Device for the fine adjustment of the useful length of a wrist strap, such as the wrist strap of a watch

Abstract

This adjustment device comprises: a first adjustment member with a fixed position relative to the longitudinal axis of the strap; first guide means connected to this first adjust member; a connecting member engaged on the one hand with said first guide means and on the other hand with the other of the strap halves; second guide means for rotational guidance, connected to said first adjustment member; a second or manual adjustment member having guide means shaped to engage with said second guide means of the first adjustment member; and means for transmitting movement between said second or manual adjustment member and said connecting member to turn the circular movement of the second or manual adjustment member into a rectilinear movement of said connecting member.

1 . A device for the fine adjustment of the useful length of a wrist strap, such as the wrist strap of a watch, comprising two portions and a clasp for connecting the free ends of said portions to allow said free ends to be connected at a specific useful length, characterized in that it comprises a first adjustment member, attaching means for connecting said first adjustment member to one of the portions of the wrist strap at a fixed position relative to the longitudinal axis of the wrist strap, first guide means extending in the longitudinal direction of the wrist strap, integral with said first adjustment member, a connecting member in engagement on the one hand with said first guide means and on the other hand with the other of the portions of the wrist strap, second means for guiding in rotation, integral with said first adjustment member, a second manual adjustment member having guide means shaped to be brought into engagement with said second means for guiding the first adjustment member in rotation and means for transmitting movement between said second manual adjustment member and said connecting member so that the circular movement of the second manual adjustment member is transformed by said first guide means into a rectilinear movement of said connecting member. 
   
   
       2 . The adjustment device as claimed in  claim 1 , in which said attaching means for connecting said first adjustment member to one of the portions of the wrist strap at a fixed position relative to the longitudinal axis of the wrist strap comprise two arms articulated to one another, provided with means for hooking to one another, forming a clasp with a folding buckle, the free end of one of said arms being integral with one of the portions of the wrist strap and the free end of the other of said arms comprising said attaching means of said first adjustment member. 
   
   
       3 . The device as claimed in  claim 1 , in which said means for transmitting movement between said second manual adjustment member and said connecting member comprise a semi-circular drive element in engagement with said connecting member and of which one end is coaxial with the axis of rotation of said second manual adjustment member. 
   
   
       4 . The device as claimed in  claim 1 , in which said means for transmitting movement between said second manual adjustment member and said connecting member comprise a connecting rod of which one end is articulated to said connecting member and the other end is articulated to said second manual adjustment member around an axis which is offset relative to the pivot axis defined by said guide means in engagement with said second means for guiding said first adjustment member in rotation. 
   
   
       5 . The device as claimed in  claim 1 , in which said means for transmitting movement between said second manual adjusting member and said connecting member comprise a toothed sector which is coaxial and integral with said second manual adjustment member, a radially oriented rack integral with said connecting member and a pinion in engagement with said toothed sector and with said rack. 
   
   
       6 . The device as claimed in  claim 1 , in which a spring element is arranged between the first and second adjustment members to create friction therebetween. 
   
   
       7 . The device as claimed in  claim 3 , in which said semi-circular drive element is an opening made through said second adjustment member, said spring element being formed by a disc housed in a circular opening centered on the center of said semi-circular opening and in engagement with said connecting member. 
   
   
       8 . The device as claimed in  claim 1 , in which said means for transmitting movement between said second manual adjustment member and said connecting member comprise two semi-circular elements of which the ends of the active parts are located on the same diameter of said second means for guiding the first adjustment member in rotation and in which said connecting member is integral with a slide in engagement with a diametrical slideway, integral with the first adjustment member, said slide having two projections to be brought into alternate and successive engagement, with each half turn of the second manual adjustment member, with the two semi-circular elements of said means for transmitting movement. 
   
   
       9 . The device as claimed in  claim 8 , in which said second manual adjustment member has a central opening to receive a fixed indicator member provided with a diametrical slideway in engagement with the slide. 
   
   
       10 . The device as claimed in  claim 8 , in which said second manual adjustment member has angular positioning means distributed about its rotational axis, a resilient positioning member being mounted on the first adjustment member to be brought successively into engagement with said angular positioning means.