Fastener element and slide fastener

Abstract

A fastener element includes: an engagement portion; and a first extension and a second extension that extend from the engagement portion, in which each of the first extension and the second extension includes: a holding portion that holds a side edge of a fastener tape between the holding portion of the first extension and the holding portion of the second extension; and a thin portion disposed closer to the engagement portion than the holding portion in an extending direction of the first extension or the second extension, each of the first extension and the second extension has a thickness in a direction orthogonal to the corresponding extending direction and a longitudinal direction of the fastener tape, and in each of the first extension and the second extension, a minimum dimension of the thickness of the thin portion is smaller than a maximum dimension of the thickness of the holding portion.

What is claimed is: 
     
         1 . A fastener element to be attached to a fastener tape, the fastener element being made of metal, the fastener element comprising: 
 an engagement portion; and   a first extension and a second extension, the first extension and the second extension extending from the engagement portion, the first extension being disposed opposing the second extension, wherein   each of the first extension and the second extension includes: a holding portion configured to hold a side edge of the fastener tape, the side edge of the fastener tape being held between the holding portion of the first extension and the holding portion of the second extension; and a thin portion disposed closer to the engagement portion than the holding portion in an extending direction of the first extension or the second extension,   each of the first extension and the second extension has a thickness in a direction orthogonal to the corresponding extending direction and a longitudinal direction of the fastener tape, and   in each of the first extension and the second extension, a minimum dimension of the thickness of the thin portion is smaller than a maximum dimension of the thickness of the holding portion.   
     
     
         2 . The fastener element according to  claim 1 , wherein in a projection view of the fastener element along the longitudinal direction, the minimum dimension of the thickness of the thin portion is smaller than a minimum dimension of the thickness of the holding portion in each of the first extension and the second extension. 
     
     
         3 . The fastener element according to  claim 1 , wherein  
       each of the first extension and the second extension further includes a groove of which bottom is the thin portion, and 
       the groove of the first extension and the groove of the second extension are opened facing each other to form a groove space therebetween. 
     
     
         4 . The fastener element according to  claim 3 , wherein a bottom surface of the groove of each of the first extension and the second extension has a concave arc shape when viewed in the longitudinal direction. 
     
     
         5 . The fastener element according to  claim 3 , wherein the engagement portion includes: a first head connected to the first extension; a second head connected to the second extension; a connecting portion connecting the first head to the second head; and a head groove provided between the first head and the second head and opened on a side opposite to the groove space. 
     
     
         6 . The fastener element according to  claim 5 , wherein the connecting portion has a curved surface extending continuously to inner surfaces of the grooves of the first extension and the second extension and curving to be convex toward the groove space when viewed in the longitudinal direction. 
     
     
         7 . The fastener element according to  claim 5 , wherein  
       the first head has a tapered shape with a dimension in the longitudinal direction decreasing toward a side opposite to the first extension, and 
       the second head has a bulging shape bulging on opposite sides of the first head in the longitudinal direction. 
     
     
         8 . The fastener element according to  claim 7 , wherein the second head includes: a groove side surface that forms a part of an inner surface of the head groove; and a pair of locking surfaces, the locking surfaces being disposed closer to the first head than the groove side surface on opposite sides of the connecting portion in the longitudinal direction. 
     
     
         9 . The fastener element according to  claim 7 , wherein the thin portion of the first extension partially forms shoulders as a pair that are positioned on opposite sides of the second extension in the longitudinal direction, when viewed in a direction in which the first extension and the second extension face each other. 
     
     
         10 . The fastener element according to  claim 9 , wherein the minimum dimension of the thickness of the thin portion of the first extension is larger than the minimum dimension of the thickness of the thin portion of the second extension. 
     
     
         11 . The fastener element according to  claim 1 , wherein  
       each of the first extension and the second extension includes an outer surface disposed on a side opposite to an opening of the fastener element between the first extension and the second extension, and 
       the outer surface of each of the first extension and the second extension is provided with a protrusion, a pattern shape of the protrusion of the first extension being different from a pattern shape of the protrusion of the second extension. 
     
     
         12 . A slide fastener comprising the fastener element according to  claim 1 .