Slide fastener

Claim 1

A FLEXIBLE CLOSURE COMPRISING IN COMBINATION, OPPOSED FLEXIBLE CLOSURE STRIPS IN FACING RELATIONSHIP HAVING ADJACENT PARALLEL WEB PORTIONS EXTENDING DOWNWARDLY AT THE LOWER EDGE OF THE STRIPS, AND HAVING MARGINAL PORTIONS GENERALLY ABOVE THE WEB PORTIONS WITH RELEASABLY INTERLOCKING CONTINUOUS RIB AND GROOVE ELEMENTS EXTNDING THEREALONG BEING JOINED BY THE APPLICATION OF LATERALLY INWARDLY DIRECTED CLOSING FORCES AND BEING SEPARATED BY THE APPLICATION OF OPENING FORCES DRWING THE MARGINAL PORTIONS OUTWADLY APART, A SLIDER STRADDLING THE UPPER EDGE OF THE STRIPS AND MOVABLE THEREALONG, SAID RIB ELEMENT BEING THICKER THAN OVERHANGING SIDES OF THE GROOVE ELEMENT TO POSITIVELY INTERLOCK THE RIB ELEMENT THEREIN REQUIRING FORCE FOR SEPARATION, SAID SLIDER HAVING LATERAL SIDES FOR SLIDING ALONG THE OUTER SURFACES OF SAID STRIPS FOR APPLYING THE CLOSING FORCES AND HAVING A BACK RIGIDLY SUPPORTING AND EXTENDING BETWEEN SAID SIDES, UPWARDLY PROJECTING FLEXIBLE OUTWARDLY BENDABLE FLANGES ON THE UPPER EDGES OF SAID MARGINAL PORTIONS, A FINGER GRIPPING EDGE AT THE TOP OF EACH OF THE FLEXIBLE FLANGES WITH AT LEAST ONE OF THE EDGES HAVING A DOWNWARDLY FACING CONTINUOUS SLIDER RETAINING SURFACE, AND A CHANNEL IN SAID SLIDER BACK HAVING A SHAPE CONFORMING TO BE SHAPE OF SAID PROJECTING FLANGES AND TO SAID GRIPPING EDGES AND HAVING AN UPWARDLY FACING SURFACE RIDING BENEATH SAID SLIDER RETAINING SURFACE, SAID SLIDER SIDES FORMING A TUNNEL IN THE REGION OF THE MARGINAL PORTIONS, SAID TUNNEL BEING UNOBSTRUCTED INSIDE AND BEYOND THE SLIDE SO THAT ONLY THE OUTER SURFACES OF THE MARGINAL PORTIONS ARE ENGAGED BY THE SLIDER.