Abstract:
A shock-absorber bearing for a staff of a moving part of a timepiece, the bearing including: a support including a housing configured to receive a pivot module configured to cooperate with the staff; an elastic mechanism configured to exert at least one axial force on the pivot module to retain the pivot module in its housing, the pivot module and the housing having a geometry of revolution defined to have freedom of angular orientation, one relative to the other; and a fixing mechanism for fixing the elastic mechanism.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a National Phase Application in the United States of International Patent Application PCT/EP2013/062802 filed Jun. 19, 2013 which claims priority on European Patent application 12173044.4 filed Jun. 21, 2012. The entire disclosures of each of which are hereby incorporated herein by reference. 
     The present invention relates to a shock-proof system for a staff of a moving part of a timepiece. The staff comprises a small rod, comprising a support, said support being provided with a housing which is intended to receive a pivot system into which the small rod is inserted. The shock-proof system comprises furthermore elastic means designed to exert at least one axial force on said pivot system. 
     The technical field of the invention is the technical field of precision engineering. 
     TECHNOLOGICAL BACKGROUND 
     The present invention relates to bearings for timepieces, more particularly of the type allowing shocks to be absorbed. The constructors of mechanical watches have, for a long time, been designing numerous devices which allow a staff to absorb the energy resulting from a shock, in particular a lateral shock, by abutment against a wall of the hole of the base block which it traverses, whilst allowing a momentary displacement of the small rod before it is returned to its lock position under the action of a spring. 
       FIGS. 1 and 2  illustrate a device termed inverted double cone which is currently used in timepieces found on the market. 
     A support  1 , the base of which comprises a hole  2  for the passage of the balance staff  3  ended by a small rod  3   a , makes it possible to position a jewelled bearing  20  in which there are immobilised a pierced stone  4  traversed by the small rod  3   a  and a counter-pivot stone  5 . The jewelled bearing  20  is retained in a housing  6  of the support  1  by a spring  10  which, in this example, comprises radial extensions  9  which compress the counter-pivot stone  5 . The support  1  is a part of revolution comprising a circular rim  11 . This rim  11  is interrupted at two places which are diametrically opposite by an opening  10  so as to create two semi-circular rims  11   a ,  11   b . The opening  12  is provided in part in the two semi-circular rims  11   a ,  11   b  so as to produce two returns  13 . The jewelled bearing  20  is retained in a housing  6  of the support  1  by elastic means, such as a spring  10 , which comprises, in this example, radial extensions  9  which compress the counter-pivot stone  5 . The spring  10  is of the axial type and has the shape of a lyre designed to be supported under the returns of the semi-circular rims  11   a ,  11   b . The housing  6  comprises two bearing surfaces  7 ,  7   a  in the form of inverted cones on which complementary bearing surfaces  8 ,  8   a  of the jewelled bearing  20  are supported, said bearing surfaces requiring to be produced with very great precision. In the case of axial shock, the pierced stone  4 , the counter-pivot stone  5  and the balance staff are displaced and the spring  10  acts alone to return the balance staff  3  into its initial position. The spring  10  is dimensioned to have a displacement limit so that, beyond this limit, the balance staff  3  comes into contact with stops  14  making it possible for said staff  3  to absorb the shock, which the small rods  3   a  of the staff  3  cannot do without the risk of breaking. In the case of lateral shock, i.e. when the end of the small rod unbalances the jewelled bearing  20  out of its lock plane, the spring  10  cooperates with the complementary inclined planes  7 ,  7   a ;  8 ,  8   a  in order to re-centre the jewelled bearing  20 . Such bearings have been sold for example under the trademark Incabloc®. These springs can be produced in chromium-cobalt alloy or brass and are manufactured by traditional cutting means. 
     Now, a disadvantage of these shock-absorber systems is that their assembly is not easy. In fact some parts, such as the support  1  and the spring  10 , must be orientated and manipulated in a certain manner during the assembly operation in order that the assembly can take place. Hence, the assembly of the shock-absorber system begins by being provided with a support, then a jewelled bearing with these stones. The latter is placed in the housing of the support. Then a spring of the axial type is provided, which has the shape of a lyre. The latter is manipulated so that it can be supported under the returns of the semi-circular rims  11   a ,  11   b  of the support. 
     Consequently, positioning the spring and fixing it to the support requires a specific manipulation. For this reason, shock-absorber systems must be assembled in part manually because a robot cannot produce such a complex manipulation. 
     Furthermore, the current shock-absorber systems are assembled in part manually and not by a robot because human beings are capable of knowing immediately the orientation in which the parts of the shock-absorber system must be placed relative to each other. In fact whatever the shape of the parts, human beings are able to know immediately how they must manipulate these parts in order to assembly them. Now, even if a robot can distinguish the orientation of one piece relative to another, this requires a more complex and more expensive robot whilst requiring more time. This reduces consequently the manufacturing output. 
     Hence, total automation of the assembly is not possible and the assembly process of the shock-absorber systems is therefore more expensive. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to remedy the disadvantages of prior art by proposing to provide a shock-absorber system, the assembly of which can be automated. 
     To this end, the invention relates to a shock-absorber bearing for a staff of a moving part of a timepiece, said bearing comprising a support provided with a housing which is intended to receive a pivot module designed to cooperate with said staff, said bearing comprising furthermore elastic means designed to exert at least one axial force on said pivot module in order to retain said pivot module in its housing, the pivot module and the housing having a geometry of revolution which is defined so as to have freedom of angular orientation, one relative to the other, said bearing comprising furthermore fixing means for fixing the elastic means to the support, characterised in that furthermore at least the elastic means have a geometry of revolution which is defined so as to have freedom of angular orientation relative to the pivot module and to the housing and in that said fixing means are designed to fix the elastic means to the support whatever the angular orientation of the elastic means relative to the pivot module and to the housing. 
     A first advantage of the present invention is to allow simplification of the assembly of a shock-absorber system allowing automation of said process. In fact, it means that the support, its housing, the pivot module and the elastic means are configured to be angularly free relative to each other. This characteristic makes it possible not to need to worry about the angular position of one element relative to another so that a robot can assemble the shock-absorber system. 
     Advantageous embodiments of the invention are the subject of the dependent claims. 
     In a first advantageous embodiment, the support, the housing, the pivot module and the elastic means each have a defined geometry so as to have freedom of angular orientation relative to each other. 
     In a second advantageous embodiment, the fixing means are a material linkage between said support and said elastic means. 
     In a third advantageous embodiment, the fixing means comprise a cap which is fixed to said support in order to place said elastic means against said support. 
     In another advantageous embodiment, the fixing means comprise at least two fins disposed on the support and extending parallel to the central axis of said support, said at least two fins being able to be folded down in order to squeeze said elastic means. 
     In another advantageous embodiment, the fixing means comprise a plurality of fins which are disposed in a circle and distributed regularly. 
     In another advantageous embodiment, the elastic means comprise an annular spring which has at least one internal radial extension extending towards the centre of said annular spring. 
     In another advantageous embodiment, said annular spring comprises three internal radial extensions. 
     To this end, the invention likewise relates to a clock movement comprising a bottom plate and at least one bridge, said bottom plate comprising an orifice, characterised in that, into said orifice of said bottom plate, a shock-absorber bearing according to the invention is inserted. 
     In an advantageous embodiment, said at least one bridge comprises an orifice, characterised in that, into said orifice of said at least one bridge, a shock-absorber bearing according to the invention is inserted. 
     In another advantageous embodiment, the support of the shock-absorber bearing and said bottom plate are monobloc. 
     In another advantageous embodiment, the support of the shock-absorber bearing and said at least one bridge are monobloc. 
     To this end, the invention relates likewise to a timepiece comprising a width closed by a casing and a base, characterised in that said timepiece comprises a clock movement according to the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The aims, advantages and features of the shock-proof system according to the present invention will appear more clearly in the following detailed description of at least one embodiment of the invention which is given solely by way of non-limiting example and illustrated by the annexed drawings in which: 
         FIGS. 1 and 2 , already cited, make it possible to represent schematically a shock-absorber system of a timepiece according to prior art; 
         FIG. 3  represents schematically a shock-absorber system of the timepiece according to the invention; 
         FIGS. 4 a  and 4 b    represent a profile view of the shock-absorber system of the timepiece according to the invention; 
         FIG. 5  represents schematically a view from above of a spring for the shock-absorber system of the timepiece according to the invention; 
         FIG. 6  represents an exploded profile view of the shock-absorber system of the timepiece according to the invention; 
         FIGS. 7 and 8  represent various solutions for fixing the spring for the shock-absorber system of the timepiece according to the invention; 
         FIG. 9  represents schematically a first variant of the shock-absorber of the timepiece according to the invention; and 
         FIG. 10  represents schematically a second variant of the shock absorber of the timepiece according to the invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention arises from the general inventive idea which consists of acquiring a simple non-dismantlable shock-absorber bearing which is easy to assemble. This shock-absorber system is designed to be mounted on a bottom plate and/or on at least one bridge of a clock movement. The clock movement is placed in a timepiece comprising a width closed by a base and a crystal. 
     In  FIGS. 3, 4   a  and  4   b , a shock-absorber bearing  100  or shock-proof system according to a first embodiment is represented. This shock-proof system  100  is mounted in a base element of a timepiece movement. In particular, the bottom plate or the bridges  600  of the movement are the base element in which the shock-proof system  100  according to the invention is placed. This shock-proof system  100  comprises a support  200 . This support  200  has the shape of a base  201 , provided with a hole  202 , from which a peripheral rim  203  extends. The latter has an external flank  204 , an internal flank  205  and a top  203   a . This rim  203  makes it possible to define a housing  206  into which a pivot module  400  is inserted. A standard pivot module  400  comprises a jewelled bearing  401 , i.e. a part which has a circular central orifice, an external wall and an internal wall. In the central orifice, a pierced stone  402  is inserted, the diameter of which corresponds to that of the central orifice. The internal wall comprises a shoulder so that a counter-pivot stone  403  can be fixed. The pivot module  400  is then placed in the housing  206  of the support  200  and cooperates with the small rod of a staff. 
     The shock-proof system  100  comprises furthermore elastic means  300  which are designed to cooperate with the pivot module  400  so as to absorb shocks and to return it into its lock position when the stresses associated with the shocks subside. The elastic means  300  are fixed on the support  200 . Preferably, the elastic means  300  are likewise placed on the pivot module  400 . The shock-proof system  100  is then inserted into an orifice of the bottom plate or into one of the bridges of the movement. 
     Advantageously according to the invention, at least the housing  206 , the pivot module  400  and the elastic means  300  are produced/designed so that the various parts are angularly free relative to each other. There is understood by this that the various parts which make up the shock-absorber system  100 , such as at least the housing  206 , the pivot module  400  and the elastic means  300 , are assembled one in the other without a particular manipulation being necessary. Thus no rotation or manipulation or torsion takes place during assembly. For preference, at least the housing  206 , the pivot module  400  and the elastic means  300  are parts of revolution, i.e. having a general circular shape. This circular shape makes it possible to adapt to any support shapes  200 . Effectively, the circular shape, without orientation, of the housing  206 , of the pivot module  400  and of the elastic means  300  makes it possible to have a support  200  of any shape which, during assembly, will be positioned in any manner without that having any impact on the assembly process of the shock-absorber bearing  100 . 
     In a first embodiment which can be seen in  FIG. 3 , the support  200 , the housing  206 , the pivot module  400  and the elastic means  300  are parts of revolution, i.e. having a circular shape. 
     The elastic means  300  have, for example, the shape of an annular spring  301 . This annular spring  301  is of the flat type, i.e. it is formed from a circular metallic strip which has a greater width than thickness. In order to place said pivot module  400  in the housing  206  of the support  200 , the annular spring  301  comprises internal radial extensions  302  which are disposed between the annular portions  303 . These internal radial extensions  302  are formed by the strip which forms the ring  301  which is curved back towards the inside of the ring  301 . These internal radial extensions  302  are preferably distributed regularly over the circumference of the flat ring  301  so that the annular spring  301  can act homogeneously as can be seen in  FIG. 5 . It is therefore understood that the annular spring  301  can be orientated in any manner relative to the support  200 . 
     This configuration of the parts of the shock-absorber bearing  100  according to the invention makes it possible to facilitate assembly. In fact, if the parts have an orientation relative to each other, it is necessary to manipulate them so that the assembly can take place. For example, in order to fit together two triangular geometric Figures one in the other, it is necessary that each of the sides is parallel, an orientation is therefore necessary. 
     Now, when producing the support  200 , the housing  206 , the pivot module  400  and the elastic means  300  so that the various parts are angularly free relative to each other, it is possible to take, for example, the pivot module  400  and to place it in the housing  206  without any prior manipulation. 
     The present invention makes it possible to dispense with orientation of the parts relative to each other. Furthermore, this makes it possible to simplify fixing of the spring and thus to simplify the assembly process. In fact, these parts of the shock-absorber bearing  100  are designed so that the elastic means  300  are placed on the support  200  then fixed without there being any need for manipulation for the spring of  FIG. 1 , which is of the axial type and which has the shape of a lyre, to be able to be supported under the returns of the semi-circular rims  11   a ,  11   b  of the support. The shock-absorber bearing  100  can then be mounted vertically or axially. This means that the various parts forming the shock-absorber bearing  100  can be assembled by placing them one on the other from the top. 
     Consequently, the obstacles with respect to complete and effective automation of the assembly process are removed. 
     In order that the elastic means  300  can be fixed on the support  200 , fixing means  500  are used. Advantageously, these fixing means  500  are designed so that the various parts, including the fixing means  500 , remain angularly free relative to each other. In the following description, we will consider the example according to which the support  200 , the housing  206 , the pivot module  400  and the elastic means  300  are circular parts. 
     In a first solution which can be seen in  FIGS. 4 a , 4 b    and  6 , the fixing means  500  comprise a supplementary part  510  which serves to fix the elastic means on the support. This supplementary part has the shape of a cap  510  which is fixed on the support  200 . This cap  510  is designed so that, during fixing to the support  200 , the elastic means  300  situated between said cap  510  and said support  200  are in part squeezed by the cap  510  and the support  200 . Preferably, the squeezing is effected over a specific zone of the elastic means  300 , preferably over the annular parts  303 , so that the elastic properties are not altered. 
     This cap has the shape of a ring  511 . This ring comprises a flat ring which has a lower face  512 , i.e. the face opposite the support  200 , from which a peripheral blade  513  extends. This peripheral blade  513  extends perpendicularly to the plane of the flat ring. The dimensions are defined so that, when the cap  510  is placed on the support  200 , the blade  513  is in contact with the support at the level of the external flank  204 . The dimensions of the cap  510  make it possible for the latter to be slid over the support  200 . A cap  510  which can be dismantled is therefore obtained. 
     In an alternative to this first solution, the support  200  comprises a slot into which the blade of the cap is inserted. This slot is the negative of the blade so that it can be inserted perfectly in said slot. Interaction between the blade  513  and the walls of the slot generates a friction which ensures fixing of the blade  513  in the slot and therefore of the cap  510  on the support  200 . 
     In a second solution which can be seen in  FIG. 8 , the fixing means  500  comprise rivets. These rivets have the shape of strips or fins  530  provided on the support  200  at the level of the top  203   a  of the support  203 . These strips are disposed so that their width extends parallel to the central axis of the support and so that their length extends perpendicularly to the central axis of the support. For preference, the strips are designed to assume the shape of the internal flank of the rim of the support  200 . In fact, if the support  200  is of a circular shape, the internal flank of the rim has a circular shape and the strips have a curve which follows the shape of the internal flank of the rim  200 . The various strips are therefore designed to form a circle. During assembly of the annular spring  301 , i.e. of the elastic means  300 , the annular portions  303  are placed on the top  203   a  of the rim  203 . Fixing of the annular spring takes place by folding down the strips which form the rivets over said annular spring  301 . These thus folded-down strips squeeze the annular portions  303  of the annular spring so that the latter can no longer move. In order to fix said annular spring  301 , it will be understood that the fixing means  500  comprise at least two strips, given that the greater the number of strips, the more effective the fixing and centring. Effectively the greater the number of strips, the more will the surface of the annular spring  301  be squeezed by the strips. Likewise, the greater the number of strips, the more stable will be the annular spring  301  during assembly. 
     In a third solution which can be seen in  FIG. 7 , the fixing means which make it possible to fix the annular spring comprise a material linkage  520 . This material linkage is placed between the support  203  and the annular spring. This material linkage has the form of a weld/solder joint or of a glue used for fixing, integrally, the annular spring  301  to the support  200 . This material linkage can be formed by a multitude of weld/solder spots or by glue or by a continuous line which runs across the entire perimeter of the annular spring  301 . This embodiment has the advantage of using a tested and simple technology so that the assembly process is not made complex. 
     These various solutions make a vertical assembly possible. There is understood by this that the various parts are assembled according to their disposition in the structure of the shock-absorber bearing  100 . Hence, for said bearing  100 , the assembly process consists of providing the support  200 . Then the pivot module  400  is provided which is then placed in the housing of the support  200 . Then, the spring is provided which comes to be placed on the support. Finally, the fixing means  500  are placed and fixed on the support  200 . By combining the advantage of being able to produce a vertical or axial assembly with the fact that the parts are not orientated relative to each other, an assembly process which can be automated easily is obtained. 
     Advantageously, all the parts forming the shock-absorber bearing  100  are produced so that they are angularly free relative to each other. Thus the housing  206 , the pivot module  400 , the elastic means  300  are angularly free relative to each other and, preferably, are circular. This configuration makes it possible to take each part as it comes without orientating it. 
     In a first variant of the first embodiment which can be seen in  FIG. 9 , the support  200  is not circular, it can be of any shape. In this variant, the support has a mounting zone  209  representing the zone reserved for mounting the elastic means  300 . This mounting zone  209  has a shape similar to that of the housing  206 , of the pivot module  400  and of the elastic means  300 , i.e. circular, in the example taken for the first embodiment. The fact that the support  200  has a mounting zone  209  which has a shape similar to that of the housing  206 , of the pivot module  400  and of the elastic means  300  allows simplified mounting in all cases. Effectively, this specific zone  209  allows use of fixing means  500  according to the three solutions explained previously since one specific zone is specially designed. This mounting zone  209  requires a design of the support  200 , the dimensions of which take into account the presence of said mounting zone  209 . For example, if the support  200  has any shape, such as a triangular shape, the space for using the fixing means  300  according to the three solutions explained previously is not necessarily present. It is on this mounting zone  209  that the elastic means  300  will be supported, in part, and will be fixed. Hence, the mounting zone  209  will be the zone on which the elastic means  300  will be fixed by a material linkage such as welding or gluing. This zone can also be used so that a cap  510  can be fixed there, a slot which is the negative of the blade  513  of the cap  510  is hollowed out in order to allow fixing of said cap. Finally, this mounting zone  209  can be the zone on which the strips serving as rivets are provided. 
     In a second variant which can be seen in  FIG. 10 , the support  200  and the base element of the movement  500  in which the shock-absorber bearing  100  is placed are simply one and the same part, the support  200  and the base element are therefore monobloc. It is therefore understood that the base element has a recess provided to form a base pierced by a hole and forming the housing  206  in which the pivot module  400  is placed. It is likewise understood that this second variant can exist together with the first variant. In fact, as a bridge or a bottom plate has any shape, a provided mounting zone  209  makes it possible to be sure of being able to install the fixing means and thus to retain the pivot module  400  in the housing. 
     It will be understood that various modifications and/or improvements and/or combinations which are evident to the person skilled in the art can be applied to the various embodiments of the invention which is presented above without departing from the scope of the invention defined by the annexed claims. 
     In fact, it is possible that the pivot module  400  can be formed from a single stone or that the pierced stone and the counter-pivot stone are integral one with the other. It is understood that the pierced stone and the counter-pivot stone can slide one into the other or be monobloc. These possibilities make it possible to limit the number of parts of the shock-absorber bearing.