METHOD OF JOINTING PLASTIC INSULATED CABLE

PURPOSE:To eliminate fluctuation of characteristic of extrusion mold jointing method, by arranging a temperature sensor at the tip of a temperature measur ing rod means which penetrates slidably through the wall face of a metal mold, thereby directly measuring preheat temperature of a cable insulator and a conductor jointing sleeve in contact with resin. CONSTITUTION:A temperature measuring means 30 having a temperature sensor (such as a thermo-couple) at the tip 34 of a rod body 32 is fitted slidably in a through-hole 26 of a metal mold 20. When preheating is carried out, the tem perature measuring means 30 is fully pushed in so as to be brought into contact the tip 34 thereof with a temperature measuring point on the surface 13 of a cable insulator 12 or the surface 15 of a conductor joint sleeve 14. In such a manner, surface temperature is measured directly and continuously. When resin is extruded, the temperature measuring means 30 is fully pulled up. Since the tip 34 of the temperature measuring means 30 contacts tightly with the inside 28 of the through-hole 26, resin dose not leak through the through-hole 26.