Patent ID: 6365253
Filing Date: 2002-04-02
Classification: B29C,B65H,Y10S,Y10T

Abstract:
A method for forming a continuous plastic coil from a straight thermoplastic wire, comprising the steps of:a) heating the thermoplastic wire until it achieves a semi-viscous malleable state; b) injecting the heated wire with an injection nozzle into a helical channel formed by a rotating threaded mandrel axially extending into a stationary sleeve and being radially adjacent therewith, with the wire sliding along the channel in a helical travelling direction to an outlet opening; c) cooling said channel during the injection of the wire therein, wherein said wire will effectively be formed into a plastic coil of a shape corresponding to said helical channel; d) rotating in a common rotative movement the mandrel and the injection nozzle during the injection in a direction opposite the travelling direction and at a speed allowing the continuous plastic coil to be discharged at the outlet opening with an axial translational displacement, while being exempt of any rotational displacement about its longitudinal axis.