Abstract:
Watch case comprising an unfolding clasp for a flexible strap, said unfolding clasp comprising: 
       a middle ( 1 ) connected to a first end of the strap,    a base ( 3 ) connected to the second end of the strap,    an extension ( 2 ), connected in articulated fashion to the middle ( 1 ) and to the base ( 3 ),    wherein the articulations ( 20, 21 ) between the middle ( 1 ) and the extension ( 2 ) and between the base ( 3 ) and the extension ( 2 ) are arranged in such a manner as to allow the middle, the extension and the base to superimpose in folded position, and to be juxtaposed in unfolded position,    a regulating cam ( 34 ) for holding by compression and/or friction the strap against the base, the cam being capable of being swung to increase or reduce in a reversible manner the length of in folded position of the strap.

Description:
REFERENCE DATA  
       [0001]     This application is a continuation of International Patent Application PCT/EP2005/050297 (WO2005/089584) filed on Jan. 24, 2005, claiming priority of Swiss patent application 2004CH-00240 of Feb. 17, 2004, the contents whereof are hereby incorporated. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention concerns a watch case including a strap clasp, in particular an unfolding clasp for flexible strap.  
       DESCRIPTION OF RELATED ART  
       [0003]     Wristwatches generally comprise a watch case that notably contain the movement, a strap/wristlet and a strap clasp allowing the strap to be opened and closed for slipping on and slipping off the watch. The clasp is most often placed at 180° of the case along the strap. There are many types of clasps for flexible or rigid straps; it must however be admitted that unfolding clasps, that allow the strap&#39;s length to be adjusted without dissociating the two ends, give greater security.  
         [0004]     Unfolding clasps generally comprise several metallic blades superimposed in folded position. If the blades&#39; curve does not correspond to the wrist&#39;s diameter, these clasps can be uncomfortable. Furthermore, contact with metal both on the wrist&#39;s upper side as on its lower side increases the risk of nickel allergies for example.  
         [0005]     Watches are also known in which the clasp is integrated in the case. The case comprises in this case several unfolding blades that are superimposed on or under the case in folded position. U.S. Pat. No. 4,748,604, U.S. Pat. No. 2,429,950 and utility model DE-U-752757 describe examples of such a clasp.  
         [0006]     CH156174 describes another wristwatch combined with a three-bladed clasp. The middle is mounted on the intermediary blade of the clasp whilst the upper blade is formed as frame by folding above this middle. This construction is complex and widens the watch. The three parts of the clasp are clearly visible when the clasp is folded. When the clasp is entirely unfolded, the dial is turned downwards, which risks scratching the glass against the table&#39;s surface. Furthermore, the dial is read through a first glass closing the middle and a second glass connected to the frame; these two superimposed glasses make the reading poorly legible, increase the thickness of the watch and its cost. The length of the strap can be adjusted and take up several discrete positions defined by holes to engage the strap&#39;s pin; a finer, continuous adjustment is not possible.  
         [0007]     The present invention concerns an improvement to the watch cases including an unfolding clasp.  
         [0008]     The present invention aims in particular at improving the possibilities of personalized adjustment of the length of the flexible strap with a clasp.  
         [0009]     The present invention also aims at providing an alternative construction of watch case including a clasp.  
       BRIEF SUMMARY OF THE INVENTION  
       [0010]     The present invention thus proposes a watch case including an unfolding clasp for flexible strap that is advantageous thanks to the following features:  
         [0011]     a middle connected to a first end of the strap,  
         [0012]     a base comprising a first extremity connected in articulated fashion to the second end of the strap,  
         [0013]     an extension connected in articulated fashion to the middle and to the base,  
         [0014]     wherein the articulations are arranged in such a manner as to allow the middle, the extension and the base to superimpose in folded position, and the middle, the extension and the base to be juxtaposed in unfolded position,  
         [0015]     a cam or regulating element to hold by compression and/or friction the strap against the base, this element being able to be swung, displaced or pivoted to increase or reduce in a reversible manner the length of the folded position of the strap.  
         [0016]     The invention is based notably on the new observation that the watch cases combined with a clasp of known type do not allow the length of the strap to be adjusted in an entirely satisfactory fashion. The strap length regulating means are often not very convenient or require a strap shaped with a particular profile that is expensive to inject and impossible to make with certain material. Often, the length of the strap can only be adjusted by cutting the strap, which is irreversible, impossible to perform without additional tool and poorly suited to textile or leather straps for example whose extremity tends to unravel if they are cut. Other straps can only be adjusted with the aid of an additional tool necessary for removing a pin for example. Finally, watches with an unfolding clasp close to the middle and with a separate clasp, allowing the length to be adjusted, between the two extremities of the strap ends opposed to the middle are also known. These watches considerably reduce the advantages that may be expected from case-clasps.  
         [0017]     Following a preferred embodiment of the present invention, the strap is constituted of a single end having two extremities, having typically the shape of a band. It can be made of a material habitually used for watch straps, such as leather, textile or even, preferably, an extensible material, in particular an elastomer. According to this preferred embodiment, one of the two extremities of the strap is connected to the watch case whilst the second extremity is connected with the base.  
         [0018]     Advantageously, the previously mentioned regulating element comprises a locking element acting by locking or pressing on a selectable portion of the strap. It can thus be implemented with any type of strap, without requiring a particular profile for the strap. However, this does not exclude the presence of such a particular profile to reinforce the locking effect, such as a relief in the shape of grooves, according notably to the nature of the material used for the strap, advantageously in the case of an elastomer.  
         [0019]     The range of adjustment of the strap length is preferably great, for example on the order of the length of the watch case.  
         [0020]     The particular construction proposed thus constitutes an advantageous alternative to the prior art constructions.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     The present invention will be better understood with the aid of the attached figures which show:  
         [0022]      FIG. 1 , a perspective view of a watch case including an unfolding clasp in folded position.  
         [0023]      FIG. 2 , a perspective view of a watch case including an unfolding clasp in partially unfolded position.  
         [0024]      FIG. 3 , a perspective view of a watch case including an unfolding clasp in intermediary position.  
         [0025]      FIG. 4 , a partial enlarged perspective view of a watch case including an unfolding clasp in intermediary position, illustrating in particular the articulations and locking mechanism of the middle on the base.  
         [0026]      FIG. 5 , another partial enlarged perspective view of a watch case including an unfolding clasp in intermediary position, illustrating in particular the locking mechanism and the notch for the winding button.  
         [0027]      FIG. 6 , another partial enlarged perspective view of the base, illustrating the regulating element in open position.  
         [0028]      FIG. 7  corresponds to the view of  FIG. 6 , where the regulating element appears in closed position. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0029]     The inventive wristwatch includes a middle  1  in which a watch movement is lodged. A winding button  10  is connected to a winding shaft (not represented) and makes it possible to set the watch movement&#39;s time and/or regulate other functions.  
         [0030]     The strap  4  of the watch is constituted of a single end whose two extremities  40  and  41  are fastened to the watch case. The extremity  41  is thus fastened, for example by means of a spring pin or other means, to the upper side at 6 o&#39;clock of the middle  1 . The other extremity  40  is fastened at 12 o&#39;clock on a base  3  of clasp described further below. The strap is advantageously moulded or injected in a flexible and extensible material, for example in a material on the basis of silicone, in order to perfectly adapt to the wearer&#39;s wrist. A profiling  45  is preferably provided on the inside side of the strap to improve the skin&#39;s respiration and reduce sliding.  
         [0031]     The watch case further comprises a clasp extension  2 . One extremity of the extension is connected by a first hinge  20  ( FIG. 4 ) to the lower side of the middle, at 12 o&#39;clock, whilst the other extremity of the extension is articulated by means of a second hinge  21  with the clasp base  3  at 6 o&#39;clock. Following an advantageous embodiment, the pivoting articulation  20  is a hinge designed for being easily disassembled in order to easily isolate the middle from the other parts of the wristwatch. This is notably useful for performing different operations, notably for casing up the movement, the dial and the hands or for performing different tests, such as tightness tests, or even for making easier different repair interventions if necessary. To this effect, the hinge  20  includes a removable pin  22 , visible in  FIG. 4 .  
         [0032]     In the illustrated preferred embodiment, the extension is formed of a hollow metallic frame (stirrup), which notably allows the weight of the watch case to be reduced and the bottom of the middle  1  to be accommodated if this bottom is protruding. Preferably, as is clearly visible in particular in  FIG. 2 , the extension  2  has the shape of an open stirrup whose base is articulated with the base  3  through the intermediary of the hinge  21 . Thus, this particular shape of extension makes it easier to lodge the extremity  40  of the strap under the middle  1 . However, a clasp extension in the form of a full blade or formed itself of an elastic material can also be conceived within the frame of the invention. Furthermore, it is also possible in the frame of the invention to use clasp extensions in several elements to further increase the clasp&#39;s elongation when the clasp is opened or to improve the comfort of opening. Clasps integrated to the case of the butterfly type can thus be used.  
         [0033]     The base  3  is designed to come and rest against the wrist when the watch is worn. The bloc middle  1 —base  3  preferably forms a unit of monolithic aspect when the clasp is closed. To this effect, the base  3  and the middle fit one against the other without threshold at their junction.  
         [0034]     The base  3  includes a recess  30  sufficiently large and deep for lodging there the entire extension  2  is folded position. The extension  2  is thus dissimulated between the base and the middle when the watch is worn.  
         [0035]     As can be seen in particular in  FIG. 3 , the recess  30  also allows the extremity  40  of the strap  4  to be lodged. The depth with which the end  40  is engaged in the recess  30  can be adjusted to regulate the useful length of the strap according to the size of the wrist. In the illustrated embodiment, the strap  4  is held in the base  3  by a two-position eccentric cam  34  that can pivot parallel to the axis 3 o&#39;clock-9 o&#39;clock between a position where the strap is wedged between the cam  34  and the base  3  and an adjustment position (not illustrated) where the interstice between the cam  34  and the base  3  is sufficient to have the strap  4  slide. The strap is thus held by compression of an arbitrary portion of one of its upper or lower sides and/or by friction against the elements  3  and  34 . As previously mentioned, the strap is preferably of an elastic material, so that it takes up its form again when the pressure of the cam  34  is relaxed.  
         [0036]     The cam  34  can preferably be freed only when the clasp  1 ,  2 ,  3  is open; when the watch is closed, the case  1  blocks the cam&#39;s rotation, thus preventing an accidental maladjustment of the strap&#39;s length. The cam  34  is preferably arranged in such a manner as not to be disengaged by pivoting without a certain resistance, even when the clasp is open, so as to allow the clasp to open without risk of accidentally misadjusting the strap&#39;s length. The resistance to the pivoting of the cam  34  can be for example caused by an increased compression of the strap during rotation of the cam.  
         [0037]     In an embodiment not illustrated, the cam  34  can be released only by acting on an additional control organ, for example a push-button, or by lifting one of the portions of the strap. The cam  34  can also be constituted of several elements. The visible portion of the cam  34  preferably has the same shape and visual aspect as the extremity  400  of the strap connected to the other side of the case and thus engages between two horns  13  of the middle.  
         [0038]     Following a preferred embodiment, at least one banking  35  works with the cam  34  to prevent the latter from rotating around its axis. Preferably, the cam&#39;s rotation angle will be limited to a value lower than 90°. By way of example visible in  FIGS. 6 and 7 , at least one banking  35  is borne by the cam  34  and protrudes from at least one of its extremities. As can be seen in  FIG. 6 , when the cam  34  is in open position, the banking  35  coming into contact with the portion  37  of the horn  37  of the base, blocks the cam&#39;s rotation. In this position, the extremity  40  of the strap can freely slide under the cam. In the closed position of the cam  34 , represented in  FIG. 7 , the banking  35  comes into contact with the exterior edge  38  of the base  3  whilst the cam  34  immobilizes by compression the extremity  40  of the strap. It will be noted that the maximal opening of the rotation angle of the cam can be adjusted by using the banking&#39;s dimensions.  
         [0039]     The length of the recess  30  is preferably maximal, i.e. it is equal to the length of the base  3  minus the thickness of the recess&#39;s edge. The cam  34  is placed so as to rest as far as possible from the extremity of the recess closest to the articulation  21 . This particular arrangement allows the distance between the cam  34  and the bottom of the recess close to the hinge  21  to be increased and thus the range of adjustment of the strap&#39;s length to be maximized. The strap  4  is engaged under the extension  2  in the base  3 ; it is thus far from the bottom of the middle  1 , which can be prominent according to the thickness of the used movement. Thus, the bottom of the watch/movement will not disturb the engagement of the strap.  
         [0040]     Furthermore, the cam is arranged to exert a considerable pressure on the entire width of the strap. In this manner, the risk of the bracelet sliding outside the recess when only a small length of strap is engaged in the clasp can be minimized. By distributing the holding force of the cam  34  on the entire width of the strap, one furthermore reduces the local pressure and thus the risk of durably marking the surface of the strap. The resting surface of the base  3  on the lower side of the strap is preferably lower than the contact surface between the cam  34  and the upper side of the bracelet. This particular arrangement allows the strap to be held firmly thanks to the considerable pressure on the lower side whilst minimizing the risk of marking the strap&#39;s upper side.  
         [0041]     Holding the strap by friction and/or compression allows the inventive watch case to be used with any type of flexible strap, including leather or textile straps in which it would be difficult to provide fastening grooves or ribs. Banking means, for example bankings working on the case and on the strap or an ardillon engaged in a hole through the strap can however also be used.  
         [0042]     The extremity  40  of the strap  4  is connected to the base of the watch case. The traction of this extremity is thus exerted following a more or less straight comprised in the main plane of the base. Thus, the swinging torque on the case is minimal and the latter&#39;s lower side at 12 o&#39;clock does not risk lifting even if the bracelet is worn highly tensed. The extremity  41  of the strap connected to the case is preferably bent with a step  400  so that the traction force of this extremity is also exerted along a straight close to the wrist and more or less contained in the main plane of the base  3 . The lower side of the strap  4  is thus the closest to the wrist&#39;s skin on its entire length, which is more aesthetic, more comfortable and improves the watch&#39;s hold even during sudden movements.  
         [0043]     The watch case  1  comprises a mechanical locking device allowing the clasp to be locked in folded position. Said mechanical locking device can, as in the example represented in  FIG. 4 , comprise two push-buttons  11  and  12  capable of acting on elastically deformable elements. As can be seen in  FIG. 4 , the push-buttons  11  and  12  are placed on the two lateral sides of the middle  1 . It can be seen that the push-button  12  allows a mobile hook  120  connected to the middle  1  and working with a banking  33  on the base to be actuated ( FIG. 5 ). The push-button  12  can be pressed against the action of a spring or a blade, not represented, to disengage the hook  120  from the banking and thus open the clasp. A similar but symmetrical disposition is found on the other side of the case. The clasp can preferably be only opened by pressing simultaneously on the two push-buttons  11 ,  12  and then by lifting the middle  1  relatively to the base  3 . The mobile hook  120  advantageously comprises a beveled side  121 , visible in  FIG. 4 , allowing the clasp-case to be closed again and the hook  120  to be pushed in without having to press on the bush-button  12 . A symmetrical beveled side, not represented, is also found on the hook  11 .  
         [0044]     The arrangement of the push-buttons on the middle  1  rather than on the base  3  allows them to be moved away from the wrist and thus the risk of injury to the wearer to be reduced. The winding button  10  is accessible even when the clasp is folded, so that it is not necessary to open it to set the time. According to a preferred embodiment of the invention, the winding button  10  is placed at 9 o&#39;clock so that it cannot in any way come into contact with the back of the user&#39;s hand.  
         [0045]     A locking of the middle  1  on the extension  2  or of the base  3  on the extension, is also conceivable within the frame of the invention. The illustrated locking of thee base on the middle however has the advantage of holding the whole case  1 ,  2 ,  3  firmly in closed position.  
         [0046]     The base  3  comprises a semi-circular notch  32  placed opposite the winding button  10  in folded position. In the same manner, the push-buttons  11  and  12  preferably rest in notches  31  respectively  36  of the base. This particular arrangement allows the winding button and the push-buttons  11  and  12  to be placed close to the junction line between the base and the middle and thus to partially hide this line or at least to make it less visible.  
         [0047]     The watch case that is the object of the present invention will be particularly suited to persons doing certain sports, such as golf in particular.