Molded surface fastener, and molding method and molding apparatus of the same

Abstract

Molten resin material is continuously extruded from an extruding hole including a plurality of engaging-element-molding portions disposed with a constant pitch in a width direction of an extruding nozzle and a substrate-molding portion with which lower ends of the engaging-element-molding portions communicate. An ascending/descending member disposed at a front face of the extruding nozzle and made of a laterally long plank ascends and descends to vertically open and close the extruding hole of the extruding nozzle. As a result of such continuous molding, a surface fastener is continuously molded in which each of plurality engaging elements has stem and an engaging extruding head projecting at least toward one side from an end of the stem standing on a surface of a flat substrate. The engaging element thus molded has a thickness, in a direction perpendicular to a projecting direction of the engaging head, gradually increasing from a top portion of the engaging head to a base end of the stem. With such engaging elements that can be molded with a not conventional but new shape in various sizes, and its molding method and apparatus, maintenance and management are easy and productivity is high.

What is claimed:  
     
         1 . A molded surface fastener comprising a flat substrate and a large number of engaging elements integrally molded with the flat substrate, wherein each of the engaging elements has a stem standing on a surface of the flat substrate and an engaging head projecting from an end of the stem toward at least one side thereof, and a thickness of each of the engaging elements in a direction perpendicular to a projecting direction of the engaging head gradually increasing from a top of the engaging head to a base end of the stem.  
     
     
         2 . A molded surface fastener according to  claim 1 , wherein the engaging head projects in a direction perpendicular to a molding direction of the molded surface fastener.  
     
     
         3 . A molded surface fastener according to  claim 1 , wherein the flat substrate has a recessed groove which extends continuously in a direction perpendicular to a projecting direction of the engaging head between the engaging elements which are adjacent to each other in the projecting direction of the engaging head.  
     
     
         4 . A molded surface fastener according to  claim 1 , wherein the flat substrate has a recessed groove which extends continuously in a projecting direction of the engaging head between the engaging elements which are adjacent to each other in a direction perpendicular to the projecting direction of the engaging head.  
     
     
         5 . A molded surface fastener according to  claim 1 , wherein an end of the engaging head faces a surface of the flat substrate.  
     
     
         6 . A molded surface fastener according to  claim 1 , wherein a large number of the engaging elements are disposed in a large number of lines in a molding direction of the substrate, and the engaging elements adjacent across the lines are disposed in a staggered manner.  
     
     
         7 . A method for molding a surface fastener integrally molding a flat substrate and a large number of engaging elements by continuous molding, wherein said method comprises the steps of continuously extruding molten resin material from an extruding hole extending in a width direction of an extruding nozzle, and vertically opening and closing the extruding hole of the extruding nozzle by an ascending/descending member disposed in front of the extruding nozzle, in which the extruding hole comprises a plurality of engaging-element-molding portions disposed with a constant pitch in the width direction of the extruding nozzle and a substrate-molding portion with which lower ends of the engaging-element -molding portions communicate, the ascending/descending member is made of a laterally long plank, and at least a portion of the substrate-molding portion is open when the extruding hole is at a closed position.  
     
     
         8 . An apparatus for molding a surface fastener for integrally molding a flat substrate and a large number of engaging elements by continuous molding, wherein said apparatus comprises an extruding nozzle having an extruding hole extending in a width direction thereof, an ascending/descending member disposed in front of the extruding nozzle for vertically opening and closing the extruding hole, and a driving means for vertically moving the ascending/descending member, in which the extruding hole comprises a plurality of engaging-element-molding portions disposed with a constant pitch in the width direction of the extrusion nozzle and a substrate-molding portion with which lower ends of the engaging-element-molding portions communicate, the ascending/descending member is made of a laterally long plank, and at least a portion of the substrate-molding portion is open when the extruding hole is at a closed position.  
     
     
         9 . An apparatus for molding a surface fastener according to  claim 8 , wherein the driving means has a crank mechanism connected through a link.  
     
     
         10 . An apparatus for molding a surface fastener according to  claim 8 , wherein the driving means has a cam mounted to a rotating shaft and a cam contact which abuts on the cam.  
     
     
         11 . An apparatus for molding a surface fastener according to  claim 8 , wherein the extruding nozzle has first and second extruding holes disposed symmetrically and independently on upper and lower portions of the extruding nozzle.  
     
     
         12 . An apparatus for molding a surface fastener according to  claim 8 , wherein the ascending/descending member comprises first and second pectinate planks having opening portions formed in a longitudinal direction thereof so as to correspond to the engaging-element-molding portions such that the opening portions do not overlap each other, and the first and second ascending/descending members are disposed in front and in rear to face the extruding hole and to alternately ascend and descend by the driving means.  
     
     
         13 . An apparatus for molding a surface fastener according to  claim 12 , wherein the first ascending/descending member is made of a flat plate, a non-opening portion of the second ascending/descending member is in such a shape that the non-opening portion fits into the opening portion of the first ascending/descending member, and a vertical length of the opening portion of the first ascending/descending member is equal to or larger than a sum of a length of the non-opening portion of the second ascending/descending member and an ascending/descending amount of the non-opening portion.  
     
     
         14 . An apparatus for molding a surface fastener according to  claim 12 , wherein the adjacent engaging-element-molding portions of the extruding hole are alternately disposed in front and in rear, the opening portion of the first ascending/descending members slidably fit on the engaging-element-molding portion that is projecting forward, and a non-opening portion of the second ascending/descending member is slidably in contact with a front face of the forward-projecting engaging-element-molding portion.