Abstract:
The invention concerns a timepiece comprising a middle part ( 30 ) closed by a back cover and a crystal, said middle part ( 30 ) comprising a peripheral shoulder ( 34 ) in which a groove ( 37 ) is arranged, said groove being disposed on a surface of the shoulder parallel to the central axis of the middle part (C), said timepiece comprising a rotating bezel system ( 20 ) rotatably mounted on said peripheral shoulder, characterised in that said rotating bezel system includes a bezel ring ( 40, 41 ) provided with at least a first recess ( 46 ) disposed on a surface of the bezel intended to face said groove when said rotating bezel system ( 20 ) is fitted onto the middle part, said rotating bezel system ( 20 ) further comprising a spring means ( 80 ) extending both into said at least one first recess ( 46 ) of the bezel and at the same time into the groove ( 37 ) in the middle part so as to hold the rotating bezel system ( 20 ) on the middle part ( 30 ) of the timepiece.

Description:
This application claims priority from European Patent Application No. 12171071.9 filed Jun. 6, 2012, the entire disclosure of which is incorporated herein by reference. 
     The present invention concerns a timepiece comprising a middle part closed by a back cover and a crystal, said timepiece further comprising a rotating bezel system secured to said middle part. 
     The technical field of the invention is the technical field of fine mechanics. 
     BACKGROUND OF THE INVENTION 
     The present invention concerns a rotating bezel system for a timepiece. 
     Known rotating bezel systems  2 , seen in  FIG. 1 , comprise a rotating bezel  4  taking the form of an annular part having a top surface and a bottom surface, with the top surface being the part visible to the user. This bezel has a notch  6  on the bottom surface thereof. The rotating bezel system further includes a spring means  8 . This spring means  8  is inserted between the rotating bezel and the middle part  3  of timepiece  1 , when bezel  4  is forcibly fitted onto the middle part of the timepiece. This spring means  8  takes the form of a flat ring comprising leaves on the surface thereof facing the notch in the bezel. These leaves are arranged to tilt relative to the plane of the flat ring. The leaves have some elasticity so that the spring means acts on the rotating bezel to exert a vertical force. This vertical force has a tendency to push the bezel off the middle part of the timepiece. 
     Further, the leaves serve to cooperate with the notch in the bottom surface of the bezel. The leaves and notch are thus configured so that the bezel can only rotate in one direction. The leaves prevent the bezel from rotating if the user attempts to rotate said bezel in the wrong direction. Generally, the bezel and the spring means are made of steel which has the advantage of being durable and inexpensive. 
     The bezel is driven onto the middle part of the watch case. To achieve this, the middle part has a peripheral shoulder in which said rotating bezel system is placed, the vertical wall of said shoulder having a peripheral groove  10 . The bezel is an annular part having a peripheral rim on the bottom surface thereof. The rim is provided with a continuous protruding portion  12  extending along said rim towards the axial centre of the bezel. When said rotating bezel system is driven onto the middle part of the watch case, the continuous protruding portion is inserted into the peripheral groove of the shoulder ensuring that the bezel is held vertically on the middle part. 
     One drawback of this system is that it requires significant force to assemble said rotating bezel system. Indeed, when the bezel is forcibly fitted onto said middle part so that the continuous protruding portion is inserted into the peripheral groove, significant stresses are applied to the bezel. These stresses may, if incorrectly applied, cause deformations of the bezel and thus malfunction of the rotating bezel system. 
     Moreover, the snap fit assembly of the bezel is permanent. Indeed, it is impossible to remove the rotating bezel system from the middle part afterwards. Attempts to remove said rotating bezel system result in the destruction of said system. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to overcome the drawbacks of the prior art by proposing to provide a rotating bezel system for a timepiece which is simpler to assemble onto the watch case, imposing less stress on said system and which can be more easily disassembled. 
     The invention therefore concerns a timepiece comprising a middle part closed by a back cover and a crystal, said middle part comprising a peripheral shoulder in which a groove is arranged, said groove being disposed on a surface of the shoulder parallel to the central axis of the middle part, said timepiece comprising a rotating bezel system rotatably mounted on said peripheral shoulder, characterised in that said rotating bezel system includes a bezel ring provided with at least a first recess disposed on a surface of the bezel intended to face said groove when said rotating bezel system is fitted onto the middle part, said rotating bezel system further comprising a spring means extending both into said at least one first recess of the bezel and at the same time into the groove in the middle part so as to hold the rotating bezel system on the middle part of the timepiece, and a toothed element having a toothing arranged to cooperate with a corresponding toothing arranged on the spring means so as to index the angular position of the bezel. 
     A first advantage of the present invention is that the rotating bezel system according to the invention is simpler to assemble. Indeed the system according to the present invention takes the form of a pre-assembled system. It is thus clear that the various elements forming the rotating bezel system are assembled to each other and that, afterwards, said system only needs be secured to the middle part of the watch case. Thus, it is simpler to store and transport the rotating bezel systems since they are already assembled. 
     A second advantage is that less stress is required for assembly with the present invention. Indeed, since the spring means is the means for retaining the rotating bezel system on the middle part of the watch case, the stress exerted during assembly is partly absorbed. This stress is absorbed by the spring which will deform and facilitate assembly. 
     In a first advantageous embodiment, the spring means includes a spring ring in the form of an open ring with at least one zone having a minimum radius and one zone having a maximum radius so that the zone having a maximum radius cooperates with said at least one first recess and the zone having the minimum radius cooperates with the groove in the peripheral shoulder. 
     In a advantageous embodiment, the bezel comprises a second recess in which the toothed element is arranged. 
     In a advantageous embodiment, said spring ring is a flat ring whose toothing is arranged on the external wall of said at least one zone having a minimum radius, the first and second recesses then merging. 
     In a advantageous embodiment, said spring ring comprises two ends, one of which has a raised part, said raised part comprising a vertically oriented curved portion and a flat portion parallel to said spring ring, said flat portion comprising, on the external wall thereof, the toothing cooperating with the toothed element. 
     In another advantageous embodiment, the bezel is made in at least two parts and includes a bezel ring and a support ring having complementary profiles so that assembling the bezel ring to the support ring forms the first and second merged recesses. 
     In another advantageous embodiment, the bezel is made in at least two parts and includes a bezel ring and a support ring having complementary profiles so that assembling the bezel ring to the support ring forms the second recess, said support ring comprising the first recess. 
     In another advantageous embodiment, said spring ring has three angularly distributed zones having a minimum radius. 
     In another advantageous embodiment, the zones of said spring ring having a minimum radius are angularly distributed. 
     In another advantageous embodiment, said toothing is arranged on each zone having a minimum radius. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects, advantages and features of the bezel system according to the present invention will appear more clearly in the following detailed description of at least one embodiment of the invention, given solely by way of non-limiting example and illustrated by the annexed drawings, in which: 
         FIG. 1  is a schematic view of a bezel system of the prior art. 
         FIG. 2  is a cross-section of a timepiece provided with a bezel system. 
         FIG. 3  is a schematic view of the bezel system according to the invention. 
         FIG. 4  is a schematic view of a first embodiment of the bezel system of the invention. 
         FIGS. 5 to 6  are schematic views of the spring of the first embodiment of the bezel system of the invention. 
         FIG. 7  is a schematic view of a variant of the first embodiment of the bezel system of the invention. 
         FIG. 8  is a schematic view of a second embodiment of the bezel system of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention proceeds from the general inventive idea which consists in providing a rotating bezel system which is simpler to assemble. 
     A timepiece  1 , seen in  FIG. 2 , comprises a middle part  30  closed by a back cover  31  and a crystal  32 . This middle part  30  includes a peripheral shoulder  34  defined by a lateral wall  36  and a base  38 . This shoulder  34  defines a site in which the rotating bezel system  20  is placed. 
     Rotating bezel system  20 , seen in  FIG. 3 , includes a bezel  40 , which is the visible part handled by the user. Rotating bezel system  20  also includes a toothed element  60  arranged on bezel  40  and a spring means  80  cooperating with toothed element  60  to allow rotating bezel system  20  to rotate relative to middle part  30  of timepiece  1 . 
     Advantageously according to the invention, spring means  80  is also used to hold rotating bezel system  20  on middle part  30  of watch case  1 . 
     In a first embodiment shown in  FIG. 4 , spring means  80  takes the form of a spring with several levels, in three dimensions. 
     Rotating bezel system  20  of this embodiment includes a bezel  41 . This bezel  41  takes the form for example of a ring comprising a top surface  41   a  and a bottoms surface  41   b.  From the bottom surface  41   b,  a peripheral rim  42  extends perpendicularly to the plane of bezel  41 . This peripheral rim  42  includes an inner lateral wall  42   a  and an outer lateral wall  42   b.  The inner lateral wall  42   a  has a second recess  44  having a parallelepiped profile such as a square or rectangular profile. This second recess  44  covers the entire length of said rim  42  so as to be circular. Toothed element  60  is arranged in this second recess  44 . This toothed element  60  may take the form of a toothing  61  made directly in said first recess of the rim or, as in the illustrated example, the form of a toothed ring  62  carrying a toothing  63  on the inner surface thereof. This toothed ring  62  is placed in said second recess  44 . Means are provided for angularly securing said toothed ring  62  to bezel  41 , such as for example spot welds or adhesive spots. However, toothing  63  forming toothed element  60  could be made directly on the inner lateral wall  42   a  of peripheral rim  42 , there being no second recess  44  in rim  42 . 
     Spring means  80 , seen in  FIGS. 5 and 6 , takes the forms of a spring ring  82 . This spring ring has a top surface and a bottom surface, said top surface being the surface visible from above when said spring ring is placed on any level. The spring ring comprises an open ring  800 , comprising at least one zone having a smaller radius of curvature than the radius of curvature of said non-closed ring. It is thus clear that said spring ring includes at least one zone  802  having a maximum radius and at least one zone  804  having a minimum radius. In the case shown in  FIG. 5 , the spring ring includes three regularly angularly distributed zones  802  having a minimum radius. Said open ring  800  also has, at one of the ends  806  thereof, a raised part  808 . This means that said end has an axial or vertical curvature so that the end is raised and parallel to the plane of spring ring  800 . The raised part thus includes an axially oriented curved portion  808   a  and a flat portion  808   b  parallel to said spring ring  82 . Preferably, this curvature extends from the top surface of spring ring  82 . This raised part  808  includes a toothing  810  on the external surface thereof. This toothing  810  is complementary to the toothing of toothed element  60 , i.e. toothing  63  of toothed ring  62  or toothing  61 . Indeed, when spring ring  82  is fitted into rotating bezel system  20 , the raised part of spring ring  82  is calculated such that said ring faces toothed ring  62 . 
     To mount spring ring  82  in bezel  41 , the bezel has a recess for a spring  46  having a square or rectangular profile which also covers the entire length of said rim  42 . This first recess  46  is located underneath second recess  44  so that a separating wall  48  separates second recess  44  from first recess  46 . The separating wall  48  is preferably shortened so that the second recess  44  and first recess  46  communicate with each other to form a housing  45  for spring ring  82 . Consequently, when the spring ring is assembled, toothing  810  of the outer surface of raised part  808  comes into contact with the toothing of the inner surface of toothed ring  62 , and spring ring  82  is locked into said bezel  41 . The at least one zone  804  having a minimum radius is/are inserted into first recess  46 . Consequently, when toothed ring  62  and spring ring  82  are assembled in bezel  41 , only the at least one zone  802  of maximum radius juts out. 
     The cooperation between toothing  63  of toothed ring  62  and toothing  810  of raised part  808  of spring ring  82  determines the direction of rotation of rotating bezel system  20 . To achieve this, toothing  810  of the outer surface of raised part  808  and the toothing of the inner surface of toothed ring  62  are configured such that each tooth includes an inclined surface and a surface that is straight or merges with radius of toothed ring  62  or of spring ring  82 . When spring ring  82  is mounted in rotating bezel system  20 , the inclined surface of each tooth of toothing  810  of spring ring  82  is in contact with the inclined surface of each tooth of toothing  63  of toothed ring  62 . The rotation of the system is unidirectional, i.e. rotation can occur clockwise or anti-clockwise, however it is possible for rotation to be two-directional. Indeed, if rotating bezel system  20  is rotated in the right direction, the inclined surfaces of the toothing of spring ring  82  and of the toothing of toothed ring  62  slide onto each other to mesh. Conversely, if rotating bezel system  20  is rotated in the wrong direction, the straight surfaces of toothed ring  62  abut on the straight surfaces of spring ring  82  forming a blockage. 
     The lateral wall  36  of shoulder  34  of middle part  30  includes a groove  37  extending along the lateral wall  36  so as to go around shoulder  34 . This groove  37  is used to secure said rotating bezel system  20 . Indeed, when rotating bezel system  20  is assembled on middle part  30  of the watch, driving in said rotating bezel system  20  causes tension stress to be applied to spring ring  82 . As a result of this stress, spring ring  82  is taut and its diameter increases, the spring ring then tending to completely enter the first recess  46 , thereby facilitating the driving in operation. 
     When spring ring  82  is facing groove  37  located on middle part  30 , the stress exerted on said spring ring  82  decreases. The spring ring relaxes to return to its initial position. As they relax, the zones of the spring ring having a maximum radius  802  are inserted into groove  37  of middle part  30  to ensure vertical retention. 
     There is thus obtained a rotating bezel system  20  wherein the zones of spring ring  82  having a maximum radius  802  are inserted into groove  37  of middle part  30  and wherein the zones having a minimum radius  804  are inserted into first recess  46 . 
     Moreover, spring ring  82  has at least one protruding portion  812  on the inner surface  803  thereof. This protruding portion  812  is arranged to cooperate with a hole  39  located on middle part  30  as seen in  FIG. 5 . This hole  39  is placed such that the protruding portion  812  is inserted therein when the rotating bezel system  20  is mounted on middle part  30 . This cooperation locks spring ring  82  angularly relative to middle part  30 . 
     There is thus obtained a spring ring  82  angularly integral with middle part  30  and a bezel  41  which comprises toothed element  60  which can rotate about middle part  30  in at least one predetermined direction. Indeed, when the user decides to rotate rotating bezel system  20 , he has two possibilities: either he rotates rotating bezel system  20  in the direction in which it is intended to rotate, or in the opposite direction. Depending on the direction in which the user rotates the bezel, the teeth of spring ring  82  and the teeth of toothed ring  62  slide over each other to mesh or abut on each other to block rotation. 
     One advantage of rotating bezel system  20  of the invention is that it is easier to assemble on middle part  30  since the stress to be exerted is lower. Indeed, in known systems, vertical retention is achieved by driving in a rigid element which requires exerting significant force to drive in rotating bezel system  20 . This also means that the operation of detaching rotating bezel system  20  from middle part  30  is very complicated, since there is a significant risk of said system breaking. With rotating bezel system  20  of the invention using an elastic element to ensure vertical retention, it is spring ring  82  which is used for vertical retention and which is deformed during the driving in operation. The stress that has to be applied to assemble rotating bezel system  20  of the invention to middle part  30  is thus lower. Consequently, the operation of detaching rotating bezel system  20  from middle part  30  is less complicated. Another consequence is a reduced risk of breaking said rotating bezel system  20 . 
     In a variant of this second embodiment seen in  FIG. 7 , bezel  41  is formed of several parts. Bezel  41  includes a bezel ring  410  and a support element  412  assembled to each other. Bezel ring  410  consists of a ring comprising a top surface  410   a  and a bottom surface  410   b.  Support element  412  takes the form of a support ring  413  having a top surface and a bottom surface. The top surface includes a peripheral top rim  414  having a stair-shaped profile. It is thus clear that said rim has several levels or support surfaces. As a minimum, the peripheral top rim  414  will include at least an intermediate level, support element  412  therefore including three support surfaces at three different heights. The bottom surface includes a peripheral bottom rim  416  extending perpendicularly relative to the plane of support element  412 . The latter has a first recess  418  covering the inner surface of second rim  416  so as to form a circular recess. Bezel ring  410  also has a stair-shaped but complementary profile. This complementary stair-shaped profile is arranged to cooperate with the stair-shaped profile of support element  412 . Thus, when the bezel is assembled, toothed ring  62  is placed on one of the support surfaces of support ring  412 , preferably, the lowest surface. Then, bezel ring  410  is assembled to support ring  413  by a driving in, screwing or any other securing method. The stair-shaped profiles of bezel ring  410  and of support ring  413  work together. Preferably, the stair-shaped profiles are arranged so as to form the second recess  44  in which toothed ring  62  is placed. Toothed ring  62  is held between bezel ring  410  and support ring  413 . Spring ring  82  is secured to bezel  41  so that the zones having a maximum radius  802  are inserted into the first recess  418  of the bottom rim  416 . Consequently, in this case, the raised part  808  of spring ring  82  and more particularly toothing  810  of said raised part, cooperates with the toothing of toothed ring  62 . 
     In a second embodiment visible in  FIG. 8 , spring ring  82  has no raised part. Said spring ring  82  is an open or non-closed ring  820  comprising at least one zone having a maximum radius  822  and at least one zone having a minimum radius  821 . In the case shown in  FIG. 8 , the spring ring includes three, regularly angularly spaced zones having a maximum radius  822 . This second embodiment is different in that the toothing  823  cooperating with the toothing of toothed element  62  is placed on said at least one zone having a maximum radius  822 . This arrangement simplifies the bezel since only one recess has to be arranged on the inner wall of the bezel or of the support element, as seen in  FIG. 3 . 
     It will be clear that various alterations and/or improvements and/or combinations evident to those skilled in the art may be made to the various embodiments of the invention set out above without departing from the scope of the invention defined by the annexed claims.