Method and apparatus for forming elongated members

Claim 1

IN AN EXTRUDING PROCESS, THE STEPS OF DISCHARGING FROM AN EXTRUDER A TUBE OF PLASTIC WHICH MOVES ALONG A PREDETERMINED PATH, SAID TUBE BEING AT A TEMPERATURE WHICH RENDERS SAID TUBE PLASTICALLY DEFORMABLE; SUCKING THE DEFORMABLE TUBE OF PLASTIC AS IT MOVES ALONG SAID PATH INTO ENGAGEMENT WITH THE INNER SURFACE OF A RIGID SHAPING TUBE SO THAT THE TUBE OF PLASTIC WILL CONFORM TO THE CONFIGURATION OF SAID INNER SURFACE AND WILL HARDEN INTO SAID CONFIGURATION SAID INNER SURFACE HAVING A PERIPHERAL SHAPE MATCHING THE DESIRED FINAL SHAPE OF SAID HARDENED TUBE WITH THE PERIPHERAL SHAPE BEING AT LEAST SLIGHTLY GREATER THAN THE PEERIPHERAL SHAPE OF SAID HEATED DEFORMABLE TUBE; AND SIMULTANEOUSLY DISCHARGING WITH SAID TUBE OF PLASTIC A STREAM OF FOAMABLE, SYNTHETIC, THERMOPLASTIC, RESIN-FORMING COMPOSITION SURROUNDED BY AND LOCATED WITHIN SAID TUBE OF PLASTIC SO THAT SAAID RESIN-FORMING COMPOSITION WILL EXPAND WITHIN AND FILL SAID TUBE OF PLASTIC AND WILL URGE THE TUBE OF PLASTIC AGAINST THE INNER SURFACE OF THE SHAPING TUBE AT LEAST UNTIL SAID TUBE HARDENS.