Clasp

Abstract

The invention relates to a lever structure of clasps such as spring ring clasps or lobster claw clasps. The clasp includes a substantially annular clasp body cut at one end to have a cut-away portion, an open/close member inserted inside the clasp body such as to slide in directions to open and close the cut-away portion, and a lever integrally formed with the open/close member such as to protrude outwards from the clasp body. The lever includes a neck portion that passes through a slit of the clasp body, and a lever body with a grip surface provided to a distal end of the neck portion such as to extend in a direction orthogonal to open/close sliding directions of the open/close member. The grip surface has a width that is set longer than a cross-section diameter of the clasp body.

1 . A clasp comprising:
 a substantially annular clasp body cut at one end to have a cut-away portion;   an open/close member inserted inside the clasp body such as to slide in directions to open and close said cut-away portion; and   a lever integrally formed with the open/close member such as to protrude outwards from the clasp body, wherein the lever includes a neck portion that passes through a slit of the clasp body, and a lever body with a grip surface provided to a distal end of the neck portion such as to extend in a direction orthogonal to open/close sliding directions of the open/close member, the grip surface having a width that is set longer than a cross-section diameter of the clasp body.   
   
   
       2 . A clasp according to  claim 1 , wherein the open/close member and a lever forming piece are integrally formed from a flat metal plate by punching;
 the lever forming piece is made up of a neck portion forming piece protruding substantially from a center of said open/close member and a lever body forming piece integrally formed to an upper part of the neck portion forming piece; and   the neck portion and the lever body are formed by turning the neck portion forming piece with the lever body forming piece substantially 90° around said neck portion forming piece as an axis relative to the open/close member.   
   
   
       3 . A clasp according to  claim 1 , wherein the open/close member and a lever forming part are made of a single wire;
 the open/close member is made up of a pair of front and back open/close member forming parts that are formed by bending both ends of the wire in a circular arc shape having the same radius of curvature;   said lever forming part is made up of a pair of neck portion forming parts standing up substantially vertically and extending linearly between said pair of open/close member forming parts in close contact with each other, and a lever body forming part bridging across the neck portion forming parts at an upper end of the neck portion forming parts extending annularly from one to the other of the neck portion forming parts; and   the neck portion and the lever body are formed by turning said pair of neck portion forming parts with the lever body forming part substantially 90° around the pair of neck portion forming parts as an axis relative to the open/close member.   
   
   
       4 . A clasp according to any one of  claims 1  to  3 , wherein the clasp comprises:
 the cut-away portion formed by cutting one end of a hollow ring to provide an entrance;   a slotted hole slit extending from near one end of the cut-away portion along the hollow ring a distance corresponding to a stroke length of the lever;   a fixed grip fixed to an outer circumference of said hollow ring and having a hole in a center thereof;   a stopper provided in a tubular interior of the hollow ring slightly away from the other end of said cut-away portion; and   a spring inserted in the tubular interior of the hollow ring such as to be interposed between the stopper and the open/close member to bias the open/close member in a locking direction.   
   
   
       5 . A clasp according to  claim 4 , wherein a grip
 surface formed by the fixed grip and the grip surface of the lever body are arranged opposite each other.   
   
   
       6 . A clasp according to  claim 1 , wherein the clasp comprises:
 a hollow base part with an open front and back to form a slit;   a circular-arc shaped frame extending integrally from one end of the base part and provided with the cut-away portion so that there is a gap between the frame and the other end of the base part; and   the open/close member inserted inside said base part and pivotally supported in a middle portion thereof to said base part, one end of the open/close member protruding from said base part to openably close said cut-away portion and to be able to engage with a distal end of said frame, the other end of said open/close member being formed with the neck portion and the grip surface that protrude outwards from the slit of said base part.