis of rotation of the external cage. Rotation of the second cage thus results in rotation of the pinion and, in so doing, its displacement along the toothing of the fixed wheel. This displacement induces rotation of the staff in the axis of rotation of the external cage and consequently rotation of the external cage. 
     The rotations of the external cage are permitted by the cooperation between pivots of the external cage and watch jewels pressed into the bearings. The watch jewels take the form of drilled discs, making it possible to receive and maintain the pivots axially. It will be appreciated that moving the watch jewels apart or together in relation to each other permits the movement of the external cage to be regulated, and that displacing the two watch jewels jointly on the axis of rotation of the external cage makes it possible to regulate the gearing clearance, that is to say the centre distance between the pinion and the fixed wheel, in a very precise manner. 
     At the present time, when it is wished to regulate the movement of the external cage and/or the gearing clearance between the pinion and the fixed wheel, the external cage must first be disassembled from the bearings on which it rests. More specifically, the pivots of the external cage must be removed from the watch jewels. The watch jewels are then accessible and may thus be displaced in relation to the bearings in the axis of rotation of the external cage, conventionally by means of a jewelling press. Once the jewels are positioned correctly, the pivots of the external cage are replaced in the watch jewels. Naturally, it will be appreciated that this procedure is laborious. 
     SUMMARY OF THE INVENTION 
     The aim of the present invention is to address the previously mentioned shortcoming by proposing a watch movement in which the movement of the external cage and/or the gearing clearance between the pinion and the fixed wheel is adjustable in a simple manner without being obliged to disassemble the tourbillon. 
     To this end, the invention proposes a watch movement. 
     It is possible to displace the watch jewels or the pivots by means of the translational elements and, in so doing, to regulate the gap between the two jewels and/or the position of the cage on its axis of rotation, and consequently the movement of the external cage and/or the gearing clearance between the pinion and the fixed wheel. 
     Two embodiments are thus conceivable. 
     It will be appreciated that the movement of the external cage and the gearing clearance between the pinion and the fixed wheel may be regulated as follows: the movement of the external cage is regulated by displacing the watch jewels one in relation to the other, whereas the gearing clearance is regulated by displacing the watch jewels simultaneously so as to displace them in the same direction while preserving the same gap between them. 
     Other advantageous variants of the invention, which may be considered alone or according to all the technically possible combinations, are defined. 
    
    
     
       SUMMARY DESCRIPTION OF THE DRAWINGS 
       Other features and advantages will be appreciated clearly from the description that is given below, for information purposes and in no way restrictive, with reference to the accompanying drawings, in which: 
         FIG. 1  depicts a biaxial tourbillon mounted in a pivotable manner between two bearings according to a first embodiment of the invention 
         FIG. 2  depicts the tourbillon in  FIG. 1 , mounted in a pivotable manner between the two bearings according to a second embodiment of the invention 
         FIG. 3  depicts the tourbillon in  FIG. 1 , mounted in a pivotable manner between the two bearings according to a third embodiment of the invention 
         FIG. 4  depicts the tourbillon in  FIG. 1 , mounted in a pivotable manner between the two bearings according to a fourth embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIGS. 1 to 4  show a tourbillon  40  supported on both sides by bearings  20 ,  30  of a frame  10  of a watch movement according to the invention. 
     The tourbillon  40  illustrated here includes two concentric cages, a first cage known as the external cage  41  and a second cage known as the internal cage  42 . The internal cage  42  contains among other things a balance wheel  50 , a spring, a pallet and an escape wheel  51 . The internal cage  42  is mounted in a pivoting manner on the external cage  41  along an axis of rotation A 2 . The tourbillon  40  thus includes a staff  43  that is constrained to rotate with the internal cage  42  and extends across the external cage  41  along the second axis of rotation A 2 . The staff  43  includes two extremities, said two extremities being supported by two watch jewels positioned on two opposing walls of the external cage  41 . One of the extremities passes through the watch jewel which supports it and thus includes an end zone which extends to the exterior of the external cage  41 . 
     A pinion  60 , commonly referred to as the second pinion, is mounted on this end zone so as to be constrained to rotate with the staff  43 . The second pinion  60  includes a toothing  61  in engagement with a toothing  71  of a wheel  70 , fixed in relation to the frame  10 , commonly referred to as the third fixed wheel. The third fixed wheel  70  is mounted concentrically with the first bearing  20 , and its axis extends in the axis of rotation A 1  of the external cage  41 , said axis of rotation A 1  being perpendicular to the axis of rotation A 2  of the internal cage  42 , or inclined at an angle of between  30  and 150 degrees in relation to the axis of rotation A 2  of the internal cage  42 . 
     Rotation of the internal cage  42 , equivalent to rotation of the staff  43 , thus results in rotation of the second pinion  60 , which results in rotation of the external cage  41  by means of the displacement of the second pinion  60  in the toothing  71  of the third wheel  70 . 
     The external cage  41  includes a first pivot  44  supported by a first watch jewel  52  and a second pivot  45  supported by a second watch jewel  53 . These pivots  44 ,  45  are positioned on the axis of rotation A 1  of the external cage  41  and are secured to opposing walls of the external cage  41 . The first pivot  44 , and respectively the second pivot  45 , includes an extremity  46 , and respectively an extremity  47 , passing through the first watch jewel  52 , and respectively the second watch jewel  53 , in the axis of rotation A 1  of the external cage  41 . The watch jewels are in fact drilled at their centre, in a conventional manner, so as to receive the extremity of a pivot. 
     In the embodiment in  FIG. 1 , the first watch jewel  52  is itself supported by a first translational element  80  housed in a first orifice  21  of the first bearing  20 . The first watch jewel  52  is integral with the first translational element  80 . As for the second watch jewel  53 , this is supported by a second translational element  90  housed in a second orifice  31  of the second bearing  30 . The second watch jewel  53  is integral with the second translational element  90 . 
     The orifices  21 ,  31 , and a fortiori the translational elements  80 ,  90  housed in said orifices  21 ,  31 , extend in the axis of rotation A 1  of the external cage  41 , on both sides of the external cage  41 . Each translational element  80 ,  90  thus includes a first extremity on the side of the external cage  41 , facing one of the pivots  44 ,  45 . The first watch jewel  52  is maintained at the level of the extremity of the first translational element  80  on the side of the external cage  41 , whereas the second watch jewel  53  is maintained at the level of the extremity of the second translational element  90  on the side of the external cage  41 . The translational elements  80 ,  90  are hollow, for example, and the watch jewels  52 ,  53  are housed in these cavities. Naturally, the axis of the watch jewels  52 ,  53  coincides with the axis of rotation A 1  of the external cage  41 , the axis of the translational elements  80 ,  90  and the axis of the pivots  44 ,  45 . It will be appreciated that displacing the translational elements  80 ,  90  makes it possible to displace the watch jewels  52 ,  53 , the watch jewels being integral with the translational elements. 
     Depicted in  FIG. 4  is an alternative embodiment in which the watch jewels  52 ,  53  are not integral with the translational elements  80 ,  90 , but are integral with the frame  10 . More specifically, the first watch jewel  52  is integral with the first bearing  20 , and the second watch jewel  53  is integral with the second bearing  30 . Furthermore, the first translational element  80  rests against the extremity  46  of the first pivot  44 , and the second translational element  90  rests against the extremity  47  of the second pivot  45 . It will therefore be appreciated that displacing the translational elements  80 ,  90  makes it possible to displace the pivots  44 ,  45  relative to the watch jewels  52 ,  53 . 
     In the embodiment in  FIG. 1 , as in that of  FIG. 4 , each translational element  80 ,  90  includes actuating means  82 ,  92  at its extremity opposite that on the side of the external cage  41 . The translational elements  80 ,  90  may be displaced by cooperation between a tool and the actuating means  82 ,  92 . The actuating means  82 ,  92  are accessible from the exterior via the orifices  21 ,  31 . The two translational elements  80 ,  90  may thus be displaced in the axis of rotation A 1  of the external cage  41  by means of the actuating means  82 ,  92 . 
     Advantageously, the first translational element  80  and the second translational element  90  are two sleeves that are threaded at least in part. In the depicted example, each of these sleeves includes a threaded cylindrical portion  81 ,  91  and a non-threaded cylindrical portion. The threaded portion  81 ,  91  has a diameter smaller than the diameter of the non-threaded portion. Naturally, since it receives one of the translational elements, each orifice  21 ,  31  includes a tapped cylindrical portion  22 ,  32  of the same diameter as the threaded portions  81 ,  91 , and a non-threaded cylindrical portion of the same diameter as the non-threaded portions. When the translational elements  80 ,  90  are elements that are threaded at least in part, more particularly sleeves, the actuating means  82 ,  92  are typically a slot into which a screwdriver may be inserted in order to impart a helicoidal movement to the translational elements  80 ,  90 . 
     Furthermore, it is advantageous to provide the movement with a repositioning element. The presence of a repositioning element is optional. The repositioning element makes it possible to ensure that the external cage remains in or returns immediately to its initial position when it is subjected to a shock. 
     In an embodiment depicted in  FIG. 2  and constituting an improvement of the embodiment in  FIG. 1 , the repositioning element is a magnet  100  housed in a cavity of the second translational element  90  and is therefore integral with the second translational element  91 . The magnet  100  is maintained against the second watch jewel  53  and, more specifically, on the side of the second watch jewel  53  which is opposite the side where the external cage  41  is present. As mentioned previously, the second watch jewel  53  is drilled at its centre so as to receive the extremity  47  of the second pivot  45 , the drilling extending in the axis of rotation A 1  of the external cage  41 , between the face of the second watch jewel  53  that is present on the side of the external cage  41 , and the opposing face. The magnet  100  is thus in contact with, or at least in close proximity to, said extremity  47  of the second pivot  45 . By selecting a material adapted for the second pivot  45 , for example iron, a force of attraction is present between the magnet  100  and the second pivot  45 . 
     In  FIG. 2 , the magnet is depicted in combination with the embodiment in  FIG. 1 , although it will be appreciated that it could have been combined with the embodiment in  FIG. 4 . In the embodiment in  FIG. 4 , it would be sufficient to create a cavity in the second translational element  90 , said cavity discharging at the level of the extremity  47  of the second pivot  45 , and to position the magnet  100  in this cavity so that the magnet is in contact with the extremity  47 . 
     If the movement is subjected to a shock causing the external cage  41  to move away from the second bearing  30 , the magnet  100  ensures that the second pivot  45 , and a fortiori the external cage  41 , resumes its initial position. In more general terms, the addition of a magnetic element in proximity to or in contact with one of the pivots  44 ,  45  of the external cage  41  makes it possible to maintain said pivot in, or to return it into, forced contact against the watch jewel  52 ,  53  which supports said pivot  44 ,  45 . This forced contact ensures an invariable position of the external cage  41  and, in the same way, a uniform gearing centre distance between the pinion  60  and the fixed wheel  70 . Conventionally, the gearing centre distance between the pinion and the fixed wheel must be accurate to within 0.02 millimetres, and the movement of an external tourbillon cage is in the order of 0.05 millimetres at a maximum; it will be appreciated, therefore, that it is advantageous to force the contact of one of the pivots against its watch jewel. 
     In the embodiment depicted in  FIG. 3 , the repositioning element is an assembly consisting of a spring  101  and a piston  102 , on this occasion installed on the side of the first translational element  80 . It will be noted that the actuating means  82  of the first translational element  80  are not then accessible, since the spring  101  and the piston  102  block the access to said actuating means  82 , and since the first orifice  21  is not transcurrent. Thus, only the second translational element  90  may be displaced via the access to the actuating elements  92  through the second orifice  31 . 
     The axis of the piston  102  passes through the first translational element  80  in the axis of rotation A 1  of the external cage  41  and rests against the extremity  46  of the first pivot  44 . The head of the piston  102 , on the exterior of the first translational element  80 , rests against the spring  101 , which also extends in the axis of rotation A 1  of the external cage  41 . The spring  101  is housed in the first orifice  21  of the first bearing  20 , said first orifice  21  also containing the first translational element  80 . As mentioned previously, the first orifice  21  is not transcurrent: at its extremity opposite the piston  102 , the spring  101  may thus push against a wall of the first orifice  21 . When the movement is subjected to a shock causing the external cage  41  to move away from the second bearing  20 , the first pivot  44  exerts a pressure against the piston  102 , feeding back at the level of the head of the piston onto the spring  101  and compressing said spring  101 . By seeking to return to its initial position, the spring  101  displaces the piston  102  in the direction of the external cage  41 , the axis of the piston  102  then exerting a pressure against the first pivot  44 , with the result that the external cage  41  resumes its initial position. 
     In  FIG. 3 , it is depicted that the first translational element  80  is of the same type as that illustrated in  FIG. 1 , although there is naturally nothing to prevent it from being of the same type as that illustrated in  FIG. 4 . It would be sufficient to provide the first translational element  80  with a cavity passing through it from one side to the other, in order to insert the axis of the piston  102  at that point. Furthermore, there is also nothing to prevent the second translational element  90  from being of the same type as that illustrated in  FIG. 4 . 
     Of course, the present invention is not restricted to the illustrated example, but lends itself to different variants and modifications which will be evident to a person skilled in the art. In particular, the tourbillon could comprise more than two cages, the invention concerning above all the attachment of the external cage. 
     
       
         
           
               
             
               
                   
               
               
                 List of Reference Designations 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 10 
                 frame 
               
               
                 20 
                 first bearing 
               
               
                 21 
                 first orifice 
               
               
                 22 
                 tapping 
               
               
                 30 
                 second bearing 
               
               
                 31 
                 second orifice 
               
               
                 32 
                 tapping 
               
               
                 40 
                 tourbillon 
               
               
                 41 
                 external cage 
               
               
                 42 
                 internal cage 
               
               
                 43 
                 staff 
               
               
                 44 
                 first pivot 
               
               
                 45 
                 second pivot 
               
               
                 50 
                 balance wheel 
               
               
                 51 
                 escape wheel 
               
               
                 52 
                 first watch jewel 
               
               
                 53 
                 second watch jewel 
               
               
                 60 
                 pinion 
               
               
                 61 
                 toothing 
               
               
                 70 
                 fixed wheel 
               
               
                 71 
                 toothing 
               
               
                 80 
                 first translational element 
               
               
                 81 
                 thread 
               
               
                 82 
                 actuating means 
               
               
                 90 
                 second translational element 
               
               
                 91 
                 thread 
               
               
                 92 
                 actuating means 
               
               
                 100 
                 magnet 
               
               
                 101 
                 spring 
               
               
                 102 
                 piston