Patent Publication Number: US-6714400-B2

Title: Link for watch bracelet

Description:
The present invention concerns a link, provided for connecting a bracelet to a watch case, the latter including an exterior or decorative element which defines at least partially its limits in the longitudinal direction of the bracelet, the exterior element being obtained by a method including a sintering step. 
     The invention concerns more generally the field of watch bracelets partially made of hard materials, such as ceramics, intended to be assembled on watches whose case includes exterior parts made of a hard material. 
     A bracelet of this type, including a more or less flexible inner structure assuring the function of a core or frame and at least partially covered by decorative elements is known to those skilled in the art. 
     American U.S. Pat. No. 5,365,753 discloses a bracelet, in particular for a watch, including an inner chain formed of articulated links, connected to each other by hinges. Each of these links, formed of two structural elements, is covered by an exterior decorative element made of ceramic material. Further, each link includes means for holding the corresponding decorative element so as to obtain an advantageous aesthetic effect, insofar as the various hinges connecting the links to each other are never visible. 
     However, this structure has certain limits in its application, as do generally known bracelets of this type in the prior art. Indeed, the decorative parts made of hard material, for example, ceramic material, are obtained by methods including a moulding step followed by a sintering step. During this sintering step, these parts undergo a contraction, i.e. a significant reduction in volume, via the combined actions of heat and pressure, this contraction being able to be more than 30% of the initial volume. Commonly implemented methods currently allow such parts to be manufactured with tolerances on the dimensions of the order of 0.5 to 1%, the sintering step making it difficult to obtain lower tolerances. It should be noted that these tolerances fluctuate as a function of the batches of raw material used. 
     The tolerances involved result, for example, in uncertainties of the order of a fifth of a millimetre over the length of a ceramic watchcase of 3 centimetres. Insofar as this type of watchcase is in the top of the watchmaking range, such uncertainty is difficult to accept for manufacturers. 
     Consequently, the prior art provided manual machining, after the sintering step, in order to eliminate the various play existing between the ceramic elements of the exterior parts of such a watch. 
     However, faced with the increasing client demand for such products, the number of watchmaking parts including ceramic decorative elements to be manufactured has greatly increased over the last few years, making the machining steps very laborious, given the quantity of parts to be processed. Moreover, this machining step is made more difficult because of the increasing complexity of the geometry of watch cases currently being made, which makes it complicated to lock the part into a given position in order to work on it. 
     It should be noted that this problem is all the more inconvenient because the decorative parts to be manufactured are large. In particular, the aforementioned manufacturing tolerances have detrimental impact on the watchcase, whose dimensions are generally larger than those of the bracelet links. Likewise, the more the manufacturer of such timepieces wishes to make bracelet links of greater dimensions, the more difficulty he will have in making junctions between the watch case and the bracelet or between bracelet links having a satisfactory aesthetic appearance. 
     The main object of the present invention is to overcome the aforementioned drawbacks of the prior art and to improve the aesthetic appearance of existing timepieces. 
     The invention therefore concerns a link for a watch bracelet of the aforementioned type, characterised in that it includes a first hollow element provided with first means for attaching it to the bracelet, a second element one part of which is nested in the first element and carrying second means for attaching said second element to the watch case and a third exterior decorative element, secured to the first element and at least partially covering the second element on the side of the second attaching means. The link according to the present invention is further characterised in that it includes a mechanical device allowing a translation of the first element with respect to the second element in the direction of the bracelet, so as to apply the third decorative element against the decorative element of the watchcase. 
     As a result of these features, it is possible to adjust the position of the bracelet with respect to the watchcase in order to correct the problems of manufacturing tolerances. As a result of such an adjustment an uninterrupted junction is obtained between the bracelet and the watchcase, which is advantageous from the aesthetical point of view. 
     In a first embodiment, the first element is hollow and the mechanical device is housed therein in the form of resilient means, such as one of more springs or an elastomer block. These resilient means exert a return force on the first element so as to bring it closer to the second end of the second element, the latter carrying the second attaching means and extending outside the first element through an aperture made in one wall of the latter. The result obtained by applying this return force is to bring the third decorative element of the link permanently closer to the watch case, independently of the value of the watch case&#39;s manufacturing tolerances. 
     In an alternative embodiment, the volume left free by the mechanical device in the first hollow element is made impervious or sealed with respect to the external environment, as a result of the use of a particular structure and suitable sealing gaskets. This feature may be advantageously used to house various electronic components or even a battery in the first element. 
     In another embodiment, the mechanical device includes means for adjusting the position of the bracelet with respect to the watchcase. In other words, the adjustments are carried out when the bracelet is attached to the case, such that the junction is uninterrupted, and can be modified subsequently. These means may, in particular, include an adjusting screw, connected in various ways to the various elements of the link according to the present invention. 
     The screw may in fact be housed in a hole arranged in the second link element, buffers may be arranged on the screw on either side of the second element, these buffers being capable of being moved in a perpendicular direction to that of the bracelet, at least one of the buffers being provided with a screw thread. Moreover, at least one oblique guide with respect to the direction of the bracelet is arranged, for each buffer, on the wall of the first element including the aperture and/or on the first end of the second element, so that each of the oblique guides is stopped against the corresponding buffer, and that any rotation of the screw is able to modify the distance between the buffers and thus the relative positions of the first and second elements. 
     This variant advantageously allows very precise adjustment of the position of the first element with respect to the second element, and thus the position of the third decorative element with respect to the watchcase. 
     In another variant, the first and second link elements may also respectively have lateral surfaces located opposite each other which are at least partially in contact with each other, the screw passing through an aperture in the second element which has an elongated oblong section, the threaded end of the screw being housed in a tapped hole arranged through said surface of the first element whereas the head of the screw is, in the screwed in position, stopped against a face of the second element opposite said surface in contact with the first element. 
     This variant allows a lower level of adjustment precision to be obtained than that accessible with the preceding variant, but has the advantage of greater construction simplicity. 
     Another variant provides that the head of said screw is housed so as to rotate freely in the wall of said first element opposite said wall including the aperture, whereas the threaded end is housed in a tapped hole of said end of the second link element located inside said first element. 
     Thus, even if the head of the screw is not as accessible as in the preceding variants, a high level of precision can be obtained while having great construction simplicity. 
     The invention also concerns a watch bracelet as defined in claim 18 annexed hereto. 
     The wristwatch thus obtained therefore has an advantageous aesthetic appearance because of the continuity existing between the bracelet and the case. 
     Each of the links of the bracelet may also include a similar structure to that of the link forming the junction between the bracelet and the watchcase, so as to assure continuity of the junctions across the entire watch. 
    
    
     Other features and advantages of the present invention will appear more clearly upon reading the following detailed description, made with reference to the annexed drawings given by way of non limiting examples in which: 
     FIG. 1 shows a perspective view of a wristwatch including links in accordance with the prior art; 
     FIGS. 2 a  and  2   b  show a schematic cross-section of the upper plane of the first bracelet link element made in accordance with a first embodiment of the invention, said link being connected to a watch case; 
     FIG. 2 c  shows a cross-section along the line II—II of FIG. 2 a  without the watchcase; 
     FIGS. 3 a  and  3   b  show similar views respectively to those of FIGS. 2 a  and  2   c  for a second embodiment of the invention; 
     FIGS. 4 a  and  4   b  show schematic cross-sections of the median plane of the link according to the invention in two different configurations for a third embodiment of the invention; 
     FIG. 4 c  shows an enlarged perspective view of a part of the link visible in FIGS. 4 a  and  4   b;    
     FIGS. 5 a  and  5   b  show similar views respectively to those of FIGS. 4 a  and  4   b  for a fourth embodiment; 
     FIG. 5 c  shows a schematic cross-section along the line V—V of FIG. 5 a  without the watch case, and 
     FIGS. 6 a  and  6   b  show similar views respectively to those of FIGS. 4 a  and  4   b  for a fifth embodiment of the invention. 
    
    
     FIG. 1 shows a wristwatch  101  in accordance with the prior art including a bracelet  102  connected to a watch case  103 , the latter both including an inner structure, which is not visible, covered by a ceramic decorative element  104 . It will be noted in this Figure that, on either side of case  103 , play, noted d 1  and d 2 , are apparent at the junctions between said case and the first links  105  of bracelet  102 . 
     These play d 1  and d 2  originate, as mentioned hereinbefore, from manufacturing tolerances in decorative elements  104 . In the case of watch  101  shown here, the bracelet decorative elements are arranged on the inner structure in predetermined fixed positions. Consequently, dimensional variations in the various consecutive decorative elements lead to the appearance of gaps between them, which has the unfortunate consequence, from the aesthetic point of view, of leaving means  106  for attaching the bracelet onto the case visible. 
     The present invention allows the aforementioned problem to be overcome by using a link having a particular structure to establish the mechanical connection between the bracelet and the case. 
     FIGS. 2 a ,  2   b  and  2   c  show such a link  1  according to a first embodiment of the invention. Link  1  includes a first hollow element  2 , of generally parallelepiped shape, shown here with a bottom  3  in its lower part and closed by a cover  4 . By way of example, screws  5  have been provided to secure cover  4  to first element  2 , the screw heads being arranged in abutment against the cover whereas their threaded rods cooperate with tapped holes  6  of the first element. 
     First element  2  includes an aperture  7 , preferably substantially circular, at the centre of one  8  of its walls so as to allow the passage of an elongated part of a second element  9  through said wall  8 . First element  2  also includes means  10  for attaching it to the next link, of a common type, such as hinges shown in the Figures, arranged on wall  11  of first element  1  opposite said wall  8  and used in combination with a common type of bar (not shown). 
     It should be noted that the link described hereinafter could be used not only to attach a bracelet to a watchcase, as shown here, but also to form the whole of a watch bracelet. In the second alternative, it is clear that attaching means  10  can also be used to establish the mechanical connection with the bracelet attachment means, such as an unfolding buckle. 
     Second element  9  has a general elongated shape, a first of its ends  12  being housed inside first hollow element  2 , whereas the second end  13  is located outside. The first end  12  extends perpendicularly to the longitudinal direction of the bracelet, in a rectangular shape whose dimensions are slightly less than the inner dimensions of the first element. The second element further includes a rod  14 , of substantially circular section and slightly smaller than aperture  7 . Said rod  14 , starting from the centre of first end  12 , passes through said aperture  7 , as far as a region having a larger section defining said second end  13 . Second end  13  includes a bore  15  fulfilling the function of a hinge, or attaching means, capable of accommodating a bar to establish the connection of second element  9 , and thus of link  1 , to the watch case (partially schematised). 
     In the case of a bracelet wherein all the links include a structure according to the present invention, said bore can also establish the mechanical connection between the preceding link, more precisely with said attaching means  10  of the next link. 
     It should be noted that, for reasons connected with the assembly of the link, said second element includes two distinct parts the junction of which is made at rod  14  by means of a key  16  of the conventional type. This indispensable structural feature in fact allows said element  9  to be assembled through aperture  7 . 
     A particular mechanical device, according to the invention, is housed in first hollow element  2 . More precisely, two helical springs  17  are inserted, in first hollow element  2 , between first end  12  of the second element and wall  8  of the first element, on either side of rod  14 . When second element  9  is arranged such that its first end  12  abuts against wall  11  of the first element, as shown in FIG. 2 b , the springs are in a slightly compressed state. 
     The link further includes a third main element  18  which fulfils a covering or decorative function. In the example shown, this third decorative element  18  has a generally hollow parallelepiped shape and is preferably made of ceramic material. The inner dimensions of said third element  18  are substantially greater than the external dimensions of first element  2  and one of its walls  19  is entirely open, so as to be able to house said first element  2  inside third element  18 . Furthermore, the wall  20  opposite said wall  19  includes an aperture  21  of substantially greater dimensions than that of second end  13  of second element  9  so as to leave a passage free for the second element. Consequently, when link  1  is assembled, third decorative element  18  at least partially covers the first and second elements. 
     In the example shown in the Figures, the structure of link  1  is such that first element  2  is entirely covered by said third decorative element  18 . 
     It will be noted that insofar as springs  17  abut against first end  12  of second element  9 , they tend to cause a translation of said second element  9  in the longitudinal direction of the bracelet. More exactly, springs  17  exert a return force on second element  9 , symbolised by the arrows referenced F in FIG. 2 a , so as to bring second end  13  closer to first element  2 . Once the mechanical connection of link  1  to case  22  of the watch is carried out at said second end  13 , the result obtained by the operation of the structure described hereinbefore is to bring said watch case  22  and link  1  closer together, until the decorative element of case  22  and third decorative element  18  of the link are in abutment against each other. One then obtains, in such a configuration, a junction between said link  1  and said case  22 , which has no interruption, which is advantageous from the aesthetical point of view. 
     It may be noted that additional structure elements appear in FIGS. 2 a ,  2   b  and  2   c , which have been shown by way of non-limiting example. 
     In fact the interior of the first link element has been made impervious, first of all to protect the return mechanism from moisture or dust capable of coming from the external environment. One may also advantageously use the available inner volume of the first element to arrange electronic components, or a battery for example, inside said volume. For this purpose, a flat gasket  23 , visible in FIG. 2 c , is inserted between the upper surface of first element  2  and cover  4  which closes said first element. Moreover, an annular groove  24  is arranged in the wall of first element  2 , in aperture  7 , allowing an O-ring type joint to be arranged therein, visible in FIG. 2 c , assuring an impervious sealing between first element  2  and rod  14  of second element  9 . 
     Since this additional feature does not constitute the core of the invention and it is known from the prior art, it will not be described in further detail in the present application. 
     In the following detailed description, the structural elements that have already been described hereinbefore bear the same reference numbers as in FIGS. 2 a  to  2   c  in order to facilitate comprehension of the invention. 
     FIGS. 3 a  and  3   b  show a variant of the embodiment which has just been described. Indeed, the only difference distinguishing these two variants concerns the nature of the mechanical device used to exert the return force on second element  9 . It will be noted in FIG. 3 a  that springs  17  have each been replaced by a block  26  of parallelepiped shape, preferably made of rubber or any other elastomeric material. Blocks  26  are shown in a compressed state in FIG. 3 a , thus in a configuration such that they exert a return force on second element  9  so as to cause watch case  22  and link  1  to come closer together. Said blocks  26  may also not be free in first element  2 , but be integral with flat gasket  23 , as can be seen in FIG. 3 b . Thus, the stability of their position in first element  2  and thus the proper working of the mechanical return device are assured. 
     The working of the invention according to this embodiment is the same as for the previously described embodiment, as is the result obtained. 
     The following embodiments are based on a different operation to that previously described in as far as the mechanical device housed in first element  2  no longer has the function of assuring a return force onto second element  9  of link  1  but a simple adjustment. 
     In the variant shown in FIGS. 4 a  and  4   b , first and second elements have shapes different from that already described. 
     Second element  9  of link  1  is made here in a single piece including two main parts perpendicular to each other, one of which defines first end  12 , whereas the other  27  carries second end  13 . Said first end  12  has a generally parallelepiped shape wherein the two edges orthogonal to the longitudinal direction of the bracelet and located on the side of second main part  27  are truncated, so as to define two inclined planes  28 . Second main part  27  extends, from the middle of first ends  12 , in a generally elongated parallelepiped shape in the longitudinal direction of the bracelet. It includes, in proximity to said first end  12 , an aperture  29  passing through it widthways and having an oblong section. It further includes, opposite said first end  12 , a bore  15  fulfilling the function of a hinge, or attaching means, and defining the second end  13  of the second element. Said hinge  15  is capable of accommodating a bar (not shown) to establish the connection of second element  9 , and thus of link  1 , to watch case  22  (partially schematised). 
     The first element has, in its wall  8 , an aperture  7  of rectangular section whose dimensions are slightly greater than those of the second main part  27  of second element  9 . Said wall  8  further includes recesses  30  at each of its junctions with the lateral flanks  31  of first element  2 . These recesses  30  thus define inclined planes  32  whose respective angles to the longitudinal direction of the bracelet are opposite to those of the angles of inclined planes  28  of first end  12 , respectively located opposite. 
     One of said lateral flanks  31  of the first element includes a cylindrical aperture  33  whose function will be described hereinafter. 
     A screw  34  is arranged through aperture  29  of second element  9 , the head  35  of said screw being arranged facing cylindrical opening  33  to be made accessible to an operator. 
     Two buffers  36 ,  37  are arranged on said screw  34 , on either side of second element  9 . Preferably, these buffers  36 ,  37  are made of an elastomer the choice of which will not pose any problem for those skilled in the art. As visible in FIG. 4 c  showing a perspective view of buffer  36 , each of said buffers includes two parallel rectangular bases  38 ,  39  and four faces, of which two opposite faces  40  are perpendicular to said bases, the two other faces  41  being inclined with respect to the axis of the screw by an angle of the same value as said inclined planes  28  and  32  which are facing. The two faces  41  have a rectangular shape whereas the two other faces  40  are trapezoid. The buffers each further include a through hole  42 , perpendicular to said bases at their centre. 
     A first buffer  36 , located on the side of screw head  35 , also includes a cylindrical recess  43  of dimensions such that said screw head  35  can be entirely housed therein. Said cylindrical recess  43  and said through hole  42  respectively have substantially larger dimensions than those respectively of screw head  35  and rod  34 , so that a free rotation of screw  34  in buffer  36  is possible. 
     The second buffer  37  includes, in its through hole, an internal female screw thread co-operating with the threading of screw  34  and located in proximity to the end of screw rod  34 . 
     It will be noted that in order to pass from the configuration shown in FIG. 4 a  to the configuration shown in FIG. 4 b , screw  34  has been “tightened”, in other words, said screw has been rotated in the clockwise direction. Indeed, when said screw  34  is rotated clockwise, buffer  37  effects a translation to come closer to the head  35  of said screw  34 . Insofar as the position of buffer  36  is fixed with respect to said screw  34 , the translation of buffer  37  towards screw head  35  causes said two buffers  36  and  37  to come closer together. This movement towards each other is made possible by sliding the inclined faces of each of the buffers on the corresponding inclined planes  28  and  32  forming oblique guides for said buffers. Said sliding further causes first end  12  of second element  9  and wall  8  of first element  2  to move away from each other. Said movement away from each other corresponds to a movement towards each other of second end  13  of second element  9  and first element  2 , which also corresponds to a movement towards each other of link  1  and case  22 , as is shown in FIG. 4 b.    
     As a result of the operation of the mechanical device described hereinbefore, a continuous junction is obtained between link  1  and case  22  of the watch, which constitutes the desired aesthetic advantage. 
     The embodiment shown in FIGS. 5 a  to  5   c  also relies on the use of a screw  34  housed in first element  2  of link  1 . As in the preceding embodiment, said screw is arranged through an aperture  29  of the second element, of oblong section of greater width than in the preceding embodiment, and its head  35  is accessible through an aperture  33  arranged in one of lateral flanks  31  of said first element. However, in the present variant, end  44  of the threaded rod of screw  34  is housed in a tapped hole  45 , made in lateral flank  33  of the first element opposite to that including aperture  33 . 
     In order to complete the mechanical adjustment device which has just been described, it will be noted that a large part  46  of lateral flank  31  including said tapped hole  45 , close to wall  8  of the first element, has a greater thickness than the part of said flank  31  which is furthest from said wall  8 . Thus, part  46  is in contact with the side of main part  27  of the second element located on the same side when screw  34  is in the tightened position, as shown in FIG. 5 b.    
     In order to adjust the relative positions of link  1  and watch case  22 , screw  34  is loosened in a similar position to that shown in FIG. 5 a . In such a configuration, the friction forces occurring between part  46  of first element  2  and second main part  27  of second element  9  are low. Thus, a translation of first element  2  with respect to second element  9 , or conversely, is made possible. Second element  9  is then arranged with respect to first element  2  such that, when link  1  is mounted on watchcase  22 , the third decorative element  18  is flush with said case  22 . Screw  34  is then tightened until its head  35  abuts against part  27  of second element  9 , which has the effect of tightening second element  9  against part  46  of first element  2 . In this configuration shown in FIG. 5 b , the friction forces between the first and second elements  2 ,  9  are so great that a translation of one of these elements with respect to the other is no longer possible. 
     The wristwatch can then be assembled without its internal structure being visible at the junctions between case  22  and first links  1 , located on either side of said case. 
     Link  1  according to another embodiment, shown in FIGS. 6 a  and  6   b , also includes a screw  34  but arranged here in the longitudinal direction of the bracelet. The first element  2  has a simplified shape with respect to the preceding variants. Indeed, the general shape of element  2  is parallelepiped and includes a recess  47 , also of parallelepiped shape, starting from wall  8 , extending across the entire height of element  2  and most of its width. First element  2  further includes a cylindrical aperture  48  passing through first element  2  from its wall  11  as far as recess  47 . Said aperture  48  includes, from wall  11  and in the longitudinal direction of the bracelet, two portions  49 ,  50  the first  49  of which has a larger diameter than that of second portion  50  opening into recess  47 . 
     Second element  9  includes, from its first end  12 , a first portion  51  of substantially constant section smaller than the dimensions of recess  47 , followed by a second portion  52  of slightly greater section than that of said first portion and ending in second end  13 , of the same section as the first portion. Second element  9  further includes a tapped hole  53  arranged from first end  12 , in the longitudinal direction of the bracelet. 
     The third decorative element  18  includes in its wall  20  an aperture  21  of rectangular section whose dimensions are substantially greater than those of second portion  52  of second element  9 . Further, the length of said second portion  52  is substantially equal to the thickness of said wall  20 . 
     Screw  34  is arranged in link  1 , such that its head  35  and a short part of its rod are housed in cylindrical aperture  48  of first element  2 , head  35  abutting against the junction separating portions  49  and  50 . In the present variant, head  35  of said screw is accessible via open wall  19  of third decorative element  18 . End  44  of screw  34  is screwed into tapped hole  53  of second element  9 . Thus, screw  34  is free to rotate about itself without moving with respect to first element  2  whereas its degree of penetration into second element  9  can be modified by screwing or unscrewing it. 
     Consequently, when screw  34  is screwed into, respectively unscrewed from, second element  9 , its first end  12  comes closer, respectively moves away from, wall  11  of first element  2 . Insofar as second end  13  of the second element is connected to watch case  22 , the latter undergoes the same movements as those described above for first end  12 . 
     One thus obtains, via this relatively simple structure, the possibility of fine adjustment of the position of case  22  with respect to link  1 , correcting any lack of continuity between these two elements capable of occurring because of the manufacturing method used to make their respective decorative elements. 
     One may obviously envisage making, for example first element  2 , with a more complex shape, in particular by providing a hollow zone and means for making said hollow zone impervious with respect to the external environment, in order to be able to house electronic components therein. 
     The preceding description corresponds to preferred embodiments of the invention and should in no way be considered limiting, as regards more particularly the shape described for the various structural elements forming the link according to the invention. Likewise, those skilled in the art are capable of adapting the dimensions of the various structural elements without any difficulty as a function of the nature of the ceramic material employed, for example, to make the mechanical device with sufficient clearance to make continuous junctions between the various decorative elements of the watch.