Patent Publication Number: US-2023141715-A1

Title: Assembly of a wristband to a watch case

Description:
This application claims priority of European patent application No. EP21206678.1 filed Nov. 5, 2021, the content of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND ART 
     The invention concerns a device for fixing a wristband to a watch middle. It also relates to a timepiece as such comprising at least one such fixing device, in particular a wristwatch, in which the fixing device is arranged between a wristband and a middle of the timepiece. 
     Various devices are used to fix a wristband in a removable and articulated manner to a middle of a wristwatch. For example, in accordance with a routine solution of the prior art a watch middle has two pairs of lugs, each pair of lugs delimiting a housing to receive a link arranged at the end of a wristband. A pin extending between the two lugs of a pair of lugs comes into engagement with this link of the wristband, retaining it in position between these two lugs, whilst enabling relative articulation of the wristband and the watch case by pivoting about this pin. 
     This way of fixing a wristband to a watch case, in particular to a middle, must ideally achieve the following objectives:
         It must be reliable, more particularly to prevent any unintended detachment of the wristband;   It must be robust, and in particular prevent any wear that would deteriorate its functionality over time;   It must enable user-friendly removal and fixing of a wristband, for example enabling its easy and rapid replacement;   It must have an attractive esthetic appearance, and in particular must be compatible with the esthetic requirements of top of the range timepieces.       

     SUMMARY OF THE INVENTION 
     Existing solutions achieve at least some of the foregoing objectives but remain open to improvement. Thus an objective of the present invention is to improve on this situation. 
     Thus a general object of the invention is an improved solution for fixing a wristband to a watch middle, more generally to a watch case. 
     To be more precise, a first object of the invention is a reliable and robust solution for fixing a wristband to a watch case. 
     A second object of the invention is a user-friendly solution for fixing a wristband to a watch case. 
     A third object of the invention is preferably an esthetic solution for fixing a wristband to a watch face. 
     To this end the invention is based on a device for fixing a wristband to a watch middle, comprising a connecting element intended for connection to a wristband or to a watch middle, respectively, at least one pin able to occupy two positions, a position projecting from the connecting element and a position retracted into a housing of the connecting element, and a receiving element intended for connection to a watch middle or to a wristband, respectively, comprising at least one bore, and wherein the fixing device comprises at least one insert, the fixing device being designed to occupy at least two configurations:
         a first configuration in which the at least one pin occupies a position retracted into the connecting element, enabling a wristband to be separated from a watch middle, and   a second configuration in which the at least one pin occupies a position projecting from the connecting element and is positioned in the at least one bore of the receiving element, the at least one insert forming an interface between said at least one pin and said at least one bore and/or said housing to minimize frictional wear on rotation of said at least one pin relative to the receiving element and/or to the connecting element, respectively.       

     The invention is more precisely defined by the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These objects, features and advantages of the present invention will be explained in detail in the following description of one particular embodiment given by way of non-limiting example and with reference to the appended figures, in which: 
         FIG.  1    represents an exploded perspective view of the device in accordance with one embodiment of the invention for fixing a wristband to a watch middle. 
         FIG.  2    represents a partially truncated perspective view of a device in accordance with the embodiment of the invention for fixing a wristband to a watch middle in a configuration for fixing the wristband. 
         FIG.  3    represents a perspective view of the fixing device in accordance with the embodiment of the invention including pins in retracted position. 
         FIGS.  4  to  7    represent views from above of variant embodiments of the fixing device in accordance with the embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS 
     To simplify the description of the invention corresponding or identical elements in different variant embodiments bear the same references. 
     The invention is therefore based on a device for fixing a wristband to a watch middle, more generally to a watch case. This fixing device comprises two complementary main elements, namely a connecting element and a receiving element, respectively arranged on a wristband and on a watch case, or vice-versa. These connecting and receiving elements are intended to be removably fixed to one another, as will be explained hereinafter. 
       FIGS.  1  to  3    show an embodiment of the invention in which a connecting element  11  takes the form of a wristband link forming a connecting link. This connecting link is intended to be disposed at the end of a wristband  10 . It advantageously has the same shape and the same appearance as the other wristband links. 
     In this embodiment the fixing device further comprises a receiving element  21  that takes the form of two substantially parallel lugs arranged face to face on a middle  20 . Each lug comprises a bore  21   a  that in particular takes the form of a blind hole. The respective bores  21   a  of the two lugs are arranged along axes that are preferably substantially aligned. The bores preferably have a circular cross-section. The openings of the two bores are oriented toward one another. The space between the two lugs defines a housing intended to be occupied by the connecting link of the wristband. The visible exterior surface of the lugs is not modified in any way, with no discontinuity that would come to degrade its appearance. Nevertheless, as an alternative, the two bores could feature through-holes and/or be provided with bearing surfaces and/or have orientations that are not parallel to one another. 
     The fixing device further comprises two pins  1  intended to fix or not to fix the connecting element  11  to the receiving element  21 . Each pin  1  is able to occupy two positions, a position projecting from the connecting element  11 , as represented in  FIG.  2   , and a position retracted in a housing  11   a  of the connecting element  11 , as represented in  FIG.  3   , as will be explained hereinafter. 
     The fixing device is therefore designed to occupy at least two configurations:
         a first configuration in which the pins  1  occupy a position retracted into the connecting element, enabling a wristband link to be separated from a watch middle, and   a second configuration in which the pins  1  are held in a position projecting from the connecting element  11  and are positioned in the respective bores  21   a  of the receiving element  21  so as therefore to fix between them the connecting element  11  and the receiving element  21  and therefore to connect a wristband to a watch middle.       

     Each pin  1  is positioned in a housing  11   a  in the connecting element  11 . Two housings  11   a  preferably extend along the same axis A 1 . Moreover, the housings  11   a  take the form of a transverse through-hole. This hole therefore opens onto the two opposite side walls or flanks  11   b  of the connecting element. Each housing  11   a  enables a pin  1  to slide freely along the axis A 1  with one degree of freedom in movement in translation. This degree of freedom in movement in translation enables the pins  1  to be positioned so as to project from or to be retracted into the flanks  11   b  of the connecting element  11  so as to enable assembly and demounting of the connecting element  11 , respectively. As an alternative, each of the housings  11   a  could take the form of a blind hole opening onto the flanks  11   b  and/or be provided with bearing surfaces. 
     The connecting element  11  further comprises a recess  2   a  extending from a wall of the connecting element  11  and opening into at least a part of the housings  11   a  of the pins so that the pins  1  can be manipulated by an operator in this recess  2   a . In this embodiment an attached element  2  that takes the form of a cover is intended to be placed in the recess  2   a . When it is positioned in this recess the attached element  2  cooperates with the pins  1 , as will be described hereinafter. A fixing element  4  such as a screw enables the attached element  2  to be fixed in the housing  2   a  of the connecting element  11 . To this end the connecting element  11  comprises an internal screwthread  4   a . The attached element  2  is preferably demountable. Moreover, the attached element  2  advantageously has a shape complementary to that of the recess  2   a , in particular a volume corresponding or substantially corresponding to that of the recess  2   a , so that when it is fixed to the connecting element  11  its visible surface espouses (or conforms to) the adjoining surface of the connecting element  11  and/or of the receiving element  21  to form a substantially continuous surface. By virtue of this arrangement the attached element  2  may be conformed to the fixing device and optimize the esthetic appearance of the connecting element  11  and/or of the receiving element  21 . In addition, the attached element  2  is preferably disposed on the side of the connecting element  11  that cannot be seen. For example, it is provided on the face of the connecting link intended to come into contact with the wrist of the wearer. As an alternative the attached element may take some other form, and may in particular project from the connecting element  11  and/or from the receiving element  21 . In a further variant it may be fixed to the connecting element by any other means, such driving it in, gluing it, clipping it, welding it, brazing it, etc. It is therefore not necessarily removable, in which case the wristband will not be demountable once fastened to a middle. As will be explained hereinafter, in another variant the attached element may consist of a plurality of parts and/or be disposed in the receiving element  21 . Consequently, the recess  2   a  may also consist of a plurality of parts and/or be disposed in the receiving element  21  in at least parts of the housings  21   a  of the pins. Of course, the fixing means of the attached element or elements will need to be adapted and/or rearranged accordingly in the receiving element. 
     In this embodiment each pin  1  has exactly the same shape and is arranged in a symmetrical manner in the connecting element  11 . This connecting element  11  has a shape that is substantially symmetrical with respect to a median plane perpendicular to the axis A 1 . Each pin  1  has a cylindrical central portion, a first functional portion oriented toward the exterior of the connecting element  11 , which has a cylindrical shape, and a second functional portion oriented toward the interior of the connecting element  11 , which has a plurality of functional surfaces. The first and second portions of each pin  1  are arranged on respective opposite sides of the central portion. Each pin  1  is mobile in translation in a housing  11   a  of the connecting element so that it is able to occupy a projecting position in which at least first portion projects from the flank  11   b  of the connecting element and is therefore able to take up its place in a bore  21   a  of the receiving element  21 . The first portion is thus intended to form a pivot  1   a  about which the receiving element  21  is mobile in rotation relative to the connecting element  11 . 
     Each pin  1  further comprises functional surfaces in its second portion opposite the first portion. In particular, the first internal end of each pin  1  in this second portion forms an abutment surface or stop  1   b . The attached element  2  comprises at least one first surface that defines an axial first abutment or stop  2   b  intended to cooperate with this stop  1   b  of each pin  1  in order to hold it in position projecting from the flanks  11   b  of the connecting element  11  when the attached element  2  is fixed to the connecting element  11 . In other words, when the attached element  2  is fixed to the connecting element  11  its first surfaces come into engagement with the stop  1   b  of each respective pin  1  in the projecting position, thus preventing the pins  1  from moving so as to retract from the flanks  11   b  of the connecting element  11 , with the result that the pins  1  continue to project. 
     Additionally, the second portion of each pin  1  comprises a non-cylindrical portion  1   c  that is intended to cooperate with a complementary portion  3  of the attached element  2  visible in  FIG.  2    so as to prevent any rotation of a pin  1  about the axis A 1  in the presence of an attached element  2 . In the embodiment shown the non-cylindrical portion  1   c  of the pins  1  has a triangular section formed of three surfaces  1   d , one or the other of these surfaces being intended to cooperate with the complementary portion  3  of the attached element  2 , which thus forms a second abutment  3  preventing rotation of each of the pins  1 . This rotation second abutment  3  in the attached element  2  therefore makes it possible to immobilize each pin  1  in rotation relative to the connecting element  11 . The non-cylindrical portion  1   c  could alternatively for example have a square, three-lobe or half-moon section. Alternatively the rotation second abutment  3  of the pins  1  could also be arranged in the connecting element  11  and not on the attached element  2 . In a variant of this kind the rotation second abutment of the connecting element could cooperate with the pins  1  only in their projecting position or alternatively also in their retracted position. In a further variant the rotation second abutment  3  of the pins  1  could also be arranged in the bores  21   a  so that it cooperates with the pins  1  only in their projecting position. Moreover, the different functional portions of the pin  1  could be arranged in any other manner enabling fixing in accordance with the invention. For example, in another design variant the stop  1   b  could be on the same portion as the pivot  1   a , opposite another portion where the non-cylindrical portion  1   c  would be situated. Of course, this example is not limiting on the invention. Some of the possible variants will be specified hereinafter. 
     To summarize, in this embodiment, in the absence of the attached element  2 , each pin  1  has two degrees of freedom relative to the connecting element  11 : a movement in translation along the axis A 1  and a rotation on itself about that same axis A 1 . The fixing of the attached element when the pins  1  are in their position projecting from the connecting element  11  enables these two degrees of freedom to be eliminated, the pins  1  then remaining immobilized in their projecting position and no longer being able to turn on themselves in the housings  11   a  of the connecting element  11 . 
     The operation of the fixing device in accordance with the embodiment of the invention will now be explained. When the device is in its fixing configuration, as shown in  FIG.  2   , an operative can remove the attached element  2  by unscrewing the screw  4 . They thus gain access to the recess  2   a  in the connecting element and to the second functional portions of the two pins  1  disposed at least partly in this recess. The operative can then move the pins in translation to move them inside the recess  2   a  from their projecting position to their retracted position. To assist this operation each pin  1  preferably comprises a notch or a groove if at the level of its second functional portion, which enables the insertion of a simple tool, such as a pin or tweezers, to guide the retraction movement in translation of the two pins manually. Of course, any other means or tools enabling actuation of the two pins may be envisaged, such as magnets, for example. When this operation is completed the first functional portions of each pin  1 , in particular their pivots  1   a , are housed in the connecting element  11  and free of the bores  21   a  in the receiving element  21 . The connecting element  11  can then be detached from the receiving element  21 . The reverse operation enables the two elements to be fastened together. 
     To reduce frictional wear surfaces of the articulation relative to the connecting and receiving elements the pins  1  and/or the receiving surfaces of the receiving element  21  and/or the receiving surfaces of the connecting element  11  receiving the pins  1  may preferably be made of a material for limiting frictional wear, such as a sintered ceramic, advantageously based on zirconia. 
     Nevertheless, in accordance with the embodiment, it is required to be able to make the middle, including its lugs, and therefore the receiving element  21  and/or the connecting element  11  of metal, in particular of a precious metal, such as gold or platinum, to be able to obtain the required esthetic finish. Similarly, the pins may be made of steel or of precious metal. Of course, other materials may be envisaged, such as composite materials. 
     For this reason the invention uses inserts  5  that form an interface at the friction surfaces of the fixing device. In the embodiment described this friction surface is positioned at the interface between the pivots  1   a  formed in the first portion of the pins  1  and the bores  21   a  of the receiving element. In this embodiment the inserts  5  therefore preferably take the form of a tube or a bearing. They may or may not be fixed into the bore  21   a . Alternatively, they may or may not be fixed to the first functional portion of the pins  1 . In another variant design said friction surfaces could be positioned at the interface between the housings  11   a  and the pins  1 , for example between the pivots  1   a  and the housings  11   a  of the connecting element. In this variant the inserts could optionally be fixed in the housing  11   a . Alternatively, they may optionally be fixed to the pins  1  in their zone rubbing (of friction) on the housings  11   a.    
     An insert may advantageously be made of a sintered ceramic or of a composite material, formed for example of a mixture of a ceramic and a metal, or a polymer (a thermoplastic for example). An insert may be made entirely or partly from a material of this kind. For example, a material of this kind may form a simple coating. An insert  5  advantageously has a hardness greater than or equal to 800 HV. 
     Moreover, in the embodiment described the pivots  1   a  formed in the first portion of the pins  1  comprise a bearing surface defining an axial abutment  1   e  between said pivots and the inserts  5  so as to prevent contact and consequent wear between the flanks  11   b  of the connecting element  11  and the lateral walls  21   b  of the receiving element  21 . 
     The invention is naturally not limited to the precise geometry of the various elements represented. Thus the pivot  1   a  of a pin  1  could have other shapes enabling the articulation of the two elements of the fixing device. For example the pivot  1   a  could be conical or truncated conical. Of course, the geometry of the inserts  5  could be adapted accordingly and therefore be complementary to the geometry of the pins. 
     In the embodiment described the pins are preferably constrained to rotate with the connecting element  11  so that the friction surfaces of the articulation are localized at the contacts between the pins  1  and the bores  21   a  of the receiving element and more particularly between the pins  1  and the inserts  5 . Of course, the opposite is also possible, with the pins constrained to rotate with the receiving element  21  so that the friction surfaces of the articulation are localized at the contact between the pins  1  and the housings  11   a  of the connecting element and more particularly between the pins  1  and the inserts  5 . 
     The invention is not limited to the embodiment described and may incorporate numerous variants. To this end,  FIGS.  4  to  7    represent a few variant embodiments of the invention for which only the specific features of those variants are described. 
     For example, as described above an attached element  2  may take different forms.  FIG.  4    thus represents a view from above of an embodiment that corresponds to the embodiment described above with reference to  FIGS.  1  to  3    in which the attached element  2  occupies a large area of the connecting element  11 . 
     Alternatively, the pins  1  may be prevented from rotating relative to the receiving element  21 , the connecting element  11  then being mobile in rotation relative to the pins  1 . In a variant of this kind the inserts  5  form an interface between the pins and the connecting elements, as represented by the variants from  FIGS.  6  and  7    described hereinafter. The inserts  5  are therefore housed in the connecting element  11 . Moreover, the pins may for example comprise non-circular first portions, for example similar to the non-cylindrical portion  1   c  described above, intended to be housed in a receiving element  21  in the projecting configuration. In particular the pins  1  could equally have a geometry substantially reversed with respect to the pins described above, the first portion forming a pivot being housed inside the housing of the connecting element, the non-cylindrical portion being oriented toward the exterior of the connecting element, intended to occupy a projecting position in a receiving element in a fixing configuration. As a further alternative the portion of the pins forming a pivot may correspond to the central position of the pins.  FIG.  7    shows one such embodiment diagrammatically. 
     In accordance with a further variant an attached element could be provided on a receiving element to cooperate with a pin at the level of the receiving element. This cooperation may consist in blocking at least one degree of freedom of said pin, for example in movement in translation, to retain it in the projecting position, and/or in movement in rotation. In one variant a single attached element or a plurality of attached elements could cooperate with the connecting element and/or the receiving element. For example, a first attached element could comprise an axial first abutment and a second attached element could comprise a rotation second abutment. These first and second attached elements could be arranged in the connecting element and in the receiving element, respectively, or vice-versa. 
     For example, in this variant an attached element can therefore be fixed to each of the lugs of the middle  20 .  FIG.  5    shows a variant of this kind in which each facing lug of the middle comprises an attached element  2  removably mounted on each lug and arranged to cooperate with a pin so as to maintain its position projecting from a connecting element, that is to say to prevent its movement in translation of retraction into the connecting element. In this variant shown in  FIG.  5    each pin  1  is immobilized in rotation relative to the connecting element by said connecting element, by means of a rotation second abutment  3 , when it is at least in its projecting position, the rotation of each lug relative to each pin being achieved by means of an insert housed in each lug. 
     In a further variant, the receiving element arranged on the middle could not have the shape with two lugs, but for example the shape of a single lug. In this variant the connecting element  11  arranged at the end of the wristband could take the form of two complementary and distinct lateral elements each incorporating a pin  1 , these two pins  1  being destined to come into position on either side of the single lug to fix a wristband onto a middle.  FIG.  6    shows this kind of embodiment in a fixing configuration. An attached element  2  is arranged on the receiving element in the form of a single lug and each lateral element of the connecting element comprises a projecting pin extending in a bore of the single lug. The attached element  2  immobilizes these pins in their projecting position and in rotation relative to the receiving element. Each lateral element of the connecting element remains mobile in rotation relative to its respective pin and incorporates an insert  5  between the pin  1  and the housing receiving it. Finally, the middle can therefore comprise at least one lug, in particular one or two lugs. Any other middle architecture can be envisaged, in particular one comprising an element of the fixing device of the invention that does not necessarily take the form of one or more lugs. 
     In another variant the fixing device may comprise one pin  1 . The fixing device thus comprises at least one pin. In another variant the at least one pin is not mobile in translation relative to the connecting element. In fact, it can be moved between its retracted position and its projecting position by any other movement, for example a rotation, or a combination of movements in translation and rotation. Additionally, it may finally be moved with one, two or more degrees of freedom relative to the connecting element, that or those degrees of freedom possibly being reduced in its projecting position. 
     As mentioned above, in accordance with one embodiment the connecting element is disposed at the end of a wristband. When the latter comprises an assembly of links, in particular metal links, the connecting element advantageously takes the form of a connecting link that has a shape identical or similar to that of other links of the wristband to give a continuous esthetic appearance. In a variant embodiment the wristband may be made of a flexible material, for example leather. In this case the connecting element can be integrated into the end of the flexible wristband, preferably in a manner that is totally or partly concealed. Alternatively, it may take the form of a metal end-piece arranged at the end of the flexible wristband. 
     In a further variant the connecting element is disposed on a watch case, in particular on a middle, and a receiving element is disposed on a wristband. For example the construction of the fixing device of the variants illustrated by  FIGS.  4  to  7    could be reversed. That is to say, in all of those figures the receiving element  21  could be a link and the connecting element  11  could be one or more lugs of a middle. 
     In all the variants described an insert could be positioned between the same pin and both the connecting element and the receiving element, an insert thus being able to surround the pin in whole or in part. A variant of this kind enables the best reduction of wear. 
     In a complementary way, in all the variants the attached element may comprise a means for acting on a pin during positioning thereof in a recess and/or during its retraction from the connecting member and/or from the receiving member so as to drive said pin in translation to move it automatically from its retracted position to its projecting position and/or vice-versa. 
     In all variants, the attached element is advantageously removable. Advantageously also, the fixing device is in the first configuration enabling a wristband to be separated from a watch middle when the attached element is removed, and the fixing device is in the second configuration when the attached element is fixed to the device. 
     In all variants, the pin is preferably made of ceramic, particularly in sintered ceramic, advantageously based on zirconia. 
     The invention also relates to a timepiece as such, in particular a wristwatch, comprising at least one fixing device as described. A fixing device of this kind is advantageously disposed on each side of the watch case, in particular of the middle, for the removable fixing of each end of the wristband.