Abstract:
A bracelet clasp having two closing elements ( 18,20 ) arranged on the two ends of a bracelet to be joined thereby and provided with means ( 28, 40, 42 ) for the coupling thereof. A band ( 24, 60 ) is used to connect the elements and is mounted in such a way that it can be displaced in relation to both elements. Devices are provided for defining the course of band displacement in relation to the open position of the closing elements, and for associating one end of the band with one of the closing elements. The clasp also has a device for defining the course of band displacement in relation to the closed position of the closing elements, this device being arranged on a central portion of the band in relation to its length between the closing elements in their open position.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a clasp with a sliding catch designed to be fitted to a bracelet of the closed type that can be used both in watches and in jewelry but also, more generally, as any type of collar designed to be placed about a body, in a removable manner. 
       BACKGROUND 
       [0002]    Bracelets are either of the open type, when their two strands can be completely separated, or of the closed type, when the strands remain fixedly attached and are connected to one another by a clasp making it possible to increase their diameter in order to be able to put the hand through. 
         [0003]    Bracelets of this second type, to which the invention applies, most frequently use a catch, called an unfolding catch, that usually comprises a clasp with two bands articulated in butterfly fashion. In the closed position, the bands are kept folded over one another. Actuating the clasp allows them to unfold and therefore enlarge the bracelet. 
         [0004]    Certain less frequent embodiments of bracelets of the closed type use a catch, called a sliding catch, as proposed in document GB 680 368. The catch then comprises a flexible band mounted fixedly in one of the two strands by its first end, and slidingly in the other strand by its second end. Such a rather rudimentary structure certainly prevents the complication of an unfolding catch, but it does not guarantee that the two strands will remain joined when a considerable force is applied to the bracelet which may therefore open inadvertently. 
         [0005]    Document GB 1 261 027 proposes a bracelet with a sliding catch whose flexible band also slides in only one strand of the bracelet by one of its ends. However, this device does not have the abovementioned disadvantage because this end is furnished with two fingers forming a Y, these fingers preventing the band from coming right out of the strand in which it is lodged. 
         [0006]    However, since the band slides in only one strand, it is difficult to envisage that the conditions of sliding inside the band can be appropriate over a great length, because the flexing that the band sustains causes major friction between it and the bracelet. In addition, the bracelet, necessarily being hollow and rigid to allow the band to slide, is not very comfortable for the wearer. Actually, such a device cannot be adapted to flexible bracelets made of leather, rubber or even of metal with articulated links. 
         [0007]    The object of the present invention is therefore to propose an enhanced version of a bracelet clasp with a sliding catch, free from the abovementioned disadvantages and adapting to any type of bracelet. 
       SUMMARY OF THE INVENTION 
       [0008]    More precisely, the invention relates to a bracelet clasp with a longitudinal axis Y-Y, comprising:
       two closing elements respectively designed to be placed at the two ends of the bracelet that are to be joined, and furnished with means for them to be coupled; and   a band connecting said elements and mounted so as to be able to move in relation to each of them,   members for limiting the travel of the band in the open position, in relation to said closing elements, associating one end of the band with one of the closing elements.       
 
         [0012]    According to the invention, the clasp also comprises a member for limiting the travel of the band in the closed position, in relation to said closing elements, placed on said band, at its central portion in relation to the longitudinal axis, in the travel of said closing elements. 
         [0013]    According to a first embodiment of the invention, the clasp is characterized in that the band is mounted so as to slide in each of the two elements, the elements being arranged to receive it. 
         [0014]    As a variant, the band is made in two portions formed so as to nest telescopically in one another, each being fixedly attached to one of the closing elements but capable of sliding in the other. 
         [0015]    In another embodiment, the band is furnished with a first guide. The closing elements each comprise a skid interacting with this first guide to allow the relative movement of the elements and of the band. 
         [0016]    In another particularly advantageous variant, the band is furnished with a first guide, the clasp comprises first and a second slide-blocks moving in this first guide on either side of the member for limiting the travel of the band in the closed position. The first and second slide-blocks each form a second guide. The closing elements each comprise a skid interacting respectively with the second guide of the first and second slide-blocks, to allow the relative movement of the elements and of the band. 
         [0017]    The invention also relates to a bracelet that is flexible or has articulated links furnished with a clasp as defined above. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    Other features will emerge from the following description given with reference to the appended drawings in which: 
           [0019]      FIG. 1  is a view in perspective of a bracelet fitted with the clasp according to the invention, in the open position; 
           [0020]      FIG. 2  is a top view in section along AA of the clasp in the closed position; 
           [0021]      FIG. 3   a  is an enlarged plan view of its operating mechanism, while 
           [0022]      FIG. 3   b  shows it seen from above; 
           [0023]      FIGS. 4 ,  5 , and  6  illustrate various embodiments of the clasp; 
           [0024]      FIGS. 7 to 10  present various views of a particularly advantageous embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    A bracelet having a clasp comprising a sliding catch according to the invention, in the open position, is represented in  FIG. 1  showing only that it comprises two strands  10  and  12 . It is understood that, for a watch application, it effectively involves two separate strands whose respective ends  14  and  16  are suitable for being connected to a watch case by any method known to those skilled in the art. On the other hand, for a jewelry application, the bracelet may comprise either a single strand, or two strands joined by a central articulation. The bracelet represented has links, but it may be monobloc, particularly made of synthetic material. 
         [0026]    The invention relates essentially to the clasp that makes it possible to couple the ends of the bracelet opposite to the ends  14  and  16 . 
         [0027]      FIGS. 1 and 2  show that the two strands  10  and  12  are attached, by their respective ends, to two elements  18  and  20  that form the actual clasp of the bracelet and have the same outer, generally parallelepipedal shape. The material used can be chosen by the manufacturer from all the materials known in the field, such as titanium, steel, platinum, ceramic or a synthetic material. 
         [0028]    Each of the elements  18  and  20  comprises a front portion designed to join the front portion of the other, and a rear portion to which the end of a strand of the bracelet is attached. 
         [0029]    The element  18  forms the active half of the clasp. Its front portion  18   a  has a thin rectangular channel  22  in which a flexible or rigid band  24  can move freely, advantageously made of steel, carbon, kevlar, plastic, gold or platinum and described in detail below. The rear portion  18   b  forms a housing in which one end of the bracelet may be attached by screws, by a bar or by any other means available to those skilled in the art. 
         [0030]    The element  20  forms the passive half of the clasp. Its front portion  20   a  has a thin channel  26 , identical to the channel  22 , in which the band  24  can also move freely. The rear portion  20   b  forms a housing in which the other end of the bracelet may be attached in the same manner as mentioned above. 
         [0031]    The band  24  then penetrates, via its ends, the two strands  10  and  12  of the bracelet that must therefore be arranged to receive it and allow it to slide freely. 
         [0032]    To allow the coupling of the two elements of the clasp, the active element  18  receives, in its front portion  18   a , two pushbuttons  28  aligned face to face along a transverse axis XX perpendicular to the longitudinal axis YY of the bracelet and lodged in openings made in the side faces of the body  18 . An O-ring  30  serves to prevent the accumulation of dirt in the element  18 . 
         [0033]    As also shown in  FIG. 3 , the pushbuttons  28  each serve to actuate a claw  32  formed of a semi-tubular body  34  capable of moving along the axis XX in a cylindrical housing  36  with an axis parallel to YY. The pushbutton  28  acts on the middle of the outer face of the body  34 . This serves as a cradle to a circular leaf spring  38  open on the side opposite to the pushbutton and extends, outside the housing  36 , via a hook  40  coming out of the front face of the element  18 . 
         [0034]    On its side, the passive element  20  of the clasp has, in its front face, two housings  42  shaped and dimensioned to receive the hooks  40  of the active element  18 . 
         [0035]    In order to make it easier to couple the two halves of the clasp, the element  18  has, on its front face, two guide pins  44  taking position in housings made in the front face of the element  20 . 
         [0036]    Thus, to couple the two halves of the clasp, it is sufficient to bring them face to face, with the aid of the guide pins  44 . The simultaneous actuation of the two pushbuttons  28  then makes it possible to compress the leaf springs  38  against the wall of the housings  36  and thereby to move the claws  32  inward, so as to allow their hooks  40  to penetrate the housings  42 . Releasing the pushbuttons  28  causes the springs  38  to return to their rest position while moving the claws  32  outward, so that the hooks  40  fasten to the element  20  in the housings  42 . The bracelet is thus closed and locked. 
         [0037]    Conversely, to open the bracelet, it is sufficient to again push in the two pushbuttons  28  which, by compressing the springs  38 , make it possible to release the hooks  40  from their housings  42 . The two halves of the clasp may then be separated. 
         [0038]    Reference will now be made to  FIG. 4  which represents a first possible embodiment of the clasp according to the invention, the strands of the bracelet not being shown. This figure, like the subsequent figures, will contain the elements already described, assigned the same reference numbers. 
         [0039]    The band  24 , that is now shown over its full length, is flat and terminates, at its two ends, in a curved portion  46  that butts against the entrance of the channel  22  or  26  respectively of the element  18  or  20 , and cannot penetrate it, thereby limiting the travel of the two halves of the clasp (that is to say the opening of the bracelet) and preventing the latter from separating from the band. The latter has, in its middle, a rivet  48  (also visible in  FIGS. 1 and 2 ) which, like the curved end portions  46 , cannot penetrate the channels  22  and  26 , thereby ensuring the same travel for each half of the clasp. 
         [0040]    The curved portions  46  and the rivet  48  are only examples of means for limiting the travel of the two halves of the clasp relative to the band  24 . Any other system having the same effect can naturally be used in the context of the invention. 
         [0041]    The band  24  shown in the figures previously described is flat, but it could also, as shown in  FIG. 5 , be shaped lengthwise and widthwise in any manner that would make it more or less rigid and/or more or less light, particularly by means of cutouts  50  and side ribs  52 . 
         [0042]    Finally, in the clasp of  FIG. 6 , the band  24  is made in two portions  24   a  and  24   b  shaped so as to nest telescopically in one another. In this case, the half-band  24   a  is fixedly attached to the element  18  but can slide in the element  20  to occupy, at the end of travel, when the bracelet is fully closed, the position shown in dashed lines. Symmetrically, the half-band  24   b  is fixedly attached to the element  20  but can slide in the element  18  to occupy, at the end of travel, the position shown in dashed lines. 
         [0043]    An embodiment shown in  FIGS. 7 to 10  uses the principle of a band formed of telescopic elements. This clasp with sliding catch not only has the advantages of the embodiments described above but also makes it possible, in a very advantageous manner, to be adapted to any type of flexible bracelet made of leather, rubber or even metal with articulated links. Specifically, as will be better understood hereinafter, the bracelet does not have to be arranged particularly to receive the flexible band. 
         [0044]    Therefore, in a more detailed manner, the band of the clasp according to this particular embodiment has the shape of a central plate  60  whose longitudinal edges, that is to say parallel with the axis Y-Y, form a first guide  62 . 
         [0045]    In this version also, the device is furnished with members for limiting the travel of the band, making it possible to define either the closed position or the open position of the clasp. A first rivet  64  for limiting the travel of the band in the closed position is placed in the central portion of the plate  62 , advantageously in the middle of it with reference to the length of the latter. A second rivet  65 , for limiting the travel of the band in the open position, is placed at a first end of the plate. This rivet can be seen in  FIGS. 8 to 10 . 
         [0046]    A first slide-block  66  is formed of a shaped element similar to the band  24  as described above concerning the embodiment of  FIG. 5 . This slide-block  66  has the shape of a frame whose longitudinal edges  66   a  are adapted and dimensioned to slide without clearance in the first guide  62 . 
         [0047]    The height of the first rivet  64  is adjusted so that it interacts with the outer wall of the transverse edge  66   b  of the frame, situated on the side of the rivet  64 . This wall is furnished with a housing  68  of semicircular shape, capable of receiving approximately half of the rivet  64 . 
         [0048]    The rivet  65  is situated inside the frame  66 . In practice, the rivet is clinched after the frame has been correctly positioned. Its height is also adjusted so that it interacts with the inner wall of the transverse edge  66   b  of the frame  66 . 
         [0049]    In addition, the longitudinal edges  66   a  of the frame are dimensioned to form a second guide. 
         [0050]    Finally, as above, the clasp comprises a first element  18  and a second element  20  forming the actual clasp. The element  18  has a generally parallelepipedal shape and comprises pushbuttons  28  making it possible to actuate the locking hooks  40 . In addition, at its base, the element  18  is furnished with a skid  70 , more easily visible in  FIGS. 9 and 10 , dimensioned and shaped to slide without clearance in the second guide. The skid  70  is furnished, under it, with a pin  72 , visible in  FIG. 10 , dimensioned to interact with the inner wall of the transverse side  66   b  of the frame, without hampering the sliding of the skid. 
         [0051]    The height of the rivet  64  is adjusted so that it interacts also with the element  18  for limiting its travel in the closed position. Therefore, the skid  70  has a housing situated on the side of the rivet  64 , in which the latter takes position and abuts, when the clasp is in the closed position. 
         [0052]    Since the pins  65  and  72  are both designed to interact with the wall  66   b , they are situated in one and the same plane X-Y. However, they are offset from the transverse axis X-X so that they cannot collide during relative movements of the slide-block  66  and the element  18 . 
         [0053]    Symmetrically relative to the middle of the plate  60  and the rivet  64 , the clasp comprises another slide-block  80  similar to that described above and bearing reference number  66 . The element  20 , having housings  42  to receive the hooks  40  of the element  18 , slides in this slide-block  80  thanks to a skid  82  with which it is furnished, similar to the skid  70 . The rivet  64  also serves as a travel limiter in the closed position and is capable of taking position in a housing made in the outer wall of the transverse edge  66   b  of the frame forming the slide-block  80 . 
         [0054]    The elements placed symmetrically are also furnished with members for limiting the travel of the band, similar to those referred to above. 
         [0055]    Thus, in the closed position, the elements  18  and  20  are pressed onto the rivet  64  and are in contact with one another, the hooks  40  interacting with the housings  42 . The outer walls of the transverse edges of the slide-blocks  66  and  80  also press on the rivet  64 , the pin  72  of the skids  70  and  82  of the elements  18  and  20  pressing on the inner walls of the transverse edges of the slide-blocks  66  and  80 . 
         [0056]    In the open position, the slide-blocks  66  and  80  are pressed by the inner wall of their transverse edge  66   b  and  80   b  onto the pin  65 . The elements  18  and  20  are, for their part, pressed by the pin  72  of their skid onto the inner walls of the transverse edges respectively opposite to the edges  66  and  80   b.    
         [0057]    As illustrated in  FIG. 7 , the clasp that has just been described may receive a flexible bracelet made of leather or rubber for example. A first strand  10  of the bracelet is attached, by one of its ends, to the element  18  by means of screws  84  or by a bar. 
         [0058]    To receive and attach the second strand of the bracelet, the element  20  is furnished with a catch  86  defining a frame and mounted by two screws  88  so as to pivot on the element  20 . The catch is dimensioned to allow the bracelet to move flat inside the frame. 
         [0059]    This frame is furnished with a stud  89  designed to lodge in one of the holes with which the bracelet is normally furnished, in order to allow, in a completely conventional manner, the adjustment of its length. The catch  86  is arranged so that, once the stud  89  is positioned in the appropriate hole of the bracelet, a pull on this bracelet does not cause the catch to pivot. 
         [0060]      FIG. 9  represents the clasp according to this embodiment adapted to a metal bracelet with articulated links, whose ends are mounted directly, in a conventional manner, on the elements  18  and  20 . All the telescopic elements of the clasp take position beneath the bracelet, so it is not necessary for the latter to be arranged particularly to receive a sliding portion of the clasp. 
         [0061]    In a simplified variant, those skilled in the art will be able to produce a clasp that comprises, for each of the elements  18  and  20 , only one sliding element, that is to say that the slide-blocks  66  and  80  may be deleted. In this case, the skids  70  and  82  slide directly in the guide  62  of the plate  60 . The latter may terminate, at its ends, in rims forming stops and limiting the travel of the elements  18  and  20  in the open position. 
         [0062]    In this way, a bracelet clasp with a sliding catch is proposed that does not suffer from the complexity of clasps with an unfolding catch. The clasp according to the invention is both of simple construction and furnished with a totally invisible catch. 
         [0063]    The rivets  64  or  48  serve as travel limiters in the closed position and make it possible to distribute, on one side and the other relative to the elements  18  and  20 , the length of the sliding elements. It is therefore possible that these rivets are not exactly in the center of the clasp, although the distribution of the sliding elements is satisfactory in the closed position.