Abstract:
The present invention concerns an assembly for holding or supporting a timepiece balance spring including a balance spring stud and a stud-holder, wherein said stud-holder includes:
       a base comprising an upper face and a lower face extending along a longitudinal axis;   characterized in that the base includes a lug of non-constant shape protruding from one of the faces, said assembly further comprising a holding plate including a first opening and a second opening separated by a deformable arm, with the stud engaging in the second opening.

Description:
This application claims priority from European Patent Application No 14199751.0 filed on Dec. 22, 2014; the entire disclosure of which is incorporated herein by reference. 
     The present invention concerns an assembly for holding or supporting a timepiece balance spring including a balance spring stud and a stud-holder, wherein said stud-holder includes:
         a base comprising a first stop member extending along a longitudinal axis of said base;   means of securing said stud-holder to an escapement mechanism.       

     PRIOR ART 
     In a mechanical watch, it is usual to use a regulating member comprising a sprung-balance device. Conventionally, the inner end of the balance spring is attached to a collet provided on the balance staff. In order to attach and position the inner end of the balance spring, it is known to use a stud-holder housing a balance spring stud, in association with a clamping screw to clamp the stud against the portion of the balance spring engaged in the stud-holder. 
     In such an assembly, the stud-holder is conventionally attached to a balance-cock also used for attaching one of the ends of the balance staff. In practice, during assembly and/or timing, the operations to be performed with these various elements are difficult, since access is restricted and the parts are of very small dimensions. Moreover, with such configurations, it is common for the balance spring clamping screw or the balance spring stud-holder to come loose, and/or be lost during an operation such as adjustment of the active length of the balance spring. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to overcome the drawbacks of the prior art by proposing to provide an assembly for holding or supporting a timepiece balance spring which allows simplified assembly or disassembly of the balance spring stud. 
     To this end, the invention concerns an assembly for holding or supporting a timepiece balance spring including a balance spring stud and a stud-holder, wherein the stud-holder includes: 
     a base comprising an upper face and a lower face extending along a longitudinal axis; 
     characterized in that the base comprises a lug forming a protuberance from one of said faces, said assembly further comprising a holding plate including a first opening and a second opening separated by a deformable arm, the stud engaging in the second opening, said first opening being arranged to cooperate with the lug, the cross-section of the lug having a shape such that a rotation of said holding plate causes a deformation of the deformable arm constricting the second opening and clamping the stud. 
     The invention also concerns an assembly for holding or supporting a timepiece balance spring including a balance spring stud and a stud-holder, wherein said stud-holder includes: 
     a base comprising an upper face and a lower face extending along a longitudinal axis and a first opening; 
     characterized in that the base includes a second opening separated from said first opening by a deformable arm, the stud engaging in the second opening, said assembly further including a lug arranged to cooperate with said first opening, the cross-section of the lug has a shape such that a rotation of the lug causes a deformation of the deformable arm constricting the second opening and clamping the stud. 
     The invention also concerns an assembly for holding or supporting a timepiece balance spring including a balance spring stud and a stud-holder, wherein said stud-holder includes: 
     a base comprising an upper face and a lower face extending along a longitudinal axis and a hole; 
     characterized in that the base includes a holding plate provided with a first opening and a second opening separated by a deformable arm, the stud engaging in the second opening, said assembly further including a lug arranged to cooperate with said first opening and the hole allowing the holding plate to be fixed on the base, the shape of the cross-section of said lug having such that a rotation of the lug causes a deformation of the deformable arm constricting the second opening and clamping the stud. 
     In a first advantageous embodiment, the first opening is circular, said lug taking the form of a cylindrical part wherein at least one area of the outer wall has a protuberance for application of stress on the deformable arm to reduce the size of the second opening. 
     In a second advantageous embodiment, the first opening and said lug have an elliptical shape, the main axis of said lug being offset angularly with respect to the longitudinal axis of the base for application of stress on the deformable arm to reduce the size of the second opening. 
     In a third advantageous embodiment, the first opening and said lug have an elliptical shape, the main axis of said first opening being offset angularly with respect to the longitudinal axis of the base for application of stress on the deformable arm to reduce the size of the second opening. 
     In a fourth advantageous embodiment, the base includes a recess in which a shock absorber system is placed. 
     In a fifth advantageous embodiment, the recess is placed such that the central axis of the recess coincides with the axis of the lug. 
     In a sixth advantageous embodiment, the lug includes a recess in which a shock absorber system is placed. 
     In another advantageous embodiment, the hole in the base is blind, said base comprising a recess positioned such that the central axis of the recess coincides with the axis of the lug, in which a shock absorber system is placed. 
     In another advantageous embodiment, said assembly further includes a male interface arranged on the holding plate and a female interface arranged on said lug in order to secure the holding plate to said lug. 
     In another advantageous embodiment, said assembly further includes a male interface arranged on the base and a female interface arranged on said lug in order to secure the lug to said base. 
     In another advantageous embodiment, the assembly further includes a male interface arranged on the holding place and a female interface arranged on said lug in order to secure the lug to said base. 
     In another advantageous embodiment, the male interface and the female interface are screw threads. 
     In another advantageous embodiment, the female interface comprises in the thickness thereof at least one cavity formed by a passage which is parallel to the central axis of the lug and open on the lower surface of the lug, and, secant with said first passage and opposite the upper surface, a blind slot used for locking the holding plate in a bayonet fitting. 
     In another advantageous embodiment, the female interface comprises in the thickness thereof at least one cavity formed by a passage which is parallel to said central axis of the lug and open on the upper surface of the lug, and, secant with said first passage and opposite the lower surface, a blind slot used for locking the holding plate in a bayonet fitting. 
     In another advantageous embodiment, the holding assembly further includes adjustment means comprising a toothed wheel arranged on the balance cock cooperating with a toothing arranged on the holding plate, said wheel being provided with a slot so that a tool can rotate said toothed wheel, causing the holding plate to rotate. 
     In another advantageous embodiment, the holding assembly further includes adjustment means comprising a first notch arranged on the balance cock and a second notch arranged on the holding plate, the first notch and the second notch being arranged such that a tool inserted in the first and second notch can rotate the holding plate with respect to the balance cock. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects, advantages and features of the 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: 
         FIGS. 1 and 2  show a diagram of a first embodiment of the holding assembly according to the invention. 
         FIGS. 3 a  to 3 c    show a diagram of a first solution of the first embodiment of the holding assembly according to the invention. 
         FIGS. 4 and 5  show a diagram of a second solution of the first embodiment of the holding assembly according to the invention. 
         FIG. 6  shows a diagram of a second embodiment of the holding assembly according to the invention. 
         FIGS. 7 a  and 7 b    show a diagram of a first solution of the second embodiment of the holding assembly according to the invention. 
         FIGS. 8 a  to 8 c    show a diagram of a second solution of the second embodiment of the holding assembly according to the invention. 
         FIG. 9  shows a diagram of a variant of the second solution of the second embodiment of the holding assembly according to the invention. 
         FIGS. 10 and 11  show a diagram of a first variant of the first and second embodiments of the holding assembly according to the invention. 
         FIG. 12  shows a diagram of a second variant of the first and second embodiments of the holding assembly according to the invention. 
         FIG. 13  shows a diagram of an alternative of the first and second embodiments of the holding assembly according to the invention. 
         FIGS. 14, 17 and 18  show a diagram of a third variant of embodiments of the holding assembly according to the invention. 
         FIGS. 15 a , 15 b , 16 a  and 16 b , 19 a  and 19 b    show a diagram of another variant of embodiments of the holding assembly according to the invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention proceeds from the general idea of providing an assembly for holding or supporting a timepiece balance spring permitting simpler assembly/disassembly of the balance spring stud. 
     In a first embodiment seen in  FIG. 1  there is shown a schematic view of an assembly  1  for holding or supporting a timepiece balance spring according to a first embodiment. This holding assembly  1  includes a stud-holder  3  arranged to be attached to the balance-cock  5 , also referred to as the base; the latter has a longitudinal axis D. The holding assembly also includes a balance spring stud  9  attached to one coil of the balance spring. Stud-holder  3  is used to secure the stud to the cock. 
     In this first embodiment seen in  FIGS. 1 and 2 , stud-holder  3  is composed of a holding plate  32 . Balance cock  5  includes a lug  31  forming a protuberance. This holding plate  32  is a plate pierced with an orifice  34 . Holding plate  32  further includes a deformable bar  35  separating orifice  34  into a first opening  34   a  and a second opening  34   b.    
     First opening  34   b  is the largest portion and is arranged to cooperate with lug  31 . This means that lug  31  is inserted into first opening  34   a.  Second opening  34   b  is used for stud  9 . In fact, stud  9  is inserted in second opening  34   b.    
     Advantageously according to the invention, the shape of lug  31  and that of first opening  34   a  are such that they can act on deformable bar  35  when the holding plate rotates with respect to said lug. This deformation of said bar makes it possible to constrict second opening  34   b  and thereby clamp the stud. 
     In a first solution seen in  FIGS. 3 a , 3 b  and 3 c   , the first portion  34   a  is devised to have a perfectly circular shape, with second portion  34   b  taking the form of a curved groove. In this first solution, lug  31  takes the form of a part with a non-constant cross-section. More specifically, lug  31  will be made to take the form of a substantially circular part having a central axis C wherein one area exhibits a greater distance between the centre of the circle and the end of lug  31 , which provides a separate area as seen in  FIG. 3 a      
     This separate area will be used for clamping stud  9 . Indeed, by pivoting holding plate  32  with respect to lug  31  the separate area of lug  31  will enter into contact with deformable bar  35 . Given that first opening  34   a  is circular, the separate area of lug  31  exerts a stress on deformable bar  35 . This stress thus deforms bar  35  which constricts second opening  34   b.  This constriction causes stress to be exerted on stud  9  so as to clamp said stud. 
     Assembly is achieved by mounting plate  32  on cock  5  and inserting lug  31  in first opening  34   a  of holding plate  32 . Holding plate  32  may or may not be mounted in its permanent angular position. Lug  31  could be provided with a peripheral groove to prevent uncoupling of holding plate  32 . In the case where holding plate  32  is mounted in its permanent angular position, holding plate  32  will be pivoted at a certain angle clockwise or anticlockwise so that the separate area is no longer in contact with deformable bar  35 . The stress applied by this separate area is thus removed and second opening  34   b  returns to its original size as seen in  FIG. 3   b.    
     Stud  9  is then placed in second opening  34   b  and holding plate  32  is rotated with respect to lug  31  to constrict second opening  34   b  and clamp stud  9  on holding plate  32 , as seen in  FIG. 3   c.    
     Lug  31  could be devised as a circular part provided with a projecting portion or a part of ovoid shape. 
     In a second solution seen in  FIGS. 4 and 5 , first opening  34   a  is devised to have an elliptical shape, with second opening  34   b  taking the form of a curved groove. This elliptical shape makes it possible to obtain an elliptical lug  31 . This ellipse has a main axis, called the focal axis, passing through the foci and a secondary axis perpendicular to the focal axis and passing through the centre of the segment formed by the two focal points of said ellipse. In this second solution, lug  31  takes the form of a part of identical cross-section to that of first opening  34   a,  as seen in  FIG. 4 . 
     However, lug  31  is arranged such that its main axis extends parallel to the longitudinal axis of cock  5 , as seen in  FIG. 4 . Consequently, during assembly of holding plate  32 , lug  31  is inserted in first opening  34   a.  As a result, holding plate  32  is in an angularly offset position with respect to alignment with the longitudinal axis of cock  5 . This is due to the fact that, when plate  32  and cock  5  are perfectly aligned, lug  31  and first opening  34   a  of plate  32 , which have an identical shape, do not coincide and are offset angularly. 
     When holding plate  32  is rotated in order to clamp stud  9  inserted in second opening  34   b,  one of the two poles, i.e. one of the two areas the farthest from the centre of lug  31 , enters into contact with deformable bar  35 . Deformable bar  35  is then subjected to stress from lug  31 , causing the deformation of said bar  35 . This deformation of said bar  35  causes a constriction of second opening  34   b  and thus the appearance of stress on stud  9  which clamps the stud as seen in  FIG. 5 . 
     In a second embodiment seen in  FIG. 6 , stud-holder  3  is composed of a holding plate  302  and a lug  301 . The holding plate and the cock form a single part here in which an orifice  304  is made. Lug  301  is a free part here cooperating with said holding plate. 
     Holding plate  302  further includes a deformable bar  305  separating orifice  304  into a first opening  304   a  and a second opening  304   b.  First opening  304   b  is the largest portion and is arranged to cooperate with lug  301 . This means that lug  301  is inserted into first opening  304   a.  Second opening  304   b  is used for stud  9 . In fact, stud  9  is inserted in second opening  304   b.    
     Advantageously according to the invention, the shape of lug  302  and that of first opening  304   a  are such that they can act on deformable bar  305  when lug  302  rotates with respect to the holding plate. This deformation of said bar makes it possible to constrict second opening  34   b  and thereby clamp stud  9 . 
     In a first solution seen in  FIGS. 7 a  and 7 b   , the first opening  304   a  is devised to have a perfectly circular shape, with second portion  304   b  taking the form of a curved groove. In this first solution, lug  301  takes the form of a part with a non-constant cross-section. More specifically, lug  301  will be made to take the form of a substantially circular part having one area that exhibits a greater distance between the centre of the circle and the end of lug  301 , which provides a separate area. 
     This separate area will be used for clamping stud  9 . Indeed, by pivoting lug  301  with respect to holding plate  302 , the separate area of lug  301  will enter into contact with deformable bar  305 . Given that first opening  304   a  is circular, the separate area of lug  301  exerts stress on deformable bar  305 . This stress thus deforms bar  305  which constricts second opening  340   b.  This constriction causes stress to be exerted on stud  9  so as to clamp said stud. 
     Assembly is achieved by mounting lug  301  on cock  5  and inserting it in first opening  304   a  of holding plate  302 . Lug  301  may or may not be mounted in its permanent angular position. In the case where lug  301  is mounted in its permanent angular position, lug  301  will be pivoted at a certain angle clockwise or anticlockwise so that the separate area is no longer in contact with deformable bar  305 . The stress applied by this separate area is thus removed and second opening  304   b  returns to its original size allowing assembly of stud  9 . 
     Stud  9  is then placed in second opening  304   b  and lug  301  is rotated with respect to holding plate  302  to constrict second opening  304   b  and clamp stud  9  on holding plate  302 . 
     Lug  301  could be devised as a circular part provided with a projecting portion or a part of ovoid shape. 
     It is possible to adjust the angular position of stud  9  by sliding it in second opening  304   b.    
     In a first solution seen in  FIGS. 8 a , 8 b  and 8 c   , the first opening  304   a  is devised to have a perfectly ovoid shape, with second portion  304   b  taking the form of a curved groove. This ovoid shape makes it possible to obtain a lug  301  whose external dimensions are different in the x-y plane. The length of lug  301  is greater than its width. In this second solution, lug  301  takes the form of a part of identical cross-section to that of the first opening. 
     However, first opening  304   a  is arranged such that its length extends perpendicularly to the longitudinal axis of cock  5 . Consequently, during assembly of holding plate  302 , lug  301  is inserted in the first opening. As a result, the longitudinal axis of lug  301  is in an angularly offset position with respect to alignment with the longitudinal axis of cock  5 . 
     When holding plate  301  is rotated in order to clamp the stud inserted in the second opening, one of the two poles, i.e. one of the two areas farthest from the centre of lug  301 , enters into contact with deformable bar  305 . Deformable bar  305  is then subjected to stress from lug  301 , causing deformation of the bar. This deformation causes a constriction of second opening  34   b  and thus the appearance of stress on stud  9  in order to clamp the stud. 
     In a variant seen in  FIG. 9 , holding plate  302  is a plate that is fixed on cock  5 . Cock  5  also includes a through or blind hole  500  identical to first opening  304   a  of holding plate  302 . When holding plate  302  is fixed to cock  5 , the two openings  304   a,    500  coincide. This variant advantageously allows the angular position of the holding plate to be modified with respect to that of the cock and thereby allows better positioning of the stud. 
     A male interface  700  and a female interface  702  are provided for the rotatable mounting of lug  301  with respect to holding plate  302 , or of holding plate  32  with respect to lug  31 . Male interface  700  and female interface  702  cooperate with each other to mount the movable part to cock  5  through a movement of rotation. 
     According to a first alternative embodiment, the rotatable mounting is a bayonet fitting. In the case of  FIG. 13 , the lug extends from cock  5  and holding plate  32  is mounted to lug  31 . Female interface  702  is arranged on lug  31 . This female interface  702  consists of at least one cavity  702   a  comprised in the thickness of lug  31 . This cavity  702   a  is formed by a passage  702   b,  which is parallel to said central axis of lug  31  and open on the lower surface of lug  31 , and, secant with said first recess and opposite upper surface  31   a,  a blind slot  702   c.  Slot  702   c  is used for the bayonet locking of holding plate  32 . 
     Male interface  700 , located at first opening  34   a,  consists of at least one protruding portion  701 . This protruding portion  701  is located on the edge of first opening  34   a.  Protruding portion  701  is arranged to cooperate with female interface  702  of the lug. 
     Holding plate  32  is mounted on lug  31  such that protruding portions  701  of holding plate  32  can be inserted in the passage  702   b  of said lug  31 . The lug can then be inserted in the first opening. When the lug reaches an abutment position, the curved arms must be facing the slots. Consequently, a movement of rotation is effected to insert the protruding portions into said slots and to fix said lug to the cock. 
     According to a second alternative, the rotatable mounting is a screw mounting. To achieve this, the female interface and the male interface both consist of a screw thread. 
     In a first variant of the two embodiments seen in  FIGS. 10 and 11 , lug  31 ,  301  includes, on the lower face  31   a,    301   a  thereof, a recess  400 . The recess is for insertion of a shock absorber system  402 . The latter may take a conventional form, i.e. a setting in which a jewel hole and an endstone are arranged, or the form of a single jewel  404 . This single stone  404  is provided with a recess for cooperating with the balance staff and may be force-fitted in recess  400  by means of an elastic ring  406 . The shock absorber system could also take the form of a disc provided with elastic arms. This variant allows for centring between the stud and the balance staff pivot which will cooperate with said shock absorber system. This variant can be developed further by envisaging that lug  301  is itself a shock absorber system. This shock absorber system takes the form of a setting in which a jewel hole and an endstone are arranged. 
     In a second variant, seen in  FIG. 12 , in which lug  301  is a free part provided with a shock absorber system  402 , lug  301  is mounted with height adjustment. To achieve this, a thread  600  is arranged in first opening  304   a  in which lug  301  is inserted. Lug  301  then includes a thread  602  on its outer wall  301   b  to cooperate with thread  600  of holding plate  302 . The height position of the shock absorber system can thus be adjusted by making more or fewer turns with the lug. It will therefore be understood that a preliminary step to mounting the stud is an adjustment in which the lug is inserted in the first opening of the holding plate and then rotated to adjust the height of the shock absorber system. The next step is then the step of setting in place and clamping the stud. 
     In a third variant of the first and second embodiments, adjustment means  800  are provided for the angular adjustment of the holding plate to modify the angular position of said holding plate with respect to the cock while continuing to clamp the stud securely. 
     In the case of the second embodiment in which lug  301  is a part that is added to the base and holding plate  302  is fixed to cock  5 , adjustment means  800  thus includes engagement means  801  arranged on the face of the holding plate opposite the cock and a plurality of receptacles  802  arranged on the face of the cock opposite the holding plate as seen in  FIG. 14 . For example, engagement means  801  include at least one tube  803  protruding from the face of the holding plate opposite the cock, while the plurality of receptacles include a plurality of holes into which the tubes can be inserted. The fact of having a plurality of tubes  803  ensures hold is maintained even if one of tubes  803  breaks. 
     Preferably, the plurality of tubes and the plurality of holes are disposed in a circle. This arrangement has the advantage of allowing the angular position of the holding plate to be modified with respect to the cock and of locking this angular position. Once the angular position has been defined and locked, it is possible to perform the steps of setting the stud in place and clamping the stud to the holding plate. 
     Consequently, since the lug is an added part, said lug simply needs to be inserted in the first holding plate opening and in the cock opening and then rotated to act on the deformable bar of the holding plate in order to clamp the stud. 
     In the case of the first embodiment seen in  FIG. 17 , angular adjustment means are provided. These adjustment means  800  include a toothed wheel  810  arranged on balance cock  5 . This toothed wheel  810  is mounted on an arbor. Toothed wheel  810  is arranged to cooperate with a toothing  812  arranged on the holding plate. More specifically, toothing  812  is arranged on the external wall  32   a  of holding plate  32 . 
     Wheel  810  includes a slot  814  so that a tool, such as a flat-head screwdriver can be used to act on toothed wheel  810 . 
     Thus, in order to modify the angular position of stud  9 , a person engages the flat head of the screwdriver in slot  814  of the toothed wheel and rotates toothed wheel  810 . Toothed wheel  810  meshes with toothing  812  of the holding plate, causing the latter to rotate. 
     It is possible to envisage that adjustment means  800  include a second notch  822  arranged on the holding plate and a first notch  820  arranged on balance cock  5 , as seen in  FIG. 18 . These notches are located opposite each other so that it is possible to place the flat head of a screwdriver in both notches. This arrangement makes it possible to pivot the holding plate by pivoting screwdriver  824  on itself. Simple and inexpensive means for angular adjustment of the holding plate are thus obtained. 
     Further, in another variant, it will be understood that lug  31  and holding plate  32  or holding plate  302  and lug  301  are arranged on the lower face of cock  5 , i.e. on the face located opposite the sprung balance. 
     In another variant seen in  FIGS. 15 a , 15 b , 16 a , 16 b   , the orifice  34 ,  304  of holding plate  32  seen in  FIGS. 15 a , 15 b   , or of balance cock  5  seen in  FIG. 16 a , 16 b   , is separated into a first opening and a second opening by a deformable arm  35   a,    305   a  having one end connected to the wall of orifice  34 ,  304  and one free end. The wall of orifice  34 ,  304  also includes an extension  35   b,    305   b  which may have any shape. This extension makes it possible, during assembly of the stud, for the elastic arm to press the stud against the wall of the second opening  34   b ′,  304   b ′ and against the wall of the extension to lock said stud as seen in  FIGS. 15 b    and  16   b.    
     In this regard, a variant could be provided wherein the deformable arm includes a bump or protuberance  35   a ′ as seen in  FIGS. 19 a  and 19 b   . This bump or protuberance cooperates with lug  31 . Indeed, cleverly, lug  31  is circular but has a flat portion  31   a.  Elastic arm  35   a  is then arranged so that, when it is opposite the flat portion, said arm  35   a  is released so that the stud can be easily placed therein. When holding plate  32  is rotated to lock stud  9 , the bump of elastic arm  35   a  remains in contact with the wall of lug  31  so that the variation in thickness of lug  31  between the flat portion and the rest of the periphery thereof exerts stress on elastic arm  35   a.  This stress is intended to move the elastic arm closer to the wall of orifice  34 ,  304 . The stud is thus held in place by said elastic arm. A notch  31   b  may be envisaged on said lug  31  to lock the angular position of holding plate  32 . This configuration allows the bump to be used as a marking for viewing the angular position of the stud-holder. 
     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. 
     Further, it is possible to achieve the angular adjustment of the holding plate on the cock by providing two oblong holes on said holding plate. These two oblong holes allow the holding plate to be fixed on the cock while permitting a degree of freedom in rotation. Preferably, the oblong holes will be made such that the holding plate can be rotated about the lug. 
     Holding plate  32  could also be provided with at least one notch  32   a  on the periphery thereof, as seen in  FIGS. 19 a  and 19 b   . This notch simply allows a tool, such as a screwdriver or tweezers, to be used for rotating the holding plate. In the case of the use of tweezers, two diametrically opposite notches may be provided. 
     Likewise, lug  301  acting as a shock absorber could be used as a stop member in the Z direction for retaining the stud-holder in the event of shocks.