Fasteners for jewelry and the like
This is a division of application Ser. No. 349,758 filed Feb. 18, 1982. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to fasteners for jewellery and the like. 
     Articles of jewellery, silver ware, trinketry ware and the like require fasteners that can be operated with a minimum of manual intervention and which are composed of a limited number of components. Previously proposed fasteners tend to be relatively complex, not very practical or reliable, and of poor aesthetic quality. 
     SUMMARY OF THE INVENTION 
     According to the invention there is provided a fastener for jewellery and the like, comprising a foil bent to form a box-like structure, the structure including a hook defining a seat for a removable fastening element, and a resiliently mounted tongue biased against the interior of the hook to close the seat. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which: 
     FIGS. 1 and 2 are perspective views showing, respectively, a fastener on its own, and when fitted to a chain; 
     FIGS. 3 and 4 are longitudinal sections showing the fastener in its closed and opened conditions respectively; 
     FIG. 5 is a section taken on line V--V of FIG. 3; 
     FIG. 6 shows a foil blank from which the fastener is formed; 
     FIG. 7 is a perspective view of a modified embodiment of the fastener; and 
     FIG. 8 is a section similar to FIG. 5 of another embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The fastener is formed from a metal foil blank 1 (FIG. 6) having a portion 3 defining the base of the fastener, from the sides of which two symmetrical lugs 5 extend to be bent upwardly. The rear edges 5A of the lugs 5 are approximately at right angles to the base 3, and the front edges 5B are inclined to facilitate the introduction and withdrawal of a bracket or other removable annular fastening element 7 of a chain C. A front extension 9 of the base 3 is so curved as to make up a half-open hook. A longer rear extension 10 is curved at 10A and defines together with the edges 5A a seat for receiving--in an articulated manner--a bracket or other fixed annular fastening element 13 of the chain C. The extension 10 forms a resilient tongue which lies between the two lugs 5 and extends into the cavity of the hook 9. 
     Preferably, the tongue 10 curves slightly outwardly with respect to the lugs 5 to provide beneficial external stresses, and then curves inwardly near its free end portion so as to enter the cavity of the hook 9. Owing to the elasticity of the metal, the tongue 10 is kept in contact with the inside of the free end of the hook 9 to define in this way a closed transverse cavity for the removable fastening element 7. In order to open this cavity, the tongue must be pressed toward the base 3 in the direction of arrow f1. The sloping edges 5B facilitate the pressure on the tongue as well as the introduction and withdrawal of the removable fastening. 
     As can be seen from FIGS. 3 and 4, the fastening element 7 has a diameter which is almost as large as the distance between the tongue 10 and a bottom surface of the hook 9 which faces an upper surface of the base 3, when the tongue is fully depressed against the top surface of the base. In this way, as shown in FIG. 3, a secure engagement is obtained between the fastening element 7 and the hook 9. 
     The blank 1 when bent as described above makes a box-shaped structure. 
     To facilitate the action on the tongue 10, there may be provided a buckled rib 15 projecting from the center of the tongue (FIG. 7) and which is able to make the downward thrust of the tongue 10 easier. 
     FIG. 8 shows an embodiment where the base 3 and fins 5 are so shaped as to form a shell 17 having a substantially continuous curvature. 
     The tongue 10 may be made stiff by a transverse curvature, as can be seen in FIG. 8. 
     To ensure the elasticity of the tongue, a spring may be arranged between the base 3 and the tongue. This spring may be an elastic foil 19 located in the inside of part 10A and the adjacent zones of base 3 and tongue 10. The elastic foil may be coupled to the blank 1.