Patent Publication Number: US-11019889-B2

Title: Removable bracelet for a watch or equivalent and device for attaching the same

Description:
This application claims priority from European Patent Application No. 17199712.5 filed on Nov. 2, 2017; the entire disclosure of which is incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to the field of removable bracelets or straps which allow an object, such as a watch, to be secured to the wrist. 
     BACKGROUND OF THE INVENTION 
     Bracelets and especially watch bracelets are connecting elements made of different types of materials—leather, plastic, metal, sometimes even fabric—which allow an object such as a watch, but also more generally a piece of jewellery of any shape, to be secured to the wrist of the person who wishes to wear it. These bracelets are fitted to the person&#39;s wrist and are usually directly attached to the watch case horns by means of small metal rods called bars which are fixed inside a suitable housing provided in the horns. 
     In the case of damage or simply for aesthetic reasons, the user may have to change the bracelet several times over the life of his watch. To this end, there are attachment devices which make it possible to change bracelets more or less easily without the use of specific tools. However, although no specific tools are required to change the bracelet and this can therefore be done by the user, it may be difficult to handle the attachment device, and/or the device may have control members that are not only visible from outside the bracelet but are also liable to catch or snag. Thus, for example, European Patent No EP2766587 discloses an attachment device that has these drawbacks. The device includes two spring lugs, one of which is provided with a finger projecting outside the bracelet, the movement of the finger causing the lug to retract into the bar. 
     SUMMARY OF THE INVENTION 
     To overcome the aforecited drawbacks, it is a main object of the invention to propose a new attachment device which is easy for the user to handle and which can be arranged invisibly inside the bracelet. It is also an object of the present invention to propose an attachment device which is robust, as attachment bars are generally relatively fragile. 
     To this end, the present invention proposes an attachment device provided with a control member intended, after insertion inside the bracelet, to move vertically with respect to the bracelet. In this configuration, the attachment device and more particularly the control member, can be entirely embedded in the bracelet and operated by using the flexibility of the material that covers the control member. 
     The control member also has the feature of being offset with respect to the sliding axis of two pins which form the attachment bar, which increases robustness and guiding precision compared to a configuration wherein the control member is positioned on the sliding axis of the pins. 
     As the control member is offset with respect to the sliding axis of the pins, the attachment device is provided with connecting elements between the control member and the attachment bar which transform the vertical movement of translation of the control member into a lateral sliding motion of the bar between a position of engagement and a retracted position wherein the bar is detached from the object to which it is fixed. 
     Advantageously, the connecting elements comprise two arms articulated about an arbor arranged at a proximal end of said arms, the two pins being respectively connected to the distal end of the articulated arms via connecting rods. The control member and the articulated arms are configured to produce a movement apart of the arms around the arbor resulting in the moving together of their distal ends, which are connected to the two pins, thereby placing said pins in a retracted position. 
     In other words, the connecting elements successively comprise between the control member and the pins:
         two arms articulated at one end about a vertical arbor, called the pivot arbor, the arms being arranged around the control member symmetrically with respect to a line connecting said pivot arbor and the translation arbor of the control member,   two connecting rods each pivoting on the other end of said arms and respectively integral with the pins.       

     In use, the pivoting of the arms following actuation of the control member causes a lateral movement of the connecting rods and thereby a movement of the pins. 
     Other advantages will appear from the features set out in the claims, and from the detailed description of the invention illustrated hereinafter with reference to the annexed drawings, provided as non-limiting examples. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  represents a plan view of the attachment device according to the invention in a position of engagement. 
         FIG. 2  is a cross-section along axis AA of  FIG. 1 . 
         FIG. 3  is a cross-section along axis BB of  FIG. 1 . 
         FIG. 4  represents the device of  FIG. 1  in a retracted position. 
         FIG. 5  is a perspective view of the attachment device according to the invention in a position of engagement. 
         FIG. 6  is a perspective view of a bracelet and of the corresponding watch case with the attachment device according to the invention seen transparently through the bracelet. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The attachment device  10  according to the invention represented in  FIGS. 1 to 5  is intended to be invisibly arranged at the end of a bracelet, such as a watch or jewellery bracelet. It is more particularly illustrated in  FIG. 6  in the context of attachment of a bracelet  100  to a watch case  200  provided with horns  21 ,  22 , comprising blind or through holes  23 ,  24  for housing the bar of the attachment device. Conversely, in another embodiment of the invention, it is possible to envisage a lug with pivots in which case the bar will have holes at its ends for receiving the pivots. 
     Attachment device  10  according to the invention can adopt two positions represented in  FIGS. 1 and 4  consisting respectively of a rest position, which can also be described as the position of engagement, corresponding to a position in which the bracelet is attached to the watch case, and a retracted position in which the bracelet is detached from the watch case. 
     Attachment device  10  according to the invention includes a support plate  14  on which is mounted the mechanism for switching from one position to the other. This plate  14  is formed of a base  14   a  surmounted by several arbors  11 ,  17  on which the elements of the mechanism are movably mounted ( FIG. 2 ). Plate  14  is thus provided with an arbor  17  perpendicular to the plane of base  14   a  on which is mounted to move in translation a control member, namely a push button  1 , which makes it possible to actuate the mechanism and more precisely to move in translation two pins  4 ′,  4 ″, serving as a retractable bar. 
     These two pins  4 ′,  4 ″ are arranged on the same axis on which they slide in translation ( FIG. 1 ). They are connected by a spring  2  holding pins  4 ′,  4 ″ in the rest position in the absence of contact on the push button by a user. The translation of pins  4 ′,  4 ′ along their axis is ensured by guide walls  3  integral with support plate  14  and arranged along the axis on either side of each pin  4 ′  4 ″, and spring  2  with, in the illustrated example, three pairs of walls  3  respectively arranged at the ends and at the centre of the plate along said axis. 
     According to the invention, push button  1  is not arranged on the axis of the pins but offset with respect to said axis. Hence, the movement of the two pins  4 ′,  4 ″, is linked to the movement of push button  1  by means of two arms  5 ′,  5 ″ respectively articulated on connecting rods  6 ′,  6 ″ which are in turn secured to pins  4 ′,  4 ″ by means of fingers  15 ′,  15 ″ protruding onto each pin  4 ′,  4 ″. 
     The two arms  5 ′,  5 ″ are mounted to pivot on a vertical arbor  11  formed in support plate  14  and visible, among others, in  FIGS. 1 and 2 . Arms  5 ′,  5 ″ are arranged symmetrically with respect to the line formed by arbors  11  and  17  aligned in a direction perpendicular to the axis of pins  4 ′,  4 ″. Arms  5 ′,  5 ″ overlap on arbor  11  with respectively one arm  5 ″ in a lower position and one arm  5 ′ in an upper position with respect to the plane of the support plate. They respectively pass around control member  1  before crossing each other at a point  12 , which is also aligned on the line formed by arbors  11  and  17  and diametrically opposite to arbor  11 . As detailed in  FIG. 5 , each arm  5 ′,  5 ″ includes a first curved portion, referenced a, which substantially follows the shape of push button  1 , and extends substantially between arbor  11  and crossing point  12 . This first curved portion a is followed by a second rectilinear portion, referenced b, extending substantially from crossing point  12  up to pins  9 ′,  9 ″ ensuring the rotational connection between arms  5 ′,  5 ″ and connecting rods  6 ′,  6 ″. In the illustrated example, the arm  5 ″ in the lower position passes around to the right of push button  1  and then extends to the left to control the movement of the corresponding pin  4 ″. Through symmetry, arm  5 ′ in the upper position passes around to the left of push button  1  and extends to the right to control the movement of the corresponding pin  4 ′. In the illustrated example, on the inner sides of their curved portion, the arms have an inclined wall on which the lateral sides of the tapered push button are intended to slide ( FIG. 3 ). Alternatively, the inclined wall could be replaced by a rounded surface to reduce the friction surface. Further, each arm  5 ′,  5 ″ includes an extra thickness, referenced c and visible in  FIG. 5 , which is arranged on its curved portion a and takes up the difference in height in areas where the arms are not superposed and hence ensures a symmetrical movement of the two arms when the push button is actuated. More precisely, the arm  5 ″ in the upper position on arbor  11  includes an extra thickness  5 ″ c  arranged in the opposite direction to support plate  14  whereas arm  5 ′ in the upper position includes an extra thickness  5 ′ c  extending in the direction of support plate  14 . These extra thicknesses are arranged so as not to hinder the movement of the arms during pivoting. 
     Arms  5 ′,  5 ″ are attached to connecting rods  6 ′,  6 ″ via pegs  9 ′,  9 ″ allowing a relative rotational movement between arms  5 ′,  5 ″ and connecting rods  6 ′,  6 ″. To this end, pegs  9 ′,  9 ″ slide inside holes  18 ′,  18 ″ arranged in support plate  14  in arcs centred on arbor  11 . 
     Connecting rods  6 ′,  6 ″ are flat parts, of oblong shape in the illustrated example, and of substantially equal thickness to that of the arms. A hole  16 ′,  16 ″, also of oblong shape, is provided in each connecting rod  6 ′,  6 ″. Finger  15 ′,  15 ″, secured to pins  4 ′,  4 ″, is guided in this hole. During their movement, connecting rods  6 ′,  6 ″ are maintained perpendicular to the axis of pins  4 ′,  4 ″ by means of rigid walls  13 ′,  13 ″ provided in pins  4 ′,  4 ″ and between which connecting rods  6 ′,  6 ″ slide. 
     As shown in  FIG. 1 , pins  4 ′,  4 ″ and connecting rods  6 ′,  6 ″ are arranged differently depending on the position of the arm  5 ′,  5 ″ to which they are connected. For arm  5 ″ in the lower position, connecting rod  6 ″ is positioned above the arm. More precisely, arm  5 ″ is positioned between hole  18 ″ and connecting rod  6 ″ with finger  15 ″ of pin  4 ″ turned to the side opposite to plate  14 . Conversely, for arm  5 ′ in the upper position, connecting rod  6 ′ is positioned underneath the arm, i.e. between hole  18 ′ and arm  5 ′ with finger  15 ′ of pin  4 ′ turned towards support plate  14 . 
     As detailed in the example embodiment illustrated in  FIG. 5 , each pin  4 ′,  4 ″ includes a cylindrical end  4 ′ a ,  4 ″ a  intended to be housed inside holes provided in the watch case horns. After the cylindrical portion, pin  4 ′,  4 ″ includes a tapered portion  4 ′ b ,  4 ″ b  flaring towards a U-shaped portion  4 ′ c ,  4 ″ c  inside which slides the corresponding connecting rod  6 ′,  6 ″ with the U-shaped walls  13 ′,  13 ″ of the U performing the function of guiding the connecting rod. This portion includes finger  15 ′,  15 ″ standing in the hollowed portion of the U. After the U-shaped portion, pin  4 ′,  4 ″ includes a second cylindrical portion  4 ′ d ,  4 ″ d  around which spring  2  is wound. The diameter of this portion is smaller than the height of wall  13 ,  13 ″, so that the latter forms a shoulder on which spring  2  rests. It is evident that other geometries of pins  4 ′,  4 ″ could be envisaged provided that they comprise an end portion able to cooperate with the holes in the bars arranged in the lugs of a watch case. In a variant, pins  4 ′,  4 ″ could even made in one piece comprising a median portion forming a spring. 
     Ideally, the pins are made of metal with an anti-friction coating at the ends intended to be housed inside the watch case to prevent scratches inside the horns. This coating may be made, in particular, of PTFE or polyurethane charged with a perfluopolyether (PFPE) oil. 
     As regards push button  1 , this has a circular bearing surface mounted on a tapered base with a recess at its centre for the passage of arbor  17 . The contact surfaces between push-button  1  and arms  5 ′,  5 ″ are arranged to slide easily one over the other. It may be useful to improve sliding through a suitable choice of materials, by using either an intrinsically slippery material such as a fluorinated polymer, or a coating of such a polymer. Again, to facilitate the sliding of the push button, the latter has a conical shape with a wall inclined at an angle preferably comprised between 30 and 60°, more preferably between 40 and 50°, with respect to arbor  17 . The slope of the push button is chosen such that the travel of the button is comprised between 0.3 and 0.8 mm. 
     Advantageously, the push button can be mounted on elastic means such as a spring or a strip (not represented) which assist, together with spring  2  positioned between the pins, in returning the push button to the high position when the latter is released. These elastic means can be used as an audible foolproof device. To this end, the elastic means may include a flexible metal strip which stretches when the control member is pressed and relaxes when it goes beyond a certain travel, the relaxing of the strip producing a distinctive click which has the further advantage of indicating to the user that the pins, and hence the bracelet, are properly attached to the watch case. 
     The operation of the device is illustrated by means of  FIGS. 1 and 4 . When button  1  is pressed ( FIG. 4 ), the inclined lateral surfaces of button  1  press on the corresponding surfaces of arms  5 ′,  5 ″. As this happens, arms  5 ′  5 ″ move apart between arbor  11  and crossing point  12 . This movement apart causes a movement of pegs  9 ′,  9 ″ at the end of arms  5 ′,  5 ″ in guide holes  18 ′,  18 ″. This rotational movement causes a lateral and vertical movement of translation of connecting rods  6 ′,  6 ″. The vertical translational movement of connecting rods  6 ′,  6 ″ is taken up by the sliding of said rods between walls  13 ′,  13 ″ and by the sliding of finger  15 ′,  15 ″ in the corresponding hole  16 ′,  16 ″. However, the lateral movement of connecting rods  6 ′,  6 ″ causes a corresponding movement of pins  4 ′,  4 ″ and, consequently, the retraction of pins  4 ′,  4 ″. When the pressure on button  1  is released, spring  2  pushes pins  4 ′,  4 ″ back into the rest position, pushing back arms  5 ′,  5 ″ which in turn push button  1  back into the rest position, possibly aided by the aforementioned additional elastic means. 
     According to the invention, support plate  14  surmounted by the mechanism is invisibly arranged inside the bracelet. The attachment device can thus be placed inside a leather, woven or embroidered textile or plastic bracelet with a marker showing the user where to press on the button. It is also possible to envisage placing the attachment device according to the invention on a metal or ceramic bracelet in a plastic portion overmoulded onto a bracelet link. In each case, it is the flexibility of the bracelet material that makes it possible to actuate the push button embedded in the bracelet. Preferably, the bearing surface of the control member is positioned between 0.2 and 0.7 mm under the surface of the bracelet. It can be placed under the lower side of the bracelet, i.e. the side intended to be placed facing the wrist, or conversely under the external face of the bracelet. 
     Finally, it will be specified that support plate  14  provided with the mechanism can be confined inside a case pierced with an opening for the passage of a push button. To this end, the plate can be delimited at certain places by rims  17  whose height is substantially equal to that of the superposed arms, with a closing lid (not represented) resting on said rims.