Method and apparatus for forming a row of zigzag coupling elements for slide fasteners

Abstract From the Canadian patent

In a method and apparatus for forming a row of zigzag coupling elements, the whole of a rotating die wheel is heated by a built-in interior heater 50 as to remain at a temperature slightly lower than the temperature at which a monofilament of thermoplastic synthetic resin is deformable, the monofilament being folded in an annular peripheral groove of the die wheel into a row of U-shaped coupling element blanks. Then, immediately before coupling heads are shaped, the monofilament in the form of U-shaped coupling element blanks received in the annular peripheral groove is additionally heated locally by an exterior heater outside of the die wheel such that its temperature rises to a heat …