Patent Publication Number: US-9897973-B2

Title: Pivoting assembly for a timepiece

Description:
This application claims priority from European Patent Application No. 15158296.2 filed Mar. 9, 2015, the entire disclosure of which is hereby incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a pivoting assembly for a timepiece and, more particularly, to a gear train or to a resonator for a timepiece. 
     BACKGROUND OF THE INVENTION 
     US Patent Applications 2015/098310 and 2015/098311 disclose a balance spring resiliently locked on an arbor by a washer. This type of configuration avoids having to fit the balance spring collet onto an arbor and then bonding it at its points of contact. 
     However, the use of such a washer results in a total height which makes it impossible to implement in movements of small thickness. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to overcome all or part of the aforecited drawbacks by proposing a pivoting assembly using a resilient washer disclosed in one of US Patent Applications 2015/098310 and 2015/098311 which includes a total thickness allowing the application thereof to any type of timepiece movement. 
     To this end, the invention relates to a pivoting assembly comprising an arbor rotatably mounted between two bearings, a member mounted on the arbor with the aid of at least one resilient washer, characterized in that at least one of the two bearings comprises a limit stop which is arranged to enter into direct contact with said at least one resilient washer in order to restrict the relative movement between the arbor and the two bearings. 
     It is thus understood that all or part of the extra height due to the use of said at least one resilient washer is compensated by replacing the shoulder formed on the arbor by the upper surface of said at least one washer. Thus, the limit stop of at least one of the bearings acts directly against the resilient washer and no longer against the arbor in order to restrict the relative movement between the arbor and its bearings. 
     In accordance with other advantageous variants of the invention:
         said member is mounted between a shoulder of the arbor and said at least one resilient washer;   said member is mounted on the arbor between two resilient washers;   said member is a balance spring and, preferably a balance and a roller are also mounted on the arbor;   said member is a wheel and, preferably, a pinion is also mounted on the arbor;   said member is a pallet lever, a detent, a mainspring or a balance;   the two bearings each include at least one jewel arranged to receive a pivot formed on each end of the arbor;   each at least one jewel is resiliently mounted in its associated bearing in order to dampen shocks received by the arbor;   the two bearings are respectively mounted in a plate and a bridge.       

     Moreover, the invention relates to a timepiece comprising at least one pivoting assembly according to any of the preceding variants. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages will appear clearly from the following description, given by way of non-limiting illustration, with reference to the annexed drawings, in which: 
         FIG. 1  is a view of a regulating member using a resilient washer; 
         FIG. 2  is a view of a first embodiment of the invention; 
         FIGS. 3 and 4  are views of a second embodiment of the invention. 
         FIG. 5  is a view of a third embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     US Patent Applications 2015/098310 and 2015/098311, incorporated by reference in the present description, disclose a balance spring resiliently locked between the shoulder of an arbor and a resilient washer. One such configuration is shown in  FIG. 1 . There is shown a regulating member  1  formed of an arbor  2  mounted between a bridge  3  and a plate  4 . Regulating member  1  includes a balance spring  5  and a balance  6  which are mounted between a shoulder of arbor  2  and a resilient washer  7 . 
     Arbor  2  further includes two shoulders  8 ,  8 ′ each intended to enter into contact with a bearing  9 ,  9 ′ respectively mounted in bridge  3  and plate  4 . It is evident that the configurations described in US Patent Applications 2015/098310 and 2015/098311 require a significant distance between resilient washer  7  and bearing  9  which may make them impossible to implement in a movement of small thickness. 
     To compensate for this extra thickness of the resilient washer, the invention relates to a pivoting assembly comprising an arbor rotatably mounted between two bearings and a member mounted on the arbor with the aid of at least one resilient washer. Advantageously according to the invention, at least one of the two bearings includes a limit stop which is arranged to enter into direct contact with said at least one resilient washer in order to restrict the relative movement between the arbor and its bearings. 
     It is thus understood that all or part of the extra height due to the use of a resilient washer is compensated by replacing the specially formed shoulder on the arbor by the upper surface of said at least one washer. Thus, the limit stop of at least one of the bearings acts directly against the resilient washer and no longer against the arbor in order to restrict the relative movement between the arbor and its bearings. 
     It is also understood that an arbor may also comprise at least two resilient washers, either attaching a single member, or each resilient washer attaching a distinct member against a distinct shoulder of the arbor. Advantageously, this means that each of the two bearings can enter into direct contact with one of the resilient washers used on the arbor in order to restrict the relative movement between the arbor and its bearings while minimising the height of the pivoting assembly. 
     For better comprehension of the invention,  FIG. 2  relates to a first embodiment forming a gear train type pivoting assembly. Pivoting assembly  11  comprises an arbor  12  rotatably mounted between two bearing assemblies  13  and  14  respectively mounted in a plate  15  and a bridge  16 . In the example illustrated in  FIG. 2 , each bearing assemblies  13 ,  14  comprises a jewel or jewel hole  17 ,  18  arranged to receive a pivot  19 ,  20  formed on each end of arbor  12 . 
     As seen in  FIG. 2 , a member forming a wheel  21  is mounted between a shoulder of arbor  12  and a resilient washer  22 . It can also be seen that arbor  12  comprises a pinion  23  underneath wheel  21 . Advantageously according to the invention, at least one of the two bearing assemblies  13 ,  14  comprises a limit stop  25 , which is arranged to enter into direct contact with resilient washer  22  in order to restrict the relative movement between arbor  12  and its bearing assemblies  13 ,  14 . 
     The second embodiment shown in  FIGS. 3 and 4  better illustrates the limit stops according to the invention. Thus,  FIGS. 3 and 4  relate to a second embodiment forming a resonator type pivoting assembly. Pivoting assembly  31  comprises an arbor  32  rotatably mounted between two bearing assemblies  33  and  34  respectively mounted in a plate  35  and a bridge  36 . In the example illustrated in  FIG. 3 , each bearing assembly  33 ,  34  comprises at least one jewel or jewel hole  37 ,  38  and, preferably, a jewel  37 ,  38 —endstone  37 ′,  38 ′ assembly arranged to receive a pivot  39 ,  40  formed on each end of arbor  32 . 
     As seen in  FIGS. 3 and 4 , a member forming a balance spring  41  is mounted between a shoulder  44  of arbor  32  and a resilient washer  42 . It can also be seen that arbor  32  comprises a balance  43  and a roller  46  provided with an impulse pin  47 . Advantageously according to the invention, at least one of the two bearing assemblies  33 ,  34  comprises a limit stop  45 , which is arranged to enter into direct contact with resilient washer  42  in order to restrict the relative movement between arbor  32  and its bearing assemblies  33 ,  34 . 
     As seen in  FIG. 3 , it can also be seen that each at least one jewel  37 ,  38  and preferably, a jewel  37 ,  38 —endstone  37 ′,  38 ′ assembly, is resiliently mounted in its associated bearing assembly  33 ,  34  in order to dampen shocks received by arbor  32 . In the example of  FIG. 3 , resilience is provided by a lyre-shaped spring  48 ,  49  respectively mounted between plate  35  and endstone  37 ′, and bridge  36  and endstone  38 ′. 
       FIG. 5  relates to a third embodiment forming an alternative resonator type pivoting assembly to the second embodiment. Pivoting assembly  51  comprises an arbor  52  rotatably mounted between two bearing assemblies  53  and  54  respectively mounted in a plate  55  and a bridge  56 . In the example illustrated in  FIG. 5 , each bearing assembly  53 ,  54  comprises at least one jewel or jewel hole  57 ,  58  and, preferably, a jewel  57 ,  58 —endstone  57 ′,  58 ′ assembly arranged to receive a pivot  59 ,  60  formed on each end of arbor  52 . 
     As seen in  FIG. 5 , a member forming a balance spring  61  is mounted between a shoulder of arbor  52  via a balance  63  and a resilient washer  62 . It can also be seen that arbor  52  comprises a roller  66  provided with an impulse pin. Advantageously according to the invention, at least one of the two bearing assemblies  53 ,  54  comprises a limit stop  65 , which is arranged to enter into direct contact with resilient washer  62  in order to restrict the relative movement between arbor  52  and its bearing assemblies  53 ,  54 . 
     As shown in  FIG. 5 , it can also be seen that each at least one jewel  57 ,  58  and preferably, a jewel  57 ,  58 —endstone  57 ′,  58 ′ assembly, is resiliently mounted in its associated bearing assembly  53 ,  54  in order to dampen shocks received by arbor  52 . In the example of  FIG. 5 , resilience is provided by a lyre-shaped spring  68 ,  69  respectively mounted between plate  55  and endstone  57 ′, and bridge  56  and endstone  58 ′. 
     Regardless of the embodiment, it is thus understood that all or part of the extra height due to the use of resilient washer  22 ,  42 ,  62  is compensated by replacing the shoulder  8  formed on arbor  2  (illustrated in  FIG. 1 ) by the upper surface of resilient washer  22 ,  42 ,  62 . Thus, limit stop  25 ,  45 ,  65  of at least one of bearing assemblies  13 ,  14 ,  33 ,  34 ,  53 ,  54  acts directly against resilient washer  22 ,  42 ,  62  and no longer against arbor  12 ,  32 ,  52  in order to restrict the relative movement between arbor  12 ,  32 ,  52  and its bearing assemblies  13 ,  14 ,  33 ,  34 ,  53 ,  54 . 
     Of course, this invention is not limited to the illustrated example but is capable of various variants and modifications which will appear to those skilled in the art. In particular, other members may be mounted instead of or in addition to the members cited below. By way of non-limiting example, said member or an additional member could thus be an escapement lever, a detent escapement, a mainspring of a barrel or striking mechanism, or even a balance. 
     It is also possible to envisage an arbor comprising two resilient washers, each attaching a distinct member to one end of the arbor, each limit stop of one of the two arbor bearings being arranged to enter into direct contact with one of the two resilient washers in order to restrict the relative movement between the arbor and its bearings. 
     Finally, in a non-limiting manner, in a last embodiment, the pivoting assembly could also comprise a member formed, for example, of at least one lever of a pallets mounted on an arbor (also called a staff) between two resilient washers. The limit stop of each of the two bearings respectively mounted in a plate and in a bridge are preferably arranged to enter into contact with one of the resilient washers in order to restrict the relative movement between the arbor and its bearings. The member may also comprise pallet-stones, a fork and a guard pin, each of which may be integral with the pallet lever or simply fixed to the pallet lever.