Slide Fastener

Abstract

There is provided a slide fastener including a fastener chain and a slider. The slider includes upper and lower blades, a front end wall having a first front mouth and a second front mouth provided below the first front mouth, and one rear mouth. The slider is movable in a first direction to engage a pair of element rows, and in a second direction to disengage the pair of element rows. Each element has a base portion fixed to respective fastener tapes and a head portion configured to be engaged with the opposing elements. The head portion has a first head portion arranged at a side of upper surfaces of the tapes and a second head portion arranged at a side of lower surfaces of the tapes. The first head portion is formed to be offset from the second head portion in the first direction.

1 . A slide fastener, comprising:
 a fastener chain comprising a pair of fastener stringers having a pair of fastener tapes respectively having upper surfaces and lower surfaces opposite to the upper surfaces and element rows respectively constituted of a plurality of elements fixed to respective edge portions of the pair of fastener tapes at a predetermined pitch, the fastener chain in which the element rows are arranged so as to oppose each other; and   a slider including an upper blade arranged at a side of the upper surfaces, a lower blade arranged at a side of the lower surfaces, a front end wall connecting the upper blade with the lower blade and having a first front mouth for allowing the first element row to enter and exit therethrough and a second front mouth provided at the side of the lower surfaces relative to the first front mouth, for allowing the second element row to enter and exit therethrough, and one rear mouth for allowing the pair of element rows in an engaged state to enter and exit therethrough,   wherein the slider is movable in a first direction, along which the slider is moved to engage the element rows with each other, and in a second direction opposite to the first direction, along which the slider is moved to disengage the element rows from each other,   wherein each of the elements has a base portion fixed to the respective fastener tapes and a head portion protruding from the base portion and configured to be engaged with the opposing elements;   wherein the head portion of each of the elements has a first head portion arranged at the side of the upper surfaces and a second head portion arranged at the side of the lower surfaces of the fastener tapes,   wherein the first head portion is formed to be offset from the second head portion in the first direction.   
     
     
         2 . The slide fastener according to  claim 1 ,
 wherein each of the elements has a neck portion located between the base portion and the head portion and having a width smaller than those of the base portion and the head portion,   wherein the neck portion of each of the elements has a first neck portion arranged at the side of the upper surfaces and a second neck portion arranged at the side of the lower surfaces of the fastener tapes,   wherein the first neck portion is formed to be offset from the second neck portion in the first direction.   
     
     
         3 . The slide fastener according to  claim 2 ,
 wherein each of the elements comprises:
 a first protrusion portion formed on the first head portion at a side of the first direction; 
 a first recess portion formed on the first neck portion at a side of the first direction; 
 a second protrusion portion formed on the second head portion at a side of the second direction; and 
 a second recess portion formed on the second neck portion at a side of the second direction, 
   wherein upon engaging of the pair of fastener stringers, the first protrusion portion of the elements located at one side is engaged with the second recess portion of the opposing elements, and   wherein the first recess portion of the elements located at the one side is engaged with the second protrusion portion of the opposing elements.   
     
     
         4 . The slide fastener according to  claim 1 ,
 wherein an offset amount of the first head portion from the second head portion is 0.2 mm or greater and 0.3 mm or smaller, and   wherein a ratio of the offset amount with respect to a dimension of the head portion of the elements along the first direction is 9% or greater and 15% or smaller.