PIPE FOR OPTICAL FIBER FORCIBLE FEEDING AND ITS MANUFACTURE, AND OPTICAL FIBER FORCIBLE FEEDING METHOD

PURPOSE:To provide the pipe for optical fiber forcible feeding which greatly increases laying length and its manufacture, and the optical fiber feeding method. CONSTITUTION:When the pipe for optical fiber forcible feeding wherein an optical fiber unit is laid is molded by extrusion, part of the outer periphery of the pipe in a soft state is pressed by a die 13 which has molding projections 14 internally and the die 13 is rotated, or projection molding grooves are formed in the outer periphery of a nipple 22 forming pipe holes are formed at the extrusion opening of an extrusion molder and the nipple 22 is rotated at the time of extrusion molding to form forcible feeding pipes 10 and 20. Consequently, projections 11 and 21 which are twisted lengthwise are formed on the internal walls of the pipes 10 and 20 and the tip parts of the projections 11 and 21 are rounded.